const express = require('express');
const { exec, spawn } = require('child_process');
const path = require('path');
const fs = require('fs');
const cors = require('cors');
const crypto = require('crypto');
const multer = require('multer');
const { Readable, Transform } = require('stream');
const { pipeline } = require('stream/promises');

const LOCAL_ENV_PATH = path.join(__dirname, '.env');
if (fs.existsSync(LOCAL_ENV_PATH)) {
  const envText = fs.readFileSync(LOCAL_ENV_PATH, 'utf-8');
  for (const rawLine of envText.split(/\r?\n/)) {
    const line = rawLine.trim();
    if (!line || line.startsWith('#')) {
      continue;
    }

    const separatorIndex = line.indexOf('=');
    if (separatorIndex <= 0) {
      continue;
    }

    const key = line.slice(0, separatorIndex).trim();
    let value = line.slice(separatorIndex + 1).trim();
    if ((value.startsWith('"') && value.endsWith('"')) || (value.startsWith("'") && value.endsWith("'"))) {
      value = value.slice(1, -1);
    }

    if (key && process.env[key] === undefined) {
      process.env[key] = value;
    }
  }
}

const app = express();
const PORT = 3000;
const PROJECT_ROOT = __dirname;
const DATA_DIR = path.join(PROJECT_ROOT, 'data');
const DATA_VIDEO_DIR = path.join(DATA_DIR, 'videos');
const DATA_REMIX_ASSET_DIR = path.join(DATA_DIR, 'remix-assets');
const LEGACY_VIDEO_DIR = path.join(PROJECT_ROOT, 'src', 'video');
const VOICE_SPEAKER_ID_DOC_PATH = path.join(PROJECT_ROOT, 'docs', '音色创建', 'speaker_id.md');
const MANIFEST_PATH = path.join(DATA_DIR, 'manifest.json');
const LEGACY_MANIFEST_PATH = path.join(LEGACY_VIDEO_DIR, 'manifest.json');
const WHISPER_DIR = path.join(PROJECT_ROOT, 'Whisper');
const downloadTasks = new Map();
const QINIU_ACCESS_KEY = process.env.QINIU_AK || 'EXsA-z_n4LGmWrwC088bygcGJtAditnWQe2nH-ZE';
const QINIU_SECRET_KEY = process.env.QINIU_SK || 'HWTL92OL-Tup0-8ex8A9jnG3OaJzTxlF4OwiiDsX';
const QINIU_BUCKET = 'nova-repos';
const QINIU_CDN_DOMAIN = 'https://repos.fmode.cn';
const QINIU_CDN_PREFIX = 'x/openclaw-skills';
const QINIU_UPLOAD_URL = 'https://up-z2.qiniup.com';
const VOLC_SPEECH_BASE_URL = 'https://openspeech.bytedance.com';
const VOLC_TTS_PROXY_BASE_URL = process.env.VOLC_TTS_PROXY_BASE_URL || 'https://server.fmode.cn/api/volcengine/tts';
const VOLC_SPEECH_API_KEY = process.env.VOLC_SPEECH_API_KEY || process.env.BYTEDANCE_SPEECH_API_KEY || process.env.VOICE_CREATION_API_KEY || 'f112a70a-4754-4d73-8a14-a05f9b57bf65';
const VOLC_TTS_RESOURCE_ID = process.env.VOLC_TTS_RESOURCE_ID || '';
const VOLC_SPEECH_APP_KEY = process.env.VOLC_SPEECH_APP_KEY || process.env.VOLC_SPEECH_APP_ID || '';
const VOLC_SPEECH_ACCESS_KEY = process.env.VOLC_SPEECH_ACCESS_KEY || '';

app.use(cors());
app.use(express.json({ limit: '50mb' }));

// 静态文件：提供视频文件的访问
const staticVideoOptions = {
  setHeaders: (res, filePath) => {
    if (filePath.match(/\.(mp4|mov|webm|mkv|avi)$/i)) {
      res.setHeader('Content-Type', 'video/mp4');
      res.setHeader('Accept-Ranges', 'bytes');
    }
  }
};
app.use('/api/video', express.static(DATA_VIDEO_DIR, staticVideoOptions));
app.use('/api/video', express.static(LEGACY_VIDEO_DIR, staticVideoOptions));

// ==================== 文件上传配置 ====================

const uploadStorage = multer.diskStorage({
  destination: (req, file, cb) => {
    const uploadDir = DATA_VIDEO_DIR;
    if (!fs.existsSync(uploadDir)) fs.mkdirSync(uploadDir, { recursive: true });
    cb(null, uploadDir);
  },
  filename: (req, file, cb) => {
    // 保留原始文件名，如有冲突则加时间戳
    const originalName = Buffer.from(file.originalname, 'latin1').toString('utf8');
    const ext = path.extname(originalName);
    const baseName = path.basename(originalName, ext);
    const targetPath = path.join(DATA_VIDEO_DIR, originalName);
    if (fs.existsSync(targetPath)) {
      cb(null, `${baseName}-${Date.now()}${ext}`);
    } else {
      cb(null, originalName);
    }
  }
});

const assetUpload = multer({
  storage: multer.memoryStorage(),
  // 200MB 以支持动作迁移 / 素材拼接场景的参考视频上传
  limits: { fileSize: 200 * 1024 * 1024 }
});

const upload = multer({
  storage: uploadStorage,
  limits: { fileSize: 500 * 1024 * 1024 }, // 500MB
  fileFilter: (req, file, cb) => {
    const allowedTypes = ['video/mp4', 'video/quicktime', 'video/x-msvideo', 'video/webm', 'video/x-matroska'];
    if (allowedTypes.includes(file.mimetype) || file.originalname.match(/\.(mp4|mov|avi|webm|mkv)$/i)) {
      cb(null, true);
    } else {
      cb(new Error('仅支持视频文件（mp4, mov, avi, webm, mkv）'));
    }
  }
});

// ==================== 工具函数 ====================

// 确保 data 目录存在
if (!fs.existsSync(DATA_DIR)) fs.mkdirSync(DATA_DIR, { recursive: true });
if (!fs.existsSync(DATA_VIDEO_DIR)) fs.mkdirSync(DATA_VIDEO_DIR, { recursive: true });
if (!fs.existsSync(DATA_REMIX_ASSET_DIR)) fs.mkdirSync(DATA_REMIX_ASSET_DIR, { recursive: true });

function ensureManifestFile() {
  if (fs.existsSync(MANIFEST_PATH)) return;
  if (fs.existsSync(LEGACY_MANIFEST_PATH)) {
    fs.copyFileSync(LEGACY_MANIFEST_PATH, MANIFEST_PATH);
    return;
  }
  fs.writeFileSync(MANIFEST_PATH, '[]', 'utf-8');
}

function readManifest() {
  ensureManifestFile();
  const raw = fs.readFileSync(MANIFEST_PATH, 'utf-8');
  return JSON.parse(raw);
}

function writeManifest(data) {
  ensureManifestFile();
  fs.writeFileSync(MANIFEST_PATH, JSON.stringify(data, null, 2), 'utf-8');
}

function resolveVideoPath(filename) {
  const runtimePath = path.join(DATA_VIDEO_DIR, filename);
  if (fs.existsSync(runtimePath)) return runtimePath;

  const legacyPath = path.join(LEGACY_VIDEO_DIR, filename);
  if (fs.existsSync(legacyPath)) return legacyPath;

  return runtimePath;
}

function removeFileIfExists(filePath) {
  try {
    if (filePath && fs.existsSync(filePath)) {
      fs.unlinkSync(filePath);
    }
  } catch (err) {
    // 忽略竞态条件 / 权限问题导致的删除失败，避免 ENOENT 等异常中断主流程
    if (err && err.code !== 'ENOENT') {
      console.warn(`⚠️ 删除文件失败 ${filePath}: ${err.message}`);
    }
  }
}

function removeDirectoryIfExists(dirPath) {
  if (fs.existsSync(dirPath)) {
    fs.rmSync(dirPath, { recursive: true, force: true });
  }
}

function toBase64Url(input) {
  return Buffer.from(input)
    .toString('base64')
    .replace(/\+/g, '-')
    .replace(/\//g, '_');
}

function buildQiniuUploadToken(key) {
  const deadline = Math.floor(Date.now() / 1000) + 3600;
  const putPolicy = {
    scope: `${QINIU_BUCKET}:${key}`,
    deadline
  };
  const encodedPutPolicy = toBase64Url(JSON.stringify(putPolicy));
  const sign = crypto
    .createHmac('sha1', QINIU_SECRET_KEY)
    .update(encodedPutPolicy)
    .digest('base64')
    .replace(/\+/g, '-')
    .replace(/\//g, '_');

  return `${QINIU_ACCESS_KEY}:${sign}:${encodedPutPolicy}`;
}

function buildDigitalHumanAssetKey(fileName, kind) {
  const rawName = Buffer.from(fileName || `asset-${Date.now()}`, 'latin1').toString('utf8');
  const ext = path.extname(rawName).toLowerCase();
  const safeExt = ext && /^[.a-z0-9]+$/i.test(ext) ? ext : '';
  const baseName = path.basename(rawName, ext).replace(/[^a-zA-Z0-9_-]/g, '_') || `asset-${Date.now()}`;
  const date = new Date();
  const yyyy = date.getFullYear();
  const mm = String(date.getMonth() + 1).padStart(2, '0');
  const dd = String(date.getDate()).padStart(2, '0');
  const timestamp = `${yyyy}${mm}${dd}-${Date.now()}`;
  return `${QINIU_CDN_PREFIX}/digital-human/${kind}/${yyyy}${mm}${dd}/${timestamp}-${baseName}${safeExt}`;
}

function createRequestId() {
  return typeof crypto.randomUUID === 'function'
    ? crypto.randomUUID()
    : `${Date.now()}-${crypto.randomBytes(8).toString('hex')}`;
}

function buildSpeechHeaders(contentType = 'application/json') {
  const headers = {
    'Content-Type': contentType,
    'X-Api-Request-Id': createRequestId()
  };

  if (VOLC_SPEECH_API_KEY) {
    headers['X-Api-Key'] = VOLC_SPEECH_API_KEY;
    return headers;
  }

  if (VOLC_SPEECH_APP_KEY && VOLC_SPEECH_ACCESS_KEY) {
    headers['X-Api-App-Key'] = VOLC_SPEECH_APP_KEY;
    headers['X-Api-Access-Key'] = VOLC_SPEECH_ACCESS_KEY;
    return headers;
  }

  throw new Error('未配置火山语音鉴权，请设置 VOLC_SPEECH_API_KEY 或 VOLC_SPEECH_APP_KEY + VOLC_SPEECH_ACCESS_KEY');
}

function normalizeOfficialSpeechResourceId(value) {
  const resourceId = String(value || '').trim();
  return /^seed-(tts|icl)-/i.test(resourceId) ? resourceId : '';
}

function inferOfficialSpeechResourceId(speaker, requestedResourceId = '') {
  const explicitResourceId = normalizeOfficialSpeechResourceId(requestedResourceId);
  if (explicitResourceId) {
    return explicitResourceId;
  }

  const configuredResourceId = normalizeOfficialSpeechResourceId(VOLC_TTS_RESOURCE_ID);
  if (configuredResourceId) {
    return configuredResourceId;
  }

  const normalizedSpeaker = String(speaker || '').trim();
  if (/^(S_|icl_|saturn_|dit_)/i.test(normalizedSpeaker)) {
    return 'seed-icl-2.0';
  }

  return 'seed-tts-2.0';
}

function clampNumber(value, fallback, min, max) {
  const numericValue = Number(value);
  if (!Number.isFinite(numericValue)) {
    return fallback;
  }

  return Math.min(max, Math.max(min, numericValue));
}

function clampOptionalNumber(value, min, max) {
  if (value === null || value === undefined || String(value).trim() === '') {
    return null;
  }

  const numericValue = Number(value);
  if (!Number.isFinite(numericValue)) {
    return null;
  }

  return Math.min(max, Math.max(min, numericValue));
}

function parseOptionalBoolean(value, fallback = false) {
  if (value === null || value === undefined || value === '') {
    return fallback;
  }

  if (typeof value === 'boolean') {
    return value;
  }

  if (typeof value === 'number') {
    return value !== 0;
  }

  const normalizedValue = String(value).trim().toLowerCase();
  if (['true', '1', 'yes', 'on'].includes(normalizedValue)) {
    return true;
  }

  if (['false', '0', 'no', 'off'].includes(normalizedValue)) {
    return false;
  }

  return fallback;
}

function normalizeVoiceSynthesisErrorMessage(message) {
  const rawMessage = String(message || '').trim();
  if (/resource ID is mismatched with speaker related resource/i.test(rawMessage)) {
    return '当前本地 X-Api-Key 与所选 speaker_id 不属于同一语音资源，无法直接使用 speaker_id 合成。请先通过音色复刻获取 timbreId 后再合成，或更换与该 speaker_id 匹配的 X-Api-Key。';
  }

  return rawMessage || '语音合成失败';
}

function mapVoiceDesignStatus(status) {
  switch (Number(status)) {
    case 0:
      return '未找到';
    case 1:
      return '训练中';
    case 2:
      return '可用';
    case 3:
      return '失败';
    case 4:
      return '已激活';
    default:
      return '未知';
  }
}

function mapVoiceCloneStatus(status) {
  switch (String(status ?? '')) {
    case '0':
      return '未占用';
    case '1':
      return '可用';
    case '2':
      return '训练中';
    case '3':
      return '失败';
    case '404':
      return '已删除';
    default:
      return '未知';
  }
}

function normalizeBearerToken(token) {
  const rawToken = String(token || '').trim();
  if (!rawToken) {
    return '';
  }

  return /^Bearer\s+/i.test(rawToken) ? rawToken : `Bearer ${rawToken}`;
}

function inferAudioFormat(file) {
  const mimeType = String(file?.mimetype || '').toLowerCase();
  if (mimeType.includes('mpeg') || mimeType.includes('mp3')) {
    return 'mp3';
  }
  if (mimeType.includes('wav')) {
    return 'wav';
  }
  if (mimeType.includes('m4a') || mimeType.includes('mp4')) {
    return 'm4a';
  }
  if (mimeType.includes('aac')) {
    return 'aac';
  }
  if (mimeType.includes('flac')) {
    return 'flac';
  }
  if (mimeType.includes('ogg') || mimeType.includes('opus')) {
    return 'ogg_opus';
  }
  if (mimeType.includes('pcm')) {
    return 'pcm';
  }

  const ext = path.extname(file?.originalname || '').toLowerCase();
  switch (ext) {
    case '.wav':
      return 'wav';
    case '.m4a':
      return 'm4a';
    case '.aac':
      return 'aac';
    case '.flac':
      return 'flac';
    case '.ogg':
    case '.opus':
      return 'ogg_opus';
    case '.pcm':
      return 'pcm';
    case '.mp3':
    default:
      return 'mp3';
  }
}

async function readFetchResponse(response) {
  const rawText = await response.text();
  let payload = null;
  try {
    payload = rawText ? JSON.parse(rawText) : null;
  } catch {
    payload = null;
  }

  return {
    rawText,
    payload
  };
}

function extractPrimaryVoiceModel(timbre) {
  if (!Array.isArray(timbre?.models) || timbre.models.length === 0) {
    return {};
  }

  return timbre.models[0] || {};
}

function readVoiceSpeakerIdOptions() {
  if (!fs.existsSync(VOICE_SPEAKER_ID_DOC_PATH)) {
    return [];
  }

  const rawText = fs.readFileSync(VOICE_SPEAKER_ID_DOC_PATH, 'utf-8');
  const seen = new Set();
  const options = [];

  for (const rawLine of rawText.split(/\r?\n/)) {
    const speakerId = rawLine.trim().match(/^S_[A-Za-z0-9]+$/)?.[0] || '';
    if (!speakerId || seen.has(speakerId)) {
      continue;
    }
    seen.add(speakerId);
    options.push(speakerId);
  }

  return options;
}

function upsertVoiceProfile(profile) {
  const profiles = readDataFile('voice-profiles');
  const existingIndex = profiles.findIndex((item) => (
    (!!profile.timbre_id && item.timbre_id === profile.timbre_id)
    || (!!profile.id && item.id === profile.id)
  ));

  if (existingIndex >= 0) {
    const existingProfile = profiles[existingIndex];
    const nextProfile = {
      ...existingProfile,
      ...profile,
      id: existingProfile.id || profile.id,
      created_at: existingProfile.created_at || profile.created_at,
      updated_at: profile.updated_at || new Date().toISOString()
    };
    profiles[existingIndex] = nextProfile;
    writeDataFile('voice-profiles', profiles);
    return nextProfile;
  }

  profiles.unshift(profile);
  writeDataFile('voice-profiles', profiles);
  return profile;
}

async function requestVolcTtsJson(endpoint, requestBody) {
  const response = await fetch(`${VOLC_TTS_PROXY_BASE_URL}/${endpoint}`, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    },
    body: JSON.stringify(requestBody)
  });

  const { rawText, payload } = await readFetchResponse(response);
  if (!response.ok) {
    const error = new Error(payload?.error?.message || payload?.message || payload?.error || rawText || 'TTS 请求失败');
    error.status = response.status;
    error.detail = payload || rawText || '';
    throw error;
  }

  return payload;
}

async function proxyVolcTtsStream(endpoint, requestBody, res) {
  const response = await fetch(`${VOLC_TTS_PROXY_BASE_URL}/${endpoint}`, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    },
    body: JSON.stringify(requestBody)
  });

  if (!response.ok) {
    const { rawText, payload } = await readFetchResponse(response);
    const error = new Error(payload?.error?.message || payload?.message || payload?.error || rawText || 'TTS 流式请求失败');
    error.status = response.status;
    error.detail = payload || rawText || '';
    throw error;
  }

  res.status(response.status);
  res.setHeader('Content-Type', response.headers.get('content-type') || 'application/x-ndjson; charset=utf-8');
  res.setHeader('Cache-Control', 'no-cache, no-transform');

  if (!response.body) {
    res.end();
    return;
  }

  await pipeline(Readable.fromWeb(response.body), res);
}

async function synthesizeVoiceAudio({ token, speaker, timbreId, text, ssml, xApiResourceId, model, isStream = false, audioParams = {}, additions = {} }) {
  const normalizedSpeaker = String(speaker || '').trim();
  const fallbackSpeaker = String(timbreId || '').trim();
  const resolvedSpeaker = normalizedSpeaker || fallbackSpeaker;
  const requestedResourceId = String(xApiResourceId || '').trim();
  const headerResourceId = inferOfficialSpeechResourceId(resolvedSpeaker, requestedResourceId);
  const resolvedModel = String(model || '').trim();
  const serializedAdditions = Object.keys(additions).length > 0 ? JSON.stringify(additions) : '';
  const requestBody = {
    req_params: {
      ...(ssml ? { ssml } : { text }),
      speaker: resolvedSpeaker,
      audio_params: {
        format: audioParams.format || 'mp3',
        sample_rate: audioParams.sampleRate ?? 24000,
        ...(audioParams.speechRate === null || audioParams.speechRate === undefined ? {} : { speech_rate: audioParams.speechRate }),
        ...(audioParams.loudnessRate === null || audioParams.loudnessRate === undefined ? {} : { loudness_rate: audioParams.loudnessRate }),
        ...(audioParams.emotion ? { emotion: audioParams.emotion } : {}),
        ...(audioParams.emotionScale === null || audioParams.emotionScale === undefined ? {} : { emotion_scale: audioParams.emotionScale }),
        ...(audioParams.enableSubtitle ? { enable_subtitle: true } : {})
      },
      ...(serializedAdditions ? { additions: serializedAdditions } : {}),
      ...(resolvedModel ? { model: resolvedModel } : {})
    }
  };

  const headers = buildSpeechHeaders();
  headers['X-Api-Resource-Id'] = headerResourceId;
  headers['Connection'] = 'keep-alive';

  const response = await fetch(`${VOLC_SPEECH_BASE_URL}/api/v3/tts/unidirectional`, {
    method: 'POST',
    headers,
    body: JSON.stringify(requestBody)
  });

  const { rawText, payload } = await readFetchResponse(response);
  if (!response.ok) {
    const error = new Error(normalizeVoiceSynthesisErrorMessage(payload?.error?.message || payload?.message || payload?.error || rawText || 'TTS 请求失败'));
    error.status = response.status;
    error.detail = payload || rawText || '';
    throw error;
  }

  if (Number(payload?.code) !== 200 || !payload?.data?.audioUrl) {
    const error = new Error(normalizeVoiceSynthesisErrorMessage(payload?.error?.message || payload?.message || '语音合成失败'));
    error.status = 502;
    error.detail = payload || '';
    throw error;
  }

  return {
    audioUrl: payload.data.audioUrl,
    workId: payload.data.workId || '',
    payload
  };
}

function createHttpError(message, status = 500, detail = '') {
  const error = new Error(message || '请求失败');
  error.status = status;
  error.detail = detail;
  return error;
}

function inferAudioFormatFromUrl(url) {
  try {
    const parsed = new URL(String(url || '').trim());
    return inferAudioFormat({ originalname: parsed.pathname || '', mimetype: '' });
  } catch {
    return inferAudioFormat({ originalname: String(url || '').trim(), mimetype: '' });
  }
}

function normalizeVoiceClonePayload(body) {
  const audioData = body?.audioData && typeof body.audioData === 'object' ? body.audioData : {};
  const extraParams = body?.extra_params && typeof body.extra_params === 'object' ? body.extra_params : {};
  return {
    token: normalizeBearerToken(body?.token),
    name: String(body?.name || body?.displayName || '').trim(),
    timbreId: String(body?.timbreId || '').trim(),
    speakerId: String(body?.speaker_id || body?.speakerId || '').trim(),
    audioData: {
      url: String(audioData?.url || '').trim(),
      base64: String(audioData?.base64 || '').trim(),
      format: String(audioData?.format || '').trim().toLowerCase(),
      text: String(audioData?.text || body?.audioText || '').trim()
    },
    language: Number(body?.language ?? 0) === 1 ? 1 : 0,
    demoText: String(extraParams?.demo_text || body?.sampleText || '').trim(),
    sourceAudioName: String(body?.sourceAudioName || body?.source_audio_name || '').trim(),
    sourceAudioFormat: String(body?.sourceAudioFormat || body?.source_audio_format || '').trim().toLowerCase()
  };
}

function normalizeVoiceSynthesisPayload(body) {
  const rawAudioParams = body?.audio_params && typeof body.audio_params === 'object'
    ? body.audio_params
    : (body?.audioParams && typeof body.audioParams === 'object' ? body.audioParams : {});
  const rawAdditions = body?.additions && typeof body.additions === 'object' ? body.additions : {};
  const formatCandidate = String(rawAudioParams?.format || '').trim().toLowerCase();
  const format = ['mp3', 'ogg_opus', 'pcm'].includes(formatCandidate) ? formatCandidate : 'mp3';
  const sampleRateCandidate = Number(rawAudioParams?.sampleRate ?? rawAudioParams?.sample_rate);
  const sampleRate = [8000, 16000, 22050, 24000, 32000, 44100, 48000].includes(sampleRateCandidate) ? sampleRateCandidate : 24000;
  const speechRate = clampNumber(rawAudioParams?.speechRate ?? rawAudioParams?.speech_rate, 0, -50, 100);
  const loudnessRate = clampNumber(rawAudioParams?.loudnessRate ?? rawAudioParams?.loudness_rate, 0, -50, 100);
  const emotion = String(rawAudioParams?.emotion || '').trim();
  const emotionScale = clampOptionalNumber(rawAudioParams?.emotionScale ?? rawAudioParams?.emotion_scale, 1, 5);
  const enableSubtitle = parseOptionalBoolean(rawAudioParams?.enableSubtitle ?? rawAudioParams?.enable_subtitle, false);
  const silenceDuration = clampOptionalNumber(rawAdditions?.silenceDuration ?? rawAdditions?.silence_duration, 0, 30000);
  const enableLanguageDetector = parseOptionalBoolean(rawAdditions?.enableLanguageDetector ?? rawAdditions?.enable_language_detector, false);
  const disableMarkdownFilter = parseOptionalBoolean(rawAdditions?.disableMarkdownFilter ?? rawAdditions?.disable_markdown_filter, false);
  const disableEmojiFilter = parseOptionalBoolean(rawAdditions?.disableEmojiFilter ?? rawAdditions?.disable_emoji_filter, false);
  const explicitLanguage = String((rawAdditions?.explicitLanguage ?? rawAdditions?.explicit_language) || '').trim();
  return {
    token: normalizeBearerToken(body?.token),
    text: String(body?.text || '').trim(),
    ssml: String(body?.ssml || '').trim(),
    timbreId: String(body?.timbreId || body?.timbre_id || '').trim(),
    speakerId: String(body?.speaker_id || body?.speakerId || body?.speaker || '').trim(),
    isStream: parseOptionalBoolean(body?.isStream ?? body?.is_stream, true),
    xApiResourceId: String(body?.x_api_resource_id || body?.xApiResourceId || '').trim(),
    model: String(body?.model || '').trim(),
    audioParams: {
      format,
      sampleRate,
      speechRate,
      loudnessRate,
      emotion,
      emotionScale,
      enableSubtitle
    },
    additions: {
      ...(silenceDuration === null ? {} : { silence_duration: silenceDuration }),
      ...(enableLanguageDetector ? { enable_language_detector: true } : {}),
      ...(disableMarkdownFilter ? { disable_markdown_filter: true } : {}),
      ...(disableEmojiFilter ? { disable_emoji_filter: true } : {}),
      ...(explicitLanguage ? { explicit_language: explicitLanguage } : {})
    }
  };
}

function buildProxySynthesisPayload(payload) {
  return {
    token: payload.token,
    ...(payload.text ? { text: payload.text } : {}),
    ...(payload.ssml ? { ssml: payload.ssml } : {}),
    ...(payload.timbreId ? { timbreId: payload.timbreId } : {}),
    ...(payload.speakerId ? { speaker_id: payload.speakerId } : {}),
    isStream: !!payload.isStream,
    ...(payload.xApiResourceId ? { x_api_resource_id: payload.xApiResourceId } : {}),
    ...(payload.model ? { model: payload.model } : {}),
    audio_params: {
      format: payload.audioParams.format,
      sample_rate: payload.audioParams.sampleRate,
      speech_rate: payload.audioParams.speechRate,
      loudness_rate: payload.audioParams.loudnessRate,
      ...(payload.audioParams.emotion ? { emotion: payload.audioParams.emotion } : {}),
      ...(payload.audioParams.emotionScale === null || payload.audioParams.emotionScale === undefined ? {} : { emotion_scale: payload.audioParams.emotionScale }),
      ...(payload.audioParams.enableSubtitle ? { enable_subtitle: true } : {})
    },
    ...(Object.keys(payload.additions).length > 0 ? { additions: payload.additions } : {})
  };
}

async function executeVoiceCloneRequest(payload) {
  if (!payload.token) {
    throw createHttpError('缺少 token 参数', 400);
  }
  if (!payload.name) {
    throw createHttpError('缺少音色名称 name', 400);
  }
  if (!payload.timbreId && !payload.speakerId) {
    throw createHttpError('timbreId与speaker_id不能同时为空', 400);
  }
  if (!payload.audioData.url && !payload.audioData.base64) {
    throw createHttpError('音频url或base64至少提供一个', 400);
  }
  if (payload.demoText && (payload.demoText.length < 4 || payload.demoText.length > 80)) {
    throw createHttpError('试听文本长度需在 4-80 字之间', 400);
  }

  const clonePayload = await requestVolcTtsJson('voice_clone', {
    token: payload.token,
    name: payload.name,
    ...(payload.timbreId ? { timbreId: payload.timbreId } : {}),
    ...(payload.speakerId ? { speaker_id: payload.speakerId } : {}),
    audioData: {
      ...(payload.audioData.url ? { url: payload.audioData.url } : {}),
      ...(payload.audioData.base64 ? { base64: payload.audioData.base64 } : {}),
      ...(payload.audioData.format ? { format: payload.audioData.format } : {}),
      ...(payload.audioData.text ? { text: payload.audioData.text } : {})
    },
    language: payload.language,
    ...(payload.demoText ? { extra_params: { demo_text: payload.demoText } } : {})
  });

  if (Number(clonePayload?.code) !== 200 || !clonePayload?.data?.timbre?.objectId) {
    throw createHttpError(clonePayload?.error?.message || clonePayload?.message || '音色复刻失败', 502, clonePayload || '');
  }

  const timbre = clonePayload.data.timbre;
  const primaryModel = extractPrimaryVoiceModel(timbre);
  const now = new Date().toISOString();
  const profile = upsertVoiceProfile({
    id: `VOICE-${Date.now()}`,
    name: payload.name,
    creation_mode: 'clone',
    speaker_id: timbre?.speaker_id || payload.speakerId,
    timbre_id: timbre?.objectId || payload.timbreId || '',
    sample_text: payload.demoText,
    source_audio_text: payload.audioData.text,
    source_audio_name: payload.sourceAudioName,
    source_audio_format: payload.sourceAudioFormat || payload.audioData.format || inferAudioFormatFromUrl(payload.audioData.url),
    text_prompt: '',
    language: payload.language,
    status: Number.isFinite(Number(timbre?.status)) ? Number(timbre.status) : null,
    status_label: mapVoiceCloneStatus(timbre?.status),
    demo_audio: primaryModel?.demo_audio || '',
    available_training_times: null,
    image_prompt_name: '',
    x_api_resource_id: Array.isArray(primaryModel?.x_api_resource_id) ? String(primaryModel.x_api_resource_id[0] || '') : '',
    model_version: String(primaryModel?.version || ''),
    icl_speaker_id: String(primaryModel?.icl_speaker_id || ''),
    occupied: !!timbre?.occupied,
    synthesized_audio_url: '',
    synthesized_work_id: '',
    last_synthesis_text: '',
    latest_audio_url: primaryModel?.demo_audio || '',
    message: clonePayload?.data?.tip || '音色复刻成功',
    request_id: clonePayload?.request_id || '',
    created_at: now,
    updated_at: now
  });

  return {
    clonePayload,
    profile
  };
}

function findVoiceProfileForSynthesis(payload) {
  const profiles = readDataFile('voice-profiles');
  if (payload.timbreId) {
    const byTimbreId = profiles.find((item) => item.timbre_id === payload.timbreId);
    if (byTimbreId) {
      return byTimbreId;
    }
  }

  if (payload.speakerId) {
    return profiles.find((item) => (
      String(item.icl_speaker_id || '').trim() === payload.speakerId
      || String(item.speaker_id || '').trim() === payload.speakerId
    )) || null;
  }

  return null;
}

function persistSynthesisProfile(profile, payload, synthesis) {
  if (!profile) {
    return null;
  }

  return upsertVoiceProfile({
    ...profile,
    synthesized_audio_url: synthesis.audioUrl,
    synthesized_work_id: synthesis.workId,
    last_synthesis_text: payload.text,
    last_synthesis_ssml: payload.ssml,
    last_synthesis_x_api_resource_id: payload.xApiResourceId || profile.x_api_resource_id || '',
    last_synthesis_model: payload.model,
    last_synthesis_format: payload.audioParams.format,
    last_synthesis_sample_rate: payload.audioParams.sampleRate,
    last_synthesis_speech_rate: payload.audioParams.speechRate,
    last_synthesis_loudness_rate: payload.audioParams.loudnessRate,
    last_synthesis_emotion: payload.audioParams.emotion,
    last_synthesis_emotion_scale: payload.audioParams.emotionScale,
    last_synthesis_enable_subtitle: !!payload.audioParams.enableSubtitle,
    last_synthesis_silence_duration: payload.additions?.silence_duration ?? null,
    last_synthesis_enable_language_detector: !!payload.additions?.enable_language_detector,
    last_synthesis_disable_markdown_filter: !!payload.additions?.disable_markdown_filter,
    last_synthesis_disable_emoji_filter: !!payload.additions?.disable_emoji_filter,
    last_synthesis_explicit_language: String(payload.additions?.explicit_language || '').trim(),
    latest_audio_url: synthesis.audioUrl || profile.latest_audio_url || profile.demo_audio || '',
    updated_at: new Date().toISOString()
  });
}

async function executeVoiceSynthesisRequest(payload) {
  if (!payload.token) {
    throw createHttpError('缺少 token 参数', 400);
  }
  if (!payload.text && !payload.ssml) {
    throw createHttpError('文本内容不能为空，text与ssml不能同时为空', 400);
  }

  const matchedProfile = findVoiceProfileForSynthesis(payload);

  if (payload.timbreId) {
    const proxyPayload = await requestVolcTtsJson('unidirectional', buildProxySynthesisPayload({
      ...payload,
      isStream: false
    }));

    if (Number(proxyPayload?.code) !== 200 || !proxyPayload?.data?.audioUrl) {
      throw createHttpError(proxyPayload?.error?.message || proxyPayload?.message || '语音合成失败', 502, proxyPayload || '');
    }

    const profile = persistSynthesisProfile(matchedProfile, payload, {
      audioUrl: proxyPayload.data.audioUrl,
      workId: proxyPayload.data.workId || ''
    });

    return {
      response: {
        ...proxyPayload,
        ...(profile ? { profile } : {})
      },
      profile
    };
  }

  if (!payload.speakerId) {
    throw createHttpError('音色id不能为空', 400);
  }

  const synthesis = await synthesizeVoiceAudio({
    token: payload.token,
    speaker: payload.speakerId,
    timbreId: matchedProfile?.timbre_id || '',
    text: payload.text,
    ssml: payload.ssml,
    xApiResourceId: payload.xApiResourceId || matchedProfile?.x_api_resource_id || '',
    model: payload.model,
    isStream: false,
    audioParams: payload.audioParams,
    additions: payload.additions
  });

  const profile = persistSynthesisProfile(matchedProfile, payload, synthesis);

  return {
    response: {
      code: 200,
      data: {
        workId: synthesis.workId,
        audioUrl: synthesis.audioUrl
      },
      ...(profile ? { profile } : {})
    },
    profile
  };
}

// 通用 JSON 数据文件读写
function readDataFile(name) {
  const p = path.join(DATA_DIR, `${name}.json`);
  if (!fs.existsSync(p)) { fs.writeFileSync(p, '[]', 'utf-8'); return []; }
  return JSON.parse(fs.readFileSync(p, 'utf-8'));
}

function writeDataFile(name, data) {
  fs.writeFileSync(path.join(DATA_DIR, `${name}.json`), JSON.stringify(data, null, 2), 'utf-8');
}

function isSafeRemoteUrl(url) {
  try {
    const parsed = new URL(url);
    return ['http:', 'https:'].includes(parsed.protocol);
  } catch {
    return false;
  }
}

function sanitizeFilename(filename) {
  const safeName = String(filename || '')
    .replace(/[<>:"/\\|?*\x00-\x1F]/g, '_')
    .trim();

  return safeName || `video-${Date.now()}.mp4`;
}

function ensureVideoFilename(filename, sourceUrl = '') {
  const safeName = sanitizeFilename(filename);
  if (path.extname(safeName)) {
    return safeName;
  }

  try {
    const parsed = new URL(sourceUrl);
    const sourceExt = path.extname(parsed.pathname || '').toLowerCase();
    if (sourceExt) {
      return `${safeName}${sourceExt}`;
    }
  } catch {}

  return `${safeName}.mp4`;
}

function ensureUniqueVideoFilename(filename) {
  const ext = path.extname(filename) || '.mp4';
  const baseName = path.basename(filename, ext);
  let candidate = filename;
  let counter = 1;

  while (fs.existsSync(path.join(DATA_VIDEO_DIR, candidate)) || fs.existsSync(path.join(LEGACY_VIDEO_DIR, candidate))) {
    candidate = `${baseName}-${Date.now()}-${counter}${ext}`;
    counter += 1;
  }

  return candidate;
}

function createManagedVideoEntry({ filename, title, description, tags, thumbnail, duration, resolution, awemeId, authorName, size }) {
  const ext = path.extname(filename).replace('.', '').toLowerCase() || 'mp4';
  const now = new Date().toISOString();

  return {
    id: `VID-${Date.now()}`,
    title: title || path.basename(filename, path.extname(filename)),
    filename,
    size: size || 0,
    duration: Number(duration) || 0,
    created_at: now,
    modified_at: now,
    category: 'downloaded',
    tags: Array.isArray(tags) ? tags : [],
    description: description || '',
    thumbnail: thumbnail || '',
    source: 'downloaded',
    aweme_id: awemeId || '',
    metadata: {
      resolution: resolution || '未知',
      format: ext,
      authorName: authorName || ''
    }
  };
}

function normalizeRemoteUrls(primaryUrl, urls = []) {
  return [primaryUrl, ...(Array.isArray(urls) ? urls : [])].filter((url, index, list) => (
    typeof url === 'string'
    && isSafeRemoteUrl(url)
    && list.indexOf(url) === index
  ));
}

async function fetchRemoteVideoResponse(urls, requestHeaders = {}) {
  let lastError = null;

  for (const currentUrl of urls) {
    try {
      const response = await fetch(currentUrl, {
        method: 'GET',
        headers: requestHeaders,
        redirect: 'follow'
      });

      if (!response.ok) {
        const detail = await response.text().catch(() => '');
        lastError = new Error(`远程下载失败: ${response.status} ${response.statusText}${detail ? ` ${detail.slice(0, 200)}` : ''}`);
        continue;
      }

      if (!response.body) {
        lastError = new Error('远程响应缺少视频流');
        continue;
      }

      return { url: currentUrl, response };
    } catch (error) {
      lastError = error;
    }
  }

  throw lastError || new Error('没有可用的远程视频地址');
}

// ==================== Whisper 转录 ====================

// POST /api/whisper/transcribe
// body: { videoId, language?, model? }
app.post('/api/whisper/transcribe', async (req, res) => {
  const { videoId, language = 'Chinese', model = 'base' } = req.body;

  if (!videoId) {
    return res.status(400).json({ error: '缺少 videoId 参数' });
  }

  // 从 manifest 查找视频
  const manifest = readManifest();
  const video = manifest.find(v => v.id === videoId);
  if (!video) {
    return res.status(404).json({ error: `未找到视频: ${videoId}` });
  }

  const videoPath = resolveVideoPath(video.filename);
  if (!fs.existsSync(videoPath)) {
    return res.status(404).json({ error: `视频文件不存在: ${video.filename}` });
  }

  // 为该视频创建专属输出目录
  const baseName = video.filename.replace(/\.[^.]+$/, '');
  const outputDir = path.join(WHISPER_DIR, baseName);
  if (!fs.existsSync(outputDir)) {
    fs.mkdirSync(outputDir, { recursive: true });
  }

  console.log(`🎙️ 开始 Whisper 转录: ${video.filename}`);
  console.log(`   模型: ${model}, 语言: ${language}`);
  console.log(`   输出目录: ${outputDir}`);

  // 执行 Whisper 命令
  const cmd = `whisper "${videoPath}" --model ${model} --language ${language} --output_dir "${outputDir}"`;

  try {
    const result = await new Promise((resolve, reject) => {
      const process = exec(cmd, {
        cwd: PROJECT_ROOT,
        timeout: 10 * 60 * 1000, // 10分钟超时
        maxBuffer: 10 * 1024 * 1024
      });

      let stdout = '';
      let stderr = '';

      process.stdout.on('data', (data) => {
        stdout += data;
        console.log(`   [whisper] ${data.toString().trim()}`);
      });

      process.stderr.on('data', (data) => {
        stderr += data;
      });

      process.on('close', (code) => {
        if (code === 0) {
          resolve({ stdout, stderr });
        } else {
          reject(new Error(`Whisper 退出码: ${code}\n${stderr}`));
        }
      });

      process.on('error', (err) => {
        reject(new Error(`无法启动 Whisper: ${err.message}`));
      });
    });

    // 读取生成的文件
    const txtFile = path.join(outputDir, `${baseName}.txt`);
    const srtFile = path.join(outputDir, `${baseName}.srt`);

    const transcript = fs.existsSync(txtFile) ? fs.readFileSync(txtFile, 'utf-8') : '';
    const srt = fs.existsSync(srtFile) ? fs.readFileSync(srtFile, 'utf-8') : '';

    if (!transcript) {
      return res.status(500).json({ error: 'Whisper 执行完成但未生成文字稿' });
    }

    // 更新 manifest 中该视频的 whisper 字段
    const whisperPaths = {
      transcript: `Whisper/${baseName}/${baseName}.txt`,
      srt: `Whisper/${baseName}/${baseName}.srt`
    };

    // 检查是否存在其他输出文件
    const jsonFile = path.join(outputDir, `${baseName}.json`);
    const vttFile = path.join(outputDir, `${baseName}.vtt`);
    const tsvFile = path.join(outputDir, `${baseName}.tsv`);
    if (fs.existsSync(jsonFile)) whisperPaths.segments = `Whisper/${baseName}/${baseName}.json`;

    video.whisper = whisperPaths;
    writeManifest(manifest);

    console.log(`✅ Whisper 转录完成: ${baseName}`);

    res.json({
      success: true,
      videoId: video.id,
      transcript,
      srt,
      whisper: whisperPaths,
      outputDir: `Whisper/${baseName}`
    });

  } catch (err) {
    console.error(`❌ Whisper 转录失败:`, err.message);
    res.status(500).json({
      error: `Whisper 转录失败: ${err.message}`,
      hint: '请确保已安装 Whisper: pip install openai-whisper'
    });
  }
});

// GET /api/whisper/status — 检查 Whisper 是否可用
app.get('/api/whisper/status', (req, res) => {
  exec('whisper --help', { timeout: 5000 }, (err) => {
    if (err) {
      res.json({ available: false, message: '未检测到 Whisper，请执行: pip install openai-whisper' });
    } else {
      res.json({ available: true, message: 'Whisper 已安装' });
    }
  });
});

// ==================== Manifest 管理 ====================

// GET /api/manifest — 获取完整 manifest
app.get('/api/manifest', (req, res) => {
  try {
    const manifest = readManifest();
    res.json(manifest);
  } catch (err) {
    res.status(500).json({ error: `读取 manifest 失败: ${err.message}` });
  }
});

// PUT /api/manifest/:videoId — 更新指定视频条目
app.put('/api/manifest/:videoId', (req, res) => {
  try {
    const manifest = readManifest();
    const idx = manifest.findIndex(v => v.id === req.params.videoId);
    if (idx === -1) {
      return res.status(404).json({ error: `未找到视频: ${req.params.videoId}` });
    }
    // 合并更新字段
    manifest[idx] = { ...manifest[idx], ...req.body };
    writeManifest(manifest);
    res.json({ success: true, video: manifest[idx] });
  } catch (err) {
    res.status(500).json({ error: `更新 manifest 失败: ${err.message}` });
  }
});

// POST /api/manifest — 添加新视频条目
app.post('/api/manifest', (req, res) => {
  try {
    const manifest = readManifest();
    const newEntry = req.body;
    if (!newEntry.id || !newEntry.filename) {
      return res.status(400).json({ error: '缺少 id 或 filename' });
    }
    // 检查重复
    if (manifest.find(v => v.id === newEntry.id)) {
      return res.status(409).json({ error: `视频 ${newEntry.id} 已存在` });
    }
    manifest.push(newEntry);
    writeManifest(manifest);
    res.json({ success: true, video: newEntry });
  } catch (err) {
    res.status(500).json({ error: `添加视频失败: ${err.message}` });
  }
});

// DELETE /api/manifest/:videoId — 删除指定视频条目及关联文件
app.delete('/api/manifest/:videoId', (req, res) => {
  try {
    const manifest = readManifest();
    const idx = manifest.findIndex(v => v.id === req.params.videoId);
    if (idx === -1) {
      return res.status(404).json({ error: `未找到视频: ${req.params.videoId}` });
    }

    const [video] = manifest.splice(idx, 1);
    const filename = typeof video.filename === 'string' ? video.filename : '';

    // 先清理关联文件，所有步骤都做容错；最后再持久化 manifest，避免中途异常导致状态不一致
    if (filename) {
      try {
        const videoPath = resolveVideoPath(filename);
        removeFileIfExists(videoPath);
      } catch (cleanupErr) {
        console.warn(`⚠️ 删除视频文件失败 (${filename}):`, cleanupErr.message);
      }
    } else {
      console.warn(`⚠️ 视频条目 ${video.id} 缺少 filename 字段，跳过文件清理`);
    }

    try {
      const remixFilePath = path.join(REMIXES_DIR, `${video.id}.json`);
      removeFileIfExists(remixFilePath);
    } catch (cleanupErr) {
      console.warn(`⚠️ 删除 remix 文件失败 (${video.id}):`, cleanupErr.message);
    }

    if (filename) {
      try {
        const baseName = filename.replace(/\.[^.]+$/, '');
        const whisperOutputDir = path.join(WHISPER_DIR, baseName);
        removeDirectoryIfExists(whisperOutputDir);
      } catch (cleanupErr) {
        console.warn(`⚠️ 删除 Whisper 输出目录失败 (${filename}):`, cleanupErr.message);
      }
    }

    writeManifest(manifest);

    console.log(`🗑️ 视频已删除: ${video.title || filename || video.id}`);
    res.json({ success: true, videoId: video.id, filename });
  } catch (err) {
    console.error('❌ DELETE /api/manifest 失败:', err);
    res.status(500).json({ error: `删除视频失败: ${err.message}` });
  }
});

// ==================== 视频上传 ====================

// POST /api/upload/video — 上传视频文件
app.post('/api/upload/video', upload.single('video'), (req, res) => {
  try {
    if (!req.file) {
      return res.status(400).json({ error: '未收到视频文件' });
    }

    const file = req.file;
    const filename = file.filename;
    const ext = path.extname(filename).replace('.', '').toLowerCase();

    // 生成视频 ID
    const videoId = `VID-${Date.now()}`;

    // 获取文件大小
    const fileStat = fs.statSync(file.path);

    // 创建 manifest 条目
    const videoEntry = {
      id: videoId,
      title: req.body.title || path.basename(filename, path.extname(filename)),
      filename: filename,
      size: fileStat.size,
      duration: 0, // 前端可以通过 video 元素获取
      category: 'uploaded',
      tags: req.body.tags ? JSON.parse(req.body.tags) : [],
      description: req.body.description || '用户上传的视频',
      source: 'uploaded',
      metadata: {
        resolution: '未知',
        format: ext || 'mp4'
      }
    };

    // 添加到 manifest
    const manifest = readManifest();
    manifest.push(videoEntry);
    writeManifest(manifest);

    console.log(`📤 视频上传成功: ${filename} (${(fileStat.size / 1024 / 1024).toFixed(1)}MB) → ${videoId}`);

    res.json({
      success: true,
      video: videoEntry,
      filepath: `/backend/video/${filename}`
    });
  } catch (err) {
    console.error('❌ 视频上传失败:', err.message);
    res.status(500).json({ error: `上传失败: ${err.message}` });
  }
});

// 上传错误处理
app.use((err, req, res, next) => {
  if (err instanceof multer.MulterError) {
    if (err.code === 'LIMIT_FILE_SIZE') {
      return res.status(413).json({ error: '文件大小超过限制（最大 500MB）' });
    }
    return res.status(400).json({ error: `上传错误: ${err.message}` });
  }
  if (err) {
    return res.status(400).json({ error: err.message });
  }
  next();
});

app.post('/api/remix/extract-audio', (req, res) => {
  const { videoId } = req.body || {};
  if (!videoId) {
    return res.status(400).json({ error: '缺少 videoId 参数' });
  }

  const manifest = readManifest();
  const video = manifest.find(v => v.id === videoId);
  if (!video) {
    return res.status(404).json({ error: `未找到视频: ${videoId}` });
  }

  const videoPath = resolveVideoPath(video.filename);
  if (!fs.existsSync(videoPath)) {
    return res.status(404).json({ error: `视频文件不存在: ${video.filename}` });
  }

  const safeBaseName = path.basename(video.filename, path.extname(video.filename)).replace(/[^a-zA-Z0-9._-]/g, '_') || `audio-${Date.now()}`;
  const outputFilename = `${safeBaseName}-${Date.now()}.wav`;
  const outputPath = path.join(DATA_REMIX_ASSET_DIR, outputFilename);

  const ffmpegArgs = ['-y', '-i', videoPath, '-vn', '-acodec', 'pcm_s16le', '-ar', '44100', '-ac', '2', outputPath];
  const process = spawn('ffmpeg', ffmpegArgs, { cwd: PROJECT_ROOT });

  let stderr = '';
  process.stderr.on('data', (data) => {
    stderr += data.toString();
  });

  process.on('error', (err) => {
    removeFileIfExists(outputPath);
    const message = /ENOENT/i.test(err.message)
      ? '未检测到 ffmpeg，请先安装 ffmpeg 并确保已加入系统 PATH 环境变量'
      : `无法启动 ffmpeg：${err.message}`;
    res.status(500).json({ error: message });
  });

  process.on('close', (code) => {
    if (code !== 0 || !fs.existsSync(outputPath)) {
      removeFileIfExists(outputPath);
      const lastErrorLine = stderr.split('\n').filter(Boolean).slice(-1)[0] || '';
      const normalizedMessage = /ffmpeg/i.test(stderr) && /not recognized|not found|no such file/i.test(stderr)
        ? '未检测到 ffmpeg，请先安装 ffmpeg 并确保已加入系统 PATH 环境变量'
        : `音频提取失败${lastErrorLine ? `: ${lastErrorLine}` : ''}`;
      return res.status(500).json({ error: normalizedMessage });
    }

    res.setHeader('Content-Type', 'audio/wav');
    res.setHeader('Content-Disposition', `attachment; filename="${outputFilename}"`);

    const stream = fs.createReadStream(outputPath);
    stream.on('close', () => {
      removeFileIfExists(outputPath);
    });
    stream.on('error', () => {
      removeFileIfExists(outputPath);
      if (!res.headersSent) {
        res.status(500).json({ error: '音频文件读取失败' });
      } else {
        res.end();
      }
    });
    stream.pipe(res);
  });
});

// POST /api/extract-audio-mp3 — 提取视频音轨为 MP3（轻量，适合发给 Gemini 音频识别）
app.post('/api/extract-audio-mp3', (req, res) => {
  const { videoId } = req.body || {};
  if (!videoId) {
    return res.status(400).json({ error: '缺少 videoId 参数' });
  }

  const manifest = readManifest();
  const video = manifest.find(v => v.id === videoId);
  if (!video) {
    console.warn(`⚠️ extract-audio-mp3: 未找到 videoId=${videoId}`);
    return res.status(404).json({ error: `未找到视频: ${videoId}` });
  }

  const videoPath = resolveVideoPath(video.filename);
  if (!fs.existsSync(videoPath)) {
    console.warn(`⚠️ extract-audio-mp3: 视频文件不存在: ${videoPath}`);
    return res.status(404).json({ error: `视频文件不存在: ${video.filename}` });
  }

  const safeBaseName = path.basename(video.filename, path.extname(video.filename)).replace(/[^a-zA-Z0-9._-]/g, '_') || `audio-${Date.now()}`;
  // 使用 AAC（ffmpeg 内置，无需 libmp3lame），封装为 m4a；Gemini 支持 audio/mp4
  const outputFilename = `${safeBaseName}-${Date.now()}.m4a`;
  const outputPath = path.join(DATA_REMIX_ASSET_DIR, outputFilename);
  const outputMimeType = 'audio/mp4';

  console.log(`🎵 开始音频提取: ${videoPath} → ${outputPath}`);

  // 64kbps 单声道 16kHz：体积小且足够语音识别
  const ffmpegArgs = ['-y', '-i', videoPath, '-vn', '-c:a', 'aac', '-b:a', '64k', '-ar', '16000', '-ac', '1', outputPath];
  const proc = spawn('ffmpeg', ffmpegArgs, { cwd: PROJECT_ROOT });

  let stderr = '';
  let responded = false;
  const safeRespond = (status, body) => {
    if (responded) return;
    responded = true;
    res.status(status).json(body);
  };
  proc.stderr.on('data', (data) => { stderr += data.toString(); });

  proc.on('error', (err) => {
    removeFileIfExists(outputPath);
    const message = /ENOENT/i.test(err.message)
      ? '未检测到 ffmpeg，请先安装 ffmpeg 并确保已加入系统 PATH 环境变量'
      : `无法启动 ffmpeg：${err.message}`;
    console.error(`❌ extract-audio-mp3 spawn error: ${err.message}`);
    safeRespond(500, { error: message });
  });

  proc.on('close', (code) => {
    if (code !== 0 || !fs.existsSync(outputPath)) {
      const tail = stderr.split('\n').filter(Boolean).slice(-5).join(' | ');
      console.error(`❌ ffmpeg exit code=${code} 输出文件存在=${fs.existsSync(outputPath)}`);
      console.error(`   stderr 末尾: ${tail}`);
      removeFileIfExists(outputPath);
      const lastErrorLine = stderr.split('\n').filter(Boolean).slice(-1)[0] || '';
      return safeRespond(500, { error: `音频提取失败 (exit=${code})${lastErrorLine ? `: ${lastErrorLine}` : ''}` });
    }

    const stats = fs.statSync(outputPath);
    const sizeMB = (stats.size / 1024 / 1024).toFixed(2);
    console.log(`🎵 音频提取完成: ${outputFilename} (${sizeMB}MB)`);

    // 返回 base64 编码的 mp3（方便前端直接发给 Gemini）
    const audioBuffer = fs.readFileSync(outputPath);
    const audioBase64 = audioBuffer.toString('base64');
    removeFileIfExists(outputPath);

    safeRespond(200, {
      success: true,
      audio: {
        base64: audioBase64,
        mimeType: outputMimeType,
        sizeMB: parseFloat(sizeMB),
        filename: outputFilename
      }
    });
  });
});

app.post('/api/remix/upload-asset', assetUpload.single('file'), async (req, res) => {
  try {
    if (!req.file) {
      return res.status(400).json({ error: '未收到素材文件' });
    }

    const mimeType = req.file.mimetype || 'application/octet-stream';
    const kind = mimeType.startsWith('audio/')
      ? 'audio'
      : mimeType.startsWith('video/')
        ? 'video'
        : 'image';
    const key = buildDigitalHumanAssetKey(req.file.originalname, kind);
    const token = buildQiniuUploadToken(key);
    const formData = new FormData();
    formData.append('token', token);
    formData.append('key', key);
    formData.append('file', new Blob([req.file.buffer], { type: mimeType }), path.basename(key));

    const response = await fetch(QINIU_UPLOAD_URL, {
      method: 'POST',
      body: formData
    });

    const text = await response.text();
    let payload = null;
    try {
      payload = text ? JSON.parse(text) : null;
    } catch {
      payload = null;
    }

    if (!response.ok) {
      return res.status(response.status).json({
        error: payload?.error || payload?.message || text || '七牛素材上传失败',
        detail: payload || text || ''
      });
    }

    const uploadedKey = payload?.key || key;
    const url = `${QINIU_CDN_DOMAIN.replace(/\/$/, '')}/${uploadedKey}`;
    if (!uploadedKey || !url) {
      return res.status(500).json({ error: '七牛未返回素材 Key', detail: payload || text || '' });
    }

    res.json({
      success: true,
      url,
      key: uploadedKey,
      mimeType,
      kind
    });
  } catch (error) {
    console.error('❌ 上传重塑素材失败:', error);
    res.status(500).json({ error: `上传重塑素材失败: ${error.message}` });
  }
});

// ==================== 文件操作 ====================

// GET /api/files/whisper/:videoId — 获取指定视频的 Whisper 输出文件列表
app.get('/api/files/whisper/:videoId', (req, res) => {
  try {
    const manifest = readManifest();
    const video = manifest.find(v => v.id === req.params.videoId);
    if (!video) {
      return res.status(404).json({ error: `未找到视频: ${req.params.videoId}` });
    }

    const baseName = video.filename.replace(/\.[^.]+$/, '');
    const outputDir = path.join(WHISPER_DIR, baseName);

    if (!fs.existsSync(outputDir)) {
      return res.json({ files: [], exists: false });
    }

    const files = fs.readdirSync(outputDir).map(f => ({
      name: f,
      path: `Whisper/${baseName}/${f}`,
      size: fs.statSync(path.join(outputDir, f)).size
    }));

    res.json({ files, exists: true });
  } catch (err) {
    res.status(500).json({ error: err.message });
  }
});

// GET /api/files/read — 读取项目内文件内容
app.get('/api/files/read', (req, res) => {
  const filePath = req.query.path;
  if (!filePath) {
    return res.status(400).json({ error: '缺少 path 参数' });
  }

  const fullPath = path.join(PROJECT_ROOT, filePath);

  // 安全检查：不允许读取项目目录外的文件
  if (!fullPath.startsWith(PROJECT_ROOT)) {
    return res.status(403).json({ error: '路径不在项目目录内' });
  }

  if (!fs.existsSync(fullPath)) {
    return res.status(404).json({ error: '文件不存在' });
  }

  const ext = path.extname(fullPath).toLowerCase();
  if (['.json'].includes(ext)) {
    res.json(JSON.parse(fs.readFileSync(fullPath, 'utf-8')));
  } else {
    res.type('text/plain').send(fs.readFileSync(fullPath, 'utf-8'));
  }
});

app.post('/api/download/video', (req, res) => {
  const {
    url,
    urls,
    filename,
    title,
    description,
    tags,
    thumbnail,
    duration,
    resolution,
    awemeId,
    authorName
  } = req.body || {};

  if (!url || typeof url !== 'string') {
    return res.status(400).json({ error: '缺少 url 参数' });
  }

  const candidateUrls = normalizeRemoteUrls(url, urls);
  if (candidateUrls.length === 0) {
    return res.status(400).json({ error: '无效的视频地址' });
  }

  const safeFilename = ensureUniqueVideoFilename(ensureVideoFilename(filename || title || awemeId || 'douyin-video.mp4', url));
  const filePath = path.join(DATA_VIDEO_DIR, safeFilename);
  const taskId = `DL-${Date.now()}-${crypto.randomBytes(4).toString('hex')}`;
  const task = {
    id: taskId,
    status: 'pending',
    progress: 0,
    downloadedBytes: 0,
    totalBytes: 0,
    filename: safeFilename,
    created_at: new Date().toISOString()
  };

  downloadTasks.set(taskId, task);
  res.json({ success: true, taskId, filename: safeFilename });

  (async () => {
    try {
      task.status = 'downloading';
      console.log(`📥 开始下载远程视频: ${safeFilename} ← ${candidateUrls[0]}`);

      const { url: resolvedUrl, response } = await fetchRemoteVideoResponse(candidateUrls, {
        'Accept': '*/*',
        'User-Agent': 'Mozilla/5.0',
        'Referer': 'https://www.douyin.com/',
        'Origin': 'https://www.douyin.com'
      });
      task.sourceUrl = resolvedUrl;

      const totalBytes = Number.parseInt(response.headers.get('content-length') || '0', 10) || 0;
      task.totalBytes = totalBytes;

      let downloadedBytes = 0;
      let chunkCount = 0;

      const progressStream = new Transform({
        transform(chunk, encoding, callback) {
          downloadedBytes += chunk.length;
          chunkCount += 1;
          task.downloadedBytes = downloadedBytes;
          task.progress = totalBytes > 0
            ? Math.min(99, Math.round((downloadedBytes / totalBytes) * 100))
            : Math.min(95, Math.max(task.progress || 0, Math.min(95, chunkCount)));
          callback(null, chunk);
        }
      });

      await pipeline(
        Readable.fromWeb(response.body),
        progressStream,
        fs.createWriteStream(filePath)
      );

      const stat = fs.statSync(filePath);
      const manifest = readManifest();
      const videoEntry = createManagedVideoEntry({
        filename: safeFilename,
        title,
        description,
        tags,
        thumbnail,
        duration,
        resolution,
        awemeId,
        authorName,
        size: stat.size
      });

      manifest.push(videoEntry);
      writeManifest(manifest);

      task.status = 'completed';
      task.progress = 100;
      task.completed_at = new Date().toISOString();
      task.video = videoEntry;

      console.log(`✅ 远程视频下载完成: ${safeFilename} (${(stat.size / 1024 / 1024).toFixed(1)}MB)`);
    } catch (error) {
      removeFileIfExists(filePath);
      task.status = 'failed';
      task.error = error.message;
      task.failed_at = new Date().toISOString();
      console.error('❌ 远程视频下载失败:', error);
    }
  })();
});

app.get('/api/download/video/:taskId', (req, res) => {
  const task = downloadTasks.get(req.params.taskId);
  if (!task) {
    return res.status(404).json({ error: '未找到下载任务' });
  }

  res.json(task);
});

// ==================== 视频流代理 ====================

app.get('/api/video-proxy', async (req, res) => {
  const { url, filename = 'douyin-video.mp4', download } = req.query;

  if (!url || typeof url !== 'string') {
    return res.status(400).json({ error: '缺少 url 参数' });
  }

  if (!isSafeRemoteUrl(url)) {
    return res.status(400).json({ error: '无效的视频地址' });
  }

  try {
    const upstreamHeaders = {
      'Accept': req.headers.accept || '*/*',
      'User-Agent': req.headers['user-agent'] || 'Mozilla/5.0',
      'Referer': 'https://www.douyin.com/',
      'Origin': 'https://www.douyin.com'
    };

    if (req.headers.range) {
      upstreamHeaders.Range = req.headers.range;
    }

    const response = await fetch(url, {
      method: 'GET',
      headers: upstreamHeaders,
      redirect: 'follow'
    });

    if (!response.ok && response.status !== 206) {
      const errorText = await response.text().catch(() => '');
      return res.status(response.status).json({
        error: '远程视频请求失败',
        status: response.status,
        detail: errorText
      });
    }

    res.status(response.status);

    const passthroughHeaders = [
      'content-type',
      'content-length',
      'content-range',
      'accept-ranges',
      'etag',
      'last-modified',
      'cache-control'
    ];

    passthroughHeaders.forEach((headerName) => {
      const value = response.headers.get(headerName);
      if (value) {
        res.setHeader(headerName, value);
      }
    });

    if (!response.headers.get('content-type')) {
      res.setHeader('Content-Type', 'video/mp4');
    }

    res.setHeader(
      'Content-Disposition',
      download === '1'
        ? `attachment; filename*=UTF-8''${encodeURIComponent(filename)}`
        : `inline; filename*=UTF-8''${encodeURIComponent(filename)}`
    );

    if (!response.body) {
      return res.end();
    }

    Readable.fromWeb(response.body).pipe(res);
  } catch (error) {
    console.error('视频代理失败:', error);
    res.status(500).json({ error: `视频代理失败: ${error.message}` });
  }
});

// ==================== AI 重塑记录 ====================

const REMIXES_DIR = path.join(DATA_DIR, 'remixes');
if (!fs.existsSync(REMIXES_DIR)) fs.mkdirSync(REMIXES_DIR, { recursive: true });

function readRemixes(videoId) {
  const p = path.join(REMIXES_DIR, `${videoId}.json`);
  if (!fs.existsSync(p)) return [];
  return JSON.parse(fs.readFileSync(p, 'utf-8'));
}

function writeRemixes(videoId, data) {
  fs.writeFileSync(path.join(REMIXES_DIR, `${videoId}.json`), JSON.stringify(data, null, 2), 'utf-8');
}

// GET /api/remixes/:videoId — 获取某视频的所有重塑记录
app.get('/api/remixes/:videoId', (req, res) => {
  res.json(readRemixes(req.params.videoId));
});

// POST /api/remixes/:videoId — 创建或更新一条重塑记录
// body: { remixId, ...remixData }
app.post('/api/remixes/:videoId', (req, res) => {
  const remixes = readRemixes(req.params.videoId);
  const { remixId } = req.body;

  const idx = remixes.findIndex(r => r.remixId === remixId);
  if (idx >= 0) {
    // 更新已有记录（合并 segments）
    remixes[idx] = { ...remixes[idx], ...req.body, updated_at: new Date().toISOString() };
  } else {
    // 新增记录
    remixes.unshift({ ...req.body, created_at: new Date().toISOString(), updated_at: new Date().toISOString() });
  }

  writeRemixes(req.params.videoId, remixes);
  res.json({ success: true });
});

// DELETE /api/remixes/:videoId/:remixId — 删除某条重塑记录
app.delete('/api/remixes/:videoId/:remixId', (req, res) => {
  let remixes = readRemixes(req.params.videoId);
  remixes = remixes.filter(r => r.remixId !== req.params.remixId);
  writeRemixes(req.params.videoId, remixes);
  res.json({ success: true });
});

// GET /api/remixes — 获取所有视频的重塑记录汇总
app.get('/api/remixes', (req, res) => {
  const files = fs.readdirSync(REMIXES_DIR).filter(f => f.endsWith('.json'));
  const all = {};
  files.forEach(f => {
    const videoId = f.replace('.json', '');
    all[videoId] = JSON.parse(fs.readFileSync(path.join(REMIXES_DIR, f), 'utf-8'));
  });
  res.json(all);
});

// ==================== 一键成片（Quickly 代理） ====================

const QUICKLY_APP_KEY = 'ZmNmOGRhNjYzZTAx';
const QUICKLY_APP_SECRET = 'eaa12154c248cad9159a9d6ea8bedf46';
const QUICKLY_ACCOUNT_ID = '12859_117409';
const QUICKLY_CALLBACK_URL = 'https://server.fmode.cn/api/functions/cut/onemerge';
const QUICKLY_RELAY_URL = 'https://server.fmode.cn/api/functions';

// POST /api/quickly/create — 代理一键成片请求（服务端签名）
app.post('/api/quickly/create', async (req, res) => {
  try {
    const { videoUrls, options = {} } = req.body;
    if (!videoUrls || !Array.isArray(videoUrls) || videoUrls.length === 0) {
      return res.status(400).json({ error: '缺少 videoUrls 参数' });
    }

    const timestamp = Date.now().toString();
    const signStr = timestamp + '#' + QUICKLY_APP_SECRET;
    const sign = crypto.createHash('md5').update(signStr).digest('hex');

    const materialList = videoUrls.map(url => ({ type: 'video', value: url }));
    const preId = timestamp;

    const apiBody = {
      account_id: QUICKLY_ACCOUNT_ID,
      callback_url: QUICKLY_CALLBACK_URL,
      material_list: materialList,
      tags: options.tags || '视频,AI生成',
      proportion: options.proportion || '9:16',
      video_duration: options.videoDuration || { min: 10, max: 30 },
      pre_id: preId,
      compose_number: 1,
      ai_voice: options.aiVoice ?? 1,
      ai_bgm: options.aiBgm ?? 1,
      ai_flower: 1,
      ai_subtitle: options.aiSubtitle ?? 0,
      original_voice: 0
    };

    const relayData = JSON.stringify({
      apiPath: '/v2/video/vlog/create',
      apiBody: apiBody,
      appKey: QUICKLY_APP_KEY,
      timestamp: timestamp,
      sign: sign
    });

    const body = JSON.stringify({ action: 'relay', relayData: relayData });

    console.log(`📦 一键成片 - timestamp=${timestamp}, sign=${sign}`);
    console.log(`   材料: ${videoUrls.length} 个视频`);

    // 使用 Node 原生 fetch 发送请求
    const response = await fetch(QUICKLY_RELAY_URL, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: body
    });

    const result = await response.json();
    console.log('📦 一键成片 - 响应:', JSON.stringify(result).substring(0, 300));

    res.json(result);
  } catch (err) {
    console.error('❌ 一键成片代理失败:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// POST /api/quickly/query — 代理查询一键成片结果（通过 Parse 云函数）
app.post('/api/quickly/query', async (req, res) => {
  try {
    const { taskId } = req.body;
    if (!taskId) return res.status(400).json({ error: '缺少 taskId 参数' });

    const body = JSON.stringify({
      id: 'sWvRr8RvPT',
      _ApplicationId: 'ncloudmaster',
      action: 'query',
      taskId: taskId
    });

    const QUICKLY_QUERY_URL = 'https://server.fmode.cn/api/functions';
    const response = await fetch(QUICKLY_QUERY_URL, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: body
    });

    const result = await response.json();
    res.json(result);
  } catch (err) {
    console.error('❌ 一键成片查询失败:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// ==================== 视频合成（图片+音频 → 视频）====================

const COMPOSITE_DIR = path.join(DATA_DIR, 'composite');
if (!fs.existsSync(COMPOSITE_DIR)) fs.mkdirSync(COMPOSITE_DIR, { recursive: true });

// 下载远程文件到本地
async function downloadFile(url, destPath) {
  const response = await fetch(url, { redirect: 'follow' });
  if (!response.ok) throw new Error(`下载失败 (${response.status}): ${url}`);
  const buffer = Buffer.from(await response.arrayBuffer());
  fs.writeFileSync(destPath, buffer);
  return destPath;
}

// 获取媒体时长（秒）。ffprobe format=duration 同时适用于音频与视频。
function getMediaDuration(mediaPath) {
  return new Promise((resolve, reject) => {
    const proc = spawn('ffprobe', [
      '-v', 'error', '-show_entries', 'format=duration',
      '-of', 'default=noprint_wrappers=1:nokey=1', mediaPath
    ]);
    let stdout = '';
    proc.stdout.on('data', d => stdout += d.toString());
    proc.on('error', reject);
    proc.on('close', code => {
      const dur = parseFloat(stdout.trim());
      if (code !== 0 || isNaN(dur)) reject(new Error('无法获取媒体时长'));
      else resolve(dur);
    });
  });
}
// 向后兼容别名
const getAudioDuration = getMediaDuration;

// 将图片转为 jpg（确保 ffmpeg 兼容性）
function convertImageToJpg(inputPath, outputPath) {
  return new Promise((resolve, reject) => {
    const proc = spawn('ffmpeg', ['-y', '-i', inputPath, '-frames:v', '1', outputPath]);
    let stderr = '';
    proc.stderr.on('data', d => stderr += d.toString());
    proc.on('error', reject);
    proc.on('close', code => {
      if (code !== 0) reject(new Error(`图片转换失败: ${stderr.split('\n').filter(Boolean).slice(-1)[0]}`));
      else resolve(outputPath);
    });
  });
}

// ====================================================================
// 拼接管线统一规格（所有段必须一致，否则 concat -c copy 会失败）：
//   视频：1920x1080 yuv420p h264_mf
//   音频：AAC 192k 44100Hz stereo
// ====================================================================
const SEG_VF = 'scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2:black';
const SEG_AUDIO_ARGS = ['-c:a', 'aac', '-b:a', '192k', '-ar', '44100', '-ac', '2'];

// 单个片段：图片 + 音频 → 视频（case A，原有逻辑）
function createSegmentVideo(imagePath, audioPath, outputPath, duration) {
  return new Promise(async (resolve, reject) => {
    try {
      // 先将图片统一转为 jpg 确保兼容性
      const jpgPath = imagePath.replace(/\.[^.]+$/, '') + '_converted.jpg';
      await convertImageToJpg(imagePath, jpgPath);

      const args = [
        '-y',
        '-loop', '1', '-i', jpgPath,
        '-i', audioPath,
        '-c:v', 'h264_mf',
        ...SEG_AUDIO_ARGS,
        '-vf', SEG_VF,
        '-pix_fmt', 'yuv420p',
        '-t', String(duration),
        '-shortest',
        outputPath
      ];
      const proc = spawn('ffmpeg', args);
      let stderr = '';
      proc.stderr.on('data', d => stderr += d.toString());
      proc.on('error', err => reject(new Error(/ENOENT/i.test(err.message) ? '未检测到 ffmpeg' : err.message)));
      proc.on('close', code => {
        removeFileIfExists(jpgPath);
        if (code !== 0) reject(new Error(`片段合成失败: ${stderr.split('\n').filter(Boolean).slice(-2).join(' ')}`));
        else resolve(outputPath);
      });
    } catch (err) {
      reject(err);
    }
  });
}

/**
 * Case B: 视频 + 音频 → 替换音轨，**按音频时长对齐**（不是 -shortest）。
 *
 * 对齐策略（音频是叙事主干，宁可冻结画面也不能丢解说）：
 *   - videoDuration >= audioDuration + 0.05  → `-t audioDuration` 截断视频
 *   - videoDuration <  audioDuration - 0.05  → `tpad=stop_mode=clone` 用末帧补齐到 audioDuration
 *   - 长度接近                                → 直接 `-t audioDuration`
 *
 * 输出统一规格（1920x1080 yuv420p）以便后续 concat -c copy。
 *
 * @param {number} audioDuration 音频时长（秒），必填
 * @param {number=} videoDuration 视频原时长（秒），可选；缺省时退化为旧的 -shortest 行为
 */
function createVideoAudioSegment(videoPath, audioPath, outputPath, audioDuration, videoDuration) {
  return new Promise((resolve, reject) => {
    const target = Number(audioDuration);
    if (!target || target <= 0) {
      reject(new Error('createVideoAudioSegment 需要正数 audioDuration'));
      return;
    }

    // 构建 -vf 滤镜链。若视频短于音频，append tpad 冻结末帧补齐。
    let vfChain = SEG_VF;
    let needPad = false;
    if (typeof videoDuration === 'number' && videoDuration > 0 &&
        videoDuration < target - 0.05) {
      const padSec = (target - videoDuration).toFixed(3);
      vfChain += `,tpad=stop_mode=clone:stop_duration=${padSec}`;
      needPad = true;
    }

    const args = [
      '-y',
      '-i', videoPath,
      '-i', audioPath,
      '-map', '0:v:0',
      '-map', '1:a:0',
      '-c:v', 'h264_mf',
      '-vf', vfChain,
      '-pix_fmt', 'yuv420p',
      ...SEG_AUDIO_ARGS,
      '-t', String(target),
      outputPath,
    ];
    console.log(`    ↳ case B align: audio=${target.toFixed(2)}s, video=${videoDuration ? videoDuration.toFixed(2) + 's' : '?'}, ${needPad ? 'PAD freeze last frame' : 'TRIM/EXACT'}`);
    const proc = spawn('ffmpeg', args);
    let stderr = '';
    proc.stderr.on('data', d => stderr += d.toString());
    proc.on('error', err => reject(new Error(/ENOENT/i.test(err.message) ? '未检测到 ffmpeg' : err.message)));
    proc.on('close', code => {
      if (code !== 0) reject(new Error(`视频+音频片段合成失败: ${stderr.split('\n').filter(Boolean).slice(-2).join(' ')}`));
      else resolve(outputPath);
    });
  });
}

/**
 * Case C: 纯视频段 → 加静音轨并重编码到统一规格。
 * 用于「无解说配音」场景。视频原音轨被丢弃。
 */
function createVideoOnlySegment(videoPath, outputPath) {
  return new Promise((resolve, reject) => {
    const args = [
      '-y',
      '-i', videoPath,
      '-f', 'lavfi', '-i', 'anullsrc=channel_layout=stereo:sample_rate=44100',
      '-map', '0:v:0',
      '-map', '1:a:0',
      '-c:v', 'h264_mf',
      '-vf', SEG_VF,
      '-pix_fmt', 'yuv420p',
      ...SEG_AUDIO_ARGS,
      '-shortest',
      outputPath,
    ];
    const proc = spawn('ffmpeg', args);
    let stderr = '';
    proc.stderr.on('data', d => stderr += d.toString());
    proc.on('error', err => reject(new Error(/ENOENT/i.test(err.message) ? '未检测到 ffmpeg' : err.message)));
    proc.on('close', code => {
      if (code !== 0) reject(new Error(`纯视频片段合成失败: ${stderr.split('\n').filter(Boolean).slice(-2).join(' ')}`));
      else resolve(outputPath);
    });
  });
}

/**
 * Case D: 图片 + 静音 → 静态画面段（指定时长）。
 * 用于「图片 + 无配音」组合，duration 由调用方决定（默认 3s）。
 */
function createImageOnlySegment(imagePath, outputPath, duration) {
  return new Promise(async (resolve, reject) => {
    try {
      const jpgPath = imagePath.replace(/\.[^.]+$/, '') + '_converted.jpg';
      await convertImageToJpg(imagePath, jpgPath);
      const args = [
        '-y',
        '-loop', '1', '-i', jpgPath,
        '-f', 'lavfi', '-i', 'anullsrc=channel_layout=stereo:sample_rate=44100',
        '-map', '0:v:0',
        '-map', '1:a:0',
        '-c:v', 'h264_mf',
        '-vf', SEG_VF,
        '-pix_fmt', 'yuv420p',
        ...SEG_AUDIO_ARGS,
        '-t', String(duration),
        '-shortest',
        outputPath,
      ];
      const proc = spawn('ffmpeg', args);
      let stderr = '';
      proc.stderr.on('data', d => stderr += d.toString());
      proc.on('error', err => reject(new Error(/ENOENT/i.test(err.message) ? '未检测到 ffmpeg' : err.message)));
      proc.on('close', code => {
        removeFileIfExists(jpgPath);
        if (code !== 0) reject(new Error(`静音图片片段合成失败: ${stderr.split('\n').filter(Boolean).slice(-2).join(' ')}`));
        else resolve(outputPath);
      });
    } catch (err) {
      reject(err);
    }
  });
}

/**
 * 段调度：根据 segment 字段路由到 4 种 case 之一。
 *
 * 输入字段：
 *   - imageUrl?: 图片 URL
 *   - videoUrl?: 视频 URL（如即梦图生视频结果；优先级高于 imageUrl）
 *   - audioUrl?: 音频 URL（可选，缺省视为静音段）
 *   - duration?: 静态图模式下的画面停留秒数（默认 3）
 *
 * 路由：
 *   case A: imageUrl + audioUrl     → createSegmentVideo（按音频时长）
 *   case B: videoUrl + audioUrl     → createVideoAudioSegment（按短的）
 *   case C: videoUrl 无 audioUrl    → createVideoOnlySegment（按视频原长）
 *   case D: imageUrl 无 audioUrl    → createImageOnlySegment（按 duration）
 *
 * @returns {Promise<{ path: string, duration: number|null, mode: 'A'|'B'|'C'|'D' }>}
 */
async function composeOneSegment({ seg, jobDir, i }) {
  const segVideoPath = path.join(jobDir, `seg-${i}.mp4`);
  const hasImage = !!seg.imageUrl;
  const hasVideo = !!seg.videoUrl;
  const hasAudio = !!seg.audioUrl;

  if (!hasImage && !hasVideo) {
    throw new Error(`片段 ${seg.id != null ? seg.id : i} 缺少 imageUrl/videoUrl`);
  }

  // 下载音频（若有）
  let audioPath = null;
  let audioDuration = null;
  if (hasAudio) {
    const ext = (seg.audioUrl.match(/\.(mp3|wav|aac|ogg|m4a)/i) || ['.mp3'])[0] || '.mp3';
    audioPath = path.join(jobDir, `audio-${i}${ext}`);
    await downloadFile(seg.audioUrl, audioPath);
    audioDuration = await getAudioDuration(audioPath);
  }

  if (hasVideo) {
    const videoPath = path.join(jobDir, `video-${i}.mp4`);
    await downloadFile(seg.videoUrl, videoPath);

    // 探测原视频时长用于音频对齐（trim 或 freeze-last-frame pad）；
    // 探测失败 → 退化为旧的 -shortest 语义，仍能产出可用片段。
    let videoDuration;
    try {
      videoDuration = await getMediaDuration(videoPath);
    } catch (e) {
      console.warn(`  ⚠️  片段 ${i + 1} 探测视频时长失败，退化为 -shortest 对齐：`, e?.message || e);
    }
    if (hasAudio) {
      await createVideoAudioSegment(videoPath, audioPath, segVideoPath, audioDuration, videoDuration);
      return { path: segVideoPath, duration: audioDuration, mode: 'B' };
    } else {
      await createVideoOnlySegment(videoPath, segVideoPath);
      return { path: segVideoPath, duration: null, mode: 'C' };
    }
  }

  // hasImage
  const ext = (seg.imageUrl.match(/\.(jpg|jpeg|png|webp|gif)/i) || ['.jpg'])[0] || '.jpg';
  const imgPath = path.join(jobDir, `img-${i}${ext}`);
  await downloadFile(seg.imageUrl, imgPath);

  if (hasAudio) {
    await createSegmentVideo(imgPath, audioPath, segVideoPath, audioDuration);
    return { path: segVideoPath, duration: audioDuration, mode: 'A' };
  } else {
    const dur = Math.max(0.5, Number(seg.duration) || 3);
    await createImageOnlySegment(imgPath, segVideoPath, dur);
    return { path: segVideoPath, duration: dur, mode: 'D' };
  }
}

// 拼接多个视频片段
function concatVideos(segmentPaths, outputPath) {
  return new Promise((resolve, reject) => {
    // 创建 concat 文件列表
    const listPath = outputPath + '.txt';
    const listContent = segmentPaths.map(p => `file '${p.replace(/\\/g, '/')}'`).join('\n');
    fs.writeFileSync(listPath, listContent, 'utf-8');

    const args = [
      '-y', '-f', 'concat', '-safe', '0',
      '-i', listPath,
      '-c', 'copy',
      outputPath
    ];
    const proc = spawn('ffmpeg', args);
    let stderr = '';
    proc.stderr.on('data', d => stderr += d.toString());
    proc.on('error', err => reject(new Error(/ENOENT/i.test(err.message) ? '未检测到 ffmpeg' : err.message)));
    proc.on('close', code => {
      removeFileIfExists(listPath);
      if (code !== 0) reject(new Error(`视频拼接失败: ${stderr.split('\n').filter(Boolean).slice(-2).join(' ')}`));
      else resolve(outputPath);
    });
  });
}

// POST /api/video/composite — 合成视频（图片+音频 → 最终视频）
app.post('/api/video/composite', async (req, res) => {
  const { segments, title } = req.body;
  // segments: [{ imageUrl, audioUrl, id }]
  if (!Array.isArray(segments) || segments.length === 0) {
    return res.status(400).json({ error: '缺少 segments 参数' });
  }

  const jobId = `VG-${Date.now()}`;
  const jobDir = path.join(COMPOSITE_DIR, jobId);
  fs.mkdirSync(jobDir, { recursive: true });

  try {
    console.log(`🎬 开始合成视频: ${jobId}, ${segments.length} 个片段`);

    // 1. 下载并合成每段（四态分发：image+audio / video+audio / video-only / image-only）
    const segmentPaths = [];
    for (let i = 0; i < segments.length; i++) {
      const seg = segments[i];
      if (!seg.imageUrl && !seg.videoUrl) {
        console.warn(`⚠️ 片段 ${seg.id || i} 缺少 imageUrl/videoUrl，跳过`);
        continue;
      }
      console.log(`  📥 处理片段 ${i + 1}/${segments.length}...`);
      const { path: segPath, duration, mode } = await composeOneSegment({ seg, jobDir, i });
      console.log(`  🎞️ 已完成片段 ${i + 1}/${segments.length} [mode=${mode}${duration ? `, ${duration.toFixed(1)}s` : ''}]`);
      segmentPaths.push(segPath);
    }

    if (segmentPaths.length === 0) {
      return res.status(400).json({ error: '没有有效的素材片段' });
    }

    // 2. 拼接所有片段
    const safeTitle = String(title || 'video').replace(/[^a-zA-Z0-9\u4e00-\u9fff_-]/g, '_').substring(0, 50);
    const finalFilename = `${safeTitle}-${jobId}.mp4`;
    const finalPath = path.join(COMPOSITE_DIR, finalFilename);

    console.log(`  🔗 拼接 ${segmentPaths.length} 个片段...`);

    if (segmentPaths.length === 1) {
      // 只有一个片段，直接复制
      fs.copyFileSync(segmentPaths[0], finalPath);
    } else {
      await concatVideos(segmentPaths, finalPath);
    }

    // 3. 清理临时文件
    try {
      fs.rmSync(jobDir, { recursive: true, force: true });
    } catch {}

    const fileSize = fs.statSync(finalPath).size;
    console.log(`✅ 视频合成完成: ${finalFilename} (${(fileSize / 1024 / 1024).toFixed(1)}MB)`);

    res.json({
      success: true,
      videoUrl: `/api/video/composite/${finalFilename}`,
      filename: finalFilename,
      size: fileSize,
      segments: segmentPaths.length
    });

  } catch (err) {
    console.error(`❌ 视频合成失败:`, err.message);
    // 清理
    try { fs.rmSync(jobDir, { recursive: true, force: true }); } catch {}
    res.status(500).json({ error: `视频合成失败: ${err.message}` });
  }
});

/**
 * POST /api/video/composite/stream — SSE 流式合成端点
 *
 * 与 /api/video/composite 功能一致，但通过 Server-Sent Events 推送实时进度，
 * 用于 P3/P4 等长耗时合成任务，替换前端的"假定时器进度"。
 *
 * 事件类型：
 *   - event: stage         { stage: 'download'|'compose'|'concat'|'cleanup', message }
 *   - event: progress      { stage, current, total, percent }
 *   - event: done          { videoUrl, filename, size, segments }
 *   - event: error         { error }
 */
app.post('/api/video/composite/stream', async (req, res) => {
  const { segments, title } = req.body || {};
  if (!Array.isArray(segments) || segments.length === 0) {
    return res.status(400).json({ error: '缺少 segments 参数' });
  }

  // SSE 头
  res.setHeader('Content-Type', 'text/event-stream');
  res.setHeader('Cache-Control', 'no-cache');
  res.setHeader('Connection', 'keep-alive');
  res.flushHeaders?.();

  const emit = (event, data) => {
    res.write(`event: ${event}\n`);
    res.write(`data: ${JSON.stringify(data)}\n\n`);
  };

  const jobId = `VG-${Date.now()}`;
  const jobDir = path.join(COMPOSITE_DIR, jobId);
  fs.mkdirSync(jobDir, { recursive: true });

  // —— 心跳：长时间静默会被代理 / 浏览器空闲 TCP 关掉。
  // 每 10 秒写一个 SSE 注释行（`: ...\n\n`），客户端 reader 会忽略它。
  let finished = false;
  const heartbeat = setInterval(() => {
    if (finished) return;
    try { res.write(`: hb ${Date.now()}\n\n`); } catch {}
  }, 10000);

  // —— 客户端真正断开的检测：
  //
  // ❌ 不能用 `req.on('close')`。Node 16+ 中 IncomingMessage 的 close
  //    事件会在请求体被 express.json() 完整读取后立即触发（这是 Node 行为变更
  //    的常见陷阱），导致刚进 loop 就被误判为「客户端断开」。
  //
  // ✅ 正确做法：监听 `res.on('close')`。该事件只在响应连接被对端
  //    在 res.end() 之前提前关闭时触发；服务端主动 res.end() 不会触发。
  let aborted = false;
  res.on('close', () => {
    if (!finished) {
      aborted = true;
      console.warn(`⚠️ [SSE] 客户端断开 ${jobId}`);
    }
  });

  const cleanup = () => {
    finished = true;
    clearInterval(heartbeat);
  };

  try {
    console.log(`🎬 [SSE] 开始合成视频: ${jobId}, ${segments.length} 个片段`);
    emit('stage', { stage: 'download', message: `开始处理 ${segments.length} 段素材...` });

    const segmentPaths = [];
    const total = segments.length;
    for (let i = 0; i < total; i++) {
      if (aborted) throw new Error('客户端已断开');
      const seg = segments[i];
      if (!seg.imageUrl && !seg.videoUrl) {
        console.warn(`⚠️ 片段 ${seg.id || i} 缺少 imageUrl/videoUrl，跳过`);
        continue;
      }

      emit('progress', { stage: 'download', current: i + 1, total, percent: Math.round((i / total) * 100), message: `处理素材 ${i + 1}/${total}` });

      const { path: segPath, duration, mode } = await composeOneSegment({ seg, jobDir, i });
      segmentPaths.push(segPath);

      const durLabel = duration ? `${duration.toFixed(1)}s` : '原长';
      emit('progress', { stage: 'compose', current: i + 1, total, percent: Math.round(((i + 1) / total) * 100), message: `已完成 ${i + 1}/${total} 段（${durLabel}, mode=${mode}）` });
    }

    if (segmentPaths.length === 0) {
      throw new Error('没有有效的素材片段');
    }

    const safeTitle = String(title || 'video').replace(/[^a-zA-Z0-9\u4e00-\u9fff_-]/g, '_').substring(0, 50);
    const finalFilename = `${safeTitle}-${jobId}.mp4`;
    const finalPath = path.join(COMPOSITE_DIR, finalFilename);

    emit('stage', { stage: 'concat', message: `拼接 ${segmentPaths.length} 个片段...` });

    if (segmentPaths.length === 1) {
      fs.copyFileSync(segmentPaths[0], finalPath);
    } else {
      await concatVideos(segmentPaths, finalPath);
    }

    emit('stage', { stage: 'cleanup', message: '清理临时文件...' });
    try { fs.rmSync(jobDir, { recursive: true, force: true }); } catch {}

    const fileSize = fs.statSync(finalPath).size;
    console.log(`✅ [SSE] 视频合成完成: ${finalFilename} (${(fileSize / 1024 / 1024).toFixed(1)}MB)`);

    emit('done', {
      success: true,
      videoUrl: `/api/video/composite/${finalFilename}`,
      filename: finalFilename,
      size: fileSize,
      segments: segmentPaths.length,
    });
    cleanup();
    res.end();
  } catch (err) {
    console.error(`❌ [SSE] 视频合成失败:`, err.message);
    try { fs.rmSync(jobDir, { recursive: true, force: true }); } catch {}
    emit('error', { error: `视频合成失败: ${err.message}` });
    cleanup();
    res.end();
  }
});

// GET /api/video/composite/:filename — 下载合成视频
app.get('/api/video/composite/:filename', (req, res) => {
  const filePath = path.join(COMPOSITE_DIR, req.params.filename);
  if (!fs.existsSync(filePath)) {
    return res.status(404).json({ error: '视频文件不存在' });
  }
  res.setHeader('Content-Type', 'video/mp4');
  fs.createReadStream(filePath).pipe(res);
});

// ==================== 声音训练辅助：自动选择未训练的 speaker_id ====================

// 已被认为"已训练 / 已占用"的状态枚举（trainStatus 文档中的 State 值）
const VOICE_TRAINED_STATES = new Set(['training', 'success', 'active', 'expired', 'reclaimed']);
const DEFAULT_VOICE_TOKEN = process.env.VOLC_TTS_TOKEN || 'Bearer r:f0333969e312a40e4703e8fe4ed1c600';

// 从 trainStatus 响应中尽力解析出已被训练 / 占用的 speaker_id 集合
function collectTrainedSpeakerIdsFromResponse(payload) {
  const found = new Set();
  const seen = new WeakSet();
  const visit = (node) => {
    if (!node || typeof node !== 'object') return;
    if (seen.has(node)) return;
    seen.add(node);
    if (Array.isArray(node)) { node.forEach(visit); return; }
    const speakerId = node.speaker_id || node.SpeakerID || node.speakerId || node.Speaker_id || node.speakerID;
    const state = node.State || node.state || node.status || node.Status;
    if (typeof speakerId === 'string' && /^S_[A-Za-z0-9]+$/.test(speakerId.trim())) {
      const stateLower = String(state || '').trim().toLowerCase();
      if (stateLower && VOICE_TRAINED_STATES.has(stateLower)) {
        found.add(speakerId.trim());
      }
    }
    Object.values(node).forEach(visit);
  };
  visit(payload);
  return found;
}

// POST /api/voice/auto-speaker-id — 自动挑选一个未训练 / 未占用的 speaker_id
app.post('/api/voice/auto-speaker-id', async (req, res) => {
  try {
    const pool = readVoiceSpeakerIdOptions();
    if (pool.length === 0) {
      return res.status(500).json({ error: '本地未配置 speaker_id 池（docs/音色创建/speaker_id.md 为空）' });
    }

    const profiles = readDataFile('voice-profiles');
    const usedLocally = new Set(
      profiles
        .map((p) => String(p?.speaker_id || '').trim())
        .filter((id) => /^S_[A-Za-z0-9]+$/.test(id))
    );

    const token = normalizeBearerToken(req.body?.token) || DEFAULT_VOICE_TOKEN;

    let usedRemotely = new Set();
    let remoteOk = false;
    let remoteError = '';
    try {
      const trainStatusPayload = await requestVolcTtsJson('trainStatus', {
        token,
        speakerIdList: pool
      });
      usedRemotely = collectTrainedSpeakerIdsFromResponse(trainStatusPayload);
      remoteOk = true;
    } catch (e) {
      const detail = e?.detail;
      const detailText = typeof detail === 'string'
        ? detail
        : (detail ? JSON.stringify(detail) : '');
      remoteError = e?.message || detailText || (typeof e === 'string' ? e : (e ? JSON.stringify(e) : 'trainStatus 调用失败'));
    }

    const used = new Set([...usedLocally, ...usedRemotely]);
    const available = pool.find((id) => !used.has(id));

    if (!available) {
      return res.status(409).json({
        error: '当前所有候选 speaker_id 均已被训练或占用，请补充新的 speaker_id',
        pool,
        used: [...used],
        used_local: [...usedLocally],
        used_remote: [...usedRemotely],
        remote_check: remoteOk,
        remote_error: remoteError || undefined
      });
    }

    res.json({
      speaker_id: available,
      pool,
      used_local: [...usedLocally],
      used_remote: [...usedRemotely],
      remote_check: remoteOk,
      remote_error: remoteError || undefined
    });
  } catch (err) {
    res.status(500).json({ error: err?.message || '检测可用 speaker_id 失败' });
  }
});

// POST /api/voice-profiles/sync — 前端复刻成功后回写本地占用记录
// 临时方案：远程 trainStatus 不稳定，使用 data/voice-profiles.json 作为 speaker_id 占用源
app.post('/api/voice-profiles/sync', (req, res) => {
  try {
    const body = req.body || {};
    const speakerId = String(body.speaker_id || '').trim();
    const timbreId = String(body.timbre_id || body.id || '').trim();
    if (!/^S_[A-Za-z0-9]+$/.test(speakerId)) {
      return res.status(400).json({ error: '缺少有效的 speaker_id' });
    }
    if (!timbreId) {
      return res.status(400).json({ error: '缺少 timbre_id / id' });
    }

    const nowIso = new Date().toISOString();
    const profile = {
      id: timbreId,
      name: String(body.name || '').trim() || '未命名音色',
      creation_mode: 'clone',
      speaker_id: speakerId,
      timbre_id: timbreId,
      demo_audio: String(body.demo_audio || '').trim(),
      latest_audio_url: String(body.latest_audio_url || body.demo_audio || '').trim(),
      x_api_resource_id: String(body.x_api_resource_id || '').trim(),
      icl_speaker_id: String(body.icl_speaker_id || '').trim(),
      model_version: String(body.model_version || '').trim(),
      status: body.status === undefined || body.status === null ? null : body.status,
      status_label: String(body.status_label || '').trim(),
      message: String(body.message || '').trim(),
      created_at: body.created_at || nowIso,
      updated_at: nowIso
    };

    const saved = upsertVoiceProfile(profile);
    res.json({ success: true, profile: saved });
  } catch (err) {
    res.status(500).json({ error: err?.message || '保存音色记录失败' });
  }
});

// ==================== 任务管理 ====================

// GET /api/tasks — 获取所有任务
app.get('/api/tasks', (req, res) => {
  res.json(readDataFile('tasks'));
});

// POST /api/tasks — 创建新任务
app.post('/api/tasks', (req, res) => {
  const tasks = readDataFile('tasks');
  const task = { ...req.body, created_at: new Date().toISOString(), updated_at: new Date().toISOString() };
  // 确保始终有有效 ID（即使前端传了空 ID）
  if (!task.id) task.id = `TASK-${Date.now()}`;
  tasks.unshift(task);
  writeDataFile('tasks', tasks);
  res.json({ success: true, task });
});

// PUT /api/tasks/:id — 更新任务
app.put('/api/tasks/:id', (req, res) => {
  const tasks = readDataFile('tasks');
  const idx = tasks.findIndex(t => t.id === req.params.id);
  if (idx === -1) return res.status(404).json({ error: `任务不存在: ${req.params.id}` });
  tasks[idx] = { ...tasks[idx], ...req.body, updated_at: new Date().toISOString() };
  writeDataFile('tasks', tasks);
  res.json({ success: true, task: tasks[idx] });
});

// DELETE /api/tasks/:id — 删除任务
app.delete('/api/tasks/:id', (req, res) => {
  let tasks = readDataFile('tasks');
  const len = tasks.length;
  tasks = tasks.filter(t => t.id !== req.params.id);
  if (tasks.length === len) return res.status(404).json({ error: `任务不存在: ${req.params.id}` });
  writeDataFile('tasks', tasks);
  res.json({ success: true });
});

// ==================== 生成历史 ====================

// GET /api/history — 获取历史记录
app.get('/api/history', (req, res) => {
  res.json(readDataFile('history'));
});

// POST /api/history — 添加历史记录
app.post('/api/history', (req, res) => {
  const history = readDataFile('history');
  const record = { id: `HIS-${Date.now()}`, created_at: new Date().toISOString(), ...req.body };
  history.unshift(record);
  writeDataFile('history', history);
  res.json({ success: true, record });
});

// DELETE /api/history/:id — 删除历史记录
app.delete('/api/history/:id', (req, res) => {
  let history = readDataFile('history');
  const len = history.length;
  history = history.filter(h => h.id !== req.params.id);
  if (history.length === len) return res.status(404).json({ error: `记录不存在: ${req.params.id}` });
  writeDataFile('history', history);
  res.json({ success: true });
});

// DELETE /api/history — 清空所有历史
app.delete('/api/history', (req, res) => {
  writeDataFile('history', []);
  res.json({ success: true });
});

// ==================== 生成结果 ====================

// GET /api/results — 获取所有结果
app.get('/api/results', (req, res) => {
  res.json(readDataFile('results'));
});

// POST /api/results — 添加结果
app.post('/api/results', (req, res) => {
  const results = readDataFile('results');
  const result = { id: `RES-${Date.now()}`, created_at: new Date().toISOString(), ...req.body };
  results.unshift(result);
  writeDataFile('results', results);
  res.json({ success: true, result });
});

// PUT /api/results/:id — 更新结果
app.put('/api/results/:id', (req, res) => {
  const results = readDataFile('results');
  const idx = results.findIndex(r => r.id === req.params.id);
  if (idx === -1) return res.status(404).json({ error: `结果不存在: ${req.params.id}` });
  results[idx] = { ...results[idx], ...req.body };
  writeDataFile('results', results);
  res.json({ success: true, result: results[idx] });
});

// DELETE /api/results/:id — 删除结果
app.delete('/api/results/:id', (req, res) => {
  let results = readDataFile('results');
  const len = results.length;
  results = results.filter(r => r.id !== req.params.id);
  if (results.length === len) return res.status(404).json({ error: `结果不存在: ${req.params.id}` });
  writeDataFile('results', results);
  res.json({ success: true });
});

// ==================== LLM 大模型代理 ====================

const LLM_BASE_URL = 'http://server.fmode.cn:9999';
const LLM_API_KEY = 'sk-MFBOnsAtZiqlwwMgMLKCFmPy55pMohQEGMqsIw3aJrIgvoEO';

// POST /api/llm/chat — OpenAI ChatCompletions 代理
app.post('/api/llm/chat', async (req, res) => {
  try {
    const { model, messages, temperature, max_tokens, stream, ...rest } = req.body;
    if (!messages || !Array.isArray(messages)) {
      return res.status(400).json({ error: '缺少 messages 参数' });
    }

    const payload = {
      model: model || 'gpt-4o-mini',
      messages,
      temperature: temperature ?? 0.7,
      max_tokens: max_tokens || 4096,
      stream: stream || false,
      ...rest
    };

    const url = `${LLM_BASE_URL}/v1/chat/completions`;
    console.log(`🤖 LLM Chat 请求: model=${payload.model}, messages=${messages.length}条`);

    if (payload.stream) {
      // 流式响应
      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${LLM_API_KEY}`
        },
        body: JSON.stringify(payload)
      });

      if (!response.ok) {
        const errText = await response.text();
        console.error('🤖 LLM Stream 错误:', response.status, errText);
        return res.status(response.status).json({ error: errText });
      }

      res.setHeader('Content-Type', 'text/event-stream');
      res.setHeader('Cache-Control', 'no-cache');
      res.setHeader('Connection', 'keep-alive');

      const reader = response.body;
      reader.on('data', (chunk) => res.write(chunk));
      reader.on('end', () => res.end());
      reader.on('error', (err) => {
        console.error('🤖 LLM Stream 读取错误:', err.message);
        res.end();
      });
    } else {
      // 非流式响应
      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${LLM_API_KEY}`
        },
        body: JSON.stringify(payload)
      });

      const data = await response.json();
      if (!response.ok) {
        console.error('🤖 LLM Chat 错误:', response.status, data);
        return res.status(response.status).json(data);
      }

      console.log(`🤖 LLM Chat 完成: tokens=${data?.usage?.total_tokens || '?'}`);
      res.json(data);
    }
  } catch (err) {
    console.error('🤖 LLM Chat 异常:', err.message);
    res.status(500).json({ error: `LLM 请求失败: ${err.message}` });
  }
});

// POST /api/llm/gemini — Gemini 原生格式代理（支持媒体识别）
app.post('/api/llm/gemini', async (req, res) => {
  try {
    const { model, contents, generationConfig, safetySettings, systemInstruction } = req.body;
    if (!contents) {
      return res.status(400).json({ error: '缺少 contents 参数' });
    }

    const geminiModel = model || 'gemini-2.5-flash';
    const url = `${LLM_BASE_URL}/v1beta/models/${geminiModel}:generateContent`;

    const payload = { contents };
    if (generationConfig) payload.generationConfig = generationConfig;
    if (safetySettings) payload.safetySettings = safetySettings;
    if (systemInstruction) payload.systemInstruction = systemInstruction;

    console.log(`🤖 Gemini 请求: model=${geminiModel}, parts=${contents?.[0]?.parts?.length || 0}`);

    const response = await fetch(url, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Authorization': `Bearer ${LLM_API_KEY}`
      },
      body: JSON.stringify(payload)
    });

    const data = await response.json();
    if (!response.ok) {
      console.error('🤖 Gemini 错误:', response.status, data);
      return res.status(response.status).json(data);
    }

    console.log(`🤖 Gemini 完成: tokens=${data?.usageMetadata?.totalTokenCount || '?'}`);
    res.json(data);
  } catch (err) {
    console.error('🤖 Gemini 异常:', err.message);
    res.status(500).json({ error: `Gemini 请求失败: ${err.message}` });
  }
});

// ==================== 健康检查 ====================

app.get('/api/health', (req, res) => {
  res.json({
    status: 'ok',
    timestamp: new Date().toISOString(),
    project: PROJECT_ROOT,
    services: {
      manifest: fs.existsSync(MANIFEST_PATH),
      whisperDir: fs.existsSync(WHISPER_DIR),
      videoDir: fs.existsSync(DATA_VIDEO_DIR) || fs.existsSync(LEGACY_VIDEO_DIR)
    }
  });
});

// ==================== 启动 ====================

app.listen(PORT, () => {
  console.log('');
  console.log('========================================');
  console.log(`  🚀 后端服务已启动: http://localhost:${PORT}`);
  console.log(`  📁 项目根目录: ${PROJECT_ROOT}`);
  console.log(`  📋 接口列表:`);
  console.log(`     GET  /api/health              — 健康检查`);
  console.log(`     GET  /api/whisper/status       — Whisper 可用性`);
  console.log(`     POST /api/whisper/transcribe   — 语音转文字`);
  console.log(`     GET  /api/manifest             — 获取视频清单`);
  console.log(`     PUT  /api/manifest/:videoId    — 更新视频信息`);
  console.log(`     POST /api/manifest             — 添加视频条目`);
  console.log(`     GET  /api/files/whisper/:id    — Whisper 输出文件`);
  console.log(`     GET  /api/files/read?path=     — 读取项目文件`);
  console.log(`     POST /api/upload/video         — 上传视频文件`);
  console.log(`     POST /api/remix/extract-audio  — 提取视频音频`);
  console.log(`     POST /api/remix/upload-asset   — 上传重塑素材到 Parse`);
  console.log(`     POST /api/download/video       — 下载远程视频到本地库`);
  console.log(`     GET  /api/download/video/:id   — 查询下载任务进度`);
  console.log(`     ---`);
  console.log(`     GET  /api/tasks               — 获取任务列表`);
  console.log(`     POST /api/tasks               — 创建任务`);
  console.log(`     PUT  /api/tasks/:id            — 更新任务`);
  console.log(`     DEL  /api/tasks/:id            — 删除任务`);
  console.log(`     ---`);
  console.log(`     GET  /api/history              — 获取历史记录`);
  console.log(`     POST /api/history              — 添加历史`);
  console.log(`     DEL  /api/history/:id           — 删除历史`);
  console.log(`     DEL  /api/history               — 清空历史`);
  console.log(`     ---`);
  console.log(`     GET  /api/results              — 获取结果`);
  console.log(`     POST /api/results              — 添加结果`);
  console.log(`     PUT  /api/results/:id          — 更新结果`);
  console.log(`     DEL  /api/results/:id           — 删除结果`);
  console.log(`     ---`);
  console.log(`     POST /api/llm/chat             — LLM 对话（OpenAI格式）`);
  console.log(`     POST /api/llm/gemini           — Gemini 媒体识别`);
  console.log('========================================');
  console.log('');
});