new: show previous and next subtitles

shared/src/commonMain/kotlin/fr/ajaury/gwenedeg/di/Modules.kt

@@ -8,7 +8,7 @@ import fr.ajaury.gwenedeg.records.domain.RecordRepository
 import fr.ajaury.gwenedeg.records.ui.viewmodel.RecordsViewModel
 import fr.ajaury.gwenedeg.subtitle.data.LrcParser
 import fr.ajaury.gwenedeg.subtitle.data.LrcSubtitleRepository
-import fr.ajaury.gwenedeg.subtitle.domain.GetSubtitleTextUseCase
+import fr.ajaury.gwenedeg.subtitle.domain.GetSubtitleWindowUseCase
 import fr.ajaury.gwenedeg.subtitle.domain.SubtitleRepository
 import org.koin.core.module.dsl.bind
 import org.koin.core.module.dsl.factoryOf
@@ -20,7 +20,7 @@ val sharedModule = module {
     factoryOf(::InMemoryRecordRepository) { bind<RecordRepository>() }
     factoryOf(::LrcParser)
     factoryOf(::LrcSubtitleRepository) { bind<SubtitleRepository>() }
-    factoryOf(::GetSubtitleTextUseCase)
+    factoryOf(::GetSubtitleWindowUseCase)
     viewModelOf(::RecordsViewModel)
     viewModelOf(::PlayerViewModel)
 }

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

@@ -31,7 +31,9 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
@@ -39,6 +41,7 @@ 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 fr.ajaury.gwenedeg.subtitle.domain.SubtitleWindow
 import fr.ajaury.gwenedeg.theme.GwenedegTheme
 import org.koin.compose.viewmodel.koinViewModel
 
@@ -81,7 +84,12 @@ fun PlayerScreen(
     Scaffold(
         topBar = {
             TopAppBar(
-                title = {},
+                title = {
+                    Text(
+                        text = recordTitle,
+                        style = MaterialTheme.typography.headlineSmall,
+                    )
+                },
                 navigationIcon = {
                     IconButton(onClick = onBackClicked) {
                         Icon(
@@ -101,53 +109,105 @@ fun PlayerScreen(
             contentAlignment = Alignment.Center,
         ) {
             Column(
+                modifier = Modifier.fillMaxSize(),
                 horizontalAlignment = Alignment.CenterHorizontally,
-                verticalArrangement = Arrangement.spacedBy(24.dp),
+                verticalArrangement = Arrangement.SpaceBetween,
             ) {
-                Text(
-                    text = "Playing: $recordTitle",
-                    style = MaterialTheme.typography.headlineMedium,
+                Spacer(Modifier)
+
+                Subtitles(
+                    uiState = uiState,
                 )
 
-                Spacer(modifier = Modifier.weight(1f))
-
-                Text(
-                    text = uiState.subtitle,
-                    style = MaterialTheme.typography.titleLarge,
-                    textAlign = TextAlign.Center,
-                    modifier = Modifier.fillMaxWidth(),
+                PlayerState(
+                    uiState = uiState,
+                    onSeek = onSeek,
+                    onMainPlayActionButtonClicked = onMainPlayActionButtonClicked,
                 )
-
-                var seekProgress by remember { mutableStateOf<Float?>(null) }
-                Slider(
-                    value = seekProgress ?: uiState.progress,
-                    onValueChange = { seekProgress = it },
-                    onValueChangeFinished = {
-                        seekProgress?.let { fraction ->
-                            if (uiState.durationMs > 0) {
-                                onSeek(fraction)
-                            }
-                        }
-                        seekProgress = null
-                    },
-                    modifier = Modifier.fillMaxWidth(),
-                )
-
-                Button(
-                    modifier = Modifier.size(60.dp),
-                    contentPadding = PaddingValues(0.dp),
-                    onClick = onMainPlayActionButtonClicked,
-                ) {
-                    Icon(
-                        imageVector = uiState.playbackState.toActionIcon(),
-                        contentDescription = uiState.playbackState.toActionContentDescription(),
-                    )
-                }
             }
         }
     }
 }
 
+@Composable
+private fun Subtitles(uiState: PlayerUiState) {
+    Column(
+        modifier = Modifier.fillMaxWidth(),
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        Subtitle(
+            text = uiState.subtitles.previous,
+            style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.5f),
+        )
+        Subtitle(
+            text = uiState.subtitles.current,
+            style = MaterialTheme.typography.headlineSmall,
+            color = Color.Unspecified,
+        )
+        Subtitle(
+            text = uiState.subtitles.next,
+            style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.5f),
+        )
+    }
+}
+
+@Composable
+private fun Subtitle(
+    text: String,
+    style: TextStyle,
+    color: Color,
+) {
+    Text(
+        text = text,
+        style = style,
+        color = color,
+        textAlign = TextAlign.Center,
+        modifier = Modifier.fillMaxWidth(),
+    )
+}
+
+@Composable
+private fun PlayerState(
+    uiState: PlayerUiState,
+    onSeek: (Float) -> Unit,
+    onMainPlayActionButtonClicked: () -> Unit,
+) {
+    Column(
+        modifier = Modifier.fillMaxWidth(),
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        var seekProgress by remember { mutableStateOf<Float?>(null) }
+        Slider(
+            value = seekProgress ?: uiState.progress,
+            onValueChange = { seekProgress = it },
+            onValueChangeFinished = {
+                seekProgress?.let { fraction ->
+                    if (uiState.durationMs > 0) {
+                        onSeek(fraction)
+                    }
+                }
+                seekProgress = null
+            },
+            modifier = Modifier.fillMaxWidth(),
+        )
+
+        Button(
+            modifier = Modifier.size(60.dp),
+            contentPadding = PaddingValues(0.dp),
+            onClick = onMainPlayActionButtonClicked,
+        ) {
+            Icon(
+                imageVector = uiState.playbackState.toActionIcon(),
+                contentDescription = uiState.playbackState.toActionContentDescription(),
+            )
+        }
+    }
+}
+
 private fun PlaybackState.toActionIcon(): ImageVector =
     when (this) {
         PlaybackState.PLAYING -> Icons.Default.Pause
@@ -168,7 +228,16 @@ private fun PlayerScreenPlayingPreview() {
     GwenedegTheme {
         PlayerScreen(
             recordTitle = "Demat",
-            uiState = PlayerUiState(playbackState = PlaybackState.PLAYING, positionMs = 1234, durationMs = 5000, subtitle = "Demat deoc'h !"),
+            uiState = PlayerUiState(
+                playbackState = PlaybackState.PLAYING,
+                positionMs = 1234,
+                durationMs = 5000,
+                subtitles = SubtitleWindow(
+                    previous = "Demat deoc'h !",
+                    current = "Kenavo !",
+                    next = "Kenavo emberr !",
+                ),
+            ),
             onMainPlayActionButtonClicked = {},
             onSeek = {},
             onBackClicked = {},
@@ -182,7 +251,16 @@ private fun PlayerScreenPausedPreview() {
     GwenedegTheme {
         PlayerScreen(
             recordTitle = "Demat",
-            uiState = PlayerUiState(playbackState = PlaybackState.PAUSED, positionMs = 1234, durationMs = 5000, subtitle = "Demat deoc'h !"),
+            uiState = PlayerUiState(
+                playbackState = PlaybackState.PAUSED,
+                positionMs = 1234,
+                durationMs = 5000,
+                subtitles = SubtitleWindow(
+                    previous = "Demat deoc'h !",
+                    current = "Kenavo !",
+                    next = "Kenavo emberr !",
+                ),
+            ),
             onMainPlayActionButtonClicked = {},
             onSeek = {},
             onBackClicked = {},
@@ -196,7 +274,16 @@ private fun PlayerScreenEndedPreview() {
     GwenedegTheme {
         PlayerScreen(
             recordTitle = "Demat",
-            uiState = PlayerUiState(playbackState = PlaybackState.ENDED, positionMs = 1234, durationMs = 5000, subtitle = "Demat deoc'h !"),
+            uiState = PlayerUiState(
+                playbackState = PlaybackState.ENDED,
+                positionMs = 1234,
+                durationMs = 5000,
+                subtitles = SubtitleWindow(
+                    previous = "Demat deoc'h !",
+                    current = "Kenavo !",
+                    next = "Kenavo emberr !",
+                ),
+            ),
             onMainPlayActionButtonClicked = {},
             onSeek = {},
             onBackClicked = {},

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

@@ -1,12 +1,13 @@
 package fr.ajaury.gwenedeg.player.ui.viewmodel
 
 import fr.ajaury.gwenedeg.player.PlaybackState
+import fr.ajaury.gwenedeg.subtitle.domain.SubtitleWindow
 
 data class PlayerUiState(
     val playbackState: PlaybackState = PlaybackState.IDLE,
     val positionMs: Long = 0L,
     val durationMs: Long = 0L,
-    val subtitle: String = "",
+    val subtitles: SubtitleWindow = SubtitleWindow(),
 ) {
     val progress: Float
         get() = if (durationMs > 0) (positionMs.toFloat() / durationMs).coerceIn(0f, 1f) else 0f

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

@@ -6,7 +6,7 @@ import fr.ajaury.gwenedeg.core.logging.Logger
 import fr.ajaury.gwenedeg.player.AudioPlayer
 import fr.ajaury.gwenedeg.player.AudioSessionManager
 import fr.ajaury.gwenedeg.player.PlaybackState
-import fr.ajaury.gwenedeg.subtitle.domain.GetSubtitleTextUseCase
+import fr.ajaury.gwenedeg.subtitle.domain.GetSubtitleWindowUseCase
 import fr.ajaury.gwenedeg.subtitle.domain.Subtitle
 import fr.ajaury.gwenedeg.subtitle.domain.SubtitleRepository
 import gwenedeg.shared.generated.resources.Res
@@ -29,7 +29,7 @@ class PlayerViewModel(
     private val audioPlayer: AudioPlayer,
     private val audioSessionManager: AudioSessionManager,
     private val subtitleRepository: SubtitleRepository,
-    private val getSubtitleText: GetSubtitleTextUseCase,
+    private val getSubtitleWindow: GetSubtitleWindowUseCase,
     private val logger: Logger,
 ) : ViewModel() {
     private var filePath: String? = null
@@ -62,7 +62,10 @@ class PlayerViewModel(
             playbackState = playbackState,
             positionMs = currentPosition.inWholeMilliseconds,
             durationMs = audioPlayer.duration.inWholeMilliseconds,
-            subtitle = getSubtitleText(subtitle, currentPosition.inWholeMilliseconds),
+            subtitles = getSubtitleWindow(
+                subtitle = subtitle,
+                progressMs = currentPosition.inWholeMilliseconds,
+            ),
         )
     }.stateIn(
         scope = viewModelScope,
@@ -90,7 +93,10 @@ class PlayerViewModel(
                 try {
                     subtitleRepository.getSubtitle(resourcePath)
                 } catch (exception: Exception) {
-                    logger.error(message = "Failed to load subtitle: $resourcePath", throwable = exception)
+                    logger.error(
+                        message = "Failed to load subtitle: $resourcePath",
+                        throwable = exception,
+                    )
                     Subtitle(emptyList())
                 }
         }

shared/src/commonMain/kotlin/fr/ajaury/gwenedeg/subtitle/domain/GetSubtitleTextUseCase.kt

@@ -1,16 +0,0 @@
-package fr.ajaury.gwenedeg.subtitle.domain
-
-/**
- * Resolves the subtitle text to display for a given playback progress: the latest cue whose start
- * is at or before [progressMs], or `null` when no cue has started yet.
- */
-class GetSubtitleTextUseCase {
-    operator fun invoke(
-        subtitle: Subtitle,
-        progressMs: Long,
-    ): String =
-        subtitle.lines
-            .lastOrNull { it.startMs <= progressMs }
-            ?.text
-            .orEmpty()
-}

shared/src/commonMain/kotlin/fr/ajaury/gwenedeg/subtitle/domain/GetSubtitleWindowUseCase.kt

@@ -0,0 +1,16 @@
+package fr.ajaury.gwenedeg.subtitle.domain
+
+class GetSubtitleWindowUseCase {
+    operator fun invoke(
+        subtitle: Subtitle,
+        progressMs: Long,
+    ): SubtitleWindow {
+        val lines = subtitle.lines
+        val currentIndex = lines.indexOfLast { it.startMs <= progressMs }
+        return SubtitleWindow(
+            previous = lines.getOrNull(currentIndex - 1)?.text.orEmpty(),
+            current = lines.getOrNull(currentIndex)?.text.orEmpty(),
+            next = lines.getOrNull(currentIndex + 1)?.text.orEmpty(),
+        )
+    }
+}

shared/src/commonMain/kotlin/fr/ajaury/gwenedeg/subtitle/domain/SubtitleWindow.kt

@@ -0,0 +1,7 @@
+package fr.ajaury.gwenedeg.subtitle.domain
+
+data class SubtitleWindow(
+    val previous: String = "",
+    val current: String = "",
+    val next: String = "",
+)

shared/src/commonTest/kotlin/fr/ajaury/gwenedeg/subtitle/GetSubtitleTextUseCaseTest.kt

@@ -1,45 +0,0 @@
-package fr.ajaury.gwenedeg.subtitle
-
-import fr.ajaury.gwenedeg.subtitle.domain.GetSubtitleTextUseCase
-import fr.ajaury.gwenedeg.subtitle.domain.Subtitle
-import fr.ajaury.gwenedeg.subtitle.domain.SubtitleLine
-import kotlin.test.Test
-import kotlin.test.assertEquals
-import kotlin.test.assertNull
-
-class GetSubtitleTextUseCaseTest {
-    private val getSubtitleText = GetSubtitleTextUseCase()
-
-    private val subtitle =
-        Subtitle(
-            lines =
-                listOf(
-                    SubtitleLine(startMs = 0, text = "Demat deoc'h !"),
-                    SubtitleLine(startMs = 4310, text = "Kenavo !"),
-                    SubtitleLine(startMs = 7350, text = "Kenavo emberr !"),
-                ),
-        )
-
-    @Test
-    fun returns_null_before_the_first_cue() {
-        assertEquals("", getSubtitleText(subtitle, progressMs = -1))
-    }
-
-    @Test
-    fun returns_the_active_cue_at_and_after_its_start() {
-        assertEquals("Demat deoc'h !", getSubtitleText(subtitle, progressMs = 0))
-        assertEquals("Demat deoc'h !", getSubtitleText(subtitle, progressMs = 4309))
-        assertEquals("Kenavo !", getSubtitleText(subtitle, progressMs = 4310))
-        assertEquals("Kenavo !", getSubtitleText(subtitle, progressMs = 5000))
-    }
-
-    @Test
-    fun returns_the_last_cue_past_the_end() {
-        assertEquals("Kenavo emberr !", getSubtitleText(subtitle, progressMs = 50_000))
-    }
-
-    @Test
-    fun returns_null_for_an_empty_subtitle() {
-        assertEquals("", getSubtitleText(Subtitle(emptyList()), progressMs = 1_000))
-    }
-}

shared/src/commonTest/kotlin/fr/ajaury/gwenedeg/subtitle/GetSubtitleWindowUseCaseTest.kt

@@ -0,0 +1,62 @@
+package fr.ajaury.gwenedeg.subtitle
+
+import fr.ajaury.gwenedeg.subtitle.domain.GetSubtitleWindowUseCase
+import fr.ajaury.gwenedeg.subtitle.domain.Subtitle
+import fr.ajaury.gwenedeg.subtitle.domain.SubtitleLine
+import fr.ajaury.gwenedeg.subtitle.domain.SubtitleWindow
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class GetSubtitleWindowUseCaseTest {
+    private val getSubtitleWindow = GetSubtitleWindowUseCase()
+
+    private val subtitle =
+        Subtitle(
+            lines =
+                listOf(
+                    SubtitleLine(startMs = 0, text = "Demat deoc'h !"),
+                    SubtitleLine(startMs = 4310, text = "Kenavo !"),
+                    SubtitleLine(startMs = 7350, text = "Kenavo emberr !"),
+                ),
+        )
+
+    @Test
+    fun before_the_first_cue_only_next_is_set() {
+        assertEquals(
+            SubtitleWindow(previous = "", current = "", next = "Demat deoc'h !"),
+            getSubtitleWindow(subtitle, progressMs = -1),
+        )
+    }
+
+    @Test
+    fun on_the_first_cue_there_is_no_previous() {
+        assertEquals(
+            SubtitleWindow(previous = "", current = "Demat deoc'h !", next = "Kenavo !"),
+            getSubtitleWindow(subtitle, progressMs = 0),
+        )
+    }
+
+    @Test
+    fun on_a_middle_cue_all_three_are_set() {
+        assertEquals(
+            SubtitleWindow(previous = "Demat deoc'h !", current = "Kenavo !", next = "Kenavo emberr !"),
+            getSubtitleWindow(subtitle, progressMs = 5000),
+        )
+    }
+
+    @Test
+    fun on_the_last_cue_there_is_no_next() {
+        assertEquals(
+            SubtitleWindow(previous = "Kenavo !", current = "Kenavo emberr !", next = ""),
+            getSubtitleWindow(subtitle, progressMs = 50_000),
+        )
+    }
+
+    @Test
+    fun an_empty_subtitle_yields_an_empty_window() {
+        assertEquals(
+            SubtitleWindow(),
+            getSubtitleWindow(Subtitle(emptyList()), progressMs = 1_000),
+        )
+    }
+}