video-workflow/server/routes/audio-extraction.js

const fs = require('fs');
const path = require('path');
const { spawn } = require('child_process');

function registerAudioExtractionRoutes(app, deps) {
  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 = deps.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 = deps.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(deps.dataRemixAssetDir, outputFilename);
    const ffmpegArgs = ['-y', '-i', videoPath, '-vn', '-acodec', 'pcm_s16le', '-ar', '44100', '-ac', '2', outputPath];
    const proc = spawn('ffmpeg', ffmpegArgs, { cwd: deps.projectRoot });

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

    proc.on('error', (err) => {
      deps.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 });
    });

    proc.on('close', (code) => {
      if (code !== 0 || !fs.existsSync(outputPath)) {
        deps.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', () => {
        deps.removeFileIfExists(outputPath);
      });
      stream.on('error', () => {
        deps.removeFileIfExists(outputPath);
        if (!res.headersSent) {
          res.status(500).json({ error: '音频文件读取失败' });
        } else {
          res.end();
        }
      });
      stream.pipe(res);
    });
  });

  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 = deps.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 = deps.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-${Date.now()}`;
    const outputFilename = `${safeBaseName}-${Date.now()}.m4a`;
    const outputPath = path.join(deps.dataRemixAssetDir, outputFilename);
    const outputMimeType = 'audio/mp4';

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

    const ffmpegArgs = ['-y', '-i', videoPath, '-vn', '-c:a', 'aac', '-b:a', '64k', '-ar', '16000', '-ac', '1', outputPath];
    const proc = spawn('ffmpeg', ffmpegArgs, { cwd: deps.projectRoot });

    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) => {
      deps.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: ${tail}`);
        deps.removeFileIfExists(outputPath);
        const lastErrorLine = stderr.split('\n').filter(Boolean).slice(-1)[0] || '';
        return safeRespond(500, { error: `音频提取失败 (exit=${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)`);

      const audioBuffer = fs.readFileSync(outputPath);
      const audioBase64 = audioBuffer.toString('base64');
      deps.removeFileIfExists(outputPath);

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

module.exports = { registerAudioExtractionRoutes };