WebRTC

// Caller creates offer
const offer = await peerConnection.createOffer();
await peerConnection.setLocalDescription(offer);

// Send offer via signaling server
signalingSocket.send(JSON.stringify({
  type: 'offer',
  sdp: offer
}));

// Callee receives offer, creates answer
await peerConnection.setRemoteDescription(offer);
const answer = await peerConnection.createAnswer();
await peerConnection.setLocalDescription(answer);

// Send answer back
signalingSocket.send(JSON.stringify({
  type: 'answer',
  sdp: answer
}));

class VideoCall {
  constructor(signalingSocket) {
    this.socket = signalingSocket;
    this.peerConnection = new RTCPeerConnection({
      iceServers: [
        { urls: 'stun:stun.l.google.com:19302' },
        {
          urls: 'turn:turn.example.com:3478',
          username: 'user',
          credential: 'pass'
        }
      ]
    });
    this.setupEventHandlers();
  }

  async startCall() {
    // Get user media
    const stream = await navigator.mediaDevices.getUserMedia({
      video: { width: 1280, height: 720 },
      audio: true
    });

    // Add tracks to peer connection
    stream.getTracks().forEach(track => {
      this.peerConnection.addTrack(track, stream);
    });

    // Create and send offer
    const offer = await this.peerConnection.createOffer();
    await this.peerConnection.setLocalDescription(offer);
    this.socket.send(JSON.stringify({ type: 'offer', offer }));
  }

  setupEventHandlers() {
    // Handle ICE candidates
    this.peerConnection.onicecandidate = (event) => {
      if (event.candidate) {
        this.socket.send(JSON.stringify({
          type: 'ice-candidate',
          candidate: event.candidate
        }));
      }
    };

    // Handle remote stream
    this.peerConnection.ontrack = (event) => {
      const remoteVideo = document.getElementById('remoteVideo');
      remoteVideo.srcObject = event.streams[0];
    };

    // Handle connection state
    this.peerConnection.onconnectionstatechange = () => {
      console.log('Connection state:', this.peerConnection.connectionState);
    };
  }
}

// Create data channel
const dataChannel = peerConnection.createDataChannel('messages', {
  ordered: true,
  maxRetransmits: 3
});

dataChannel.onopen = () => {
  console.log('Data channel opened');
  dataChannel.send('Hello from peer!');
};

dataChannel.onmessage = (event) => {
  console.log('Received:', event.data);
};

// Handle incoming data channel
peerConnection.ondatachannel = (event) => {
  const channel = event.channel;
  channel.onmessage = (event) => {
    console.log('Data received:', event.data);
  };
};