import "server-only";

import type { AgentThreadState } from "@/lib/ai/runtime/agent-thread-state";
import type { PromptMemoryEntry } from "@/lib/ai/prompt-memory";
import type { ImageWorkflowMemory } from "@/lib/ai/image-workflow-memory";
import type { StoryboardPreferenceMemory } from "@/lib/video-agent/storyboard-preference-memory";
import { buildAgentThreadStateFromStoryboardTask } from "@/lib/video-agent/agent-thread-state";

type StoryboardTaskDetail = Parameters<typeof buildAgentThreadStateFromStoryboardTask>[0];

function normalizeText(value: unknown, max = 240): string | undefined {
  const normalized = String(value || "").trim();
  if (!normalized) return undefined;
  return normalized.slice(0, max);
}

export function buildConversationThreadState(params: {
  activeStoryboardTask?: StoryboardTaskDetail | null;
  storyboardPreferenceMemory?: StoryboardPreferenceMemory | null;
  promptMemory?: PromptMemoryEntry | null;
  imageWorkflowMemory?: ImageWorkflowMemory | null;
}): AgentThreadState | null {
  const storyboardState = buildAgentThreadStateFromStoryboardTask(
    params.activeStoryboardTask,
    {
      storyboardPreferenceMemory: params.storyboardPreferenceMemory,
      promptMemory: params.promptMemory,
    },
  );

  if (params.activeStoryboardTask?.task?.id) {
    return {
      workflowState: storyboardState?.workflowState || null,
      memoryHints: [
        ...(storyboardState?.memoryHints || []),
        params.imageWorkflowMemory?.lastOptimizedPrompt
          ? "当前会话里也保留了最近一次图片工作流记忆，可辅助理解用户是在继续哪一轮生图。"
          : "",
      ].filter(Boolean),
      contextSummary:
        storyboardState?.contextSummary ||
        normalizeText(params.imageWorkflowMemory?.lastUserPrompt, 320),
      metadata: {
        ...(storyboardState?.metadata || {}),
        imageWorkflowMemory: params.imageWorkflowMemory || undefined,
      },
    };
  }

  const hasImageFollowup =
    Boolean(params.promptMemory?.optimizedPrompt) ||
    Boolean(params.imageWorkflowMemory?.lastOptimizedPrompt) ||
    Boolean(params.imageWorkflowMemory?.lastResultImageUrls?.length) ||
    Boolean(params.imageWorkflowMemory?.lastSourceImageUrls?.length);

  if (!hasImageFollowup && !params.storyboardPreferenceMemory) {
    return null;
  }

  const preferredCount = params.imageWorkflowMemory?.lastRequestedImageCount;
  const preferredRatio = params.imageWorkflowMemory?.lastAspectRatio;
  const preferredSize = params.imageWorkflowMemory?.lastImageSize;
  const sourceCount = params.imageWorkflowMemory?.lastSourceImageUrls?.length || 0;
  const resultCount = params.imageWorkflowMemory?.lastResultImageUrls?.length || 0;
  const imageFollowupType =
    params.imageWorkflowMemory?.lastIntent === "image_edit"
      ? "image_edit_followup"
      : "image_generation_followup";
  const imageFollowupTitle =
    imageFollowupType === "image_edit_followup"
      ? "连续修图工作流"
      : "连续生图工作流";

  return {
    workflowState: hasImageFollowup
      ? {
          workflowId: "image-generation-followup",
          type: imageFollowupType,
          status: "draft",
          title: imageFollowupTitle,
          summary: [
            params.promptMemory?.optimizedPrompt || params.imageWorkflowMemory?.lastOptimizedPrompt
              ? "当前会话中存在上一轮可复用提示词。"
              : "",
            preferredCount ? `上一轮目标出图数：${preferredCount} 张。` : "",
            preferredRatio ? `上一轮画幅：${preferredRatio}。` : "",
            preferredSize ? `上一轮清晰度：${preferredSize}。` : "",
            sourceCount > 0 ? `上一轮参考图数：${sourceCount}。` : "",
            resultCount > 0 ? `上一轮结果图数：${resultCount}。` : "",
          ]
            .filter(Boolean)
            .join(" "),
          confirmPhrases: ["按上一个提示词生成", "继续生成", "就按这个来"],
          revisionHints: ["换一版", "保持提示词不变再来一组", "沿用上一个提示词"],
          pendingItems: [],
          metadata: {
            promptMemory: params.promptMemory || undefined,
            imageWorkflowMemory: params.imageWorkflowMemory || undefined,
            storyboardPreferenceMemory: params.storyboardPreferenceMemory || undefined,
          },
        }
      : null,
    memoryHints: [
      params.promptMemory?.optimizedPrompt
        ? "当前会话存在上一轮可复用提示词；如果用户明确要求沿用它继续生成，应优先复用。"
        : "",
      params.imageWorkflowMemory?.lastResultImageUrls?.length
        ? "当前会话保留了上一轮生成结果图，可用于理解“继续做这张/沿用上一版”的指代。"
        : "",
      params.imageWorkflowMemory?.lastSourceImageUrls?.length
        ? "当前会话保留了上一轮参考图/目标图，可用于连续图生图理解。"
        : "",
      params.storyboardPreferenceMemory
        ? "当前会话也存在 storyboard 偏好记忆，后续如果转入分镜任务可继续复用。"
        : "",
    ].filter(Boolean),
    contextSummary: [
      params.promptMemory?.optimizedPrompt
        ? `上一轮提示词摘要：${normalizeText(params.promptMemory.optimizedPrompt, 180)}`
        : "",
      params.imageWorkflowMemory?.lastUserPrompt
        ? `上一轮用户原始需求：${normalizeText(params.imageWorkflowMemory.lastUserPrompt, 180)}`
        : "",
    ]
      .filter(Boolean)
      .join("\n"),
    metadata: {
      promptMemory: params.promptMemory || undefined,
      imageWorkflowMemory: params.imageWorkflowMemory || undefined,
      storyboardPreferenceMemory: params.storyboardPreferenceMemory || undefined,
    },
  };
}