Veo3 Video Generation Callbacks

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

app.use(express.json());

app.post('/veo3-callback', (req, res) => {
  const { code, msg, data } = req.body;
  
  console.log('Received Veo3 video generation callback:', {
    taskId: data.taskId,
    status: code,
    message: msg
  });
  
  if (code === 200) {
    // Video generation successful
    const { taskId, info, fallbackFlag } = data;
    const { resultUrls, originUrls, resolution } = info;
    
    console.log('Video generation successful!');
    console.log(`Task ID: ${taskId}`);
    console.log(`Generated video URLs: ${resultUrls}`);
    console.log(`Video resolution: ${resolution}`);
    console.log(`Using fallback model: ${fallbackFlag ? 'Yes' : 'No'}`);
    if (originUrls) {
      console.log(`Original video URLs: ${originUrls}`);
    }
    
    // Download generated video files
    resultUrls.forEach((url, index) => {
      if (url) {
        downloadFile(url, `veo3_generated_${taskId}_${index}.mp4`)
          .then(() => console.log(`Video ${index + 1} downloaded successfully`))
          .catch(err => console.error(`Video ${index + 1} download failed:`, err));
      }
    });
    
    // Download original video files (if exists)
    if (originUrls) {
      originUrls.forEach((url, index) => {
        if (url) {
          downloadFile(url, `veo3_original_${taskId}_${index}.mp4`)
            .then(() => console.log(`Original video ${index + 1} downloaded successfully`))
            .catch(err => console.error(`Original video ${index + 1} download failed:`, err));
        }
      });
    }
    
  } else {
    // Video generation failed
    console.log('Veo3 video generation failed:', msg);
    
    // Handle specific error types
    if (code === 400) {
      console.log('Client error - Check prompts and content policies');
    } else if (code === 422) {
      console.log('Fallback failed - Consider enabling fallback functionality (enableFallback: true)');
    } else if (code === 500) {
      console.log('Server internal error - Please try again later');
    } else if (code === 501) {
      console.log('Task failed - Video generation failed');
    }
  }
  
  // Return 200 status code to confirm callback received
  res.status(200).json({ code: 200, msg: 'success' });
});

// Helper function: Download file
function downloadFile(url, filename) {
  return new Promise((resolve, reject) => {
    const file = fs.createWriteStream(filename);
    
    https.get(url, (response) => {
      if (response.statusCode === 200) {
        response.pipe(file);
        file.on('finish', () => {
          file.close();
          resolve();
        });
      } else {
        reject(new Error(`HTTP ${response.statusCode}`));
      }
    }).on('error', reject);
  });
}

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