Misc fixes for group call widgets (#2657)

* Fix GroupCallEventHandler in matryoshka mode

GroupCallEventHandler needs to see a 'Syncing' event before it starts handling any events, so emit one immediately in matryoshka mode.

* Implement joinRoom on RoomWidgetClient

Element Call has undergone some changes to how it loads rooms, meaning that this method must be implemented for the app to work in matryoshka mode.

* Allow audio and video to be muted before local call feed exists

This is desirable for the Element Web integration of Element Call, because we need to be able to mute our devices before ever joining the call or creating a call feed, if the users requests it.

* Fix a strict mode error

src/embedded.ts

@@ -131,7 +131,7 @@ export class RoomWidgetClient extends MatrixClient {
                 });
             }) ?? [],
         );
-        this.setSyncState(SyncState.Prepared);
+        this.setSyncState(SyncState.Syncing);
         logger.info("Finished backfilling events");
 
         // Watch for TURN servers, if requested
@@ -146,6 +146,11 @@ export class RoomWidgetClient extends MatrixClient {
         this.lifecycle.abort(); // Signal to other async tasks that the client has stopped
     }
 
+    public async joinRoom(roomIdOrAlias: string): Promise<Room> {
+        if (roomIdOrAlias === this.roomId) return this.room;
+        throw new Error(`Unknown room: ${roomIdOrAlias}`);
+    }
+
     public async sendStateEvent(
         roomId: string,
         eventType: string,

src/webrtc/groupCall.ts

@@ -183,6 +183,8 @@ export class GroupCall extends TypedEventEmitter<
     private transmitTimer: ReturnType<typeof setTimeout> | null = null;
     private memberStateExpirationTimers: Map<string, ReturnType<typeof setTimeout>> = new Map();
     private resendMemberStateTimer: ReturnType<typeof setInterval> | null = null;
+    private initWithAudioMuted = false;
+    private initWithVideoMuted = false;
 
     constructor(
         private client: MatrixClient,
@@ -261,23 +263,21 @@ export class GroupCall extends TypedEventEmitter<
             throw error;
         }
 
-        // start muted on ptt calls
-        if (this.isPtt) {
-            setTracksEnabled(stream.getAudioTracks(), false);
-        }
-
-        const userId = this.client.getUserId();
+        const userId = this.client.getUserId()!;
 
         const callFeed = new CallFeed({
             client: this.client,
             roomId: this.room.roomId,
             userId,
             stream,
             purpose: SDPStreamMetadataPurpose.Usermedia,
-            audioMuted: stream.getAudioTracks().length === 0 || this.isPtt,
-            videoMuted: stream.getVideoTracks().length === 0,
+            audioMuted: this.initWithAudioMuted || stream.getAudioTracks().length === 0 || this.isPtt,
+            videoMuted: this.initWithVideoMuted || stream.getVideoTracks().length === 0,
         });
 
+        setTracksEnabled(stream.getAudioTracks(), !callFeed.isAudioMuted());
+        setTracksEnabled(stream.getVideoTracks(), !callFeed.isVideoMuted());
+
         this.localCallFeed = callFeed;
         this.addUserMediaFeed(callFeed);
 
@@ -496,6 +496,9 @@ export class GroupCall extends TypedEventEmitter<
             // given to any of the actual calls, so these tracks don't actually go
             // anywhere. Let's do it anyway to avoid confusion.
             setTracksEnabled(this.localCallFeed.stream.getAudioTracks(), !muted);
+        } else {
+            logger.log(`groupCall ${this.groupCallId} setMicrophoneMuted no stream muted ${muted}`);
+            this.initWithAudioMuted = muted;
         }
 
         for (const call of this.calls) {
@@ -532,6 +535,9 @@ export class GroupCall extends TypedEventEmitter<
                 this.localCallFeed.stream.id} muted ${muted}`);
             this.localCallFeed.setAudioVideoMuted(null, muted);
             setTracksEnabled(this.localCallFeed.stream.getVideoTracks(), !muted);
+        } else {
+            logger.log(`groupCall ${this.groupCallId} setLocalVideoMuted no stream muted ${muted}`);
+            this.initWithVideoMuted = muted;
         }
 
         for (const call of this.calls) {