/**
 * RTSP to WebSocket Proxy Server
 * Convert RTSP stream ke WebSocket untuk jsmpeg player
 * 
 * Usage:
 *   node rtsp-websocket-proxy.js <rtsp_url> <ws_port>
 * 
 * Example:
 *   node rtsp-websocket-proxy.js rtsp://10.60.0.10:8554/cam1 8082
 */

const WebSocket = require('ws');
const { spawn } = require('child_process');

// Parse arguments
const rtspUrl = process.argv[2] || 'rtsp://10.60.0.10:8554/cam1';
const wsPort = parseInt(process.argv[3]) || 8082;

console.log('🚀 Starting RTSP to WebSocket Proxy');
console.log('📹 RTSP URL:', rtspUrl);
console.log('🔌 WebSocket Port:', wsPort);
console.log('');

// Create WebSocket server
const wss = new WebSocket.Server({ 
    port: wsPort,
    perMessageDeflate: false 
});

let ffmpegProcess = null;
let clients = new Set();

wss.on('connection', (ws) => {
    console.log('✅ New WebSocket client connected');
    clients.add(ws);
    
    // Start FFmpeg process jika belum ada
    if (!ffmpegProcess) {
        startFFmpeg();
    }
    
    ws.on('close', () => {
        console.log('❌ WebSocket client disconnected');
        clients.delete(ws);
        
        // Stop FFmpeg jika tidak ada client lagi
        if (clients.size === 0 && ffmpegProcess) {
            console.log('⏹️ No clients, stopping FFmpeg');
            stopFFmpeg();
        }
    });
    
    ws.on('error', (error) => {
        console.error('❌ WebSocket error:', error.message);
    });
});

function startFFmpeg() {
    console.log('🎬 Starting FFmpeg process...');
    
    // FFmpeg command untuk convert RTSP ke MPEG1 video stream
    // Format: MPEG1 video (untuk jsmpeg) dengan resolusi 800x600, bitrate 1000k
    const ffmpegArgs = [
        '-i', rtspUrl,                    // Input RTSP URL
        '-f', 'mpegts',                   // Output format: MPEG Transport Stream
        '-codec:v', 'mpeg1video',         // Video codec: MPEG1 (untuk jsmpeg)
        '-s', '800x600',                  // Resolution
        '-b:v', '1000k',                  // Video bitrate
        '-bf', '0',                       // No B-frames
        '-codec:a', 'mp2',                // Audio codec: MP2
        '-b:a', '128k',                   // Audio bitrate
        '-r', '25',                       // Frame rate: 25 fps
        'pipe:1'                          // Output to stdout
    ];
    
    ffmpegProcess = spawn('ffmpeg', ffmpegArgs, {
        stdio: ['ignore', 'pipe', 'pipe']
    });
    
    ffmpegProcess.stdout.on('data', (data) => {
        // Broadcast ke semua connected clients
        clients.forEach(client => {
            if (client.readyState === WebSocket.OPEN) {
                try {
                    client.send(data);
                } catch (error) {
                    console.error('Error sending data to client:', error.message);
                }
            }
        });
    });
    
    ffmpegProcess.stderr.on('data', (data) => {
        // FFmpeg logs ke stderr, bisa di-ignore atau di-log untuk debugging
        const message = data.toString();
        if (message.includes('error') || message.includes('Error')) {
            console.error('FFmpeg error:', message);
        }
    });
    
    ffmpegProcess.on('exit', (code, signal) => {
        console.log(`⚠️ FFmpeg process exited with code ${code}, signal ${signal}`);
        ffmpegProcess = null;
        
        // Restart jika masih ada clients
        if (clients.size > 0) {
            console.log('🔄 Restarting FFmpeg...');
            setTimeout(() => startFFmpeg(), 2000);
        }
    });
    
    ffmpegProcess.on('error', (error) => {
        console.error('❌ FFmpeg spawn error:', error.message);
        console.error('💡 Make sure FFmpeg is installed and available in PATH');
        ffmpegProcess = null;
    });
    
    console.log('✅ FFmpeg process started');
}

function stopFFmpeg() {
    if (ffmpegProcess) {
        console.log('⏹️ Stopping FFmpeg process...');
        ffmpegProcess.kill('SIGTERM');
        ffmpegProcess = null;
    }
}

// Graceful shutdown
process.on('SIGINT', () => {
    console.log('\n🛑 Shutting down...');
    stopFFmpeg();
    wss.close(() => {
        console.log('✅ Server closed');
        process.exit(0);
    });
});

process.on('SIGTERM', () => {
    console.log('\n🛑 Shutting down...');
    stopFFmpeg();
    wss.close(() => {
        console.log('✅ Server closed');
        process.exit(0);
    });
});

console.log(`✅ WebSocket server listening on ws://0.0.0.0:${wsPort}`);
console.log('💡 Connect from browser: ws://localhost:' + wsPort);
console.log('💡 Press Ctrl+C to stop\n');