initial commit

src/lib/webrtc.ts

@@ -0,0 +1,186 @@
+import { get } from 'svelte/store';
+import { ws } from '../stores/websocketStore';
+
+interface WebRTCPeerCallbacks {
+    onConnected: () => void;
+    onMessage: (message: string | ArrayBuffer) => void;
+    onDataChannelOpen: () => void;
+    onNegotiationNeeded: () => void;
+    onError: (error: any) => void;
+}
+
+export class WebRTCPeer {
+    private peer: RTCPeerConnection | null = null;
+    private dataChannel: RTCDataChannel | null = null;
+    private isInitiator: boolean;
+    private roomId: string;
+    private callbacks: WebRTCPeerCallbacks;
+
+    private iceServers = [
+        { urls: 'stun:stun.l.google.com:19302' },
+        { urls: 'stun:stun1.l.google.com:19302' },
+    ];
+
+    constructor(roomId: string, isInitiator: boolean, callbacks: WebRTCPeerCallbacks) {
+        this.roomId = roomId;
+        this.isInitiator = isInitiator;
+        this.callbacks = callbacks;
+    }
+
+    private sendIceCandidate(candidate: RTCIceCandidate) {
+        get(ws).send(JSON.stringify({
+            type: 'ice-candidate',
+            data: {
+                roomId: this.roomId,
+                candidate: candidate,
+            },
+        }))
+    }
+
+    public async initialize() {
+        // dont initialize twice
+        if (this.peer) return;
+
+        this.peer = new RTCPeerConnection({
+            iceServers: this.iceServers,
+        });
+
+        // 1. Initialize ICE candidates
+        this.peer.onicecandidate = (event) => {
+            if (event.candidate) {
+                this.sendIceCandidate(event.candidate);
+            }
+        }
+
+        this.peer.oniceconnectionstatechange = () => {
+            console.log('ICE connection state changed to:', this.peer?.iceConnectionState);
+            if (this.peer?.iceConnectionState === 'connected' || this.peer?.iceConnectionState === 'completed') {
+                this.callbacks.onConnected();
+            } else if (this.peer?.iceConnectionState === 'failed') {
+                this.callbacks.onError('ICE connection failed');
+            }
+        };
+
+        this.peer.onnegotiationneeded = () => {
+            this.callbacks.onNegotiationNeeded();
+        };
+
+        // 2. Create data channel
+        if (this.isInitiator) {
+            this.dataChannel = this.peer.createDataChannel('data-channel');
+            this.setupDataChannelEvents(this.dataChannel);
+            console.log('created data channel');
+        } else {
+            this.peer.ondatachannel = (event) => {
+                this.dataChannel = event.channel;
+                this.setupDataChannelEvents(this.dataChannel);
+                console.log('received data channel');
+            };
+        }
+    }
+
+    private setupDataChannelEvents(channel: RTCDataChannel) {
+        channel.onopen = () => {
+            console.log('data channel open');
+            this.callbacks.onDataChannelOpen();
+        };
+
+        channel.onmessage = (event) => {
+            console.log('data channel message:', event.data);
+            this.callbacks.onMessage(event.data);
+        };
+
+        channel.onclose = () => {
+            console.log('data channel closed');
+        };
+
+        channel.onerror = (error) => {
+            console.error('data channel error:', error);
+            this.callbacks.onError(error);
+        };
+    }
+
+    // SDP exchange
+    public async createOffer() {
+        if (!this.peer) throw new Error('Peer not initialized');
+
+        try {
+            const offer = await this.peer.createOffer();
+            await this.peer.setLocalDescription(offer);
+
+            get(ws).send(JSON.stringify({
+                type: 'offer',
+                data: {
+                    roomId: this.roomId,
+                    sdp: offer,
+                },
+            }));
+
+        } catch (error) {
+            console.error('Error creating offer:', error);
+            this.callbacks.onError(error);
+        }
+    }
+
+    // both peers call this to set the remote SDP
+    public async setRemoteDescription(sdp: RTCSessionDescriptionInit) {
+        if (!this.peer) throw new Error('Peer not initialized');
+
+        try {
+            await this.peer.setRemoteDescription(sdp);
+        } catch (error) {
+            console.error('Error setting remote description:', error);
+            this.callbacks.onError(error);
+        }
+    }
+
+    public async createAnswer() {
+        if (!this.peer) throw new Error('Peer not initialized');
+
+        try {
+            const answer = await this.peer.createAnswer();
+            await this.peer.setLocalDescription(answer);
+
+            get(ws).send(JSON.stringify({
+                type: 'answer',
+                data: {
+                    roomId: this.roomId,
+                    sdp: answer,
+                },
+            }));
+
+        } catch (error) {
+            console.error('Error creating answer:', error);
+            this.callbacks.onError(error);
+        }
+    }
+
+    public async addIceCandidate(candidate: RTCIceCandidateInit) {
+        if (!this.peer) throw new Error('Peer not initialized');
+
+        try {
+            await this.peer.addIceCandidate(new RTCIceCandidate(candidate));
+        } catch (error) {
+            console.error('Error adding ICE candidate:', error);
+            this.callbacks.onError(error);
+        }
+    }
+
+    public send(data: string | ArrayBuffer) {
+        if (!this.dataChannel || this.dataChannel.readyState !== 'open') throw new Error('Data channel not initialized');
+        this.dataChannel.send(data);
+    }
+
+    public close() {
+        if (this.dataChannel) {
+            this.dataChannel.close();
+        }
+
+        if (this.peer) {
+            this.peer.close();
+        }
+
+        this.peer = null;
+        this.dataChannel = null;
+    }
+}