// Production
const client = new TelnyxRTC({ login_token: jwt });

// Development only
const client = new TelnyxRTC({ login: 'user', password: 'pass' });

// Backend generates token — API key never reaches the browser
app.post('/api/telnyx-token', async (req, res) => {
 const token = await telnyx.telephonyCredentials.createToken(credentialId);
 res.json({ token });
});

// Never do this — API key in browser source
const response = await fetch('https://api.telnyx.com/v2/telnyx_rtc/access_tokens', {
 headers: { Authorization: `Bearer ${API_KEY}` }, // API_KEY exposed!
});

client.on('telnyx.notification', (notification) => {
 if (notification.type === 'userMediaError') return;

 // Check for token expiring soon
 if (notification.type === 'callUpdate' && notification.call?.state === 'destroyed') {
 // If disconnected due to auth, try refresh
 }
});

// Or use the session event
client.on('telnyx.ready', () => {
 console.log('Connected and authenticated');
});

// Create once
let client = null;

function getClient() {
 if (!client) {
 client = new TelnyxRTC({ login_token: getJwt() });
 client.connect();
 }
 return client;
}

// Creating multiple instances
const client1 = new TelnyxRTC({ login_token: jwt }); // WebSocket 1
const client2 = new TelnyxRTC({ login_token: jwt }); // WebSocket 2 — wasteful

window.addEventListener('beforeunload', () => {
 if (client) {
 client.calls.forEach(call => call.hangup());
 client.disconnect();
 }
});

client.on('telnyx.notification', (notification) => {
 if (notification.type === 'callUpdate') {
 const call = notification.call;
 if (call.state === 'reconnecting') {
 showBanner('Connection lost. Reconnecting...');
 } else if (call.state === 'active' && wasReconnecting) {
 hideBanner();
 }
 }
});

const call = client.newCall({
 destinationNumber: '+12345678900',
 audio: true,
 // SDK handles getUserMedia internally
});

const stream = await navigator.mediaDevices.getUserMedia({
 audio: {
 echoCancellation: true,
 noiseSuppression: true,
 autoGainControl: true,
 },
});

const client = new TelnyxRTC({
 login_token: jwt,
 enableCallReports: true,
 callReportInterval: 5000,
});

client.on('telnyx.notification', (notification) => {
 if (notification.type === 'callQuality') {
 const { mos, rtt, jitter, packetLoss } = notification.callQuality;
 if (mos < 3.0 || rtt > 500 || jitter > 100 || packetLoss > 5) {
 logQualityIssue(notification);
 }
 }
});

// Only if you have a specific security requirement
const client = new TelnyxRTC({
 login_token: jwt,
 forceRelayCandidate: true, // Forces all media through TURN
});

// Default — lets ICE find the best path
const client = new TelnyxRTC({
 login_token: jwt,
});

client.on('telnyx.notification', (notification) => {
 if (notification.type === 'userMediaError') {
 const { code, message } = notification.error;

 switch (code) {
 case 1: // Not allowed
 showError('Microphone access denied. Please allow access in browser settings.');
 break;
 case 2: // Not found
 showError('No microphone detected. Please connect a microphone.');
 break;
 case 3: // Not readable
 showError('Microphone in use by another application.');
 break;
 }
 }
});

client.on('telnyx.socket.close', () => {
 showError('Connection to Telnyx lost. Attempting to reconnect...');
});

client.on('telnyx.socket.error', (error) => {
 logError('WebSocket error', error);
});

// Technical error exposed to user
showError(`Call failed: ${error.message}`);

// User-friendly message
showError('Unable to connect the call. Please try again.');

client.on('telnyx.notification', (notification) => {
 if (notification.call?.state === 'destroyed') {
 // Remove call from your state
 removeCallFromState(notification.call.id);
 }
});

// When component unmounts (React example)
useEffect(() => {
 const handler = (notification) => { /* ... */ };
 client.on('telnyx.notification', handler);

 return () => {
 client.off('telnyx.notification', handler);
 };
}, []);

const client = new TelnyxRTC({
 login_token: jwt,
 enableCallReports: true, // Auto-upload reports after each call
 callReportInterval: 5000, // Stats every 5 seconds
});

client.on('telnyx.notification', (notification) => {
 if (notification.type === 'callQuality') {
 sendToMonitoring({
 callId: notification.call.id,
 mos: notification.callQuality.mos,
 timestamp: Date.now(),
 });
 }
});