Split MediaViewModel into multiple files

src/state/media/observeRtpStreamStats.ts

@@ -0,0 +1,59 @@
+/*
+Copyright 2023, 2024 New Vector Ltd.
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import {
+  LocalTrack,
+  type Participant,
+  RemoteTrack,
+  type Track,
+} from "livekit-client";
+import {
+  combineLatest,
+  interval,
+  type Observable,
+  startWith,
+  switchMap,
+} from "rxjs";
+
+import { observeTrackReference$ } from "../observeTrackReference";
+
+export function observeRtpStreamStats$(
+  participant: Participant,
+  source: Track.Source,
+  type: "inbound-rtp" | "outbound-rtp",
+): Observable<
+  RTCInboundRtpStreamStats | RTCOutboundRtpStreamStats | undefined
+> {
+  return combineLatest([
+    observeTrackReference$(participant, source),
+    interval(1000).pipe(startWith(0)),
+  ]).pipe(
+    switchMap(async ([trackReference]) => {
+      const track = trackReference?.publication?.track;
+      if (
+        !track ||
+        !(track instanceof RemoteTrack || track instanceof LocalTrack)
+      ) {
+        return undefined;
+      }
+      const report = await track.getRTCStatsReport();
+      if (!report) {
+        return undefined;
+      }
+
+      for (const v of report.values()) {
+        if (v.type === type) {
+          return v;
+        }
+      }
+
+      return undefined;
+    }),
+    startWith(undefined),
+  );
+}