const fs = require('fs');
const ytdl = require('ytdl-core-enhanced');

// Download a video
ytdl('https://www.youtube.com/watch?v=dQw4w9WgXcQ')
  .pipe(fs.createWriteStream('video.mp4'));

const ytdl = require('ytdl-core-enhanced');
const fs = require('fs');

// Simple download
ytdl('https://youtu.be/dQw4w9WgXcQ', { quality: 'highest' })
  .pipe(fs.createWriteStream('my-video.mp4'));

// Audio only download
ytdl('https://youtu.be/dQw4w9WgXcQ', { filter: 'audioonly' })
  .pipe(fs.createWriteStream('my-audio.mp3'));

// Get video information
const info = await ytdl.getInfo('https://youtu.be/dQw4w9WgXcQ');
console.log('Title:', info.videoDetails.title);
console.log('Duration:', info.videoDetails.lengthSeconds);

const stream = ytdl('https://youtu.be/dQw4w9WgXcQ');

stream.on('progress', (chunkLength, downloaded, total) => {
  const percent = (downloaded / total * 100).toFixed(2);
  console.log(`Downloaded: ${percent}%`);
});

stream.pipe(fs.createWriteStream('video.mp4'));

// Specific quality
ytdl(url, { quality: '720p' })

// Highest quality
ytdl(url, { quality: 'highest' })

// Lowest quality (fastest download)
ytdl(url, { quality: 'lowest' })

// Custom filter
ytdl(url, { 
  filter: format => format.container === 'mp4' && format.hasVideo 
})

// Enable fast Android client (default: true)
const info = await ytdl.getInfo(url, { fastMode: true });

// Disable fast mode to use standard method
const info = await ytdl.getInfo(url, { fastMode: false });

// Disable DisTube fallback if needed
const stream = ytdl(url, { disableDistubeFallback: true });

// Download specific byte range
ytdl(url, { 
  range: { start: 0, end: 1024 * 1024 } // First 1MB
})

// Use IPv6 block for download
ytdl(url, { 
  IPv6Block: '2001:db8::/32' 
})

// Basic cookie usage for authentication
const info = await ytdl.getInfo(url, {
  requestOptions: {
    headers: {
      Cookie: 'VISITOR_INFO1_LIVE=xyz; CONSENT=YES+cb'
    }
  }
});

// Age-restricted videos with cookies
const stream = ytdl(url, {
  quality: 'highest',
  requestOptions: {
    headers: {
      Cookie: 'VISITOR_INFO1_LIVE=abc; SESSION_TOKEN=def; CONSENT=YES+cb'
    }
  }
});

// Extract cookies from browser (manual)
// 1. Open YouTube in browser
// 2. F12 -> Application/Storage -> Cookies -> youtube.com
// 3. Copy VISITOR_INFO1_LIVE and other relevant cookies

const express = require('express');
const ytdl = require('ytdl-core-enhanced');
const app = express();

app.get('/download', async (req, res) => {
  const { url } = req.query;
  
  if (!ytdl.validateURL(url)) {
    return res.status(400).send('Invalid YouTube URL');
  }

  try {
    const info = await ytdl.getInfo(url);
    res.header('Content-Disposition', `attachment; filename="${info.videoDetails.title}.mp4"`);
    
    ytdl(url, { quality: 'highest' }).pipe(res);
  } catch (error) {
    res.status(500).send('Download failed');
  }
});

const ytdl = require('ytdl-core-enhanced');

try {
  const stream = ytdl('https://youtu.be/dQw4w9WgXcQ');
  
  stream.on('error', (error) => {
    console.error('Download error:', error.message);
    // Automatic fallback will be attempted
  });
  
  stream.on('info', (info, format) => {
    console.log('Using format:', format.qualityLabel);
  });
  
} catch (error) {
  console.error('Setup error:', error.message);
}

// Download specific audio format (140 = 128kbps AAC)
const stream = ytdl(url, { format: { itag: 140 } });

// Download specific video format (298 = 720p MP4)
const stream = ytdl(url, { format: { itag: 298 } });

// Audio only formats
const audioFormats = info.formats.filter(format => 
  format.hasAudio && !format.hasVideo
);

// Video only formats  
const videoFormats = info.formats.filter(format => 
  format.hasVideo && !format.hasAudio
);

// Combined audio+video formats
const combinedFormats = info.formats.filter(format => 
  format.hasAudio && format.hasVideo
);

// Highest quality video
const stream = ytdl(url, { quality: 'highest' });

// Lowest quality (fastest download)
const stream = ytdl(url, { quality: 'lowest' });

// Best audio quality
const stream = ytdl(url, { quality: 'highestaudio' });

// Lowest audio (bandwidth saving)
const stream = ytdl(url, { quality: 'lowestaudio' });

const info = await ytdl.getInfo(url);

// Print all available formats
info.formats.forEach(format => {
  console.log(`Format ${format.itag}:`);
  console.log(`  Quality: ${format.qualityLabel || 'Audio only'}`);
  console.log(`  Container: ${format.container}`);
  console.log(`  Size: ${format.contentLength ? 
    (format.contentLength / 1024 / 1024).toFixed(2) + 'MB' : 'Unknown'}`);
  console.log(`  Audio: ${format.hasAudio ? 
    format.audioBitrate + 'kbps' : 'No'}`);
  console.log(`  Video: ${format.hasVideo ? 
    format.qualityLabel : 'No'}`);
  console.log(`  URL: ${format.url}\n`);
});

// Categorize formats
console.log(`📀 Audio formats: ${audioFormats.length}`);
console.log(`🎬 Video formats: ${videoFormats.length}`);  
console.log(`🎭 Combined formats: ${combinedFormats.length}`);
console.log(`📊 Total formats: ${info.formats.length}`);

// 🎵 Music/Podcast Download (Best Quality Audio)
const musicStream = ytdl(url, { 
  filter: format => format.itag === 140 // 128kbps AAC
});

// 📱 Mobile Video (Balance Quality/Size)  
const mobileStream = ytdl(url, {
  filter: format => format.itag === 396 // 360p MP4
});

// 💻 Desktop Video (Good Quality)
const desktopStream = ytdl(url, {
  filter: format => format.itag === 298 // 720p MP4
});

// 📺 High Quality Video (Large File)
const hdStream = ytdl(url, {
  filter: format => format.itag === 299 // 1080p MP4
});

// ⚡ Fast Download (Small File)
const fastStream = ytdl(url, {
  filter: format => format.itag === 598 // 144p MP4
});

const fs = require('fs');
const ytdl = require('ytdl-core-enhanced');

// Tải video
ytdl('https://www.youtube.com/watch?v=dQw4w9WgXcQ')
  .pipe(fs.createWriteStream('video.mp4'));

const ytdl = require('ytdl-core-enhanced');
const fs = require('fs');

// Tải đơn giản
ytdl('https://youtu.be/dQw4w9WgXcQ', { quality: 'highest' })
  .pipe(fs.createWriteStream('video-cua-toi.mp4'));

// Chỉ tải âm thanh
ytdl('https://youtu.be/dQw4w9WgXcQ', { filter: 'audioonly' })
  .pipe(fs.createWriteStream('nhac-cua-toi.mp3'));

// Lấy thông tin video
const info = await ytdl.getInfo('https://youtu.be/dQw4w9WgXcQ');
console.log('Tiêu đề:', info.videoDetails.title);
console.log('Thời lượng:', info.videoDetails.lengthSeconds);

const stream = ytdl('https://youtu.be/dQw4w9WgXcQ');

stream.on('progress', (chunkLength, downloaded, total) => {
  const percent = (downloaded / total * 100).toFixed(2);
  console.log(`Đã tải: ${percent}%`);
});

stream.pipe(fs.createWriteStream('video.mp4'));

// Chất lượng cụ thể
ytdl(url, { quality: '720p' })

// Chất lượng cao nhất
ytdl(url, { quality: 'highest' })

// Chất lượng thấp nhất (tải nhanh nhất)
ytdl(url, { quality: 'lowest' })

// Bật client Android nhanh (mặc định: true)
const info = await ytdl.getInfo(url, { fastMode: true });

// Tắt chế độ nhanh
const info = await ytdl.getInfo(url, { fastMode: false });

// Sử dụng cookie cơ bản
const info = await ytdl.getInfo(url, {
  requestOptions: {
    headers: {
      Cookie: 'VISITOR_INFO1_LIVE=xyz; CONSENT=YES+cb'
    }
  }
});

// Video giới hạn độ tuổi với cookie
const stream = ytdl(url, {
  quality: 'highest',
  requestOptions: {
    headers: {
      Cookie: 'VISITOR_INFO1_LIVE=abc; SESSION_TOKEN=def'
    }
  }
});

// Cách lấy cookie từ trình duyệt:
// 1. Mở YouTube trên trình duyệt
// 2. F12 -> Application -> Cookies -> youtube.com  
// 3. Copy VISITOR_INFO1_LIVE và các cookie khác

try {
  const stream = ytdl('https://youtu.be/dQw4w9WgXcQ');
  
  stream.on('error', (error) => {
    console.error('Lỗi tải:', error.message);
    // Hệ thống sẽ tự động fallback
  });
  
  stream.on('info', (info, format) => {
    console.log('Đang dùng format:', format.qualityLabel);
  });
  
} catch (error) {
  console.error('Lỗi thiết lập:', error.message);
}