Audio Separation Callbacks

const express = require('express');
const fs = require('fs');
const https = require('https');
const app = express();

app.use(express.json());

app.post('/vocal-separation-callback', (req, res) => {
  const { code, msg, data } = req.body;
  
  console.log('Received vocal separation callback:', {
    taskId: data.task_id,
    status: code,
    message: msg
  });
  
  if (code === 200 && data.vocal_removal_info) {
    // Vocal separation successful
    const vocalInfo = data.vocal_removal_info;
    console.log('Vocal separation completed successfully');
    
    // Determine separation type and download corresponding files
    let audioTypes = [];
    
    if (vocalInfo.instrumental_url) {
      // separate_vocal type
      audioTypes = [
        { name: 'original', url: vocalInfo.origin_url },
        { name: 'vocal', url: vocalInfo.vocal_url },
        { name: 'instrumental', url: vocalInfo.instrumental_url }
      ];
    } else {
      // split_stem type
      audioTypes = [
        { name: 'original', url: vocalInfo.origin_url },
        { name: 'vocal', url: vocalInfo.vocal_url },
        { name: 'backing_vocals', url: vocalInfo.backing_vocals_url },
        { name: 'drums', url: vocalInfo.drums_url },
        { name: 'bass', url: vocalInfo.bass_url },
        { name: 'guitar', url: vocalInfo.guitar_url },
        { name: 'keyboard', url: vocalInfo.keyboard_url },
        { name: 'percussion', url: vocalInfo.percussion_url },
        { name: 'strings', url: vocalInfo.strings_url },
        { name: 'synth', url: vocalInfo.synth_url },
        { name: 'fx', url: vocalInfo.fx_url },
        { name: 'brass', url: vocalInfo.brass_url },
        { name: 'woodwinds', url: vocalInfo.woodwinds_url }
      ];
    }
    
    // Download all separated audio files
    audioTypes.forEach(audio => {
      if (audio.url) {
        const filename = `${data.task_id}_${audio.name}.mp3`;
        const file = fs.createWriteStream(filename);
        
        https.get(audio.url, (response) => {
          response.pipe(file);
          
          file.on('finish', () => {
            file.close();
            console.log(`${audio.name} audio downloaded as ${filename}`);
          });
        }).on('error', (err) => {
          console.error(`${audio.name} audio download failed:`, err.message);
        });
      }
    });
    
  } else {
    // Task failed
    console.log('Vocal separation failed:', msg);
    
    // Handle failure cases...
    if (code === 400) {
      console.log('Invalid source audio or parameter error');
    } else if (code === 429) {
      console.log('Insufficient credits');
    } else if (code === 500) {
      console.log('Server internal error');
    }
  }
  
  // Return 200 status code to confirm callback received
  res.status(200).json({ status: 'received' });
});

app.listen(3000, () => {
  console.log('Vocal separation callback server running on port 3000');
});