When start listening to a broadcast, pause the others (#9489)

src/voice-broadcast/models/VoiceBroadcastPlayback.ts

@@ -47,7 +47,10 @@ export enum VoiceBroadcastPlaybackEvent {
 
 interface EventMap {
     [VoiceBroadcastPlaybackEvent.LengthChanged]: (length: number) => void;
-    [VoiceBroadcastPlaybackEvent.StateChanged]: (state: VoiceBroadcastPlaybackState) => void;
+    [VoiceBroadcastPlaybackEvent.StateChanged]: (
+        state: VoiceBroadcastPlaybackState,
+        playback: VoiceBroadcastPlayback
+    ) => void;
     [VoiceBroadcastPlaybackEvent.InfoStateChanged]: (state: VoiceBroadcastInfoState) => void;
 }
 
@@ -217,14 +220,20 @@ export class VoiceBroadcastPlayback
     }
 
     public pause(): void {
-        if (!this.currentlyPlaying) return;
+        // stopped voice broadcasts cannot be paused
+        if (this.getState() === VoiceBroadcastPlaybackState.Stopped) return;
 
         this.setState(VoiceBroadcastPlaybackState.Paused);
+        if (!this.currentlyPlaying) return;
         this.currentlyPlaying.pause();
     }
 
     public resume(): void {
-        if (!this.currentlyPlaying) return;
+        if (!this.currentlyPlaying) {
+            // no playback to resume, start from the beginning
+            this.start();
+            return;
+        }
 
         this.setState(VoiceBroadcastPlaybackState.Playing);
         this.currentlyPlaying.play();
@@ -260,7 +269,7 @@ export class VoiceBroadcastPlayback
         }
 
         this.state = state;
-        this.emit(VoiceBroadcastPlaybackEvent.StateChanged, state);
+        this.emit(VoiceBroadcastPlaybackEvent.StateChanged, state, this);
     }
 
     public getInfoState(): VoiceBroadcastInfoState {

src/voice-broadcast/stores/VoiceBroadcastPlaybacksStore.ts

@@ -17,7 +17,8 @@ limitations under the License.
 import { MatrixClient, MatrixEvent } from "matrix-js-sdk/src/matrix";
 import { TypedEventEmitter } from "matrix-js-sdk/src/models/typed-event-emitter";
 
-import { VoiceBroadcastPlayback } from "..";
+import { VoiceBroadcastPlayback, VoiceBroadcastPlaybackEvent, VoiceBroadcastPlaybackState } from "..";
+import { IDestroyable } from "../../utils/IDestroyable";
 
 export enum VoiceBroadcastPlaybacksStoreEvent {
     CurrentChanged = "current_changed",
@@ -28,10 +29,16 @@ interface EventMap {
 }
 
 /**
- * This store provides access to the current and specific Voice Broadcast playbacks.
+ * This store manages VoiceBroadcastPlaybacks:
+ * - access the currently playing voice broadcast
+ * - ensures that only once broadcast is playing at a time
  */
-export class VoiceBroadcastPlaybacksStore extends TypedEventEmitter<VoiceBroadcastPlaybacksStoreEvent, EventMap> {
+export class VoiceBroadcastPlaybacksStore
+    extends TypedEventEmitter<VoiceBroadcastPlaybacksStoreEvent, EventMap>
+    implements IDestroyable {
     private current: VoiceBroadcastPlayback | null;
+
+    /** Playbacks indexed by their info event id. */
     private playbacks = new Map<string, VoiceBroadcastPlayback>();
 
     public constructor() {
@@ -42,7 +49,7 @@ export class VoiceBroadcastPlaybacksStore extends TypedEventEmitter<VoiceBroadca
         if (this.current === current) return;
 
         this.current = current;
-        this.playbacks.set(current.infoEvent.getId(), current);
+        this.addPlayback(current);
         this.emit(VoiceBroadcastPlaybacksStoreEvent.CurrentChanged, current);
     }
 
@@ -54,12 +61,51 @@ export class VoiceBroadcastPlaybacksStore extends TypedEventEmitter<VoiceBroadca
         const infoEventId = infoEvent.getId();
 
         if (!this.playbacks.has(infoEventId)) {
-            this.playbacks.set(infoEventId, new VoiceBroadcastPlayback(infoEvent, client));
+            this.addPlayback(new VoiceBroadcastPlayback(infoEvent, client));
         }
 
         return this.playbacks.get(infoEventId);
     }
 
+    private addPlayback(playback: VoiceBroadcastPlayback): void {
+        const infoEventId = playback.infoEvent.getId();
+
+        if (this.playbacks.has(infoEventId)) return;
+
+        this.playbacks.set(infoEventId, playback);
+        playback.on(VoiceBroadcastPlaybackEvent.StateChanged, this.onPlaybackStateChanged);
+    }
+
+    private onPlaybackStateChanged = (
+        state: VoiceBroadcastPlaybackState,
+        playback: VoiceBroadcastPlayback,
+    ): void => {
+        if ([
+            VoiceBroadcastPlaybackState.Buffering,
+            VoiceBroadcastPlaybackState.Playing,
+        ].includes(state)) {
+            this.pauseExcept(playback);
+        }
+    };
+
+    private pauseExcept(playbackNotToPause: VoiceBroadcastPlayback): void {
+        for (const playback of this.playbacks.values()) {
+            if (playback !== playbackNotToPause) {
+                playback.pause();
+            }
+        }
+    }
+
+    public destroy(): void {
+        this.removeAllListeners();
+
+        for (const playback of this.playbacks.values()) {
+            playback.off(VoiceBroadcastPlaybackEvent.StateChanged, this.onPlaybackStateChanged);
+        }
+
+        this.playbacks = new Map();
+    }
+
     public static readonly _instance = new VoiceBroadcastPlaybacksStore();
 
     /**