new: add playback state handling across platforms and integrate main play action in PlayerScreen

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

@@ -1,26 +1,35 @@
 package fr.ajaury.gwenedeg.player.ui
 
+import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import fr.ajaury.gwenedeg.player.PlaybackState
+import fr.ajaury.gwenedeg.player.ui.viewmodel.PlayerUiState
 import fr.ajaury.gwenedeg.player.ui.viewmodel.PlayerViewModel
-import org.jetbrains.compose.resources.ExperimentalResourceApi
+import fr.ajaury.gwenedeg.theme.GwenedegTheme
 import org.koin.compose.viewmodel.koinViewModel
 
-@OptIn(ExperimentalResourceApi::class)
 @Composable
 fun PlayerScreen(
     recordTitle: String,
     viewModel: PlayerViewModel = koinViewModel(),
 ) {
+    val uiState by viewModel.uiState.collectAsStateWithLifecycle()
+
     DisposableEffect(Unit) {
         viewModel.play(filePath = "files/demat.ogg")
         onDispose {
@@ -28,6 +37,19 @@ fun PlayerScreen(
         }
     }
 
+    PlayerScreen(
+        recordTitle = recordTitle,
+        uiState = uiState,
+        onMainPlayActionButtonClicked = viewModel::performMainPlayAction,
+    )
+}
+
+@Composable
+fun PlayerScreen(
+    recordTitle: String,
+    uiState: PlayerUiState,
+    onMainPlayActionButtonClicked: () -> Unit,
+) {
     Scaffold { innerPadding ->
         Box(
             modifier = Modifier
@@ -35,12 +57,62 @@ fun PlayerScreen(
                 .fillMaxSize(),
             contentAlignment = Alignment.Center,
         ) {
-            Column(horizontalAlignment = Alignment.CenterHorizontally) {
+            Column(
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.spacedBy(24.dp),
+            ) {
                 Text(
                     text = "Playing: $recordTitle",
                     style = MaterialTheme.typography.headlineMedium,
                 )
+
+                Button(onClick = onMainPlayActionButtonClicked) {
+                    Text(text = uiState.playbackState.toActionLabel())
+                }
             }
         }
     }
 }
+
+private fun PlaybackState.toActionLabel(): String =
+    when (this) {
+        PlaybackState.PLAYING -> "Pause"
+        PlaybackState.ENDED -> "Replay"
+        PlaybackState.PAUSED, PlaybackState.IDLE -> "Play"
+    }
+
+@Preview
+@Composable
+private fun PlayerScreenPlayingPreview() {
+    GwenedegTheme {
+        PlayerScreen(
+            recordTitle = "Demat",
+            uiState = PlayerUiState(playbackState = PlaybackState.PLAYING),
+            onMainPlayActionButtonClicked = {},
+        )
+    }
+}
+
+@Preview
+@Composable
+private fun PlayerScreenPausedPreview() {
+    GwenedegTheme {
+        PlayerScreen(
+            recordTitle = "Demat",
+            uiState = PlayerUiState(playbackState = PlaybackState.PAUSED),
+            onMainPlayActionButtonClicked = {},
+        )
+    }
+}
+
+@Preview
+@Composable
+private fun PlayerScreenEndedPreview() {
+    GwenedegTheme {
+        PlayerScreen(
+            recordTitle = "Demat",
+            uiState = PlayerUiState(playbackState = PlaybackState.ENDED),
+            onMainPlayActionButtonClicked = {},
+        )
+    }
+}

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

@@ -0,0 +1,7 @@
+package fr.ajaury.gwenedeg.player.ui.viewmodel
+
+import fr.ajaury.gwenedeg.player.PlaybackState
+
+data class PlayerUiState(
+    val playbackState: PlaybackState = PlaybackState.IDLE,
+)

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

@@ -1,25 +1,48 @@
 package fr.ajaury.gwenedeg.player.ui.viewmodel
 
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
 import fr.ajaury.gwenedeg.player.AudioPlayer
 import fr.ajaury.gwenedeg.player.AudioSessionManager
+import fr.ajaury.gwenedeg.player.PlaybackState
 import gwenedeg.shared.generated.resources.Res
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.WhileSubscribed
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlin.time.Duration.Companion.seconds
 
 class PlayerViewModel(
     private val audioPlayer: AudioPlayer,
     private val audioSessionManager: AudioSessionManager,
 ) : ViewModel() {
+    private var filePath: String? = null
+
+    val uiState: StateFlow<PlayerUiState> = audioPlayer.playbackState
+        .map { PlayerUiState(playbackState = it) }
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5.seconds),
+            initialValue = PlayerUiState(),
+        )
+
     init {
         audioSessionManager.activate()
     }
 
     fun play(filePath: String) {
+        this.filePath = filePath
         audioPlayer.load(uri = Res.getUri(filePath))
         audioPlayer.play()
     }
 
-    fun pause() {
-        audioPlayer.pause()
+    fun performMainPlayAction() {
+        when (uiState.value.playbackState) {
+            PlaybackState.PLAYING -> audioPlayer.pause()
+            PlaybackState.ENDED -> filePath?.let { play(it) }
+            PlaybackState.PAUSED, PlaybackState.IDLE -> audioPlayer.play()
+        }
     }
 
     fun stop() {