refactor: use SSoT for playback speed

data/playback/build.gradle.kts

@@ -11,10 +11,12 @@ kotlin {
         commonMain.dependencies {
             // Core modules
             implementation(projects.core.audioplayer)
+            implementation(projects.core.coroutines)
             implementation(projects.core.logging)
             implementation(projects.core.model)
 
             // Data modules
+            implementation(projects.data.preferences)
             implementation(projects.data.records)
             implementation(projects.data.resources)
             implementation(projects.data.subtitle)

data/playback/src/commonMain/kotlin/fr/ajaury/gwenedeg/player/data/PlaybackRepositoryImpl.kt

@@ -1,5 +1,6 @@
 package fr.ajaury.gwenedeg.player.data
 
+import fr.ajaury.gwenedeg.core.coroutines.domain.DispatcherProvider
 import fr.ajaury.gwenedeg.core.logging.domain.Logger
 import fr.ajaury.gwenedeg.core.model.Phrase
 import fr.ajaury.gwenedeg.player.domain.AudioPlayer
@@ -7,12 +8,16 @@ import fr.ajaury.gwenedeg.player.domain.PlaybackRepository
 import fr.ajaury.gwenedeg.player.model.PlaybackState
 import fr.ajaury.gwenedeg.player.model.PlaybackTiming
 import fr.ajaury.gwenedeg.player.model.PlayerState
+import fr.ajaury.gwenedeg.preferences.domain.PreferencesRepository
 import fr.ajaury.gwenedeg.records.model.Record
 import fr.ajaury.gwenedeg.resources.domain.ResourceReader
 import fr.ajaury.gwenedeg.subtitle.domain.GetCurrentSubtitleIndexUseCase
 import fr.ajaury.gwenedeg.subtitle.domain.SubtitleRepository
 import fr.ajaury.gwenedeg.subtitle.model.Subtitle
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -22,6 +27,7 @@ import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.launch
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.milliseconds
 import kotlin.time.Duration.Companion.seconds
@@ -30,9 +36,15 @@ internal class PlaybackRepositoryImpl(
     private val audioPlayer: AudioPlayer,
     private val resourceReader: ResourceReader,
     private val subtitleRepository: SubtitleRepository,
+    private val preferencesRepository: PreferencesRepository,
     private val getCurrentSubtitleIndex: GetCurrentSubtitleIndexUseCase,
+    private val dispatcherProvider: DispatcherProvider,
     private val logger: Logger,
 ) : PlaybackRepository {
+    // Audio operations must run on the main thread (e.g. ExoPlayer), so keep the scope on it.
+    private val scope = CoroutineScope(SupervisorJob() + dispatcherProvider.main)
+    private var speedObservationJob: Job? = null
+
     private val recordTitle = MutableStateFlow(Phrase(transcription = ""))
     private val subtitle = MutableStateFlow(Subtitle(emptyList()))
 
@@ -91,6 +103,17 @@ internal class PlaybackRepositoryImpl(
         playAudio(filePath = record.audioResourcePath)
         subtitle.value = loadSubtitle(record = record)
         recordTitle.value = record.title
+
+        observePlaybackSpeed()
+    }
+
+    private fun observePlaybackSpeed() {
+        speedObservationJob?.cancel()
+        speedObservationJob = scope.launch {
+            preferencesRepository.playbackPreferences.collect { playbackPreferences ->
+                setSpeed(speed = playbackPreferences.speed)
+            }
+        }
     }
 
     private fun playAudio(filePath: String) {
@@ -136,7 +159,7 @@ internal class PlaybackRepositoryImpl(
         audioPlayer.seekTo(position)
     }
 
-    override fun setSpeed(speed: Float) {
+    private fun setSpeed(speed: Float) {
         audioPlayer.setSpeed(speed)
     }
 

data/playback/src/commonMain/kotlin/fr/ajaury/gwenedeg/player/domain/PlaybackRepository.kt

@@ -25,8 +25,6 @@ interface PlaybackRepository {
 
     fun seekTo(position: Duration)
 
-    fun setSpeed(speed: Float)
-
     fun seekToSentence(sentenceIndex: Int)
 
     fun goToPreviousSentence()

shared/src/commonMain/kotlin/fr/ajaury/gwenedeg/player/ui/viewmodel/PlayerViewModel.kt

@@ -62,7 +62,6 @@ class PlayerViewModel(
             if (alreadyLoadedRecord != null) {
                 logger.debug("Record $recordId already loaded")
                 playbackRepository.load(record = alreadyLoadedRecord)
-                applyCurrentSpeed()
                 return@launch
             }
 
@@ -73,16 +72,10 @@ class PlayerViewModel(
             }
 
             playbackRepository.load(record = loadedRecord)
-            applyCurrentSpeed()
             record.value = loadedRecord
         }
     }
 
-    private suspend fun applyCurrentSpeed() {
-        val playbackPreferences = preferencesRepository.playbackPreferences.firstOrNull() ?: return
-        playbackRepository.setSpeed(playbackPreferences.speed)
-    }
-
     fun performMainPlayAction() {
         when (uiState.value.playerState.playbackState) {
             PlaybackState.PLAYING -> playbackRepository.pause()
@@ -113,9 +106,9 @@ class PlayerViewModel(
             PlaybackPreferences.MIN_SPEED,
             PlaybackPreferences.MAX_SPEED,
         )
+
         viewModelScope.launch {
             preferencesRepository.setPlaybackSpeed(clampedSpeed)
-            playbackRepository.setSpeed(clampedSpeed)
         }
     }