Check if has stats on details screen

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/DetailsActivity.kt

@@ -153,7 +153,7 @@ class DetailsActivity :
 		viewModel.isChaptersEmpty.observe(this, chaptersMenuInvalidator)
 		val menuInvalidator = MenuInvalidator(this)
 		viewModel.favouriteCategories.observe(this, menuInvalidator)
-		viewModel.isStatsEnabled.observe(this, menuInvalidator)
+		viewModel.isStatsAvailable.observe(this, menuInvalidator)
 		viewModel.remoteManga.observe(this, menuInvalidator)
 		viewModel.branches.observe(this) {
 			viewBinding.buttonDropdown.isVisible = it.size > 1

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/DetailsMenuProvider.kt

@@ -44,7 +44,7 @@ class DetailsMenuProvider(
 		menu.findItem(R.id.action_shortcut).isVisible = ShortcutManagerCompat.isRequestPinShortcutSupported(activity)
 		menu.findItem(R.id.action_scrobbling).isVisible = viewModel.isScrobblingAvailable
 		menu.findItem(R.id.action_online).isVisible = viewModel.remoteManga.value != null
-		menu.findItem(R.id.action_stats).isVisible = viewModel.isStatsEnabled.value
+		menu.findItem(R.id.action_stats).isVisible = viewModel.isStatsAvailable.value
 		menu.findItem(R.id.action_favourite).setIcon(
 			if (viewModel.favouriteCategories.value) R.drawable.ic_heart else R.drawable.ic_heart_outline,
 		)

app/src/main/kotlin/org/koitharu/kotatsu/details/ui/DetailsViewModel.kt

@@ -61,6 +61,7 @@ import org.koitharu.kotatsu.parsers.util.runCatchingCancellable
 import org.koitharu.kotatsu.scrobbling.common.domain.Scrobbler
 import org.koitharu.kotatsu.scrobbling.common.domain.model.ScrobblingInfo
 import org.koitharu.kotatsu.scrobbling.common.domain.model.ScrobblingStatus
+import org.koitharu.kotatsu.stats.data.StatsRepository
 import javax.inject.Inject
 
 @HiltViewModel
@@ -79,6 +80,7 @@ class DetailsViewModel @Inject constructor(
 	private val detailsLoadUseCase: DetailsLoadUseCase,
 	private val progressUpdateUseCase: ProgressUpdateUseCase,
 	private val readingTimeUseCase: ReadingTimeUseCase,
+	private val statsRepository: StatsRepository,
 ) : BaseViewModel() {
 
 	private val intent = MangaIntent(savedStateHandle)
@@ -100,9 +102,8 @@ class DetailsViewModel @Inject constructor(
 	val favouriteCategories = interactor.observeIsFavourite(mangaId)
 		.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, false)
 
-	val isStatsEnabled = settings.observeAsStateFlow(viewModelScope + Dispatchers.Default, AppSettings.KEY_STATS_ENABLED) {
-		isStatsEnabled
-	}
+	val isStatsAvailable = statsRepository.observeHasStats(mangaId)
+		.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, false)
 
 	val remoteManga = MutableStateFlow<Manga?>(null)
 

app/src/main/kotlin/org/koitharu/kotatsu/stats/data/StatsDao.kt

@@ -41,6 +41,9 @@ abstract class StatsDao {
 	@Query("DELETE FROM stats")
 	abstract suspend fun clear()
 
+	@Query("SELECT COUNT(*) FROM stats WHERE manga_id = :mangaId")
+	abstract fun observeRowCount(mangaId: Long): Flow<Int>
+
 	@Upsert
 	abstract suspend fun upsert(entity: StatsEntity)
 

app/src/main/kotlin/org/koitharu/kotatsu/stats/data/StatsRepository.kt

@@ -3,8 +3,17 @@ package org.koitharu.kotatsu.stats.data
 import androidx.collection.LongIntMap
 import androidx.collection.MutableLongIntMap
 import androidx.room.withTransaction
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.flow.map
 import org.koitharu.kotatsu.core.db.MangaDatabase
 import org.koitharu.kotatsu.core.db.entity.toManga
+import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.core.prefs.observeAsFlow
+import org.koitharu.kotatsu.core.util.ext.combine
 import org.koitharu.kotatsu.stats.domain.StatsPeriod
 import org.koitharu.kotatsu.stats.domain.StatsRecord
 import java.util.NavigableMap
@@ -13,6 +22,7 @@ import java.util.concurrent.TimeUnit
 import javax.inject.Inject
 
 class StatsRepository @Inject constructor(
+	private val settings: AppSettings,
 	private val db: MangaDatabase,
 ) {
 
@@ -71,4 +81,14 @@ class StatsRepository @Inject constructor(
 	suspend fun clearStats() {
 		db.getStatsDao().clear()
 	}
+
+	fun observeHasStats(mangaId: Long): Flow<Boolean> = settings.observeAsFlow(AppSettings.KEY_STATS_ENABLED) {
+		isStatsEnabled
+	}.flatMapLatest { isEnabled ->
+		if (isEnabled) {
+			db.getStatsDao().observeRowCount(mangaId).map { it > 0 }
+		} else {
+			flowOf(false)
+		}
+	}.distinctUntilChanged()
 }