video_socket-server/client/public/call/media/server-recording-peer.js

import { createLogger } from '../../shared/logger.js';

const logger = createLogger('server-recording-peer');

export class ServerRecordingPeer {
    constructor({
        rtcConfiguration,
        getLocalStream,
        getSignaling,
        getConnectionId,
        getParticipantId
    }) {
        this.rtcConfiguration = rtcConfiguration;
        this.getLocalStream = getLocalStream;
        this.getSignaling = getSignaling;
        this.getConnectionId = getConnectionId;
        this.getParticipantId = getParticipantId;
        this.peers = new Map();
    }

    async start(request) {
        if (!request || !request.recordingId) {
            return;
        }

        this.stop(request.recordingId);

        const localStream = this.getLocalStream();
        const tracks = localStream ? localStream.getTracks().filter(track => track.readyState !== 'ended') : [];
        if (tracks.length === 0) {
            this._sendStatus(request, 'no-local-media');
            return;
        }

        const pc = new RTCPeerConnection(this.rtcConfiguration);
        const state = {
            pc,
            recordingId: request.recordingId,
            connectionId: request.connectionId || this.getConnectionId(),
            pendingCandidates: []
        };
        this.peers.set(request.recordingId, state);

        pc.onicecandidate = (event) => {
            if (!event.candidate) {
                return;
            }

            this._sendCandidate(state, event.candidate);
        };
        pc.onconnectionstatechange = () => {
            logger.debug(`recording peer ${request.recordingId} state: ${pc.connectionState}`);
        };

        tracks.forEach(track => {
            pc.addTransceiver(track, {
                direction: 'sendonly',
                streams: localStream ? [localStream] : []
            });
        });

        const offer = await pc.createOffer();
        await pc.setLocalDescription(offer);
        this._sendOffer(state);
    }

    async applyAnswer(answer) {
        const state = this.peers.get(answer?.recordingId);
        if (!state || !answer?.sdp) {
            return;
        }

        await state.pc.setRemoteDescription(new RTCSessionDescription({
            type: 'answer',
            sdp: answer.sdp
        }));
        await this._flushPendingCandidates(state);
    }

    async addIceCandidate(candidate) {
        const state = this.peers.get(candidate?.recordingId);
        if (!state || !candidate?.candidate) {
            return;
        }

        const iceCandidate = new RTCIceCandidate({
            candidate: candidate.candidate,
            sdpMid: candidate.sdpMid,
            sdpMLineIndex: candidate.sdpMLineIndex
        });

        if (!state.pc.remoteDescription) {
            state.pendingCandidates.push(iceCandidate);
            return;
        }

        await state.pc.addIceCandidate(iceCandidate);
    }

    stop(recordingId) {
        if (!recordingId) {
            this.peers.forEach(peerState => this._closePeer(peerState));
            this.peers.clear();
            return;
        }

        const state = this.peers.get(recordingId);
        if (!state) {
            return;
        }

        this._closePeer(state);
        this.peers.delete(recordingId);
    }

    _closePeer(state) {
        state.pendingCandidates = [];
        state.pc.close();
    }

    async _flushPendingCandidates(state) {
        if (!state?.pc?.remoteDescription || !state.pendingCandidates.length) {
            return;
        }

        const pendingCandidates = state.pendingCandidates.splice(0, state.pendingCandidates.length);
        for (const candidate of pendingCandidates) {
            await state.pc.addIceCandidate(candidate);
        }
    }

    _sendOffer(state) {
        const signaling = this.getSignaling();
        if (!signaling || typeof signaling.sendRecordingOffer !== 'function') {
            return;
        }

        signaling.sendRecordingOffer({
            recordingId: state.recordingId,
            connectionId: state.connectionId,
            participantId: this.getParticipantId() || '',
            sdp: state.pc.localDescription?.sdp || ''
        });
    }

    _sendCandidate(state, candidate) {
        const signaling = this.getSignaling();
        if (!signaling || typeof signaling.sendRecordingCandidate !== 'function') {
            return;
        }

        signaling.sendRecordingCandidate({
            recordingId: state.recordingId,
            connectionId: state.connectionId,
            participantId: this.getParticipantId() || '',
            candidate: candidate.candidate,
            sdpMid: candidate.sdpMid,
            sdpMLineIndex: candidate.sdpMLineIndex
        });
    }

    _sendStatus(request, status) {
        const signaling = this.getSignaling();
        if (!signaling || typeof signaling.sendRecordingStatus !== 'function') {
            return;
        }

        signaling.sendRecordingStatus({
            recordingId: request.recordingId,
            connectionId: request.connectionId || this.getConnectionId(),
            participantId: this.getParticipantId() || '',
            status
        });
    }
}