Respect network data saver #1390

app/src/main/kotlin/org/koitharu/kotatsu/core/os/NetworkState.kt

@@ -2,6 +2,7 @@ package org.koitharu.kotatsu.core.os
 
 import android.net.ConnectivityManager
 import android.net.ConnectivityManager.NetworkCallback
+import android.net.ConnectivityManager.RESTRICT_BACKGROUND_STATUS_ENABLED
 import android.net.Network
 import android.net.NetworkCapabilities
 import android.net.NetworkRequest
@@ -42,6 +43,17 @@ class NetworkState(
 		connectivityManager.unregisterNetworkCallback(callback)
 	}
 
+	fun isMetered(): Boolean {
+		return connectivityManager.isActiveNetworkMetered
+	}
+
+	fun isDataSaverEnabled(): Boolean = Build.VERSION.SDK_INT >= Build.VERSION_CODES.N
+		&& connectivityManager.restrictBackgroundStatus == RESTRICT_BACKGROUND_STATUS_ENABLED
+
+	fun isRestricted() = isMetered() && isDataSaverEnabled()
+
+	fun isOfflineOrRestricted() = !isOnline() || isRestricted()
+
 	suspend fun awaitForConnection() {
 		if (value) {
 			return

app/src/main/kotlin/org/koitharu/kotatsu/core/parser/MangaDataRepository.kt

@@ -15,6 +15,7 @@ import org.koitharu.kotatsu.core.db.entity.MangaPrefsEntity
 import org.koitharu.kotatsu.core.db.entity.toEntities
 import org.koitharu.kotatsu.core.db.entity.toEntity
 import org.koitharu.kotatsu.core.db.entity.toManga
+import org.koitharu.kotatsu.core.db.entity.toMangaChapters
 import org.koitharu.kotatsu.core.db.entity.toMangaTags
 import org.koitharu.kotatsu.core.model.LocalMangaSource
 import org.koitharu.kotatsu.core.model.isLocal
@@ -119,10 +120,10 @@ class MangaDataRepository @Inject constructor(
 		return db.getMangaDao().findByPublicUrl(publicUrl)?.toManga()
 	}
 
-	suspend fun resolveIntent(intent: MangaIntent): Manga? = when {
-		intent.manga != null -> intent.manga
-		intent.mangaId != 0L -> findMangaById(intent.mangaId, true)
-		intent.uri != null -> resolverProvider.get().resolve(intent.uri)
+	suspend fun resolveIntent(intent: MangaIntent, withChapters: Boolean): Manga? = when {
+		intent.manga != null -> intent.manga.withCachedChaptersIfNeeded(withChapters)
+		intent.mangaId != 0L -> findMangaById(intent.mangaId, withChapters)
+		intent.uri != null -> resolverProvider.get().resolve(intent.uri).withCachedChaptersIfNeeded(withChapters)
 		else -> null
 	}
 
@@ -184,6 +185,17 @@ class MangaDataRepository @Inject constructor(
 		emitInitialState = emitInitialState,
 	)
 
+	private suspend fun Manga.withCachedChaptersIfNeeded(flag: Boolean): Manga = if (flag && chapters.isNullOrEmpty()) {
+		val cachedChapters = db.getChaptersDao().findAll(id)
+		if (cachedChapters.isEmpty()) {
+			this
+		} else {
+			copy(chapters = cachedChapters.toMangaChapters())
+		}
+	} else {
+		this
+	}
+
 	private fun MangaPrefsEntity.getColorFilterOrNull(): ReaderColorFilter? {
 		return if (cfBrightness != 0f || cfContrast != 0f || cfInvert || cfGrayscale) {
 			ReaderColorFilter(cfBrightness, cfContrast, cfInvert, cfGrayscale)

app/src/main/kotlin/org/koitharu/kotatsu/details/domain/DetailsLoadUseCase.kt

@@ -16,6 +16,7 @@ import kotlinx.coroutines.runInterruptible
 import okio.IOException
 import org.koitharu.kotatsu.core.model.isLocal
 import org.koitharu.kotatsu.core.nav.MangaIntent
+import org.koitharu.kotatsu.core.os.NetworkState
 import org.koitharu.kotatsu.core.parser.CachingMangaRepository
 import org.koitharu.kotatsu.core.parser.MangaDataRepository
 import org.koitharu.kotatsu.core.parser.MangaRepository
@@ -40,17 +41,12 @@ class DetailsLoadUseCase @Inject constructor(
 	private val recoverUseCase: RecoverMangaUseCase,
 	private val imageGetter: Html.ImageGetter,
 	private val newChaptersUseCaseProvider: Provider<CheckNewChaptersUseCase>,
+	private val networkState: NetworkState,
 ) {
 
 	operator fun invoke(intent: MangaIntent, force: Boolean): Flow<MangaDetails> = channelFlow {
-		val manga = requireNotNull(mangaDataRepository.resolveIntent(intent)) {
+		val manga = requireNotNull(mangaDataRepository.resolveIntent(intent, withChapters = true)) {
 			"Cannot resolve intent $intent"
-		}.let { m ->
-			if (m.chapters.isNullOrEmpty()) {
-				getCachedDetails(m.id) ?: m
-			} else {
-				m
-			}
 		}
 		val override = mangaDataRepository.getOverride(manga.id)
 		send(
@@ -69,6 +65,22 @@ class DetailsLoadUseCase @Inject constructor(
 		} else {
 			null
 		}
+		if (!force && networkState.isOfflineOrRestricted()) {
+			// try to avoid loading if has saved manga
+			val localManga = local?.await()
+			if (manga.isLocal || localManga != null) {
+				send(
+					MangaDetails(
+						manga = manga,
+						localManga = localManga,
+						override = override,
+						description = manga.description?.parseAsHtml(withImages = true)?.trim(),
+						isLoaded = true,
+					),
+				)
+				return@channelFlow
+			}
+		}
 		try {
 			val details = getDetails(manga, force)
 			launch { mangaDataRepository.updateChapters(details) }
@@ -147,8 +159,4 @@ class DetailsLoadUseCase @Inject constructor(
 	}.onFailure { e ->
 		e.printStackTraceDebug()
 	}
-
-	private suspend fun getCachedDetails(mangaId: Long): Manga? = runCatchingCancellable {
-		mangaDataRepository.findMangaById(mangaId, withChapters = true)
-	}.getOrNull()
 }