finish recording gracefully when audio focus is lost

if something else grabs focus mid-recording (phone call, etc), stop
the recording and keep the partial result in preview state instead
of silently recording garbage

Signed-off-by: vmfunc <celeste@linux.com>

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/voicemessages/composer/DefaultVoiceMessageComposerPresenter.kt

@@ -249,7 +249,11 @@ class DefaultVoiceMessageComposerPresenter(
 
     private fun CoroutineScope.startRecording() = launch {
         try {
-            audioFocus.requestAudioFocus(AudioFocusRequester.RecordVoiceMessage) {}
+            audioFocus.requestAudioFocus(AudioFocusRequester.RecordVoiceMessage) {
+                // something else grabbed focus (phone call, etc) - finish gracefully
+                // so the user keeps their partial recording
+                sessionCoroutineScope.finishRecording()
+            }
             voiceRecorder.startRecord()
         } catch (e: SecurityException) {
             audioFocus.releaseAudioFocus()

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/voicemessages/composer/DefaultVoiceMessageComposerPresenterTest.kt

@@ -199,6 +199,30 @@ class DefaultVoiceMessageComposerPresenterTest {
         }
     }
 
+    @Test
+    fun `present - audio focus loss during recording finishes gracefully`() = runTest {
+        var onFocusLost: (() -> Unit)? = null
+        val testAudioFocus = FakeAudioFocus(
+            requestAudioFocusResult = { _, callback -> onFocusLost = callback },
+            releaseAudioFocusResult = { },
+        )
+        val presenter = createDefaultVoiceMessageComposerPresenter(audioFocus = testAudioFocus)
+        presenter.test {
+            awaitItem().eventSink(VoiceMessageComposerEvent.RecorderEvent(VoiceMessageRecorderEvent.Start))
+            awaitItem()
+
+            // simulate focus loss (phone call, etc)
+            onFocusLost?.invoke()
+            advanceUntilIdle()
+
+            val finalState = awaitItem()
+            assertThat(finalState.voiceMessageState).isEqualTo(aPreviewState())
+            voiceRecorder.assertCalls(started = 1, stopped = 1)
+
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
     @Test
     fun `present - abort recording`() = runTest {
         val presenter = createDefaultVoiceMessageComposerPresenter()
@@ -687,6 +711,7 @@ class DefaultVoiceMessageComposerPresenterTest {
     private fun TestScope.createDefaultVoiceMessageComposerPresenter(
         permissionsPresenter: PermissionsPresenter = createFakePermissionsPresenter(),
         voiceRecorder: VoiceRecorder = this@DefaultVoiceMessageComposerPresenterTest.voiceRecorder,
+        audioFocus: AudioFocus = this@DefaultVoiceMessageComposerPresenterTest.audioFocus,
     ): DefaultVoiceMessageComposerPresenter {
         return DefaultVoiceMessageComposerPresenter(
             sessionCoroutineScope = backgroundScope,