MatrixRTC MembershipManger: remove redundant sendDelayedEventAction and expose status (#4747)

* Remove redundant sendDelayedEventAction
We do already have the state `hasMemberEvent` that allows to distinguish the two cases. No need to create two dedicated actions.

* fix missing return

* Make membership manager an event emitter to inform about status updates.
 - deprecate isJoined (replaced by isActivated)
 - move Interface types to types.ts

* add tests for status updates.

* lint

* test "reschedules delayed leave event" in case the delayed event gets canceled

* review

* fix types

* prettier

* fix legacy membership manager

spec/unit/matrixrtc/MembershipManager.spec.ts

@@ -20,7 +20,13 @@ limitations under the License.
 import { type MockedFunction, type Mock } from "jest-mock";
 
 import { EventType, HTTPError, MatrixError, UnsupportedDelayedEventsEndpointError, type Room } from "../../../src";
-import { type Focus, type LivekitFocusActive, type SessionMembershipData } from "../../../src/matrixrtc";
+import {
+    MembershipManagerEvent,
+    Status,
+    type Focus,
+    type LivekitFocusActive,
+    type SessionMembershipData,
+} from "../../../src/matrixrtc";
 import { LegacyMembershipManager } from "../../../src/matrixrtc/LegacyMembershipManager";
 import { makeMockClient, makeMockRoom, membershipTemplate, mockCallMembership, type MockClient } from "./mocks";
 import { MembershipManager } from "../../../src/matrixrtc/NewMembershipManager";
@@ -34,6 +40,14 @@ function waitForMockCall(method: MockedFunction<any>, returnVal?: Promise<any>)
         });
     });
 }
+function waitForMockCallOnce(method: MockedFunction<any>, returnVal?: Promise<any>) {
+    return new Promise<void>((resolve) => {
+        method.mockImplementationOnce(() => {
+            resolve();
+            return returnVal ?? Promise.resolve();
+        });
+    });
+}
 
 function createAsyncHandle(method: MockedFunction<any>) {
     const { reject, resolve, promise } = defer();
@@ -78,16 +92,16 @@ describe.each([
         // There is no need to clean up mocks since we will recreate the client.
     });
 
-    describe("isJoined()", () => {
+    describe("isActivated()", () => {
         it("defaults to false", () => {
             const manager = new TestMembershipManager({}, room, client, () => undefined);
-            expect(manager.isJoined()).toEqual(false);
+            expect(manager.isActivated()).toEqual(false);
         });
 
         it("returns true after join()", () => {
             const manager = new TestMembershipManager({}, room, client, () => undefined);
             manager.join([]);
-            expect(manager.isJoined()).toEqual(true);
+            expect(manager.isActivated()).toEqual(true);
         });
     });
 
@@ -125,6 +139,23 @@ describe.each([
                     {},
                     "_@alice:example.org_AAAAAAA",
                 );
+                expect(client._unstable_sendDelayedStateEvent).toHaveBeenCalledTimes(1);
+            });
+
+            it("reschedules delayed leave event if sending state cancels it", async () => {
+                const memberManager = new TestMembershipManager(undefined, room, client, () => undefined);
+                const waitForSendState = waitForMockCall(client.sendStateEvent);
+                const waitForUpdateDelaye = waitForMockCallOnce(
+                    client._unstable_updateDelayedEvent,
+                    Promise.reject(new MatrixError({ errcode: "M_NOT_FOUND" })),
+                );
+                memberManager.join([focus], focusActive);
+                await waitForSendState;
+                await waitForUpdateDelaye;
+                await jest.advanceTimersByTimeAsync(1);
+                // Once for the initial event and once because of the errcode: "M_NOT_FOUND"
+                // Different to "sends a membership event and schedules delayed leave when joining a call" where its only called once (1)
+                expect(client._unstable_sendDelayedStateEvent).toHaveBeenCalledTimes(2);
             });
 
             describe("does not prefix the state key with _ for rooms that support user-owned state events", () => {
@@ -505,7 +536,39 @@ describe.each([
             await testExpires(10_000, 1_000);
         });
     });
+    describe("status updates", () => {
+        it("starts 'Disconnected' !FailsForLegacy", () => {
+            const manager = new TestMembershipManager({}, room, client, () => undefined);
+            expect(manager.status).toBe(Status.Disconnected);
+        });
+        it("emits 'Connection' and 'Connected' after join !FailsForLegacy", async () => {
+            const handleDelayedEvent = createAsyncHandle(client._unstable_sendDelayedStateEvent);
+            const handleStateEvent = createAsyncHandle(client.sendStateEvent);
 
+            const manager = new TestMembershipManager({}, room, client, () => undefined);
+            expect(manager.status).toBe(Status.Disconnected);
+            const connectEmit = jest.fn();
+            manager.on(MembershipManagerEvent.StatusChanged, connectEmit);
+            manager.join([focus], focusActive);
+            expect(manager.status).toBe(Status.Connecting);
+            handleDelayedEvent.resolve();
+            await jest.advanceTimersByTimeAsync(1);
+            expect(connectEmit).toHaveBeenCalledWith(Status.Disconnected, Status.Connecting);
+            handleStateEvent.resolve();
+            await jest.advanceTimersByTimeAsync(1);
+            expect(connectEmit).toHaveBeenCalledWith(Status.Connecting, Status.Connected);
+        });
+        it("emits 'Disconnecting' and 'Disconnected' after leave !FailsForLegacy", async () => {
+            const manager = new TestMembershipManager({}, room, client, () => undefined);
+            const connectEmit = jest.fn();
+            manager.on(MembershipManagerEvent.StatusChanged, connectEmit);
+            manager.join([focus], focusActive);
+            await jest.advanceTimersByTimeAsync(1);
+            await manager.leave();
+            expect(connectEmit).toHaveBeenCalledWith(Status.Connected, Status.Disconnecting);
+            expect(connectEmit).toHaveBeenCalledWith(Status.Disconnecting, Status.Disconnected);
+        });
+    });
     describe("server error handling", () => {
         // Types of server error: 429 rate limit with no retry-after header, 429 with retry-after, 50x server error (maybe retry every second), connection/socket timeout
         describe("retries sending delayed leave event", () => {

src/matrixrtc/LegacyMembershipManager.ts

@@ -27,7 +27,7 @@ import { type Focus } from "./focus.ts";
 import { isLivekitFocusActive } from "./LivekitFocus.ts";
 import { type MembershipConfig } from "./MatrixRTCSession.ts";
 import { type EmptyObject } from "../@types/common.ts";
-import { type IMembershipManager } from "./NewMembershipManager.ts";
+import { type IMembershipManager, type MembershipManagerEvent, Status } from "./types.ts";
 
 /**
  * This internal class is used by the MatrixRTCSession to manage the local user's own membership of the session.
@@ -103,9 +103,35 @@ export class LegacyMembershipManager implements IMembershipManager {
         private getOldestMembership: () => CallMembership | undefined,
     ) {}
 
+    public off(
+        event: MembershipManagerEvent.StatusChanged,
+        listener: (oldStatus: Status, newStatus: Status) => void,
+    ): this {
+        logger.error("off is not implemented on LegacyMembershipManager");
+        return this;
+    }
+
+    public on(
+        event: MembershipManagerEvent.StatusChanged,
+        listener: (oldStatus: Status, newStatus: Status) => void,
+    ): this {
+        logger.error("on is not implemented on LegacyMembershipManager");
+        return this;
+    }
+
     public isJoined(): boolean {
         return this.relativeExpiry !== undefined;
     }
+    public isActivated(): boolean {
+        return this.isJoined();
+    }
+    /**
+     * Unimplemented
+     * @returns Status.Unknown
+     */
+    public get status(): Status {
+        return Status.Unknown;
+    }
 
     public join(fociPreferred: Focus[], fociActive?: Focus): void {
         this.ownFocusActive = fociActive;

src/matrixrtc/MatrixRTCSession.ts

@@ -25,10 +25,11 @@ import { RoomStateEvent } from "../models/room-state.ts";
 import { type Focus } from "./focus.ts";
 import { KnownMembership } from "../@types/membership.ts";
 import { type MatrixEvent } from "../models/event.ts";
-import { MembershipManager, type IMembershipManager } from "./NewMembershipManager.ts";
+import { MembershipManager } from "./NewMembershipManager.ts";
 import { EncryptionManager, type IEncryptionManager, type Statistics } from "./EncryptionManager.ts";
 import { LegacyMembershipManager } from "./LegacyMembershipManager.ts";
 import { logDurationSync } from "../utils.ts";
+import type { IMembershipManager } from "./types.ts";
 
 const logger = rootLogger.getChild("MatrixRTCSession");
 

src/matrixrtc/NewMembershipManager.ts

@@ -24,110 +24,80 @@ import { type Room } from "../models/room.ts";
 import { defer, type IDeferred } from "../utils.ts";
 import { type CallMembership, DEFAULT_EXPIRE_DURATION, type SessionMembershipData } from "./CallMembership.ts";
 import { type Focus } from "./focus.ts";
+import {
+    type IMembershipManager,
+    type MembershipManagerEventHandlerMap,
+    MembershipManagerEvent,
+    Status,
+} from "./types.ts";
 import { isLivekitFocusActive } from "./LivekitFocus.ts";
 import { type MembershipConfig } from "./MatrixRTCSession.ts";
 import { ActionScheduler, type ActionUpdate } from "./NewMembershipManagerActionScheduler.ts";
+import { TypedEventEmitter } from "../models/typed-event-emitter.ts";
 
 const logger = rootLogger.getChild("MatrixRTCSession");
 
-/**
- * This interface defines what a MembershipManager uses and exposes.
- * This interface is what we use to write tests and allows changing the actual implementation
- * without breaking tests because of some internal method renaming.
- *
- * @internal
- */
-export interface IMembershipManager {
-    /**
-     * If we are trying to join, or have successfully joined the session.
-     * It does not reflect if the room state is already configured to represent us being joined.
-     * It only means that the Manager should be trying to connect or to disconnect running.
-     * The Manager is still running right after isJoined becomes false to send the disconnect events.
-     * (A more accurate name would be `isActivated`)
-     * @returns true if we intend to be participating in the MatrixRTC session
-     */
-    isJoined(): boolean;
-    /**
-     * Start sending all necessary events to make this user participate in the RTC session.
-     * @param fociPreferred the list of preferred foci to use in the joined RTC membership event.
-     * @param fociActive the active focus to use in the joined RTC membership event.
-     * @throws can throw if it exceeds a configured maximum retry.
-     */
-    join(fociPreferred: Focus[], fociActive?: Focus, onError?: (error: unknown) => void): void;
-    /**
-     * Send all necessary events to make this user leave the RTC session.
-     * @param timeout the maximum duration in ms until the promise is forced to resolve.
-     * @returns It resolves with true in case the leave was sent successfully.
-     * It resolves with false in case we hit the timeout before sending successfully.
-     */
-    leave(timeout?: number): Promise<boolean>;
-    /**
-     * Call this if the MatrixRTC session members have changed.
-     */
-    onRTCSessionMemberUpdate(memberships: CallMembership[]): Promise<void>;
-    /**
-     * The used active focus in the currently joined session.
-     * @returns the used active focus in the currently joined session or undefined if not joined.
-     */
-    getActiveFocus(): Focus | undefined;
-}
-
 /* MembershipActionTypes:
-                           ▼
-                 ┌─────────────────────┐
-                 │SendFirstDelayedEvent│
-                 └─────────────────────┘
-                           │
-                           ▼
-                    ┌─────────────┐
-       ┌────────────│SendJoinEvent│────────────┐
-       │            └─────────────┘            │
-       │  ┌─────┐                  ┌──────┐    │    ┌──────┐
+                           
+On Join:  ───────────────┐   ┌───────────────(1)───────────┐
+                         ▼   ▼                             │
+                   ┌────────────────┐                      │
+                   │SendDelayedEvent│ ──────(2)───┐        │
+                   └────────────────┘             │        │ 
+                           │(3)                   │        │
+                           ▼                      │        │
+                    ┌─────────────┐               │        │
+       ┌──────(4)───│SendJoinEvent│────(4)─────┐  │        │
+       │            └─────────────┘            │  │        │
+       │  ┌─────┐                  ┌──────┐    │  │        │
        ▼  ▼     │                  │      ▼    ▼  ▼        │
 ┌────────────┐  │                  │ ┌───────────────────┐ │
-│UpdateExpiry│  │                  │ │RestartDelayedEvent│ │
+│UpdateExpiry│ (s)                (s)|RestartDelayedEvent│ │
 └────────────┘  │                  │ └───────────────────┘ │
           │     │                  │      │        │       │       
-          └─────┘                  └──────┘    │           │
-                                               │           │
-                 ┌────────────────────┐        │           │
-                 │SendMainDelayedEvent│◄───────┘           │
-                 └───────────────────┬┘                    │
-                                     │                     │
-                                     └─────────────────────┘
-                     STOP ALL ABOVE
+          └─────┘                  └──────┘        └───────┘ 
+     
+On Leave: ─────────  STOP ALL ABOVE
                            ▼
-            ┌───────────────────────────────┐
+            ┌────────────────────────────────┐
             │ SendScheduledDelayedLeaveEvent │
-            └───────────────────────────────┘
-                           │
+            └────────────────────────────────┘
+                           │(5)
                            ▼
                     ┌──────────────┐
                     │SendLeaveEvent│
                     └──────────────┘
-
+(1) [Not found error] results in resending the delayed event
+(2) [hasMemberEvent = true] Sending the delayed event if we
+    already have a call member event results jumping to the
+    RestartDelayedEvent loop directly
+(3) [hasMemberEvent = false] if there is not call member event
+    sending it is the next step
+(4) Both (UpdateExpiry and RestartDelayedEvent) actions are
+    scheduled when successfully sending the state event
+(5) Only if delayed event sending failed (fallback)
+(s) Successful restart/resend
 */
+
 /**
  * The different types of actions the MembershipManager can take.
  * @internal
  */
 export enum MembershipActionType {
-    SendFirstDelayedEvent = "SendFirstDelayedEvent",
+    SendDelayedEvent = "SendDelayedEvent",
     //  -> MembershipActionType.SendJoinEvent if successful
-    //  -> DelayedLeaveActionType.SendFirstDelayedEvent on error, retry sending the first delayed event.
+    //  -> DelayedLeaveActionType.SendDelayedEvent on error, retry sending the first delayed event.
+    //  -> DelayedLeaveActionType.RestartDelayedEvent on success start updating the delayed event
     SendJoinEvent = "SendJoinEvent",
     //  -> MembershipActionType.SendJoinEvent if we run into a rate limit and need to retry
     //  -> MembershipActionType.Update if we successfully send the join event then schedule the expire event update
     //  -> DelayedLeaveActionType.RestartDelayedEvent to recheck the delayed event
     RestartDelayedEvent = "RestartDelayedEvent",
     //  -> DelayedLeaveActionType.SendMainDelayedEvent on missing delay id but there is a rtc state event
-    //  -> DelayedLeaveActionType.SendFirstDelayedEvent on missing delay id and there is no state event
+    //  -> DelayedLeaveActionType.SendDelayedEvent on missing delay id and there is no state event
     //  -> DelayedLeaveActionType.RestartDelayedEvent on success we schedule the next restart
     UpdateExpiry = "UpdateExpiry",
     //  -> MembershipActionType.Update if the timeout has passed so the next update is required.
-    SendMainDelayedEvent = "SendMainDelayedEvent",
-    //  -> DelayedLeaveActionType.RestartDelayedEvent on success start updating the delayed event
-    //  -> DelayedLeaveActionType.SendMainDelayedEvent on error try again
     SendScheduledDelayedLeaveEvent = "SendScheduledDelayedLeaveEvent",
     //  -> MembershipActionType.SendLeaveEvent on failiour (not found) we need to send the leave manually and cannot use the scheduled delayed event
     //  -> DelayedLeaveActionType.SendScheduledDelayedLeaveEvent on error we try again.
@@ -138,7 +108,7 @@ export enum MembershipActionType {
 /**
  * @internal
  */
-export interface ActionSchedulerState {
+export interface MembershipManagerState {
     /** The delayId we got when successfully sending the delayed leave event.
      * Gets set to undefined if the server claims it cannot find the delayed event anymore. */
     delayId?: string;
@@ -158,17 +128,6 @@ export interface ActionSchedulerState {
     networkErrorRetries: Map<MembershipActionType, number>;
 }
 
-enum Status {
-    Disconnected = "Disconnected",
-    Connecting = "Connecting",
-    ConnectingFailed = "ConnectingFailed",
-    Connected = "Connected",
-    Reconnecting = "Reconnecting",
-    Disconnecting = "Disconnecting",
-    Stuck = "Stuck",
-    Unknown = "Unknown",
-}
-
 /**
  * This class is responsible for sending all events relating to the own membership of a matrixRTC call.
  * It has the following tasks:
@@ -182,11 +141,18 @@ enum Status {
  *   - Stop the timer for the delay refresh
  *   - Stop the timer for updating the state event
  */
-export class MembershipManager implements IMembershipManager {
+export class MembershipManager
+    extends TypedEventEmitter<MembershipManagerEvent, MembershipManagerEventHandlerMap>
+    implements IMembershipManager
+{
     private activated = false;
-    public isJoined(): boolean {
+    public isActivated(): boolean {
         return this.activated;
     }
+    // DEPRECATED use isActivated
+    public isJoined(): boolean {
+        return this.isActivated();
+    }
 
     /**
      * Puts the MembershipManager in a state where it tries to be joined.
@@ -205,23 +171,27 @@ export class MembershipManager implements IMembershipManager {
         this.focusActive = focusActive;
         this.leavePromiseDefer = undefined;
         this.activated = true;
-
+        this.oldStatus = this.status;
         this.state = MembershipManager.defaultState;
 
         this.scheduler
             .startWithJoin()
-            .then(() => {
-                if (!this.scheduler.running) {
-                    this.leavePromiseDefer?.resolve(true);
-                    this.leavePromiseDefer = undefined;
-                }
-            })
             .catch((e) => {
                 logger.error("MembershipManager stopped because: ", e);
                 onError?.(e);
             })
+            .finally(() => {
                 // Should already be set to false when calling `leave` in non error cases.
-            .finally(() => (this.activated = false));
+                this.activated = false;
+                // Here the scheduler is not running anymore so we the `membershipLoopHandler` is not called to emit.
+                if (this.oldStatus && this.oldStatus !== this.status) {
+                    this.emit(MembershipManagerEvent.StatusChanged, this.oldStatus, this.status);
+                }
+                if (!this.scheduler.running) {
+                    this.leavePromiseDefer?.resolve(true);
+                    this.leavePromiseDefer = undefined;
+                }
+            });
     }
 
     /**
@@ -256,7 +226,7 @@ export class MembershipManager implements IMembershipManager {
             // If one of these actions are scheduled or are getting inserted in the next iteration, we should already
             // take care of our missing membership.
             const sendingMembershipActions = [
-                MembershipActionType.SendFirstDelayedEvent,
+                MembershipActionType.SendDelayedEvent,
                 MembershipActionType.SendJoinEvent,
             ];
             logger.warn("Missing own membership: force re-join");
@@ -313,6 +283,7 @@ export class MembershipManager implements IMembershipManager {
         >,
         private getOldestMembership: () => CallMembership | undefined,
     ) {
+        super();
         const [userId, deviceId] = [this.client.getUserId(), this.client.getDeviceId()];
         if (userId === null) throw Error("Missing userId in client");
         if (deviceId === null) throw Error("Missing deviceId in client");
@@ -322,8 +293,8 @@ export class MembershipManager implements IMembershipManager {
     }
 
     // MembershipManager mutable state.
-    private state: ActionSchedulerState;
-    private static get defaultState(): ActionSchedulerState {
+    private state: MembershipManagerState;
+    private static get defaultState(): MembershipManagerState {
         return {
             hasMemberStateEvent: false,
             delayId: undefined,
@@ -382,7 +353,11 @@ export class MembershipManager implements IMembershipManager {
         if (this.oldStatus) {
             // we put this at the beginning of the actions scheduler loop handle callback since it is a loop this
             // is equivalent to running it at the end of the loop. (just after applying the status/action list changes)
+            // This order is required because this method needs to return the action updates.
             logger.debug(`MembershipManager applied action changes. Status: ${this.oldStatus} -> ${this.status}`);
+            if (this.oldStatus !== this.status) {
+                this.emit(MembershipManagerEvent.StatusChanged, this.oldStatus, this.status);
+            }
         }
         this.oldStatus = this.status;
         logger.debug(`MembershipManager before processing action. status=${this.oldStatus}`);
@@ -391,17 +366,16 @@ export class MembershipManager implements IMembershipManager {
 
     // LOOP HANDLER:
     private async membershipLoopHandler(type: MembershipActionType): Promise<ActionUpdate> {
-        this.oldStatus = this.status;
         switch (type) {
-            case MembershipActionType.SendFirstDelayedEvent: {
+            case MembershipActionType.SendDelayedEvent: {
                 // Before we start we check if we come from a state where we have a delay id.
                 if (!this.state.delayId) {
-                    return this.sendFirstDelayedLeaveEvent(); // Normal case without any previous delayed id.
+                    return this.sendOrResendDelayedLeaveEvent(); // Normal case without any previous delayed id.
                 } else {
                     // This can happen if someone else (or another client) removes our own membership event.
                     // It will trigger `onRTCSessionMemberUpdate` queue `MembershipActionType.SendFirstDelayedEvent`.
                     // We might still have our delayed event from the previous participation and dependent on the server this might not
-                    // get automatically removed if the state changes. Hence It would remove our membership unexpectedly shortly after the rejoin.
+                    // get removed automatically if the state changes. Hence, it would remove our membership unexpectedly shortly after the rejoin.
                     //
                     // In this block we will try to cancel this delayed event before setting up a new one.
 
@@ -411,17 +385,10 @@ export class MembershipManager implements IMembershipManager {
             case MembershipActionType.RestartDelayedEvent: {
                 if (!this.state.delayId) {
                     // Delay id got reset. This action was used to check if the hs canceled the delayed event when the join state got sent.
-                    return createInsertActionUpdate(
-                        this.state.hasMemberStateEvent
-                            ? MembershipActionType.SendMainDelayedEvent
-                            : MembershipActionType.SendFirstDelayedEvent,
-                    );
+                    return createInsertActionUpdate(MembershipActionType.SendDelayedEvent);
                 }
                 return this.restartDelayedEvent(this.state.delayId);
             }
-            case MembershipActionType.SendMainDelayedEvent: {
-                return this.sendMainDelayedEvent();
-            }
             case MembershipActionType.SendScheduledDelayedLeaveEvent: {
                 // We are already good
                 if (!this.state.hasMemberStateEvent) {
@@ -452,7 +419,11 @@ export class MembershipManager implements IMembershipManager {
     }
 
     // HANDLERS (used in the membershipLoopHandler)
-    private async sendFirstDelayedLeaveEvent(): Promise<ActionUpdate> {
+    private async sendOrResendDelayedLeaveEvent(): Promise<ActionUpdate> {
+        // We can reach this at the start of a call (where we do not yet have a membership: state.hasMemberStateEvent=false)
+        // or during a call if the state event canceled our delayed event or caused by an unexpected error that removed our delayed event.
+        // (Another client could have canceled it, the homeserver might have removed/lost it due to a restart, ...)
+        // In the `then` and `catch` block we treat both cases differently. "if (this.state.hasMemberStateEvent) {} else {}"
         return await this.client
             ._unstable_sendDelayedStateEvent(
                 this.room.roomId,
@@ -465,19 +436,37 @@ export class MembershipManager implements IMembershipManager {
             )
             .then((response) => {
                 // On success we reset retries and set delayId.
-                this.state.rateLimitRetries.set(MembershipActionType.SendFirstDelayedEvent, 0);
-                this.state.networkErrorRetries.set(MembershipActionType.SendFirstDelayedEvent, 0);
+                this.resetRateLimitCounter(MembershipActionType.SendDelayedEvent);
                 this.state.delayId = response.delay_id;
+                if (this.state.hasMemberStateEvent) {
+                    // This action was scheduled because the previous delayed event was cancelled
+                    // due to lack of https://github.com/element-hq/synapse/pull/17810
+                    return createInsertActionUpdate(
+                        MembershipActionType.RestartDelayedEvent,
+                        this.membershipKeepAlivePeriod,
+                    );
+                } else {
+                    // This action was scheduled because we are in the process of joining
                     return createInsertActionUpdate(MembershipActionType.SendJoinEvent);
+                }
             })
             .catch((e) => {
-                const repeatActionType = MembershipActionType.SendFirstDelayedEvent;
+                const repeatActionType = MembershipActionType.SendDelayedEvent;
                 if (this.manageMaxDelayExceededSituation(e)) {
                     return createInsertActionUpdate(repeatActionType);
                 }
                 const update = this.actionUpdateFromErrors(e, repeatActionType, "sendDelayedStateEvent");
                 if (update) return update;
 
+                if (this.state.hasMemberStateEvent) {
+                    // This action was scheduled because the previous delayed event was cancelled
+                    // due to lack of https://github.com/element-hq/synapse/pull/17810
+
+                    // Don't do any other delayed event work if its not supported.
+                    if (this.isUnsupportedDelayedEndpoint(e)) return {};
+                    throw Error("Could not send delayed event, even though delayed events are supported. " + e);
+                } else {
+                    // This action was scheduled because we are in the process of joining
                     // log and fall through
                     if (this.isUnsupportedDelayedEndpoint(e)) {
                         logger.info("Not using delayed event because the endpoint is not supported");
@@ -486,6 +475,7 @@ export class MembershipManager implements IMembershipManager {
                     }
                     // On any other error we fall back to not using delayed events and send the join state event immediately
                     return createInsertActionUpdate(MembershipActionType.SendJoinEvent);
+                }
             });
     }
 
@@ -495,11 +485,11 @@ export class MembershipManager implements IMembershipManager {
             ._unstable_updateDelayedEvent(delayId, UpdateDelayedEventAction.Cancel)
             .then(() => {
                 this.state.delayId = undefined;
-                this.resetRateLimitCounter(MembershipActionType.SendFirstDelayedEvent);
-                return createReplaceActionUpdate(MembershipActionType.SendFirstDelayedEvent);
+                this.resetRateLimitCounter(MembershipActionType.SendDelayedEvent);
+                return createReplaceActionUpdate(MembershipActionType.SendDelayedEvent);
             })
             .catch((e) => {
-                const repeatActionType = MembershipActionType.SendFirstDelayedEvent;
+                const repeatActionType = MembershipActionType.SendDelayedEvent;
                 const update = this.actionUpdateFromErrors(e, repeatActionType, "updateDelayedEvent");
                 if (update) return update;
 
@@ -538,7 +528,7 @@ export class MembershipManager implements IMembershipManager {
                 const repeatActionType = MembershipActionType.RestartDelayedEvent;
                 if (this.isNotFoundError(e)) {
                     this.state.delayId = undefined;
-                    return createInsertActionUpdate(MembershipActionType.SendMainDelayedEvent);
+                    return createInsertActionUpdate(MembershipActionType.SendDelayedEvent);
                 }
                 // If the HS does not support delayed events we wont reschedule.
                 if (this.isUnsupportedDelayedEndpoint(e)) return {};
@@ -552,40 +542,6 @@ export class MembershipManager implements IMembershipManager {
             });
     }
 
-    private async sendMainDelayedEvent(): Promise<ActionUpdate> {
-        return await this.client
-            ._unstable_sendDelayedStateEvent(
-                this.room.roomId,
-                {
-                    delay: this.membershipServerSideExpiryTimeout,
-                },
-                EventType.GroupCallMemberPrefix,
-                {}, // leave event
-                this.stateKey,
-            )
-            .then((response) => {
-                this.state.delayId = response.delay_id;
-                this.resetRateLimitCounter(MembershipActionType.SendMainDelayedEvent);
-                return createInsertActionUpdate(
-                    MembershipActionType.RestartDelayedEvent,
-                    this.membershipKeepAlivePeriod,
-                );
-            })
-            .catch((e) => {
-                const repeatActionType = MembershipActionType.SendMainDelayedEvent;
-                // Don't do any other delayed event work if its not supported.
-                if (this.isUnsupportedDelayedEndpoint(e)) return {};
-
-                if (this.manageMaxDelayExceededSituation(e)) {
-                    return createInsertActionUpdate(repeatActionType);
-                }
-                const update = this.actionUpdateFromErrors(e, repeatActionType, "updateDelayedEvent");
-                if (update) return update;
-
-                throw Error("Could not send delayed event, even though delayed events are supported. " + e);
-            });
-    }
-
     private async sendScheduledDelayedLeaveEventOrFallbackToSendLeaveEvent(delayId: string): Promise<ActionUpdate> {
         return await this.client
             ._unstable_updateDelayedEvent(delayId, UpdateDelayedEventAction.Send)
@@ -887,9 +843,8 @@ export class MembershipManager implements IMembershipManager {
         if (actions.length === 1) {
             const { type } = actions[0];
             switch (type) {
-                case MembershipActionType.SendFirstDelayedEvent:
+                case MembershipActionType.SendDelayedEvent:
                 case MembershipActionType.SendJoinEvent:
-                case MembershipActionType.SendMainDelayedEvent:
                     return Status.Connecting;
                 case MembershipActionType.UpdateExpiry: // where no delayed events
                     return Status.Connected;
@@ -904,7 +859,7 @@ export class MembershipManager implements IMembershipManager {
             // normal state for connected with delayed events
             if (
                 (types.includes(MembershipActionType.RestartDelayedEvent) ||
-                    types.includes(MembershipActionType.SendMainDelayedEvent)) &&
+                    (types.includes(MembershipActionType.SendDelayedEvent) && this.state.hasMemberStateEvent)) &&
                 types.includes(MembershipActionType.UpdateExpiry)
             ) {
                 return Status.Connected;

src/matrixrtc/NewMembershipManagerActionScheduler.ts

@@ -73,7 +73,7 @@ export class ActionScheduler {
             return;
         }
         this.running = true;
-        this._actions = [{ ts: Date.now(), type: MembershipActionType.SendFirstDelayedEvent }];
+        this._actions = [{ ts: Date.now(), type: MembershipActionType.SendDelayedEvent }];
         try {
             while (this._actions.length > 0) {
                 // Sort so next (smallest ts) action is at the beginning
@@ -98,7 +98,7 @@ export class ActionScheduler {
                         `\nDate.now: "${Date.now()}`,
                     );
                     try {
-                        // `this.wakeup` can also be called and sets the `wakupUpdate` object while we are in the handler.
+                        // `this.wakeup` can also be called and sets the `wakeupUpdate` object while we are in the handler.
                         handlerResult = await this.membershipLoopHandler(nextAction.type as MembershipActionType);
                     } catch (e) {
                         throw Error(`The MembershipManager shut down because of the end condition: ${e}`);
@@ -125,7 +125,7 @@ export class ActionScheduler {
     }
 
     public initiateJoin(): void {
-        this.wakeup?.({ replace: [{ ts: Date.now(), type: MembershipActionType.SendFirstDelayedEvent }] });
+        this.wakeup?.({ replace: [{ ts: Date.now(), type: MembershipActionType.SendDelayedEvent }] });
     }
     public initiateLeave(): void {
         this.wakeup?.({ replace: [{ ts: Date.now(), type: MembershipActionType.SendScheduledDelayedLeaveEvent }] });

src/matrixrtc/index.ts

@@ -20,3 +20,4 @@ export * from "./LivekitFocus.ts";
 export * from "./MatrixRTCSession.ts";
 export * from "./MatrixRTCSessionManager.ts";
 export type * from "./types.ts";
+export { Status, MembershipManagerEvent } from "./types.ts";

src/matrixrtc/types.ts

@@ -13,7 +13,10 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
-import { type IMentions } from "../matrix.ts";
+import type { IMentions } from "../matrix.ts";
+import type { CallMembership } from "./CallMembership.ts";
+import type { Focus } from "./focus.ts";
+
 export interface EncryptionKeyEntry {
     index: number;
     key: string;
@@ -34,3 +37,83 @@ export interface ICallNotifyContent {
     "notify_type": CallNotifyType;
     "call_id": string;
 }
+
+export enum Status {
+    Disconnected = "Disconnected",
+    Connecting = "Connecting",
+    ConnectingFailed = "ConnectingFailed",
+    Connected = "Connected",
+    Reconnecting = "Reconnecting",
+    Disconnecting = "Disconnecting",
+    Stuck = "Stuck",
+    Unknown = "Unknown",
+}
+
+export enum MembershipManagerEvent {
+    StatusChanged = "StatusChanged",
+}
+
+export type MembershipManagerEventHandlerMap = {
+    [MembershipManagerEvent.StatusChanged]: (prefStatus: Status, newStatus: Status) => void;
+};
+
+/**
+ * This interface defines what a MembershipManager uses and exposes.
+ * This interface is what we use to write tests and allows changing the actual implementation
+ * without breaking tests because of some internal method renaming.
+ *
+ * @internal
+ */
+export interface IMembershipManager {
+    /**
+     * If we are trying to join, or have successfully joined the session.
+     * It does not reflect if the room state is already configured to represent us being joined.
+     * It only means that the Manager should be trying to connect or to disconnect running.
+     * The Manager is still running right after isJoined becomes false to send the disconnect events.
+     * @returns true if we intend to be participating in the MatrixRTC session
+     * @deprecated This name is confusing and replaced by `isActivated()`. (Returns the same as `isActivated()`)
+     */
+    isJoined(): boolean;
+    /**
+     * If the manager is activated. This means it tries to do its job to join the call, resend state events...
+     * It does not imply that the room state is already configured to represent being joined.
+     * It means that the Manager tries to connect or is connected. ("the manager is still active")
+     * Once `leave()` is called the manager is not activated anymore but still running until `leave()` resolves.
+     * @returns `true` if we intend to be participating in the MatrixRTC session
+     */
+    isActivated(): boolean;
+    /**
+     * Get the actual connection status of the manager.
+     */
+    get status(): Status;
+    /**
+     * The current status while the manager is activated
+     */
+    /**
+     * Start sending all necessary events to make this user participate in the RTC session.
+     * @param fociPreferred the list of preferred foci to use in the joined RTC membership event.
+     * @param fociActive the active focus to use in the joined RTC membership event.
+     * @throws can throw if it exceeds a configured maximum retry.
+     */
+    join(fociPreferred: Focus[], fociActive?: Focus, onError?: (error: unknown) => void): void;
+    /**
+     * Send all necessary events to make this user leave the RTC session.
+     * @param timeout the maximum duration in ms until the promise is forced to resolve.
+     * @returns It resolves with true in case the leave was sent successfully.
+     * It resolves with false in case we hit the timeout before sending successfully.
+     */
+    leave(timeout?: number): Promise<boolean>;
+    /**
+     * Call this if the MatrixRTC session members have changed.
+     */
+    onRTCSessionMemberUpdate(memberships: CallMembership[]): Promise<void>;
+    /**
+     * The used active focus in the currently joined session.
+     * @returns the used active focus in the currently joined session or undefined if not joined.
+     */
+    getActiveFocus(): Focus | undefined;
+
+    // TypedEventEmitter methods:
+    on(event: MembershipManagerEvent.StatusChanged, listener: (oldStatus: Status, newStatus: Status) => void): this;
+    off(event: MembershipManagerEvent.StatusChanged, listener: (oldStatus: Status, newStatus: Status) => void): this;
+}