move HomeserverConnected

src/state/CallViewModel/localMember/HomeserverConnected.ts

@@ -0,0 +1,85 @@
+/*
+Copyright 2025 Element Creations Ltd.
+Copyright 2024 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import {
+  MembershipManagerEvent,
+  Status,
+  type MatrixRTCSession,
+} from "matrix-js-sdk/lib/matrixrtc";
+import { ClientEvent, type MatrixClient, SyncState } from "matrix-js-sdk";
+import { fromEvent, startWith, map, tap, type Observable } from "rxjs";
+import { logger as rootLogger } from "matrix-js-sdk/lib/logger";
+
+import { type ObservableScope } from "../../ObservableScope";
+import { type Behavior } from "../../Behavior";
+import { and$ } from "../../../utils/observable";
+import { type NodeStyleEventEmitter } from "../../../utils/test";
+
+/**
+ * Logger instance (scoped child) for homeserver connection updates.
+ */
+const logger = rootLogger.getChild("[HomeserverConnected]");
+
+/**
+ * Behavior representing whether we consider ourselves connected to the Matrix homeserver
+ * for the purposes of a MatrixRTC session.
+ *
+ * Becomes FALSE if ANY sub-condition is fulfilled:
+ * 1. Sync loop is not in SyncState.Syncing
+ * 2. membershipStatus !== Status.Connected
+ * 3. probablyLeft === true
+ */
+export function createHomeserverConnected$(
+  scope: ObservableScope,
+  client: NodeStyleEventEmitter & Pick<MatrixClient, "getSyncState">,
+  matrixRTCSession: NodeStyleEventEmitter &
+    Pick<MatrixRTCSession, "membershipStatus" | "probablyLeft">,
+): Behavior<boolean> {
+  const syncing$ = (
+    fromEvent(client, ClientEvent.Sync) as Observable<[SyncState]>
+  ).pipe(
+    startWith([client.getSyncState()]),
+    map(([state]) => state === SyncState.Syncing),
+  );
+
+  const membershipConnected$ = fromEvent(
+    matrixRTCSession,
+    MembershipManagerEvent.StatusChanged,
+  ).pipe(
+    startWith(null),
+    map(() => matrixRTCSession.membershipStatus === Status.Connected),
+  );
+
+  // This is basically notProbablyLeft$
+  //
+  // probablyLeft is computed by a local timer that mimics the server delayed event.
+  // If we locally predict our server event timed out. We consider ourselves as probablyLeft
+  // even though we might not yet have received the delayed event leave.
+  //
+  // If that is not the case we certainly still have a valid membership on the matrix network
+  // independet if the sync currently works.
+  const certainlyConnected$ = fromEvent(
+    matrixRTCSession,
+    MembershipManagerEvent.ProbablyLeft,
+  ).pipe(
+    startWith(null),
+    map(() => matrixRTCSession.probablyLeft !== true),
+  );
+
+  const connectedCombined$ = and$(
+    syncing$,
+    membershipConnected$,
+    certainlyConnected$,
+  ).pipe(
+    tap((connected) => {
+      logger.info(`Homeserver connected update: ${connected}`);
+    }),
+  );
+
+  return scope.behavior(connectedCombined$);
+}