Make MatrixCall use CallFeed

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

src/webrtc/callFeed.ts

@@ -14,15 +14,40 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import EventEmitter from "events";
+
 export enum CallFeedType {
     Webcam = "webcam",
     Screenshare = "screenshare",
 }
 
-export class CallFeed {
+export enum CallFeedEvent {
+    NewStream = "new_stream",
+}
+
+export class CallFeed extends EventEmitter {
     constructor(
         public stream: MediaStream,
         public userId: string,
         public type: CallFeedType,
-    ) {}
+        private client: any, // Fix when client is TSified
+    ) {
+        super()
+    }
+
+    public isLocal() {
+        return this.userId === this.client.getUserId();
+    }
+
+    // TODO: This should be later replaced by a method
+    // that will also check if the remote is muted.
+    public isAudioOnly(): boolean {
+        // We assume only one video track
+        return !this.stream.getTracks().some((track) => track.kind === "video");
+    }
+
+    public setNewStream(newStream: MediaStream) {
+        this.stream = newStream;
+        this.emit(CallFeedEvent.NewStream, this.stream);
+    }
 }