refactor(core/series): improve data loading reliability with concurrent initialization

app-tv/src/main/java/hu/bbara/purefin/ui/screen/series/TvSeriesScreen.kt

@@ -9,7 +9,6 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
-import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
@@ -18,13 +17,13 @@ import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.tv.material3.MaterialTheme
-import androidx.tv.material3.Text as TvText
 import hu.bbara.purefin.core.feature.content.series.SeriesViewModel
+import hu.bbara.purefin.core.navigation.SeriesDto
 import hu.bbara.purefin.model.Episode
 import hu.bbara.purefin.model.Season
 import hu.bbara.purefin.model.Series
-import hu.bbara.purefin.core.navigation.SeriesDto
 import hu.bbara.purefin.ui.common.media.MediaDetailHorizontalPadding
 import hu.bbara.purefin.ui.common.media.TvMediaDetailBodyBox
 import hu.bbara.purefin.ui.common.media.TvMediaDetailScaffold
@@ -35,6 +34,7 @@ import hu.bbara.purefin.ui.screen.series.components.TvSeasonTabs
 import hu.bbara.purefin.ui.screen.series.components.TvSeriesHeroSection
 import hu.bbara.purefin.ui.screen.waiting.PurefinWaitingScreen
 import java.util.UUID
+import androidx.tv.material3.Text as TvText
 
 @Composable
 fun TvSeriesScreen(
@@ -54,8 +54,8 @@ fun TvSeriesScreen(
     if (seriesData != null) {
         TvSeriesScreenContent(
             series = seriesData,
+            selectSeason = viewModel::selectSeason,
             onPlayEpisode = viewModel::onPlayEpisode,
-            onLoadSeasonEpisodes = viewModel::loadSeasonEpisodes,
             focusedSeasonId = focusedSeasonId,
             focusedEpisodeId = focusedEpisodeId,
             modifier = modifier
@@ -68,8 +68,8 @@ fun TvSeriesScreen(
 @Composable
 internal fun TvSeriesScreenContent(
     series: Series,
+    selectSeason: (UUID, UUID) -> Unit,
     onPlayEpisode: (UUID) -> Unit,
-    onLoadSeasonEpisodes: (UUID, UUID) -> Unit = { _, _ -> },
     focusedSeasonId: UUID? = null,
     focusedEpisodeId: UUID? = null,
     modifier: Modifier = Modifier,
@@ -96,7 +96,7 @@ internal fun TvSeriesScreenContent(
         initialFocusSeason.episodeCount > 0
 
     LaunchedEffect(series.id, selectedSeason?.id) {
-        selectedSeason?.let { onLoadSeasonEpisodes(series.id, it.id) }
+        selectedSeason?.let { selectSeason(series.id, it.id) }
     }
 
     TvMediaDetailScaffold(

app/src/main/java/hu/bbara/purefin/ui/screen/series/SeriesScreen.kt

@@ -99,6 +99,7 @@ fun SeriesScreen(
 
         SeriesScreenInternal(
             series = seriesData,
+            selectSeason = viewModel::selectSeason,
             seriesDownloadState = seriesDownloadState,
             seasonDownloadState = seasonDownloadState,
             isSmartDownloadEnabled = isSmartDownloadEnabled,
@@ -113,7 +114,6 @@ fun SeriesScreen(
                     }
                 }
             },
-            onLoadSeasonEpisodes = viewModel::loadSeasonEpisodes,
             onObserveSeasonDownloadState = viewModel::observeSeasonDownloadState,
             onBack = viewModel::onGoHome,
             onMarkAsWatched = viewModel::markAsWatched,
@@ -129,11 +129,11 @@ fun SeriesScreen(
 @Composable
 private fun SeriesScreenInternal(
     series: Series,
+    selectSeason: (UUID, UUID) -> Unit,
     seriesDownloadState: DownloadState,
     seasonDownloadState: DownloadState,
     isSmartDownloadEnabled: Boolean,
     onDownloadOptionSelected: (SeriesDownloadOption, Season) -> Unit,
-    onLoadSeasonEpisodes: (UUID, UUID) -> Unit,
     onObserveSeasonDownloadState: (List<Episode>) -> Unit,
     onBack: () -> Unit,
     onMarkAsWatched: (Boolean) -> Unit = {},
@@ -175,7 +175,7 @@ private fun SeriesScreenInternal(
     }
 
     LaunchedEffect(series.id, selectedSeason?.id) {
-        selectedSeason?.let { onLoadSeasonEpisodes(series.id, it.id) }
+        selectedSeason?.let { selectSeason(series.id, it.id) }
     }
 
     LaunchedEffect(selectedSeason?.id, selectedSeason?.episodes) {

core/src/main/java/hu/bbara/purefin/core/feature/content/series/SeriesViewModel.kt

@@ -5,9 +5,9 @@ import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import hu.bbara.purefin.core.Offline
 import hu.bbara.purefin.core.data.LocalMediaRepository
+import hu.bbara.purefin.core.data.MediaMetadataUpdater
 import hu.bbara.purefin.core.download.DownloadState
 import hu.bbara.purefin.core.download.MediaDownloadController
-import hu.bbara.purefin.core.data.MediaMetadataUpdater
 import hu.bbara.purefin.core.navigation.EpisodeDto
 import hu.bbara.purefin.core.navigation.NavigationManager
 import hu.bbara.purefin.core.navigation.Route
@@ -98,12 +98,6 @@ class SeriesViewModel @Inject constructor(
         }
     }
 
-    fun loadSeasonEpisodes(seriesId: UUID, seasonId: UUID) {
-        viewModelScope.launch {
-            selectedMediaCatalogReader().loadSeasonEpisodes(seriesId, seasonId)
-        }
-    }
-
     fun downloadSeason(seriesId: UUID, seasonId: UUID) {
         viewModelScope.launch {
             val mediaCatalogReader = selectedMediaCatalogReader()
@@ -196,8 +190,14 @@ class SeriesViewModel @Inject constructor(
         _series.value = series
         viewModelScope.launch {
             val mediaCatalogReader = mediaCatalogReader(series.offline)
-            mediaCatalogReader.loadSeries(series.id)
-            mediaCatalogReader.loadSeasons(series.id)
+            launch { mediaCatalogReader.loadSeries(series.id) }
+            launch { mediaCatalogReader.loadSeasons(series.id) }
+        }
+    }
+
+    fun selectSeason(seriesId: UUID, seasonId: UUID) {
+        viewModelScope.launch {
+            selectedMediaCatalogReader().loadSeasonEpisodes(seriesId, seasonId)
         }
     }
 

data/src/main/java/hu/bbara/purefin/data/catalog/InMemoryLocalMediaRepository.kt

@@ -139,26 +139,46 @@ class InMemoryLocalMediaRepository @Inject constructor(
     private suspend fun loadSeasonsInternal(seriesId: UUID) {
         seriesState.value[seriesId]?.takeIf { it.seasons.isNotEmpty() }?.let { return }
 
-        val series = seriesState.value[seriesId] ?: throw RuntimeException("Series not found")
+        val seasons = jellyfinApiClient.getSeasons(seriesId).map { it.toSeason() }
 
-        val updatedSeries = series.copy(
-            seasons = jellyfinApiClient.getSeasons(seriesId).map { it.toSeason() }
-        )
-        seriesState.update { it + (updatedSeries.id to updatedSeries) }
+        // Await the parallel loadSeries to populate the series entry.
+        // Precondition: seriesId refers to a real series (selectSeries always uses a
+        // SeriesDto from a real series list). If loadSeries returns without populating
+        // state (null item / wrong type) this suspends until cancelled by structured
+        // concurrency when a sibling load* call fails.
+        seriesState.first { it.containsKey(seriesId) }
+
+        seriesState.update { current ->
+            val existing = current[seriesId] ?: return@update current
+            if (existing.seasons.isNotEmpty()) return@update current
+            current + (seriesId to existing.copy(seasons = seasons))
+        }
     }
 
     override suspend fun loadSeasonEpisodes(seriesId: UUID, seasonId: UUID) {
-        loadSeasons(seriesId)
+        // Fast path: season already cached with episodes or known empty — skip the fetch.
+        seriesState.value[seriesId]?.seasons?.firstOrNull { it.id == seasonId }?.let { cached ->
+            if (cached.episodes.isNotEmpty() || cached.episodeCount == 0) return
+        }
 
-        val series = seriesState.value[seriesId] ?: throw RuntimeException("Series not found")
+        // Fetch first so this runs concurrently with loadSeries/loadSeasons when launched
+        // from selectSeries. Precondition: seasons are pre-loaded by selectSeries and
+        // seasonId is always a valid season from a real EpisodeDto in this path.
+        val serverUrl = userSessionRepository.serverUrl.first()
+        val episodes = jellyfinApiClient.getEpisodesInSeason(seriesId, seasonId)
+            .map { it.toEpisode(serverUrl) }
+
+        // Await the season to be present in state (immediate when pre-loaded; waits for
+        // the parallel loadSeasons otherwise).
+        seriesState.first { it[seriesId]?.seasons?.any { it.id == seasonId } == true }
+
+        // Re-check guard after await: a concurrent call may have filled episodes already.
+        val series = seriesState.value[seriesId] ?: return
         val season = series.seasons.firstOrNull { it.id == seasonId } ?: return
         if (season.episodes.isNotEmpty() || season.episodeCount == 0) {
             return
         }
 
-        val serverUrl = userSessionRepository.serverUrl.first()
-        val episodes = jellyfinApiClient.getEpisodesInSeason(seriesId, seasonId)
-            .map { it.toEpisode(serverUrl) }
         seriesState.update { current ->
             val currentSeries = current[seriesId] ?: return@update current
             val updatedSeries = currentSeries.copy(