Audio device controls for mobile native audio device selection

Backport of 0971a15c40.

src/controls.ts

@@ -5,15 +5,55 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-import { Subject } from "rxjs";
+import { BehaviorSubject, Subject } from "rxjs";
 
 export interface Controls {
-  canEnterPip: () => boolean;
-  enablePip: () => void;
-  disablePip: () => void;
+  canEnterPip(): boolean;
+  enablePip(): void;
+  disablePip(): void;
+  /** @deprecated use  setAvailableAudioDevices instead*/
+  setAvailableOutputDevices(devices: OutputDevice[]): void;
+  setAvailableAudioDevices(devices: OutputDevice[]): void;
+  /** @deprecated use  setAudioDevice instead*/
+  setOutputDevice(id: string): void;
+  setAudioDevice(id: string): void;
+  /** @deprecated use  onAudioDeviceSelect instead*/
+  onOutputDeviceSelect?: (id: string) => void;
+  onAudioDeviceSelect?: (id: string) => void;
+  /** @deprecated use  setAudioEnabled instead*/
+  setOutputEnabled(enabled: boolean): void;
+  setAudioEnabled(enabled: boolean): void;
+  /** @deprecated use  showNativeAudioDevicePicker instead*/
+  showNativeOutputDevicePicker?: () => void;
+  showNativeAudioDevicePicker?: () => void;
 }
 
+export interface OutputDevice {
+  id: string;
+  name: string;
+  forEarpiece?: boolean;
+  isEarpiece?: boolean;
+  isSpeaker?: boolean;
+  isExternalHeadset?: boolean;
+}
+
+/**
+ * If pipMode is enabled, EC will render a adapted call view layout.
+ */
 export const setPipEnabled$ = new Subject<boolean>();
+// BehaviorSubject since the client might set this before we have subscribed (GroupCallView still in "loading" state)
+// We want the devices that have been set during loading to be available immediately once loaded.
+export const availableOutputDevices$ = new BehaviorSubject<OutputDevice[]>([]);
+// BehaviorSubject since the client might set this before we have subscribed (GroupCallView still in "loading" state)
+// We want the device that has been set during loading to be available immediately once loaded.
+export const outputDevice$ = new BehaviorSubject<string | undefined>(undefined);
+/**
+ * This allows the os to mute the call if the user
+ * presses the volume down button when it is at the minimum volume.
+ *
+ * This should also be used to display a darkened overlay screen letting the user know that audio is muted.
+ */
+export const setAudioEnabled$ = new Subject<boolean>();
 
 window.controls = {
   canEnterPip(): boolean {
@@ -27,4 +67,28 @@ window.controls = {
     if (!setPipEnabled$.observed) throw new Error("No call is running");
     setPipEnabled$.next(false);
   },
+  setAvailableAudioDevices(devices: OutputDevice[]): void {
+    availableOutputDevices$.next(devices);
+  },
+  setAudioDevice(id: string): void {
+    outputDevice$.next(id);
+  },
+  setAudioEnabled(enabled: boolean): void {
+    if (!setAudioEnabled$.observed)
+      throw new Error(
+        "Output controls are disabled. No setAudioEnabled$ observer",
+      );
+    setAudioEnabled$.next(enabled);
+  },
+
+  // wrappers for the deprecated controls fields
+  setOutputEnabled(enabled: boolean): void {
+    this.setAudioEnabled(enabled);
+  },
+  setAvailableOutputDevices(devices: OutputDevice[]): void {
+    this.setAvailableAudioDevices(devices);
+  },
+  setOutputDevice(id: string): void {
+    this.setAudioDevice(id);
+  },
 };