const http = require('http');
// generate-meet.js

// 1. CONFIGURATION - Paste your keys here
const CLIENT_ID = '977481853112-pdqmfvqcgnnuqbrbi88r84mgv14mqbq8.apps.googleusercontent.com';
const CLIENT_SECRET = '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';
const REFRESH_TOKEN = '1//04hBu9T1sojSVCgYIARAAGAQSNwF-L9IrXYktOSabjSSDtaBVKW3xRaqYKhp3x7brpaMAvcBK5rNNj2cQQMTuk0_HTkQWnJ2maLo';

const PORT = process.argv[2] || process.env.PORT || 3000;

// access token: ya29.a0AT3oNZ_5YKJidHRWMmuU7hvgcbXyNH6xttPtx2eMj0pBXPbeElKdOVOBEblX9-oVAcIjBxPlZF3yfm56lakEfu4guLDxGX4oPUxUnArEje425vee0ZvyV9ZObIvCrVhht5wD9lsR7cmg78JUE10dvfY2J9ebWZluwEMSChtIY4tk5FdyGa8sKqXyD0yTRheuYIOkR5kaCgYKAb4SARQSFQHGX2MiT1ih_xx7ZmodLXopYQ3zsw0206
/**
 * Step 1: Silently exchange the permanent Refresh Token for a temporary 1-hour Access Token
 */
async function getAccessToken() {
    const response = await fetch('https://oauth2.googleapis.com/token', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
            client_id: CLIENT_ID,
            client_secret: CLIENT_SECRET,
            refresh_token: REFRESH_TOKEN,
            grant_type: 'refresh_token'
        })
    });
    
    const data = await response.json();
    if (!response.ok) {
        throw new Error(`Token Refresh Failed: ${data.error_description || data.error}`);
    }
    return data.access_token;
}

/**
 * Step 2: Use the Access Token to create an OPEN meeting space (no knocking required)
 */
async function createOpenMeetSpace(accessToken) {
    const response = await fetch('https://meet.googleapis.com/v2/spaces', {
        method: 'POST',
        headers: {
            'Authorization': `Bearer ${accessToken}`,
            'Content-Type': 'application/json'
        },
        // "accessType: OPEN" makes sure anyone clicking this link enters instantly without waiting in a lobby
        body: JSON.stringify({
            config: {
                accessType: "OPEN" 
            }
        })
    });
    
    const data = await response.json();
    if (!response.ok) {
        throw new Error(`Meet API Error: ${data.error.message}`);
    }
    return data.meetingUri;
}

// 3. HTTP SERVER SETUP
const server = http.createServer(async (req, res) => {
    // Enable CORS headers so your frontend script can call this server
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type');

    // Handle browser CORS preflight check
    if (req.method === 'OPTIONS') {
        res.writeHead(200);
        res.end();
        return;
    }

    // Server endpoint matching /webhook/new-meet
    if (req.url === '/webhook/new-meet' || req.url === '/generate-meet') {
        try {
            console.log(`[${new Date().toISOString()}] 🔄 Connecting to Google Cloud...`);
            const accessToken = await getAccessToken();
            
            console.log(`[${new Date().toISOString()}] 🚀 Creating open Google Meet room...`);
            const meetLink = await createOpenMeetSpace(accessToken);

            console.log(`[${new Date().toISOString()}] 🎉 Link generated: ${meetLink}`);

            // Return JSON payload to the frontend
            res.writeHead(200, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({
                success: true,
                meetLink: meetLink
            }));

        } catch (error) {
            console.error(`[${new Date().toISOString()}] ❌ Error:`, error.message);

            res.writeHead(500, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({
                success: false,
                error: error.message
            }));
        }
    } else {
        res.writeHead(404, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ error: 'Endpoint not found' }));
    }
});

// Start listening
server.listen(PORT, () => {
    console.log(`=========================================`);
    console.log(`🚀 Server running at http://localhost:${PORT}`);
    console.log(`👉 Endpoint: http://localhost:${PORT}/webhook/new-meet`);
    console.log(`=========================================`);
});