'use client';
// 屏4 挑图：0/N异步电影 + 按A/B/C分组选图 + 点图放大 + 单批重试 + 能离开
import { useState } from 'react';
import { useRouter, useParams } from 'next/navigation';
import { ProgressBar } from '@/components/layout/ProgressBar';
import { FlywheelBannerFromSse } from '@/components/FlywheelBanner';
import { ImageProgressCardSkeleton } from '@/components/tasks/ImageProgressCard';
import { ImageProgressHeader } from '@/components/tasks/ImageProgressHeader';
import { ImageActionBar } from '@/components/tasks/ImageActionBar';
import { ImageLightbox } from '@/components/tasks/ImageLightbox';
import { ImageStrategyGroup, ROLE_LABEL } from '@/components/tasks/ImageStrategyGroup';
import { RegenControls, RegenTarget } from '@/components/tasks/RegenControls';
import { SseStatusBar } from '@/components/tasks/SseStatusBar';
import { FatalErrorBanner } from '@/components/tasks/FatalErrorBanner';
import { RejectReasonBanner } from '@/components/tasks/RejectReasonBanner';
import { useSse } from '@/hooks/useSse';
import { useGenerationStore } from '@/stores/generationStore';
import { useTaskStore } from '@/stores/taskStore';
import { ImageCandidate } from '@/types/index';
import { api } from '@/lib/api';

export default function ImageSelectionPage() {
  const params = useParams<{ id: string }>();
  const taskId = params?.id ? Number(params.id) : null;
  const router = useRouter();

  const { imageCandidates, imageDone, imageTotal, failedBatches, flywheelInjected } = useGenerationStore();
  const { selectedImageIds, toggleImageSelection } = useTaskStore();
  const { connectionStatus, reconnectAttempt } = useSse(taskId);
  const [zoom, setZoom] = useState<ImageCandidate | null>(null);
  const [regenTarget, setRegenTarget] = useState<RegenTarget | null>(null);

  const pendingCount = imageTotal - imageDone;
  const allDone = imageTotal > 0 && pendingCount === 0;

  // 按套(A/B/C)分组展示；R2 同套同角色去重，只留最新一张（candidate_id 最大=最新重生）
  function latestByRole(list: ImageCandidate[]): ImageCandidate[] {
    const byRole = new Map<string, ImageCandidate>();
    for (const c of list) {
      const prev = byRole.get(c.role);
      if (!prev || c.candidate_id > prev.candidate_id) byRole.set(c.role, c);
    }
    return Array.from(byRole.values());
  }
  const groups: Array<['A' | 'B' | 'C', ImageCandidate[]]> = (['A', 'B', 'C'] as const).map(
    (s) => [s, latestByRole(imageCandidates.filter((c) => c.strategy === s))]
  );

  async function handleRetry(_batchRole: string) {
    // 一期 regenerate = 整体重生（R2 已扩展按角色单批重生，见 handleRegen）
    if (!taskId) return;
    await api.post(`/api/v1/tasks/${taskId}/regenerate`);
  }

  // R2 单张/单套重生 + 可选人工提示词
  async function handleRegen(target: RegenTarget, customPrompt: string) {
    if (!taskId) return;
    await api.post(`/api/v1/tasks/${taskId}/regenerate`, {
      strategy: target.strategy,
      role: target.role,
      custom_prompt: customPrompt || undefined,
    });
  }

  function openRegen(strategy: string, role: string | undefined, label: string) {
    setRegenTarget({ strategy: strategy as 'A' | 'B' | 'C', role, label });
  }

  async function handleProceedToConfirm() {
    if (!taskId || selectedImageIds.length === 0) return;
    for (const candidateId of selectedImageIds) {
      await api.post(`/api/v1/tasks/${taskId}/image-candidates/select`, { candidate_id: candidateId });
    }
    router.push(`/tasks/${taskId}/confirm`);
  }

  return (
    <div className="flex flex-col h-full">
      <ProgressBar currentStep={3} />
      <RejectReasonBanner taskId={taskId} />
      {flywheelInjected && (
        <FlywheelBannerFromSse
          recentPreference={flywheelInjected.recentPreference}
          rejectReasons={flywheelInjected.rejectReasons}
        />
      )}
      <SseStatusBar status={connectionStatus} attempt={reconnectAttempt} />
      <div className="p-6 flex-1 overflow-auto">
        <FatalErrorBanner />
        <ImageProgressHeader imageTotal={imageTotal} imageDone={imageDone} pendingCount={pendingCount} />
        {imageCandidates.length === 0 ? (
          <div className="grid grid-cols-3 gap-3 xl:grid-cols-6">
            {Array.from({ length: 6 }).map((_, i) => <ImageProgressCardSkeleton key={i} />)}
          </div>
        ) : (
          groups.map(([s, list]) =>
            list.length > 0 ? (
              <ImageStrategyGroup
                key={s}
                strategy={s}
                candidates={list}
                selectedImageIds={selectedImageIds}
                onToggle={toggleImageSelection}
                onZoom={setZoom}
                onRegen={openRegen}
              />
            ) : null
          )
        )}
        {/* 失败批次提示 */}
        {failedBatches.length > 0 && allDone && (
          <div role="alert" className="mt-4 bg-red-50 border border-status-error rounded-xl px-4 py-3 text-sm text-status-error">
            有 {failedBatches.length} 批没出来。
            {failedBatches.filter((b) => b.retryable).map((b) => (
              <button key={b.batch} onClick={() => handleRetry(b.batch)}
                className="ml-2 underline" aria-label={`重试${ROLE_LABEL[b.batch] || b.batch}`}>
                ⟳ 重试{ROLE_LABEL[b.batch] || b.batch}
              </button>
            ))}
          </div>
        )}
        {imageCandidates.length > 0 && (
          <ImageActionBar selectedCount={selectedImageIds.length} onProceed={handleProceedToConfirm} />
        )}
      </div>
      <ImageLightbox
        url={zoom?.url ?? null}
        caption={zoom ? (ROLE_LABEL[zoom.role] || zoom.role) : undefined}
        onClose={() => setZoom(null)}
      />
      <RegenControls
        target={regenTarget}
        onClose={() => setRegenTarget(null)}
        onSubmit={handleRegen}
      />
    </div>
  );
}