Tidy some things up, refactor dialing/ringing behaviors

src/room/CallEventAudioRenderer.test.tsx

@@ -19,10 +19,7 @@ import { act } from "react";
 import { type CallMembership } from "matrix-js-sdk/lib/matrixrtc";
 
 import { mockRtcMembership } from "../utils/test";
-import {
+import { CallEventAudioRenderer } from "./CallEventAudioRenderer";
-  CallEventAudioRenderer,
-  MAX_PARTICIPANT_COUNT_FOR_SOUND,
-} from "./CallEventAudioRenderer";
 import { useAudioContext } from "../useAudioContext";
 import { prefetchSounds } from "../soundUtils";
 import { getBasicCallViewModelEnvironment } from "../utils/test-viewmodel";
@@ -33,6 +30,7 @@ import {
   local,
   localRtcMember,
 } from "../utils/test-fixtures";
+import { MAX_PARTICIPANT_COUNT_FOR_SOUND } from "../state/CallViewModel";
 
 vitest.mock("../useAudioContext");
 vitest.mock("../soundUtils");
@@ -172,7 +170,7 @@ test("should not play a sound when a hand raise is retracted", () => {
       },
     });
   });
-  expect(playSound).toHaveBeenCalledTimes(2);
+  expect(playSound).toHaveBeenCalledTimes(1);
   act(() => {
     handRaisedSubject$.next({
       ["foo"]: {
@@ -182,5 +180,5 @@ test("should not play a sound when a hand raise is retracted", () => {
       },
     });
   });
-  expect(playSound).toHaveBeenCalledTimes(2);
+  expect(playSound).toHaveBeenCalledTimes(1);
 });

src/room/CallEventAudioRenderer.tsx

@@ -6,7 +6,6 @@ Please see LICENSE in the repository root for full details.
 */
 
 import { type ReactNode, useEffect } from "react";
-import { filter, interval, throttle } from "rxjs";
 
 import { type CallViewModel } from "../state/CallViewModel";
 import joinCallSoundMp3 from "../sound/join_call.mp3";
@@ -21,11 +20,6 @@ import { useAudioContext } from "../useAudioContext";
 import { prefetchSounds } from "../soundUtils";
 import { useLatest } from "../useLatest";
 
-// Do not play any sounds if the participant count has exceeded this
-// number.
-export const MAX_PARTICIPANT_COUNT_FOR_SOUND = 8;
-export const THROTTLE_SOUND_EFFECT_MS = 500;
-
 export const callEventAudioSounds = prefetchSounds({
   join: {
     mp3: joinCallSoundMp3,
@@ -60,37 +54,18 @@ export function CallEventAudioRenderer({
   const audioEngineRef = useLatest(audioEngineCtx);
 
   useEffect(() => {
-    const joinSub = vm.participantChanges$
+    const joinSub = vm.joinSoundEffect$.subscribe(
-      .pipe(
+      () => void audioEngineRef.current?.playSound("join"),
-        filter(
+    );
-          ({ joined, ids }) =>
+    const leftSub = vm.leaveSoundEffect$.subscribe(
-            ids.length <= MAX_PARTICIPANT_COUNT_FOR_SOUND && joined.length > 0,
+      () => void audioEngineRef.current?.playSound("left"),
-        ),
+    );
-        throttle(() => interval(THROTTLE_SOUND_EFFECT_MS)),
+    const handRaisedSub = vm.newHandRaised$.subscribe(
-      )
+      () => void audioEngineRef.current?.playSound("raiseHand"),
-      .subscribe(() => {
+    );
-        void audioEngineRef.current?.playSound("join");
+    const screenshareSub = vm.newScreenShare$.subscribe(
-      });
+      () => void audioEngineRef.current?.playSound("screenshareStarted"),
-
+    );
-    const leftSub = vm.participantChanges$
-      .pipe(
-        filter(
-          ({ ids, left }) =>
-            ids.length <= MAX_PARTICIPANT_COUNT_FOR_SOUND && left.length > 0,
-        ),
-        throttle(() => interval(THROTTLE_SOUND_EFFECT_MS)),
-      )
-      .subscribe(() => {
-        void audioEngineRef.current?.playSound("left");
-      });
-
-    const handRaisedSub = vm.newHandRaised$.subscribe(() => {
-      void audioEngineRef.current?.playSound("raiseHand");
-    });
-
-    const screenshareSub = vm.newScreenShare$.subscribe(() => {
-      void audioEngineRef.current?.playSound("screenshareStarted");
-    });
 
     return (): void => {
       joinSub.unsubscribe();

src/room/InCallView.tsx

@@ -321,7 +321,7 @@ export const InCallView: FC<InCallViewProps> = ({
   const showFooter = useBehavior(vm.showFooter$);
   const earpieceMode = useBehavior(vm.earpieceMode$);
   const audioOutputSwitcher = useBehavior(vm.audioOutputSwitcher$);
-  useSubscription(vm.autoLeaveWhenOthersLeft$, onLeave);
+  useSubscription(vm.autoLeave$, onLeave);
 
   // Ideally we could detect taps by listening for click events and checking
   // that the pointerType of the event is "touch", but this isn't yet supported

src/state/CallViewModel.test.ts

@@ -311,7 +311,7 @@ function withCallViewModel(
 
   const roomEventSelectorSpy = vi
     .spyOn(ComponentsCore, "roomEventSelector")
-    .mockImplementation((room, eventType) => of());
+    .mockImplementation((_room, _eventType) => of());
 
   const livekitRoom = mockLivekitRoom(
     { localParticipant },
@@ -1071,9 +1071,9 @@ it("should rank raised hands above video feeds and below speakers and presenters
 });
 
 function nooneEverThere$<T>(
-  hot: (marbles: string, values: Record<string, T[]>) => Observable<T[]>,
+  behavior: (marbles: string, values: Record<string, T[]>) => Behavior<T[]>,
-): Observable<T[]> {
+): Behavior<T[]> {
-  return hot("a-b-c-d", {
+  return behavior("a-b-c-d", {
     a: [], // Start empty
     b: [], // Alice joins
     c: [], // Alice still there
@@ -1082,12 +1082,12 @@ function nooneEverThere$<T>(
 }
 
 function participantJoinLeave$(
-  hot: (
+  behavior: (
     marbles: string,
     values: Record<string, RemoteParticipant[]>,
-  ) => Observable<RemoteParticipant[]>,
+  ) => Behavior<RemoteParticipant[]>,
-): Observable<RemoteParticipant[]> {
+): Behavior<RemoteParticipant[]> {
-  return hot("a-b-c-d", {
+  return behavior("a-b-c-d", {
     a: [], // Start empty
     b: [aliceParticipant], // Alice joins
     c: [aliceParticipant], // Alice still there
@@ -1096,12 +1096,12 @@ function participantJoinLeave$(
 }
 
 function rtcMemberJoinLeave$(
-  hot: (
+  behavior: (
     marbles: string,
     values: Record<string, CallMembership[]>,
-  ) => Observable<CallMembership[]>,
+  ) => Behavior<CallMembership[]>,
-): Observable<CallMembership[]> {
+): Behavior<CallMembership[]> {
-  return hot("a-b-c-d", {
+  return behavior("a-b-c-d", {
     a: [localRtcMember], // Start empty
     b: [localRtcMember, aliceRtcMember], // Alice joins
     c: [localRtcMember, aliceRtcMember], // Alice still there
@@ -1109,47 +1109,15 @@ function rtcMemberJoinLeave$(
   });
 }
 
-test("allOthersLeft$ emits only when someone joined and then all others left", () => {
+test("autoLeave$ emits only when autoLeaveWhenOthersLeft option is enabled", () => {
-  withTestScheduler(({ hot, expectObservable, scope }) => {
+  withTestScheduler(({ behavior, expectObservable }) => {
-    // Test scenario 1: No one ever joins - should only emit initial false and never emit again
-    withCallViewModel(
-      { remoteParticipants$: scope.behavior(nooneEverThere$(hot), []) },
-      (vm) => {
-        expectObservable(vm.allOthersLeft$).toBe("n------", { n: false });
-      },
-    );
-  });
-});
-
-test("allOthersLeft$ emits true when someone joined and then all others left", () => {
-  withTestScheduler(({ hot, expectObservable, scope }) => {
     withCallViewModel(
       {
-        remoteParticipants$: scope.behavior(participantJoinLeave$(hot), []),
+        remoteParticipants$: participantJoinLeave$(behavior),
-        rtcMembers$: scope.behavior(rtcMemberJoinLeave$(hot), []),
+        rtcMembers$: rtcMemberJoinLeave$(behavior),
       },
       (vm) => {
-        expectObservable(vm.allOthersLeft$).toBe(
+        expectObservable(vm.autoLeave$).toBe("------(e|)", { e: undefined });
-          "n-----u", // false initially, then at frame 6: true then false emissions in same frame
-          { n: false, u: true }, // map(() => {})
-        );
-      },
-    );
-  });
-});
-
-test("autoLeaveWhenOthersLeft$ emits only when autoLeaveWhenOthersLeft option is enabled", () => {
-  withTestScheduler(({ hot, expectObservable, scope }) => {
-    withCallViewModel(
-      {
-        remoteParticipants$: scope.behavior(participantJoinLeave$(hot), []),
-        rtcMembers$: scope.behavior(rtcMemberJoinLeave$(hot), []),
-      },
-      (vm) => {
-        expectObservable(vm.autoLeaveWhenOthersLeft$).toBe(
-          "------e", // false initially, then at frame 6: true then false emissions in same frame
-          { e: undefined },
-        );
       },
       {
         autoLeaveWhenOthersLeft: true,
@@ -1159,15 +1127,15 @@ test("autoLeaveWhenOthersLeft$ emits only when autoLeaveWhenOthersLeft option is
   });
 });
 
-test("autoLeaveWhenOthersLeft$ never emits autoLeaveWhenOthersLeft option is enabled but no-one is there", () => {
+test("autoLeave$ never emits autoLeaveWhenOthersLeft option is enabled but no-one is there", () => {
-  withTestScheduler(({ hot, expectObservable, scope }) => {
+  withTestScheduler(({ behavior, expectObservable }) => {
     withCallViewModel(
       {
-        remoteParticipants$: scope.behavior(nooneEverThere$(hot), []),
+        remoteParticipants$: nooneEverThere$(behavior),
-        rtcMembers$: scope.behavior(nooneEverThere$(hot), []),
+        rtcMembers$: nooneEverThere$(behavior),
       },
       (vm) => {
-        expectObservable(vm.autoLeaveWhenOthersLeft$).toBe("-------");
+        expectObservable(vm.autoLeave$).toBe("-");
       },
       {
         autoLeaveWhenOthersLeft: true,
@@ -1177,15 +1145,15 @@ test("autoLeaveWhenOthersLeft$ never emits autoLeaveWhenOthersLeft option is ena
   });
 });
 
-test("autoLeaveWhenOthersLeft$ doesn't emit when autoLeaveWhenOthersLeft option is disabled and all others left", () => {
+test("autoLeave$ doesn't emit when autoLeaveWhenOthersLeft option is disabled and all others left", () => {
-  withTestScheduler(({ hot, expectObservable, scope }) => {
+  withTestScheduler(({ behavior, expectObservable }) => {
     withCallViewModel(
       {
-        remoteParticipants$: scope.behavior(participantJoinLeave$(hot), []),
+        remoteParticipants$: participantJoinLeave$(behavior),
-        rtcMembers$: scope.behavior(rtcMemberJoinLeave$(hot), []),
+        rtcMembers$: rtcMemberJoinLeave$(behavior),
       },
       (vm) => {
-        expectObservable(vm.autoLeaveWhenOthersLeft$).toBe("-------");
+        expectObservable(vm.autoLeave$).toBe("-");
       },
       {
         autoLeaveWhenOthersLeft: false,
@@ -1195,31 +1163,25 @@ test("autoLeaveWhenOthersLeft$ doesn't emit when autoLeaveWhenOthersLeft option
   });
 });
 
-test("autoLeaveWhenOthersLeft$ doesn't emits when autoLeaveWhenOthersLeft option is enabled and all others left", () => {
+test("autoLeave$ emits when autoLeaveWhenOthersLeft option is enabled and all others left", () => {
-  withTestScheduler(({ hot, expectObservable, scope }) => {
+  withTestScheduler(({ behavior, expectObservable }) => {
     withCallViewModel(
       {
-        remoteParticipants$: scope.behavior(
+        remoteParticipants$: behavior("a-b-c-d", {
-          hot("a-b-c-d", {
+          a: [], // Alone
-            a: [], // Alone
+          b: [aliceParticipant], // Alice joins
-            b: [aliceParticipant], // Alice joins
+          c: [aliceParticipant],
-            c: [aliceParticipant],
+          d: [], // Local joins with a second device
-            d: [], // Local joins with a second device
+        }),
-          }),
+        rtcMembers$: behavior("a-b-c-d", {
-          [], //Alice leaves
+          a: [localRtcMember], // Start empty
-        ),
+          b: [localRtcMember, aliceRtcMember], // Alice joins
-        rtcMembers$: scope.behavior(
+          c: [localRtcMember, aliceRtcMember, localRtcMemberDevice2], // Alice still there
-          hot("a-b-c-d", {
+          d: [localRtcMember, localRtcMemberDevice2], // The second Alice leaves
-            a: [localRtcMember], // Start empty
+        }),
-            b: [localRtcMember, aliceRtcMember], // Alice joins
-            c: [localRtcMember, aliceRtcMember, localRtcMemberDevice2], // Alice still there
-            d: [localRtcMember, localRtcMemberDevice2], // The second Alice leaves
-          }),
-          [],
-        ),
       },
       (vm) => {
-        expectObservable(vm.autoLeaveWhenOthersLeft$).toBe("------e", {
+        expectObservable(vm.autoLeave$).toBe("------(e|)", {
           e: undefined,
         });
       },

src/state/CallViewModel.ts

@@ -27,6 +27,7 @@ import {
 import {
   BehaviorSubject,
   EMPTY,
+  NEVER,
   type Observable,
   Subject,
   combineLatest,
@@ -35,10 +36,12 @@ import {
   filter,
   forkJoin,
   fromEvent,
+  ignoreElements,
   map,
   merge,
   mergeMap,
   of,
+  pairwise,
   race,
   scan,
   skip,
@@ -47,13 +50,14 @@ import {
   switchMap,
   switchScan,
   take,
+  takeUntil,
+  throttleTime,
   timer,
   withLatestFrom,
 } from "rxjs";
 import { logger } from "matrix-js-sdk/lib/logger";
 import {
   type CallMembership,
-  type ICallNotifyContent,
   type IRTCNotificationContent,
   type MatrixRTCSession,
   MatrixRTCSessionEvent,
@@ -107,7 +111,7 @@ import { observeSpeaker$ } from "./observeSpeaker";
 import { shallowEquals } from "../utils/array";
 import { calculateDisplayName, shouldDisambiguate } from "../utils/displayname";
 import { type MediaDevices } from "./MediaDevices";
-import { type Behavior } from "./Behavior";
+import { constant, type Behavior } from "./Behavior";
 
 export interface CallViewModelOptions {
   encryptionSystem: EncryptionSystem;
@@ -123,6 +127,11 @@ export interface CallViewModelOptions {
 // list again
 const POST_FOCUS_PARTICIPANT_UPDATE_DELAY_MS = 3000;
 
+// Do not play any sounds if the participant count has exceeded this
+// number.
+export const MAX_PARTICIPANT_COUNT_FOR_SOUND = 8;
+export const THROTTLE_SOUND_EFFECT_MS = 500;
+
 // This is the number of participants that we think constitutes a "small" call
 // on mobile. No spotlight tile should be shown below this threshold.
 const smallMobileCallThreshold = 3;
@@ -563,6 +572,17 @@ export class CallViewModel extends ViewModel {
     )
     .pipe(pauseWhen(this.pretendToBeDisconnected$));
 
+  private readonly memberships$ = this.scope.behavior(
+    fromEvent(
+      this.matrixRTCSession,
+      MatrixRTCSessionEvent.MembershipsChanged,
+    ).pipe(
+      startWith(null),
+      pauseWhen(this.pretendToBeDisconnected$),
+      map(() => this.matrixRTCSession.memberships),
+    ),
+  );
+
   /**
    * Displaynames for each member of the call. This will disambiguate
    * any displaynames that clashes with another member. Only members
@@ -572,18 +592,17 @@ export class CallViewModel extends ViewModel {
   // than on Chrome/Firefox). This means it is important that we multicast the result so that we
   // don't do this work more times than we need to. This is achieved by converting to a behavior:
   public readonly memberDisplaynames$ = this.scope.behavior(
-    merge(
+    // React to call memberships and also display name updates
-      // Handle call membership changes.
+    // (calculateDisplayName implicitly depends on the room member data)
-      fromEvent(
+    combineLatest(
-        this.matrixRTCSession,
+      [
-        MatrixRTCSessionEvent.MembershipsChanged,
+        this.memberships$,
-      ),
+        fromEvent(this.matrixRoom, RoomStateEvent.Members).pipe(
-      // Handle room membership changes (and displayname updates)
+          startWith(null),
-      fromEvent(this.matrixRoom, RoomStateEvent.Members),
+          pauseWhen(this.pretendToBeDisconnected$),
-    ).pipe(
+        ),
-      startWith(null),
+      ],
-      map(() => {
+      (memberships, _members) => {
-        const memberships = this.matrixRTCSession.memberships;
         const displaynameMap = new Map<string, string>();
         const room = this.matrixRoom;
 
@@ -605,8 +624,7 @@ export class CallViewModel extends ViewModel {
           );
         }
         return displaynameMap;
-      }),
+      },
-      pauseWhen(this.pretendToBeDisconnected$),
     ),
   );
 
@@ -636,13 +654,7 @@ export class CallViewModel extends ViewModel {
       this.remoteParticipants$,
       observeParticipantMedia(this.livekitRoom.localParticipant),
       duplicateTiles.value$,
-      // Also react to changes in the MatrixRTC session list.
+      this.memberships$,
-      // The session list will also be update if a room membership changes.
-      // No additional RoomState event listener needs to be set up.
-      fromEvent(
-        this.matrixRTCSession,
-        MatrixRTCSessionEvent.MembershipsChanged,
-      ).pipe(startWith(null), pauseWhen(this.pretendToBeDisconnected$)),
       showNonMemberTiles.value$,
     ]).pipe(
       scan(
@@ -652,7 +664,7 @@ export class CallViewModel extends ViewModel {
             remoteParticipants,
             { participant: localParticipant },
             duplicateTiles,
-            _membershipsChanged,
+            memberships,
             showNonMemberTiles,
           ],
         ) => {
@@ -660,7 +672,7 @@ export class CallViewModel extends ViewModel {
             function* (this: CallViewModel): Iterable<[string, MediaItem]> {
               const room = this.matrixRoom;
               // m.rtc.members are the basis for calculating what is visible in the call
-              for (const rtcMember of this.matrixRTCSession.memberships) {
+              for (const rtcMember of memberships) {
                 const { member, id: livekitParticipantId } =
                   getRoomMemberFromRtcMember(rtcMember, room);
                 const matrixIdentifier = `${rtcMember.sender}:${rtcMember.deviceId}`;
@@ -826,175 +838,117 @@ export class CallViewModel extends ViewModel {
     ),
   );
 
-  /**
+  public readonly joinSoundEffect$ = this.userMedia$.pipe(
-   * This observable tracks the currently connected participants.
+    pairwise(),
-   *
+    filter(
-   *  - Each participant has one livekit connection
+      ([prev, current]) =>
-   *  - Each participant has a corresponding MatrixRTC membership state event
+        current.length <= MAX_PARTICIPANT_COUNT_FOR_SOUND &&
-   *  - There can be multiple participants for one matrix user.
+        current.length > prev.length,
-   */
-  public readonly participantChanges$ = this.scope.behavior(
-    this.userMedia$.pipe(
-      map((mediaItems) => mediaItems.map((m) => m.id)),
-      scan<string[], { ids: string[]; joined: string[]; left: string[] }>(
-        (prev, ids) => {
-          const left = prev.ids.filter((id) => !ids.includes(id));
-          const joined = ids.filter((id) => !prev.ids.includes(id));
-          return { ids, joined, left };
-        },
-        { ids: [], joined: [], left: [] },
-      ),
     ),
+    map(() => {}),
+    throttleTime(THROTTLE_SOUND_EFFECT_MS),
+  );
+
+  public readonly leaveSoundEffect$ = this.userMedia$.pipe(
+    pairwise(),
+    filter(
+      ([prev, current]) =>
+        current.length <= MAX_PARTICIPANT_COUNT_FOR_SOUND &&
+        current.length < prev.length,
+    ),
+    map(() => {}),
+    throttleTime(THROTTLE_SOUND_EFFECT_MS),
   );
 
   /**
    * The number of participants currently in the call.
    *
-   *  - Each participant has one livekit connection
    *  - Each participant has a corresponding MatrixRTC membership state event
-   *  - There can be multiple participants for one matrix user.
+   *  - There can be multiple participants for one Matrix user if they join from
+   *    multiple devices.
    */
   public readonly participantCount$ = this.scope.behavior(
-    this.participantChanges$.pipe(map(({ ids }) => ids.length)),
+    this.memberships$.pipe(map((ms) => ms.length)),
   );
 
-  /**
+  private readonly allOthersLeft$ = this.memberships$.pipe(
-   * This observable tracks the matrix users that are currently in the call.
+    pairwise(),
-   * There can be just one matrix user with multiple participants (see also participantChanges$)
+    filter(
-   */
+      ([prev, current]) =>
-  public readonly matrixUserChanges$ = this.scope.behavior(
+        current.every((m) => m.sender === this.userId) &&
-    this.userMedia$.pipe(
+        prev.some((m) => m.sender !== this.userId),
-      map(
-        (mediaItems) =>
-          new Set(
-            mediaItems
-              .map((m) => m.vm.member?.userId)
-              .filter((id) => id !== undefined),
-          ),
-      ),
-      scan<
-        Set<string>,
-        {
-          userIds: Set<string>;
-          joinedUserIds: Set<string>;
-          leftUserIds: Set<string>;
-        }
-      >(
-        (prevState, userIds) => {
-          const left = new Set(
-            [...prevState.userIds].filter((id) => !userIds.has(id)),
-          );
-          const joined = new Set(
-            [...userIds].filter((id) => !prevState.userIds.has(id)),
-          );
-          return { userIds: userIds, joinedUserIds: joined, leftUserIds: left };
-        },
-        {
-          userIds: new Set(),
-          joinedUserIds: new Set(),
-          leftUserIds: new Set(),
-        },
-      ),
     ),
-  );
-
-  public readonly allOthersLeft$ = this.matrixUserChanges$.pipe(
-    map(({ userIds, leftUserIds }) => {
-      if (!this.userId) {
-        logger.warn("Could not access user ID to compute allOthersLeft");
-        return false;
-      }
-      return (
-        userIds.size === 1 && userIds.has(this.userId) && leftUserIds.size > 0
-      );
-    }),
-    startWith(false),
-    distinctUntilChanged(),
-  );
-
-  public readonly autoLeaveWhenOthersLeft$ = this.allOthersLeft$.pipe(
-    distinctUntilChanged(),
-    filter((leave) => (leave && this.options.autoLeaveWhenOthersLeft) ?? false),
     map(() => {}),
+    take(1),
   );
 
-  /**
+  public readonly autoLeave$ = this.options.autoLeaveWhenOthersLeft
-   * "unknown": We don't know if the RTC session decides to send a notify event yet.
+    ? this.allOthersLeft$
-   *   It will only be known once we sent our own membership and know we were the first one to join.
+    : NEVER;
-   * "ringing": The notification event was sent.
-   * "ringEnded": The notification events lifetime has timed out -> ringing stopped on all receiving clients.
-   */
-  private readonly notificationEventIsRingingOthers$: Observable<
-    "unknown" | "ringing" | "ringEnded" | null
-  > = fromEvent<[IRTCNotificationContent, ICallNotifyContent]>(
-    this.matrixRTCSession,
-    MatrixRTCSessionEvent.DidSendCallNotification,
-  ).pipe(
-    switchMap(([notificationEvent]) => {
-      // event.lifetime is expected to be in ms
-      const lifetime = notificationEvent?.lifetime ?? 0;
-      if (lifetime > 0) {
-        // Emit true immediately, then false after lifetime ms
-        return concat(
-          of<"ringing" | null>("ringing"),
-          timer(lifetime).pipe(map((): "ringEnded" | null => "ringEnded")),
-        );
-      }
-      // If no lifetime, just emit true once
-      return of(null);
-    }),
-    startWith("unknown" as "unknown" | null),
-  );
 
   /**
-   * If some other matrix user has joined the call. It can start with true if there are already multiple matrix users.
+   * Emits whenever the RTC session tells us that it intends to ring for a given
+   * duration.
    */
-  private readonly someoneElseJoined$ = this.matrixUserChanges$.pipe(
+  private readonly beginRingingForMs$ = (
-    scan(
+    fromEvent(
-      (someoneJoined, { joinedUserIds }) =>
+      this.matrixRTCSession,
-        someoneJoined || [...joinedUserIds].some((id) => id !== this.userId),
+      MatrixRTCSessionEvent.DidSendCallNotification,
-      false,
+    ) as Observable<[IRTCNotificationContent]>
-    ),
+  )
-    startWith(this.matrixUserChanges$.value.userIds.size > 1),
+    // event.lifetime is expected to be in ms
+    .pipe(map(([notificationEvent]) => notificationEvent?.lifetime ?? 0));
+
+  /**
+   * Whether some Matrix user other than ourself is joined to the call.
+   */
+  private readonly someoneElseJoined$ = this.memberships$.pipe(
+    map((ms) => ms.some((m) => m.sender !== this.userId)),
   );
 
   /**
    * The current call pickup state of the call.
-   *  - "ringing": The call is ringing on other devices in this room (This client should give audiovisual feedback that this is happening).
    *  - "unknown": The client has not yet sent the notification event. We don't know if it will because it first needs to send its own membership.
    *     Then we can conclude if we were the first one to join or not.
+   *  - "ringing": The call is ringing on other devices in this room (This client should give audiovisual feedback that this is happening).
    *  - "timeout": No-one picked up in the defined time this call should be ringing on others devices.
    *     The call failed. If desired this can be used as a trigger to exit the call.
-   *  - "success": Someone else joined. The call is in a normal state. Stop audiovisual feedback.
+   *  - "success": Someone else joined. The call is in a normal state. No audiovisual feedback.
    *  - null: EC is configured to never show any waiting for answer state.
    */
-  public readonly callPickupState$: Behavior<
+  public readonly callPickupState$ = this.options.shouldWaitForCallPickup
-    "unknown" | "ringing" | "timeout" | "success" | null
+    ? this.scope.behavior<"unknown" | "ringing" | "timeout" | "success">(
-  > = this.scope.behavior(
+        concat(
-    combineLatest([
+          concat(
-      this.notificationEventIsRingingOthers$,
+            // We don't know if the RTC session decides to send a notify event
-      this.someoneElseJoined$,
+            // yet. It will only be known once we sent our own membership and
-    ]).pipe(
+            // know we were the first one to join.
-      map(([isRingingOthers, someoneJoined]) => {
+            of("unknown" as const),
-        // Never enter waiting for answer state if the app is not configured with waitingForAnswer.
+            // Once we get the signal to begin ringing:
-        if (!this.options.shouldWaitForCallPickup) return null;
+            this.beginRingingForMs$.pipe(
-        // As soon as someone joins, we can consider the call "wait for answer" successful
+              take(1),
-        if (someoneJoined) return "success";
+              switchMap((lifetime) =>
-
+                lifetime === 0
-        switch (isRingingOthers) {
+                  ? // If no lifetime, skip the ring state
-          case "unknown":
+                    EMPTY
-            return "unknown";
+                  : // Ring until lifetime ms have passed
-          case "ringing":
+                    timer(lifetime).pipe(
-            return "ringing";
+                      ignoreElements(),
-          case "ringEnded":
+                      startWith("ringing" as const),
-            return "timeout";
+                    ),
-          default:
+              ),
-            return "timeout";
+            ),
-        }
+            // The notification lifetime has timed out, meaning ringing has
-      }),
+            // likely stopped on all receiving clients.
-      distinctUntilChanged(),
+            of("timeout" as const),
-    ),
+            NEVER,
-  );
+          ).pipe(
+            takeUntil(this.someoneElseJoined$.pipe(filter((joined) => joined))),
+          ),
+          of("success" as const),
+        ),
+      )
+    : constant(null);
 
   /**
    * List of MediaItems that we want to display, that are of type ScreenShare