import "server-only";

import type { ConversationActionResolution } from "@/lib/ai/conversation-action-resolver";
import type { TaskBoundaryDecision } from "@/lib/ai/runtime/task-boundary-classifier";

export interface MemoryRelevancePolicy {
  includePromptMemory: boolean;
  includeImageWorkflowMemory: boolean;
  includeStoryboardPreferenceMemory: boolean;
  includeWorkflowState: boolean;
  maxMemoryHints: number;
  maxContextLines: number;
  reason: string;
}

export function resolveMemoryRelevancePolicy(params: {
  taskBoundaryDecision: TaskBoundaryDecision;
  actionResolution: ConversationActionResolution;
  hasActiveStoryboardTask: boolean;
  hasPendingGridConfirmation: boolean;
  hasCurrentImageInput: boolean;
  hasCanvasSelection: boolean;
}) {
  const { taskBoundaryDecision, actionResolution } = params;

  switch (taskBoundaryDecision.taskType) {
    case "greeting":
      return {
        includePromptMemory: false,
        includeImageWorkflowMemory: false,
        includeStoryboardPreferenceMemory: false,
        includeWorkflowState: false,
        maxMemoryHints: 0,
        maxContextLines: 2,
        reason: "greeting_turn_ignores_task_memory",
      } satisfies MemoryRelevancePolicy;
    case "chat":
      return {
        includePromptMemory: false,
        includeImageWorkflowMemory: false,
        includeStoryboardPreferenceMemory: false,
        includeWorkflowState: false,
        maxMemoryHints: 1,
        maxContextLines: 3,
        reason: "chat_turn_prefers_clean_context",
      } satisfies MemoryRelevancePolicy;
    case "prompt_only":
      return {
        includePromptMemory: false,
        includeImageWorkflowMemory: false,
        includeStoryboardPreferenceMemory: false,
        includeWorkflowState: false,
        maxMemoryHints: 2,
        maxContextLines: 4,
        reason: "prompt_only_turn_ignores_execution_memory",
      } satisfies MemoryRelevancePolicy;
    case "analysis_only":
      return {
        includePromptMemory: false,
        includeImageWorkflowMemory: false,
        includeStoryboardPreferenceMemory: false,
        includeWorkflowState: false,
        maxMemoryHints: 2,
        maxContextLines: 4,
        reason: "analysis_only_turn_ignores_workflow_memory",
      } satisfies MemoryRelevancePolicy;
    case "execution_video":
      return {
        includePromptMemory: false,
        includeImageWorkflowMemory: false,
        includeStoryboardPreferenceMemory: true,
        includeWorkflowState:
          params.hasActiveStoryboardTask || params.hasPendingGridConfirmation,
        maxMemoryHints: 4,
        maxContextLines: 6,
        reason: "video_execution_prefers_storyboard_preferences",
      } satisfies MemoryRelevancePolicy;
    case "workflow_followup":
      return {
        includePromptMemory:
          actionResolution.kind === "image_generation_followup" ||
          actionResolution.kind === "prompt_carry_forward",
        includeImageWorkflowMemory:
          actionResolution.kind === "image_edit_followup" ||
          actionResolution.kind === "image_generation_followup" ||
          actionResolution.kind === "prompt_carry_forward",
        includeStoryboardPreferenceMemory:
          actionResolution.kind === "grid_confirmation_followup" ||
          actionResolution.kind === "active_storyboard_followup",
        includeWorkflowState: true,
        maxMemoryHints: 6,
        maxContextLines: 8,
        reason: "workflow_followup_requires_workflow_memory",
      } satisfies MemoryRelevancePolicy;
    case "execution_image":
    default:
      return {
        includePromptMemory:
          actionResolution.usePromptCarryForward ||
          taskBoundaryDecision.taskMode === "continue",
        includeImageWorkflowMemory:
          taskBoundaryDecision.taskMode === "continue" ||
          (!params.hasCurrentImageInput && !params.hasCanvasSelection),
        includeStoryboardPreferenceMemory: false,
        includeWorkflowState:
          taskBoundaryDecision.taskMode === "continue" &&
          (actionResolution.kind === "image_edit_followup" ||
            actionResolution.kind === "image_generation_followup" ||
            actionResolution.kind === "prompt_carry_forward"),
        maxMemoryHints: taskBoundaryDecision.taskMode === "continue" ? 5 : 3,
        maxContextLines: taskBoundaryDecision.taskMode === "continue" ? 7 : 5,
        reason:
          taskBoundaryDecision.taskMode === "continue"
            ? "image_execution_continue_reuses_relevant_memory"
            : "image_execution_new_task_limits_old_memory",
      } satisfies MemoryRelevancePolicy;
  }
}

export function applyMemoryHintLimit(hints: string[], maxHints: number) {
  if (!Array.isArray(hints) || maxHints <= 0) return [] as string[];
  return hints.slice(0, maxHints);
}

export function applyContextLineLimit(summary: string | undefined, maxLines: number) {
  const normalized = String(summary || "").trim();
  if (!normalized || maxLines <= 0) return "";
  return normalized
    .split("\n")
    .map((line) => line.trim())
    .filter(Boolean)
    .slice(0, maxLines)
    .join("\n");
}