const call = client.newCall({
 destinationNumber: '+12345678900',
 audio: true,
});

// call.state === 'new'
// SDK is: gathering ICE candidates, preparing SDP, sending INVITE

// Remote party's phone is ringing
// call.state === 'ringing'

// Remote party answered
// call.state === 'active'

client.on('telnyx.notification', (notification) => {
 if (notification.type === 'callUpdate') {
 const call = notification.call;

 if (call.state === 'ringing' && call.direction === 'inbound') {
 // Incoming call!
 const from = call.remotePartyNumber;
 const to = call.remotePartyName;
 showIncomingCallUI({ from, to, call });
 }
 }
});

// User clicks "Accept"
call.answer();
// call.state → 'active'

// User clicks "Reject"
call.hangup();
// call.state → 'destroyed'

call.hold();
// call.state → 'held'

call.unhold();
// call.state → 'active'

// Network interruption during call
// call.state → 'reconnecting'

client.on('telnyx.notification', (notification) => {
 if (notification.call.state === 'destroyed') {
 const call = notification.call;
 console.log(`Call ended. Direction: ${call.direction}`);
 console.log(`Duration: ${call.duration}s`);
 console.log(`End reason: ${call.cause}`); // normal, hangup, timeout, error
 }
});

// WRONG — answering an already-active call
call.answer(); // First answer — starts PeerConnection
call.answer(); // Second answer — creates ANOTHER PeerConnection!

// Result: Two PeerConnections, the second one never connects properly
// SDK bug: CallReportCollector may track the wrong PC → reports show zero audio

let answered = false;

function answerCall(call) {
 if (answered || call.state !== 'ringing') return;
 answered = true;
 call.answer();
}

// WRONG — only checking for 'active'
if (call.state === 'active') {
 startTimer();
}
// What if the call goes to 'destroyed'? Timer keeps running forever.

// CORRECT — handle both
if (call.state === 'active') {
 startTimer();
} else if (call.state === 'destroyed') {
 stopTimer();
 cleanupCall(call);
}

// If you don't handle reconnecting, the user thinks the call dropped
// and tries to call again — creating a second call

// Show a banner so the user knows to wait
if (call.state === 'reconnecting') {
 showReconnectingBanner();
}