import { createLogger } from "@/lib/observability/logger";
import { geolocation } from "@vercel/functions";
import {
  convertToModelMessages,
  createUIMessageStream,
  generateText,
  smoothStream,
  stepCountIs,
  streamText,
} from "ai";
import { eq, sql } from "drizzle-orm";
import { unstable_cache as cache } from "next/cache";
import { after, NextResponse } from "next/server";
import {
  createResumableStreamContext,
  type ResumableStreamContext,
} from "resumable-stream";
import type { ModelCatalog } from "tokenlens/core";
import { fetchModels } from "tokenlens/fetch";
import { getUsage } from "tokenlens/helpers";
import { auth, type UserType } from "@/app/(auth)/auth";
import type { VisibilityType } from "@/components/visibility-selector";
import { entitlementsByUserType } from "@/lib/ai/entitlements";
import type { ChatModel } from "@/lib/ai/models";
import { type RequestHints, systemPrompt } from "@/lib/ai/prompts";
import { myProvider } from "@/lib/ai/providers";
import {
  isFalGptImage2EditModelId,
  submitFalImageTask,
} from "@/lib/ai/providers/fal-image";
import { getLanguageModelById } from "@/lib/ai/dynamic-provider";
import { shouldForceInlineVisionInputs } from "@/lib/ai/model-compat";
import { createDocument } from "@/lib/ai/tools/create-document";
import { getWeather } from "@/lib/ai/tools/get-weather";
import { requestSuggestions } from "@/lib/ai/tools/request-suggestions";
import { updateDocument } from "@/lib/ai/tools/update-document";
import {
  executeDirectVideoGeneration,
  generateVideo,
} from "@/lib/ai/tools/generate-video";
import {
  getAgentRequiredUploadCount,
  normalizeAgentPresetModeConfig,
} from "@/lib/agents/preset-mode-config";
import { buildAgentSceneImageRolePrompt } from "@/lib/agents/scene-image-role-prompt";
import { optimizeAgentSceneWorkflowPrompt } from "@/lib/agents/scene-workflow-prompt-optimizer";
import { getEnabledTools } from "@/lib/ai/tools-registry";
import { isProductionEnvironment } from "@/lib/constants";
import {
  createStreamId,
  deleteChatById,
  getChatById,
  getPointsSystemConfig,
  getUserById,
  getMessageCountByUserId,
  getMessagesByChatId,
  saveChat,
  saveMessages,
  updateMessageById,
  updateChatLastContextById,
  getAgentAiModelWithProvider,
  getAiModelById,
  getEnabledAiModelsWithProvider,
  getSubModelsByParentModelId,
  getAiProviderById,
  checkUserImageQuota,
  consumeUserPoints,
  createAgentPresetExecutionSnapshot,
  createMessageTargetResolution,
  createMediaAssetRelation,
  getAccessibleAgentPresetById,
  getConversationWorkingStateByChatId,
  getMediaAssetsByUserAndUrls,
  getSiteSettings,
  upsertMediaAsset,
} from "@/lib/db/queries";
import { db } from "@/lib/db";
import type { DBMessage } from "@/lib/db/schema";
import {
  agentPreset as agentPresetTable,
  generatedImage,
  message as messageTable,
} from "@/lib/db/schema";
import { generateCanvasImage } from "@/lib/canvas/generate-image";
import {
  detectRequestedStoryboardGrid,
  isGridConfirmationReply,
  type PendingGridConfirmation,
} from "@/lib/ai/conversation-action-resolver";
import {
  bootstrapConversationStateProtocol,
  composeConversationStateProtocol,
  persistAgentPresetTurn,
  persistClarificationTurn,
  setConversationStateProtocolEventObserver,
  persistResolvedTargetTurn,
  persistImageWorkflowTurn,
  persistPromptOnlyTurn,
  resolveGridConfirmationRequest,
  resolveTargetExecutionOverride,
  persistStoryboardConfirmedTurn,
  persistStoryboardExecutionCompletedTurn,
  persistStoryboardExecutionStartedTurn,
  persistStoryboardRevisionTurn,
  persistStoryboardAssistantTurn,
  persistVideoGenerationCompletedTurn,
  persistVideoGenerationFailedTurn,
  persistVideoGenerationStartedTurn,
  persistWorkflowCancelledTurn,
} from "@/lib/ai/conversation-state-protocol";
import { resolveChatMediaInput } from "@/lib/ai/context-memory/media-input";
import { resolveTargetAssets } from "@/lib/ai/context-memory/target-resolution";
import type {
  ResolvedChatMediaInput,
  ResolvedTargetAssets,
} from "@/lib/ai/context-memory/types";
import { ChatSDKError } from "@/lib/errors";
import {
  getFriendlyRateLimitMessage,
  getRequestErrorMessage,
  isRateLimitError,
} from "@/lib/request-error";
import {
  resolveClarificationBypass,
  resolveClarificationMessage,
} from "@/lib/ai/runtime/clarification-interruption";
import {
  buildAgentToolImagesMarkdown,
  buildAgentToolVideoMarkdown,
  prependImageModelBadge,
} from "@/lib/ai/runtime/agent-media-markdown";
import { saveGeneratedImages } from "@/lib/ai/runtime/generated-image-persistence";
import {
  recordAiModelHealthFailure,
  recordAiModelHealthSuccess,
} from "@/lib/ai/runtime/model-health";
import type { FalImageEditTaskMetadata } from "@/lib/ai/runtime/fal-image-edit-task";
import { saveAssistantTextOnlyMessage } from "@/lib/ai/runtime/assistant-message-persistence";
import { resolveCanvasAgentClarificationGate } from "@/lib/ai/runtime/middlewares/canvas-agent-clarification-gate";
import {
  executeDirectAgentImageEditTool,
  isDirectAgentImageEditServiceError,
} from "@/lib/ai/runtime/direct-agent-image-edit-executor";
import {
  executeDirectAgentImageAnalysis,
  executeDirectAgentImageGeneration,
  executeDirectAgentVideoGeneration,
} from "@/lib/ai/runtime/direct-agent-media-executors";
import {
  buildDirectAgentAnalysisAssistantText,
  buildDirectAgentImageEditAssistantText,
  buildDirectAgentImageGenerationAssistantText,
  buildDirectAgentVideoGenerationAssistantText,
} from "@/lib/ai/runtime/direct-agent-response-builders";
import {
  buildDirectAgentAnalyzeCompletedProgress,
  buildDirectAgentAnalyzeFailedProgress,
  buildDirectAgentAnalyzePlanningProgress,
  buildDirectAgentImageContextProgress,
  buildDirectAgentImageEditCompletedProgress,
  buildDirectAgentImageEditExecutingProgress,
  buildDirectAgentImageEditFailedProgress,
  buildDirectAgentImageEditSelectProgress,
  buildDirectAgentImageGenerateCompletedProgress,
  buildDirectAgentImageGenerateExecutingProgress,
  buildDirectAgentImageGenerateFailedProgress,
  buildDirectAgentImageGenerateSelectProgress,
  buildDirectAgentVideoGenerateCompletedProgress,
  buildDirectAgentVideoGenerateExecutingProgress,
  buildDirectAgentVideoGenerateFailedProgress,
  buildDirectAgentVideoGenerateSelectProgress,
} from "@/lib/ai/runtime/direct-agent-progress";
import {
  safePersistDirectAgentAnalyzeTurn,
  safePersistDirectAgentImageEditTurn,
  safePersistDirectAgentVideoCompletedTurn,
  safePersistDirectAgentVideoFailedTurn,
} from "@/lib/ai/runtime/direct-agent-working-state";
import {
  getDirectAgentToolErrorMessage,
  getDirectAgentToolLabel,
  getDirectAgentToolTargetMissingMessage,
  isDirectAgentImageEditToolName,
  resolveDirectAgentToolContext,
} from "@/lib/ai/runtime/direct-agent-execution";
import {
  pruneTaskBoundaryContext,
  pruneTaskBoundaryHistoryMessages,
} from "@/lib/ai/runtime/task-boundary-context-pruner";
import {
  resolveAgentModelSlotDescriptor,
  upsertAgentModelSlot,
  type AgentModelSlots,
} from "@/lib/ai/runtime/agent-model-slots";
import { isPureGreetingTurnRequest } from "@/lib/ai/runtime/task-boundary-classifier";
import {
  getProviderHealthSnapshot,
  recordProviderHealthFailure,
  recordProviderHealthSuccess,
  shouldAvoidProvider,
} from "@/lib/ai/runtime/provider-health";
import { arbitrateAgentIntent } from "@/lib/ai/runtime/intent-arbiter";
import { buildAgentRoleIdentityInstruction } from "@/lib/ai/runtime/agent-role-profile";
import { getVideoStoryboardConfig } from "@/lib/video-agent/config";
import { runRuxaNineGridPipeline } from "@/lib/video-agent/pipeline/ruxa-nine-grid-pipeline";
import {
  buildStoryboardConfirmedAck,
  executeStoryboardConfirmedWorkflow,
  handleStoryboardWorkflowFollowup,
} from "@/lib/video-agent/storyboard-chat-followup";
import {
  buildStoryboardPreferenceMemoryUpdate,
} from "@/lib/video-agent/storyboard-preference-memory";
import {
  attachVideoStoryboardTaskMessage,
  getLatestActiveVideoStoryboardTaskByChatId,
  markVideoStoryboardAwaitingConfirmation,
  markVideoStoryboardConfirmed,
  markVideoStoryboardDraftForRevision,
  cancelVideoStoryboardTaskByUser,
} from "@/lib/video-agent/task-store";
import type { StoryboardModelCandidate } from "@/lib/video-agent/types";
import type { ChatMessage } from "@/lib/types";
import type { AppUsage } from "@/lib/usage";
import { convertToUIMessages, generateUUID } from "@/lib/utils";
import { isAiModelAgentAuto } from "@/lib/db/ai-model-flags";
import type {
  AgentExecutionPlan,
  AgentPreparedExecution,
} from "@/lib/ai/auto-agent-graph";
import { generateTitleFromUserMessage } from "../../actions";
import { type PostRequestBody, postRequestBodySchema } from "./schema";
import { isAiModelMultimodal } from "@/lib/db/ai-model-flags";
import {
  createChatApiFailureResponse,
  getBudgetedTimeout,
  getChatStreamErrorMessage,
  OperationTimeoutError,
  withOperationTimeout,
} from "./_lib/errors";
import {
  applyResolvedTargetImagesToLastUserMessage,
  buildAutoModeFallbackMessage,
  buildPromptOnlyOptimizationSeed,
  buildPromptOnlyReply,
  collectImageInputsFromMessageParts,
  convertMessagesWithImages,
  ensureImageAnalysisSummarySection,
  ensureStructuredAgentFriendlyMessage,
  extractMessageImageAssetIds,
  extractMessageImageUrls,
  injectHistoryImagesToLastUserMessage,
  normalizeAssistantImageMarkdown,
  normalizeResolvedTargetImageUrls,
  shouldEnrichImageAnalysisText,
  summarizeTargetImageUrl,
} from "./_lib/image-media";
import {
  buildImageFallbackCandidates,
  generateImageWithFailoverCandidate,
  getImageCrossProviderCandidates,
  IMAGE_FAILOVER_PROVIDER_ALLOWLIST,
  normalizeFailoverErrorMessage,
  setImageFallbackModelCooldown,
  shouldCooldownImageFallbackModel,
} from "./_lib/image-failover";
import {
  buildAgentSceneWorkflowPrompt,
  buildAgentSlotPrompt,
  buildOptimizedAgentSceneWorkflowPrompt,
  dedupeAgentSlotPromptAgainstWorkflow,
  extractCurrentMessageImageParts,
  getSceneUploadedImageBreakdown,
  normalizeAgentSupplementPrompt,
  resolveScenePromptOptimizationImageUrls,
  type AgentPresetMessageImagePart,
} from "./_lib/agent-scene-workflow";
import {
  analyzeReplacementExecutionPlan,
  buildAgentReplacementPrompt,
  normalizeAgentModeDetailReplacementStrategy,
  normalizeAgentModeReferences,
  normalizeAgentModeSourceImages,
  normalizeReplacementResultImage,
  resolveDirectReplacementModelRef,
  resolveImagePartsByReferenceExclusion,
  resolveReplacementReferenceGeometry,
  resolveReplacementScenePlanningRuntime,
} from "./_lib/detail-replacement";
import {
  normalizeAgentReportForDisplay,
  sanitizeAgentOutputSettingsSection,
} from "./_lib/agent-output";
import {
  consumeGeneratedVideoPoints,
  getModelCreditCost,
} from "./_lib/billing";
import {
  ANNOTATION_SYSTEM_PROMPT,
  applyHiddenPromptToMessages,
  applyOptimizedPromptToLatestUserMessage,
  convertImageUrlToBase64,
  hasAnnotatedImage,
  injectOptimizedPromptSection,
} from "./_lib/message-preparation";
import {
  resolveModelDisplayNameByModelId,
  resolveModelEntryByRuntimeModelId,
  resolveModelRefByRuntimeModelId,
} from "./_lib/model-resolver";
import { normalizeAssistantPartsForPersistence } from "./_lib/persistence";
import {
  buildAgentTargetLockPayload,
  createSseResponse,
  runBoundedParallel,
  safeWriteStreamChunk,
  startStreamKeepalive,
  type StreamWriter,
  writeAgentProgressChunk,
  writeAgentTargetLockChunk,
  writeAssistantTextChunk,
  writeCanvasMediaChunk,
  writeImageGenerationStatusChunk,
  writeProtocolDebugChunk,
} from "./_lib/stream";
import {
  extractVideoUrlFromText,
  getSupportedVideoModesForModel,
  isImageGenerationModelType,
  isVideoProviderType,
  resolveStoryboardModelCandidates,
  scheduleVideoArchive,
  selectBestVideoSubModelForMode,
  type VideoModeType,
} from "./_lib/video-models";

const chatApiLogger = createLogger("chat.route");


const AGENT_REPLACEMENT_PARALLEL_WORKER_COUNT = Math.max(
  1,
  Math.min(8, Number(process.env.AGENT_REPLACEMENT_PARALLEL_WORKER_COUNT || 6) || 6),
);

async function replayAssistantMessagesForDuplicateRequest({
  chatId,
  userMessageId,
  writer,
  source,
  waitMs = DUPLICATE_REQUEST_WAIT_MS,
}: {
  chatId: string;
  userMessageId: string;
  writer: StreamWriter;
  source: string;
  waitMs?: number;
}) {
  const startedAt = Date.now();
  const seenAssistantMessageIds = new Set<string>();

  while (Date.now() - startedAt < waitMs) {
    try {
      const dbMessages = await getMessagesByChatId({ id: chatId });
      const userMessageIndex = dbMessages.findIndex((msg) => msg.id === userMessageId);

      if (userMessageIndex >= 0) {
        const assistantMessages = dbMessages
          .slice(userMessageIndex + 1)
          .filter((msg) => msg.role === "assistant");

        if (assistantMessages.length > 0) {
          for (const assistantMessage of assistantMessages) {
            if (seenAssistantMessageIds.has(assistantMessage.id)) continue;
            seenAssistantMessageIds.add(assistantMessage.id);

            safeWriteStreamChunk(
              writer,
              {
                type: "data-appendMessage",
                data: JSON.stringify({
                  id: assistantMessage.id,
                  role: "assistant",
                  parts: assistantMessage.parts,
                }),
              },
              `${source}:replay`,
            );
          }

          return;
        }
      }
    } catch (error) {
      chatApiLogger.warn(`[Chat API] Failed duplicate replay fetch (${source})`, error);
    }

    safeWriteStreamChunk(
      writer,
      {
        type: "data-keepalive",
        data: JSON.stringify({ ts: Date.now(), source }),
      },
      `${source}:keepalive`,
    );

    await sleep(1000);
  }
}

type ChatImageParams = NonNullable<PostRequestBody["imageParams"]>;
type AgentRecommendedImageParams = {
  aspectRatio?: string;
  imageSize?: string;
  imageCount?: number;
  negativePrompt?: string;
  promptExtend?: boolean;
};

type ChatVideoParams = NonNullable<PostRequestBody["videoParams"]>;
type ChatVideoParamsDraft = Partial<ChatVideoParams>;
type AgentRecommendedVideoParams = {
  mode?: "text-to-video" | "first-frame" | "first-last-frame" | "reference-images";
  resolution?: "480p" | "720p" | "1080p";
  ratio?: string;
  duration?: number;
  generateAudio?: boolean;
  cameraMove?: string;
};

type AgentVideoPlan = {
  script: string;
  storyboard: Array<{
    shot: number;
    title: string;
    duration: number;
    description: string;
    prompt: string;
    camera?: string;
  }>;
  finalPrompt: string;
  negativePrompt?: string;
  recommendedVideoParams?: AgentRecommendedVideoParams;
};

function hasUserCustomizedImageParams(params?: PostRequestBody["imageParams"]): boolean {
  if (!params) return false;
  const customizedAspectRatio =
    typeof params.aspectRatio === "string" && params.aspectRatio.trim() && params.aspectRatio !== "auto";
  const customizedImageSize =
    typeof params.imageSize === "string" && params.imageSize.trim() && params.imageSize.toUpperCase() !== "2K";
  const customizedImageCount = typeof params.imageCount === "number" && params.imageCount !== 1;
  const customizedPromptExtend = typeof params.promptExtend === "boolean";
  const customizedAdvanced = Boolean(
    params.size || params.seed !== undefined || params.n || params.negativePrompt || customizedPromptExtend
  );
  return customizedAspectRatio || customizedImageSize || customizedImageCount || customizedAdvanced;
}

function mergeImageParamsWithAgentRecommendation(params: {
  incoming?: PostRequestBody["imageParams"];
  recommended?: AgentRecommendedImageParams;
  intent?: "image_edit" | "image_gen" | "vision" | "video_gen" | "chat";
  hasUserCustomSettings: boolean;
}): PostRequestBody["imageParams"] {
  const { incoming, recommended, intent, hasUserCustomSettings } = params;
  const base: ChatImageParams = { ...(incoming || {}) };
  if (!recommended) {
    return Object.keys(base).length > 0 ? base : undefined;
  }

  const merged: ChatImageParams = {
    ...base,
    negativePrompt:
      typeof recommended.negativePrompt === "string" && recommended.negativePrompt.trim()
        ? recommended.negativePrompt.trim()
        : base.negativePrompt,
    promptExtend:
      typeof recommended.promptExtend === "boolean"
        ? recommended.promptExtend
        : base.promptExtend,
  };

  if (!hasUserCustomSettings) {
    if (recommended.aspectRatio) merged.aspectRatio = recommended.aspectRatio;
    if (recommended.imageSize) merged.imageSize = recommended.imageSize;
    if (typeof recommended.imageCount === "number") merged.imageCount = recommended.imageCount;
  }

  if (intent === "image_edit") {
    merged.imageCount = 1;
    if (typeof base.promptExtend !== "boolean") {
      merged.promptExtend = false;
    }
  }

  return Object.keys(merged).length > 0 ? merged : undefined;
}

function hasUserCustomizedVideoParams(params?: PostRequestBody["videoParams"]): boolean {
  if (!params) return false;
  const defaults = {
    mode: "text-to-video",
    resolution: "720p",
    ratio: "16:9",
    duration: 5,
    generateAudio: true,
    cameraMove: "none",
  } as const;

  if (params.mode && params.mode !== defaults.mode) return true;
  if (params.resolution && params.resolution !== defaults.resolution) return true;
  if (params.ratio && params.ratio !== defaults.ratio) return true;
  if (typeof params.duration === "number" && params.duration !== defaults.duration) return true;
  if (typeof params.generateAudio === "boolean" && params.generateAudio !== defaults.generateAudio)
    return true;
  if (typeof params.cameraMove === "string" && params.cameraMove !== defaults.cameraMove)
    return true;
  if (typeof params.seed === "number") return true;
  return false;
}

function mergeVideoParamsWithAgentRecommendation(params: {
  incoming?: PostRequestBody["videoParams"];
  recommended?: AgentRecommendedVideoParams;
  hasUserCustomSettings: boolean;
}): PostRequestBody["videoParams"] {
  const { incoming, recommended, hasUserCustomSettings } = params;
  const base: ChatVideoParamsDraft = { ...(incoming || {}) };
  if (!recommended) {
    return Object.keys(base).length > 0 ? (base as ChatVideoParams) : undefined;
  }

  const merged: ChatVideoParamsDraft = { ...base };
  if (!hasUserCustomSettings) {
    if (recommended.mode) merged.mode = recommended.mode;
    if (recommended.resolution) merged.resolution = recommended.resolution;
    if (recommended.ratio) merged.ratio = recommended.ratio;
    if (typeof recommended.duration === "number") merged.duration = recommended.duration;
    if (typeof recommended.generateAudio === "boolean") {
      merged.generateAudio = recommended.generateAudio;
    }
    if (recommended.cameraMove) merged.cameraMove = recommended.cameraMove;
  }

  if (!merged.mode) {
    merged.mode = recommended.mode || (incoming?.mode as ChatVideoParams["mode"]) || "text-to-video";
  }
  if (!merged.resolution) {
    merged.resolution =
      recommended.resolution || (incoming?.resolution as ChatVideoParams["resolution"]) || "720p";
  }
  if (!merged.ratio) {
    merged.ratio = recommended.ratio || incoming?.ratio || "16:9";
  }
  if (typeof merged.duration !== "number") {
    merged.duration = recommended.duration || incoming?.duration || 5;
  }

  return Object.keys(merged).length > 0 ? (merged as ChatVideoParams) : undefined;
}

export const maxDuration = 600; // 10 分钟，用于支持图片编辑等耗时任务

let globalStreamContext: ResumableStreamContext | null = null;
const inFlightChatRequests = new Map<string, number>();
const IN_FLIGHT_REQUEST_TTL_MS = 5 * 60 * 1000;
const DUPLICATE_REQUEST_WAIT_MS = 2 * 60 * 1000;
const CHAT_PRE_RESPONSE_SOFT_TIMEOUT_MS = 55_000;
const SMART_AUTO_GRAPH_TIMEOUT_MS = 28_000;
const SMART_AUTO_FALLBACK_TIMEOUT_MS = 20_000;
const SMART_AUTO_IMAGE_SUMMARY_TIMEOUT_MS = 18_000;
const DEFAULT_STREAM_KEEPALIVE_INTERVAL_MS = 12_000;
const CHAT_CREATION_LOOKUP_RETRY_DELAYS_MS = [60, 180, 360] as const;

const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));

async function findChatWithRetry(chatId: string) {
  let currentChat = await getChatById({ id: chatId });
  if (currentChat) {
    return currentChat;
  }

  for (const delayMs of CHAT_CREATION_LOOKUP_RETRY_DELAYS_MS) {
    await sleep(delayMs);
    currentChat = await getChatById({ id: chatId });
    if (currentChat) {
      return currentChat;
    }
  }

  return null;
}

const getTokenlensCatalog = cache(
  async (): Promise<ModelCatalog | undefined> => {
    try {
      return await fetchModels();
    } catch (err) {
      chatApiLogger.warn("TokenLens: catalog fetch failed, using default catalog", err);
      return; // tokenlens helpers will fall back to defaultCatalog
    }
  },
  ["tokenlens-catalog"],
  { revalidate: 24 * 60 * 60 } // 24 hours
);

export function getStreamContext() {
  if (!globalStreamContext) {
    try {
      globalStreamContext = createResumableStreamContext({
        waitUntil: after,
      });
    } catch (error: any) {
      if (error.message.includes("REDIS_URL")) {
        chatApiLogger.info(" > Resumable streams are disabled due to missing REDIS_URL");
      } else {
        chatApiLogger.error("console_error", error);
      }
    }
  }

  return globalStreamContext;
}

export async function POST(request: Request) {
  let requestBody: PostRequestBody;
  let requestDedupKey: string | null = null;
  let acquiredInFlightLock = false;

  try {
    const json = await request.json();
    chatApiLogger.info("[Chat API] Received request body:", JSON.stringify(json, null, 2));
    requestBody = postRequestBodySchema.parse(json);
  } catch (error) {
    chatApiLogger.error("[Chat API] Schema validation failed:", error);
    return new ChatSDKError("bad_request:api").toResponse();
  }

  try {
    const {
      id,
      message,
      agentPresetId,
      selectedChatModel,
      selectedVisibilityType,
      composerMode,
      hiddenPrompt,
      workflowPromptOptimizationEnabled,
      autoContext,
      contextPayload,
      agentModePayload,
      deepThinkingEnabled,
      debugProtocol,
    }: {
      id: string;
      message: ChatMessage;
      agentPresetId?: string;
      selectedChatModel: ChatModel["id"];
      selectedVisibilityType: VisibilityType;
      composerMode?: "agent" | "image" | "video" | "detail";
      hiddenPrompt?: string;
      workflowPromptOptimizationEnabled?: boolean;
      autoContext?: string;
      contextPayload?: PostRequestBody["contextPayload"];
      agentModePayload?: PostRequestBody["agentModePayload"];
      deepThinkingEnabled?: boolean;
      debugProtocol?: boolean;
    } = requestBody;
    const requestStartedAt = Date.now();
    const requestOrigin = (() => {
      try {
        return new URL(request.url).origin;
      } catch {
        return "";
      }
    })();
    const requestTextContent = message.parts
      .filter((part): part is { type: "text"; text: string } => part.type === "text")
      .map((part) => part.text)
      .join(" ")
      .trim();
    const autoContextText = typeof autoContext === "string" ? autoContext.trim() : "";

    const now = Date.now();
    for (const [key, startedAt] of inFlightChatRequests.entries()) {
      if (now - startedAt > IN_FLIGHT_REQUEST_TTL_MS) {
        inFlightChatRequests.delete(key);
      }
    }

    requestDedupKey = `${id}:${message.id}`;
    if (inFlightChatRequests.has(requestDedupKey)) {
      chatApiLogger.warn(`[Chat API] Duplicate in-flight request ignored (chatId=${id}, messageId=${message.id})`);
      const duplicateStream = createUIMessageStream({
        execute: async ({ writer }) => {
          await replayAssistantMessagesForDuplicateRequest({
            chatId: id,
            userMessageId: message.id,
            writer,
            source: "duplicate-in-flight",
          });
        },
      });
      return createSseResponse(duplicateStream);
    }
    inFlightChatRequests.set(requestDedupKey, now);
    acquiredInFlightLock = true;

    let finalModelId = selectedChatModel;

    // 🆕 存储智能模式的相关信息
    let smartAutoFriendlyMessage: string | undefined;  // AI的自然对话回复
    let smartAutoOptimizedPrompt: string | undefined;  // 优化后的提示词（不修改用户消息，只用于API调用）
    let smartAutoPromptFromVideoPlan = false;
    let smartAutoRecommendedImageParams: AgentRecommendedImageParams | undefined;
    let smartAutoVideoPlan: AgentVideoPlan | undefined;
    let smartAutoRecommendedVideoParams: AgentRecommendedVideoParams | undefined;
    let smartAutoPlan: AgentExecutionPlan | undefined;
    let smartAutoExecution: AgentPreparedExecution | undefined;
    let smartAutoDetectedIntent: "image_edit" | "vision" | "image_gen" | "video_gen" | "chat" | undefined;
    let smartAutoHistoryImages: string[] = [];         // 从历史对话中提取的图片URL（支持多张）
    let smartAutoNeedsClarification = false;           // 是否需要先追问用户
    let smartAutoClarificationQuestion: string | undefined;
    let requestResolvedMediaInput: ResolvedChatMediaInput | null = null;
    let requestTargetResolution: ResolvedTargetAssets | null = null;
    let requestWorkingState:
      | Awaited<ReturnType<typeof getConversationWorkingStateByChatId>>
      | null = null;
    let storyboardPreferenceMemory = null;
    let imageWorkflowMemory = null;
    let reusablePromptMemory = null;
    let confirmedPromptForConversationState: string | undefined;
    let smartAutoHistoryMessagesFromDb: DBMessage[] = [];
    let smartAutoMediaHistoryMessagesFromDb: DBMessage[] = [];
    let preferredAgentModelId: string | undefined;
    let configuredAgentConversationModelId: string | undefined;
    let agentModelSlots: AgentModelSlots = {};
    let pendingGridConfirmation:
      | PendingGridConfirmation
      | null = null;
    let shouldAskGridConfirmation = false;
    const deepThinkingOn = deepThinkingEnabled !== false;
    const shouldRespectDirectComposerMode =
      composerMode === "image" || composerMode === "video" || composerMode === "detail";
    const shouldIsolateDirectComposerContext = shouldRespectDirectComposerMode;
    let shouldRunAgentConversation = finalModelId === "auto";
    let shouldKeepSelectedModel = false;
    if (shouldRespectDirectComposerMode && shouldRunAgentConversation) {
      shouldRunAgentConversation = false;
      chatApiLogger.info(`[Smart Auto Mode] ⛳ Direct composer mode (${composerMode}) disables initial auto-agent routing`);
    }
    const pendingProtocolDebugEvents: Array<{ phase: string; payload: Record<string, unknown> }> = [];
    const requestedModelId = selectedChatModel;
    let requestedModelProviderType: string | undefined;
    let requestedModelIsFixedVisual = false;
    let requestedModelIsConversationMultimodal = false;
    let requestedModelConfig: Awaited<ReturnType<typeof getAiModelById>> | null = null;

    if (!shouldRunAgentConversation && requestedModelId !== "auto") {
      const selectedModelIsUUID =
        /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(requestedModelId);
      let selectedModelConfig = selectedModelIsUUID
        ? await getAiModelById({ id: requestedModelId })
        : null;
      let selectedModelProviderType: string | undefined;

      if (!selectedModelConfig) {
        const enabledModels = await getEnabledAiModelsWithProvider(false);
        const matchedModel = enabledModels.find(
          ({ model }) => model.id === requestedModelId || model.modelId === requestedModelId
        );
        if (matchedModel) {
          selectedModelConfig = matchedModel.model;
          selectedModelProviderType = matchedModel.provider.type as string;
        }
      }

      if (selectedModelConfig && !selectedModelProviderType) {
        const selectedProvider = await getAiProviderById({
          id: selectedModelConfig.providerId,
        });
        selectedModelProviderType = selectedProvider?.type as string | undefined;
      }

      requestedModelConfig = selectedModelConfig;
      requestedModelProviderType = selectedModelProviderType;

      if (selectedModelConfig) {
        const isFixedVisualModel =
          !selectedModelConfig.isSubModel &&
          (
            isImageGenerationModelType(selectedModelProviderType, selectedModelConfig) ||
            isVideoProviderType(selectedModelProviderType, selectedModelConfig)
          );
        const isConversationMultimodalModel =
          !selectedModelConfig.isSubModel &&
          isAiModelMultimodal(selectedModelConfig) &&
          !isImageGenerationModelType(selectedModelProviderType, selectedModelConfig) &&
          !isVideoProviderType(selectedModelProviderType, selectedModelConfig);
        requestedModelIsFixedVisual = isFixedVisualModel;
        requestedModelIsConversationMultimodal = isConversationMultimodalModel;

        if (deepThinkingOn) {
          if (isAiModelAgentAuto(selectedModelConfig)) {
            if (shouldRespectDirectComposerMode) {
              chatApiLogger.info(`[Smart Auto Mode] ⛳ Respect direct composer mode (${composerMode}), skip forcing agent-only routing for: ${selectedModelConfig.displayName}`);
            } else {
              shouldRunAgentConversation = true;
              shouldKeepSelectedModel = false;
              preferredAgentModelId = selectedModelConfig.id;
              configuredAgentConversationModelId = selectedModelConfig.id;
              chatApiLogger.info(`[Smart Auto Mode] 🧠 Agent-only model detected, force auto routing: ${selectedModelConfig.displayName}`);
            }
          } else if (isFixedVisualModel || isConversationMultimodalModel) {
            if (shouldRespectDirectComposerMode) {
              chatApiLogger.info(`[Smart Auto Mode] ⛳ Respect direct composer mode (${composerMode}), keep direct execution model: ${selectedModelConfig.displayName}`);
            } else {
              shouldRunAgentConversation = true;
              shouldKeepSelectedModel = true;
              preferredAgentModelId = selectedModelConfig.id;
              chatApiLogger.info(`[Smart Auto Mode] 🎯 Agent conversation enabled for selected model: ${selectedModelConfig.displayName} (${selectedModelProviderType || "unknown"}), preferredAgentModelId=${preferredAgentModelId}`);
            }
          }
        } else if (
          isFixedVisualModel ||
          isConversationMultimodalModel ||
          isAiModelAgentAuto(selectedModelConfig)
        ) {
          chatApiLogger.info(`[Smart Auto Mode] ⏭️ Deep thinking disabled, skip agent analysis for: ${selectedModelConfig.displayName}`);
        }
      }
    }

    if (shouldRunAgentConversation && !preferredAgentModelId) {
      const configuredAgentModel = await getAgentAiModelWithProvider().catch((agentModelError) => {
        chatApiLogger.warn("[Chat API] Failed to load configured agent model:", agentModelError);
        return null;
      });

      if (configuredAgentModel?.model?.id) {
        preferredAgentModelId = configuredAgentModel.model.id;
        configuredAgentConversationModelId = configuredAgentModel.model.id;
        agentModelSlots = upsertAgentModelSlot(agentModelSlots, "planner", {
          modelId: configuredAgentModel.model.id,
          displayName: configuredAgentModel.model.displayName || configuredAgentModel.model.modelId,
          providerId: configuredAgentModel.model.providerId,
          providerType: configuredAgentModel.provider.type,
          providerKey: configuredAgentModel.model.providerId,
          source: "configured_agent_default",
          reason: "agent_default_model",
        });
        agentModelSlots = upsertAgentModelSlot(agentModelSlots, "analyzer", {
          modelId: configuredAgentModel.model.id,
          displayName: configuredAgentModel.model.displayName || configuredAgentModel.model.modelId,
          providerId: configuredAgentModel.model.providerId,
          providerType: configuredAgentModel.provider.type,
          providerKey: configuredAgentModel.model.providerId,
          source: "configured_agent_default",
          reason: "agent_default_model",
        });
        chatApiLogger.info(`[Smart Auto Mode] 🧠 Loaded configured agent conversation model: ${configuredAgentModel.model.displayName}`);
      }
    }

    const hasCurrentMessageMediaInput = message.parts.some((part: any) =>
      part?.type === "file" || part?.type === "image" || part?.type === "image_url"
    );
    if (
      shouldRunAgentConversation &&
      isPureGreetingTurnRequest(requestTextContent) &&
      !hasCurrentMessageMediaInput
    ) {
      const session = await auth();

      if (!session?.user) {
        return new ChatSDKError("unauthorized:chat").toResponse();
      }

      const greetingMessage = "你好，我在。你可以直接告诉我想做什么：生图、修图、生成视频、分析图片都可以。";
      const fastPathTitle = requestTextContent.trim().slice(0, 80) || "新对话";
      await saveChat({
        id,
        userId: session.user.id,
        title: fastPathTitle,
        visibility: selectedVisibilityType,
      });

      const greetingChat = await findChatWithRetry(id);
      if (!greetingChat) {
        throw new ChatSDKError("bad_request:database", "Failed to save chat");
      }

      if (greetingChat.userId !== session.user.id) {
        return new ChatSDKError("forbidden:chat").toResponse();
      }

      const greetingStream = createUIMessageStream({
        execute: async ({ writer }) => {
          const messageId = generateUUID();
          writeAssistantTextChunk(writer, greetingMessage, "greeting-fast-path", messageId);

          await saveMessages({
            messages: [
              {
                id: message.id,
                chatId: id,
                role: "user",
                parts: message.parts as any,
                attachments: [],
                createdAt: new Date(),
                videoStorageStatus: null,
                temporaryVideoUrl: null,
                permanentVideoUrl: null,
                archivedAt: null,
                videoMetadata: null,
              },
              {
                id: messageId,
                chatId: id,
                role: "assistant",
                parts: [{ type: "text", text: greetingMessage }],
                attachments: [],
                createdAt: new Date(),
                videoStorageStatus: null,
                temporaryVideoUrl: null,
                permanentVideoUrl: null,
                archivedAt: null,
                videoMetadata: null,
              },
            ],
          });
        },
      });

      return createSseResponse(greetingStream);
    }

    const allowAgentVideoGeneration =
      Boolean(requestBody.videoParams) ||
      isVideoProviderType(requestedModelProviderType, requestedModelConfig || undefined);
    let smartAutoWorkflowDecision:
      | {
          action?: string;
          workflowId?: string;
          workflowType?: string;
          allowWorkflowExecution?: boolean;
        }
      | undefined;
    const activeStoryboardTaskForChat = shouldIsolateDirectComposerContext
      ? null
      : await getLatestActiveVideoStoryboardTaskByChatId({
          chatId: id,
        }).catch((storyboardLookupError) => {
          chatApiLogger.warn("[Chat API] Failed to preload active storyboard task before smart auto mode:", storyboardLookupError);
          return null;
        });

    requestWorkingState = shouldIsolateDirectComposerContext
      ? null
      : await getConversationWorkingStateByChatId({
          chatId: id,
        }).catch((workingStatePreloadError) => {
          chatApiLogger.warn("[Chat API] Failed to preload conversation working state before smart auto mode:", workingStatePreloadError);
          return null;
        });
    const hasImageInputForConversationAction = message.parts.some((part: any) =>
      part?.type === "file" || part?.type === "image" || part?.type === "image_url"
    );
        const conversationStateBootstrap = bootstrapConversationStateProtocol({
          text: requestTextContent,
          workingState: requestWorkingState,
          activeStoryboardTask: activeStoryboardTaskForChat,
          hasImageInputForPromptCarryForward: hasImageInputForConversationAction,
          hasCanvasSelection: Boolean(contextPayload?.selectedNodeIds?.length),
        });
        chatApiLogger.info("[ConversationStateProtocol] Bootstrap:", {
          action: conversationStateBootstrap.actionResolution.kind,
          taskType: conversationStateBootstrap.taskBoundaryDecision.taskType,
          taskMode: conversationStateBootstrap.taskBoundaryDecision.taskMode,
          hasPromptMemory: Boolean(conversationStateBootstrap.promptMemory?.optimizedPrompt),
          hasImageWorkflowMemory: Boolean(conversationStateBootstrap.imageWorkflowMemory),
          hasStoryboardPreferenceMemory: Boolean(conversationStateBootstrap.storyboardPreferenceMemory),
          hasPendingGridConfirmation: Boolean(conversationStateBootstrap.pendingGridConfirmation),
          hasActiveStoryboardTask: Boolean(conversationStateBootstrap.activeStoryboardTask?.task?.id),
        });
        pendingProtocolDebugEvents.push({
          phase: "bootstrap",
          payload: {
            action: conversationStateBootstrap.actionResolution.kind,
            taskBoundary: conversationStateBootstrap.taskBoundaryDecision,
            pendingGridConfirmation: conversationStateBootstrap.pendingGridConfirmation,
            hasPromptMemory: Boolean(conversationStateBootstrap.promptMemory?.optimizedPrompt),
            hasImageWorkflowMemory: Boolean(conversationStateBootstrap.imageWorkflowMemory),
            hasStoryboardPreferenceMemory: Boolean(conversationStateBootstrap.storyboardPreferenceMemory),
            hasActiveStoryboardTask: Boolean(conversationStateBootstrap.activeStoryboardTask?.task?.id),
          },
        });
        storyboardPreferenceMemory = conversationStateBootstrap.storyboardPreferenceMemory;
        imageWorkflowMemory = conversationStateBootstrap.imageWorkflowMemory;
        reusablePromptMemory = conversationStateBootstrap.promptMemory;
        pendingGridConfirmation = conversationStateBootstrap.pendingGridConfirmation;
        confirmedPromptForConversationState = conversationStateBootstrap.confirmedPrompt;
        const resolvedConversationAction = conversationStateBootstrap.actionResolution;
        const taskBoundaryDecision = conversationStateBootstrap.taskBoundaryDecision;
        const taskBoundaryRequiresAgentConversation =
          taskBoundaryDecision.taskType === "prompt_only" ||
          taskBoundaryDecision.taskType === "analysis_only" ||
          taskBoundaryDecision.taskType === "execution_image" ||
          taskBoundaryDecision.taskType === "execution_video" ||
          taskBoundaryDecision.taskType === "workflow_followup";
    const taskBoundaryOverridesLegacyWorkflow =
      taskBoundaryDecision.taskType === "greeting" ||
      taskBoundaryDecision.taskType === "chat" ||
      taskBoundaryDecision.taskType === "analysis_only" ||
      taskBoundaryDecision.taskType === "prompt_only";
        const prunedTaskBoundaryContext = pruneTaskBoundaryContext({
          decision: taskBoundaryDecision,
          contextPayload: contextPayload || undefined,
          autoContextText: autoContextText || undefined,
          workingState: requestWorkingState || undefined,
          hasCurrentImageInput: hasImageInputForConversationAction,
        });
        const effectiveContextPayload = prunedTaskBoundaryContext.contextPayload;
        const effectiveAutoContextText = prunedTaskBoundaryContext.autoContextText || "";
        const effectiveWorkingState = prunedTaskBoundaryContext.workingState;

    if (taskBoundaryRequiresAgentConversation && !shouldRunAgentConversation) {
      if (shouldRespectDirectComposerMode) {
        chatApiLogger.info(`[Smart Auto Mode] ⛳ Respect direct composer mode (${composerMode}), skip task-boundary agent force: ${taskBoundaryDecision.taskType}/${taskBoundaryDecision.taskMode}`);
      } else {
        shouldRunAgentConversation = true;
        shouldKeepSelectedModel = false;
        chatApiLogger.info(`[Smart Auto Mode] 🧭 Force agent conversation due to task boundary: ${taskBoundaryDecision.taskType}/${taskBoundaryDecision.taskMode}`);
      }
    }

    if (taskBoundaryOverridesLegacyWorkflow && shouldKeepSelectedModel) {
      shouldKeepSelectedModel = false;
      chatApiLogger.info(`[Smart Auto Mode] 🧼 Release selected-model lock due to task boundary override: ${taskBoundaryDecision.taskType}`);
    }

    if (resolvedConversationAction.forceAgentConversation && !shouldRunAgentConversation) {
      if (shouldRespectDirectComposerMode) {
        chatApiLogger.info(`[Smart Auto Mode] ⛳ Respect direct composer mode (${composerMode}), skip legacy workflow force: ${resolvedConversationAction.kind}`);
      } else if (taskBoundaryOverridesLegacyWorkflow) {
        chatApiLogger.info(`[Smart Auto Mode] 🪫 Ignore legacy workflow follow-up due to task boundary override: ${resolvedConversationAction.kind} -> ${taskBoundaryDecision.taskType}`);
      } else {
        shouldRunAgentConversation = true;
        shouldKeepSelectedModel = resolvedConversationAction.shouldKeepSelectedModel;
        if (resolvedConversationAction.kind === "grid_confirmation_followup" && pendingGridConfirmation) {
          chatApiLogger.info(`[Smart Auto Mode] 🧩 Force agent conversation due to pending grid confirmation: ${pendingGridConfirmation.label}`);
        } else if (
          resolvedConversationAction.kind === "active_storyboard_followup" &&
          activeStoryboardTaskForChat?.task?.id
        ) {
          chatApiLogger.info(`[Smart Auto Mode] 🔐 Force agent conversation due to active storyboard task: ${activeStoryboardTaskForChat.task.id}`);
        } else if (resolvedConversationAction.kind === "image_generation_followup") {
          chatApiLogger.info("[Smart Auto Mode] 🪄 Force agent conversation due to image generation follow-up workflow");
        } else if (resolvedConversationAction.kind === "image_edit_followup") {
          chatApiLogger.info("[Smart Auto Mode] 🖼️ Force agent conversation due to image edit follow-up workflow");
        }
      }
    }

    const shouldFastTrackPromptOnly =
      shouldRunAgentConversation && taskBoundaryDecision.taskType === "prompt_only";
    if (shouldFastTrackPromptOnly) {
      if (!requestResolvedMediaInput) {
        requestResolvedMediaInput = resolveChatMediaInput({
          messageParts: message.parts as any[],
          historyMessages: [],
          contextPayload: effectiveContextPayload,
          requestOrigin,
          maxImages: 4,
        });
      }

      if (!requestTargetResolution) {
        requestTargetResolution = resolveTargetAssets({
          text: requestTextContent,
          mediaInput: requestResolvedMediaInput,
          contextPayload: effectiveContextPayload,
          workingState: effectiveWorkingState || undefined,
        });
      }

      smartAutoDetectedIntent = "vision";
      smartAutoNeedsClarification = false;
      smartAutoFriendlyMessage =
        "收到，我先分析这张图并整理可直接使用的提示词，不会直接生图。";
      chatApiLogger.info("[Smart Auto Mode] ✍️ Fast-path prompt-only request, skip heavy auto-agent workflow");
    }

    // ========== Smart Auto Mode Logic ==========
    if (shouldRunAgentConversation && !shouldFastTrackPromptOnly) {
      chatApiLogger.info("[Smart Auto Mode] 🚀 Starting intelligent analysis...");
      let autoTextForFallback = "";
      let autoFromHistoryForFallback = false;
      let autoCurrentImageUrlsForFallback: string[] = [];
      let confirmedPromptForGeneration: string | undefined;
      let forcePromptDrivenImageGeneration = false;
      let shouldPreferArbitratedFriendlyMessage = false;
      const smartAutoInputText =
        resolvedConversationAction.effectiveInputText || requestTextContent;
      
      try {
        // 🆕 首先获取历史消息（在 Smart Auto Mode 内部单独获取，避免依赖后面的 messagesFromDb）
        const loadedHistoryMessages = await getMessagesByChatId({ id });
        smartAutoHistoryMessagesFromDb = pruneTaskBoundaryHistoryMessages({
          decision: taskBoundaryDecision,
          messages: loadedHistoryMessages,
          purpose: "model",
          hasCurrentImageInput: hasImageInputForConversationAction,
        });
        smartAutoMediaHistoryMessagesFromDb = pruneTaskBoundaryHistoryMessages({
          decision: taskBoundaryDecision,
          messages: loadedHistoryMessages,
          purpose: "media",
          hasCurrentImageInput: hasImageInputForConversationAction,
        });
        chatApiLogger.info("[Smart Auto Mode] Loaded", loadedHistoryMessages.length, "messages from DB");
        chatApiLogger.info("[Smart Auto Mode] Pruned history:", {
          modelMessages: smartAutoHistoryMessagesFromDb.length,
          mediaMessages: smartAutoMediaHistoryMessagesFromDb.length,
          taskType: taskBoundaryDecision.taskType,
          taskMode: taskBoundaryDecision.taskMode,
        });

        autoTextForFallback = smartAutoInputText;
        if (!requestWorkingState && !shouldIsolateDirectComposerContext) {
          requestWorkingState = await getConversationWorkingStateByChatId({
            chatId: id,
          });
        }
        confirmedPromptForGeneration = confirmedPromptForConversationState;
        const isPromptCarryForwardExecution =
          resolvedConversationAction.kind === "prompt_carry_forward";
        forcePromptDrivenImageGeneration =
          resolvedConversationAction.usePromptCarryForward &&
          Boolean(confirmedPromptForGeneration);
        if (!requestResolvedMediaInput) {
          requestResolvedMediaInput = resolveChatMediaInput({
            messageParts: message.parts as any[],
            historyMessages: smartAutoMediaHistoryMessagesFromDb,
            contextPayload: effectiveContextPayload,
            requestOrigin,
            maxImages: 4,
          });
        }
        if (!requestTargetResolution) {
          requestTargetResolution = resolveTargetAssets({
            text: requestTextContent,
            mediaInput: requestResolvedMediaInput,
            contextPayload: effectiveContextPayload,
            workingState: effectiveWorkingState || undefined,
          });
        }

        const hasSelectedImageHint =
          Boolean(effectiveContextPayload?.selectedNodeIds?.length) ||
          /用户已选中\s*\d+\s*张图片/.test(effectiveAutoContextText);
        const hasExplicitTargetHint =
          requestTargetResolution.resolutionMode === "text_reference" ||
          /第[一二三四五六七八九十\d]+张|左边|左侧|左上|左下|右边|右侧|右上|右下|上面|上方|下面|下方|中间|居中|中央|选中/.test(requestTextContent);
        const hasActionableEditIntent = /改|调整|优化|换|替换|去掉|抠|重绘|增强|修|处理|按照|按|保留|统一|色差|背景|清晰|风格/.test(
          requestTextContent
        );

        const currentMessageImageInputs = requestResolvedMediaInput.currentMessageImageUrls.slice(0, 4);
        let imageUrls =
          requestTargetResolution.targetImageUrls.length > 0
            ? requestTargetResolution.targetImageUrls.slice(0, 4)
            : requestResolvedMediaInput.resolvedImageUrls.slice(0, 4);
        let hasImage = imageUrls.length > 0;
        autoCurrentImageUrlsForFallback =
          currentMessageImageInputs.length > 0 ? currentMessageImageInputs.slice() : imageUrls.slice();
        smartAutoHistoryImages =
          currentMessageImageInputs.length === 0 ? imageUrls.slice(0, 4) : [];
        autoFromHistoryForFallback =
          currentMessageImageInputs.length === 0 && imageUrls.length > 0;

        if (forcePromptDrivenImageGeneration) {
          imageUrls = [];
          hasImage = false;
          autoCurrentImageUrlsForFallback = [];
          smartAutoHistoryImages = [];
          autoFromHistoryForFallback = false;
          autoTextForFallback = confirmedPromptForGeneration || requestTextContent;
          smartAutoOptimizedPrompt = confirmedPromptForGeneration;
          chatApiLogger.info("[Smart Auto Mode] 🎯 Using confirmed prompt-only result for image generation");
        }

        chatApiLogger.info("[Smart Auto Mode] Input:", {
          textContent: requestTextContent.substring(0, 100),
          hasImage,
          imageCount: imageUrls.length,
          fromHistory: smartAutoHistoryImages.length > 0,
          resolutionMode: requestTargetResolution.resolutionMode,
          resolutionConfidence: requestTargetResolution.confidence,
        });

        // 🆕 从历史消息中提取对话文本（用于上下文理解）
        const historyMessages: { role: "user" | "assistant"; content: string }[] = [];
        for (const msg of smartAutoHistoryMessagesFromDb.slice(-10)) {  // 最多取最近10条
          const parts = msg.parts as any[];
          if (parts && parts.length > 0) {
            // 提取文本内容
            const textParts = parts.filter((p: any) => p.type === 'text');
            const content = textParts.map((p: any) => p.text || '').join(' ').trim();
            if (content) {
              historyMessages.push({
                role: msg.role as "user" | "assistant",
                content: content.substring(0, 300),  // 限制长度
              });
            }
          }
        }
        chatApiLogger.info("[Smart Auto Mode] History context:", historyMessages.length, "messages");

        // 2. 使用 LangGraph 驱动的自动模式工作流
        const { runAutoAgentGraph } = await import("@/lib/ai/auto-agent-graph");
        const autoGraphTimeoutMs = getBudgetedTimeout({
          startedAt: requestStartedAt,
          preferredMs: SMART_AUTO_GRAPH_TIMEOUT_MS,
          minimumMs: 8_000,
        });
        if (!autoGraphTimeoutMs) {
          throw new OperationTimeoutError(
            "runAutoAgentGraph.preResponseBudget",
            CHAT_PRE_RESPONSE_SOFT_TIMEOUT_MS
          );
        }
        const composedConversationState = composeConversationStateProtocol({
          bootstrap: conversationStateBootstrap,
          autoContextText: effectiveAutoContextText || undefined,
          resolvedMediaInput: requestResolvedMediaInput,
          targetResolution: requestTargetResolution,
        });
        chatApiLogger.info("[ConversationStateProtocol] Composed:", {
          workflowType: composedConversationState.threadState.workflowState?.type || null,
          workflowStatus: composedConversationState.threadState.workflowState?.status || null,
          memoryHintsCount: composedConversationState.threadState.memoryHints.length,
          contextSummaryPreview: composedConversationState.threadState.contextSummary?.slice(0, 180),
        });
        pendingProtocolDebugEvents.push({
          phase: "composed",
          payload: {
            workflowState: composedConversationState.threadState.workflowState,
            memoryHints: composedConversationState.threadState.memoryHints,
            contextSummary: composedConversationState.threadState.contextSummary,
          },
        });
        const autoGraphResult = await withOperationTimeout(
          runAutoAgentGraph({
            text: smartAutoInputText,
            hasImage,
            imageUrls,
            assetIds: Array.from(
                new Set([
                  ...extractMessageImageAssetIds(message.parts as any[]),
                  ...((effectiveContextPayload?.selectedAssetIds || []).filter(Boolean) as string[]),
                ]),
              ),
            imageFromHistory: smartAutoHistoryImages.length > 0,
            targetResolutionMode: requestTargetResolution.resolutionMode,
            mediaSource: requestResolvedMediaInput.source,
            hasCanvasSelection:
              Boolean(effectiveContextPayload?.selectedNodeIds?.length) ||
              requestResolvedMediaInput.selectedImageUrls.length > 0,
            selectedImageCount: requestResolvedMediaInput.selectedImageUrls.length,
            historyImageCount:
              requestResolvedMediaInput.historyAssistantImageUrls.length +
              requestResolvedMediaInput.historyUserImageUrls.length,
            currentUploadImageCount: requestResolvedMediaInput.currentMessageImageUrls.length,
            historyMessages,
            context:
              composedConversationState.composedConversationMemory.contextSummary ||
              effectiveAutoContextText ||
              undefined,
            preferredModelId: preferredAgentModelId,
            threadState: composedConversationState.threadState,
          }),
          "runAutoAgentGraph",
          autoGraphTimeoutMs,
        );

        const requestedStoryboardGrid = detectRequestedStoryboardGrid(
          pendingGridConfirmation && isGridConfirmationReply(requestTextContent)
            ? pendingGridConfirmation.originalPrompt
            : requestTextContent
        );
        if (requestedStoryboardGrid) {
          storyboardPreferenceMemory = buildStoryboardPreferenceMemoryUpdate({
            existing: storyboardPreferenceMemory,
            preferredGridType: requestedStoryboardGrid.gridType,
            preferredShotCount: requestedStoryboardGrid.shotCount,
            prefersConfirmation: true,
            lastUsedGridType: requestedStoryboardGrid.gridType,
            lastUsedShotCount: requestedStoryboardGrid.shotCount,
          });
        }

        smartAutoPlan = autoGraphResult.plan;
        smartAutoExecution = autoGraphResult.execution;

        if (autoGraphResult.workflowDecision) {
          smartAutoWorkflowDecision = autoGraphResult.workflowDecision;
          chatApiLogger.info("[Smart Auto Mode] Workflow decision:", {
            action: autoGraphResult.workflowDecision.action,
            intent: autoGraphResult.workflowDecision.confirmationIntent,
            workflowId: autoGraphResult.workflowDecision.workflowId,
            workflowType: autoGraphResult.workflowDecision.workflowType,
            nextWorkflowStatus: autoGraphResult.workflowDecision.nextWorkflowStatus,
            allowWorkflowExecution: autoGraphResult.workflowDecision.allowWorkflowExecution,
          });

          if (
            autoGraphResult.workflowDecision.workflowType === "storyboard_video" &&
            autoGraphResult.workflowDecision.workflowId
          ) {
            const storyboardTaskId = autoGraphResult.workflowDecision.workflowId;
            try {
              switch (autoGraphResult.workflowDecision.action) {
                case "awaiting_confirmation":
                  await markVideoStoryboardAwaitingConfirmation({
                    taskId: storyboardTaskId,
                  });
                  break;
                case "confirmed":
                  await markVideoStoryboardConfirmed({
                    taskId: storyboardTaskId,
                    messageId: message.id,
                  });
                  break;
                case "revision_requested":
                  await markVideoStoryboardDraftForRevision({
                    taskId: storyboardTaskId,
                  });
                  break;
                case "cancel_requested":
                  await cancelVideoStoryboardTaskByUser({
                    taskId: storyboardTaskId,
                    error: "user_cancelled_via_chat",
                  });
                  break;
                case "pass":
                default:
                  break;
              }
            } catch (workflowPersistError) {
              chatApiLogger.warn("[Smart Auto Mode] Failed to persist storyboard workflow decision:", workflowPersistError);
            }
          }
        }

        if (forcePromptDrivenImageGeneration && confirmedPromptForGeneration) {
          smartAutoDetectedIntent = "image_gen";
          smartAutoOptimizedPrompt = confirmedPromptForGeneration;
          smartAutoExecution = {
            mode: "generate_image",
            routeIntent: "image_gen",
            routeSubIntent: undefined,
            targetSource: "none",
            preferredCapability: "generate_image",
            shouldUseStructuredReply: true,
            shouldOptimizePrompt: true,
            shouldApplyImagePipeline: true,
            shouldApplyVideoPipeline: false,
            shouldStayConversational: false,
            shouldPublishToCanvas: false,
            toolCalls: [],
            availableTools: [],
          };
          smartAutoFriendlyMessage =
            smartAutoFriendlyMessage ||
            (isPromptCarryForwardExecution
              ? "收到，我会使用上一轮优化后的提示词，结合你这轮图片继续执行。"
              : "收到，我会按你刚确认的提示词直接生图。");
        }

        if (smartAutoPlan) {
          chatApiLogger.info("[Smart Auto Mode] Plan result:", {
            goal: smartAutoPlan.goal,
            nextAction: smartAutoPlan.nextAction,
            intent: smartAutoPlan.intent,
            targetSource: smartAutoPlan.targetSource,
            preferredCapability: smartAutoPlan.preferredCapability,
            confidence: smartAutoPlan.confidence,
            toolCalls: smartAutoPlan.toolCalls?.map((tool) => tool.name) || [],
          });
        }

        if (autoGraphResult.analysis) {
          chatApiLogger.info("[Smart Auto Mode] Analysis result:", {
            intent: autoGraphResult.analysis.intent,
            subIntent: autoGraphResult.analysis.subIntent,
            confidence: autoGraphResult.analysis.confidence,
            needsClarification: autoGraphResult.analysis.needsClarification,
          });

          const arbitratedIntent = arbitrateAgentIntent({
            text: requestTextContent,
            hasImage,
            hasHistoryImage: smartAutoHistoryImages.length > 0,
            actionResolution: resolvedConversationAction,
            taskBoundaryDecision,
            analysis: autoGraphResult.analysis,
            execution: smartAutoExecution,
            targetSource: requestTargetResolution.resolutionMode,
          });
          if (arbitratedIntent.overridden) {
            chatApiLogger.info("[IntentArbiter] Override auto-agent intent:", {
              fromIntent: autoGraphResult.analysis.intent,
              fromMode: autoGraphResult.execution?.mode,
              toIntent: arbitratedIntent.analysis.intent,
              toMode: arbitratedIntent.execution.mode,
              reason: arbitratedIntent.reason,
            });
          }

          smartAutoExecution = arbitratedIntent.execution as AgentPreparedExecution;
          smartAutoDetectedIntent = arbitratedIntent.analysis.intent;
          smartAutoNeedsClarification =
            Boolean(arbitratedIntent.analysis.needsClarification) ||
            (!arbitratedIntent.overridden && smartAutoPlan?.nextAction === "clarify");
          smartAutoClarificationQuestion = arbitratedIntent.analysis.clarifyingQuestions?.[0];
          if (arbitratedIntent.friendlyMessage) {
            smartAutoFriendlyMessage = arbitratedIntent.friendlyMessage;
            shouldPreferArbitratedFriendlyMessage = true;
          }

          const targetExecutionOverride = resolveTargetExecutionOverride({
            hasImage,
            hasSelectedImageHint,
            hasExplicitTargetHint,
            hasActionableEditIntent,
            executionMode: smartAutoExecution?.mode,
            friendlyMessage: smartAutoFriendlyMessage,
            optimizedPrompt: smartAutoOptimizedPrompt,
            requestText: requestTextContent,
          });

          if (
            smartAutoNeedsClarification &&
            targetExecutionOverride.shouldBypassClarification
          ) {
            smartAutoNeedsClarification = false;
            smartAutoClarificationQuestion = undefined;
            smartAutoOptimizedPrompt = targetExecutionOverride.nextOptimizedPrompt;
            smartAutoFriendlyMessage = targetExecutionOverride.nextFriendlyMessage;
            chatApiLogger.info("[Smart Auto Mode] ✅ Skip clarification due to explicit target/selection context");
          }
        }

        const requestedGrid =
          !pendingGridConfirmation || smartAutoInputText === requestTextContent
            ? detectRequestedStoryboardGrid(requestTextContent)
            : pendingGridConfirmation;
        const gridConfirmationResolution = resolveGridConfirmationRequest({
          requestedGrid,
          hasActiveStoryboardTask: Boolean(activeStoryboardTaskForChat?.task?.id),
          executionMode: smartAutoExecution?.mode,
          detectedIntent: smartAutoDetectedIntent,
          requestText: requestTextContent,
          effectiveInputText: smartAutoInputText,
        });
        if (gridConfirmationResolution.shouldRequestConfirmation) {
          shouldAskGridConfirmation = true;
          smartAutoNeedsClarification = true;
          smartAutoClarificationQuestion = gridConfirmationResolution.clarificationMessage;
          smartAutoFriendlyMessage = gridConfirmationResolution.clarificationMessage;
          pendingGridConfirmation = gridConfirmationResolution.pendingGridConfirmation;
          chatApiLogger.info("[Smart Auto Mode] 🧱 Require grid confirmation before generation:", {
            gridType: gridConfirmationResolution.pendingGridConfirmation?.gridType,
            shotCount: gridConfirmationResolution.pendingGridConfirmation?.shotCount,
          });
        }

        if (autoGraphResult.friendlyMessage && !shouldPreferArbitratedFriendlyMessage) {
          smartAutoFriendlyMessage = autoGraphResult.friendlyMessage;
          chatApiLogger.info("[Smart Auto Mode] 💬 Conversational reply:", smartAutoFriendlyMessage);
        }

        if (shouldAskGridConfirmation && smartAutoClarificationQuestion) {
          smartAutoFriendlyMessage = smartAutoClarificationQuestion;
        }

        if (
          !smartAutoNeedsClarification &&
          hasImage &&
          hasActionableEditIntent &&
          (hasSelectedImageHint || hasExplicitTargetHint) &&
          smartAutoFriendlyMessage &&
          (/[?？]$/.test(smartAutoFriendlyMessage.trim()) ||
            /哪一张|哪个|请先确认/.test(smartAutoFriendlyMessage))
        ) {
          smartAutoFriendlyMessage = "收到，我将按你指定的目标图直接执行。";
          chatApiLogger.info("[Smart Auto Mode] ✅ Replace clarification-like friendly reply");
        }

        const autoIntent = smartAutoDetectedIntent || autoGraphResult.analysis?.intent;
        const autoExecutionMode = smartAutoExecution?.mode;
        const isImageTask =
          autoExecutionMode === "generate_image" ||
          autoExecutionMode === "edit_image";
        const needsRicherAutoReply =
          !smartAutoNeedsClarification &&
          !smartAutoFriendlyMessage;

        if (needsRicherAutoReply) {
          if (isImageTask) {
            smartAutoFriendlyMessage =
              autoGraphResult.analysis?.conversationalReply ||
              "我先分析你这轮图片里的主体、风格和构图，再给你执行方案。";
          } else if (autoIntent === "vision") {
            smartAutoFriendlyMessage =
              autoGraphResult.analysis?.conversationalReply ||
              "收到，我先看图分析，再直接回答你。";
          } else if (autoIntent === "chat") {
            smartAutoFriendlyMessage =
              autoGraphResult.analysis?.conversationalReply ||
              "收到，我们先继续聊你的这个需求。";
          } else {
            smartAutoFriendlyMessage =
              smartAutoExecution?.shouldUseStructuredReply
                ? buildAutoModeFallbackMessage({
                    text: autoTextForFallback,
                    hasImage,
                    fromHistory: smartAutoHistoryImages.length > 0,
                  })
                : "收到，我先理解你的当前目标，再继续处理。";
          }
          chatApiLogger.info("[Smart Auto Mode] 🧩 Filled missing conversational reply");
        }

        if (autoGraphResult.optimizedPrompt) {
          smartAutoOptimizedPrompt = autoGraphResult.optimizedPrompt;
          chatApiLogger.info("[Smart Auto Mode] ✨ Prompt optimized (LLM):", {
            original: requestTextContent.substring(0, 50),
            optimized: autoGraphResult.optimizedPrompt.substring(0, 100),
          });
        }
        if (autoGraphResult.videoPlan) {
          smartAutoVideoPlan = autoGraphResult.videoPlan;
          smartAutoRecommendedVideoParams = autoGraphResult.videoPlan.recommendedVideoParams;
          if (!smartAutoOptimizedPrompt && autoGraphResult.videoPlan.finalPrompt?.trim()) {
            smartAutoOptimizedPrompt = autoGraphResult.videoPlan.finalPrompt.trim();
            smartAutoPromptFromVideoPlan = true;
          }
          chatApiLogger.info("[Smart Auto Mode] 🎬 Agent video plan ready:", {
            hasScript: Boolean(autoGraphResult.videoPlan.script),
            storyboardCount: autoGraphResult.videoPlan.storyboard?.length || 0,
            hasFinalPrompt: Boolean(autoGraphResult.videoPlan.finalPrompt),
            recommendedVideoParams: smartAutoRecommendedVideoParams,
          });
        }
        if (autoGraphResult.recommendedImageParams) {
          smartAutoRecommendedImageParams = autoGraphResult.recommendedImageParams;
          chatApiLogger.info("[Smart Auto Mode] 🎛️ Agent recommended image params:", smartAutoRecommendedImageParams);
        }

        const shouldForceConversationalRouteForVisualModel =
          shouldKeepSelectedModel &&
          requestedModelIsFixedVisual &&
          !requestedModelIsConversationMultimodal &&
          Boolean(smartAutoExecution?.shouldStayConversational);

        if (autoGraphResult.route && (!shouldKeepSelectedModel || shouldForceConversationalRouteForVisualModel)) {
          const routeIsVideo = isVideoProviderType(autoGraphResult.route.providerType, {
            modelId: autoGraphResult.route.modelId,
          });
          if (routeIsVideo && !allowAgentVideoGeneration) {
            const fallbackIntent: "image_edit" | "image_gen" = hasImage ? "image_edit" : "image_gen";
            smartAutoDetectedIntent = fallbackIntent;
            smartAutoExecution = smartAutoExecution
              ? {
                  ...smartAutoExecution,
                  mode: hasImage ? "edit_image" : "generate_image",
                  routeIntent: fallbackIntent,
                  shouldApplyImagePipeline: true,
                  shouldApplyVideoPipeline: false,
                  shouldOptimizePrompt: true,
                  shouldStayConversational: false,
                  shouldUseStructuredReply: true,
                }
              : smartAutoExecution;
            smartAutoVideoPlan = undefined;
            smartAutoRecommendedVideoParams = undefined;
            if (smartAutoPromptFromVideoPlan) {
              smartAutoOptimizedPrompt = requestTextContent.trim() || undefined;
              smartAutoPromptFromVideoPlan = false;
            }
            smartAutoFriendlyMessage =
              smartAutoFriendlyMessage && !/视频/.test(smartAutoFriendlyMessage)
                ? smartAutoFriendlyMessage
                : "当前 Agent 默认按图片任务执行；如需生成视频，请先手动切换到“视频”模式。";
            chatApiLogger.info(`[Smart Auto Mode] 🚫 Blocked auto video route (${autoGraphResult.route.displayName}), fallback to ${fallbackIntent}`);
            try {
              const { routeToModel } = await import("@/lib/ai/model-router");
              const fallbackRoute = await routeToModel({
                intent: fallbackIntent,
                subIntent: autoGraphResult.analysis?.subIntent,
                hasImage,
              });
              if (!isVideoProviderType(fallbackRoute.providerType, { modelId: fallbackRoute.modelId })) {
                finalModelId = fallbackRoute.id;
                chatApiLogger.info(`[Smart Auto Mode] ✅ Fallback routed to: ${fallbackRoute.displayName} (${fallbackRoute.reason})`);
              } else {
                chatApiLogger.warn(`[Smart Auto Mode] ⚠️ Fallback route still video (${fallbackRoute.displayName}), keep previous model`);
              }
            } catch (fallbackRouteError) {
              chatApiLogger.error("[Smart Auto Mode] Failed to resolve non-video fallback route:", fallbackRouteError);
            }
          } else {
            finalModelId = autoGraphResult.route.id;
            chatApiLogger.info("console_log", shouldForceConversationalRouteForVisualModel
                ? `[Smart Auto Mode] ✅ Switched visual model to conversational route: ${autoGraphResult.route.displayName} (${autoGraphResult.route.reason})`
                : `[Smart Auto Mode] ✅ Routed to: ${autoGraphResult.route.displayName} (${autoGraphResult.route.reason})`);
          }
        } else if (autoGraphResult.route && shouldKeepSelectedModel) {
          finalModelId = requestedModelId;
          chatApiLogger.info("[Smart Auto Mode] 🔒 Keep user-selected model, skip routing override");
        }

      } catch (autoError) {
        // 智能分析失败时，回退到简单逻辑
        chatApiLogger.error("[Smart Auto Mode] ❌ Error, falling back:", autoError);
        const isAutoTimeout = autoError instanceof OperationTimeoutError;
        if (isAutoTimeout) {
          chatApiLogger.warn(`[Smart Auto Mode] ⏱️ Auto-agent timed out or exceeded pre-response budget (${CHAT_PRE_RESPONSE_SOFT_TIMEOUT_MS}ms), using local fallback`);
        }
        try {
          const { analyzeIntent } = await import("@/lib/ai/smart-analyzer");
          const rescueImageUrls =
            autoCurrentImageUrlsForFallback.length > 0
              ? autoCurrentImageUrlsForFallback
              : smartAutoHistoryImages;
          const rescueHasImage = rescueImageUrls.length > 0;
          const rescueFromHistory =
            rescueHasImage &&
            autoCurrentImageUrlsForFallback.length === 0 &&
            smartAutoHistoryImages.length > 0;
          const rescueAssetIds = Array.from(
            new Set([
              ...extractMessageImageAssetIds(message.parts as any[]),
              ...((effectiveContextPayload?.selectedAssetIds || []).filter(Boolean) as string[]),
            ]),
          );
          const rescueTimeoutMs = getBudgetedTimeout({
            startedAt: requestStartedAt,
            preferredMs: SMART_AUTO_FALLBACK_TIMEOUT_MS,
            minimumMs: 5_000,
          });
          if (rescueTimeoutMs) {
            const rescueAnalysis = await withOperationTimeout(
              analyzeIntent({
                text: autoTextForFallback,
                hasImage: rescueHasImage,
                imageUrls: rescueImageUrls,
                assetIds: rescueAssetIds,
                imageFromHistory: rescueFromHistory || autoFromHistoryForFallback,
                historyMessages: [],
                context: undefined,
                preferredModelId: preferredAgentModelId,
              }),
              "fallbackAnalyzeIntent",
              rescueTimeoutMs,
            );
            smartAutoDetectedIntent = rescueAnalysis.intent;
            const arbitratedIntent = arbitrateAgentIntent({
              text: autoTextForFallback,
              hasImage: rescueHasImage,
              hasHistoryImage: rescueFromHistory || autoFromHistoryForFallback,
              actionResolution: resolvedConversationAction,
              taskBoundaryDecision,
              analysis: rescueAnalysis,
              execution: undefined,
              targetSource: requestTargetResolution?.resolutionMode || "none",
            });
            if (arbitratedIntent.overridden) {
              chatApiLogger.info("[IntentArbiter] Override rescue intent:", {
                fromIntent: rescueAnalysis.intent,
                toIntent: arbitratedIntent.analysis.intent,
                toMode: arbitratedIntent.execution.mode,
                reason: arbitratedIntent.reason,
              });
            }
            smartAutoDetectedIntent = arbitratedIntent.analysis.intent;
            smartAutoNeedsClarification = Boolean(arbitratedIntent.analysis.needsClarification);
            smartAutoClarificationQuestion = arbitratedIntent.analysis.clarifyingQuestions?.[0];
            smartAutoExecution = arbitratedIntent.execution as AgentPreparedExecution;
            if (arbitratedIntent.friendlyMessage || rescueAnalysis.conversationalReply?.trim()) {
              smartAutoFriendlyMessage = (
                arbitratedIntent.friendlyMessage ||
                rescueAnalysis.conversationalReply ||
                ""
              ).trim();
            }
          } else {
            chatApiLogger.warn("[Smart Auto Mode] Skip rescue analysis due to pre-response budget");
          }
        } catch (rescueError) {
          chatApiLogger.error("[Smart Auto Mode] Rescue analysis failed:", rescueError);
          try {
            const { fallbackKeywordAnalysis } = await import("@/lib/ai/smart-analyzer");
            const keywordFallback = fallbackKeywordAnalysis(
              autoTextForFallback,
              autoCurrentImageUrlsForFallback.length > 0 || smartAutoHistoryImages.length > 0,
            );
            const arbitratedIntent = arbitrateAgentIntent({
              text: autoTextForFallback,
              hasImage:
                autoCurrentImageUrlsForFallback.length > 0 || smartAutoHistoryImages.length > 0,
              hasHistoryImage: smartAutoHistoryImages.length > 0 || autoFromHistoryForFallback,
              actionResolution: resolvedConversationAction,
              taskBoundaryDecision,
              analysis: keywordFallback,
              execution: undefined,
              targetSource: requestTargetResolution?.resolutionMode || "none",
            });
            if (arbitratedIntent.overridden) {
              chatApiLogger.info("[IntentArbiter] Override keyword-fallback intent:", {
                fromIntent: keywordFallback.intent,
                toIntent: arbitratedIntent.analysis.intent,
                toMode: arbitratedIntent.execution.mode,
                reason: arbitratedIntent.reason,
              });
            }
            smartAutoDetectedIntent = arbitratedIntent.analysis.intent;
            smartAutoNeedsClarification = Boolean(arbitratedIntent.analysis.needsClarification);
            smartAutoClarificationQuestion = arbitratedIntent.analysis.clarifyingQuestions?.[0];
            smartAutoExecution = arbitratedIntent.execution as AgentPreparedExecution;
            if (arbitratedIntent.friendlyMessage || keywordFallback.conversationalReply?.trim()) {
              smartAutoFriendlyMessage = (
                arbitratedIntent.friendlyMessage ||
                keywordFallback.conversationalReply ||
                ""
              ).trim();
              chatApiLogger.warn("[Smart Auto Mode] Applied keyword fallback after rescue failure");
            }
          } catch (keywordFallbackError) {
            chatApiLogger.warn("[Smart Auto Mode] Keyword fallback after rescue failure also failed:", keywordFallbackError);
          }
        }
        
        if (
          !smartAutoOptimizedPrompt &&
          smartAutoExecution?.shouldOptimizePrompt &&
          (smartAutoDetectedIntent === "image_edit" || smartAutoDetectedIntent === "image_gen")
        ) {
          try {
            const { optimizePrompt } = await import("@/lib/ai/prompt-optimizer");
            const optimizedFallback = optimizePrompt({
              originalPrompt: autoTextForFallback,
              intent: smartAutoDetectedIntent,
              subIntent: smartAutoExecution.routeSubIntent,
            });
            if (optimizedFallback.optimizedPrompt?.trim()) {
              smartAutoOptimizedPrompt = optimizedFallback.optimizedPrompt.trim();
              chatApiLogger.info("[Smart Auto Mode] ✨ Prompt optimized (fallback heuristic):", {
                original: autoTextForFallback.substring(0, 80),
                optimized: smartAutoOptimizedPrompt.substring(0, 140),
                intent: smartAutoDetectedIntent,
                subIntent: smartAutoExecution.routeSubIntent || null,
              });
            }
            if (!smartAutoRecommendedImageParams && optimizedFallback.recommendedImageParams) {
              smartAutoRecommendedImageParams = optimizedFallback.recommendedImageParams;
            }
          } catch (fallbackOptimizeError) {
            chatApiLogger.warn("[Smart Auto Mode] Fallback prompt optimization failed:", fallbackOptimizeError);
          }
        }

        const allModels = await getEnabledAiModelsWithProvider();
        const hasImage =
          autoCurrentImageUrlsForFallback.length > 0 || smartAutoHistoryImages.length > 0;
        let fallbackVisualSummary: string | undefined;

        if (isAutoTimeout && hasImage) {
          try {
            const currentImageUrls =
              autoCurrentImageUrlsForFallback.length > 0
                ? autoCurrentImageUrlsForFallback
                : collectImageInputsFromMessageParts(message.parts as any[], requestOrigin);
            const summaryImageUrls =
              currentImageUrls.length > 0 ? currentImageUrls : smartAutoHistoryImages;

            if (summaryImageUrls.length > 0) {
              const { summarizeImageForExecutionReport } = await import("@/lib/ai/smart-analyzer");
              const summaryAssetIds = Array.from(
                new Set([
                  ...extractMessageImageAssetIds(message.parts as any[]),
                  ...((effectiveContextPayload?.selectedAssetIds || []).filter(Boolean) as string[]),
                ]),
              );
              const fallbackSummaryTimeoutMs = getBudgetedTimeout({
                startedAt: requestStartedAt,
                preferredMs: SMART_AUTO_IMAGE_SUMMARY_TIMEOUT_MS,
                minimumMs: 5_000,
              });
              if (fallbackSummaryTimeoutMs) {
                const summary = await withOperationTimeout(
                  summarizeImageForExecutionReport({
                    text: autoTextForFallback,
                    imageUrls: summaryImageUrls,
                    context: effectiveAutoContextText || undefined,
                    preferredModelId: preferredAgentModelId,
                    assetIds: summaryAssetIds,
                    timeoutMs: fallbackSummaryTimeoutMs,
                  }),
                  "fallbackVisualSummary",
                  fallbackSummaryTimeoutMs,
                );
                if (summary?.trim()) {
                  fallbackVisualSummary = summary.trim();
                }
              } else {
                chatApiLogger.warn("[Smart Auto Mode] Skip fallback visual summary due to pre-response budget");
              }
            }
          } catch (summaryError) {
            chatApiLogger.warn("[Smart Auto Mode] Fallback visual summary failed:", summaryError);
          }
        }
        
        // 回退路由：优先按分析出的意图选模型，避免“有图就生图”
        let bestModel = null;
        try {
          const fallbackIntent =
            smartAutoDetectedIntent || (hasImage ? "vision" : "chat");
          const { routeToModel } = await import("@/lib/ai/model-router");
          const fallbackRoute = await routeToModel({
            intent: fallbackIntent,
            subIntent: smartAutoExecution?.routeSubIntent,
            hasImage,
          });
          bestModel = allModels.find(
            (item) => item.model.id === fallbackRoute.id || item.model.modelId === fallbackRoute.modelId,
          ) || null;
          if (bestModel) {
            chatApiLogger.info(`[Smart Auto Mode] Fallback routed by intent: ${fallbackRoute.displayName} (${fallbackRoute.reason})`);
          }
        } catch (fallbackRouteError) {
          chatApiLogger.warn("[Smart Auto Mode] Fallback routeByIntent failed, use local heuristic:", fallbackRouteError);
        }

        if (!bestModel && hasImage) {
          bestModel = allModels.find(
            (m) =>
              m.model.supportsImageGen &&
              !m.model.isSubModel &&
              !isVideoProviderType(m.provider?.type, m.model),
          );
          if (isAutoTimeout) {
              smartAutoFriendlyMessage = buildAutoModeFallbackMessage({
                text: autoTextForFallback,
                hasImage: true,
                fromHistory: autoFromHistoryForFallback || smartAutoHistoryImages.length > 0,
                imageSummary: fallbackVisualSummary,
              });
            } else {
              smartAutoFriendlyMessage =
                smartAutoFriendlyMessage ||
                buildAutoModeFallbackMessage({
                  text: autoTextForFallback,
                  hasImage: true,
                  fromHistory: autoFromHistoryForFallback || smartAutoHistoryImages.length > 0,
                  imageSummary: fallbackVisualSummary,
                });
            }
          } else {
            smartAutoFriendlyMessage = smartAutoFriendlyMessage || buildAutoModeFallbackMessage({
              text: autoTextForFallback,
            hasImage: false,
            fromHistory: false,
          });
        }
        if (!bestModel) {
          bestModel = allModels.find(
            (m) =>
              m.model.isDefault &&
              !m.model.isSubModel &&
              !isVideoProviderType(m.provider?.type, m.model),
          );
        }
        if (!bestModel && allModels.length > 0) {
          bestModel = allModels.find(
            (m) => !m.model.isSubModel && !isVideoProviderType(m.provider?.type, m.model),
          ) || allModels.find((m) => !m.model.isSubModel) || allModels[0];
        }
        
        if (shouldKeepSelectedModel) {
          finalModelId = requestedModelId;
          chatApiLogger.info("[Smart Auto Mode] 🔒 Keep user-selected model in fallback mode");
        } else if (bestModel) {
          finalModelId = bestModel.model.id;
          chatApiLogger.info(`[Smart Auto Mode] Fallback selected: ${bestModel.model.displayName}`);
        } else {
          return new ChatSDKError("bad_request:api", "No available models for auto mode").toResponse();
        }
      }
    }
    // ========== End Smart Auto Mode Logic ==========

    if (shouldRunAgentConversation && !allowAgentVideoGeneration) {
      const finalModelIsUuid =
        /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(finalModelId);
      let finalProviderType: string | undefined;
      let finalModelConfig: Awaited<ReturnType<typeof getAiModelById>> | null = null;

      if (finalModelIsUuid) {
        finalModelConfig = await getAiModelById({ id: finalModelId }).catch(() => null);
        if (finalModelConfig) {
          finalProviderType = (
            await getAiProviderById({ id: finalModelConfig.providerId }).catch(() => null)
          )?.type as string | undefined;
        }
      }

      if (isVideoProviderType(finalProviderType, finalModelConfig || undefined)) {
        const allModels = await getEnabledAiModelsWithProvider(false);
        const fallbackModel =
          allModels.find(
            (m) =>
              !m.model.isSubModel &&
              m.model.supportsImageGen &&
              !isVideoProviderType(m.provider?.type, m.model),
          ) ||
          allModels.find(
            (m) =>
              !m.model.isSubModel &&
              !isVideoProviderType(m.provider?.type, m.model),
          );

        if (fallbackModel) {
          const hasImageInput = message.parts.some((part: any) =>
            part?.type === "file" || part?.type === "image" || part?.type === "image_url"
          );
          smartAutoDetectedIntent = hasImageInput ? "image_edit" : "image_gen";
          smartAutoExecution = smartAutoExecution
            ? {
                ...smartAutoExecution,
                mode: hasImageInput ? "edit_image" : "generate_image",
                routeIntent: hasImageInput ? "image_edit" : "image_gen",
                shouldApplyImagePipeline: true,
                shouldApplyVideoPipeline: false,
                shouldOptimizePrompt: true,
                shouldStayConversational: false,
                shouldUseStructuredReply: true,
              }
            : smartAutoExecution;
          finalModelId = fallbackModel.model.id;
          smartAutoVideoPlan = undefined;
          smartAutoRecommendedVideoParams = undefined;
          chatApiLogger.info(`[Smart Auto Mode] 🚫 Safety override: replace video model (${finalProviderType}) with ${fallbackModel.model.displayName}`);
        }
      }
    }

    if (
      shouldRunAgentConversation &&
      !smartAutoNeedsClarification &&
      !smartAutoFriendlyMessage?.trim()
    ) {
      const latestUserText = message.parts
        .filter((part): part is { type: "text"; text: string } => part.type === "text")
        .map((part) => part.text)
        .join(" ");
      const hasCurrentImageInput = message.parts.some((part: any) =>
        part?.type === "file" || part?.type === "image" || part?.type === "image_url"
      );
      const hasHistoryImageInput = smartAutoHistoryImages.length > 0;
      smartAutoFriendlyMessage =
        smartAutoExecution?.shouldUseStructuredReply
          ? buildAutoModeFallbackMessage({
              text: latestUserText,
              hasImage: hasCurrentImageInput || hasHistoryImageInput,
              fromHistory: !hasCurrentImageInput && hasHistoryImageInput,
            })
          : "收到，我先理解你的当前目标，再继续处理。";
      chatApiLogger.info("[Smart Auto Mode] 🧩 Backfilled conversational reply with fallback");
    }

    if (
      shouldRunAgentConversation &&
      !smartAutoNeedsClarification &&
      smartAutoExecution?.shouldUseStructuredReply
    ) {
      const latestUserText = message.parts
        .filter((part): part is { type: "text"; text: string } => part.type === "text")
        .map((part) => part.text)
        .join(" ");
      const hasCurrentImageInput = message.parts.some((part: any) =>
        part?.type === "file" || part?.type === "image" || part?.type === "image_url"
      );
      const hasHistoryImageInput = smartAutoHistoryImages.length > 0;
      smartAutoFriendlyMessage = ensureStructuredAgentFriendlyMessage({
        message: smartAutoFriendlyMessage,
        text: latestUserText,
        hasImage: hasCurrentImageInput || hasHistoryImageInput,
        fromHistory: !hasCurrentImageInput && hasHistoryImageInput,
      });
    }

    const hasUserCustomImageParams = hasUserCustomizedImageParams(requestBody.imageParams);
    const hasUserCustomVideoParams = hasUserCustomizedVideoParams(requestBody.videoParams);
    const shouldApplyAgentImageParams =
      shouldRunAgentConversation &&
      !smartAutoNeedsClarification &&
      Boolean(smartAutoExecution?.shouldApplyImagePipeline);
    const shouldApplyAgentVideoParams =
      shouldRunAgentConversation &&
      !smartAutoNeedsClarification &&
      allowAgentVideoGeneration &&
      Boolean(smartAutoExecution?.shouldApplyVideoPipeline);
    const effectiveImageParams = shouldApplyAgentImageParams
      ? mergeImageParamsWithAgentRecommendation({
          incoming: requestBody.imageParams,
          recommended: smartAutoRecommendedImageParams,
          intent: smartAutoDetectedIntent,
          hasUserCustomSettings: hasUserCustomImageParams,
        })
      : requestBody.imageParams;
    const effectiveVideoParams = shouldApplyAgentVideoParams
      ? mergeVideoParamsWithAgentRecommendation({
          incoming: requestBody.videoParams,
          recommended: smartAutoRecommendedVideoParams,
          hasUserCustomSettings: hasUserCustomVideoParams,
        })
      : requestBody.videoParams;
    const defaultImageQualityParams = {
      aspectRatio: "auto",
      imageSize: smartAutoDetectedIntent === "image_edit" ? "4K" : "2K",
      imageCount: 1,
    } as const;

    if (shouldApplyAgentImageParams) {
      chatApiLogger.info("[Smart Auto Mode] 🎯 Effective image params:", {
        incoming: requestBody.imageParams,
        recommended: smartAutoRecommendedImageParams,
        merged: effectiveImageParams,
        hasUserCustomImageParams,
      });
    }
    if (shouldApplyAgentVideoParams) {
      chatApiLogger.info("[Smart Auto Mode] 🎯 Effective video params:", {
        incoming: requestBody.videoParams,
        recommended: smartAutoRecommendedVideoParams,
        merged: effectiveVideoParams,
        hasUserCustomVideoParams,
        hasVideoPlan: Boolean(smartAutoVideoPlan),
      });
    }

    if (
      shouldRunAgentConversation &&
      smartAutoFriendlyMessage &&
      smartAutoExecution?.shouldUseStructuredReply
    ) {
      smartAutoFriendlyMessage = sanitizeAgentOutputSettingsSection({
        message: smartAutoFriendlyMessage,
        userImageParams: requestBody.imageParams,
        hasUserCustomImageParams,
      });
      smartAutoFriendlyMessage = injectOptimizedPromptSection({
        message: smartAutoFriendlyMessage,
        originalText: requestTextContent,
        optimizedPrompt: smartAutoOptimizedPrompt,
      });
    }

    if (shouldRunAgentConversation) {
      const currentImageUrls = extractMessageImageUrls(message.parts as any[]);
      const summaryImageUrls =
        currentImageUrls.length > 0 ? currentImageUrls : smartAutoHistoryImages;
      const shouldRequireImageAnalysis = summaryImageUrls.length > 0;

      if (shouldRequireImageAnalysis) {
        try {
          const { summarizeImageForExecutionReport } = await import("@/lib/ai/smart-analyzer");
          const latestUserText = message.parts
            .filter((part): part is { type: "text"; text: string } => part.type === "text")
            .map((part) => part.text)
            .join(" ");
          const summaryAssetIds = Array.from(
                new Set([
                  ...extractMessageImageAssetIds(message.parts as any[]),
                  ...((effectiveContextPayload?.selectedAssetIds || []).filter(Boolean) as string[]),
                ]),
              );

          let summary: string | null = null;
          const summaryTimeoutMs = getBudgetedTimeout({
            startedAt: requestStartedAt,
            preferredMs: SMART_AUTO_IMAGE_SUMMARY_TIMEOUT_MS,
            minimumMs: 6_000,
          });
          if (summaryTimeoutMs) {
            summary = await withOperationTimeout(
              summarizeImageForExecutionReport({
                text: latestUserText,
                imageUrls: summaryImageUrls,
                context: effectiveAutoContextText || undefined,
                preferredModelId: preferredAgentModelId,
                assetIds: summaryAssetIds,
                timeoutMs: summaryTimeoutMs,
              }),
              "enrichImageAnalysisSummary",
              summaryTimeoutMs,
            );
          } else {
            chatApiLogger.warn("[Smart Auto Mode] Skip image summary enrichment due to pre-response budget");
          }

          if (summary?.trim() && smartAutoExecution?.shouldUseStructuredReply) {
            const baseMessage = ensureStructuredAgentFriendlyMessage({
              message: smartAutoFriendlyMessage,
              text: latestUserText,
              hasImage: true,
              fromHistory: currentImageUrls.length === 0 && summaryImageUrls.length > 0,
            });
            smartAutoFriendlyMessage = ensureImageAnalysisSummarySection(
              baseMessage ||
                buildAutoModeFallbackMessage({
                  text: latestUserText,
                  hasImage: true,
                  fromHistory: currentImageUrls.length === 0 && summaryImageUrls.length > 0,
                  imageSummary: summary.trim(),
                }),
              summary.trim(),
            );
            chatApiLogger.info("[Smart Auto Mode] ✅ Image analysis summary ready:", summary.trim().slice(0, 160));
          } else if (
            summary?.trim() &&
            !smartAutoExecution?.shouldUseStructuredReply &&
            !smartAutoFriendlyMessage
          ) {
            smartAutoFriendlyMessage = "收到，我会结合这张图的内容直接回答你。";
          } else if (smartAutoFriendlyMessage && shouldEnrichImageAnalysisText(smartAutoFriendlyMessage)) {
            chatApiLogger.warn("[Smart Auto Mode] ⚠️ Image summary unavailable, keep original analysis text");
          }
        } catch (enrichError) {
          chatApiLogger.warn("[Smart Auto Mode] Skip image analysis enrichment:", enrichError);
        }
      }
    }

    if (
      shouldRunAgentConversation &&
      smartAutoFriendlyMessage &&
      smartAutoExecution?.shouldUseStructuredReply
    ) {
      smartAutoFriendlyMessage = normalizeAgentReportForDisplay(smartAutoFriendlyMessage);
    }

    if (
      shouldRunAgentConversation &&
      !shouldKeepSelectedModel &&
      smartAutoExecution?.shouldStayConversational &&
      preferredAgentModelId
    ) {
      if (finalModelId !== preferredAgentModelId) {
        finalModelId = preferredAgentModelId;
        chatApiLogger.info(`[Smart Auto Mode] 🧠 Conversational reply follows agent default model: ${configuredAgentConversationModelId || preferredAgentModelId}`);
      }
    }

    if (shouldRunAgentConversation && smartAutoExecution?.shouldStayConversational) {
      const candidateReplyDescriptor = await resolveAgentModelSlotDescriptor(finalModelId).catch(
        () => null,
      );
      if (candidateReplyDescriptor) {
        agentModelSlots = upsertAgentModelSlot(agentModelSlots, "reply", {
          ...candidateReplyDescriptor,
          source: "candidate_reply_model",
          reason: "post_agent_routing",
          locked: shouldKeepSelectedModel,
        });

        const providerHealth = getProviderHealthSnapshot(candidateReplyDescriptor.providerKey);
        if (
          !shouldKeepSelectedModel &&
          shouldAvoidProvider(providerHealth)
        ) {
          let fallbackReplyModelId: string | undefined;

          if (
            preferredAgentModelId &&
            preferredAgentModelId !== finalModelId
          ) {
            const preferredDescriptor = await resolveAgentModelSlotDescriptor(
              preferredAgentModelId,
            ).catch(() => null);
            if (
              preferredDescriptor &&
              !shouldAvoidProvider(getProviderHealthSnapshot(preferredDescriptor.providerKey))
            ) {
              fallbackReplyModelId = preferredAgentModelId;
            }
          }

          if (!fallbackReplyModelId) {
            try {
              const { routeToModel } = await import("@/lib/ai/model-router");
              const replyFallbackRoute = await routeToModel({
                intent: "chat",
                subIntent: undefined,
                hasImage: false,
              });
              const fallbackDescriptor = await resolveAgentModelSlotDescriptor(
                replyFallbackRoute.id,
              ).catch(() => null);
              if (
                fallbackDescriptor &&
                !shouldAvoidProvider(getProviderHealthSnapshot(fallbackDescriptor.providerKey))
              ) {
                fallbackReplyModelId = replyFallbackRoute.id;
              }
            } catch (replyRouteError) {
              chatApiLogger.warn("[Smart Auto Mode] Failed to resolve reply fallback route after provider degradation:", replyRouteError);
            }
          }

          if (fallbackReplyModelId && fallbackReplyModelId !== finalModelId) {
            finalModelId = fallbackReplyModelId;
            const fallbackDescriptor = await resolveAgentModelSlotDescriptor(finalModelId).catch(
              () => null,
            );
            if (fallbackDescriptor) {
              agentModelSlots = upsertAgentModelSlot(agentModelSlots, "reply", {
                ...fallbackDescriptor,
                source: "provider_health_fallback",
                reason: providerHealth?.lastEventType || "degraded_provider",
                locked: false,
              });
            }
            chatApiLogger.warn(`[Smart Auto Mode] ♻️ Switched reply model due provider health: ${candidateReplyDescriptor.displayName || candidateReplyDescriptor.modelId} -> ${fallbackDescriptor?.displayName || fallbackReplyModelId}`);
          }
        }
      }
    }

    const session = await auth();

    if (!session?.user) {
      return new ChatSDKError("unauthorized:chat").toResponse();
    }

    const userType: UserType = session.user.type;

    const messageCount = await getMessageCountByUserId({
      id: session.user.id,
      differenceInHours: 24,
    });

    if (messageCount > entitlementsByUserType[userType].maxMessagesPerDay) {
      return new ChatSDKError("rate_limit:chat").toResponse();
    }

    // ========== 使用时间限制验证（后端安全检查） ==========
    try {
      // 从数据库获取网站设置
      const { siteSettings } = await import("@/lib/db/schema");
      const [settings] = await db.select().from(siteSettings).limit(1);
      
      if (settings?.usageTimeEnabled) {
        const now = new Date();
        const currentTime = `${String(now.getHours()).padStart(2, "0")}:${String(now.getMinutes()).padStart(2, "0")}`;
        const startTime = settings.usageTimeStart || "08:00";
        const endTime = settings.usageTimeEnd || "20:00";
        
        const isWithinUsageTime = currentTime >= startTime && currentTime <= endTime;
        
        if (!isWithinUsageTime) {
          chatApiLogger.info(`[Chat API] ⛔ 访问被拒绝：当前时间 ${currentTime} 不在允许范围 ${startTime}-${endTime}`);
          return NextResponse.json(
            { 
              error: "usage_time_restricted",
              message: settings.usageTimeMessage || "当前不在系统使用时间段内",
              currentTime,
              allowedTime: `${startTime} - ${endTime}`
            },
            { status: 403 }
          );
        }
        
        chatApiLogger.info(`[Chat API] ✅ 时间验证通过：${currentTime} 在允许范围 ${startTime}-${endTime}`);
      }
    } catch (timeCheckError) {
      chatApiLogger.error("[Chat API] ⚠️  时间验证失败（继续执行）:", timeCheckError);
      // 如果时间检查失败，继续执行（避免因检查逻辑错误导致系统不可用）
    }

    let chat = await getChatById({ id });
    let messagesFromDb: DBMessage[] = [];
    let messagesForMediaInput: DBMessage[] = [];

    if (chat) {
      if (chat.userId !== session.user.id) {
        return new ChatSDKError("forbidden:chat").toResponse();
      }
      // Only fetch messages if chat already exists
      messagesFromDb = await getMessagesByChatId({ id });
    } else {
      const title = await generateTitleFromUserMessage({
        message,
      });

      try {
        await saveChat({
          id,
          userId: session.user.id,
          title,
          visibility: selectedVisibilityType,
        });
      } catch (error) {
        const racedChat = await findChatWithRetry(id);
        if (!racedChat) {
          throw error;
        }

        if (racedChat.userId !== session.user.id) {
          return new ChatSDKError("forbidden:chat").toResponse();
        }

        chatApiLogger.warn("[Chat API] saveChat conflicted, reused existing chat:", {
          chatId: id,
          userId: session.user.id,
        });
      }

      chat = await findChatWithRetry(id);
      if (!chat) {
        throw new ChatSDKError("bad_request:database", "Failed to save chat");
      }

      if (chat.userId !== session.user.id) {
        return new ChatSDKError("forbidden:chat").toResponse();
      }

      // In a race scenario another request may have already written messages.
      messagesFromDb = await getMessagesByChatId({ id });
    }

    const loadedMessagesForBoundary = shouldIsolateDirectComposerContext ? [] : messagesFromDb;
    messagesFromDb = shouldIsolateDirectComposerContext
      ? []
      : pruneTaskBoundaryHistoryMessages({
          decision: taskBoundaryDecision,
          messages: loadedMessagesForBoundary,
          purpose: "model",
          hasCurrentImageInput: hasImageInputForConversationAction,
        });
    messagesForMediaInput = shouldIsolateDirectComposerContext
      ? []
      : pruneTaskBoundaryHistoryMessages({
          decision: taskBoundaryDecision,
          messages: loadedMessagesForBoundary,
          purpose: "media",
          hasCurrentImageInput: hasImageInputForConversationAction,
        });

    if (!requestWorkingState && !shouldIsolateDirectComposerContext) {
      requestWorkingState = await getConversationWorkingStateByChatId({
        chatId: id,
      });
    }
    if (!requestResolvedMediaInput) {
      requestResolvedMediaInput = resolveChatMediaInput({
        messageParts: message.parts as any[],
        historyMessages: messagesForMediaInput,
        contextPayload: effectiveContextPayload,
        requestOrigin,
        maxImages: 4,
      });
    }
    if (!requestTargetResolution) {
      requestTargetResolution = resolveTargetAssets({
        text: requestTextContent,
        mediaInput: requestResolvedMediaInput,
        contextPayload: effectiveContextPayload,
        workingState: effectiveWorkingState || undefined,
      });
    }
    if (
      requestResolvedMediaInput.currentMessageImageUrls.length === 0 &&
      smartAutoHistoryImages.length === 0 &&
      requestTargetResolution.targetImageUrls.length > 0
    ) {
      smartAutoHistoryImages = requestTargetResolution.targetImageUrls.slice(0, 4);
    }

    const uiMessages = [...convertToUIMessages(messagesFromDb), message];
    const hiddenPromptText = typeof hiddenPrompt === "string" ? hiddenPrompt.trim() : "";
    const hiddenPromptPrefix = hiddenPromptText ? `${hiddenPromptText}\n\n` : "";
    const uiMessagesForModel = hiddenPromptText
      ? applyHiddenPromptToMessages(uiMessages, hiddenPromptText)
      : uiMessages;

    if (hiddenPromptText) {
      const hiddenPromptLines = hiddenPromptText
        .split("\n")
        .map((line) => line.trim())
        .filter(Boolean);
      chatApiLogger.info("[Chat API] Hidden workflow prompt summary:", {
        lineCount: hiddenPromptLines.length,
        preview: hiddenPromptLines.slice(0, 12),
      });
    }

    const { longitude, latitude, city, country } = geolocation(request);

    const requestHints: RequestHints = {
      longitude,
      latitude,
      city,
      country,
    };

    const insertedUserMessage = await db
      .insert(messageTable)
      .values({
        chatId: id,
        id: message.id,
        role: "user",
        parts: message.parts as any,
        attachments: [],
        createdAt: new Date(),
        videoStorageStatus: null,
        temporaryVideoUrl: null,
        permanentVideoUrl: null,
        archivedAt: null,
        videoMetadata: null,
      })
      .onConflictDoNothing({
        target: [messageTable.id],
      })
      .returning({ id: messageTable.id });

    if (insertedUserMessage.length === 0) {
      chatApiLogger.warn(`[Chat API] Duplicate user message ignored (chatId=${id}, messageId=${message.id})`);
      const duplicateStream = createUIMessageStream({
        execute: async ({ writer }) => {
          await replayAssistantMessagesForDuplicateRequest({
            chatId: id,
            userMessageId: message.id,
            writer,
            source: "duplicate-user-message",
          });
        },
      });
      return createSseResponse(duplicateStream);
    }

    if (requestResolvedMediaInput && requestTargetResolution) {
      try {
        await createMessageTargetResolution({
          userId: session.user.id,
          chatId: id,
          messageId: message.id,
          projectId: contextPayload?.projectId || null,
          rawText: requestTextContent,
          uploadedAssetIds: requestResolvedMediaInput.uploadedAssetIds,
          uploadedImageUrls: requestResolvedMediaInput.currentMessageImageUrls,
          selectedAssetIds: requestResolvedMediaInput.selectedAssetIds,
          selectedImageUrls: requestResolvedMediaInput.selectedImageUrls,
          candidateAssetIds: requestResolvedMediaInput.candidateAssetIds,
          candidateImageUrls: requestResolvedMediaInput.imageRefs.map((ref) => ref.url),
          resolvedAssetIds: requestTargetResolution.targetAssetIds,
          resolvedImageUrls: requestTargetResolution.targetImageUrls,
          resolutionMode: requestTargetResolution.resolutionMode,
          confidence: requestTargetResolution.confidence,
          needsClarification: requestTargetResolution.needsClarification,
          reasoning: {
            reason: requestTargetResolution.reason,
            fromHistory: requestTargetResolution.fromHistory,
            focusPolicy: contextPayload?.focusPolicy || null,
            contextSource: contextPayload?.source || null,
          },
        });

        await persistResolvedTargetTurn({
          userId: session.user.id,
          chatId: id,
          projectId: contextPayload?.projectId || null,
          currentIntent:
            smartAutoExecution?.routeIntent ||
            smartAutoDetectedIntent ||
            (requestResolvedMediaInput.hasImage
              ? "vision"
              : requestBody.videoParams
                ? "video_gen"
                : null),
          currentFocusAssetIds: requestTargetResolution.targetAssetIds,
          currentFocusImageUrls: requestTargetResolution.targetImageUrls,
          selectedAssetIds: requestResolvedMediaInput.selectedAssetIds,
          selectedImageUrls: requestResolvedMediaInput.selectedImageUrls,
          lastUploadedAssetIds: requestResolvedMediaInput.uploadedAssetIds,
          lastUploadedImageUrls: requestResolvedMediaInput.currentMessageImageUrls,
          lastReferencedAssetIds: requestTargetResolution.candidateAssetIds,
          lastReferencedImageUrls: requestTargetResolution.candidateImageUrls,
          lastResolvedTargetAssetIds: requestTargetResolution.targetAssetIds,
          lastResolvedTargetImageUrls: requestTargetResolution.targetImageUrls,
          activeCanvasNodeIds: contextPayload?.selectedNodeIds || [],
          lastCanvasSnapshot:
            Array.isArray(contextPayload?.canvasImageNodes) && contextPayload?.canvasImageNodes.length > 0
              ? {
                  source: contextPayload?.source || "canvas",
                  selectedNodeIds: contextPayload?.selectedNodeIds || [],
                  canvasImageNodes: contextPayload?.canvasImageNodes,
                }
              : null,
          lastMessageId: message.id,
          text: requestTextContent,
          resolutionMode: requestTargetResolution.resolutionMode,
          confidence: requestTargetResolution.confidence,
        });
      } catch (memoryError) {
        chatApiLogger.warn("[Chat API] Failed to persist context-memory state:", memoryError);
      }
    }

    const buildCurrentAgentTargetLockPayload = () => {
      if (!shouldRunAgentConversation) return null;
      if (composerMode !== "agent") return null;
      if (effectiveContextPayload?.source !== "canvas") return null;
      if (!requestResolvedMediaInput || !requestTargetResolution) return null;

      return buildAgentTargetLockPayload({
        requestTargetResolution,
        requestResolvedMediaInput,
        needsClarification: smartAutoNeedsClarification,
        clarificationMessage:
          smartAutoClarificationQuestion || smartAutoFriendlyMessage || undefined,
      });
    };

    const writeCurrentAgentTargetLockChunk = (
      writer: StreamWriter,
      label: string,
    ) => {
      const payload = buildCurrentAgentTargetLockPayload();
      if (!payload) return;
      writeAgentTargetLockChunk(writer, payload, label);
    };

    const streamId = generateUUID();
    await createStreamId({ streamId, chatId: id });

    const promptOnlySourceImageUrls =
      requestResolvedMediaInput.currentMessageImageUrls.length > 0
        ? requestResolvedMediaInput.currentMessageImageUrls.slice(0, 4)
        : requestTargetResolution?.targetImageUrls.slice(0, 4) || smartAutoHistoryImages.slice(0, 4);
    const promptOnlySourceAssetIds =
      requestTargetResolution?.targetAssetIds?.length
        ? requestTargetResolution.targetAssetIds
        : requestResolvedMediaInput.uploadedAssetIds;
    const wantsPromptOnlyFromImageContext =
      shouldRunAgentConversation &&
      !smartAutoNeedsClarification &&
      promptOnlySourceImageUrls.length > 0 &&
      taskBoundaryDecision.taskType === "prompt_only";

    if (wantsPromptOnlyFromImageContext) {
      let promptOnlyImageSummary = "";
      try {
        const { summarizeImageForExecutionReport } = await import("@/lib/ai/smart-analyzer");
        const summaryTimeoutMs = getBudgetedTimeout({
          startedAt: requestStartedAt,
          preferredMs: SMART_AUTO_IMAGE_SUMMARY_TIMEOUT_MS,
          minimumMs: 6_000,
        });
        if (summaryTimeoutMs) {
          const summaryAssetIds = Array.from(
              new Set([
                ...extractMessageImageAssetIds(message.parts as any[]),
                ...((effectiveContextPayload?.selectedAssetIds || []).filter(Boolean) as string[]),
              ]),
            );
          const summary = await withOperationTimeout(
            summarizeImageForExecutionReport({
              text: requestTextContent,
              imageUrls: promptOnlySourceImageUrls,
              context: effectiveAutoContextText || undefined,
              preferredModelId: preferredAgentModelId,
              assetIds:
                promptOnlySourceAssetIds.length > 0 ? promptOnlySourceAssetIds : summaryAssetIds,
              timeoutMs: summaryTimeoutMs,
            }),
            "promptOnlyImageSummary",
            summaryTimeoutMs,
          );
          if (summary?.trim()) {
            promptOnlyImageSummary = summary.trim();
          }
        }
      } catch (promptOnlySummaryError) {
        chatApiLogger.warn("[Chat API] Prompt-only image summary failed:", promptOnlySummaryError);
      }

      let promptOnlyOptimizedPrompt = smartAutoOptimizedPrompt?.trim() || "";
      if (!promptOnlyOptimizedPrompt) {
        try {
          const { optimizePromptWithLLM, optimizePrompt } = await import("@/lib/ai/prompt-optimizer");
          const promptSeed = buildPromptOnlyOptimizationSeed({
            text: requestTextContent,
            imageSummary: promptOnlyImageSummary,
          });
          const optimizedResult = await optimizePromptWithLLM({
            originalPrompt: promptSeed,
            intent: "image_gen",
            historyMessages: smartAutoHistoryMessagesFromDb
              .map((msg) => {
                const parts = Array.isArray(msg.parts) ? (msg.parts as any[]) : [];
                const content = parts
                  .filter((part: any) => part?.type === "text")
                  .map((part: any) => String(part?.text || ""))
                  .join(" ")
                  .trim();
                if (!content) return null;
                return {
                  role: msg.role as "user" | "assistant",
                  content: content.slice(0, 300),
                };
              })
              .filter(Boolean) as Array<{ role: "user" | "assistant"; content: string }>,
            context: effectiveAutoContextText || undefined,
            preferredModelId: preferredAgentModelId,
          }).catch(() =>
            optimizePrompt({
              originalPrompt: promptSeed,
              intent: "image_gen",
            }),
          );
          promptOnlyOptimizedPrompt = String(optimizedResult?.optimizedPrompt || "").trim();
        } catch (promptOnlyOptimizeError) {
          chatApiLogger.warn("[Chat API] Prompt-only optimization failed:", promptOnlyOptimizeError);
        }
      }

      if (!promptOnlyOptimizedPrompt) {
        promptOnlyOptimizedPrompt = buildPromptOnlyOptimizationSeed({
          text: requestTextContent,
          imageSummary: promptOnlyImageSummary,
        });
      }

      const promptOnlyMessage = buildPromptOnlyReply({
        userText: requestTextContent,
        imageSummary: promptOnlyImageSummary,
        optimizedPrompt: promptOnlyOptimizedPrompt,
      });

      const promptOnlyStream = createUIMessageStream({
        execute: async ({ writer }) => {
          const messageId = generateUUID();
          writeAgentProgressChunk(
            writer,
            {
              stage: "planning",
              currentStep: "analyze",
              title: "正在提炼可执行提示词",
              message: "我在结合当前目标图和上下文整理更稳定的提示词。",
              toolName: "promptOnly",
              capability: "prompt_only",
            },
            "prompt-only:progress-planning",
          );
          writeCurrentAgentTargetLockChunk(writer, "prompt-only:target-lock");
          writeAssistantTextChunk(writer, promptOnlyMessage, "prompt-only:reply", messageId);

          await saveMessages({
            messages: [
              {
                id: messageId,
                chatId: id,
                role: "assistant",
                parts: [{ type: "text", text: promptOnlyMessage }],
                attachments: [],
                createdAt: new Date(),
                videoStorageStatus: null,
                temporaryVideoUrl: null,
                permanentVideoUrl: null,
                archivedAt: null,
                videoMetadata: null,
              },
            ],
          });

          try {
            await persistPromptOnlyTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              messageId,
              text: requestTextContent,
              optimizedPrompt: promptOnlyOptimizedPrompt,
              imageSummary: promptOnlyImageSummary,
              sourceImageUrls: promptOnlySourceImageUrls,
            });
          } catch (promptOnlyMemoryError) {
            chatApiLogger.warn("[Chat API] Failed to persist prompt-only response state:", promptOnlyMemoryError);
          }

          writeAgentProgressChunk(
            writer,
            {
              stage: "completed",
              currentStep: "finalize",
              title: "提示词整理完成",
              message: "已经给出可直接复用的优化提示词。",
              toolName: "promptOnly",
              capability: "prompt_only",
            },
            "prompt-only:progress-completed",
          );
        },
      });

      return createSseResponse(promptOnlyStream);
    }

    if (shouldRunAgentConversation && smartAutoNeedsClarification) {
      const clarificationBypass = resolveClarificationBypass({
        text: message.parts
          .filter((part): part is { type: "text"; text: string } => part.type === "text")
          .map((part) => part.text)
          .join(" ")
          .trim(),
        hasCurrentImageInput: message.parts.some((part: any) =>
          part?.type === "file" || part?.type === "image" || part?.type === "image_url"
        ),
        hasHistoryImageInput: smartAutoHistoryImages.length > 0,
        hasCanvasSelection: Boolean(effectiveContextPayload?.selectedNodeIds?.length),
        targetResolutionMode: requestTargetResolution?.resolutionMode,
        executionMode: smartAutoExecution?.mode,
        friendlyMessage: smartAutoFriendlyMessage,
      });

      if (clarificationBypass.shouldBypass) {
        smartAutoNeedsClarification = false;
        smartAutoClarificationQuestion = undefined;
        smartAutoFriendlyMessage = clarificationBypass.nextFriendlyMessage;
        chatApiLogger.info("[Smart Auto Mode] ✅ Force direct execution (skip clarification)");
      }
    }

    if (shouldRunAgentConversation) {
      const canvasClarificationGate = resolveCanvasAgentClarificationGate({
        text: requestTextContent,
        composerMode,
        contextPayload: effectiveContextPayload,
        mediaInput: requestResolvedMediaInput,
        targetResolution: requestTargetResolution,
        taskBoundaryDecision,
        executionMode: smartAutoExecution?.mode,
        actionKind: resolvedConversationAction.kind,
      });

      if (canvasClarificationGate.shouldClarify) {
        smartAutoNeedsClarification = true;
        smartAutoClarificationQuestion =
          canvasClarificationGate.clarificationMessage || smartAutoClarificationQuestion;
        smartAutoFriendlyMessage =
          canvasClarificationGate.clarificationMessage || smartAutoFriendlyMessage;
        chatApiLogger.info("[Smart Auto Mode] 🧭 Canvas clarification gate triggered:", {
          reason: canvasClarificationGate.reason,
          executionMode: smartAutoExecution?.mode,
          resolutionMode: requestTargetResolution?.resolutionMode,
          selectedCount: requestResolvedMediaInput?.selectedImageRefs.length || 0,
          candidateCount: requestTargetResolution?.candidateRefs.length || 0,
        });
      }
    }

    if (shouldRunAgentConversation && smartAutoNeedsClarification) {
      const clarificationMessage = resolveClarificationMessage({
        clarificationQuestion: smartAutoClarificationQuestion,
        friendlyMessage: smartAutoFriendlyMessage,
      });

      const clarificationStream = createUIMessageStream({
        execute: async ({ writer }) => {
          const messageId = generateUUID();
          writeAgentProgressChunk(
            writer,
            {
              stage: "clarify",
              currentStep: "lock_target",
              title: "等待你确认关键信息",
              message:
                smartAutoClarificationQuestion ||
                smartAutoFriendlyMessage ||
                "我需要先确认目标图或执行范围，避免误处理。",
              toolName: "clarification",
              capability: smartAutoExecution?.preferredCapability || undefined,
            },
            "clarification:progress",
          );
          writeCurrentAgentTargetLockChunk(writer, "clarification:target-lock");
          writer.write({
            type: "data-appendMessage",
            data: JSON.stringify({
              id: messageId,
              role: "assistant",
              parts: [{ type: "text", text: clarificationMessage }],
            }),
          });

          await saveMessages({
            messages: [
              {
                id: messageId,
                chatId: id,
                role: "assistant",
                parts: [{ type: "text", text: clarificationMessage }],
                attachments: [],
                createdAt: new Date(),
                videoStorageStatus: null,
                temporaryVideoUrl: null,
                permanentVideoUrl: null,
                archivedAt: null,
                videoMetadata: null,
              },
            ],
          });

          try {
            await persistClarificationTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              messageId,
              text: requestTextContent,
              clarificationMessage,
              currentIntent: smartAutoDetectedIntent || null,
              pendingGridConfirmation:
                shouldAskGridConfirmation && pendingGridConfirmation
                  ? pendingGridConfirmation
                  : null,
            });
          } catch (clarificationPersistError) {
            chatApiLogger.warn("[Chat API] Failed to persist clarification state:", clarificationPersistError);
          }
        },
      });

      return createSseResponse(clarificationStream);
    }

    if (
      shouldRunAgentConversation &&
      smartAutoWorkflowDecision?.workflowType === "storyboard_video" &&
      (smartAutoWorkflowDecision?.action === "revision_requested" ||
        smartAutoWorkflowDecision?.action === "cancel_requested")
    ) {
      const workflowReplyStream = createUIMessageStream({
        execute: async ({ writer }) => {
          const messageId = generateUUID();
          const workflowFollowupResult = await handleStoryboardWorkflowFollowup({
            action: smartAutoWorkflowDecision.action as "revision_requested" | "cancel_requested",
            workflowId: smartAutoWorkflowDecision.workflowId,
            text: requestTextContent,
            friendlyMessage: smartAutoFriendlyMessage,
            onProgress: (event) => {
              safeWriteStreamChunk(
                writer,
                {
                  type: "data-videoStoryboard",
                  data: JSON.stringify(event),
                },
                `storyboard-revision:${event.stage}`,
              );
            },
          });
          const replyText = workflowFollowupResult.replyText;

          writer.write({
            type: "data-appendMessage",
            data: JSON.stringify({
              id: messageId,
              role: "assistant",
              parts: [{ type: "text", text: replyText }],
              attachments: [],
            }),
          });

          await saveMessages({
            messages: [
              {
                id: messageId,
                chatId: id,
                role: "assistant",
                parts: [{ type: "text", text: replyText }],
                attachments: [],
                createdAt: new Date(),
                videoStorageStatus: null,
                temporaryVideoUrl: null,
                permanentVideoUrl: null,
                archivedAt: null,
                videoMetadata: workflowFollowupResult.videoMetadata,
              },
            ],
          });

          try {
            if (
              smartAutoWorkflowDecision?.action === "revision_requested" &&
              smartAutoWorkflowDecision.workflowId
            ) {
              await persistStoryboardRevisionTurn({
                userId: session.user.id,
                chatId: id,
                projectId: contextPayload?.projectId || null,
                messageId,
                text: requestTextContent,
                taskId: smartAutoWorkflowDecision.workflowId,
                status: workflowFollowupResult.nextWorkflowStatus,
              });
            } else if (smartAutoWorkflowDecision?.action === "cancel_requested") {
              await persistWorkflowCancelledTurn({
                userId: session.user.id,
                chatId: id,
                projectId: contextPayload?.projectId || null,
                messageId,
                text: requestTextContent,
                workflowType: "storyboard_video",
                workflowId: smartAutoWorkflowDecision?.workflowId,
                status: workflowFollowupResult.nextWorkflowStatus,
              });
            }
          } catch (workflowPersistError) {
            chatApiLogger.warn("[Chat API] Failed to persist storyboard workflow interruption state:", workflowPersistError);
          }
        },
      });

      return createSseResponse(workflowReplyStream);
    }

    if (
      shouldRunAgentConversation &&
      smartAutoWorkflowDecision?.workflowType === "storyboard_video" &&
      smartAutoWorkflowDecision?.action === "confirmed" &&
      smartAutoWorkflowDecision.workflowId
    ) {
      const confirmedTaskId = smartAutoWorkflowDecision.workflowId;
      const confirmedStoryboardStream = createUIMessageStream({
        execute: async ({ writer }) => {
          const acknowledgeMessageId = generateUUID();
          const { acknowledgeMessage, acknowledgeMetadata } =
            buildStoryboardConfirmedAck(confirmedTaskId);

          writer.write({
            type: "data-appendMessage",
            data: JSON.stringify({
              id: acknowledgeMessageId,
              role: "assistant",
              parts: [{ type: "text", text: acknowledgeMessage }],
              attachments: [],
            }),
          });

          await saveMessages({
            messages: [
              {
                id: acknowledgeMessageId,
                chatId: id,
                role: "assistant",
                parts: [{ type: "text", text: acknowledgeMessage }],
                attachments: [],
                createdAt: new Date(),
                videoStorageStatus: null,
                temporaryVideoUrl: null,
                permanentVideoUrl: null,
                archivedAt: null,
                videoMetadata: acknowledgeMetadata,
              },
            ],
          });

          try {
            await persistStoryboardConfirmedTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              messageId: acknowledgeMessageId,
              text: requestTextContent,
              taskId: confirmedTaskId,
              status: "confirmed",
            });
          } catch (storyboardConfirmMemoryError) {
            chatApiLogger.warn("[Chat API] Failed to persist storyboard confirmation memory:", storyboardConfirmMemoryError);
          }

          try {
            await persistStoryboardExecutionStartedTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              messageId: acknowledgeMessageId,
              text: requestTextContent,
              taskId: confirmedTaskId,
              status: "running",
            });
          } catch (storyboardExecutionStartError) {
            chatApiLogger.warn("[Chat API] Failed to persist storyboard execution start state:", storyboardExecutionStartError);
          }

          const { executionResult, firstVideoUrl, finalVideoMetadata } =
            await executeStoryboardConfirmedWorkflow({
              taskId: confirmedTaskId,
              onProgress: (event) => {
                safeWriteStreamChunk(
                  writer,
                  {
                    type: "data-videoStoryboard",
                    data: JSON.stringify(event),
                  },
                  `storyboard-confirmed:${event.stage}`,
                );
              },
            });

          const finalMessageId = generateUUID();
          writer.write({
            type: "data-appendMessage",
            data: JSON.stringify({
              id: finalMessageId,
              role: "assistant",
              parts: [{ type: "text", text: executionResult.markdown }],
              attachments: [],
            }),
          });

          await saveMessages({
            messages: [
              {
                id: finalMessageId,
                chatId: id,
                role: "assistant",
                parts: [{ type: "text", text: executionResult.markdown }],
                attachments: [],
                createdAt: new Date(),
                videoStorageStatus: firstVideoUrl ? "temporary" : null,
                temporaryVideoUrl: firstVideoUrl || null,
                permanentVideoUrl: null,
                archivedAt: null,
                videoMetadata: finalVideoMetadata,
              },
            ],
          });

          await attachVideoStoryboardTaskMessage({
            taskId: executionResult.taskId,
            messageId: finalMessageId,
          }).catch((taskAttachError) => {
            chatApiLogger.warn("[Chat API] Failed to attach confirmed storyboard task with message:", taskAttachError);
          });

          try {
            await persistStoryboardExecutionCompletedTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              messageId: finalMessageId,
              text: requestTextContent,
              taskId: executionResult.taskId,
              status: executionResult.status,
              successCount: executionResult.successCount,
              failedCount: executionResult.failedCount,
              firstVideoUrl: firstVideoUrl || undefined,
            });
          } catch (storyboardExecutionCompletedError) {
            chatApiLogger.warn("[Chat API] Failed to persist storyboard execution completion state:", storyboardExecutionCompletedError);
          }

          if (firstVideoUrl) {
            await consumeGeneratedVideoPoints({
              userId: session.user.id,
              chatId: id,
              messageId: finalMessageId,
              modelRefs: executionResult.modelRefs,
              duration: Number((finalVideoMetadata as any)?.duration) || undefined,
              resolution:
                String((finalVideoMetadata as any)?.resolution || "").trim() ||
                undefined,
            });

            scheduleVideoArchive({
              chatId: id,
              messageId: finalMessageId,
              text: executionResult.markdown,
              temporaryVideoUrl: firstVideoUrl,
              taskId: finalMessageId,
              metadata: {
                storyboard: {
                  enabled: true,
                  taskId: executionResult.taskId,
                  successCount: executionResult.successCount,
                  failedCount: executionResult.failedCount,
                },
                status: executionResult.status,
                updatedAt: Date.now(),
              },
            });
          }
        },
      });

      return createSseResponse(confirmedStoryboardStream);
    }

    if (!agentPresetId && agentModePayload?.modeType === "detail_replacement") {
      const replacementReferences = normalizeAgentModeReferences(agentModePayload);
      const detailReplacementStrategy =
        normalizeAgentModeDetailReplacementStrategy(agentModePayload);
      if (replacementReferences.length === 0) {
        return NextResponse.json(
          {
            code: "bad_request:api",
            message: "详情参考图替换至少需要 1 张详情参考图",
          },
          { status: 400 },
        );
      }

      const uploadedImageParts = extractCurrentMessageImageParts(message.parts as any[]);
      const sourceImages = normalizeAgentModeSourceImages(agentModePayload);
      const inferredImageParts = resolveImagePartsByReferenceExclusion({
        uploadedImageParts,
        referenceImageUrls: replacementReferences.map((item) => item.imageUrl),
      });
      const productSourceImages =
        sourceImages.productImages.length > 0
          ? sourceImages.productImages
          : inferredImageParts.productParts.map((part) => ({
              url: part.url,
              label: part.name || "产品图",
              name: part.name || "产品图",
              assetId: part.assetId || null,
            }));
      const modelSourceImage =
        sourceImages.modelImage ||
        (inferredImageParts.modelPart
          ? {
              url: inferredImageParts.modelPart.url,
              label: inferredImageParts.modelPart.name || "模特图",
              name: inferredImageParts.modelPart.name || "模特图",
              assetId: inferredImageParts.modelPart.assetId || null,
            }
          : null);
      const replacementReferenceUrlSet = new Set(
        replacementReferences.map((item) => item.imageUrl),
      );
      const productInputImageUrls = Array.from(
        new Set(
          productSourceImages
            .map((item) => item.url)
            .filter((url) => /^https?:\/\//i.test(url) && !replacementReferenceUrlSet.has(url)),
        ),
      ).slice(0, 16);
      const modelInputImageUrl =
        modelSourceImage?.url && !replacementReferenceUrlSet.has(modelSourceImage.url)
          ? modelSourceImage.url
          : null;

      if (productInputImageUrls.length === 0) {
        return NextResponse.json(
          {
            code: "bad_request:api",
            message: "详情参考图替换至少需要 1 张产品图",
          },
          { status: 400 },
        );
      }

      const directReplacementModels = await getEnabledAiModelsWithProvider().catch((error) => {
        chatApiLogger.warn("[Chat API] Failed to load models for direct detail replacement:", error);
        return undefined;
      });
      const resolvedModelRef = await resolveDirectReplacementModelRef({
        selectedChatModel,
        finalModelId,
        models: directReplacementModels,
      });
      if (!resolvedModelRef || resolvedModelRef === "auto") {
        return NextResponse.json(
          {
            code: "bad_request:api",
            message: "当前风格化未配置可用的生图模型",
          },
          { status: 400 },
        );
      }

      const sanitizedUserSupplementPrompt = normalizeAgentSupplementPrompt(
        requestTextContent,
        "详情参考图替换",
      );
      const baseReplacementPrompt =
        detailReplacementStrategy === "product_only"
          ? "仅替换参考详情图中的产品主体"
          : buildAgentSlotPrompt({
              workflowPrompt: hiddenPromptText || null,
              slotPrompt: "",
              userSupplementPrompt: sanitizedUserSupplementPrompt || null,
              includeSlotTitle: false,
              modeType: "detail_replacement",
            }) ||
            hiddenPromptText ||
            sanitizedUserSupplementPrompt ||
            "执行详情参考图背景替换";
      const resolvedAspectRatio = "auto";
      const resolvedImageSize =
        effectiveImageParams?.imageSize || defaultImageQualityParams.imageSize;
      const sourceAssetIds = Array.from(
        new Set(
          [
            ...productSourceImages.map((item) => item.assetId),
            modelSourceImage?.assetId,
            ...uploadedImageParts.map((part) => part.assetId),
          ].filter((assetId): assetId is string => Boolean(assetId)),
        ),
      );

      const directDetailReplacementStream = createUIMessageStream({
        execute: async ({ writer }) => {
          writeAssistantTextChunk(
            writer,
            "<!-- IMAGE_GENERATION_START -->",
            "agent-mode:detail-replacement:start",
          );
          if (contextPayload?.source === "canvas") {
            writeImageGenerationStatusChunk(
              writer,
              {
                phase: "processing",
                modelName: resolvedModelRef,
                imageCount: replacementReferences.length,
              },
              "agent-mode:detail-replacement:status-processing",
            );
          }

          let successCount = 0;
          let resolvedModelDisplayName = resolvedModelRef;
          const replacementVisionModels =
            directReplacementModels ||
            (await getEnabledAiModelsWithProvider().catch((error) => {
              chatApiLogger.warn("[Chat API] Failed to load configured vision models for direct detail replacement:", error);
              return undefined;
            }));
          const replacementScenePlanningRuntime =
            await resolveReplacementScenePlanningRuntime({
              models: replacementVisionModels,
            });
          const stopKeepalive = startStreamKeepalive(
            writer,
            "agent-mode:detail-replacement",
            12_000,
          );

          const emitReplacementResultMessage = async (params: {
            reference: (typeof replacementReferences)[number];
            bodyText?: string | null;
            image: {
              originalUrl: string;
              thumbnailUrl: string;
            };
            imageSizeLabel?: string | null;
            modelDisplayName?: string | null;
            sourceImageUrls: string[];
            streamLabel: string;
            promptForPersistence?: string | null;
          }) => {
            const persistedImageSize =
              String(params.imageSizeLabel || "").trim() || resolvedImageSize;
            const assistantText = prependImageModelBadge(
              [
                `<!-- AGENT_REPLACEMENT_CARD_ID:${String(params.reference.id || "").trim()} -->`,
                `### ${params.reference.label}`,
                String(params.bodyText || "").trim(),
                buildAgentToolImagesMarkdown([
                  {
                    originalUrl: params.image.originalUrl,
                    thumbnailUrl: params.image.thumbnailUrl,
                    imageSize: persistedImageSize,
                  },
                ]),
              ]
                .filter(Boolean)
                .join("\n\n"),
              params.modelDisplayName || null,
            );
            const assistantMessageId = generateUUID();

            await saveMessages({
              messages: [
                {
                  id: assistantMessageId,
                  chatId: id,
                  role: "assistant",
                  parts: [{ type: "text", text: assistantText }],
                  attachments: [],
                  createdAt: new Date(),
                  videoStorageStatus: null,
                  temporaryVideoUrl: null,
                  permanentVideoUrl: null,
                  archivedAt: null,
                  videoMetadata: null,
                },
              ],
            });

            await saveGeneratedImages(
              assistantText,
              session.user.id,
              id,
              assistantMessageId,
              params.promptForPersistence || baseReplacementPrompt,
              resolvedModelRef,
              {
                sourceAssetIds,
                sourceImageUrls: params.sourceImageUrls,
                relationType: "edited_from",
                sourceType: "detail_replacement",
                projectId: contextPayload?.projectId || null,
                userPrompt: requestTextContent,
                optimizedPrompt: params.promptForPersistence || baseReplacementPrompt,
                requestedImageCount: 1,
                aspectRatio: resolvedAspectRatio,
                imageSize: persistedImageSize,
              },
            );

            writeAssistantTextChunk(
              writer,
              assistantText,
              params.streamLabel,
              assistantMessageId,
            );

            if (contextPayload?.source === "canvas") {
              writeCanvasMediaChunk(
                writer,
                {
                  messageId: assistantMessageId,
                  imageUrls: [params.image.originalUrl],
                  prompt: params.promptForPersistence || baseReplacementPrompt,
                  sourceImageUrls: params.sourceImageUrls,
                },
                `${params.streamLabel}:canvas-media`,
              );
            }
          };

          try {
            await runBoundedParallel(
              Array.from(replacementReferences.entries()),
              AGENT_REPLACEMENT_PARALLEL_WORKER_COUNT,
              async ([referenceIndex, reference]) => {
              if (reference.passthrough === true) {
                const referenceSourceImageUrls = Array.from(
                  new Set([
                    ...productInputImageUrls,
                    ...(modelInputImageUrl ? [modelInputImageUrl] : []),
                    reference.imageUrl,
                  ]),
                );
                await emitReplacementResultMessage({
                  reference,
                  bodyText: "已按人工标记沿用参考图，直接应用当前切片，不参与继续生成。",
                  image: {
                    originalUrl: reference.imageUrl,
                    thumbnailUrl: reference.imageUrl,
                  },
                  modelDisplayName: null,
                  sourceImageUrls: referenceSourceImageUrls,
                  streamLabel: "agent-mode:image:detail-replacement:item-passthrough",
                });
                successCount += 1;
                return;
              }

              const replacementExecutionPlan = await analyzeReplacementExecutionPlan({
                modeType: "detail_replacement",
                replacementStrategy: detailReplacementStrategy,
                referenceImageUrl: reference.imageUrl,
                referenceLabel: reference.label,
                productImageUrls: productInputImageUrls,
                modelImageUrl: modelInputImageUrl,
                workflowPrompt:
                  detailReplacementStrategy === "product_only"
                    ? null
                    : baseReplacementPrompt || hiddenPromptText || null,
                planningRuntime: replacementScenePlanningRuntime,
                models: replacementVisionModels,
              });
              const referenceSourceImageUrls = Array.from(
                new Set([
                  ...productInputImageUrls,
                  ...(modelInputImageUrl ? [modelInputImageUrl] : []),
                  reference.imageUrl,
                ]),
              );

              if (!replacementExecutionPlan.shouldReplace) {
                await emitReplacementResultMessage({
                  reference,
                  bodyText: replacementExecutionPlan.reason,
                  image: {
                    originalUrl: reference.imageUrl,
                    thumbnailUrl: reference.imageUrl,
                  },
                  modelDisplayName: null,
                  sourceImageUrls: referenceSourceImageUrls,
                  streamLabel: "agent-mode:image:detail-replacement:item",
                });
                successCount += 1;
                return;
              }

              const referenceGeometry = await resolveReplacementReferenceGeometry(reference.imageUrl);
              const generationAspectRatio = referenceGeometry?.aspectRatio || resolvedAspectRatio;
              const selectedProductIndexes = replacementExecutionPlan.scenePlan
                .selectedProductImageIndexes.map((index) => index - 1)
                .filter((index) => index >= 0 && index < productInputImageUrls.length);
              const selectedProductContextImageUrls =
                selectedProductIndexes.length > 0
                  ? selectedProductIndexes.map((index) => productInputImageUrls[index]!)
                  : productInputImageUrls.slice(0, Math.min(productInputImageUrls.length, 2));
              const sourceImageUrls = Array.from(
                new Set([
                      ...selectedProductContextImageUrls,
                      ...(replacementExecutionPlan.scenePlan.useModelImage &&
                      detailReplacementStrategy !== "product_only" &&
                      modelInputImageUrl
                        ? [modelInputImageUrl]
                        : []),
                      reference.imageUrl,
                ]),
              );
                const replacementPrompt = buildAgentReplacementPrompt({
                  basePrompt: baseReplacementPrompt,
                  modeType: "detail_replacement",
                  replacementStrategy: detailReplacementStrategy,
                  referenceLabel: reference.label,
                  referenceIndex,
                  totalReferences: replacementReferences.length,
                  hasModelImage:
                    replacementExecutionPlan.scenePlan.useModelImage &&
                    detailReplacementStrategy !== "product_only" &&
                    Boolean(modelInputImageUrl),
                productImageCount: selectedProductContextImageUrls.length,
                originalProductImageCount: productInputImageUrls.length,
                templateReferenceCount: 0,
                scenePlan: replacementExecutionPlan.scenePlan,
                referenceGeometry,
              });

              try {
                const result = await generateCanvasImage({
                  prompt: replacementPrompt,
                  negativePrompt: effectiveImageParams?.negativePrompt,
                  model: resolvedModelRef,
                  ownerKey: session.user.id,
                  aspectRatio: generationAspectRatio,
                  imageSize: resolvedImageSize,
                  imageCount: 1,
                  referenceImages: sourceImageUrls,
                  debugLabel: "agent-detail-replacement",
                  debugMeta: {
                    referenceLabel: reference.label,
                    referenceWidth: referenceGeometry?.width,
                    referenceHeight: referenceGeometry?.height,
                    referenceAspectRatio: referenceGeometry?.aspectRatio,
                  },
                  onQueueStatusChange:
                    contextPayload?.source === "canvas"
                      ? async (queueStatus) => {
                          writeImageGenerationStatusChunk(
                            writer,
                            {
                              phase:
                                queueStatus.status === "running"
                                  ? "processing"
                                  : "queued",
                              modelName:
                                queueStatus.modelName || resolvedModelDisplayName || resolvedModelRef,
                              imageCount: 1,
                              queuePosition: queueStatus.queuePosition,
                              sameModelRunningCount: queueStatus.sameModelRunningCount,
                              concurrencyLimit: queueStatus.concurrencyLimit,
                              estimatedWaitMs: queueStatus.estimatedWaitMs,
                            },
                            `agent-mode:detail-replacement:queue:${reference.id}`,
                          );
                        }
                      : undefined,
                });
                resolvedModelDisplayName = result.model || resolvedModelDisplayName;
                const firstImage = result.images[0];
                if (!firstImage) {
                  throw new Error("未返回结果图片");
                }

                let finalImage = firstImage;
                let finalImageSizeLabel = resolvedImageSize;
                try {
                  const normalizedImage = await normalizeReplacementResultImage({
                    generatedImageUrl: firstImage.originalUrl,
                    generatedThumbnailUrl: firstImage.thumbnailUrl,
                    referenceImageUrl: reference.imageUrl,
                    referenceGeometry,
                    uploadPrefix: "agent-detail-replacement",
                  });
                  finalImage = {
                    originalUrl: normalizedImage.originalUrl,
                    thumbnailUrl: normalizedImage.thumbnailUrl || normalizedImage.originalUrl,
                  };
                  finalImageSizeLabel = normalizedImage.imageSize;
                } catch (normalizeError) {
                  chatApiLogger.warn("[Chat API] Failed to normalize direct detail replacement output:", {
                      referenceLabel: reference.label,
                      referenceImageUrl: reference.imageUrl,
                      resultImageUrl: firstImage.originalUrl,
                      error:
                        normalizeError instanceof Error
                          ? normalizeError.message
                          : "unknown",
                    });
                }

                await emitReplacementResultMessage({
                  reference,
                  image: finalImage,
                  imageSizeLabel: finalImageSizeLabel,
                  modelDisplayName: resolvedModelDisplayName,
                  sourceImageUrls: Array.from(
                    new Set([
                      ...productInputImageUrls,
                      ...(modelInputImageUrl ? [modelInputImageUrl] : []),
                      ...replacementReferences.map((item) => item.imageUrl),
                    ]),
                  ),
                  streamLabel: "agent-mode:image:detail-replacement:item",
                  promptForPersistence: replacementPrompt,
                });
                successCount += 1;
              } catch (replacementItemError) {
                chatApiLogger.error("[Chat API] Direct detail replacement item failed:", {
                  referenceIndex,
                  referenceLabel: reference.label,
                  error: replacementItemError,
                });
                await emitReplacementResultMessage({
                  reference,
                  bodyText: `生成失败，当前先沿用参考图：${
                    replacementItemError instanceof Error
                      ? replacementItemError.message
                      : "请稍后重试"
                  }`,
                  image: {
                    originalUrl: reference.imageUrl,
                    thumbnailUrl: reference.imageUrl,
                  },
                  modelDisplayName: null,
                  sourceImageUrls: referenceSourceImageUrls,
                  streamLabel: "agent-mode:image:detail-replacement:item-fallback",
                });
                successCount += 1;
              }
            });
          } finally {
            stopKeepalive();
          }

          if (contextPayload?.source === "canvas") {
            writeImageGenerationStatusChunk(
              writer,
              {
                phase: successCount > 0 ? "completed" : "failed",
                modelName: resolvedModelDisplayName,
                imageCount: successCount,
              },
              "agent-mode:detail-replacement:status-finished",
            );
          }
          writeAssistantTextChunk(
            writer,
            "<!-- IMAGE_GENERATION_END -->",
            "agent-mode:detail-replacement:end",
          );
        },
      });

      return createSseResponse(directDetailReplacementStream);
    }

    if (agentPresetId) {
      const selectedAgentPreset = await getAccessibleAgentPresetById({
        id: agentPresetId,
        userId: session.user.id,
      });

      if (!selectedAgentPreset) {
        return NextResponse.json(
          {
            code: "not_found:chat",
            message: "风格化不存在或无权使用",
          },
          { status: 404 },
        );
      }

      if (selectedAgentPreset.type === "text") {
        // 生文风格化走常规多模态对话链路：
        // - 模型已由前端切到风格化预设模型
        // - 提示词通过 hiddenPrompt 注入
        // - 图片输入沿用普通多模态附件
      } else {

      const orderedSlots = [...(selectedAgentPreset.slots || [])].sort(
        (left, right) => left.slotIndex - right.slotIndex,
      );
      const presetModeConfig = normalizeAgentPresetModeConfig(selectedAgentPreset.defaultParams);
      const isSceneGenerationPreset =
        selectedAgentPreset.type === "image" &&
        presetModeConfig.modeType === "scene_generation";
      const isDetailReplacementPreset =
        selectedAgentPreset.type === "image" &&
        presetModeConfig.modeType === "detail_replacement";
      const isSkuReplacementPreset =
        selectedAgentPreset.type === "image" &&
        presetModeConfig.modeType === "sku_replacement";
      const sceneProductSlotCount = isSceneGenerationPreset
        ? Math.max(1, presetModeConfig.scene.productImageSlotCount || 1)
        : 0;
      const sceneModelSlotEnabled = isSceneGenerationPreset
        ? presetModeConfig.scene.includeModelSlot
        : false;
      const replacementProductSlotCount = isDetailReplacementPreset
        ? presetModeConfig.detail.productImageSlotCount
        : isSkuReplacementPreset
          ? presetModeConfig.sku.productImageSlotCount
          : 0;
      const replacementModelSlotEnabled = isDetailReplacementPreset
        ? presetModeConfig.detail.includeModelSlot
        : isSkuReplacementPreset
          ? presetModeConfig.sku.includeModelSlot
          : false;
      const replacementReferences = normalizeAgentModeReferences(agentModePayload);
      const detailReplacementStrategy =
        normalizeAgentModeDetailReplacementStrategy(agentModePayload);
      const isMatchingReplacementPayload =
        (isDetailReplacementPreset && agentModePayload?.modeType === "detail_replacement") ||
        (isSkuReplacementPreset && agentModePayload?.modeType === "sku_replacement");
      if (orderedSlots.length === 0) {
        return NextResponse.json(
          {
            code: "bad_request:api",
            message: "当前风格化未配置可执行槽位",
          },
          { status: 400 },
        );
      }
      if ((isDetailReplacementPreset || isSkuReplacementPreset) && !isMatchingReplacementPayload) {
        return NextResponse.json(
          {
            code: "bad_request:api",
            message: "当前模式缺少执行上下文，请返回第二步重新选择参考图后再试",
          },
          { status: 400 },
        );
      }
      if ((isDetailReplacementPreset || isSkuReplacementPreset) && replacementReferences.length === 0) {
        return NextResponse.json(
          {
            code: "bad_request:api",
            message: isDetailReplacementPreset
              ? "详情替换模式至少需要 1 张详情参考图"
              : "SKU替换模式至少需要 1 张 SKU 参考图",
          },
          { status: 400 },
        );
      }

      const uploadedImageParts = extractCurrentMessageImageParts(message.parts as any[]);
      const requiredUploadCount = getAgentRequiredUploadCount({
        presetType: selectedAgentPreset.type,
        defaultParams: selectedAgentPreset.defaultParams || null,
        fallback: 3,
      });

      if (uploadedImageParts.length < requiredUploadCount) {
        return NextResponse.json(
          {
            code: "bad_request:api",
            message: `当前风格化需要上传 ${requiredUploadCount} 张图片`,
          },
          { status: 400 },
        );
      }

      const presetModelId = String(selectedAgentPreset.defaultModelId || "").trim();
      if (!presetModelId) {
        return NextResponse.json(
          {
            code: "bad_request:api",
            message: "当前风格化未配置默认模型",
          },
          { status: 400 },
        );
      }

      const sanitizedUserSupplementPrompt = normalizeAgentSupplementPrompt(
        requestTextContent,
        selectedAgentPreset.name,
      );

      const presetSnapshot = await createAgentPresetExecutionSnapshot({
        presetId: selectedAgentPreset.id,
        userId: session.user.id,
        projectId: contextPayload?.projectId || null,
        chatId: id,
        messageId: message.id,
        presetName: selectedAgentPreset.name,
        presetType: selectedAgentPreset.type,
        visibility: selectedAgentPreset.visibility,
        categoryId: selectedAgentPreset.category?.id || selectedAgentPreset.categoryId || null,
        categoryName: selectedAgentPreset.category?.name || null,
        promptTemplate: selectedAgentPreset.promptTemplate,
        defaultModelId: selectedAgentPreset.defaultModelId || null,
        resolvedModelId: presetModelId,
        defaultParams: selectedAgentPreset.defaultParams || null,
        slotCount: orderedSlots.length,
        requiredUploadCount,
        slots: orderedSlots.map((slot) => ({
          slotIndex: slot.slotIndex,
          title: slot.title || null,
          promptTemplate: slot.promptTemplate,
          defaultParams: slot.defaultParams || null,
          requireUpload: slot.requireUpload !== false,
          uploadLabel: slot.uploadLabel || null,
          referenceAssetIds: slot.referenceAssetIds || [],
          referenceImageUrls: (slot.referenceAssets || [])
            .map((asset) => String(asset.originalUrl || "").trim())
            .filter(Boolean),
        })),
        referenceAssetIds: orderedSlots.flatMap((slot) => slot.referenceAssetIds || []),
        referenceImageUrls: orderedSlots.flatMap((slot) =>
          (slot.referenceAssets || [])
            .map((asset) => String(asset.originalUrl || "").trim())
            .filter(Boolean),
        ),
        userInputText: sanitizedUserSupplementPrompt || null,
        requestPayload: {
          selectedChatModel,
          agentPresetId,
          requiredUploadCount,
          uploadedImageUrls: uploadedImageParts.map((part) => part.url),
          agentModePayload:
            isDetailReplacementPreset || isSkuReplacementPreset
              ? {
                  modeType: agentModePayload?.modeType || null,
                  replacementStrategy: agentModePayload?.replacementStrategy || null,
                  query: agentModePayload?.query || null,
                  queryType: agentModePayload?.queryType || null,
                  selectedCandidateId: agentModePayload?.selectedCandidateId || null,
                  referenceCount: replacementReferences.length,
                }
              : null,
        },
      });

      try {
        await db
          .update(agentPresetTable)
          .set({
            usageCount: sql`${agentPresetTable.usageCount} + 1`,
            lastUsedAt: new Date(),
            updatedAt: new Date(),
          })
          .where(eq(agentPresetTable.id, selectedAgentPreset.id));
      } catch (agentUsageError) {
        chatApiLogger.warn("[Chat API] Failed to update agent preset usage stats:", agentUsageError);
      }

      const agentSequenceStream = createUIMessageStream({
        execute: async ({ writer }) => {
          if (selectedAgentPreset.type === "image") {
            writeAssistantTextChunk(
              writer,
              "<!-- IMAGE_GENERATION_START -->",
              "agent-preset:image:start",
            );
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "processing",
                  modelName:
                    selectedAgentPreset.defaultModel?.displayName ||
                    selectedAgentPreset.name,
                  imageCount: isSceneGenerationPreset
                    ? Math.max(1, effectiveImageParams?.imageCount || 1)
                    : isDetailReplacementPreset || isSkuReplacementPreset
                      ? replacementReferences.length
                    : orderedSlots.length,
                },
                "agent-preset:image:status-processing",
              );
            }
          }

          let successCount = 0;
          const sharedUploadedImageUrls = uploadedImageParts
            .map((part) => part.url)
            .filter((url) => /^https?:\/\//i.test(url));
          const sharedUploadedAssetIds = uploadedImageParts
            .map((part) => part.assetId)
            .filter((assetId): assetId is string => Boolean(assetId));

          if (
            selectedAgentPreset.type === "image" &&
            (isDetailReplacementPreset || isSkuReplacementPreset)
          ) {
            const replacementSlot = orderedSlots[0];
            const replacementTemplateReferenceImageUrls = Array.from(
              new Set(
                (replacementSlot?.referenceAssets || [])
                  .map((asset) => String(asset.originalUrl || "").trim())
                  .filter(Boolean),
              ),
            );
            const productInputImageUrls = sharedUploadedImageUrls.slice(
              0,
              Math.max(1, replacementProductSlotCount)
            );
            const modelInputImageUrl = replacementModelSlotEnabled
              ? sharedUploadedImageUrls[Math.max(0, replacementProductSlotCount)] || null
              : null;
            const sourceAssetIds = Array.from(
              new Set(
                [
                  ...sharedUploadedAssetIds,
                  ...(replacementSlot?.referenceAssetIds || []),
                ].filter(Boolean),
              ),
            );
            const baseReplacementPrompt = buildAgentSlotPrompt({
              workflowPrompt:
                isDetailReplacementPreset &&
                detailReplacementStrategy === "product_only"
                  ? null
                  : hiddenPromptText || null,
              slotPrompt:
                isDetailReplacementPreset &&
                detailReplacementStrategy === "product_only"
                  ? ""
                  : replacementSlot?.promptTemplate || selectedAgentPreset.promptTemplate,
              slotTitle: selectedAgentPreset.name,
              userSupplementPrompt:
                isDetailReplacementPreset &&
                detailReplacementStrategy === "product_only"
                  ? null
                  : sanitizedUserSupplementPrompt || null,
              includeSlotTitle: false,
              modeType: isDetailReplacementPreset
                ? "detail_replacement"
                : isSkuReplacementPreset
                  ? "sku_replacement"
                  : "generic",
            });

            if (productInputImageUrls.length === 0) {
              throw new Error("替换模式至少需要 1 张输入商品图");
            }

            const mergedImageParams = {
              ...(selectedAgentPreset.defaultParams || {}),
              ...(replacementSlot?.defaultParams || {}),
            } as Record<string, any>;
            const resolvedModelRef =
              String(selectedChatModel || "").trim() &&
              String(selectedChatModel || "").trim() !== "auto"
                ? String(selectedChatModel || "").trim()
                : presetModelId;
            const configuredReplacementAspectRatio =
              typeof mergedImageParams.aspectRatio === "string"
                ? mergedImageParams.aspectRatio
                : effectiveImageParams?.aspectRatio || defaultImageQualityParams.aspectRatio;
            const resolvedAspectRatio = "auto";
            const resolvedImageSize =
              typeof mergedImageParams.imageSize === "string"
                ? mergedImageParams.imageSize
                : effectiveImageParams?.imageSize || defaultImageQualityParams.imageSize;
            let resolvedModelDisplayName =
              selectedAgentPreset.defaultModel?.displayName || selectedAgentPreset.name;
            if (
              configuredReplacementAspectRatio &&
              configuredReplacementAspectRatio !== "auto"
            ) {
              chatApiLogger.info("[Chat API] Replacement mode forced aspect ratio to auto to preserve reference canvas:", {
                  configuredAspectRatio: configuredReplacementAspectRatio,
                });
            }
            const replacementVisionModels = await getEnabledAiModelsWithProvider().catch(
              (error) => {
                chatApiLogger.warn("[Chat API] Failed to load configured vision models for replacement analysis:", error);
                return undefined;
              },
            );
            const replacementScenePlanningRuntime =
              await resolveReplacementScenePlanningRuntime({
                models: replacementVisionModels,
              });
            const replacementScenePlanningTimeoutMs =
              replacementScenePlanningRuntime?.kind === "local_moonshot"
                ? 90_000
                : 45_000;
            chatApiLogger.info("[Chat API] Replacement scene planning runtime:", {
              kind: replacementScenePlanningRuntime?.kind || "none",
              modelName: replacementScenePlanningRuntime?.modelName || null,
              timeoutMs: replacementScenePlanningTimeoutMs,
            });
            const stopKeepalive = startStreamKeepalive(
              writer,
              "agent-preset:replacement",
              12_000,
            );
            const emitReplacementResultMessage = async (params: {
              reference: (typeof replacementReferences)[number];
              bodyText?: string | null;
              image: {
                originalUrl: string;
                thumbnailUrl?: string | null;
              };
              imageSizeLabel?: string | null;
              modelDisplayName?: string | null;
              sourceImageUrls: string[];
              sourceType: "detail_replacement" | "sku_replacement";
              streamLabel: string;
            }) => {
              const persistedImageSize =
                String(params.imageSizeLabel || "").trim() || resolvedImageSize;
              const assistantText = prependImageModelBadge(
                [
                  `<!-- AGENT_REPLACEMENT_CARD_ID:${String(params.reference.id || "").trim()} -->`,
                  `### ${params.reference.label}`,
                  String(params.bodyText || "").trim(),
                  buildAgentToolImagesMarkdown([
                    {
                      originalUrl: params.image.originalUrl,
                      thumbnailUrl: params.image.thumbnailUrl,
                      imageSize: persistedImageSize,
                    },
                  ]),
                ]
                  .filter(Boolean)
                  .join("\n\n"),
                params.modelDisplayName || null,
              );
              const assistantMessageId = generateUUID();

              await saveMessages({
                messages: [
                  {
                    id: assistantMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: assistantText }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });

              await saveGeneratedImages(
                assistantText,
                session.user.id,
                id,
                assistantMessageId,
                baseReplacementPrompt || selectedAgentPreset.name,
                resolvedModelRef,
                {
                  sourceAssetIds,
                  sourceImageUrls: params.sourceImageUrls,
                  relationType: "edited_from",
                  sourceType: params.sourceType,
                  projectId: contextPayload?.projectId || null,
                  userPrompt: requestTextContent,
                  optimizedPrompt: baseReplacementPrompt || undefined,
                  requestedImageCount: 1,
                  aspectRatio: resolvedAspectRatio,
                  imageSize: persistedImageSize,
                },
              );

              writeAssistantTextChunk(
                writer,
                assistantText,
                params.streamLabel,
                assistantMessageId,
              );

              if (contextPayload?.source === "canvas") {
                writeCanvasMediaChunk(
                  writer,
                  {
                    messageId: assistantMessageId,
                    imageUrls: [params.image.originalUrl],
                    prompt: baseReplacementPrompt || selectedAgentPreset.name,
                    sourceImageUrls: params.sourceImageUrls,
                    agentPresetId: selectedAgentPreset.id,
                    agentPresetName: selectedAgentPreset.name,
                    agentCategoryId:
                      selectedAgentPreset.category?.id ||
                      selectedAgentPreset.categoryId ||
                      null,
                    agentCategoryName: selectedAgentPreset.category?.name || null,
                    agentExecutionSnapshotId: presetSnapshot.id,
                  },
                  `${params.streamLabel}:canvas-media`,
                );
              }
            };

            try {
              await runBoundedParallel(
                Array.from(replacementReferences.entries()),
                AGENT_REPLACEMENT_PARALLEL_WORKER_COUNT,
                async ([referenceIndex, reference]) => {
                if (reference.passthrough === true) {
                  const replacementSourceType = isDetailReplacementPreset
                    ? "detail_replacement"
                    : "sku_replacement";
                  const referenceSourceImageUrls = Array.from(
                    new Set([
                      ...sharedUploadedImageUrls,
                      ...replacementTemplateReferenceImageUrls,
                      reference.imageUrl,
                    ]),
                  );
                  await emitReplacementResultMessage({
                    reference,
                    bodyText: "已按人工标记沿用参考图，直接应用当前切片，不参与继续生成。",
                    image: {
                      originalUrl: reference.imageUrl,
                      thumbnailUrl: reference.imageUrl,
                    },
                    modelDisplayName: null,
                    sourceImageUrls: referenceSourceImageUrls,
                    sourceType: replacementSourceType,
                    streamLabel: isDetailReplacementPreset
                      ? "agent-preset:image:detail-replacement:item-passthrough"
                      : "agent-preset:image:sku-replacement:item-passthrough",
                  });
                  successCount += 1;
                  return;
                }

                const pairedProductIndex =
                  isSkuReplacementPreset && productInputImageUrls.length > 0
                    ? Math.min(
                        typeof reference.assignedProductIndex === "number"
                          ? reference.assignedProductIndex
                          : referenceIndex,
                        productInputImageUrls.length - 1
                      )
                    : undefined;
                const orderedProductContextImageUrls =
                  pairedProductIndex !== undefined
                    ? [
                        productInputImageUrls[pairedProductIndex]!,
                        ...productInputImageUrls.filter(
                          (_, productIndex) => productIndex !== pairedProductIndex
                        ),
                      ]
                    : productInputImageUrls;
                const replacementExecutionPlan = await analyzeReplacementExecutionPlan({
                  modeType: isDetailReplacementPreset ? "detail_replacement" : "sku_replacement",
                  replacementStrategy:
                    isDetailReplacementPreset ? detailReplacementStrategy : undefined,
                  referenceImageUrl: reference.imageUrl,
                  referenceLabel: reference.label,
                  productImageUrls: orderedProductContextImageUrls,
                  modelImageUrl: modelInputImageUrl,
                  workflowPrompt:
                    isDetailReplacementPreset &&
                    detailReplacementStrategy === "product_only"
                      ? null
                      : baseReplacementPrompt || hiddenPromptText || null,
                  planningRuntime: replacementScenePlanningRuntime,
                  models: replacementVisionModels,
                });
                const replacementSourceType = isDetailReplacementPreset
                  ? "detail_replacement"
                  : "sku_replacement";
                chatApiLogger.info("[Chat API] Replacement reference decision:", {
                  mode: replacementSourceType,
                  referenceIndex: referenceIndex + 1,
                  totalReferences: replacementReferences.length,
                  referenceLabel: reference.label,
                  referenceImageUrl: reference.imageUrl,
                  pairedProductIndex:
                    typeof pairedProductIndex === "number" ? pairedProductIndex + 1 : null,
                  shouldReplace: replacementExecutionPlan.shouldReplace,
                  reason: replacementExecutionPlan.reason,
                  detectionModelName: replacementExecutionPlan.detectionModelName,
                  detectionSource: replacementExecutionPlan.detectionSource,
                  scenePlanSource: replacementExecutionPlan.scenePlan.analysisSource,
                  selectedProductImageIndexes:
                    replacementExecutionPlan.scenePlan.selectedProductImageIndexes,
                  useModelImage: replacementExecutionPlan.scenePlan.useModelImage,
                });
                chatApiLogger.info("[Chat API] Replacement scene plan summary:", {
                  mode: replacementSourceType,
                  referenceIndex: referenceIndex + 1,
                  referenceLabel: reference.label,
                  analysisModelName: replacementExecutionPlan.scenePlan.analysisModelName,
                  analysisSource: replacementExecutionPlan.scenePlan.analysisSource,
                  selectedProductImageIndexes:
                    replacementExecutionPlan.scenePlan.selectedProductImageIndexes,
                  productSelectionReason:
                    replacementExecutionPlan.scenePlan.productSelectionReason,
                  useModelImage: replacementExecutionPlan.scenePlan.useModelImage,
                  modelImageReason: replacementExecutionPlan.scenePlan.modelImageReason,
                });
                const referenceSourceImageUrls = Array.from(
                  new Set([
                    ...sharedUploadedImageUrls,
                    ...replacementTemplateReferenceImageUrls,
                    reference.imageUrl,
                  ]),
                );

                if (!replacementExecutionPlan.shouldReplace) {
                  chatApiLogger.info("[Chat API] Replacement reference skipped and reused:", {
                    mode: replacementSourceType,
                    referenceIndex: referenceIndex + 1,
                    totalReferences: replacementReferences.length,
                    referenceLabel: reference.label,
                    reason: replacementExecutionPlan.reason,
                  });
                  await emitReplacementResultMessage({
                    reference,
                    bodyText: replacementExecutionPlan.reason,
                    image: {
                      originalUrl: reference.imageUrl,
                      thumbnailUrl: reference.imageUrl,
                    },
                    modelDisplayName: null,
                    sourceImageUrls: referenceSourceImageUrls,
                    sourceType: replacementSourceType,
                    streamLabel: isDetailReplacementPreset
                      ? "agent-preset:image:detail-replacement:item"
                      : "agent-preset:image:sku-replacement:item",
                  });
                  successCount += 1;
                  return;
                }

                const referenceGeometry = await resolveReplacementReferenceGeometry(reference.imageUrl);
                const generationAspectRatio = referenceGeometry?.aspectRatio || resolvedAspectRatio;
                const selectedProductIndexes = replacementExecutionPlan.scenePlan
                  .selectedProductImageIndexes.map((index) => index - 1)
                  .filter(
                    (index) =>
                      index >= 0 && index < orderedProductContextImageUrls.length,
                  );
                const selectedProductContextImageUrls =
                  selectedProductIndexes.length > 0
                    ? selectedProductIndexes.map(
                        (index) => orderedProductContextImageUrls[index]!,
                      )
                    : orderedProductContextImageUrls.slice(
                        0,
                        Math.min(orderedProductContextImageUrls.length, 2),
                      );
                const sourceImageUrls = Array.from(
                  new Set(
                    [
                      ...selectedProductContextImageUrls,
                      ...(replacementExecutionPlan.scenePlan.useModelImage &&
                      !(isDetailReplacementPreset &&
                        detailReplacementStrategy === "product_only") &&
                      modelInputImageUrl
                        ? [modelInputImageUrl]
                        : []),
                      ...replacementTemplateReferenceImageUrls,
                      reference.imageUrl,
                    ].filter(Boolean),
                  ),
                );
                const replacementPrompt = buildAgentReplacementPrompt({
                  basePrompt:
                    baseReplacementPrompt ||
                    (isDetailReplacementPreset ? "执行详情替换" : "执行 SKU 替换"),
                  modeType: isDetailReplacementPreset
                    ? "detail_replacement"
                    : "sku_replacement",
                  replacementStrategy:
                    isDetailReplacementPreset ? detailReplacementStrategy : undefined,
                  referenceLabel: reference.label,
                  referenceIndex,
                  totalReferences: replacementReferences.length,
                  hasModelImage:
                    replacementExecutionPlan.scenePlan.useModelImage &&
                    !(isDetailReplacementPreset &&
                      detailReplacementStrategy === "product_only") &&
                    Boolean(modelInputImageUrl),
                  productImageCount: selectedProductContextImageUrls.length,
                  originalProductImageCount: productInputImageUrls.length,
                  templateReferenceCount: replacementTemplateReferenceImageUrls.length,
                  pairedProductIndex,
                  scenePlan: replacementExecutionPlan.scenePlan,
                  referenceGeometry,
                });
                chatApiLogger.info("[Chat API] Replacement image generation started:", {
                  mode: replacementSourceType,
                  referenceIndex: referenceIndex + 1,
                  totalReferences: replacementReferences.length,
                  referenceLabel: reference.label,
                  pairedProductIndex:
                    typeof pairedProductIndex === "number" ? pairedProductIndex + 1 : null,
                  sourceImageCount: sourceImageUrls.length,
                  generationAspectRatio,
                  imageOrder: {
                    productImages: selectedProductContextImageUrls.length,
                    originalProductImages: productInputImageUrls.length,
                    hasModelImage:
                      replacementExecutionPlan.scenePlan.useModelImage &&
                      Boolean(modelInputImageUrl),
                    templateReferenceImages: replacementTemplateReferenceImageUrls.length,
                    finalReferenceImageIndex: sourceImageUrls.length,
                  },
                });

                try {
                  const result = await generateCanvasImage({
                    prompt: replacementPrompt,
                    negativePrompt:
                      typeof mergedImageParams.negativePrompt === "string"
                        ? mergedImageParams.negativePrompt
                        : undefined,
                    model: resolvedModelRef,
                    ownerKey: session.user.id,
                    aspectRatio: generationAspectRatio,
                    imageSize: resolvedImageSize,
                    imageCount: 1,
                    referenceImages: sourceImageUrls,
                    debugLabel: `agent-${replacementSourceType}`,
                    debugMeta: {
                      referenceLabel: reference.label,
                      referenceWidth: referenceGeometry?.width,
                      referenceHeight: referenceGeometry?.height,
                      referenceAspectRatio: referenceGeometry?.aspectRatio,
                    },
                    onQueueStatusChange:
                      contextPayload?.source === "canvas"
                        ? async (queueStatus) => {
                            writeImageGenerationStatusChunk(
                              writer,
                              {
                                phase:
                                  queueStatus.status === "running"
                                    ? "processing"
                                    : "queued",
                                modelName:
                                  queueStatus.modelName ||
                                  resolvedModelDisplayName ||
                                  resolvedModelRef,
                                imageCount: 1,
                                queuePosition: queueStatus.queuePosition,
                                sameModelRunningCount: queueStatus.sameModelRunningCount,
                                concurrencyLimit: queueStatus.concurrencyLimit,
                                estimatedWaitMs: queueStatus.estimatedWaitMs,
                              },
                              `agent-preset:replacement:queue:${reference.id}`,
                            );
                          }
                        : undefined,
                  });
                  resolvedModelDisplayName = result.model || resolvedModelDisplayName;
                  const firstImage = result.images[0];
                  if (!firstImage) {
                    throw new Error("未返回结果图片");
                  }
                  let finalImage = firstImage;
                  let finalImageSizeLabel = resolvedImageSize;
                  try {
                    const normalizedImage = await normalizeReplacementResultImage({
                      generatedImageUrl: firstImage.originalUrl,
                      generatedThumbnailUrl: firstImage.thumbnailUrl,
                      referenceImageUrl: reference.imageUrl,
                      referenceGeometry,
                      uploadPrefix: isDetailReplacementPreset
                        ? "agent-detail-replacement"
                        : "agent-sku-replacement",
                    });
                    finalImage = {
                      originalUrl: normalizedImage.originalUrl,
                      thumbnailUrl: normalizedImage.thumbnailUrl,
                    };
                    finalImageSizeLabel = normalizedImage.imageSize;
                  } catch (normalizeError) {
                    chatApiLogger.warn("[Chat API] Failed to normalize replacement output to reference size, using original model output:", {
                        referenceLabel: reference.label,
                        referenceImageUrl: reference.imageUrl,
                        resultImageUrl: firstImage.originalUrl,
                        error:
                          normalizeError instanceof Error
                            ? normalizeError.message
                            : "unknown",
                      });
                  }
                  chatApiLogger.info("[Chat API] Replacement image generation completed:", {
                    mode: replacementSourceType,
                    referenceIndex: referenceIndex + 1,
                    totalReferences: replacementReferences.length,
                    referenceLabel: reference.label,
                    modelDisplayName: resolvedModelDisplayName,
                    resultImageUrl: finalImage.originalUrl,
                    resultImageSize: finalImageSizeLabel,
                  });
                  await emitReplacementResultMessage({
                    reference,
                    image: finalImage,
                    imageSizeLabel: finalImageSizeLabel,
                    modelDisplayName: resolvedModelDisplayName,
                    sourceImageUrls: Array.from(
                      new Set([
                        ...sharedUploadedImageUrls,
                        ...replacementTemplateReferenceImageUrls,
                        ...replacementReferences.map((item) => item.imageUrl),
                      ]),
                    ),
                    sourceType: replacementSourceType,
                    streamLabel: isDetailReplacementPreset
                      ? "agent-preset:image:detail-replacement:item"
                      : "agent-preset:image:sku-replacement:item",
                  });
                  successCount += 1;
                } catch (replacementItemError) {
                  chatApiLogger.error("[Chat API] Agent replacement item execution failed:", {
                    referenceIndex,
                    referenceLabel: reference.label,
                    error: replacementItemError,
                  });
                  await emitReplacementResultMessage({
                    reference,
                    bodyText: `生成失败，当前先沿用参考图：${
                      replacementItemError instanceof Error
                        ? replacementItemError.message
                        : "请稍后重试"
                    }`,
                    image: {
                      originalUrl: reference.imageUrl,
                      thumbnailUrl: reference.imageUrl,
                    },
                    modelDisplayName: null,
                    sourceImageUrls: referenceSourceImageUrls,
                    sourceType: replacementSourceType,
                    streamLabel: isDetailReplacementPreset
                      ? "agent-preset:image:detail-replacement:item-fallback"
                      : "agent-preset:image:sku-replacement:item-fallback",
                  });
                  successCount += 1;
                }
              });
            } finally {
              stopKeepalive();
            }
          } else if (selectedAgentPreset.type === "image" && isSceneGenerationPreset) {
            const sceneSlot = orderedSlots[0];
            const sceneAssistantMessageId = generateUUID();
            const sceneReferenceImageUrls = Array.from(
              new Set(
                (sceneSlot?.referenceAssets || [])
                  .map((asset) => String(asset.originalUrl || "").trim())
                  .filter(Boolean),
              ),
            );
            const sourceImageUrls = Array.from(
              new Set([...sharedUploadedImageUrls, ...sceneReferenceImageUrls].filter(Boolean)),
            );
            const sourceAssetIds = Array.from(
              new Set(
                [...sharedUploadedAssetIds, ...(sceneSlot?.referenceAssetIds || [])].filter(Boolean),
              ),
            );
            const sceneUploadedImageBreakdown = getSceneUploadedImageBreakdown({
              uploadedImageParts,
              fallbackPrimaryCount: sceneProductSlotCount,
              fallbackIncludeModelImage: sceneModelSlotEnabled,
            });
            const sceneImageRolePrompt = buildAgentSceneImageRolePrompt({
              primaryProductImageCount: sceneUploadedImageBreakdown.primaryProductImageCount,
              bundleProductImageCount: sceneUploadedImageBreakdown.bundleProductImageCount,
              includeModelImage: sceneUploadedImageBreakdown.includeModelImage,
            });
            const sceneOptimizationImageUrls = resolveScenePromptOptimizationImageUrls({
              uploadedImageParts,
              primaryProductImageCount: sceneUploadedImageBreakdown.primaryProductImageCount,
              bundleProductImageCount: sceneUploadedImageBreakdown.bundleProductImageCount,
              includeModelImage: sceneUploadedImageBreakdown.includeModelImage,
            });
            const shouldAppendSceneSlotPrompt = !hiddenPromptText;
            const rawSceneSlotPrompt = shouldAppendSceneSlotPrompt
              ? sceneSlot?.promptTemplate || selectedAgentPreset.promptTemplate || ""
              : "";
            const dedupedSceneSlotPrompt = rawSceneSlotPrompt
              ? dedupeAgentSlotPromptAgainstWorkflow({
                  workflowPrompt: hiddenPromptText || null,
                  slotPrompt: rawSceneSlotPrompt,
                  modeType: "scene_generation",
                })
              : "";
            const optimizedSceneWorkflowResult =
              workflowPromptOptimizationEnabled !== false &&
              hiddenPromptText &&
              sceneOptimizationImageUrls.primaryImageUrl
                ? await optimizeAgentSceneWorkflowPrompt({
                    workflowPrompt: hiddenPromptText,
                    slotPrompt: dedupedSceneSlotPrompt || null,
                    primaryImageUrl: sceneOptimizationImageUrls.primaryImageUrl,
                    modelImageUrl: sceneOptimizationImageUrls.modelImageUrl,
                  }).catch((error) => {
                    chatApiLogger.warn("[Chat API] Agent scene workflow prompt optimization failed:", error);
                    return null;
                  })
                : null;
            const optimizedSceneWorkflowPrompt = hiddenPromptText
              ? buildOptimizedAgentSceneWorkflowPrompt({
                  workflowPrompt: hiddenPromptText,
                  optimizationResult: optimizedSceneWorkflowResult,
                })
              : "";
            if (optimizedSceneWorkflowResult) {
              chatApiLogger.info("[Chat API] Agent scene workflow prompt optimized:", {
                chatId: id,
                agentPresetId: selectedAgentPreset.id,
                optimizationModelName: optimizedSceneWorkflowResult.optimizationModelName || null,
                optimizationSource: optimizedSceneWorkflowResult.optimizationSource || null,
                sceneGoal: optimizedSceneWorkflowResult.sceneGoal,
                environmentSummary: optimizedSceneWorkflowResult.environmentSummary,
                cameraLightingSummary: optimizedSceneWorkflowResult.cameraLightingSummary,
                characterSummary: optimizedSceneWorkflowResult.characterSummary,
                negativeConstraints: optimizedSceneWorkflowResult.negativeConstraints,
                conflicts: optimizedSceneWorkflowResult.conflicts,
              });
            } else if (hiddenPromptText && workflowPromptOptimizationEnabled === false) {
              chatApiLogger.info("[Chat API] Agent scene workflow prompt optimization skipped:", {
                chatId: id,
                agentPresetId: selectedAgentPreset.id,
                reason: "workflow_prompt_optimization_disabled",
              });
            }
            const scenePrompt =
              buildAgentSceneWorkflowPrompt({
                workflowPrompt: optimizedSceneWorkflowPrompt || hiddenPromptText || null,
                slotPrompt: optimizedSceneWorkflowPrompt ? null : dedupedSceneSlotPrompt || null,
                imageRolePrompt: sceneImageRolePrompt,
                userSupplementPrompt: sanitizedUserSupplementPrompt || null,
              }) ||
              buildAgentSlotPrompt({
              workflowPrompt: hiddenPromptText || null,
              slotPrompt: sceneSlot?.promptTemplate || selectedAgentPreset.promptTemplate,
              userSupplementPrompt: sanitizedUserSupplementPrompt || null,
              includeSlotTitle: false,
              modeType: "scene_generation",
              });
            const sceneGenerationStartedAt = Date.now();
            chatApiLogger.info("[Chat API] Agent scene prompt guardrails:", {
              chatId: id,
              agentPresetId: selectedAgentPreset.id,
              agentPresetName: selectedAgentPreset.name,
              agentExecutionSnapshotId: presetSnapshot.id,
              includesWorkflowPrompt: Boolean(hiddenPromptText),
              includesUserSupplementPrompt: Boolean(sanitizedUserSupplementPrompt),
              includesModelImage: sceneUploadedImageBreakdown.includeModelImage,
              shouldAppendSceneSlotPrompt,
              includesSceneSlotPrompt: Boolean(dedupedSceneSlotPrompt),
              productImageCount: sceneUploadedImageBreakdown.primaryProductImageCount,
              bundleImageCount: sceneUploadedImageBreakdown.bundleProductImageCount,
              uploadedImageCount: sharedUploadedImageUrls.length,
              hasProductIdentityLock: sceneImageRolePrompt.includes("【产品锁定约束】"),
              hasModelIdentityLock: sceneImageRolePrompt.includes("【模特锁定约束】"),
              hasModelClothingOverrideRule: sceneImageRolePrompt.includes(
                "只有当工作流设定或补充要求里明确要求修改模特衣服"
              ),
              sceneSlotPromptPreview: dedupedSceneSlotPrompt
                .split("\n")
                .map((line) => line.trim())
                .filter(Boolean)
                .slice(0, 10),
              imageRolePreview: sceneImageRolePrompt
                .split("\n")
                .map((line) => line.trim())
                .filter(Boolean)
                .slice(0, 12),
            });

            try {
              const mergedImageParams = {
                ...(selectedAgentPreset.defaultParams || {}),
                ...(sceneSlot?.defaultParams || {}),
              } as Record<string, any>;
              const resolvedModelRef =
                presetModeConfig.scene.allowModelOverride &&
                String(selectedChatModel || "").trim() &&
                String(selectedChatModel || "").trim() !== "auto"
                  ? String(selectedChatModel || "").trim()
                  : presetModelId;
              const resolvedImageCount = Math.max(1, effectiveImageParams?.imageCount || 1);
              chatApiLogger.info("[Chat API] Agent scene generation started:", {
                chatId: id,
                agentPresetId: selectedAgentPreset.id,
                agentPresetName: selectedAgentPreset.name,
                agentExecutionSnapshotId: presetSnapshot.id,
                projectId: contextPayload?.projectId || null,
                selectedChatModel: String(selectedChatModel || "").trim() || "auto",
                resolvedModelRef,
                resolvedImageCount,
                sourceImageCount: sourceImageUrls.length,
                sourceAssetCount: sourceAssetIds.length,
                promptStrategy: hiddenPromptText
                  ? "workflow_plus_image_lock"
                  : rawSceneSlotPrompt
                    ? "legacy_template_fallback"
                    : sanitizedUserSupplementPrompt
                      ? "workflow_plus_user_supplement"
                      : "workflow_only",
                promptLength: String(scenePrompt || `生成${selectedAgentPreset.name}`).length,
                aspectRatio:
                  typeof mergedImageParams.aspectRatio === "string"
                    ? mergedImageParams.aspectRatio
                    : effectiveImageParams?.aspectRatio || defaultImageQualityParams.aspectRatio,
                imageSize:
                  typeof mergedImageParams.imageSize === "string"
                    ? mergedImageParams.imageSize
                    : effectiveImageParams?.imageSize || defaultImageQualityParams.imageSize,
              });
              const result = await generateCanvasImage({
                prompt: scenePrompt || `生成${selectedAgentPreset.name}`,
                negativePrompt:
                  typeof mergedImageParams.negativePrompt === "string"
                    ? mergedImageParams.negativePrompt
                    : undefined,
                model: resolvedModelRef,
                ownerKey: session.user.id,
                aspectRatio:
                  typeof mergedImageParams.aspectRatio === "string"
                    ? mergedImageParams.aspectRatio
                    : effectiveImageParams?.aspectRatio || defaultImageQualityParams.aspectRatio,
                imageSize:
                  typeof mergedImageParams.imageSize === "string"
                    ? mergedImageParams.imageSize
                    : effectiveImageParams?.imageSize || defaultImageQualityParams.imageSize,
                imageCount: resolvedImageCount,
                referenceImages: sourceImageUrls,
                debugLabel: "agent-scene-generation",
                debugMeta: {
                  chatId: id,
                  agentPresetId: selectedAgentPreset.id,
                  agentPresetName: selectedAgentPreset.name,
                  agentExecutionSnapshotId: presetSnapshot.id,
                  projectId: contextPayload?.projectId || null,
                },
                onQueueStatusChange:
                  contextPayload?.source === "canvas"
                    ? async (queueStatus) => {
                        writeImageGenerationStatusChunk(
                          writer,
                          {
                            phase:
                              queueStatus.status === "running"
                                ? "processing"
                                : "queued",
                            modelName:
                              queueStatus.modelName || selectedAgentPreset.name,
                            imageCount: resolvedImageCount,
                            queuePosition: queueStatus.queuePosition,
                            sameModelRunningCount: queueStatus.sameModelRunningCount,
                            concurrencyLimit: queueStatus.concurrencyLimit,
                            estimatedWaitMs: queueStatus.estimatedWaitMs,
                          },
                          "agent-preset:image:scene-generation:queue",
                        );
                      }
                    : undefined,
              });
              chatApiLogger.info("[Chat API] Agent scene generation model completed:", {
                chatId: id,
                agentPresetId: selectedAgentPreset.id,
                agentPresetName: selectedAgentPreset.name,
                agentExecutionSnapshotId: presetSnapshot.id,
                resultImageCount: result.images.length,
                resultModelName: result.model,
                resultModelRef: result.modelRef,
                elapsedMs: Date.now() - sceneGenerationStartedAt,
              });

              const imageMarkdown = buildAgentToolImagesMarkdown(
                result.images.map((image) => ({
                  originalUrl: image.originalUrl,
                  thumbnailUrl: image.thumbnailUrl,
                  imageSize:
                    typeof mergedImageParams.imageSize === "string"
                      ? mergedImageParams.imageSize
                      : effectiveImageParams?.imageSize || defaultImageQualityParams.imageSize,
                })),
              );
              const assistantText = prependImageModelBadge(
                [`### ${selectedAgentPreset.name}`, imageMarkdown].filter(Boolean).join("\n\n"),
                result.model,
              );

              await saveMessages({
                messages: [
                  {
                    id: sceneAssistantMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: assistantText }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });

              await saveGeneratedImages(
                assistantText,
                session.user.id,
                id,
                sceneAssistantMessageId,
                scenePrompt || selectedAgentPreset.name,
                result.modelRef || resolvedModelRef,
                {
                  sourceAssetIds,
                  sourceImageUrls,
                  relationType: "generated_from",
                  sourceType:
                    sourceImageUrls.length > 0 ? "reference_generate" : "generated",
                  projectId: contextPayload?.projectId || null,
                  userPrompt: requestTextContent,
                  optimizedPrompt: scenePrompt || undefined,
                  requestedImageCount: resolvedImageCount,
                },
              );
              chatApiLogger.info("[Chat API] Agent scene generation persisted:", {
                chatId: id,
                agentPresetId: selectedAgentPreset.id,
                agentPresetName: selectedAgentPreset.name,
                agentExecutionSnapshotId: presetSnapshot.id,
                savedImageCount: result.images.length,
                elapsedMs: Date.now() - sceneGenerationStartedAt,
              });

              writeAssistantTextChunk(
                writer,
                assistantText,
                "agent-preset:image:scene-generation",
                sceneAssistantMessageId,
              );
              if (contextPayload?.source === "canvas") {
                writeCanvasMediaChunk(
                  writer,
                  {
                    messageId: sceneAssistantMessageId,
                    imageUrls: result.images.map((image) => image.originalUrl),
                    prompt: scenePrompt || selectedAgentPreset.name,
                    sourceImageUrls,
                    agentPresetId: selectedAgentPreset.id,
                    agentPresetName: selectedAgentPreset.name,
                    agentCategoryId:
                      selectedAgentPreset.category?.id ||
                      selectedAgentPreset.categoryId ||
                      null,
                    agentCategoryName: selectedAgentPreset.category?.name || null,
                    agentExecutionSnapshotId: presetSnapshot.id,
                  },
                  "agent-preset:image:scene-generation:canvas-media",
                );
              }
              chatApiLogger.info("[Chat API] Agent scene generation response streamed:", {
                chatId: id,
                agentPresetId: selectedAgentPreset.id,
                agentPresetName: selectedAgentPreset.name,
                agentExecutionSnapshotId: presetSnapshot.id,
                resultImageCount: result.images.length,
                elapsedMs: Date.now() - sceneGenerationStartedAt,
              });

              successCount = result.images.length;
            } catch (sceneError) {
              chatApiLogger.error("[Chat API] Agent preset scene generation failed:", sceneError);
              chatApiLogger.error("[Chat API] Agent scene generation failed detail:", {
                chatId: id,
                agentPresetId: selectedAgentPreset.id,
                agentPresetName: selectedAgentPreset.name,
                agentExecutionSnapshotId: presetSnapshot.id,
                elapsedMs: Date.now() - sceneGenerationStartedAt,
                error: sceneError instanceof Error ? sceneError.message : String(sceneError),
              });
              const errorMessage = `### ${selectedAgentPreset.name}\n\n执行失败：${
                sceneError instanceof Error ? sceneError.message : "请稍后重试"
              }`;
              await saveMessages({
                messages: [
                  {
                    id: sceneAssistantMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: errorMessage }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
              writeAssistantTextChunk(
                writer,
                errorMessage,
                "agent-preset:error:scene-generation",
                sceneAssistantMessageId,
              );
            }
          } else {
          for (const [slotOrder, slot] of orderedSlots.entries()) {
            const slotLabel =
              String(slot.title || slot.uploadLabel || "").trim() || `第${slotOrder + 1}张`;
            const slotReferenceImageUrls = Array.from(
              new Set(
                (slot.referenceAssets || [])
                  .map((asset) => String(asset.originalUrl || "").trim())
                  .filter(Boolean),
              ),
            );
            const sourceImageUrls = Array.from(
              new Set(
                [
                  ...sharedUploadedImageUrls,
                  ...slotReferenceImageUrls,
                ].filter(Boolean),
              ),
            );
            const sourceAssetIds = Array.from(
              new Set(
                [
                  ...sharedUploadedAssetIds,
                  ...(slot.referenceAssetIds || []),
                ].filter(Boolean),
              ),
            );
            const slotPrompt = buildAgentSlotPrompt({
              workflowPrompt: hiddenPromptText || null,
              slotPrompt: slot.promptTemplate,
              slotTitle: slot.title || slot.uploadLabel || null,
              userSupplementPrompt: sanitizedUserSupplementPrompt || null,
              modeType: "generic",
            });
            const assistantMessageId = generateUUID();

            try {
              if (selectedAgentPreset.type === "image") {
                const mergedImageParams = {
                  ...(selectedAgentPreset.defaultParams || {}),
                  ...(slot.defaultParams || {}),
                } as Record<string, any>;
                const result = await generateCanvasImage({
                  prompt: slotPrompt || `生成${slotLabel}`,
                  negativePrompt:
                    typeof mergedImageParams.negativePrompt === "string"
                      ? mergedImageParams.negativePrompt
                      : undefined,
                  model: presetModelId,
                  ownerKey: session.user.id,
                  aspectRatio:
                    typeof mergedImageParams.aspectRatio === "string"
                      ? mergedImageParams.aspectRatio
                      : effectiveImageParams?.aspectRatio || defaultImageQualityParams.aspectRatio,
                  imageSize:
                    typeof mergedImageParams.imageSize === "string"
                      ? mergedImageParams.imageSize
                      : effectiveImageParams?.imageSize || defaultImageQualityParams.imageSize,
                  imageCount: 1,
                  referenceImages: sourceImageUrls,
                  onQueueStatusChange:
                    contextPayload?.source === "canvas"
                      ? async (queueStatus) => {
                          writeImageGenerationStatusChunk(
                            writer,
                            {
                              phase:
                                queueStatus.status === "running"
                                  ? "processing"
                                  : "queued",
                              modelName: queueStatus.modelName || slotLabel,
                              imageCount: 1,
                              queuePosition: queueStatus.queuePosition,
                              sameModelRunningCount: queueStatus.sameModelRunningCount,
                              concurrencyLimit: queueStatus.concurrencyLimit,
                              estimatedWaitMs: queueStatus.estimatedWaitMs,
                            },
                            `agent-preset:image:slot-queue:${slot.slotIndex}`,
                          );
                        }
                      : undefined,
                });

                const imageMarkdown = buildAgentToolImagesMarkdown(
                  result.images.map((image) => ({
                    originalUrl: image.originalUrl,
                    thumbnailUrl: image.thumbnailUrl,
                    imageSize:
                      typeof mergedImageParams.imageSize === "string"
                        ? mergedImageParams.imageSize
                        : effectiveImageParams?.imageSize || defaultImageQualityParams.imageSize,
                  })),
                );
                const assistantText = prependImageModelBadge(
                  [`### ${slotLabel}`, imageMarkdown].filter(Boolean).join("\n\n"),
                  result.model,
                );

                await saveMessages({
                  messages: [
                    {
                      id: assistantMessageId,
                      chatId: id,
                      role: "assistant",
                      parts: [{ type: "text", text: assistantText }],
                      attachments: [],
                      createdAt: new Date(),
                      videoStorageStatus: null,
                      temporaryVideoUrl: null,
                      permanentVideoUrl: null,
                      archivedAt: null,
                      videoMetadata: null,
                    },
                  ],
                });

                await saveGeneratedImages(
                  assistantText,
                  session.user.id,
                  id,
                  assistantMessageId,
                  slotPrompt || slotLabel,
                  result.modelRef || presetModelId,
                  {
                    sourceAssetIds,
                    sourceImageUrls,
                    relationType: "generated_from",
                    sourceType:
                      sourceImageUrls.length > 0 ? "reference_generate" : "generated",
                    projectId: contextPayload?.projectId || null,
                    userPrompt: requestTextContent,
                    optimizedPrompt: slotPrompt || undefined,
                    requestedImageCount: 1,
                  },
                );

                writeAssistantTextChunk(
                  writer,
                  assistantText,
                  `agent-preset:image:slot-${slotOrder + 1}`,
                  assistantMessageId,
                );
                if (contextPayload?.source === "canvas") {
                  writeCanvasMediaChunk(
                    writer,
                    {
                      messageId: assistantMessageId,
                      imageUrls: result.images.map((image) => image.originalUrl),
                      prompt: slotPrompt || slotLabel,
                      sourceImageUrls,
                      agentPresetId: selectedAgentPreset.id,
                      agentPresetName: selectedAgentPreset.name,
                      agentCategoryId:
                        selectedAgentPreset.category?.id ||
                        selectedAgentPreset.categoryId ||
                        null,
                      agentCategoryName: selectedAgentPreset.category?.name || null,
                      agentExecutionSnapshotId: presetSnapshot.id,
                    },
                    `agent-preset:image:slot-${slotOrder + 1}:canvas-media`,
                  );
                }
              } else {
                const mergedVideoParams = {
                  ...(selectedAgentPreset.defaultParams || {}),
                  ...(slot.defaultParams || {}),
                } as Record<string, any>;
                const requestedMode = String(mergedVideoParams.mode || "").trim() as
                  | "text-to-video"
                  | "first-frame"
                  | "first-last-frame"
                  | "reference-images";
                const mode =
                  requestedMode ||
                  (sourceImageUrls.length >= 2
                    ? "first-last-frame"
                    : sourceImageUrls.length >= 1
                      ? "first-frame"
                      : "text-to-video");
                const directVideoRatio =
                  mergedVideoParams.ratio === "16:9" ||
                  mergedVideoParams.ratio === "4:3" ||
                  mergedVideoParams.ratio === "1:1" ||
                  mergedVideoParams.ratio === "3:4" ||
                  mergedVideoParams.ratio === "9:16" ||
                  mergedVideoParams.ratio === "21:9" ||
                  mergedVideoParams.ratio === "adaptive"
                    ? mergedVideoParams.ratio
                    : undefined;
                const images =
                  mode === "first-last-frame"
                    ? sourceImageUrls.slice(0, 2)
                    : mode === "first-frame"
                      ? sourceImageUrls.slice(0, 1)
                      : mode === "reference-images"
                        ? sourceImageUrls.slice(0, 4)
                        : [];

                const result = await executeDirectVideoGeneration({
                  prompt: slotPrompt || `生成${slotLabel}`,
                  mode,
                  images,
                  resolution: mergedVideoParams.resolution,
                  ratio: directVideoRatio,
                  duration: mergedVideoParams.duration,
                  preferredModelRef: presetModelId,
                });

                const videoUrl = String(result.videoUrl || "").trim();
                if (!videoUrl) {
                  throw new Error("视频生成完成但未返回视频地址");
                }

                const assistantText = prependImageModelBadge(
                  [
                    `### ${slotLabel}`,
                    buildAgentToolVideoMarkdown(videoUrl),
                  ]
                    .filter(Boolean)
                    .join("\n\n"),
                  result.modelDisplayName,
                );

                await saveMessages({
                  messages: [
                    {
                      id: assistantMessageId,
                      chatId: id,
                      role: "assistant",
                      parts: [{ type: "text", text: assistantText }],
                      attachments: [],
                      createdAt: new Date(),
                      videoStorageStatus: "temporary",
                      temporaryVideoUrl: videoUrl,
                      permanentVideoUrl: null,
                      archivedAt: null,
                      videoMetadata: (result.metadata || {}) as any,
                    },
                  ],
                });

          try {
            await persistVideoGenerationCompletedTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              messageId: assistantMessageId,
              text: requestTextContent,
              source: "agent_preset_direct_video",
              providerType: "direct-video",
              modelRef: result.modelRef || presetModelId,
              mode,
              status: "completed",
              temporaryVideoUrl: videoUrl,
            });
          } catch (memoryError) {
                  chatApiLogger.warn("[Chat API] Failed to update working state after agent preset video generation:", memoryError);
                }

                await consumeGeneratedVideoPoints({
                  userId: session.user.id,
                  chatId: id,
                  messageId: assistantMessageId,
                  modelRefs: [result.modelRef || presetModelId],
                  duration: Number((result.metadata as any)?.duration) || undefined,
                  resolution:
                    String((result.metadata as any)?.resolution || "").trim() ||
                    undefined,
                });

                scheduleVideoArchive({
                  chatId: id,
                  messageId: assistantMessageId,
                  text: assistantText,
                  temporaryVideoUrl: videoUrl,
                  taskId: assistantMessageId,
                  metadata: result.metadata,
                });

                writeAssistantTextChunk(
                  writer,
                  assistantText,
                  `agent-preset:video:slot-${slotOrder + 1}`,
                  assistantMessageId,
                );
                if (contextPayload?.source === "canvas") {
                  writeCanvasMediaChunk(
                    writer,
                    {
                      messageId: assistantMessageId,
                      videoUrls: [videoUrl],
                      prompt: slotPrompt || slotLabel,
                      sourceImageUrls,
                      agentPresetId: selectedAgentPreset.id,
                      agentPresetName: selectedAgentPreset.name,
                      agentCategoryId:
                        selectedAgentPreset.category?.id ||
                        selectedAgentPreset.categoryId ||
                        null,
                      agentCategoryName: selectedAgentPreset.category?.name || null,
                      agentExecutionSnapshotId: presetSnapshot.id,
                    },
                    `agent-preset:video:slot-${slotOrder + 1}:canvas-media`,
                  );
                }
              }

              successCount += 1;
            } catch (slotError) {
              chatApiLogger.error("[Chat API] Agent preset slot execution failed:", {
                slotIndex: slot.slotIndex,
                slotLabel,
                error: slotError,
              });
              const errorMessage = `### ${slotLabel}\n\n执行失败：${
                slotError instanceof Error ? slotError.message : "请稍后重试"
              }`;
              await saveMessages({
                messages: [
                  {
                    id: assistantMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: errorMessage }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
              if (selectedAgentPreset.type === "video") {
                try {
                  await persistVideoGenerationFailedTurn({
                    userId: session.user.id,
                    chatId: id,
                    projectId: contextPayload?.projectId || null,
                    messageId: assistantMessageId,
                    text: requestTextContent,
                    source: "agent_preset_direct_video",
                    providerType: "direct-video",
                    modelRef: presetModelId,
                    status: "failed",
                    error: slotError instanceof Error ? slotError.message : String(slotError),
                  });
                } catch (videoMemoryError) {
                  chatApiLogger.warn("[Chat API] Failed to persist agent preset video failure state:", videoMemoryError);
                }
              }
              writeAssistantTextChunk(
                writer,
                errorMessage,
                `agent-preset:error:slot-${slotOrder + 1}`,
                assistantMessageId,
              );
            }
          }
          }

          try {
            await persistAgentPresetTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              currentIntent: selectedAgentPreset.type === "video" ? "video_gen" : "image_gen",
              lastMessageId: message.id,
              text: requestTextContent,
              agentPresetId: selectedAgentPreset.id,
              agentPresetName: selectedAgentPreset.name,
              slotCount: orderedSlots.length,
              successCount,
            });
          } catch (agentPresetMemoryError) {
            chatApiLogger.warn("[Chat API] Failed to persist agent preset working state:", agentPresetMemoryError);
          }

          if (selectedAgentPreset.type === "image") {
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: successCount > 0 ? "completed" : "failed",
                  modelName:
                    selectedAgentPreset.defaultModel?.displayName ||
                    selectedAgentPreset.name,
                  imageCount: successCount,
                },
                "agent-preset:image:status-finished",
              );
            }
            writeAssistantTextChunk(
              writer,
              "<!-- IMAGE_GENERATION_END -->",
              "agent-preset:image:end",
            );
          }
        },
      });

      return createSseResponse(agentSequenceStream);
      }
    }

    const directAgentToolContext = shouldRunAgentConversation
      ? resolveDirectAgentToolContext({
          execution: smartAutoExecution,
          plan: smartAutoPlan,
          requestResolvedMediaInput,
          requestTargetResolution,
          requestWorkingState,
        })
      : null;
    const directAgentExecution = directAgentToolContext?.execution || null;
    const directAgentToolTargetImageUrls = directAgentToolContext?.targetImageUrls || [];
    const directAgentToolTargetImageUrl = directAgentToolContext?.targetImageUrl || null;

    if (
      shouldRunAgentConversation &&
      !smartAutoNeedsClarification &&
      directAgentExecution?.toolName === "analyzeImage"
    ) {
      if (directAgentToolTargetImageUrls.length <= 0) {
        const missingTargetMessage = getDirectAgentToolTargetMissingMessage("analyze");
        const missingTargetStream = createUIMessageStream({
          execute: async ({ writer }) => {
            const messageId = generateUUID();
            writeCurrentAgentTargetLockChunk(writer, "agent:analyze:missing-target-lock");
            writeAssistantTextChunk(
              writer,
              missingTargetMessage,
              "agent:analyze:missing-target",
              messageId,
            );

            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId,
              text: missingTargetMessage,
            });
          },
        });

        return createSseResponse(missingTargetStream);
      }

      const analysisAssistantMessageId = generateUUID();
      const analysisSummaryAssetIds = Array.from(
        new Set([
          ...(requestTargetResolution?.targetAssetIds || []),
          ...(requestResolvedMediaInput.selectedAssetIds || []),
          ...(requestResolvedMediaInput.uploadedAssetIds || []),
          ...extractMessageImageAssetIds(message.parts as any[]),
        ]),
      );

      const directAnalyzeStream = createUIMessageStream({
        execute: async ({ writer }) => {
          writeAgentProgressChunk(
            writer,
            buildDirectAgentAnalyzePlanningProgress(),
            "agent:analyze:progress-planning",
          );
          writeCurrentAgentTargetLockChunk(writer, "agent:analyze:target-lock");

          try {
            const analysisResult = await executeDirectAgentImageAnalysis({
              requestTextContent,
              imageUrls: directAgentToolTargetImageUrls,
              context: effectiveAutoContextText || undefined,
              preferredModelId: preferredAgentModelId || finalModelId,
              answerModelId: finalModelId || preferredAgentModelId,
              assetIds: analysisSummaryAssetIds,
            });
            const assistantText = buildDirectAgentAnalysisAssistantText({
              summary: analysisResult.summary,
              answer: analysisResult.answer,
            });

            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId: analysisAssistantMessageId,
              text: assistantText,
            });

            await safePersistDirectAgentAnalyzeTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              currentSubIntent: smartAutoExecution?.routeSubIntent || "analyze",
              targetAssetIds: requestTargetResolution?.targetAssetIds || null,
              targetImageUrls: directAgentToolTargetImageUrls,
              messageId: analysisAssistantMessageId,
              requestTextContent,
            });

            writeAssistantTextChunk(
              writer,
              assistantText,
              "agent:analyze:success",
              analysisAssistantMessageId,
            );
            writeAgentProgressChunk(
              writer,
              buildDirectAgentAnalyzeCompletedProgress(),
              "agent:analyze:progress-completed",
            );
          } catch (directAnalyzeError) {
            chatApiLogger.error("[Chat API] Direct agent image analysis failed:", directAnalyzeError);
            const errorMessage = getDirectAgentToolErrorMessage("analyze", directAnalyzeError);

            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId: analysisAssistantMessageId,
              text: errorMessage,
            });

            writeAssistantTextChunk(
              writer,
              errorMessage,
              "agent:analyze:error",
              analysisAssistantMessageId,
            );
            writeAgentProgressChunk(
              writer,
              buildDirectAgentAnalyzeFailedProgress(errorMessage),
              "agent:analyze:progress-failed",
            );
          }
        },
      });

      return createSseResponse(directAnalyzeStream);
    }

    if (
      shouldRunAgentConversation &&
      !smartAutoNeedsClarification &&
      directAgentExecution?.toolName === "generateImage"
    ) {
      const directImageStream = createUIMessageStream({
        execute: async ({ writer }) => {
          writeAgentProgressChunk(
            writer,
            buildDirectAgentImageContextProgress({
              imageCount: directAgentToolTargetImageUrls.length,
              mode: "generate",
            }),
            "agent:generate_image:progress-image-context",
          );
          writeAgentProgressChunk(
            writer,
            buildDirectAgentImageGenerateSelectProgress(),
            "agent:generate_image:progress-select-tool",
          );
          writeCurrentAgentTargetLockChunk(writer, "agent:generate_image:target-lock");
          writeAssistantTextChunk(
            writer,
            "<!-- IMAGE_GENERATION_START -->",
            "agent:generate_image:start",
          );
          writeAgentProgressChunk(
            writer,
            buildDirectAgentImageGenerateExecutingProgress(),
            "agent:generate_image:progress-executing",
          );
          if (contextPayload?.source === "canvas") {
            writeImageGenerationStatusChunk(
              writer,
              {
                phase: "processing",
                providerType: requestedModelProviderType,
                modelName: finalModelId,
                imageCount:
                  effectiveImageParams?.imageCount ||
                  defaultImageQualityParams.imageCount ||
                  1,
              },
              "agent:generate_image:status-processing",
            );
          }

          const assistantMessageId = generateUUID();
          try {
            const directImageResult = await executeDirectAgentImageGeneration({
              requestTextContent,
              optimizedPrompt: smartAutoOptimizedPrompt,
              userId: session.user.id,
              finalModelId,
              imageParams: effectiveImageParams,
              defaultImageQualityParams,
              referenceImageUrls: directAgentToolTargetImageUrls,
            });
            const assistantText = buildDirectAgentImageGenerationAssistantText({
              imageMarkdown: directImageResult.imageMarkdown,
              modelDisplayName: directImageResult.model,
            });

            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId: assistantMessageId,
              text: assistantText,
            });

            await saveGeneratedImages(
              assistantText,
              session.user.id,
              id,
              assistantMessageId,
              directImageResult.prompt,
              directImageResult.modelRef || finalModelId,
              {
                sourceImageUrls: directAgentToolTargetImageUrls,
                relationType: "generated_from",
                sourceType:
                  directAgentToolTargetImageUrls.length > 0
                    ? "reference_generate"
                    : "generated",
                projectId: contextPayload?.projectId || null,
                userPrompt: requestTextContent,
                optimizedPrompt: directImageResult.prompt,
                requestedImageCount:
                  effectiveImageParams?.imageCount ||
                  defaultImageQualityParams.imageCount ||
                  1,
                aspectRatio:
                  effectiveImageParams?.aspectRatio ||
                  defaultImageQualityParams.aspectRatio,
                imageSize:
                  effectiveImageParams?.imageSize ||
                  defaultImageQualityParams.imageSize,
              },
            );

            writeAssistantTextChunk(
              writer,
              assistantText,
              "agent:generate_image:result",
              assistantMessageId,
            );
            if (contextPayload?.source === "canvas") {
              writeCanvasMediaChunk(
                writer,
                {
                  messageId: assistantMessageId,
                  imageUrls: directImageResult.images.map((image) => image.originalUrl),
                  prompt: directImageResult.prompt,
                  sourceImageUrls: directAgentToolTargetImageUrls,
                },
                "agent:generate_image:canvas-media",
              );
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "completed",
                  providerType: requestedModelProviderType,
                  modelName: directImageResult.model,
                  imageCount: directImageResult.imageCount,
                },
                "agent:generate_image:status-completed",
              );
            }
            writeAgentProgressChunk(
              writer,
              buildDirectAgentImageGenerateCompletedProgress(),
              "agent:generate_image:progress-completed",
            );
            writeAssistantTextChunk(
              writer,
              "<!-- IMAGE_GENERATION_END -->",
              "agent:generate_image:end",
            );
          } catch (directToolError) {
            chatApiLogger.error("[Chat API] Direct agent image generation failed:", directToolError);
            const errorMessage = getDirectAgentToolErrorMessage(
              "generate_image",
              directToolError,
            );
            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId: assistantMessageId,
              text: errorMessage,
            });
            writeAssistantTextChunk(
              writer,
              errorMessage,
              "agent:generate_image:error",
              assistantMessageId,
            );
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "failed",
                  providerType: requestedModelProviderType,
                  modelName: finalModelId,
                },
                "agent:generate_image:status-failed",
              );
            }
            writeAgentProgressChunk(
              writer,
              buildDirectAgentImageGenerateFailedProgress(errorMessage),
              "agent:generate_image:progress-failed",
            );
            writeAssistantTextChunk(
              writer,
              "<!-- IMAGE_GENERATION_END -->",
              "agent:generate_image:end-error",
            );
          }
        },
      });

      return createSseResponse(directImageStream);
    }

    if (
      shouldRunAgentConversation &&
      !smartAutoNeedsClarification &&
      directAgentExecution?.toolName === "generateVideo"
    ) {
      const directVideoStream = createUIMessageStream({
        execute: async ({ writer }) => {
          const assistantMessageId = generateUUID();
          writeAgentProgressChunk(
            writer,
            buildDirectAgentImageContextProgress({
              imageCount: directAgentToolTargetImageUrls.length,
              mode: "video",
            }),
            "agent:generate_video:progress-image-context",
          );
          writeAgentProgressChunk(
            writer,
            buildDirectAgentVideoGenerateSelectProgress(),
            "agent:generate_video:progress-select-tool",
          );
          writeCurrentAgentTargetLockChunk(writer, "agent:generate_video:target-lock");
          try {
            writeAgentProgressChunk(
              writer,
              buildDirectAgentVideoGenerateExecutingProgress(),
              "agent:generate_video:progress-executing",
            );
            const directVideoResult = await executeDirectAgentVideoGeneration({
              requestTextContent,
              optimizedPrompt: smartAutoOptimizedPrompt,
              finalModelId,
              sourceImageUrls: directAgentToolTargetImageUrls,
              videoParams: effectiveVideoParams,
              smartAutoExecution,
              smartAutoPlan,
            });
            const { mode, result, videoUrl } = directVideoResult;

            const assistantText = buildDirectAgentVideoGenerationAssistantText({
              videoUrl,
              modelDisplayName: result.modelDisplayName,
            });

            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId: assistantMessageId,
              text: assistantText,
              videoStorageStatus: "temporary",
              temporaryVideoUrl: videoUrl,
              videoMetadata: (result.metadata || {}) as any,
            });

            await safePersistDirectAgentVideoCompletedTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              messageId: assistantMessageId,
              requestTextContent,
              modelRef: result.modelRef || finalModelId,
              mode,
              temporaryVideoUrl: videoUrl,
            });

            await consumeGeneratedVideoPoints({
              userId: session.user.id,
              chatId: id,
              messageId: assistantMessageId,
              modelRefs: [result.modelRef || finalModelId],
              duration:
                Number((result.metadata as any)?.duration) ||
                Number(effectiveVideoParams?.duration) ||
                undefined,
              resolution:
                String(
                  (result.metadata as any)?.resolution ||
                    effectiveVideoParams?.resolution ||
                    ""
                ).trim() || undefined,
            });

            if (videoUrl) {
              scheduleVideoArchive({
                chatId: id,
                messageId: assistantMessageId,
                text: assistantText,
                temporaryVideoUrl: videoUrl,
                taskId: assistantMessageId,
                metadata: result.metadata,
              });
            }

            writeAssistantTextChunk(
              writer,
              assistantText,
              "agent:generate_video:result",
              assistantMessageId,
            );
            if (contextPayload?.source === "canvas") {
              writeCanvasMediaChunk(
                writer,
                {
                  messageId: assistantMessageId,
                  videoUrls: [videoUrl],
                  prompt: directVideoResult.prompt,
                  sourceImageUrls: directAgentToolTargetImageUrls,
                },
                "agent:generate_video:canvas-media",
              );
            }
            writeAgentProgressChunk(
              writer,
              buildDirectAgentVideoGenerateCompletedProgress(),
              "agent:generate_video:progress-completed",
            );
          } catch (directToolError) {
            chatApiLogger.error("[Chat API] Direct agent video generation failed:", directToolError);
            const errorMessage = getDirectAgentToolErrorMessage(
              "generate_video",
              directToolError,
            );
            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId: assistantMessageId,
              text: errorMessage,
            });
            await safePersistDirectAgentVideoFailedTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              messageId: assistantMessageId,
              requestTextContent,
              modelRef: finalModelId,
              error: directToolError,
            });
            writeAssistantTextChunk(
              writer,
              errorMessage,
              "agent:generate_video:error",
              assistantMessageId,
            );
            writeAgentProgressChunk(
              writer,
              buildDirectAgentVideoGenerateFailedProgress(errorMessage),
              "agent:generate_video:progress-failed",
            );
          }
        },
      });

      return createSseResponse(directVideoStream);
    }

    if (
      shouldRunAgentConversation &&
      !smartAutoNeedsClarification &&
      directAgentExecution &&
      isDirectAgentImageEditToolName(directAgentExecution.toolName)
    ) {
      const directAgentToolCapability = directAgentExecution.capability;
      if (!directAgentToolTargetImageUrl) {
        const missingTargetMessage = getDirectAgentToolTargetMissingMessage(
          directAgentToolCapability,
        );
        const missingTargetStream = createUIMessageStream({
          execute: async ({ writer }) => {
            const messageId = generateUUID();
            writeCurrentAgentTargetLockChunk(
              writer,
              `agent:${directAgentToolCapability}:missing-target-lock`,
            );
            writeAssistantTextChunk(
              writer,
              missingTargetMessage,
              `agent:${directAgentToolCapability}:missing-target`,
              messageId,
            );

            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId,
              text: missingTargetMessage,
            });
          },
        });

        return createSseResponse(missingTargetStream);
      }

      const assistantMessageId = generateUUID();
      const directToolLabel = getDirectAgentToolLabel(directAgentToolCapability);
      const directToolStream = createUIMessageStream({
        execute: async ({ writer }) => {
          writeAgentProgressChunk(
            writer,
            buildDirectAgentImageContextProgress({
              imageCount: directAgentToolTargetImageUrls.length,
              mode: "edit",
            }),
            `agent:${directAgentToolCapability}:progress-image-context`,
          );
          writeAgentProgressChunk(
            writer,
            buildDirectAgentImageEditSelectProgress({
              toolName: directAgentExecution.toolName,
              capability: directAgentToolCapability,
              label: directToolLabel,
            }),
            `agent:${directAgentToolCapability}:progress-select-tool`,
          );
          writeCurrentAgentTargetLockChunk(
            writer,
            `agent:${directAgentToolCapability}:target-lock`,
          );
          writeAgentProgressChunk(
            writer,
            buildDirectAgentImageEditExecutingProgress({
              toolName: directAgentExecution.toolName,
              capability: directAgentToolCapability,
              label: directToolLabel,
            }),
            `agent:${directAgentToolCapability}:progress-executing`,
          );

          try {
            const directImageEditResult = await executeDirectAgentImageEditTool({
              capability: directAgentToolCapability,
              requestUrl: request.url,
              requestHeaders: request.headers,
              userId: session.user.id,
              chatId: id,
              messageId: assistantMessageId,
              projectId: contextPayload?.projectId || null,
              targetAssetIds: requestTargetResolution?.targetAssetIds || null,
              sourceImageUrl: directAgentToolTargetImageUrl,
              sourceImageUrls: directAgentToolTargetImageUrls,
              requestTextContent,
              optimizedPrompt: smartAutoOptimizedPrompt,
              hiddenPromptPrefix,
              finalModelId,
              imageParams: effectiveImageParams,
              defaultImageQualityParams,
              smartAutoExecution,
              smartAutoPlan,
              saveGeneratedImages,
            });
            const resultOriginalUrl = directImageEditResult.originalUrl;
            const resultThumbnailUrl = directImageEditResult.thumbnailUrl;
            const resultImageSize = directImageEditResult.imageSize;
            const resultAssetId = directImageEditResult.mediaAssetId;

            const assistantText = buildDirectAgentImageEditAssistantText({
              capability: directAgentToolCapability,
              originalUrl: resultOriginalUrl,
              thumbnailUrl: resultThumbnailUrl,
              imageSize: resultImageSize,
            });

            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId: assistantMessageId,
              text: assistantText,
            });

            await safePersistDirectAgentImageEditTurn({
              userId: session.user.id,
              chatId: id,
              projectId: contextPayload?.projectId || null,
              capability: directAgentToolCapability,
              currentSubIntent: smartAutoExecution?.routeSubIntent || directAgentToolCapability,
              resultAssetId,
              resultOriginalUrl,
              resultImageSize,
              sourceImageUrls: directAgentToolTargetImageUrls,
              messageId: assistantMessageId,
              requestTextContent,
              optimizedPrompt: smartAutoOptimizedPrompt || undefined,
            });

            if (directAgentExecution.publishToCanvas && contextPayload?.source === "canvas") {
              chatApiLogger.info(`[Chat API] Agent publishToCanvas satisfied by assistant media auto-sync (${directAgentToolCapability})`);
            }

            writeAssistantTextChunk(
              writer,
              assistantText,
              `agent:${directAgentToolCapability}:success`,
              assistantMessageId,
            );
            if (contextPayload?.source === "canvas") {
              writeCanvasMediaChunk(
                writer,
                {
                  messageId: assistantMessageId,
                  imageUrls: resultOriginalUrl ? [resultOriginalUrl] : [],
                  prompt: requestTextContent || directToolLabel,
                  sourceImageUrls: directAgentToolTargetImageUrls,
                },
                `agent:${directAgentToolCapability}:canvas-media`,
              );
            }
            writeAgentProgressChunk(
              writer,
              buildDirectAgentImageEditCompletedProgress({
                toolName: directAgentExecution.toolName,
                capability: directAgentToolCapability,
                label: directToolLabel,
              }),
              `agent:${directAgentToolCapability}:progress-completed`,
            );
          } catch (directToolError) {
            chatApiLogger.error(`[Chat API] Direct agent tool ${directAgentToolCapability} failed:`, directToolError);

            if (!isDirectAgentImageEditServiceError(directToolError)) {
              chatApiLogger.warn(`[Chat API] Direct agent tool ${directAgentToolCapability} threw unexpected error type`);
            }

            const errorMessage = getDirectAgentToolErrorMessage(
              directAgentToolCapability,
              directToolError,
            );

            await saveAssistantTextOnlyMessage({
              chatId: id,
              messageId: assistantMessageId,
              text: errorMessage,
            });

            writeAssistantTextChunk(
              writer,
              errorMessage,
              `agent:${directAgentToolCapability}:error`,
              assistantMessageId,
            );
            writeAgentProgressChunk(
              writer,
              buildDirectAgentImageEditFailedProgress({
                toolName: directAgentExecution.toolName,
                capability: directAgentToolCapability,
                label: directToolLabel,
                errorMessage,
              }),
              `agent:${directAgentToolCapability}:progress-failed`,
            );
          }
        },
      });

      return createSseResponse(directToolStream);
    }

    let finalMergedUsage: AppUsage | undefined;

    // 获取启用的工具列表
    const enabledTools = await getEnabledTools();

    if (String(finalModelId || "").trim() === "auto") {
      const hasImageInputForAutoFallback =
        message.parts.some((part: any) =>
          part?.type === "file" || part?.type === "image" || part?.type === "image_url"
        ) || smartAutoHistoryImages.length > 0;
      const autoFallbackIntent =
        smartAutoExecution?.shouldApplyVideoPipeline || composerMode === "video"
          ? "video_gen"
          : smartAutoExecution?.shouldApplyImagePipeline ||
              composerMode === "image" ||
              composerMode === "detail"
            ? hasImageInputForAutoFallback
              ? "image_edit"
              : "image_gen"
            : hasImageInputForAutoFallback
              ? "vision"
              : "chat";

      try {
        const { routeToModel } = await import("@/lib/ai/model-router");
        const fallbackRoute = await routeToModel({
          intent: autoFallbackIntent,
          hasImage: hasImageInputForAutoFallback,
        });
        finalModelId = fallbackRoute.id;
        chatApiLogger.warn("[Chat API] Auto model was unresolved, routed to fallback model:", {
          intent: autoFallbackIntent,
          modelId: fallbackRoute.id,
          displayName: fallbackRoute.displayName,
          reason: fallbackRoute.reason,
        });
      } catch (autoModelRouteError) {
        chatApiLogger.error("[Chat API] Failed to route unresolved auto model:", autoModelRouteError);
        const enabledModels = await getEnabledAiModelsWithProvider(false);
        const nonAgentModels = enabledModels.filter(({ model }) => !isAiModelAgentAuto(model));
        const candidates = nonAgentModels.length > 0 ? nonAgentModels : enabledModels;
        const fallbackModel =
          candidates.find(({ model, provider }) => {
            if (!model.isEnabled || model.isSubModel) return false;
            const providerType = String(provider?.type || "");
            if (autoFallbackIntent === "video_gen") {
              return isVideoProviderType(providerType, model);
            }
            if (autoFallbackIntent === "image_edit" || autoFallbackIntent === "image_gen") {
              return isImageGenerationModelType(providerType, model);
            }
            return !isVideoProviderType(providerType, model) && !model.supportsImageGen;
          }) ||
          candidates.find(
            ({ model, provider }) =>
              model.isEnabled &&
              !model.isSubModel &&
              !isVideoProviderType(String(provider?.type || ""), model)
          ) ||
          candidates.find(({ model }) => model.isEnabled && !model.isSubModel);

        if (!fallbackModel) {
          return new ChatSDKError("bad_request:api", "No available models for auto mode").toResponse();
        }

        finalModelId = fallbackModel.model.id;
        chatApiLogger.warn("[Chat API] Auto model fallback used first available model:", {
          intent: autoFallbackIntent,
          modelId: fallbackModel.model.id,
          displayName: fallbackModel.model.displayName,
          providerType: fallbackModel.provider?.type,
        });
      }
    }

    // 检查是否是 UUID 格式（数据库中的模型 ID）
    const isUUID =
      /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(
        finalModelId
      );

    // 获取语言模型实例
    let languageModel;
    let actualModelId: string;
    let resolvedModelSupportsImageGen = false;
    let resolvedProviderType: string | undefined;
    let resolvedRuntimeModelLookupId = finalModelId;

    if (isUUID) {
      // 从数据库获取动态配置的模型
      let targetModelId = finalModelId;
      
      // 🆕 检查是否是视频主模型，如果是，根据 videoParams.mode 选择子模型
      const aiModelData = await getAiModelById({ id: finalModelId });
      const aiModelProvider = aiModelData
        ? await getAiProviderById({ id: aiModelData.providerId }).catch(() => null)
        : null;
      chatApiLogger.info("[Chat API] Model data:", { id: finalModelId, isSubModel: aiModelData?.isSubModel });
      
      if (aiModelData && !aiModelData.isSubModel && aiModelProvider?.type === "volcano-video") {
        // 检查是否有子模型
        const subModels = await getSubModelsByParentModelId(finalModelId);
        chatApiLogger.info("[Chat API] Found sub-models:", subModels.length);
        
        if (subModels.length > 0) {
          // 这是一个主模型，需要根据 videoParams 选择子模型
          const videoParams = effectiveVideoParams;
          chatApiLogger.info("[Chat API] Video params:", videoParams);
          
          // 如果没有 videoParams 或没有 mode，使用默认模式
          const mode = (videoParams?.mode || "text-to-video") as VideoModeType;
          chatApiLogger.info("[Chat API] Using mode:", mode);

          const matchedSubModel = selectBestVideoSubModelForMode(subModels as any, mode);

          if (matchedSubModel) {
            chatApiLogger.info(`[Chat API] 视频模式 ${mode} → 选择子模型: ${matchedSubModel.model.displayName} (${matchedSubModel.model.modelId})`);
            targetModelId = matchedSubModel.model.id;
          } else {
            chatApiLogger.warn(`[Chat API] 未找到可用子模型，继续使用主模型`);
          }
        }
      }
      
      const dynamicModel = await getLanguageModelById(targetModelId);
      if (!dynamicModel) {
        return new ChatSDKError(
          "bad_request:api",
          "Model not found or disabled"
        ).toResponse();
      }
      languageModel = dynamicModel;
      resolvedRuntimeModelLookupId = targetModelId;
      // 对于动态模型，我们需要从数据库获取 modelId
      const finalModelData = await getAiModelById({ id: targetModelId });
      actualModelId = finalModelData?.modelId ?? targetModelId;
      resolvedModelSupportsImageGen = Boolean(finalModelData?.supportsImageGen);
      if (finalModelData) {
        resolvedProviderType = (
          await getAiProviderById({ id: finalModelData.providerId }).catch(() => null)
        )?.type;
      }
    } else {
      // 使用预定义的模型
      languageModel = myProvider.languageModel(finalModelId);
      actualModelId = languageModel.modelId;
      resolvedProviderType = (languageModel as any)?.provider;
      resolvedRuntimeModelLookupId = actualModelId;
    }

    const effectiveConversationSystemPrompt = shouldRunAgentConversation
      ? `${await buildAgentRoleIdentityInstruction({
          allowVideoGeneration: allowAgentVideoGeneration,
          hasCanvasContext: Boolean(
            effectiveContextPayload?.source === "canvas" ||
              effectiveContextPayload?.selectedNodeIds?.length ||
              effectiveContextPayload?.canvasImageNodes?.length,
          ),
        })}\n\n${systemPrompt({ selectedChatModel: finalModelId, requestHints })}`
      : systemPrompt({ selectedChatModel: finalModelId, requestHints });

    const activeRuntimeModelDescriptor = await resolveAgentModelSlotDescriptor(
      resolvedRuntimeModelLookupId,
    ).catch(() => null);
    if (shouldRunAgentConversation && activeRuntimeModelDescriptor) {
      const slotName =
        smartAutoExecution?.shouldApplyImagePipeline ||
        smartAutoExecution?.shouldApplyVideoPipeline
          ? "execution"
          : "reply";
      agentModelSlots = upsertAgentModelSlot(agentModelSlots, slotName, {
        ...activeRuntimeModelDescriptor,
        source: "runtime_selected_model",
        reason:
          slotName === "reply"
            ? smartAutoExecution?.shouldStayConversational
              ? "conversational_reply_runtime"
              : "default_reply_runtime"
            : "execution_runtime_model",
        locked: slotName === "reply" ? shouldKeepSelectedModel : false,
      });
      pendingProtocolDebugEvents.push({
        phase: "modelSlots",
        payload: {
          modelSlots: agentModelSlots,
          providerHealth: activeRuntimeModelDescriptor.providerKey
            ? getProviderHealthSnapshot(activeRuntimeModelDescriptor.providerKey)
            : null,
        },
      });
    }

    // ========== 图片生成配额检查 ==========
    const isUuidModelId = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(
      finalModelId
    );
    const currentModelConfig = isUuidModelId
      ? await getAiModelById({ id: finalModelId }).catch(() => undefined)
      : undefined;
    const currentProviderConfig =
      currentModelConfig?.providerId
        ? await getAiProviderById({ id: currentModelConfig.providerId }).catch(() => null)
        : null;
    const runtimeProviderType = String(
      resolvedProviderType || (languageModel as any).provider || ""
    );
    const normalizedRuntimeProviderType =
      runtimeProviderType === "gemini-image"
        ? "gemini"
        : runtimeProviderType === "huanke-gemini"
          ? "huanke-gemini"
          : runtimeProviderType;
    const isImageGenerationModel = isImageGenerationModelType(
      normalizedRuntimeProviderType,
      currentModelConfig
        ? {
            modelId: currentModelConfig.modelId,
            capabilities: currentModelConfig.capabilities,
            supportsImageGen: currentModelConfig.supportsImageGen,
          }
        : undefined
    );
    const modelCreditCostPerImage = getModelCreditCost(currentModelConfig, "image", {
      imageSize:
        typeof effectiveImageParams?.imageSize === "string"
          ? effectiveImageParams.imageSize
          : defaultImageQualityParams.imageSize,
    });
    const modelCreditCostPerVideo = getModelCreditCost(currentModelConfig, "video", {
      duration: Number(effectiveVideoParams?.duration) || undefined,
      resolution: String(effectiveVideoParams?.resolution || "").trim() || undefined,
    });
    
    if (isImageGenerationModel) {
      const quota = await checkUserImageQuota(session.user.id);
      
      if (!quota.allowed) {
        chatApiLogger.info(`[Chat API] ⛔ 图片配额已用完: ${quota.used}/${quota.limit}`);
        return NextResponse.json(
          { 
            error: "quota_exceeded",
            message: `本月图片生成配额已用完（已使用 ${quota.used}/${quota.limit} 张），配额将于下月1日重置，如需更多配额请联系管理员。`,
            used: quota.used,
            limit: quota.limit,
          },
          { status: 429 }
        );
      }
      
      chatApiLogger.info(`[Chat API] ✅ 图片配额检查通过: ${quota.used}/${quota.limit ?? '无限制'}`);

      const pointsConfig = await getPointsSystemConfig();
      const normalizedUnitCost = Number.isFinite(modelCreditCostPerImage)
        ? Math.max(0, Math.round(modelCreditCostPerImage))
        : 0;

      if (pointsConfig.enabled && normalizedUnitCost > 0 && pointsConfig.blockOnInsufficient !== false) {
        const requestedImageCount = Math.max(
          1,
          Math.round(
            Number(
              effectiveImageParams?.imageCount || defaultImageQualityParams.imageCount || 1
            )
          )
        );
        const expectedCost = normalizedUnitCost * requestedImageCount;
        const userData = await getUserById({ id: session.user.id });
        if (!userData?.isHighVip) {
          const currentBalance = Math.max(0, Number(userData?.pointsBalance || 0));

          if (currentBalance < expectedCost) {
            return NextResponse.json(
              {
                error: "insufficient_points",
                message: `积分不足，当前余额 ${currentBalance}，本次预计消耗 ${expectedCost}（${normalizedUnitCost} x ${requestedImageCount} 张）。`,
                balance: currentBalance,
                expectedCost,
                unitCost: normalizedUnitCost,
              },
              { status: 402 }
            );
          }
        }
      }
    }

    const isVideoGenerationModel = isVideoProviderType(
      normalizedRuntimeProviderType,
      currentModelConfig
        ? {
            modelId: currentModelConfig.modelId,
            capabilities: currentModelConfig.capabilities,
            supportsImageGen: currentModelConfig.supportsImageGen,
          }
        : undefined
    );

    if (isVideoGenerationModel) {
      const pointsConfig = await getPointsSystemConfig();
      const normalizedVideoUnitCost = Number.isFinite(modelCreditCostPerVideo)
        ? Math.max(0, Math.round(modelCreditCostPerVideo))
        : 0;

      if (
        pointsConfig.enabled &&
        normalizedVideoUnitCost > 0 &&
        pointsConfig.blockOnInsufficient !== false
      ) {
        const requestedVideoDuration = Math.max(
          1,
          Math.round(Number(effectiveVideoParams?.duration || 0)) || 0
        );
        const expectedCost = normalizedVideoUnitCost;
        const userData = await getUserById({ id: session.user.id });
        if (!userData?.isHighVip) {
          const currentBalance = Math.max(0, Number(userData?.pointsBalance || 0));

          if (currentBalance < expectedCost) {
            return NextResponse.json(
              {
                error: "insufficient_points",
                message: requestedVideoDuration
                  ? `积分不足，当前余额 ${currentBalance}，本次预计消耗 ${expectedCost}（${requestedVideoDuration} 秒视频）。`
                  : `积分不足，当前余额 ${currentBalance}，本次预计消耗 ${expectedCost}（1 条视频）。`,
                balance: currentBalance,
                expectedCost,
                unitCost: normalizedVideoUnitCost,
                duration: requestedVideoDuration || undefined,
              },
              { status: 402 }
            );
          }
        }
      }
    }

    // ========== Gemini 图片生成独立处理 ==========
    // 支持 gemini-image 和 huanke-gemini 两种图片生成 provider
    const isGeminiImageProvider = ["gemini-image", "huanke-gemini"].includes((languageModel as any).provider);
    if (isGeminiImageProvider && typeof (languageModel as any).doGenerate === "function") {
      chatApiLogger.info("[Chat API] Using Gemini image generation, provider:", (languageModel as any).provider);
      chatApiLogger.info("[Chat API] Image params:", effectiveImageParams);
      
      // 🆕 获取备用模型配置
      const currentModelConfig = await getAiModelById({ id: finalModelId });
      const configuredFallbacks = [
        currentModelConfig?.fallbackModelId1,
        currentModelConfig?.fallbackModelId2,
      ].filter(Boolean) as string[];
      const allModels = await getEnabledAiModelsWithProvider();
      const currentModelEntry = resolveModelEntryByRuntimeModelId(
        allModels,
        actualModelId,
        finalModelId,
      );
      const fallbackCandidates = buildImageFallbackCandidates(allModels, {
        currentProviderId: currentModelConfig?.providerId,
        currentModelId: currentModelConfig?.id,
        currentModelKey: actualModelId,
        configuredFallbackIds: configuredFallbacks,
      });
      chatApiLogger.info("[Chat API] Gemini fallback candidates:", fallbackCandidates.map((candidate) => `${candidate.model.displayName}(${candidate.provider.type})`));
      
      const geminiStream = createUIMessageStream({
        execute: async ({ writer }) => {
          // 🆕 如果是智能模式且有对话回复，先发送对话消息让用户看到
          // 在消息末尾加上特殊标记，告诉前端"图片正在生成中"
          const conversationMessage = smartAutoFriendlyMessage || null;
          
          if (conversationMessage) {
            const chatMessageId = generateUUID();
            chatApiLogger.info("[Chat API] 💬 Gemini: Sending conversational reply first:", smartAutoFriendlyMessage);
            
            // 发送带标记的对话消息
            writeAssistantTextChunk(
              writer,
              conversationMessage,
              "gemini:conversation",
              chatMessageId,
            );
            
            // 保存对话消息到数据库（不带标记，纯对话）
            await saveMessages({
              messages: [
                {
                  id: chatMessageId,
                  chatId: id,
                  role: "assistant",
                  parts: [{ type: "text", text: smartAutoFriendlyMessage }],
                  attachments: [],
                  createdAt: new Date(),
                  videoStorageStatus: null,
                  temporaryVideoUrl: null,
                  permanentVideoUrl: null,
                  archivedAt: null,
                  videoMetadata: null,
                },
              ],
            });
          }
          
          const buildMessagesForGemini = () => {
            const lastUserMessage = uiMessagesForModel.filter((m) => m.role === "user").pop();
            let messagesForGemini = lastUserMessage ? [lastUserMessage] : uiMessagesForModel;
            messagesForGemini = applyOptimizedPromptToLatestUserMessage(
              messagesForGemini,
              smartAutoOptimizedPrompt,
              hiddenPromptPrefix,
            );
            return injectHistoryImagesToLastUserMessage(messagesForGemini, smartAutoHistoryImages);
          };

          // 🆕 尝试生成图片的函数（支持备用模型切换）
          const tryGenerateImage = async (modelIdToUse: string, isRetry = false): Promise<string> => {
            chatApiLogger.info(`[Chat API] ${isRetry ? "🔄 Retry with fallback" : "🚀 Trying"} model: ${modelIdToUse}`);
            
            // 只传递最后一条用户消息，避免上下文历史干扰生图效果
            const messagesForGemini = buildMessagesForGemini();
            chatApiLogger.info("[Chat API] Gemini: Using only last user message (no history context)");
            
            // 转换消息：gemini-image 需要 base64 格式，huanke-gemini 需要 URL 格式
            const providerForConvert = (languageModel as any).provider === "huanke-gemini" ? "huanke-gemini" : "gemini";
            const modelMessages = await convertMessagesWithImages(messagesForGemini, providerForConvert);
            chatApiLogger.info("[Chat API] Message conversion provider:", providerForConvert);
            
            // 调用 doGenerate 获取图片（如果是备用模型，传入 overrideModelId）
            const result = await (languageModel as any).doGenerate({
              messages: modelMessages,
              imageParams:
                effectiveImageParams || {
                  aspectRatio: defaultImageQualityParams.aspectRatio,
                  imageSize: defaultImageQualityParams.imageSize,
                },
              overrideModelId: isRetry ? modelIdToUse : undefined, // 🆕 使用备用模型 ID
            });
            
            return result.text || "图片生成失败";
          };
          
          let stopKeepalive: (() => void) | null = null;
          try {
            let imageMarkdown = ""; // 初始化为空字符串
            let usedModelId = actualModelId;
            const generationStartedAt = Date.now();

	            // 🆕 图片生成真正开始时发出标记（用于前端显示占位图）
	            writeAssistantTextChunk(
	              writer,
	              "<!-- IMAGE_GENERATION_START -->",
	              "gemini:image-start",
	            );
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "processing",
                  providerType: (languageModel as any).provider,
                  modelName: currentModelConfig?.displayName || actualModelId,
                  imageCount: effectiveImageParams?.imageCount || defaultImageQualityParams.imageCount || 1,
                },
                "gemini:image-status-start",
              );
            }
	            stopKeepalive = startStreamKeepalive(writer, "gemini-image");
            
            try {
              // 首先尝试主模型
              imageMarkdown = await tryGenerateImage(actualModelId, false);
            } catch (primaryError) {
              chatApiLogger.error("[Chat API] Primary model failed:", primaryError);
              await recordAiModelHealthFailure({
                model: currentModelEntry?.model || currentModelConfig,
                provider: currentModelEntry?.provider,
                error: primaryError,
                context: "chat_gemini_primary",
                elapsedMs: Date.now() - generationStartedAt,
                metadata: {
                  runtimeModelId: actualModelId,
                  finalModelId,
                  providerType: (languageModel as any).provider,
                  aspectRatio: effectiveImageParams?.aspectRatio,
                  imageSize: effectiveImageParams?.imageSize,
                  imageCount:
                    effectiveImageParams?.imageCount ||
                    defaultImageQualityParams.imageCount ||
                    1,
                },
              }).catch((healthError) => {
                chatApiLogger.warn("[Chat API] Record Gemini primary health failure failed:", healthError);
              });
              
              // 🆕 尝试备用模型（支持跨服务商切换）
              let fallbackSuccess = false;
              const triedFallbackModelIds = new Set<string>();
              for (const candidate of fallbackCandidates) {
                try {
                  triedFallbackModelIds.add(String(candidate.model.id || ""));
                  chatApiLogger.info(`[Chat API] 🔄 Trying fallback model: ${candidate.model.displayName} (${candidate.provider.type})`);
                  const fallbackResult = await generateImageWithFailoverCandidate({
                    candidate,
                    messages: buildMessagesForGemini(),
                    imageParams: effectiveImageParams,
                    fallbackImageParams: {
                      aspectRatio: defaultImageQualityParams.aspectRatio,
                      imageSize: defaultImageQualityParams.imageSize,
                    },
                  });
                  imageMarkdown = fallbackResult.text;
                  usedModelId = fallbackResult.usedModelId;
                  fallbackSuccess = true;
                  chatApiLogger.info(`[Chat API] ✅ Fallback model ${fallbackResult.displayName} succeeded!`);
                  break;
                } catch (fallbackError) {
                  const fallbackErrorMessage = normalizeFailoverErrorMessage(fallbackError);
                  if (shouldCooldownImageFallbackModel(fallbackErrorMessage)) {
                    setImageFallbackModelCooldown(candidate.model.id, fallbackErrorMessage);
                  }
                  await recordAiModelHealthFailure({
                    model: candidate.model,
                    provider: candidate.provider,
                    error: fallbackError,
                    context: "chat_gemini_fallback",
                    elapsedMs: Date.now() - generationStartedAt,
                    metadata: {
                      primaryModelId: actualModelId,
                      fallbackModelId: candidate.model.modelId,
                      providerType: candidate.provider.type,
                      aspectRatio: effectiveImageParams?.aspectRatio,
                      imageSize: effectiveImageParams?.imageSize,
                    },
                  }).catch((healthError) => {
                    chatApiLogger.warn("[Chat API] Record Gemini fallback health failure failed:", healthError);
                  });
                  chatApiLogger.error(`[Chat API] ❌ Fallback model ${candidate.model.displayName} (${candidate.provider.type}) failed:`, fallbackError);
                }
              }

              if (!fallbackSuccess) {
                const providerPriority: Record<string, number> = {
                  "volcano-vision": 0,
                  "alibaba-image": 1,
                  "bfl-image": 2,
                  "ruxa-image": 3,
                  "fal-image": 4,
                  "openai-image": 5,
                  "stepfun-image": 6,
                  "grsai-gpt-image": 7,
                  runway: 8,
                  krea: 9,
                  gemini: 9,
                  "huanke-gemini": 10,
                };
                const crossProviderCandidates = getImageCrossProviderCandidates(allModels, {
                  currentModelId: finalModelId,
                  currentProviderId: currentModelConfig?.providerId,
                  providerPriority,
                }).filter((candidate) => !triedFallbackModelIds.has(String(candidate.model.id || "")));

                for (const candidate of crossProviderCandidates) {
                  try {
                    triedFallbackModelIds.add(String(candidate.model.id || ""));
                    chatApiLogger.info(`[Chat API] 🔁 Gemini cross-provider failover: ${candidate.model.displayName} (${candidate.provider.type})`);
                    const fallbackResult = await generateImageWithFailoverCandidate({
                      candidate,
                      messages: buildMessagesForGemini(),
                      imageParams: effectiveImageParams,
                      fallbackImageParams: {
                        aspectRatio: defaultImageQualityParams.aspectRatio,
                        imageSize: defaultImageQualityParams.imageSize,
                        imageCount: defaultImageQualityParams.imageCount,
                      },
                    });
                    imageMarkdown = fallbackResult.text;
                    usedModelId = fallbackResult.usedModelId;
                    fallbackSuccess = true;
                    chatApiLogger.info(`[Chat API] ✅ Gemini cross-provider fallback model ${fallbackResult.displayName} succeeded!`);
                    break;
                  } catch (fallbackError) {
                    const fallbackErrorMessage = normalizeFailoverErrorMessage(fallbackError);
                    if (shouldCooldownImageFallbackModel(fallbackErrorMessage)) {
                      setImageFallbackModelCooldown(candidate.model.id, fallbackErrorMessage);
                    }
                    await recordAiModelHealthFailure({
                      model: candidate.model,
                      provider: candidate.provider,
                      error: fallbackError,
                      context: "chat_gemini_cross_fallback",
                      elapsedMs: Date.now() - generationStartedAt,
                      metadata: {
                        primaryModelId: actualModelId,
                        fallbackModelId: candidate.model.modelId,
                        providerType: candidate.provider.type,
                        aspectRatio: effectiveImageParams?.aspectRatio,
                        imageSize: effectiveImageParams?.imageSize,
                      },
                    }).catch((healthError) => {
                      chatApiLogger.warn("[Chat API] Record Gemini cross-provider health failure failed:", healthError);
                    });
                    chatApiLogger.error(`[Chat API] ❌ Gemini cross-provider fallback model ${candidate.model.displayName} (${candidate.provider.type}) failed:`, fallbackError);
                  }
                }
              }
              
              // 如果所有备用模型都失败，抛出原始错误触发火山引擎故障转移
              if (!fallbackSuccess) {
                throw primaryError;
              }
            }
            
            chatApiLogger.info("[Chat API] Gemini generated, length:", imageMarkdown.length);
            chatApiLogger.info("[Chat API] Gemini image markdown:", imageMarkdown.substring(0, 200));
            chatApiLogger.info("[Chat API] Used model ID:", usedModelId);

            const usedModelEntry = resolveModelEntryByRuntimeModelId(
              allModels,
              usedModelId,
              usedModelId === actualModelId ? finalModelId : undefined,
            );
            await recordAiModelHealthSuccess({
              model: usedModelEntry?.model || (usedModelId === actualModelId ? currentModelConfig : null),
            }).catch((healthError) => {
              chatApiLogger.warn("[Chat API] Record Gemini health success failed:", healthError);
            });

            const usedModelDisplayName =
              resolveModelDisplayNameByModelId(allModels, usedModelId) ||
              currentModelConfig?.displayName ||
              actualModelId;
            const imageMarkdownWithModel = prependImageModelBadge(
              imageMarkdown,
              usedModelDisplayName,
            );
            
            // 生成一个统一的消息 ID
            const messageId = generateUUID();
            
            // 写入消息到流 - 使用正确的 parts 格式
	            writeAssistantTextChunk(
	              writer,
	              imageMarkdownWithModel,
	              "gemini:image-result",
	              messageId,
	            );
            if (contextPayload?.source === "canvas") {
              writeCanvasMediaChunk(
                writer,
                {
                  messageId,
                  text: imageMarkdownWithModel,
                  prompt: requestTextContent,
                  sourceImageUrls: requestTargetResolution?.targetImageUrls || [],
                },
                "gemini:image-canvas-media",
              );
            }
	            
	            // 🆕 图片生成结束标记（成功）
	            writeAssistantTextChunk(
	              writer,
	              "<!-- IMAGE_GENERATION_END -->",
	              "gemini:image-end-success",
	            );
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "completed",
                  providerType: (languageModel as any).provider,
                  modelName: usedModelDisplayName,
                  imageCount: effectiveImageParams?.imageCount || defaultImageQualityParams.imageCount || 1,
                },
                "gemini:image-status-completed",
              );
            }
            
            // 保存消息到数据库（现在是 S3 URL，可以完整保存）
            try {
              await saveMessages({
                messages: [
                  {
                    id: messageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: imageMarkdownWithModel }],
                    attachments: [], // 必须提供 attachments 字段（数据库 notNull）
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
              chatApiLogger.info("[Chat API] ✅ Gemini message saved successfully!");
              
              // 提取用户 prompt（最后一条用户消息的文本）
              const lastUserMessage = uiMessages.filter((m) => m.role === "user").pop();
              const userPrompt = lastUserMessage?.parts?.find((p): p is { type: "text"; text: string } => p.type === "text")?.text || "";
              
              // 保存图片记录到 GeneratedImage 表
              await saveGeneratedImages(
                imageMarkdownWithModel,
                session.user.id,
                id,
                messageId,
                userPrompt,
                resolveModelRefByRuntimeModelId(
                  allModels,
                  usedModelId,
                  usedModelId === actualModelId ? finalModelId : undefined,
                ),
                {
                  sourceAssetIds: requestTargetResolution?.targetAssetIds,
                  sourceImageUrls: requestTargetResolution?.targetImageUrls,
                  relationType: requestResolvedMediaInput?.hasImage ? "edited_from" : "generated_from",
                  sourceType: requestResolvedMediaInput?.hasImage ? "generated" : "generated",
                  projectId: contextPayload?.projectId || null,
                  optimizedPrompt: smartAutoOptimizedPrompt || userPrompt,
                  requestedImageCount: effectiveImageParams?.imageCount,
                  aspectRatio: effectiveImageParams?.aspectRatio,
                  imageSize: effectiveImageParams?.imageSize,
                },
              );
            } catch (saveError) {
              chatApiLogger.error("[Chat API] ❌ Failed to save Gemini message to database:", saveError);
              chatApiLogger.error("[Chat API] Message content that failed:", imageMarkdown.substring(0, 300));
            }
          } catch (error) {
            chatApiLogger.error("[Chat API] Gemini generation error:", error);
            chatApiLogger.info("[Chat API] Attempting failover to Volcano Vision...");
            
            // 故障转移：尝试使用火山引擎模型
            try {
              // 查找火山引擎模型
              const allModels = await getEnabledAiModelsWithProvider();
              chatApiLogger.info("[Chat API] Total enabled models:", allModels.length);
              
              const volcanoModel = allModels.find(
                (m: any) => m.provider.type === "volcano-vision" && m.model.isEnabled
              );
              
              if (volcanoModel) {
                chatApiLogger.info("[Chat API] Found Volcano Vision model for failover:", volcanoModel.model.id);
                
                // 获取火山引擎模型实例
                const volcanoLanguageModel = await getLanguageModelById(volcanoModel.model.id);
                
                if (volcanoLanguageModel && typeof (volcanoLanguageModel as any).doGenerate === "function") {
                  chatApiLogger.info("[Chat API] Executing Volcano Vision failover...");
                  
                  // 转换消息（火山引擎会自动处理 Base64）
                  const volcanoMessages = await convertMessagesWithImages(
                    injectHistoryImagesToLastUserMessage(uiMessagesForModel, smartAutoHistoryImages),
                    "volcano"
                  );
                  
                  // 调用火山引擎生成（故障转移时只生成 1 张，保持与 Gemini 一致）
                  const volcanoResult = await (volcanoLanguageModel as any).doGenerate({
                    messages: volcanoMessages,
                    maxImages: 1,  // 故障转移时只生成 1 张
                    imageParams:
                      effectiveImageParams || {
                        aspectRatio: defaultImageQualityParams.aspectRatio,
                        imageSize: defaultImageQualityParams.imageSize,
                        imageCount: defaultImageQualityParams.imageCount,
                      },
                  });
                  
                  const imageMarkdown = volcanoResult.text || "图片生成失败";
                  const imageMarkdownWithModel = prependImageModelBadge(
                    imageMarkdown,
                    volcanoModel.model.displayName || volcanoModel.model.modelId,
                  );
                  chatApiLogger.info("[Chat API] Volcano Vision failover success, length:", imageMarkdown.length);
                  
                  // 生成消息 ID
                  const messageId = generateUUID();
                  
                  // 写入消息到流
	                  writeAssistantTextChunk(
	                    writer,
	                    imageMarkdownWithModel,
	                    "gemini:volcano-failover-result",
	                    messageId,
	                  );
                    if (contextPayload?.source === "canvas") {
                      writeCanvasMediaChunk(
                        writer,
                        {
                          messageId,
                          text: imageMarkdownWithModel,
                          prompt: requestTextContent,
                          sourceImageUrls: requestTargetResolution?.targetImageUrls || [],
                        },
                        "gemini:volcano-failover-canvas-media",
                      );
                    }
	                  
	                  // 🆕 图片生成结束标记（故障转移成功）
	                  writeAssistantTextChunk(
	                    writer,
	                    "<!-- IMAGE_GENERATION_END -->",
	                    "gemini:volcano-failover-end",
	                  );
                    if (contextPayload?.source === "canvas") {
                      writeImageGenerationStatusChunk(
                        writer,
                        {
                          phase: "completed",
                          providerType: "volcano-vision",
                          modelName: volcanoModel.model.displayName || volcanoModel.model.modelId,
                          imageCount: 1,
                        },
                        "gemini:volcano-failover-status-completed",
                      );
                    }
                  
                  // 保存消息到数据库
                  try {
                    await saveMessages({
                      messages: [
                        {
                          id: messageId,
                          chatId: id,
                          role: "assistant",
                          parts: [{ type: "text", text: imageMarkdownWithModel }],
                          attachments: [],
                          createdAt: new Date(),
                          videoStorageStatus: null,
                          temporaryVideoUrl: null,
                          permanentVideoUrl: null,
                          archivedAt: null,
                          videoMetadata: null,
                        },
                      ],
                    });
                    chatApiLogger.info("[Chat API] ✅ Volcano Vision failover message saved!");
                    
                    // 提取用户 prompt
                    const lastUserMessage = uiMessages.filter((m) => m.role === "user").pop();
                    const userPrompt = lastUserMessage?.parts?.find((p): p is { type: "text"; text: string } => p.type === "text")?.text || "";
                    
                    // 保存图片记录到 GeneratedImage 表
                    await saveGeneratedImages(
                      imageMarkdownWithModel,
                      session.user.id,
                      id,
                      messageId,
                      userPrompt,
                      volcanoModel.model.id,
                      {
                        sourceAssetIds: requestTargetResolution?.targetAssetIds,
                        sourceImageUrls: requestTargetResolution?.targetImageUrls,
                        relationType: requestResolvedMediaInput?.hasImage ? "edited_from" : "generated_from",
                        sourceType: "generated",
                        projectId: contextPayload?.projectId || null,
                        optimizedPrompt: smartAutoOptimizedPrompt || userPrompt,
                        requestedImageCount: effectiveImageParams?.imageCount,
                        aspectRatio: effectiveImageParams?.aspectRatio,
                        imageSize: effectiveImageParams?.imageSize,
                      },
                    );
                  } catch (saveError) {
                    chatApiLogger.error("[Chat API] Failed to save failover message:", saveError);
                  }
                  
                  return; // 成功，直接返回
                }
              }
              
              chatApiLogger.info("[Chat API] No Volcano Vision model available for failover");
            } catch (failoverError) {
              chatApiLogger.error("[Chat API] Failover to Volcano Vision also failed:", failoverError);
            }
            
            // 如果故障转移也失败，返回错误消息
            const errorMessageId = generateUUID();
            writeAssistantTextChunk(
              writer,
              "图片生成失败，请稍后重试",
              "gemini:error",
              errorMessageId,
            );
            
            // 🆕 图片生成结束标记（失败）
            writeAssistantTextChunk(
              writer,
              "<!-- IMAGE_GENERATION_END -->",
              "gemini:image-end-failed",
            );
            
            // 尝试保存错误消息
            try {
              await saveMessages({
                messages: [
                  {
                    id: errorMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: "图片生成失败，请稍后重试" }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
            } catch (saveError) {
              chatApiLogger.error("[Chat API] Failed to save error message:", saveError);
            }
          } finally {
            stopKeepalive?.();
          }
        },
      });
      
      return createSseResponse(geminiStream);
    }
    // ========== Gemini 处理结束 ==========

    // ========== 阿里云千问图片生成独立处理 ==========
    const isAlibabaLikeImageProvider =
      isImageGenerationModel &&
      [
        "alibaba-image",
        "bfl-image",
        "ruxa-image",
        "fal-image",
        "openai-image",
        "stepfun-image",
        "midjourney",
        "runway",
        "krea",
      ].includes((languageModel as any).provider);
    if (isAlibabaLikeImageProvider && typeof (languageModel as any).doGenerate === "function") {
      chatApiLogger.info("[Chat API] Using image generation provider:", (languageModel as any).provider);
      chatApiLogger.info("[Chat API] Image params:", effectiveImageParams);
      
      // 🆕 获取模型显示名称，用于错误提示
      const alibabaModelConfig = await getAiModelById({ id: finalModelId });
      const modelDisplayName = alibabaModelConfig?.displayName || actualModelId;
      const configuredFallbacks = [
        alibabaModelConfig?.fallbackModelId1,
        alibabaModelConfig?.fallbackModelId2,
      ].filter(Boolean) as string[];
      const allModels = await getEnabledAiModelsWithProvider();
      const fallbackCandidates = buildImageFallbackCandidates(allModels, {
        currentProviderId: alibabaModelConfig?.providerId,
        currentModelId: alibabaModelConfig?.id,
        currentModelKey: actualModelId,
        configuredFallbackIds: configuredFallbacks,
      });
      chatApiLogger.info("[Chat API] Alibaba fallback candidates:", fallbackCandidates.map((candidate) => `${candidate.model.displayName}(${candidate.provider.type})`));
      
      const alibabaStream = createUIMessageStream({
        execute: async ({ writer }) => {
          let stopKeepalive: (() => void) | null = null;
          try {
            // 🆕 如果是智能模式且有对话回复，先发送对话消息让用户看到
            const conversationMessage = smartAutoFriendlyMessage || null;
            
            if (conversationMessage) {
              const chatMessageId = generateUUID();
              chatApiLogger.info("[Chat API] 💬 Sending conversational reply first:", smartAutoFriendlyMessage);
              
              // 发送带标记的对话消息
              writeAssistantTextChunk(
                writer,
                conversationMessage,
                "alibaba:conversation",
                chatMessageId,
              );
              
              // 保存对话消息到数据库（不带标记，纯对话）
              await saveMessages({
                messages: [
                  {
                    id: chatMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: smartAutoFriendlyMessage }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
            }
            
            // 只传递最后一条用户消息
            const lastUserMessage = uiMessagesForModel.filter((m) => m.role === "user").pop();
            let messagesForAlibaba = lastUserMessage ? [lastUserMessage] : uiMessagesForModel;
            chatApiLogger.info("[Chat API] Alibaba: Using only last user message");
            
            // 🆕 如果有智能模式优化后的提示词，替换消息中的文本（仅用于API调用）
            if (smartAutoOptimizedPrompt) {
              chatApiLogger.info("[Chat API] Using optimized prompt for API call");
              messagesForAlibaba = applyOptimizedPromptToLatestUserMessage(
                messagesForAlibaba,
                smartAutoOptimizedPrompt,
                hiddenPromptPrefix,
              );
            }

            const resolvedTargetImageUrlsForProvider = normalizeResolvedTargetImageUrls(
              requestTargetResolution?.targetImageUrls
            );
            if (resolvedTargetImageUrlsForProvider.length > 0) {
              messagesForAlibaba = applyResolvedTargetImagesToLastUserMessage(
                messagesForAlibaba,
                resolvedTargetImageUrlsForProvider
              );
              chatApiLogger.info("[Chat API] Image provider target images:", {
                resolutionMode: requestTargetResolution?.resolutionMode || null,
                imageCount: resolvedTargetImageUrlsForProvider.length,
                firstImageUrl: summarizeTargetImageUrl(resolvedTargetImageUrlsForProvider[0]),
              });
            }
            
            messagesForAlibaba = injectHistoryImagesToLastUserMessage(messagesForAlibaba, smartAutoHistoryImages);
            const isFalAsyncImageEdit =
              (languageModel as any).provider === "fal-image" &&
              isFalGptImage2EditModelId(actualModelId);

            if (isFalAsyncImageEdit) {
              const falProvider = alibabaModelConfig?.providerId
                ? await getAiProviderById({ id: alibabaModelConfig.providerId }).catch(() => undefined)
                : undefined;
              const falApiKey = String(falProvider?.apiKey || "").trim();
              if (!falApiKey) {
                throw new Error("FAL 图片编辑模型未配置可用的 API Key");
              }

              const falMessages = await convertMessagesWithImages(messagesForAlibaba, "fal-image");
              const queuedTask = await submitFalImageTask({
                apiKey: falApiKey,
                modelId: actualModelId,
                messages: falMessages,
                imageParams:
                  effectiveImageParams || {
                    aspectRatio: defaultImageQualityParams.aspectRatio,
                    imageSize: defaultImageQualityParams.imageSize,
                    imageCount: defaultImageQualityParams.imageCount,
                  },
              });

              const placeholderMessageId = generateUUID();
              const userPrompt =
                lastUserMessage?.parts?.find(
                  (p): p is { type: "text"; text: string } => p.type === "text",
                )?.text || "";
              const modelRef = resolveModelRefByRuntimeModelId(
                allModels,
                queuedTask.modelId,
                finalModelId,
              );
              const placeholderText = `已提交 ${modelDisplayName} 编辑任务，预计 2-4 分钟完成，结果会自动回填到这里。`;
              const queuedMetadata: FalImageEditTaskMetadata = {
                taskKind: "fal_gpt_image_2_edit",
                provider: "fal-image",
                providerId: String(alibabaModelConfig?.providerId || ""),
                endpointId: queuedTask.endpointId,
                requestId: queuedTask.requestId,
                modelId: queuedTask.modelId,
                modelRef,
                modelDisplayName,
                prompt: queuedTask.prompt,
                optimizedPrompt: smartAutoOptimizedPrompt || userPrompt || queuedTask.prompt,
                userPrompt: userPrompt || queuedTask.prompt,
                requestedImageCount:
                  effectiveImageParams?.imageCount || defaultImageQualityParams.imageCount || 1,
                aspectRatio: effectiveImageParams?.aspectRatio,
                imageSize: effectiveImageParams?.imageSize,
                outputSizeLabel: queuedTask.outputSizeLabel,
                sourceImageUrls: requestTargetResolution?.targetImageUrls || queuedTask.sourceImageUrls,
                sourceAssetIds: requestTargetResolution?.targetAssetIds || [],
                relationType: requestResolvedMediaInput?.hasImage ? "edited_from" : "generated_from",
                sourceType: "generated",
                projectId: contextPayload?.projectId || null,
                contextSource: contextPayload?.source || null,
                status: "queued",
                startedAt: Date.now(),
                updatedAt: Date.now(),
                queuePosition: null,
                lastLogs: [],
                error: null,
              };

              writeAssistantTextChunk(
                writer,
                "<!-- IMAGE_GENERATION_START -->",
                "alibaba:image-start",
              );
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "queued",
                  providerType: "fal-image",
                  modelName: modelDisplayName,
                  imageCount:
                    effectiveImageParams?.imageCount || defaultImageQualityParams.imageCount || 1,
                },
                "alibaba:image-status-queued",
              );
              writeAssistantTextChunk(
                writer,
                placeholderText,
                "alibaba:image-queued",
                placeholderMessageId,
              );

              await saveMessages({
                messages: [
                  {
                    id: placeholderMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: placeholderText }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: queuedMetadata as any,
                  },
                ],
              });

              chatApiLogger.info("[Chat API] ✅ Queued FAL GPT Image 2 Edit task", {
                requestId: queuedTask.requestId,
                endpointId: queuedTask.endpointId,
                messageId: placeholderMessageId,
              });
              return;
            }
            
            const tryGenerateImage = async (modelIdToUse: string, isRetry: boolean) => {
              // 转换消息（图片编辑模型统一使用 URL 输入）
              const providerForConvert =
                (languageModel as any).provider === "bfl-image"
                  ? "bfl-image"
                  : (languageModel as any).provider === "ruxa-image"
                  ? "ruxa-image"
                  : (languageModel as any).provider === "fal-image"
                    ? "fal-image"
                    : (languageModel as any).provider === "openai-image"
                      ? "openai-image"
                    : (languageModel as any).provider === "stepfun-image"
                      ? "stepfun-image"
                      : (languageModel as any).provider === "midjourney"
                        ? "midjourney"
                      : (languageModel as any).provider === "runway"
                        ? "runway"
                      : (languageModel as any).provider === "krea"
                        ? "krea"
                    : "alibaba-image";
              const modelMessages = await convertMessagesWithImages(messagesForAlibaba, providerForConvert);
              
              // 调用 doGenerate 获取图片，传递模型显示名称
              const result = await (languageModel as any).doGenerate({
                messages: modelMessages,
                imageParams:
                  effectiveImageParams || {
                    aspectRatio: defaultImageQualityParams.aspectRatio,
                    imageSize: defaultImageQualityParams.imageSize,
                    imageCount: defaultImageQualityParams.imageCount,
                  },
                modelDisplayName, // 🆕 传递模型显示名称
                overrideModelId: isRetry ? modelIdToUse : undefined,
              });
              
              if (result?.finishReason === "error") {
                throw new Error(result.text || "图片生成失败");
              }
              
              return result.text || "图片生成失败";
            };
            
            let imageMarkdown = "";
            let usedModelId = actualModelId;

            // 🆕 图片生成真正开始时发出标记（用于前端显示占位图）
	            writeAssistantTextChunk(
	              writer,
	              "<!-- IMAGE_GENERATION_START -->",
	              "alibaba:image-start",
	            );
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "processing",
                  providerType: (languageModel as any).provider,
                  modelName: alibabaModelConfig?.displayName || actualModelId,
                  imageCount: effectiveImageParams?.imageCount || defaultImageQualityParams.imageCount || 1,
                },
                "alibaba:image-status-start",
              );
            }
	            stopKeepalive = startStreamKeepalive(writer, "alibaba-image");
            
            try {
              imageMarkdown = await tryGenerateImage(actualModelId, false);
	            } catch (primaryError) {
	              chatApiLogger.error("[Chat API] Alibaba primary model failed:", primaryError);
	              
	              let fallbackSuccess = false;
              for (const candidate of fallbackCandidates) {
                try {
                  chatApiLogger.info(`[Chat API] 🔄 Alibaba fallback model: ${candidate.model.displayName} (${candidate.provider.type})`);
                  const fallbackResult = await generateImageWithFailoverCandidate({
                    candidate,
                    messages: messagesForAlibaba,
                    imageParams: effectiveImageParams,
                    fallbackImageParams: {
                      aspectRatio: defaultImageQualityParams.aspectRatio,
                      imageSize: defaultImageQualityParams.imageSize,
                      imageCount: defaultImageQualityParams.imageCount,
                    },
                  });
                  imageMarkdown = fallbackResult.text;
                  usedModelId = fallbackResult.usedModelId;
                  fallbackSuccess = true;
                  chatApiLogger.info(`[Chat API] ✅ Alibaba fallback model ${fallbackResult.displayName} succeeded!`);
                  break;
                } catch (fallbackError) {
                  const fallbackErrorMessage = normalizeFailoverErrorMessage(fallbackError);
                  if (shouldCooldownImageFallbackModel(fallbackErrorMessage)) {
                    setImageFallbackModelCooldown(candidate.model.id, fallbackErrorMessage);
                  }
                  chatApiLogger.error(`[Chat API] ❌ Alibaba fallback model ${candidate.model.displayName} (${candidate.provider.type}) failed:`, fallbackError);
                }
              }

              if (!fallbackSuccess) {
                const providerPriority: Record<string, number> = {
                  "volcano-vision": 0,
                  "alibaba-image": 1,
                  "bfl-image": 2,
                  "ruxa-image": 3,
                  "fal-image": 4,
                  "openai-image": 5,
                  "stepfun-image": 6,
                  runway: 7,
                  krea: 8,
                  gemini: 8,
                  "huanke-gemini": 9,
                };
                const crossProviderCandidates = getImageCrossProviderCandidates(allModels, {
                  currentModelId: finalModelId,
                  currentProviderId: alibabaModelConfig?.providerId,
                  providerPriority,
                });

                for (const candidate of crossProviderCandidates) {
                  try {
                    chatApiLogger.info(`[Chat API] 🔁 Cross-provider failover attempt: ${candidate.model.displayName} (${candidate.provider.type})`);
                    if (
                      candidate.provider.type === "fal-image" &&
                      isFalGptImage2EditModelId(
                        String(candidate.model?.modelId || candidate.model?.id || "")
                      )
                    ) {
                      chatApiLogger.info(`[Chat API] Skip async-only failover candidate: ${candidate.model.displayName}`);
                      continue;
                    }

                    const candidateLanguageModel = await getLanguageModelById(candidate.model.id);
                    if (!candidateLanguageModel || typeof (candidateLanguageModel as any).doGenerate !== "function") {
                      chatApiLogger.info(`[Chat API] Skip candidate without doGenerate: ${candidate.model.id}`);
                      continue;
                    }

                    const convertProvider =
                      candidate.provider.type === "bfl-image"
                        ? "bfl-image"
                        : candidate.provider.type === "ruxa-image"
                        ? "ruxa-image"
                        : candidate.provider.type === "fal-image"
                          ? "fal-image"
                          : candidate.provider.type === "openai-image"
                            ? "openai-image"
                          : candidate.provider.type === "stepfun-image"
                            ? "stepfun-image"
                            : candidate.provider.type === "midjourney"
                              ? "midjourney"
                            : candidate.provider.type === "runway"
                              ? "runway"
                            : candidate.provider.type === "krea"
                              ? "krea"
                            : candidate.provider.type === "gemini"
                              ? "gemini"
                              : candidate.provider.type === "huanke-gemini"
                                ? "huanke-gemini"
                                : candidate.provider.type === "volcano-vision"
                                  ? "volcano"
                                  : "alibaba-image";

                    const candidateMessages = await convertMessagesWithImages(
                      messagesForAlibaba,
                      convertProvider
                    );

                    const candidateResult = await (candidateLanguageModel as any).doGenerate({
                      messages: candidateMessages,
                      imageParams:
                        effectiveImageParams || {
                          aspectRatio: defaultImageQualityParams.aspectRatio,
                          imageSize: defaultImageQualityParams.imageSize,
                          imageCount: defaultImageQualityParams.imageCount,
                        },
                      modelDisplayName: candidate.model.displayName,
                      overrideModelId: candidate.model.modelId,
                    });

                    if (candidateResult?.finishReason === "error") {
                      throw new Error(candidateResult.text || "图片生成失败");
                    }

                    imageMarkdown = candidateResult.text || "图片生成失败";
                    usedModelId = candidate.model.modelId;
                    fallbackSuccess = true;
                    chatApiLogger.info(`[Chat API] ✅ Cross-provider failover succeeded: ${candidate.model.displayName} (${candidate.provider.type})`);
                    break;
                  } catch (crossError) {
                    const crossErrorMessage = normalizeFailoverErrorMessage(crossError);
                    if (shouldCooldownImageFallbackModel(crossErrorMessage)) {
                      setImageFallbackModelCooldown(candidate.model.id, crossErrorMessage);
                    }
                    chatApiLogger.error(`[Chat API] ❌ Cross-provider failover failed: ${candidate.model.displayName} (${candidate.provider.type})`, crossError);
                  }
                }
              }
              
              if (!fallbackSuccess) {
                throw primaryError;
              }
            }
            
            chatApiLogger.info("[Chat API] Alibaba generated, length:", imageMarkdown.length);
            chatApiLogger.info("[Chat API] Alibaba used model:", usedModelId);

            const usedModelDisplayName =
              resolveModelDisplayNameByModelId(allModels, usedModelId) ||
              alibabaModelConfig?.displayName ||
              actualModelId;
            const imageMarkdownWithModel = prependImageModelBadge(
              imageMarkdown,
              usedModelDisplayName,
            );
            
            // 生成消息 ID（图片消息）
            const messageId = generateUUID();
            
            // 写入图片消息到流
	            writeAssistantTextChunk(
	              writer,
	              imageMarkdownWithModel,
	              "alibaba:image-result",
	              messageId,
	            );
            if (contextPayload?.source === "canvas") {
              writeCanvasMediaChunk(
                writer,
                {
                  messageId,
                  text: imageMarkdownWithModel,
                  prompt: requestTextContent,
                  sourceImageUrls: requestTargetResolution?.targetImageUrls || [],
                },
                "alibaba:image-canvas-media",
              );
            }
	            
	            // 🆕 图片生成结束标记（成功）
	            writeAssistantTextChunk(
	              writer,
	              "<!-- IMAGE_GENERATION_END -->",
	              "alibaba:image-end-success",
	            );
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "completed",
                  providerType: (languageModel as any).provider,
                  modelName: usedModelDisplayName,
                  imageCount: effectiveImageParams?.imageCount || defaultImageQualityParams.imageCount || 1,
                },
                "alibaba:image-status-completed",
              );
            }
            
            // 保存图片消息到数据库
            try {
              await saveMessages({
                messages: [
                  {
                    id: messageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: imageMarkdownWithModel }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
              chatApiLogger.info("[Chat API] ✅ Alibaba message saved successfully!");
              
              // 提取用户 prompt
              const userPrompt = lastUserMessage?.parts?.find((p): p is { type: "text"; text: string } => p.type === "text")?.text || "";
              
              // 保存图片记录到 GeneratedImage 表
              await saveGeneratedImages(
                imageMarkdownWithModel,
                session.user.id,
                id,
                messageId,
                userPrompt,
                resolveModelRefByRuntimeModelId(
                  allModels,
                  usedModelId,
                  usedModelId === actualModelId ? finalModelId : undefined,
                ),
                {
                  sourceAssetIds: requestTargetResolution?.targetAssetIds,
                  sourceImageUrls: requestTargetResolution?.targetImageUrls,
                  relationType: requestResolvedMediaInput?.hasImage ? "edited_from" : "generated_from",
                  sourceType: "generated",
                  projectId: contextPayload?.projectId || null,
                  optimizedPrompt: smartAutoOptimizedPrompt || userPrompt,
                  requestedImageCount: effectiveImageParams?.imageCount,
                  aspectRatio: effectiveImageParams?.aspectRatio,
                  imageSize: effectiveImageParams?.imageSize,
                },
              );
            } catch (saveError) {
              chatApiLogger.error("[Chat API] ❌ Failed to save Alibaba message:", saveError);
            }
          } catch (error) {
            chatApiLogger.error("[Chat API] Alibaba generation error:", error);
            
            // 返回错误消息
            const errorMessageId = generateUUID();
            const errorText = error instanceof Error ? error.message : "图片生成失败，请稍后重试";
            writeAssistantTextChunk(
              writer,
              errorText,
              "alibaba:error",
              errorMessageId,
            );
            
            // 🆕 图片生成结束标记（失败）
            writeAssistantTextChunk(
              writer,
              "<!-- IMAGE_GENERATION_END -->",
              "alibaba:image-end-failed",
            );
            
            try {
              await saveMessages({
                messages: [
                  {
                    id: errorMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: errorText }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
            } catch (saveError) {
              chatApiLogger.error("[Chat API] Failed to save error message:", saveError);
            }
          } finally {
            stopKeepalive?.();
          }
        },
      });
      
      return createSseResponse(alibabaStream);
    }
    // ========== 阿里云图片生成处理结束 ==========

    // ========== 火山引擎视觉图片生成独立处理 ==========
    if ((languageModel as any).provider === "volcano-vision" && typeof (languageModel as any).doGenerate === "function") {
      chatApiLogger.info("[Chat API] Using Volcano Vision image generation");
      
      // 🆕 检测是否有标注图片，如果有则在消息中注入系统提示
      const hasAnnotation = hasAnnotatedImage(uiMessages);
      let messagesForVolcano = applyOptimizedPromptToLatestUserMessage(
        uiMessagesForModel,
        smartAutoOptimizedPrompt,
        hiddenPromptPrefix,
      );
      const volcanoModelConfig = await getAiModelById({ id: finalModelId });
      const configuredFallbacks = [
        volcanoModelConfig?.fallbackModelId1,
        volcanoModelConfig?.fallbackModelId2,
      ].filter(Boolean) as string[];
      const allModels = await getEnabledAiModelsWithProvider();
      const fallbackCandidates = buildImageFallbackCandidates(allModels, {
        currentProviderId: volcanoModelConfig?.providerId,
        currentModelId: volcanoModelConfig?.id,
        currentModelKey: actualModelId,
        configuredFallbackIds: configuredFallbacks,
      });
      chatApiLogger.info("[Chat API] Volcano fallback candidates:", fallbackCandidates.map((candidate) => `${candidate.model.displayName}(${candidate.provider.type})`));
      
      if (hasAnnotation) {
        chatApiLogger.info("[Chat API] 🎨 Volcano Vision: 检测到标注图片，将注入系统提示");
        // 创建消息副本，修改最后一条用户消息的文本
        messagesForVolcano = messagesForVolcano.map((msg, idx) => {
          if (msg.role === "user" && idx === messagesForVolcano.length - 1) {
            // 修改最后一条用户消息
            const modifiedParts = msg.parts.map((part) => {
              if (part.type === "text" && part.text) {
                return {
                  ...part,
                  text: ANNOTATION_SYSTEM_PROMPT + "\n\n用户请求：" + part.text,
                };
              }
              return part;
            });
            return { ...msg, parts: modifiedParts };
          }
          return msg;
        });
      }

      messagesForVolcano = injectHistoryImagesToLastUserMessage(messagesForVolcano, smartAutoHistoryImages);
      
      const volcanoStream = createUIMessageStream({
        execute: async ({ writer }) => {
          let stopKeepalive: (() => void) | null = null;
          try {
            // 🆕 如果是智能模式且有对话回复，先发送对话消息让用户看到
            const conversationMessage = smartAutoFriendlyMessage || null;
            
            if (conversationMessage) {
              const chatMessageId = generateUUID();
              chatApiLogger.info("[Chat API] 💬 Volcano: Sending conversational reply first:", smartAutoFriendlyMessage);
              
              // 发送带标记的对话消息
              writeAssistantTextChunk(
                writer,
                conversationMessage,
                "volcano:conversation",
                chatMessageId,
              );
              
              // 保存对话消息到数据库（不带标记，纯对话）
              await saveMessages({
                messages: [
                  {
                    id: chatMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: smartAutoFriendlyMessage }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
            }
            
            // 转换消息，火山引擎支持 URL 和 base64
            const modelMessages = await convertMessagesWithImages(messagesForVolcano, "volcano");
            
            const tryGenerateImage = async (modelIdToUse: string, isRetry: boolean) => {
              const result = await (languageModel as any).doGenerate({
                messages: modelMessages,
                imageParams:
                  effectiveImageParams || {
                    aspectRatio: defaultImageQualityParams.aspectRatio,
                    imageSize: defaultImageQualityParams.imageSize,
                    imageCount: defaultImageQualityParams.imageCount,
                  },
                overrideModelId: isRetry ? modelIdToUse : undefined,
              });
              if (result?.finishReason === "error") {
                throw new Error(result.text || "图片生成失败");
              }
              return result.text || "图片生成失败";
            };

            let imageMarkdown = "";
            let usedModelId = actualModelId;

            // 🆕 图片生成真正开始时发出标记（用于前端显示占位图）
	            writeAssistantTextChunk(
	              writer,
	              "<!-- IMAGE_GENERATION_START -->",
	              "volcano:image-start",
	            );
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "processing",
                  providerType: "volcano-vision",
                  modelName: volcanoModelConfig?.displayName || actualModelId,
                  imageCount: effectiveImageParams?.imageCount || defaultImageQualityParams.imageCount || 1,
                },
                "volcano:image-status-start",
              );
            }
	            stopKeepalive = startStreamKeepalive(writer, "volcano-image");
            try {
              imageMarkdown = await tryGenerateImage(actualModelId, false);
	            } catch (primaryError) {
	              chatApiLogger.error("[Chat API] Volcano primary model failed:", primaryError);
	              let fallbackSuccess = false;
              for (const candidate of fallbackCandidates) {
                try {
                  chatApiLogger.info(`[Chat API] 🔄 Volcano fallback model: ${candidate.model.displayName} (${candidate.provider.type})`);
                  const fallbackResult = await generateImageWithFailoverCandidate({
                    candidate,
                    messages: messagesForVolcano,
                    imageParams: effectiveImageParams,
                    fallbackImageParams: {
                      aspectRatio: defaultImageQualityParams.aspectRatio,
                      imageSize: defaultImageQualityParams.imageSize,
                      imageCount: defaultImageQualityParams.imageCount,
                    },
                  });
                  imageMarkdown = fallbackResult.text;
                  usedModelId = fallbackResult.usedModelId;
                  fallbackSuccess = true;
                  chatApiLogger.info(`[Chat API] ✅ Volcano fallback model ${fallbackResult.displayName} succeeded!`);
                  break;
                } catch (fallbackError) {
                  const fallbackErrorMessage = normalizeFailoverErrorMessage(fallbackError);
                  if (shouldCooldownImageFallbackModel(fallbackErrorMessage)) {
                    setImageFallbackModelCooldown(candidate.model.id, fallbackErrorMessage);
                  }
                  chatApiLogger.error(`[Chat API] ❌ Volcano fallback model ${candidate.model.displayName} (${candidate.provider.type}) failed:`, fallbackError);
                }
              }
              if (!fallbackSuccess) {
                const providerPriority: Record<string, number> = {
                  "alibaba-image": 0,
                  "bfl-image": 1,
                  "ruxa-image": 2,
                  "fal-image": 3,
                  "openai-image": 4,
                  "stepfun-image": 5,
                  runway: 6,
                  krea: 7,
                  gemini: 7,
                  "huanke-gemini": 8,
                  "volcano-vision": 9,
                };
                const crossProviderCandidates = getImageCrossProviderCandidates(allModels, {
                  currentModelId: finalModelId,
                  currentProviderId: volcanoModelConfig?.providerId,
                  providerPriority,
                });

                for (const candidate of crossProviderCandidates) {
                  try {
                    chatApiLogger.info(`[Chat API] 🔁 Volcano cross-provider failover attempt: ${candidate.model.displayName} (${candidate.provider.type})`);
                    if (
                      candidate.provider.type === "fal-image" &&
                      isFalGptImage2EditModelId(
                        String(candidate.model?.modelId || candidate.model?.id || "")
                      )
                    ) {
                      chatApiLogger.info(`[Chat API] Skip async-only failover candidate: ${candidate.model.displayName}`);
                      continue;
                    }

                    const candidateLanguageModel = await getLanguageModelById(candidate.model.id);
                    if (!candidateLanguageModel || typeof (candidateLanguageModel as any).doGenerate !== "function") {
                      chatApiLogger.info(`[Chat API] Skip candidate without doGenerate: ${candidate.model.id}`);
                      continue;
                    }

                    const convertProvider =
                      candidate.provider.type === "bfl-image"
                        ? "bfl-image"
                        : candidate.provider.type === "ruxa-image"
                        ? "ruxa-image"
                        : candidate.provider.type === "fal-image"
                          ? "fal-image"
                          : candidate.provider.type === "openai-image"
                            ? "openai-image"
                          : candidate.provider.type === "stepfun-image"
                            ? "stepfun-image"
                            : candidate.provider.type === "midjourney"
                              ? "midjourney"
                            : candidate.provider.type === "runway"
                              ? "runway"
                            : candidate.provider.type === "krea"
                              ? "krea"
                            : candidate.provider.type === "gemini"
                              ? "gemini"
                              : candidate.provider.type === "huanke-gemini"
                                ? "huanke-gemini"
                                : candidate.provider.type === "volcano-vision"
                                  ? "volcano"
                                  : "alibaba-image";

                    const candidateMessages = await convertMessagesWithImages(
                      messagesForVolcano,
                      convertProvider
                    );

                    const candidateResult = await (candidateLanguageModel as any).doGenerate({
                      messages: candidateMessages,
                      imageParams:
                        effectiveImageParams || {
                          aspectRatio: defaultImageQualityParams.aspectRatio,
                          imageSize: defaultImageQualityParams.imageSize,
                          imageCount: defaultImageQualityParams.imageCount,
                        },
                      modelDisplayName: candidate.model.displayName,
                      overrideModelId: candidate.model.modelId,
                    });

                    if (candidateResult?.finishReason === "error") {
                      throw new Error(candidateResult.text || "图片生成失败");
                    }

                    imageMarkdown = candidateResult.text || "图片生成失败";
                    usedModelId = candidate.model.modelId;
                    fallbackSuccess = true;
                    chatApiLogger.info(`[Chat API] ✅ Volcano cross-provider failover succeeded: ${candidate.model.displayName} (${candidate.provider.type})`);
                    break;
                  } catch (crossError) {
                    const crossErrorMessage = normalizeFailoverErrorMessage(crossError);
                    if (shouldCooldownImageFallbackModel(crossErrorMessage)) {
                      setImageFallbackModelCooldown(candidate.model.id, crossErrorMessage);
                    }
                    chatApiLogger.error(`[Chat API] ❌ Volcano cross-provider failover failed: ${candidate.model.displayName} (${candidate.provider.type})`, crossError);
                  }
                }
              }
              if (!fallbackSuccess) {
                throw primaryError;
              }
            }
            chatApiLogger.info("[Chat API] Volcano Vision generated, length:", imageMarkdown.length);
            chatApiLogger.info("[Chat API] Volcano Vision image markdown:", imageMarkdown.substring(0, 200));

            const usedModelDisplayName =
              resolveModelDisplayNameByModelId(allModels, usedModelId) ||
              volcanoModelConfig?.displayName ||
              actualModelId;
            const imageMarkdownWithModel = prependImageModelBadge(
              imageMarkdown,
              usedModelDisplayName,
            );
            
            // 生成消息 ID（图片消息）
            const messageId = generateUUID();
            
            // 写入图片消息到流
	            writeAssistantTextChunk(
	              writer,
	              imageMarkdownWithModel,
	              "volcano:image-result",
	              messageId,
	            );
            if (contextPayload?.source === "canvas") {
              writeCanvasMediaChunk(
                writer,
                {
                  messageId,
                  text: imageMarkdownWithModel,
                  prompt: requestTextContent,
                  sourceImageUrls: requestTargetResolution?.targetImageUrls || [],
                },
                "volcano:image-canvas-media",
              );
            }
	            
	            // 🆕 图片生成结束标记（成功）
	            writeAssistantTextChunk(
	              writer,
	              "<!-- IMAGE_GENERATION_END -->",
	              "volcano:image-end-success",
	            );
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                writer,
                {
                  phase: "completed",
                  providerType: "volcano-vision",
                  modelName: usedModelDisplayName,
                  imageCount: effectiveImageParams?.imageCount || defaultImageQualityParams.imageCount || 1,
                },
                "volcano:image-status-completed",
              );
            }
            
            // 保存图片消息到数据库
            try {
              await saveMessages({
                messages: [
                  {
                    id: messageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: imageMarkdownWithModel }],
                    attachments: [], // 必须提供 attachments 字段（数据库 notNull）
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
              chatApiLogger.info("[Chat API] ✅ Volcano Vision message saved successfully!");
              
              // 提取用户 prompt
              const lastUserMessage = uiMessages.filter((m) => m.role === "user").pop();
              const userPrompt = lastUserMessage?.parts?.find((p): p is { type: "text"; text: string } => p.type === "text")?.text || "";

              // 保存图片记录到 GeneratedImage 表
              await saveGeneratedImages(
                imageMarkdownWithModel,
                session.user.id,
                id,
                messageId,
                userPrompt,
                resolveModelRefByRuntimeModelId(
                  allModels,
                  usedModelId,
                  usedModelId === actualModelId ? finalModelId : undefined,
                ),
                {
                  sourceAssetIds: requestTargetResolution?.targetAssetIds,
                  sourceImageUrls: requestTargetResolution?.targetImageUrls,
                  relationType: requestResolvedMediaInput?.hasImage ? "edited_from" : "generated_from",
                  sourceType: "generated",
                  projectId: contextPayload?.projectId || null,
                  optimizedPrompt: smartAutoOptimizedPrompt || userPrompt,
                  requestedImageCount: effectiveImageParams?.imageCount,
                  aspectRatio: effectiveImageParams?.aspectRatio,
                  imageSize: effectiveImageParams?.imageSize,
                },
              );
            } catch (saveError) {
              chatApiLogger.error("[Chat API] ❌ Failed to save Volcano Vision message to database:", saveError);
              chatApiLogger.error("[Chat API] Message content that failed:", imageMarkdown.substring(0, 300));
            }
          } catch (error) {
            chatApiLogger.error("[Chat API] Volcano Vision generation error:", error);
            const errorMessageId = generateUUID();
            writeAssistantTextChunk(
              writer,
              "图片生成失败，请稍后重试",
              "volcano:error",
              errorMessageId,
            );
            
            // 🆕 图片生成结束标记（失败）
            writeAssistantTextChunk(
              writer,
              "<!-- IMAGE_GENERATION_END -->",
              "volcano:image-end-failed",
            );
            
            // 尝试保存错误消息
            try {
              await saveMessages({
                messages: [
                  {
                    id: errorMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: "图片生成失败，请稍后重试" }],
                    attachments: [], // 必须提供 attachments 字段
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
            } catch (saveError) {
              chatApiLogger.error("[Chat API] Failed to save error message:", saveError);
            }
          } finally {
            stopKeepalive?.();
          }
        },
      });
      
      return createSseResponse(volcanoStream);
    }
    // ========== 火山引擎视觉处理结束 ==========

    // ========== 千问/FAL/RUXA 视频生成独立处理 ==========
    if (
      ["qianwen-video", "fal-video", "ruxa-video", "runway", "krea", "bltcy-video"].includes((languageModel as any).provider) &&
      typeof (languageModel as any).doGenerate === "function"
    ) {
      const currentVideoProvider = (languageModel as any).provider as
        | "qianwen-video"
        | "fal-video"
        | "ruxa-video"
        | "runway"
        | "krea"
        | "bltcy-video";
      chatApiLogger.info(`[Chat API] Using ${currentVideoProvider} video generation`);
      
      const videoGenerationStream = createUIMessageStream({
        execute: async ({ writer }) => {
          try {
            const conversationMessage = smartAutoFriendlyMessage || null;
            if (conversationMessage) {
              const chatMessageId = generateUUID();
              writer.write({
                type: "data-appendMessage",
                data: JSON.stringify({
                  id: chatMessageId,
                  role: "assistant",
                  parts: [{ type: "text", text: conversationMessage }],
                }),
              });

              await saveMessages({
                messages: [
                  {
                    id: chatMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: conversationMessage }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
            }

            const messagesForVideo = injectHistoryImagesToLastUserMessage(
              applyOptimizedPromptToLatestUserMessage(
                uiMessagesForModel,
                smartAutoOptimizedPrompt,
                hiddenPromptPrefix,
              ),
              smartAutoHistoryImages,
            );

            // 千问/FAL 视频直接使用原始 URL，不转换为 base64
            const modelMessages = convertToModelMessages(messagesForVideo);
            chatApiLogger.info(`[Chat API] ${currentVideoProvider} messages prepared, count:`, modelMessages.length);

            let videoMarkdown = "视频生成失败";
            let tempVideoUrl = "";
            let billedModelRefs: string[] = [finalModelId];
            let videoMetadata: Record<string, any> = {
              provider: currentVideoProvider,
              model: finalModelId,
              mode: effectiveVideoParams?.mode,
              resolution: effectiveVideoParams?.resolution,
              ratio: effectiveVideoParams?.ratio,
              duration: effectiveVideoParams?.duration,
              status: "succeeded",
              updatedAt: Date.now(),
            };

            let usedStoryboardPipeline = false;
            if (currentVideoProvider === "ruxa-video") {
              const storyboardConfig = await getVideoStoryboardConfig().catch(() => null);
              if (storyboardConfig?.enabled) {
                const storyboardModelCandidates = await resolveStoryboardModelCandidates(finalModelId);
                const runtimeModelId = String((languageModel as any).modelId || "").trim();
                const selectedModelId =
                  runtimeModelId ||
                  storyboardModelCandidates.find((item) => item.id === finalModelId)?.modelId ||
                  "";

                const storyboardResult = await runRuxaNineGridPipeline({
                  userId: session.user.id,
                  chatId: id,
                  modelMessages: modelMessages as any,
                  selectedModelId,
                  selectedModelRef: finalModelId,
                  modelCandidates: storyboardModelCandidates,
                  videoParams: effectiveVideoParams as any,
                  config: storyboardConfig,
                  doGenerate: (input) =>
                    (languageModel as any).doGenerate({
                      messages: input.messages,
                      videoParams: input.videoParams,
                      overrideModelId: input.overrideModelId,
                    }),
                  onProgress: (event) => {
                    safeWriteStreamChunk(
                      writer,
                      {
                        type: "data-videoStoryboard",
                        data: JSON.stringify(event),
                      },
                      `ruxa-video:storyboard:${event.stage}`,
                    );
                  },
                });

                if (storyboardResult.triggered) {
                  usedStoryboardPipeline = true;
                  videoMarkdown = storyboardResult.markdown || "视频生成失败，请稍后重试";
                  tempVideoUrl = storyboardResult.videoUrls?.[0] || "";
                  const isAwaitingConfirmation =
                    storyboardResult.reason === "awaiting_user_confirmation";
                  billedModelRefs =
                    storyboardResult.modelRefs && storyboardResult.modelRefs.length > 0
                      ? storyboardResult.modelRefs
                      : [finalModelId];

                  const successCount = storyboardResult.videoUrls?.length || 0;
                  videoMetadata = {
                    ...videoMetadata,
                    ...(storyboardResult.metadata || {}),
                    status: isAwaitingConfirmation
                      ? "awaiting_user_confirmation"
                      : successCount > 0
                        ? "succeeded"
                        : "failed",
                    storyboard: {
                      enabled: true,
                      taskId: storyboardResult.taskId,
                      confidence: storyboardResult.confidence,
                      successCount,
                      awaitingConfirmation: isAwaitingConfirmation,
                    },
                    updatedAt: Date.now(),
                  };
                }
              }
            }

            if (!usedStoryboardPipeline) {
              const result = await (languageModel as any).doGenerate({
                messages: modelMessages,
                videoParams: effectiveVideoParams,
              });

              if (result?.finishReason === "error") {
                throw new Error(result.text || "视频生成失败");
              }

              videoMarkdown = result.text || "视频生成失败";
              tempVideoUrl = extractVideoUrlFromText(videoMarkdown) || "";
            }

            chatApiLogger.info(`[Chat API] ${currentVideoProvider} video generated, length:`, videoMarkdown.length);
            
            // 生成一个统一的消息 ID
            const messageId = generateUUID();
            
            // 写入消息到流
            writer.write({
              type: "data-appendMessage",
              data: JSON.stringify({
                id: messageId,
                role: "assistant",
                parts: [{ type: "text", text: videoMarkdown }],
                attachments: [],
              }),
            });
            
            // 保存消息到数据库
            try {
              await saveMessages({
                messages: [
                  {
                    id: messageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: videoMarkdown }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: tempVideoUrl ? "temporary" : null,
                    temporaryVideoUrl: tempVideoUrl || null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: videoMetadata as any,
                  },
                ],
              });
              const storyboardTaskId = String((videoMetadata as any)?.taskId || "").trim();
              if (storyboardTaskId) {
                await attachVideoStoryboardTaskMessage({
                  taskId: storyboardTaskId,
                  messageId,
                }).catch((taskAttachError) => {
                  chatApiLogger.warn("[Chat API] Failed to attach storyboard task with message:", taskAttachError);
                });
              }
              chatApiLogger.info(`[Chat API] ✅ ${currentVideoProvider} video message saved successfully!`);

              if ((videoMetadata as any)?.storyboard?.enabled) {
                try {
                  const storyboardGridType = String((videoMetadata as any)?.gridType || "").trim();
                  const storyboardShotCount = Number((videoMetadata as any)?.shotCount || 0);
                  await persistStoryboardAssistantTurn({
                    userId: session.user.id,
                    chatId: id,
                    projectId: contextPayload?.projectId || null,
                    lastMessageId: messageId,
                    text: requestTextContent,
                    storyboardGridType:
                      storyboardGridType === "grid_2x2" ||
                      storyboardGridType === "grid_3x2" ||
                      storyboardGridType === "grid_3x3"
                        ? (storyboardGridType as "grid_2x2" | "grid_3x2" | "grid_3x3")
                        : undefined,
                    storyboardShotCount:
                      storyboardShotCount === 4 ||
                      storyboardShotCount === 6 ||
                      storyboardShotCount === 9
                        ? storyboardShotCount
                        : undefined,
                  });
                } catch (storyboardMemoryPersistError) {
                  chatApiLogger.warn("[Chat API] Failed to persist storyboard memory after assistant response:", storyboardMemoryPersistError);
                }
              } else {
                try {
                  await persistVideoGenerationCompletedTurn({
                    userId: session.user.id,
                    chatId: id,
                    projectId: contextPayload?.projectId || null,
                    messageId,
                    text: requestTextContent,
                    source: "native_video_provider",
                    providerType: currentVideoProvider,
                    modelRef: finalModelId,
                    mode:
                      typeof effectiveVideoParams?.mode === "string"
                        ? effectiveVideoParams.mode
                        : undefined,
                    taskId: storyboardTaskId || undefined,
                    status:
                      typeof (videoMetadata as any)?.status === "string"
                        ? (videoMetadata as any).status
                        : tempVideoUrl
                          ? "completed"
                          : undefined,
                    temporaryVideoUrl: tempVideoUrl || undefined,
                  });
                } catch (videoWorkflowPersistError) {
                  chatApiLogger.warn("[Chat API] Failed to persist native video workflow state:", videoWorkflowPersistError);
                }
              }
              const shouldConsumeVideoPoints =
                tempVideoUrl &&
                (videoMetadata as any)?.status !== "awaiting_user_confirmation";
              if (shouldConsumeVideoPoints) {
                await consumeGeneratedVideoPoints({
                  userId: session.user.id,
                  chatId: id,
                  messageId,
                  modelRefs: billedModelRefs,
                  duration: Number(effectiveVideoParams?.duration) || undefined,
                  resolution:
                    String(effectiveVideoParams?.resolution || "").trim() ||
                    undefined,
                });
              }

              if (tempVideoUrl) {
                scheduleVideoArchive({
                  chatId: id,
                  messageId,
                  text: videoMarkdown,
                  temporaryVideoUrl: tempVideoUrl,
                  taskId: messageId,
                  metadata: videoMetadata,
                });
              }
            } catch (saveError) {
              chatApiLogger.error(`[Chat API] ❌ Failed to save ${currentVideoProvider} video message:`, saveError);
            }
          } catch (error) {
            chatApiLogger.error(`[Chat API] ${currentVideoProvider} video generation error:`, error);
            const errorMessageId = generateUUID();
            const errorText = "视频生成失败，请稍后重试";
            writer.write({
              type: "data-appendMessage",
              data: JSON.stringify({
                id: errorMessageId,
                role: "assistant",
                parts: [{ type: "text", text: errorText }],
                attachments: [],
              }),
            });
            try {
              await saveMessages({
                messages: [
                  {
                    id: errorMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: errorText }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: null,
                  },
                ],
              });
              await persistVideoGenerationFailedTurn({
                userId: session.user.id,
                chatId: id,
                projectId: contextPayload?.projectId || null,
                messageId: errorMessageId,
                text: requestTextContent,
                source: "native_video_provider",
                providerType: currentVideoProvider,
                modelRef: finalModelId,
                mode:
                  typeof effectiveVideoParams?.mode === "string"
                    ? effectiveVideoParams.mode
                    : undefined,
                status: "failed",
                error: error instanceof Error ? error.message : String(error),
              });
            } catch (videoFailurePersistError) {
              chatApiLogger.warn("[Chat API] Failed to persist native video failure state:", videoFailurePersistError);
            }
          }
        },
      });
      
      return createSseResponse(videoGenerationStream);
    }
    // ========== 千问/FAL/RUXA 视频处理结束 ==========

    let stopStreamKeepalive: (() => void) | null = null;
    const stream = createUIMessageStream({
      execute: async ({ writer: dataStream }) => {
        const stopDefaultKeepalive = startStreamKeepalive(
          dataStream,
          "chat-default",
          DEFAULT_STREAM_KEEPALIVE_INTERVAL_MS
        );
        stopStreamKeepalive = stopDefaultKeepalive;
        setConversationStateProtocolEventObserver((event) => {
          writeProtocolDebugChunk(
            dataStream,
            Boolean(debugProtocol),
            {
              phase: "event",
              type: event.type,
              payload: event.payload,
            },
            `protocol:event:${event.type}`
          );
        });
        safeWriteStreamChunk(
          dataStream,
          {
            type: "data-keepalive",
            data: JSON.stringify({ ts: Date.now(), label: "chat-default:init" }),
          },
          "chat-default:init"
        );
        writeProtocolDebugChunk(
          dataStream,
          Boolean(debugProtocol),
          {
            phase: "request",
            chatId: id,
            selectedChatModel,
            hasHiddenPrompt: Boolean(hiddenPrompt),
            hasAutoContext: Boolean(autoContext),
          },
          "protocol:request"
        );
        writeCurrentAgentTargetLockChunk(dataStream, "chat-default:target-lock");
        for (const event of pendingProtocolDebugEvents) {
          writeProtocolDebugChunk(
            dataStream,
            Boolean(debugProtocol),
            {
              phase: event.phase,
              ...event.payload,
            },
            `protocol:${event.phase}`
          );
        }
        try {
          // 构建工具对象，只包含启用的工具
          const tools: any = {};
          const activeTools: string[] = [];

        if (enabledTools.includes("getWeather")) {
          tools.getWeather = getWeather;
          activeTools.push("getWeather");
        }
        if (enabledTools.includes("createDocument")) {
          tools.createDocument = createDocument({ session, dataStream });
          activeTools.push("createDocument");
        }
        if (enabledTools.includes("updateDocument")) {
          tools.updateDocument = updateDocument({ session, dataStream });
          activeTools.push("updateDocument");
        }
        if (enabledTools.includes("requestSuggestions")) {
          tools.requestSuggestions = requestSuggestions({
            session,
            dataStream,
          });
          activeTools.push("requestSuggestions");
        }
        const shouldEnableGenerateVideoTool =
          enabledTools.includes("generateVideo") &&
          (!shouldRunAgentConversation || allowAgentVideoGeneration);
        if (shouldEnableGenerateVideoTool) {
          tools.generateVideo = generateVideo({ dataStream });
          activeTools.push("generateVideo");
        } else if (enabledTools.includes("generateVideo") && shouldRunAgentConversation) {
          chatApiLogger.info("[Smart Auto Mode] 🚫 generateVideo tool disabled (manual video mode not selected)");
        }

        chatApiLogger.info("[Chat API] Calling streamText with model:", (languageModel as any).modelId, (languageModel as any).provider); // 调试日志
        chatApiLogger.info("[Chat API] Provider type:", (languageModel as any).provider); // 调试日志

        // 转换消息，对于 Gemini 和千问视频将图片 URL 转换为 base64
        const convertedMessages = await convertMessagesWithImages(
          injectHistoryImagesToLastUserMessage(uiMessagesForModel, smartAutoHistoryImages),
          {
            providerType: (languageModel as any).provider || "",
            providerBaseUrl: currentProviderConfig?.baseUrl || null,
            modelId: currentModelConfig?.modelId || actualModelId,
            displayName: currentModelConfig?.displayName || actualModelId,
            forceInlineImageUrls: shouldForceInlineVisionInputs({
              providerType: resolvedProviderType || currentProviderConfig?.type || runtimeProviderType,
              providerBaseUrl: currentProviderConfig?.baseUrl || null,
              modelId: currentModelConfig?.modelId || actualModelId,
              displayName: currentModelConfig?.displayName || actualModelId,
            }),
            loggerPrefix: "[Chat API] Stream text vision inline",
          }
        );
        chatApiLogger.info("[Chat API] Messages converted, count:", convertedMessages.length); // 调试日志

        // 🆕 检测是否是视频模型
        const providerType = (languageModel as any).provider;
        const effectiveProviderType = resolvedProviderType || providerType;
        chatApiLogger.info("[Chat API] Provider type for tool detection:", {
          runtime: providerType,
          resolved: resolvedProviderType,
          effective: effectiveProviderType,
        });
        const isVolcanoVideoModel =
          effectiveProviderType === "volcano-video" ||
          effectiveProviderType === "doubao-video" ||
          actualModelId.includes("seedance");
        const isOpenAICompatImageModel =
          resolvedModelSupportsImageGen &&
          providerType === "openai.chat" &&
          !isVolcanoVideoModel;
        chatApiLogger.info("[Chat API] Is volcano video model:", isVolcanoVideoModel);

        // 🆕 处理 OpenAI 兼容的生图模型输出（防止返回 data:image;base64 原文）
        if (isOpenAICompatImageModel) {
          chatApiLogger.info("[Chat API] Using generateText for OpenAI-compatible image model");
          const configuredFallbacks = [
            currentModelConfig?.fallbackModelId1,
            currentModelConfig?.fallbackModelId2,
          ].filter(Boolean) as string[];
          const allModels = await getEnabledAiModelsWithProvider();
          const fallbackCandidates = buildImageFallbackCandidates(allModels, {
            currentProviderId: currentModelConfig?.providerId,
            currentModelId: currentModelConfig?.id,
            currentModelKey: actualModelId,
            configuredFallbackIds: configuredFallbacks,
          });
          chatApiLogger.info("[Chat API] OpenAI-compatible fallback candidates:", fallbackCandidates.map((candidate) => `${candidate.model.displayName}(${candidate.provider.type})`));

          const lastUserMessage = uiMessagesForModel.filter((m) => m.role === "user").pop();
          let messagesForCrossProvider = lastUserMessage ? [lastUserMessage] : uiMessagesForModel;
          messagesForCrossProvider = applyOptimizedPromptToLatestUserMessage(
            messagesForCrossProvider,
            smartAutoOptimizedPrompt,
            hiddenPromptPrefix,
          );
          messagesForCrossProvider = injectHistoryImagesToLastUserMessage(
            messagesForCrossProvider,
            smartAutoHistoryImages
          );

	          // 生成开始标记
	          dataStream.write({
	            type: "data-appendMessage",
	            data: JSON.stringify({
	              id: generateUUID(),
	              role: "assistant",
	              parts: [{ type: "text", text: "<!-- IMAGE_GENERATION_START -->" }],
	            }),
	          });
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                dataStream as unknown as StreamWriter,
                {
                  phase: "processing",
                  providerType: currentModelConfig?.providerId ? resolvedProviderType || providerType : providerType,
                  modelName: currentModelConfig?.displayName || actualModelId,
                  imageCount: effectiveImageParams?.imageCount || 1,
                },
                "openai-compat:image-status-start",
              );
            }

          try {
            const tryGenerateWithOpenAICompatModel = async (modelToUse: any) => {
              const imageRequestTimeoutMs = 180_000;
              const generated = await generateText({
                model: modelToUse,
                system: systemPrompt({ selectedChatModel: finalModelId, requestHints }),
                messages: convertedMessages,
                abortSignal: AbortSignal.timeout(imageRequestTimeoutMs),
              });

              const rawText = generated.text?.trim() || "图片生成失败，请稍后重试";
              return normalizeAssistantImageMarkdown(
                rawText,
                effectiveImageParams?.imageSize || "2K"
              );
            };

            let normalizedText = "";
            let usedModelId = actualModelId;

            try {
              normalizedText = await tryGenerateWithOpenAICompatModel(languageModel);
	            } catch (primaryError) {
	              chatApiLogger.error("[Chat API] OpenAI-compatible primary model failed:", primaryError);
	
	              let fallbackSuccess = false;
              for (const candidate of fallbackCandidates) {
                try {
                  chatApiLogger.info(`[Chat API] 🔄 OpenAI-compatible fallback model: ${candidate.model.displayName} (${candidate.provider.type})`);
                  const shouldUseOpenAICompatFallback =
                    candidate.sameProvider &&
                    !IMAGE_FAILOVER_PROVIDER_ALLOWLIST.has(String(candidate.provider?.type || ""));

                  if (shouldUseOpenAICompatFallback) {
                    const fallbackRuntimeModelId = String(
                      candidate.model?.modelId || candidate.model?.id || ""
                    );
                    const fallbackLanguageModel = await getLanguageModelById(
                      finalModelId,
                      fallbackRuntimeModelId
                    );
                    if (!fallbackLanguageModel) {
                      chatApiLogger.info(`[Chat API] Skip unavailable OpenAI-compatible fallback model: ${fallbackRuntimeModelId}`);
                      continue;
                    }
                    normalizedText = await tryGenerateWithOpenAICompatModel(fallbackLanguageModel);
                    usedModelId = fallbackRuntimeModelId;
                  } else {
                    const fallbackResult = await generateImageWithFailoverCandidate({
                      candidate,
                      messages: messagesForCrossProvider,
                      imageParams: effectiveImageParams,
                      fallbackImageParams: {
                        aspectRatio: defaultImageQualityParams.aspectRatio,
                        imageSize: defaultImageQualityParams.imageSize,
                        imageCount: defaultImageQualityParams.imageCount,
                      },
                    });
                    normalizedText = fallbackResult.text;
                    usedModelId = fallbackResult.usedModelId;
                  }
                  fallbackSuccess = true;
                  chatApiLogger.info(`[Chat API] ✅ OpenAI-compatible fallback model ${candidate.model.displayName} succeeded!`);
                  break;
                } catch (fallbackError) {
                  const fallbackErrorMessage = normalizeFailoverErrorMessage(fallbackError);
                  if (shouldCooldownImageFallbackModel(fallbackErrorMessage)) {
                    setImageFallbackModelCooldown(candidate.model.id, fallbackErrorMessage);
                  }
                  chatApiLogger.error(`[Chat API] ❌ OpenAI-compatible fallback model ${candidate.model.displayName} (${candidate.provider.type}) failed:`, fallbackError);
                }
              }

              if (!fallbackSuccess) {
                const providerPriority: Record<string, number> = {
                  "volcano-vision": 0,
                  "alibaba-image": 1,
                  "bfl-image": 2,
                  "ruxa-image": 3,
                  "fal-image": 4,
                  "openai-image": 5,
                  "stepfun-image": 6,
                  runway: 7,
                  krea: 8,
                  gemini: 8,
                  "huanke-gemini": 9,
                };
                const crossProviderCandidates = getImageCrossProviderCandidates(allModels, {
                  currentModelId: finalModelId,
                  currentProviderId: currentModelConfig?.providerId,
                  providerPriority,
                });

                for (const candidate of crossProviderCandidates) {
                  try {
                    chatApiLogger.info(`[Chat API] 🔁 OpenAI-compatible cross-provider failover: ${candidate.model.displayName} (${candidate.provider.type})`);
                    if (
                      candidate.provider.type === "fal-image" &&
                      isFalGptImage2EditModelId(
                        String(candidate.model?.modelId || candidate.model?.id || "")
                      )
                    ) {
                      chatApiLogger.info(`[Chat API] Skip async-only failover candidate: ${candidate.model.displayName}`);
                      continue;
                    }

                    const candidateLanguageModel = await getLanguageModelById(candidate.model.id);
                    if (
                      !candidateLanguageModel ||
                      typeof (candidateLanguageModel as any).doGenerate !== "function"
                    ) {
                      chatApiLogger.info(`[Chat API] Skip cross-provider candidate without doGenerate: ${candidate.model.id}`);
                      continue;
                    }

                    const convertProvider =
                      candidate.provider.type === "bfl-image"
                        ? "bfl-image"
                        : candidate.provider.type === "ruxa-image"
                        ? "ruxa-image"
                        : candidate.provider.type === "fal-image"
                          ? "fal-image"
                          : candidate.provider.type === "openai-image"
                            ? "openai-image"
                          : candidate.provider.type === "stepfun-image"
                            ? "stepfun-image"
                            : candidate.provider.type === "midjourney"
                              ? "midjourney"
                            : candidate.provider.type === "runway"
                              ? "runway"
                            : candidate.provider.type === "krea"
                              ? "krea"
                            : candidate.provider.type === "gemini"
                              ? "gemini"
                              : candidate.provider.type === "huanke-gemini"
                                ? "huanke-gemini"
                                : candidate.provider.type === "volcano-vision"
                                  ? "volcano"
                                  : "alibaba-image";

                    const candidateMessages = await convertMessagesWithImages(
                      messagesForCrossProvider,
                      convertProvider
                    );

                    const candidateResult = await (candidateLanguageModel as any).doGenerate({
                      messages: candidateMessages,
                      imageParams:
                        effectiveImageParams || {
                          aspectRatio: defaultImageQualityParams.aspectRatio,
                          imageSize: defaultImageQualityParams.imageSize,
                          imageCount: defaultImageQualityParams.imageCount,
                        },
                      modelDisplayName: candidate.model.displayName,
                      overrideModelId: candidate.model.modelId,
                    });

                    if (candidateResult?.finishReason === "error") {
                      throw new Error(candidateResult.text || "图片生成失败");
                    }

                    normalizedText = candidateResult.text || "图片生成失败";
                    usedModelId = candidate.model.modelId;
                    fallbackSuccess = true;
                    chatApiLogger.info(`[Chat API] ✅ OpenAI-compatible cross-provider failover succeeded: ${candidate.model.displayName} (${candidate.provider.type})`);
                    break;
                  } catch (crossError) {
                    const crossErrorMessage = normalizeFailoverErrorMessage(crossError);
                    if (shouldCooldownImageFallbackModel(crossErrorMessage)) {
                      setImageFallbackModelCooldown(candidate.model.id, crossErrorMessage);
                    }
                    chatApiLogger.error(`[Chat API] ❌ OpenAI-compatible cross-provider failover failed: ${candidate.model.displayName} (${candidate.provider.type})`, crossError);
                  }
                }
              }

              if (!fallbackSuccess) {
                throw primaryError;
              }
            }

            const usedModelDisplayName =
              resolveModelDisplayNameByModelId(allModels, usedModelId) ||
              currentModelConfig?.displayName ||
              actualModelId;
            const normalizedTextWithModel = prependImageModelBadge(
              normalizedText,
              usedModelDisplayName,
            );

            const messageId = generateUUID();
	            dataStream.write({
	              type: "data-appendMessage",
	              data: JSON.stringify({
	                id: messageId,
	                role: "assistant",
	                parts: [{ type: "text", text: normalizedTextWithModel }],
	              }),
	            });
            if (contextPayload?.source === "canvas") {
              writeCanvasMediaChunk(
                dataStream as unknown as StreamWriter,
                {
                  messageId,
                  text: normalizedTextWithModel,
                  prompt: requestTextContent,
                  sourceImageUrls: requestTargetResolution?.targetImageUrls || [],
                },
                "openai-compat:image-canvas-media",
              );
            }

	            // 生成结束标记
	            dataStream.write({
	              type: "data-appendMessage",
              data: JSON.stringify({
                id: generateUUID(),
                role: "assistant",
	                parts: [{ type: "text", text: "<!-- IMAGE_GENERATION_END -->" }],
	              }),
	            });
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                dataStream as unknown as StreamWriter,
                {
                  phase: "completed",
                  providerType: resolvedProviderType || providerType,
                  modelName: usedModelDisplayName,
                  imageCount: effectiveImageParams?.imageCount || 1,
                },
                "openai-compat:image-status-completed",
              );
            }

            await saveMessages({
              messages: [
                {
                  id: messageId,
                  role: "assistant",
                  parts: [{ type: "text", text: normalizedTextWithModel }],
                  createdAt: new Date(),
                  attachments: [],
                  chatId: id,
                  videoStorageStatus: null,
                  temporaryVideoUrl: null,
                  permanentVideoUrl: null,
                  archivedAt: null,
                  videoMetadata: null,
                },
              ],
            });

            const latestUserMessage = uiMessages.filter((m) => m.role === "user").pop();
            const userPrompt =
              latestUserMessage?.parts?.find(
                (p): p is { type: "text"; text: string } => p.type === "text"
              )?.text || "";
            await saveGeneratedImages(
              normalizedTextWithModel,
              session.user.id,
              id,
              messageId,
              userPrompt,
              resolveModelRefByRuntimeModelId(
                allModels,
                usedModelId,
                usedModelId === actualModelId ? finalModelId : undefined,
              ),
              {
                sourceAssetIds: requestTargetResolution?.targetAssetIds,
                sourceImageUrls: requestTargetResolution?.targetImageUrls,
                relationType: requestResolvedMediaInput?.hasImage ? "edited_from" : "generated_from",
                sourceType: "generated",
                projectId: contextPayload?.projectId || null,
                optimizedPrompt: smartAutoOptimizedPrompt || userPrompt,
                requestedImageCount: effectiveImageParams?.imageCount,
                aspectRatio: effectiveImageParams?.aspectRatio,
                imageSize: effectiveImageParams?.imageSize,
              },
            );
            return;
          } catch (error) {
            chatApiLogger.error("[Chat API] OpenAI-compatible image model generation error:", error);

            const errorMessageId = generateUUID();
            const errorText =
              error instanceof Error ? error.message : "图片生成失败，请稍后重试";

            dataStream.write({
              type: "data-appendMessage",
              data: JSON.stringify({
                id: errorMessageId,
                role: "assistant",
                parts: [{ type: "text", text: errorText }],
              }),
            });
	            dataStream.write({
	              type: "data-appendMessage",
	              data: JSON.stringify({
	                id: generateUUID(),
	                role: "assistant",
	                parts: [{ type: "text", text: "<!-- IMAGE_GENERATION_END -->" }],
	              }),
	            });
            if (contextPayload?.source === "canvas") {
              writeImageGenerationStatusChunk(
                dataStream as unknown as StreamWriter,
                {
                  phase: "failed",
                  providerType: resolvedProviderType || providerType,
                  modelName: currentModelConfig?.displayName || actualModelId,
                  imageCount: effectiveImageParams?.imageCount || 1,
                },
                "openai-compat:image-status-failed",
              );
            }

            await saveMessages({
              messages: [
                {
                  id: errorMessageId,
                  role: "assistant",
                  parts: [{ type: "text", text: errorText }],
                  createdAt: new Date(),
                  attachments: [],
                  chatId: id,
                  videoStorageStatus: null,
                  temporaryVideoUrl: null,
                  permanentVideoUrl: null,
                  archivedAt: null,
                  videoMetadata: null,
                },
              ],
            });
            return;
          }
        }

        // 🎬 视频模型使用专门的生成流程
        if (isVolcanoVideoModel) {
          chatApiLogger.info("[Chat API] Using video generation API");
          
          // 导入视频生成函数
          const { doGenerateStream } = await import("@/lib/ai/providers/volcano-video");

          const conversationMessage = smartAutoFriendlyMessage || null;
          if (conversationMessage) {
            const chatMessageId = generateUUID();
            dataStream.write({
              type: "data-appendMessage",
              data: JSON.stringify({
                id: chatMessageId,
                role: "assistant",
                parts: [{ type: "text", text: conversationMessage }],
                attachments: [],
              }),
            });

            await saveMessages({
              messages: [
                {
                  id: chatMessageId,
                  chatId: id,
                  role: "assistant",
                  parts: [{ type: "text", text: conversationMessage }],
                  attachments: [],
                  createdAt: new Date(),
                  videoStorageStatus: null,
                  temporaryVideoUrl: null,
                  permanentVideoUrl: null,
                  archivedAt: null,
                  videoMetadata: null,
                },
              ],
            });
          }

          const messagesForVideo = injectHistoryImagesToLastUserMessage(
            applyOptimizedPromptToLatestUserMessage(
              uiMessagesForModel,
              smartAutoOptimizedPrompt,
              hiddenPromptPrefix,
            ),
            smartAutoHistoryImages,
          );
          
          // 从最后一条用户消息中提取提示词和图片
          const lastUserMessage = messagesForVideo.filter(m => m.role === "user").pop();
          let prompt = "";
          const imageUrls: string[] = [];
          const summarizeImageRef = (rawUrl: string) => {
            const trimmed = String(rawUrl || "").trim();
            if (!trimmed) return "";
            if (trimmed.startsWith("data:image/")) {
              return `data:image(base64,${trimmed.length} chars)`;
            }
            try {
              const parsed = new URL(trimmed);
              return `${parsed.origin}${parsed.pathname}`;
            } catch {
              return trimmed.slice(0, 120);
            }
          };
          
          if (lastUserMessage) {
            // 🆕 处理 parts 数组（AI SDK v4 格式）
            if ((lastUserMessage as any).parts && Array.isArray((lastUserMessage as any).parts)) {
              chatApiLogger.info("[Chat API] Video input parts:", (lastUserMessage as any).parts.length);
              
              for (const part of (lastUserMessage as any).parts) {
                if (part.type === "text" && part.text) {
                  // 提取文本
                  prompt += part.text;
                } else if (part.type === "file" && part.url && part.mediaType?.startsWith("image/")) {
                  // 提取图片
                  imageUrls.push(part.url);
                }
              }
            }
            // 备用方案1：content 字符串/数组
            const legacyContent = (lastUserMessage as any).content;
            if (typeof legacyContent === "string") {
              prompt = legacyContent;
            } else if (Array.isArray(legacyContent)) {
              for (const part of legacyContent) {
                if (typeof part === "string") {
                  prompt += part;
                } else if (part.type === "text") {
                  prompt += part.text;
                } else if (part.type === "image" && (part as any).image) {
                  imageUrls.push((part as any).image);
                }
              }
            } else if ((lastUserMessage as any).experimental_attachments) {
              // 备用方案2：experimental_attachments
              for (const attachment of (lastUserMessage as any).experimental_attachments) {
                if (attachment.url && attachment.contentType?.startsWith("image/")) {
                  imageUrls.push(attachment.url);
                }
              }
            }
          }
          
          chatApiLogger.info("[Chat API] Video input extracted:", {
            promptLength: prompt.trim().length,
            imageCount: imageUrls.length,
            imageRefs: imageUrls.slice(0, 4).map(summarizeImageRef),
          });
          
          const videoMessageId = generateUUID();
          const videoStartAt = Date.now();
          const baseVideoMetadata: Record<string, any> = {
            provider: effectiveProviderType || "volcano-video",
            mode: effectiveVideoParams?.mode || "text-to-video",
            resolution: effectiveVideoParams?.resolution || "720p",
            ratio: effectiveVideoParams?.ratio || "16:9",
            duration: effectiveVideoParams?.duration || 5,
            status: "queued",
            startedAt: videoStartAt,
            updatedAt: videoStartAt,
          };

          try {
            chatApiLogger.info("[Chat API] Video generation params:", {
              promptLength: prompt.trim().length,
              imageCount: imageUrls.length,
              videoParams: effectiveVideoParams,
            });

            const videoMode = (effectiveVideoParams?.mode || "text-to-video") as VideoModeType;

            // 🆕 重新执行子模型选择逻辑，确定要使用的模型 UUID
            let videoModelId = finalModelId; // 默认使用选择的模型 ID

            // 检查是否是主模型，需要选择子模型（仅 volcano-video 支持子模型）
            const selectedModelData = await getAiModelById({ id: finalModelId });
            const selectedModelProvider = selectedModelData
              ? await getAiProviderById({ id: selectedModelData.providerId }).catch(() => null)
              : null;
            if (
              selectedModelData &&
              !selectedModelData.isSubModel &&
              selectedModelProvider?.type === "volcano-video"
            ) {
              const videoSubModels = await getSubModelsByParentModelId(finalModelId);
              chatApiLogger.info(`[Chat API] Video: Found ${videoSubModels.length} sub-models for master model`);

              if (videoSubModels.length > 0) {
                const matchedModel = selectBestVideoSubModelForMode(videoSubModels as any, videoMode);

                if (matchedModel) {
                  videoModelId = matchedModel.model.id;
                  chatApiLogger.info(`[Chat API] Video: Selected sub-model ${matchedModel.model.displayName} (${matchedModel.model.modelId}) for mode ${videoMode}`);
                } else {
                  chatApiLogger.info(`[Chat API] Video: No compatible sub-model found for mode ${videoMode}, keep current model`);
                }
              }
            }

            chatApiLogger.info("[Chat API] Getting model config for:", videoModelId);
            const aiModelData = await getAiModelById({ id: videoModelId });
            if (!aiModelData) {
              throw new Error("视频模型配置未找到");
            }

            // 若用户手动选了不兼容模式的子模型，自动回退到同父模型兼容子模型
            const selectedSupportsMode = getSupportedVideoModesForModel(aiModelData as any).includes(videoMode);
            if (!selectedSupportsMode) {
              let fallbackModel: { model: any } | null = null;

              if (aiModelData.parentModelId) {
                const siblingSubModels = await getSubModelsByParentModelId(aiModelData.parentModelId);
                fallbackModel = selectBestVideoSubModelForMode(siblingSubModels as any, videoMode);
              } else if (selectedModelProvider?.type === "volcano-video") {
                const enabledModels = await getEnabledAiModelsWithProvider();
                const sameProviderModels = enabledModels
                  .filter(
                    ({ model, provider }) =>
                      provider.type === "volcano-video" &&
                      model.isEnabled &&
                      model.id !== aiModelData.id,
                  )
                  .map(({ model }) => ({ model }));
                fallbackModel = selectBestVideoSubModelForMode(sameProviderModels as any, videoMode);
              }

              if (fallbackModel) {
                chatApiLogger.warn(`[Chat API] Video: Model ${aiModelData.modelId} does not support ${videoMode}, fallback to ${fallbackModel.model.modelId}`);
                videoModelId = fallbackModel.model.id;
              }
            }

            const finalVideoModelData = videoModelId === aiModelData.id
              ? aiModelData
              : await getAiModelById({ id: videoModelId });
            if (!finalVideoModelData) {
              throw new Error("视频模型配置未找到");
            }

            // 如果是子模型，获取父模型的 Provider 配置
            let providerModelData = finalVideoModelData;
            if (finalVideoModelData.isSubModel && finalVideoModelData.parentModelId) {
              chatApiLogger.info("[Chat API] This is a sub-model, getting parent model config:", finalVideoModelData.parentModelId);
              const parentModel = await getAiModelById({ id: finalVideoModelData.parentModelId });
              if (parentModel) {
                providerModelData = parentModel;
              }
            }

            chatApiLogger.info("[Chat API] Getting provider config for:", providerModelData.providerId);
            const providerData = await getAiProviderById({ id: providerModelData.providerId });
            if (!providerData) {
              throw new Error("Provider 配置未找到");
            }

            const actualVideoModelId = finalVideoModelData.modelId;

            // 构建视频生成选项
            const videoOptions: any = {
              model: actualVideoModelId,
              prompt: prompt || "生成视频",
              mode: videoMode,
              resolution: effectiveVideoParams?.resolution || "720p",
              ratio: effectiveVideoParams?.ratio || "16:9",
              duration: effectiveVideoParams?.duration || 5,
              fps: effectiveVideoParams?.fps || 24,
              cameraMove: effectiveVideoParams?.cameraMove || "none",
              cameraFixed: effectiveVideoParams?.cameraFixed || false,
              watermark: effectiveVideoParams?.watermark || false,
              seed: effectiveVideoParams?.seed,
            };

            // 根据模式添加图片
            if (videoOptions.mode === "first-frame" && imageUrls[0]) {
              videoOptions.firstFrameImage = imageUrls[0];
            } else if (videoOptions.mode === "first-last-frame" && imageUrls.length >= 2) {
              videoOptions.firstFrameImage = imageUrls[0];
              videoOptions.lastFrameImage = imageUrls[1];
            } else if (videoOptions.mode === "reference-images" && imageUrls.length > 0) {
              videoOptions.referenceImages = imageUrls;
            }

            chatApiLogger.info("[Chat API] Video options constructed:", {
              model: videoOptions.model,
              mode: videoOptions.mode,
              resolution: videoOptions.resolution,
              ratio: videoOptions.ratio,
              duration: videoOptions.duration,
              imageCount:
                videoOptions.referenceImages?.length ||
                Number(Boolean(videoOptions.firstFrameImage)) +
                  Number(Boolean(videoOptions.lastFrameImage)),
            });

            // 先写入占位消息，避免刷新后消息丢失
            const pendingText = "🎬 视频任务已创建，正在处理中，请稍候...";
            await saveMessages({
              messages: [
                {
                  id: videoMessageId,
                  chatId: id,
                  role: "assistant",
                  parts: [{ type: "text", text: pendingText }],
                  attachments: [],
                  createdAt: new Date(),
                  videoStorageStatus: "temporary",
                  temporaryVideoUrl: null,
                  permanentVideoUrl: null,
                  archivedAt: null,
                  videoMetadata: {
                    ...baseVideoMetadata,
                    model: actualVideoModelId,
                    status: "running",
                    updatedAt: Date.now(),
                  } as any,
                },
              ],
            });
            try {
              await persistVideoGenerationStartedTurn({
                userId: session.user.id,
                chatId: id,
                projectId: contextPayload?.projectId || null,
                messageId: videoMessageId,
                text: requestTextContent,
                source: "stream_video_provider",
                providerType: String(providerData.type || "stream"),
                modelRef: finalVideoModelData.id || finalModelId,
                mode: videoOptions.mode,
                status: "running",
              });
            } catch (videoWorkflowStartError) {
              chatApiLogger.warn("[Chat API] Failed to persist stream video start state:", videoWorkflowStartError);
            }

            dataStream.write({
              type: "data-appendMessage",
              data: JSON.stringify({
                id: videoMessageId,
                role: "assistant",
                parts: [{ type: "text", text: pendingText }],
                attachments: [],
              }),
            });

            const apiKey = providerData.apiKey;
            const baseURL = providerData.baseUrl || "https://ark.cn-beijing.volces.com/api/v3";
            chatApiLogger.info("[Chat API] Provider configured:", { baseURL, hasApiKey: !!apiKey });

            // 调用视频生成流
            chatApiLogger.info("[Chat API] Starting video generation stream...");
            const videoStream = doGenerateStream(apiKey, baseURL, videoOptions);

            // 收集所有流输出
            chatApiLogger.info("[Chat API] Processing video stream...");
            let fullText = "";
            let chunkCount = 0;

            for await (const chunk of videoStream) {
              chunkCount++;
              fullText += chunk;
              chatApiLogger.info(`[Chat API] Received chunk ${chunkCount}, length: ${chunk.length}`);
            }

            chatApiLogger.info(`[Chat API] Video stream completed. Total chunks: ${chunkCount}, total text length: ${fullText.length}`);

            // 提取流中的元数据并清理输出文案
            const metadataMatch = fullText.match(/<!--\s*VIDEO_METADATA:(.*?)-->/s);
            let streamMetadata: Record<string, any> = {};
            if (metadataMatch?.[1]) {
              try {
                streamMetadata = JSON.parse(metadataMatch[1]);
              } catch (parseError) {
                chatApiLogger.warn("[Chat API] Failed to parse VIDEO_METADATA from stream", parseError);
              }
            }
            const cleanedText = fullText
              .replace(/<!--\s*VIDEO_METADATA:.*?-->/gs, "")
              .trim();
            const videoUrlMatch = cleanedText.match(/<video[^>]+src="([^"]+)"/);
            const temporaryVideoUrl =
              (typeof streamMetadata.temporaryVideoUrl === "string" && streamMetadata.temporaryVideoUrl) ||
              (videoUrlMatch ? videoUrlMatch[1] : null);

            const successMetadata = {
              ...baseVideoMetadata,
              ...streamMetadata,
              model: actualVideoModelId,
              taskId:
                typeof streamMetadata.taskId === "string" && streamMetadata.taskId
                  ? streamMetadata.taskId
                  : undefined,
              status: "succeeded",
              completedAt: Date.now(),
              updatedAt: Date.now(),
            };

            await updateMessageById({
              messageId: videoMessageId,
              chatId: id,
              parts: [{ type: "text", text: cleanedText }],
              videoStorageStatus: temporaryVideoUrl ? "temporary" : null,
              temporaryVideoUrl: temporaryVideoUrl,
              permanentVideoUrl: null,
              archivedAt: null,
              videoMetadata: successMetadata as any,
            });
            try {
              await persistVideoGenerationCompletedTurn({
                userId: session.user.id,
                chatId: id,
                projectId: contextPayload?.projectId || null,
                messageId: videoMessageId,
                text: requestTextContent,
                source: "stream_video_provider",
                providerType: String(providerData.type || "stream"),
                modelRef: finalVideoModelData.id || finalModelId,
                mode: videoOptions.mode,
                taskId:
                  typeof successMetadata.taskId === "string" && successMetadata.taskId
                    ? successMetadata.taskId
                    : undefined,
                status: "completed",
                temporaryVideoUrl: temporaryVideoUrl || undefined,
              });
            } catch (videoWorkflowCompletedError) {
              chatApiLogger.warn("[Chat API] Failed to persist stream video completion state:", videoWorkflowCompletedError);
            }
            await consumeGeneratedVideoPoints({
              userId: session.user.id,
              chatId: id,
              messageId: videoMessageId,
              modelRefs: [finalVideoModelData.id, providerModelData.id, finalModelId],
              duration: Number(videoOptions.duration) || undefined,
              resolution: String(videoOptions.resolution || "").trim() || undefined,
            });

            dataStream.write({
              type: "data-appendMessage",
              data: JSON.stringify({
                id: videoMessageId,
                role: "assistant",
                parts: [{ type: "text", text: cleanedText }],
                attachments: [],
              }),
            });

            chatApiLogger.info("[Chat API] ✅ Video message updated successfully");
            if (temporaryVideoUrl) {
              chatApiLogger.info("[Chat API] 📹 临时视频URL已保存，开始异步归档到S3");
              scheduleVideoArchive({
                chatId: id,
                messageId: videoMessageId,
                text: cleanedText,
                temporaryVideoUrl,
                taskId:
                  typeof successMetadata.taskId === "string" && successMetadata.taskId
                    ? successMetadata.taskId
                    : videoMessageId,
                metadata: successMetadata,
              });
            }

            chatApiLogger.info("[Chat API] Video generation finished successfully");
            return;
          } catch (error: any) {
            chatApiLogger.error("[Chat API] ❌ Video generation error:", error);
            chatApiLogger.error("[Chat API] Error stack:", error.stack);

            const errorMessage = `❌ 视频生成失败：${error.message}\n\n请检查配置或稍后重试。`;
            const failedMetadata = {
              ...baseVideoMetadata,
              status: "failed",
              error: error?.message || "未知错误",
              updatedAt: Date.now(),
            };

            try {
              await updateMessageById({
                messageId: videoMessageId,
                chatId: id,
                parts: [{ type: "text", text: errorMessage }],
                videoStorageStatus: null,
                temporaryVideoUrl: null,
                permanentVideoUrl: null,
                archivedAt: null,
                videoMetadata: failedMetadata as any,
              });
              try {
                await persistVideoGenerationFailedTurn({
                  userId: session.user.id,
                  chatId: id,
                  projectId: contextPayload?.projectId || null,
                  messageId: videoMessageId,
                  text: requestTextContent,
                  source: "stream_video_provider",
                  providerType: "stream",
                  modelRef: finalModelId,
                  mode:
                    typeof effectiveVideoParams?.mode === "string"
                      ? effectiveVideoParams.mode
                      : undefined,
                  status: "failed",
                  error: error?.message || "未知错误",
                });
              } catch (videoWorkflowFailedError) {
                chatApiLogger.warn("[Chat API] Failed to persist stream video failure state:", videoWorkflowFailedError);
              }

              dataStream.write({
                type: "data-appendMessage",
                data: JSON.stringify({
                  id: videoMessageId,
                  role: "assistant",
                  parts: [{ type: "text", text: errorMessage }],
                  attachments: [],
                }),
              });
            } catch (updateError) {
              chatApiLogger.error("[Chat API] Failed to update placeholder video message:", updateError);
              const fallbackMessageId = generateUUID();
              dataStream.write({
                type: "data-appendMessage",
                data: JSON.stringify({
                  id: fallbackMessageId,
                  role: "assistant",
                  parts: [{ type: "text", text: errorMessage }],
                  attachments: [],
                }),
              });
              await saveMessages({
                messages: [
                  {
                    id: fallbackMessageId,
                    chatId: id,
                    role: "assistant",
                    parts: [{ type: "text", text: errorMessage }],
                    attachments: [],
                    createdAt: new Date(),
                    videoStorageStatus: null,
                    temporaryVideoUrl: null,
                    permanentVideoUrl: null,
                    archivedAt: null,
                    videoMetadata: failedMetadata as any,
                  },
                ],
              });
              try {
                await persistVideoGenerationFailedTurn({
                  userId: session.user.id,
                  chatId: id,
                  projectId: contextPayload?.projectId || null,
                  messageId: fallbackMessageId,
                  text: requestTextContent,
                  source: "stream_video_provider",
                  providerType: "stream",
                  modelRef: finalModelId,
                  mode:
                    typeof effectiveVideoParams?.mode === "string"
                      ? effectiveVideoParams.mode
                      : undefined,
                  status: "failed",
                  error: error?.message || "未知错误",
                });
              } catch (videoWorkflowFailedError) {
                chatApiLogger.warn("[Chat API] Failed to persist fallback stream video failure state:", videoWorkflowFailedError);
              }
            }

            return;
          }
        }

        // 常规文本模型使用 streamText
        const streamRequestTimeoutMs = resolvedModelSupportsImageGen ? 180_000 : 90_000;
        const shouldDisableSmoothStream =
          resolvedModelSupportsImageGen || isVolcanoVideoModel;

        const result = streamText({
          model: languageModel,
          system: effectiveConversationSystemPrompt,
          messages: convertedMessages,
          stopWhen: stepCountIs(5),
          experimental_activeTools:
            finalModelId === "chat-model-reasoning" || isVolcanoVideoModel ? [] : activeTools,
          experimental_transform: shouldDisableSmoothStream
            ? undefined
            : smoothStream({ chunking: "word" }),
          tools: isVolcanoVideoModel ? {} : tools, // 🆕 视频模型禁用工具
          abortSignal: AbortSignal.timeout(streamRequestTimeoutMs),
          experimental_telemetry: {
            isEnabled: isProductionEnvironment,
            functionId: "stream-text",
          },
          onFinish: async ({ usage }) => {
            if (activeRuntimeModelDescriptor?.providerKey) {
              recordProviderHealthSuccess({
                providerKey: activeRuntimeModelDescriptor.providerKey,
                providerType: activeRuntimeModelDescriptor.providerType,
              });
            }
            try {
              const providers = await getTokenlensCatalog();
              if (!actualModelId) {
                finalMergedUsage = usage;
                dataStream.write({
                  type: "data-usage",
                  data: finalMergedUsage,
                });
                return;
              }

              if (!providers) {
                finalMergedUsage = usage;
                dataStream.write({
                  type: "data-usage",
                  data: finalMergedUsage,
                });
                return;
              }

              const summary = getUsage({
                modelId: actualModelId,
                usage,
                providers,
              });
              finalMergedUsage = {
                ...usage,
                ...summary,
                modelId: actualModelId,
              } as AppUsage;
              dataStream.write({ type: "data-usage", data: finalMergedUsage });
            } catch (err) {
              chatApiLogger.warn("TokenLens enrichment failed", err);
              finalMergedUsage = usage;
              dataStream.write({ type: "data-usage", data: finalMergedUsage });
            }
          },
        });

          result.consumeStream({
            onError: (error) => {
              chatApiLogger.error("[Chat API] streamText consume error:", error);
              if (activeRuntimeModelDescriptor?.providerKey) {
                recordProviderHealthFailure({
                  providerKey: activeRuntimeModelDescriptor.providerKey,
                  providerType: activeRuntimeModelDescriptor.providerType,
                  error,
                });
              }
            },
          });

          dataStream.merge(
            result.toUIMessageStream({
              sendReasoning: true,
              onError: (error) => {
                chatApiLogger.error("[Chat API] streamText ui stream error:", error);
                if (activeRuntimeModelDescriptor?.providerKey) {
                  recordProviderHealthFailure({
                    providerKey: activeRuntimeModelDescriptor.providerKey,
                    providerType: activeRuntimeModelDescriptor.providerType,
                    error,
                  });
                }
                return getChatStreamErrorMessage(error);
              },
            })
          );
        } finally {
          setConversationStateProtocolEventObserver(null);
          stopStreamKeepalive = stopDefaultKeepalive;
        }
      },
      generateId: generateUUID,
      onFinish: async ({ messages }) => {
        stopStreamKeepalive?.();
        stopStreamKeepalive = null;
        const messagesToPersist: Array<{
          id: string;
          role: string;
          parts: unknown;
          createdAt: Date;
          attachments: unknown;
          chatId: string;
          videoStorageStatus: null;
          temporaryVideoUrl: null;
          permanentVideoUrl: null;
          archivedAt: null;
          videoMetadata: null;
        }> = [];

        for (const currentMessage of messages) {
          const normalizedParts =
            currentMessage.role === "assistant"
              ? normalizeAssistantPartsForPersistence(
                  currentMessage.parts as Array<Record<string, any>> | undefined,
                )
              : currentMessage.parts;

          if (
            currentMessage.role === "assistant" &&
            (!Array.isArray(normalizedParts) || normalizedParts.length === 0)
          ) {
            continue;
          }

          messagesToPersist.push({
            id: currentMessage.id,
            role: currentMessage.role,
            parts: normalizedParts,
            createdAt: new Date(),
            attachments: [],
            chatId: id,
            videoStorageStatus: null,
            temporaryVideoUrl: null,
            permanentVideoUrl: null,
            archivedAt: null,
            videoMetadata: null,
          });
        }

        if (messagesToPersist.length > 0) {
          await saveMessages({
            messages: messagesToPersist,
          });
        }

        // 检测助手消息中是否包含视频，如果有则立即标记并归档到永久存储
        for (const msg of messages) {
          if (msg.role === "assistant" && msg.parts) {
            const textContent = msg.parts
              .filter((part: any) => part && part.type === "text" && part.text)
              .map((part: any) => part.text)
              .join("");
            
            const tempVideoUrl = extractVideoUrlFromText(textContent);
            if (tempVideoUrl) {
              const genericVideoMetadata = {
                provider: "stream",
                model: actualModelId,
                status: "succeeded",
                updatedAt: Date.now(),
              };

              await updateMessageById({
                messageId: msg.id,
                chatId: id,
                videoStorageStatus: "temporary",
                temporaryVideoUrl: tempVideoUrl,
                permanentVideoUrl: null,
                archivedAt: null,
                videoMetadata: genericVideoMetadata as any,
              });
              try {
                await persistVideoGenerationCompletedTurn({
                  userId: session.user.id,
                  chatId: id,
                  projectId: contextPayload?.projectId || null,
                  messageId: msg.id,
                  text: requestTextContent,
                  source: "chat_stream_output",
                  providerType: "stream",
                  modelRef: actualModelId,
                  status: "completed",
                  temporaryVideoUrl: tempVideoUrl,
                });
              } catch (videoWorkflowCompletedError) {
                chatApiLogger.warn("[Chat API] Failed to persist streamed assistant video state:", videoWorkflowCompletedError);
              }

              scheduleVideoArchive({
                chatId: id,
                messageId: msg.id,
                text: textContent,
                temporaryVideoUrl: tempVideoUrl,
                taskId: msg.id,
                metadata: genericVideoMetadata,
              });
            }
          }
        }

        if (finalMergedUsage) {
          try {
            await updateChatLastContextById({
              chatId: id,
              context: finalMergedUsage,
            });
          } catch (err) {
            chatApiLogger.warn("Unable to persist last usage for chat", id, err);
          }
        }
      },
      onError: () => {
        stopStreamKeepalive?.();
        stopStreamKeepalive = null;
        return "Oops, an error occurred!";
      },
    });

    // const streamContext = getStreamContext();

    // if (streamContext) {
    //   return new Response(
    //     await streamContext.resumableStream(streamId, () =>
    //       stream.pipeThrough(new JsonToSseTransformStream())
    //     )
    //   );
    // }

    return createSseResponse(stream);
  } catch (error) {
    const vercelId = request.headers.get("x-vercel-id");

    if (error instanceof ChatSDKError) {
      return error.toResponse();
    }

    if (isRateLimitError(error)) {
      const detailMessage = getRequestErrorMessage(error);
      chatApiLogger.warn("[Chat API] Upstream rate limited request:", {
        vercelId,
        error: detailMessage,
      });
      return NextResponse.json(
        {
          code: "rate_limit:chat",
          message: getFriendlyRateLimitMessage(),
          cause: detailMessage || "upstream_rate_limited",
          retryAfter: 10,
        },
        {
          status: 429,
          headers: {
            "Retry-After": "10",
          },
        }
      );
    }

    // Check for Vercel AI Gateway credit card error
    if (
      error instanceof Error &&
      error.message?.includes(
        "AI Gateway requires a valid credit card on file to service requests"
      )
    ) {
      return new ChatSDKError("bad_request:activate_gateway").toResponse();
    }

    return createChatApiFailureResponse(error, vercelId);
  } finally {
    if (requestDedupKey && acquiredInFlightLock) {
      inFlightChatRequests.delete(requestDedupKey);
    }
  }
}

export async function DELETE(request: Request) {
  const { searchParams } = new URL(request.url);
  const id = searchParams.get("id");

  if (!id) {
    return new ChatSDKError("bad_request:api").toResponse();
  }

  const session = await auth();

  if (!session?.user) {
    return new ChatSDKError("unauthorized:chat").toResponse();
  }

  const chat = await getChatById({ id });

  if (chat?.userId !== session.user.id) {
    return new ChatSDKError("forbidden:chat").toResponse();
  }

  const deletedChat = await deleteChatById({ id });

  return Response.json(deletedChat, { status: 200 });
}