video-workflow/server/routes/video-composite.js

function registerVideoCompositeRoutes(app, deps) {
  const { fs, path, spawn, dataDir, removeFileIfExists } = deps;
  const compositeDir = path.join(dataDir, 'composite');
  if (!fs.existsSync(compositeDir)) fs.mkdirSync(compositeDir, { recursive: true });

  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;
  }

  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);
      });
    });
  }

  const getAudioDuration = getMediaDuration;

  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);
      });
    });
  }

  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'];

  function createSegmentVideo(imagePath, audioPath, 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,
          '-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);
      }
    });
  }

  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;
      }

      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);
      });
    });
  }

  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);
      });
    });
  }

  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);
      }
    });
  }

  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`);
    }

    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);

      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' };
      }
      await createVideoOnlySegment(videoPath, segVideoPath);
      return { path: segVideoPath, duration: null, mode: 'C' };
    }

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

  function concatVideos(segmentPaths, outputPath) {
    return new Promise((resolve, reject) => {
      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);
      });
    });
  }

  app.post('/api/video/composite', 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' });
    }

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

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

      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' });
      }

      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(compositeDir, finalFilename);

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

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

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

  app.post('/api/video/composite/stream', async (req, res) => {
    return res.status(410).json({
      error: 'deprecated: client now composes in browser via ffmpeg.wasm; see BrowserFfmpegService.composeVideo()',
    });
  });

  app.get('/api/video/composite/:filename', (req, res) => {
    const filePath = path.join(compositeDir, 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);
  });
}

module.exports = { registerVideoCompositeRoutes };