Refactor and optimization

app/src/debug/java/org/koitharu/kotatsu/utils/ext/DebugExt.kt

@@ -0,0 +1,3 @@
+package org.koitharu.kotatsu.utils.ext
+
+fun Throwable.printStackTraceDebug() = printStackTrace()

app/src/main/java/org/koitharu/kotatsu/base/domain/MangaUtils.kt

@@ -3,21 +3,21 @@ package org.koitharu.kotatsu.base.domain
 import android.graphics.BitmapFactory
 import android.net.Uri
 import android.util.Size
+import java.io.File
+import java.io.InputStream
+import java.util.zip.ZipFile
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.runInterruptible
 import okhttp3.OkHttpClient
 import okhttp3.Request
 import org.koin.core.component.KoinComponent
 import org.koin.core.component.get
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.core.network.CommonHeaders
 import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.parsers.model.MangaPage
 import org.koitharu.kotatsu.parsers.util.await
 import org.koitharu.kotatsu.parsers.util.medianOrNull
-import java.io.File
-import java.io.InputStream
-import java.util.zip.ZipFile
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 
 object MangaUtils : KoinComponent {
 
@@ -53,9 +53,7 @@ object MangaUtils : KoinComponent {
 			}
 			return size.width * 2 < size.height
 		} catch (e: Exception) {
-			if (BuildConfig.DEBUG) {
-				e.printStackTrace()
-			}
+			e.printStackTraceDebug()
 			return null
 		}
 	}
@@ -78,4 +76,4 @@ object MangaUtils : KoinComponent {
 		check(imageHeight > 0 && imageWidth > 0)
 		return Size(imageWidth, imageHeight)
 	}
-}
+}

app/src/main/java/org/koitharu/kotatsu/base/ui/BaseFullscreenActivity.kt

@@ -7,10 +7,12 @@ import android.view.View
 import android.view.WindowManager
 import androidx.viewbinding.ViewBinding
 
+@Suppress("DEPRECATION")
 private const val SYSTEM_UI_FLAGS_SHOWN = View.SYSTEM_UI_FLAG_LAYOUT_STABLE or
 	View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION or
 	View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
 
+@Suppress("DEPRECATION")
 private const val SYSTEM_UI_FLAGS_HIDDEN = View.SYSTEM_UI_FLAG_LAYOUT_STABLE or
 	View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION or
 	View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN or
@@ -18,7 +20,8 @@ private const val SYSTEM_UI_FLAGS_HIDDEN = View.SYSTEM_UI_FLAG_LAYOUT_STABLE or
 	View.SYSTEM_UI_FLAG_FULLSCREEN or
 	View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
 
-abstract class BaseFullscreenActivity<B : ViewBinding> : BaseActivity<B>(),
+abstract class BaseFullscreenActivity<B : ViewBinding> :
+	BaseActivity<B>(),
 	View.OnSystemUiVisibilityChangeListener {
 
 	override fun onCreate(savedInstanceState: Bundle?) {
@@ -35,16 +38,19 @@ abstract class BaseFullscreenActivity<B : ViewBinding> : BaseActivity<B>(),
 		showSystemUI()
 	}
 
+	@Suppress("DEPRECATION", "DeprecatedCallableAddReplaceWith")
 	@Deprecated("Deprecated in Java")
 	final override fun onSystemUiVisibilityChange(visibility: Int) {
 		onSystemUiVisibilityChanged(visibility and View.SYSTEM_UI_FLAG_FULLSCREEN == 0)
 	}
 
 	// TODO WindowInsetsControllerCompat works incorrect
+	@Suppress("DEPRECATION")
 	protected fun hideSystemUI() {
 		window.decorView.systemUiVisibility = SYSTEM_UI_FLAGS_HIDDEN
 	}
 
+	@Suppress("DEPRECATION")
 	protected fun showSystemUI() {
 		window.decorView.systemUiVisibility = SYSTEM_UI_FLAGS_SHOWN
 	}

app/src/main/java/org/koitharu/kotatsu/base/ui/BaseViewModel.kt

@@ -5,9 +5,9 @@ import androidx.lifecycle.viewModelScope
 import kotlin.coroutines.CoroutineContext
 import kotlin.coroutines.EmptyCoroutineContext
 import kotlinx.coroutines.*
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.base.ui.util.CountedBooleanLiveData
 import org.koitharu.kotatsu.utils.SingleLiveEvent
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 
 abstract class BaseViewModel : ViewModel() {
 
@@ -34,9 +34,7 @@ abstract class BaseViewModel : ViewModel() {
 	}
 
 	private fun createErrorHandler() = CoroutineExceptionHandler { _, throwable ->
-		if (BuildConfig.DEBUG) {
-			throwable.printStackTrace()
-		}
+		throwable.printStackTraceDebug()
 		if (throwable !is CancellationException) {
 			onError.postCall(throwable)
 		}

app/src/main/java/org/koitharu/kotatsu/core/github/GithubModule.kt

@@ -4,7 +4,5 @@ import org.koin.dsl.module
 
 val githubModule
 	get() = module {
-		factory {
-			GithubRepository(get())
-		}
+		factory { GithubRepository(get()) }
 	}

app/src/main/java/org/koitharu/kotatsu/core/github/VersionId.kt

@@ -54,27 +54,23 @@ class VersionId(
 		return result
 	}
 
-	companion object {
-
-		private fun variantWeight(variantType: String) =
-			when (variantType.lowercase(Locale.ROOT)) {
-				"a", "alpha" -> 1
-				"b", "beta" -> 2
-				"rc" -> 4
-				"" -> 8
-				else -> 0
-			}
-
-		fun parse(versionName: String): VersionId {
-			val parts = versionName.substringBeforeLast('-').split('.')
-			val variant = versionName.substringAfterLast('-', "")
-			return VersionId(
-				major = parts.getOrNull(0)?.toIntOrNull() ?: 0,
-				minor = parts.getOrNull(1)?.toIntOrNull() ?: 0,
-				build = parts.getOrNull(2)?.toIntOrNull() ?: 0,
-				variantType = variant.filter(Char::isLetter),
-				variantNumber = variant.filter(Char::isDigit).toIntOrNull() ?: 0
-			)
-		}
+	private fun variantWeight(variantType: String) = when (variantType.lowercase(Locale.ROOT)) {
+		"a", "alpha" -> 1
+		"b", "beta" -> 2
+		"rc" -> 4
+		"" -> 8
+		else -> 0
 	}
+}
+
+fun VersionId(versionName: String): VersionId {
+	val parts = versionName.substringBeforeLast('-').split('.')
+	val variant = versionName.substringAfterLast('-', "")
+	return VersionId(
+		major = parts.getOrNull(0)?.toIntOrNull() ?: 0,
+		minor = parts.getOrNull(1)?.toIntOrNull() ?: 0,
+		build = parts.getOrNull(2)?.toIntOrNull() ?: 0,
+		variantType = variant.filter(Char::isLetter),
+		variantNumber = variant.filter(Char::isDigit).toIntOrNull() ?: 0,
+	)
 }

app/src/main/java/org/koitharu/kotatsu/core/prefs/AppSettings.kt

@@ -1,6 +1,5 @@
 package org.koitharu.kotatsu.core.prefs
 
-import android.annotation.TargetApi
 import android.content.Context
 import android.content.SharedPreferences
 import android.net.ConnectivityManager

app/src/main/java/org/koitharu/kotatsu/core/prefs/AppSettingsObserver.kt

@@ -0,0 +1,35 @@
+package org.koitharu.kotatsu.core.prefs
+
+import androidx.lifecycle.liveData
+import kotlin.coroutines.CoroutineContext
+import kotlinx.coroutines.flow.flow
+
+fun <T> AppSettings.observeAsFlow(key: String, valueProducer: AppSettings.() -> T) = flow {
+	var lastValue: T = valueProducer()
+	emit(lastValue)
+	observe().collect {
+		if (it == key) {
+			val value = valueProducer()
+			if (value != lastValue) {
+				emit(value)
+			}
+			lastValue = value
+		}
+	}
+}
+
+fun <T> AppSettings.observeAsLiveData(
+	context: CoroutineContext,
+	key: String,
+	valueProducer: AppSettings.() -> T
+) = liveData(context) {
+	emit(valueProducer())
+	observe().collect {
+		if (it == key) {
+			val value = valueProducer()
+			if (value != latestValue) {
+				emit(value)
+			}
+		}
+	}
+}

app/src/main/java/org/koitharu/kotatsu/core/prefs/ReaderMode.kt

@@ -10,4 +10,4 @@ enum class ReaderMode(val id: Int) {
 
 		fun valueOf(id: Int) = values().firstOrNull { it.id == id }
 	}
-}
+}

app/src/main/java/org/koitharu/kotatsu/core/ui/AppCrashHandler.kt

@@ -4,6 +4,7 @@ import android.content.Context
 import android.content.Intent
 import android.util.Log
 import kotlin.system.exitProcess
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 
 class AppCrashHandler(private val applicationContext: Context) : Thread.UncaughtExceptionHandler {
 
@@ -13,7 +14,7 @@ class AppCrashHandler(private val applicationContext: Context) : Thread.Uncaught
 		try {
 			applicationContext.startActivity(intent)
 		} catch (t: Throwable) {
-			t.printStackTrace()
+			t.printStackTraceDebug()
 		}
 		Log.e("CRASH", e.message, e)
 		exitProcess(1)

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

@@ -191,7 +191,7 @@ class DetailsActivity :
 		R.id.action_save -> {
 			viewModel.manga.value?.let {
 				val chaptersCount = it.chapters?.size ?: 0
-				val branches = viewModel.branches.value.orEmpty()
+				val branches = viewModel.branches.value?.toList().orEmpty()
 				if (chaptersCount > 5 || branches.size > 1) {
 					showSaveConfirmation(it, chaptersCount, branches)
 				} else {

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

@@ -1,131 +1,106 @@
 package org.koitharu.kotatsu.details.ui
 
-import androidx.core.os.LocaleListCompat
 import androidx.lifecycle.asFlow
 import androidx.lifecycle.asLiveData
+import androidx.lifecycle.liveData
 import androidx.lifecycle.viewModelScope
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.Job
+import java.io.IOException
+import java.util.*
+import kotlinx.coroutines.*
 import kotlinx.coroutines.flow.*
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.plus
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.domain.MangaDataRepository
 import org.koitharu.kotatsu.base.domain.MangaIntent
 import org.koitharu.kotatsu.base.ui.BaseViewModel
 import org.koitharu.kotatsu.bookmarks.domain.Bookmark
 import org.koitharu.kotatsu.bookmarks.domain.BookmarksRepository
-import org.koitharu.kotatsu.core.exceptions.MangaNotFoundException
-import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.core.prefs.observeAsFlow
 import org.koitharu.kotatsu.details.ui.model.ChapterListItem
-import org.koitharu.kotatsu.details.ui.model.toListItem
 import org.koitharu.kotatsu.favourites.domain.FavouritesRepository
 import org.koitharu.kotatsu.history.domain.HistoryRepository
 import org.koitharu.kotatsu.local.domain.LocalMangaRepository
 import org.koitharu.kotatsu.parsers.model.Manga
-import org.koitharu.kotatsu.parsers.model.MangaChapter
 import org.koitharu.kotatsu.parsers.model.MangaSource
-import org.koitharu.kotatsu.parsers.util.mapToSet
-import org.koitharu.kotatsu.parsers.util.toTitleCase
 import org.koitharu.kotatsu.tracker.domain.TrackingRepository
 import org.koitharu.kotatsu.utils.SingleLiveEvent
 import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
-import org.koitharu.kotatsu.utils.ext.iterator
-import java.io.IOException
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 
 class DetailsViewModel(
-	private val intent: MangaIntent,
+	intent: MangaIntent,
 	private val historyRepository: HistoryRepository,
-	private val favouritesRepository: FavouritesRepository,
+	favouritesRepository: FavouritesRepository,
 	private val localMangaRepository: LocalMangaRepository,
 	private val trackingRepository: TrackingRepository,
-	private val mangaDataRepository: MangaDataRepository,
+	mangaDataRepository: MangaDataRepository,
 	private val bookmarksRepository: BookmarksRepository,
 	private val settings: AppSettings,
 ) : BaseViewModel() {
 
+	private val delegate = MangaDetailsDelegate(
+		intent = intent,
+		settings = settings,
+		mangaDataRepository = mangaDataRepository,
+		historyRepository = historyRepository,
+		localMangaRepository = localMangaRepository,
+	)
+
 	private var loadingJob: Job
-	private val mangaData = MutableStateFlow(intent.manga)
-	private val selectedBranch = MutableStateFlow<String?>(null)
 
 	val onShowToast = SingleLiveEvent<Int>()
 
-	private val history = mangaData.mapNotNull { it?.id }
-		.distinctUntilChanged()
-		.flatMapLatest { mangaId ->
-			historyRepository.observeOne(mangaId)
-		}.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, null)
+	private val history = historyRepository.observeOne(delegate.mangaId)
+		.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, null)
 
-	private val favourite = mangaData.mapNotNull { it?.id }
-		.distinctUntilChanged()
-		.flatMapLatest { mangaId ->
-			favouritesRepository.observeCategoriesIds(mangaId).map { it.isNotEmpty() }
-		}.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, false)
-
-	private val newChapters = mangaData.mapNotNull { it?.id }
-		.distinctUntilChanged()
-		.mapLatest { mangaId ->
-			trackingRepository.getNewChaptersCount(mangaId)
-		}.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, 0)
-
-	// Remote manga for saved and saved for remote
-	private val relatedManga = MutableStateFlow<Manga?>(null)
-	private val chaptersQuery = MutableStateFlow("")
-
-	private val chaptersReversed = settings.observe()
-		.filter { it == AppSettings.KEY_REVERSE_CHAPTERS }
-		.map { settings.chaptersReverse }
-		.onStart { emit(settings.chaptersReverse) }
+	private val favourite = favouritesRepository.observeCategoriesIds(delegate.mangaId).map { it.isNotEmpty() }
 		.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, false)
 
-	val manga = mangaData.filterNotNull()
-		.asLiveData(viewModelScope.coroutineContext)
-	val favouriteCategories = favourite
-		.asLiveData(viewModelScope.coroutineContext)
-	val newChaptersCount = newChapters
-		.asLiveData(viewModelScope.coroutineContext)
-	val readingHistory = history
-		.asLiveData(viewModelScope.coroutineContext)
-	val isChaptersReversed = chaptersReversed
-		.asLiveData(viewModelScope.coroutineContext)
+	private val newChapters = viewModelScope.async(Dispatchers.Default) {
+		trackingRepository.getNewChaptersCount(delegate.mangaId)
+	}
 
-	val bookmarks = mangaData.flatMapLatest {
+	private val chaptersQuery = MutableStateFlow("")
+
+	private val chaptersReversed = settings.observeAsFlow(AppSettings.KEY_REVERSE_CHAPTERS) { chaptersReverse }
+		.stateIn(viewModelScope + Dispatchers.Default, SharingStarted.Eagerly, false)
+
+	val manga = delegate.manga.filterNotNull().asLiveData(viewModelScope.coroutineContext)
+	val favouriteCategories = favourite.asLiveData(viewModelScope.coroutineContext)
+	val newChaptersCount = liveData(viewModelScope.coroutineContext) { emit(newChapters.await()) }
+	val readingHistory = history.asLiveData(viewModelScope.coroutineContext)
+	val isChaptersReversed = chaptersReversed.asLiveData(viewModelScope.coroutineContext)
+
+	val bookmarks = delegate.manga.flatMapLatest {
 		if (it != null) bookmarksRepository.observeBookmarks(it) else flowOf(emptyList())
 	}.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.Default)
 
 	val onMangaRemoved = SingleLiveEvent<Manga>()
 
-	val branches = mangaData.map {
-		it?.chapters?.mapToSet { x -> x.branch }?.sortedBy { x -> x }.orEmpty()
+	val branches = delegate.manga.map {
+		val chapters = it?.chapters ?: return@map emptySet()
+		chapters.mapTo(TreeSet()) { x -> x.branch }
 	}.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.Default)
 
 	val selectedBranchIndex = combine(
 		branches.asFlow(),
-		selectedBranch
+		delegate.selectedBranch
 	) { branches, selected ->
 		branches.indexOf(selected)
 	}.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.Default)
 
-	val isChaptersEmpty = mangaData.mapNotNull { m ->
-		m?.run { chapters.isNullOrEmpty() }
+	val isChaptersEmpty = delegate.manga.map { m ->
+		m?.chapters?.isEmpty() == true
 	}.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.Default, false)
 
 	val chapters = combine(
 		combine(
-			mangaData.map { it?.chapters.orEmpty() },
-			relatedManga,
-			history.map { it?.chapterId },
-			newChapters,
-			selectedBranch
-		) { chapters, related, currentId, newCount, branch ->
-			val relatedChapters = related?.chapters
-			if (related?.source != MangaSource.LOCAL && !relatedChapters.isNullOrEmpty()) {
-				mapChaptersWithSource(chapters, relatedChapters, currentId, newCount, branch)
-			} else {
-				mapChapters(chapters, relatedChapters, currentId, newCount, branch)
-			}
+			delegate.manga,
+			delegate.relatedManga,
+			history,
+			delegate.selectedBranch,
+		) { manga, related, history, branch ->
+			delegate.mapChapters(manga, related, history, newChapters.await(), branch)
 		},
 		chaptersReversed,
 		chaptersQuery,
@@ -134,7 +109,7 @@ class DetailsViewModel(
 	}.asLiveData(viewModelScope.coroutineContext + Dispatchers.Default)
 
 	val selectedBranchValue: String?
-		get() = selectedBranch.value
+		get() = delegate.selectedBranch.value
 
 	init {
 		loadingJob = doLoad()
@@ -146,7 +121,11 @@ class DetailsViewModel(
 	}
 
 	fun deleteLocal() {
-		val m = mangaData.value ?: return
+		val m = delegate.manga.value
+		if (m == null) {
+			onShowToast.call(R.string.file_not_found)
+			return
+		}
 		launchLoadingJob(Dispatchers.Default) {
 			val manga = if (m.source == MangaSource.LOCAL) m else localMangaRepository.findSavedManga(m)
 			checkNotNull(manga) { "Cannot find saved manga for ${m.title}" }
@@ -171,11 +150,11 @@ class DetailsViewModel(
 	}
 
 	fun setSelectedBranch(branch: String?) {
-		selectedBranch.value = branch
+		delegate.selectedBranch.value = branch
 	}
 
 	fun getRemoteManga(): Manga? {
-		return relatedManga.value?.takeUnless { it.source == MangaSource.LOCAL }
+		return delegate.relatedManga.value?.takeUnless { it.source == MangaSource.LOCAL }
 	}
 
 	fun performChapterSearch(query: String?) {
@@ -183,7 +162,7 @@ class DetailsViewModel(
 	}
 
 	fun onDownloadComplete(downloadedManga: Manga) {
-		val currentManga = mangaData.value ?: return
+		val currentManga = delegate.manga.value ?: return
 		if (currentManga.id != downloadedManga.id) {
 			return
 		}
@@ -194,142 +173,16 @@ class DetailsViewModel(
 				runCatching {
 					localMangaRepository.getDetails(downloadedManga)
 				}.onSuccess {
-					relatedManga.value = it
+					delegate.relatedManga.value = it
 				}.onFailure {
-					if (BuildConfig.DEBUG) {
-						it.printStackTrace()
-					}
+					it.printStackTraceDebug()
 				}
 			}
 		}
 	}
 
 	private fun doLoad() = launchLoadingJob(Dispatchers.Default) {
-		var manga = mangaDataRepository.resolveIntent(intent)
-			?: throw MangaNotFoundException("Cannot find manga")
-		mangaData.value = manga
-		manga = MangaRepository(manga.source).getDetails(manga)
-		// find default branch
-		val hist = historyRepository.getOne(manga)
-		selectedBranch.value = if (hist != null) {
-			val currentChapter = manga.chapters?.find { it.id == hist.chapterId }
-			if (currentChapter != null) currentChapter.branch else predictBranch(manga.chapters)
-		} else {
-			predictBranch(manga.chapters)
-		}
-		mangaData.value = manga
-		relatedManga.value = runCatching {
-			if (manga.source == MangaSource.LOCAL) {
-				val m = localMangaRepository.getRemoteManga(manga) ?: return@runCatching null
-				MangaRepository(m.source).getDetails(m)
-			} else {
-				localMangaRepository.findSavedManga(manga)
-			}
-		}.onFailure { error ->
-			if (BuildConfig.DEBUG) error.printStackTrace()
-		}.getOrNull()
-	}
-
-	private fun mapChapters(
-		chapters: List<MangaChapter>,
-		downloadedChapters: List<MangaChapter>?,
-		currentId: Long?,
-		newCount: Int,
-		branch: String?,
-	): List<ChapterListItem> {
-		val result = ArrayList<ChapterListItem>(chapters.size)
-		val dateFormat = settings.getDateFormat()
-		val currentIndex = chapters.indexOfFirst { it.id == currentId }
-		val firstNewIndex = chapters.size - newCount
-		val downloadedIds = downloadedChapters?.mapToSet { it.id }
-		for (i in chapters.indices) {
-			val chapter = chapters[i]
-			if (chapter.branch != branch) {
-				continue
-			}
-			result += chapter.toListItem(
-				isCurrent = i == currentIndex,
-				isUnread = i > currentIndex,
-				isNew = i >= firstNewIndex,
-				isMissing = false,
-				isDownloaded = downloadedIds?.contains(chapter.id) == true,
-				dateFormat = dateFormat,
-			)
-		}
-		return result
-	}
-
-	private fun mapChaptersWithSource(
-		chapters: List<MangaChapter>,
-		sourceChapters: List<MangaChapter>,
-		currentId: Long?,
-		newCount: Int,
-		branch: String?,
-	): List<ChapterListItem> {
-		val chaptersMap = chapters.associateByTo(HashMap(chapters.size)) { it.id }
-		val result = ArrayList<ChapterListItem>(sourceChapters.size)
-		val currentIndex = sourceChapters.indexOfFirst { it.id == currentId }
-		val firstNewIndex = sourceChapters.size - newCount
-		val dateFormat = settings.getDateFormat()
-		for (i in sourceChapters.indices) {
-			val chapter = sourceChapters[i]
-			val localChapter = chaptersMap.remove(chapter.id)
-			if (chapter.branch != branch) {
-				continue
-			}
-			result += localChapter?.toListItem(
-				isCurrent = i == currentIndex,
-				isUnread = i > currentIndex,
-				isNew = i >= firstNewIndex,
-				isMissing = false,
-				isDownloaded = false,
-				dateFormat = dateFormat,
-			) ?: chapter.toListItem(
-				isCurrent = i == currentIndex,
-				isUnread = i > currentIndex,
-				isNew = i >= firstNewIndex,
-				isMissing = true,
-				isDownloaded = false,
-				dateFormat = dateFormat,
-			)
-		}
-		if (chaptersMap.isNotEmpty()) { // some chapters on device but not online source
-			result.ensureCapacity(result.size + chaptersMap.size)
-			chaptersMap.values.mapNotNullTo(result) {
-				if (it.branch == branch) {
-					it.toListItem(
-						isCurrent = false,
-						isUnread = true,
-						isNew = false,
-						isMissing = false,
-						isDownloaded = false,
-						dateFormat = dateFormat,
-					)
-				} else {
-					null
-				}
-			}
-			result.sortBy { it.chapter.number }
-		}
-		return result
-	}
-
-	private fun predictBranch(chapters: List<MangaChapter>?): String? {
-		if (chapters.isNullOrEmpty()) {
-			return null
-		}
-		val groups = chapters.groupBy { it.branch }
-		for (locale in LocaleListCompat.getAdjustedDefault()) {
-			var language = locale.getDisplayLanguage(locale).toTitleCase(locale)
-			if (groups.containsKey(language)) {
-				return language
-			}
-			language = locale.getDisplayName(locale).toTitleCase(locale)
-			if (groups.containsKey(language)) {
-				return language
-			}
-		}
-		return groups.maxByOrNull { it.value.size }?.key
+		delegate.doLoad()
 	}
 
 	private fun List<ChapterListItem>.filterSearch(query: String): List<ChapterListItem> {

app/src/main/java/org/koitharu/kotatsu/details/ui/MangaDetailsDelegate.kt

@@ -0,0 +1,184 @@
+package org.koitharu.kotatsu.details.ui
+
+import androidx.core.os.LocaleListCompat
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import org.koitharu.kotatsu.base.domain.MangaDataRepository
+import org.koitharu.kotatsu.base.domain.MangaIntent
+import org.koitharu.kotatsu.core.exceptions.MangaNotFoundException
+import org.koitharu.kotatsu.core.model.MangaHistory
+import org.koitharu.kotatsu.core.parser.MangaRepository
+import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.details.ui.model.ChapterListItem
+import org.koitharu.kotatsu.details.ui.model.toListItem
+import org.koitharu.kotatsu.history.domain.HistoryRepository
+import org.koitharu.kotatsu.local.domain.LocalMangaRepository
+import org.koitharu.kotatsu.parsers.model.Manga
+import org.koitharu.kotatsu.parsers.model.MangaChapter
+import org.koitharu.kotatsu.parsers.model.MangaSource
+import org.koitharu.kotatsu.parsers.util.mapToSet
+import org.koitharu.kotatsu.parsers.util.toTitleCase
+import org.koitharu.kotatsu.utils.ext.iterator
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
+
+class MangaDetailsDelegate(
+	private val intent: MangaIntent,
+	private val settings: AppSettings,
+	private val mangaDataRepository: MangaDataRepository,
+	private val historyRepository: HistoryRepository,
+	private val localMangaRepository: LocalMangaRepository,
+) {
+
+	private val mangaData = MutableStateFlow(intent.manga)
+
+	val selectedBranch = MutableStateFlow<String?>(null)
+	// Remote manga for saved and saved for remote
+	val relatedManga = MutableStateFlow<Manga?>(null)
+	val manga: StateFlow<Manga?>
+		get() = mangaData
+	val mangaId = intent.manga?.id ?: intent.mangaId
+
+	suspend fun doLoad() {
+		var manga = mangaDataRepository.resolveIntent(intent)
+			?: throw MangaNotFoundException("Cannot find manga")
+		mangaData.value = manga
+		manga = MangaRepository(manga.source).getDetails(manga)
+		// find default branch
+		val hist = historyRepository.getOne(manga)
+		selectedBranch.value = if (hist != null) {
+			val currentChapter = manga.chapters?.find { it.id == hist.chapterId }
+			if (currentChapter != null) currentChapter.branch else predictBranch(manga.chapters)
+		} else {
+			predictBranch(manga.chapters)
+		}
+		mangaData.value = manga
+		relatedManga.value = runCatching {
+			if (manga.source == MangaSource.LOCAL) {
+				val m = localMangaRepository.getRemoteManga(manga) ?: return@runCatching null
+				MangaRepository(m.source).getDetails(m)
+			} else {
+				localMangaRepository.findSavedManga(manga)
+			}
+		}.onFailure { error ->
+			error.printStackTraceDebug()
+		}.getOrNull()
+	}
+
+	fun mapChapters(
+		manga: Manga?,
+		related: Manga?,
+		history: MangaHistory?,
+		newCount: Int,
+		branch: String?,
+	): List<ChapterListItem> {
+		val chapters = manga?.chapters ?: return emptyList()
+		val relatedChapters = related?.chapters
+		return if (related?.source != MangaSource.LOCAL && !relatedChapters.isNullOrEmpty()) {
+			mapChaptersWithSource(chapters, relatedChapters, history?.chapterId, newCount, branch)
+		} else {
+			mapChapters(chapters, relatedChapters, history?.chapterId, newCount, branch)
+		}
+	}
+
+	private fun mapChapters(
+		chapters: List<MangaChapter>,
+		downloadedChapters: List<MangaChapter>?,
+		currentId: Long?,
+		newCount: Int,
+		branch: String?,
+	): List<ChapterListItem> {
+		val result = ArrayList<ChapterListItem>(chapters.size)
+		val dateFormat = settings.getDateFormat()
+		val currentIndex = chapters.indexOfFirst { it.id == currentId }
+		val firstNewIndex = chapters.size - newCount
+		val downloadedIds = downloadedChapters?.mapToSet { it.id }
+		for (i in chapters.indices) {
+			val chapter = chapters[i]
+			if (chapter.branch != branch) {
+				continue
+			}
+			result += chapter.toListItem(
+				isCurrent = i == currentIndex,
+				isUnread = i > currentIndex,
+				isNew = i >= firstNewIndex,
+				isMissing = false,
+				isDownloaded = downloadedIds?.contains(chapter.id) == true,
+				dateFormat = dateFormat,
+			)
+		}
+		return result
+	}
+
+	private fun mapChaptersWithSource(
+		chapters: List<MangaChapter>,
+		sourceChapters: List<MangaChapter>,
+		currentId: Long?,
+		newCount: Int,
+		branch: String?,
+	): List<ChapterListItem> {
+		val chaptersMap = chapters.associateByTo(HashMap(chapters.size)) { it.id }
+		val result = ArrayList<ChapterListItem>(sourceChapters.size)
+		val currentIndex = sourceChapters.indexOfFirst { it.id == currentId }
+		val firstNewIndex = sourceChapters.size - newCount
+		val dateFormat = settings.getDateFormat()
+		for (i in sourceChapters.indices) {
+			val chapter = sourceChapters[i]
+			val localChapter = chaptersMap.remove(chapter.id)
+			if (chapter.branch != branch) {
+				continue
+			}
+			result += localChapter?.toListItem(
+				isCurrent = i == currentIndex,
+				isUnread = i > currentIndex,
+				isNew = i >= firstNewIndex,
+				isMissing = false,
+				isDownloaded = false,
+				dateFormat = dateFormat,
+			) ?: chapter.toListItem(
+				isCurrent = i == currentIndex,
+				isUnread = i > currentIndex,
+				isNew = i >= firstNewIndex,
+				isMissing = true,
+				isDownloaded = false,
+				dateFormat = dateFormat,
+			)
+		}
+		if (chaptersMap.isNotEmpty()) { // some chapters on device but not online source
+			result.ensureCapacity(result.size + chaptersMap.size)
+			chaptersMap.values.mapNotNullTo(result) {
+				if (it.branch == branch) {
+					it.toListItem(
+						isCurrent = false,
+						isUnread = true,
+						isNew = false,
+						isMissing = false,
+						isDownloaded = false,
+						dateFormat = dateFormat,
+					)
+				} else {
+					null
+				}
+			}
+			result.sortBy { it.chapter.number }
+		}
+		return result
+	}
+
+	private fun predictBranch(chapters: List<MangaChapter>?): String? {
+		if (chapters.isNullOrEmpty()) {
+			return null
+		}
+		val groups = chapters.groupBy { it.branch }
+		for (locale in LocaleListCompat.getAdjustedDefault()) {
+			var language = locale.getDisplayLanguage(locale).toTitleCase(locale)
+			if (groups.containsKey(language)) {
+				return language
+			}
+			language = locale.getDisplayName(locale).toTitleCase(locale)
+			if (groups.containsKey(language)) {
+				return language
+			}
+		}
+		return groups.maxByOrNull { it.value.size }?.key
+	}
+}

app/src/main/java/org/koitharu/kotatsu/download/domain/DownloadManager.kt

@@ -12,7 +12,6 @@ import kotlinx.coroutines.sync.Semaphore
 import okhttp3.OkHttpClient
 import okhttp3.Request
 import okio.IOException
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.network.CommonHeaders
 import org.koitharu.kotatsu.core.parser.MangaRepository
@@ -24,6 +23,7 @@ import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaSource
 import org.koitharu.kotatsu.parsers.util.await
 import org.koitharu.kotatsu.utils.ext.deleteAwait
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 import org.koitharu.kotatsu.utils.ext.referer
 import org.koitharu.kotatsu.utils.ext.waitForNetwork
 import org.koitharu.kotatsu.utils.progress.ProgressJob
@@ -156,9 +156,7 @@ class DownloadManager(
 			outState.value = DownloadState.Cancelled(startId, manga, cover)
 			throw e
 		} catch (e: Throwable) {
-			if (BuildConfig.DEBUG) {
-				e.printStackTrace()
-			}
+			e.printStackTraceDebug()
 			outState.value = DownloadState.Error(startId, manga, cover, e)
 		} finally {
 			withContext(NonCancellable) {

app/src/main/java/org/koitharu/kotatsu/download/ui/DownloadsActivity.kt

@@ -3,10 +3,8 @@ package org.koitharu.kotatsu.download.ui
 import android.content.Context
 import android.content.Intent
 import android.os.Bundle
-import android.view.ViewGroup
 import androidx.core.graphics.Insets
 import androidx.core.view.isVisible
-import androidx.core.view.updateLayoutParams
 import androidx.core.view.updatePadding
 import androidx.lifecycle.lifecycleScope
 import kotlinx.coroutines.flow.flatMapLatest
@@ -17,7 +15,7 @@ import org.koin.android.ext.android.get
 import org.koitharu.kotatsu.base.ui.BaseActivity
 import org.koitharu.kotatsu.databinding.ActivityDownloadsBinding
 import org.koitharu.kotatsu.download.ui.service.DownloadService
-import org.koitharu.kotatsu.utils.LifecycleAwareServiceConnection
+import org.koitharu.kotatsu.utils.bindServiceWithLifecycle
 
 class DownloadsActivity : BaseActivity<ActivityDownloadsBinding>() {
 
@@ -28,11 +26,10 @@ class DownloadsActivity : BaseActivity<ActivityDownloadsBinding>() {
 		val adapter = DownloadsAdapter(lifecycleScope, get())
 		binding.recyclerView.setHasFixedSize(true)
 		binding.recyclerView.adapter = adapter
-		LifecycleAwareServiceConnection.bindService(
-			this,
-			this,
-			Intent(this, DownloadService::class.java),
-			0
+		bindServiceWithLifecycle(
+			owner = this,
+			service = Intent(this, DownloadService::class.java),
+			flags = 0,
 		).service.flatMapLatest { binder ->
 			(binder as? DownloadService.DownloadBinder)?.downloads ?: flowOf(null)
 		}.onEach {

app/src/main/java/org/koitharu/kotatsu/favourites/ui/categories/FavouritesCategoriesViewModel.kt

@@ -3,10 +3,11 @@ package org.koitharu.kotatsu.favourites.ui.categories
 import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
-import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.flow.combine
 import org.koitharu.kotatsu.base.ui.BaseViewModel
 import org.koitharu.kotatsu.core.model.FavouriteCategory
 import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.core.prefs.observeAsFlow
 import org.koitharu.kotatsu.favourites.domain.FavouritesRepository
 import org.koitharu.kotatsu.favourites.ui.categories.adapter.CategoryListModel
 import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
@@ -70,9 +71,7 @@ class FavouritesCategoriesViewModel(
 		return result
 	}
 
-	private fun observeAllCategoriesVisible() = settings.observe()
-		.filter { it == AppSettings.KEY_ALL_FAVOURITES_VISIBLE }
-		.map { settings.isAllFavouritesVisible }
-		.onStart { emit(settings.isAllFavouritesVisible) }
-		.distinctUntilChanged()
+	private fun observeAllCategoriesVisible() = settings.observeAsFlow(AppSettings.KEY_ALL_FAVOURITES_VISIBLE) {
+		isAllFavouritesVisible
+	}
 }

app/src/main/java/org/koitharu/kotatsu/favourites/ui/categories/adapter/CategoryAD.kt

@@ -16,7 +16,7 @@ fun categoryAD(
 		clickListener.onItemClick(item.category, it)
 	}
 	@Suppress("ClickableViewAccessibility")
-	binding.imageViewHandle.setOnTouchListener { v, event ->
+	binding.imageViewHandle.setOnTouchListener { _, event ->
 		if (event.actionMasked == MotionEvent.ACTION_DOWN) {
 			clickListener.onItemLongClick(item.category, itemView)
 		} else {

app/src/main/java/org/koitharu/kotatsu/history/ui/HistoryListViewModel.kt

@@ -2,14 +2,15 @@ package org.koitharu.kotatsu.history.ui
 
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.viewModelScope
-import java.util.*
-import java.util.concurrent.TimeUnit
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.onEach
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.os.ShortcutsRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.prefs.ListMode
+import org.koitharu.kotatsu.core.prefs.observeAsFlow
 import org.koitharu.kotatsu.core.ui.DateTimeAgo
 import org.koitharu.kotatsu.history.domain.HistoryRepository
 import org.koitharu.kotatsu.history.domain.MangaWithHistory
@@ -19,6 +20,8 @@ import org.koitharu.kotatsu.tracker.domain.TrackingRepository
 import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
 import org.koitharu.kotatsu.utils.ext.daysDiff
 import org.koitharu.kotatsu.utils.ext.onFirst
+import java.util.*
+import java.util.concurrent.TimeUnit
 
 class HistoryListViewModel(
 	private val repository: HistoryRepository,
@@ -29,11 +32,7 @@ class HistoryListViewModel(
 
 	val isGroupingEnabled = MutableLiveData<Boolean>()
 
-	private val historyGrouping = settings.observe()
-		.filter { it == AppSettings.KEY_HISTORY_GROUPING }
-		.map { settings.historyGrouping }
-		.onStart { emit(settings.historyGrouping) }
-		.distinctUntilChanged()
+	private val historyGrouping = settings.observeAsFlow(AppSettings.KEY_HISTORY_GROUPING) { historyGrouping }
 		.onEach { isGroupingEnabled.postValue(it) }
 
 	override val content = combine(

app/src/main/java/org/koitharu/kotatsu/list/ui/MangaListViewModel.kt

@@ -4,16 +4,14 @@ import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.flow.onEach
 import org.koitharu.kotatsu.base.ui.BaseViewModel
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.prefs.ListMode
+import org.koitharu.kotatsu.core.prefs.observeAsFlow
+import org.koitharu.kotatsu.core.prefs.observeAsLiveData
 import org.koitharu.kotatsu.list.ui.model.ListModel
-import org.koitharu.kotatsu.list.ui.model.MangaGridModel
-import org.koitharu.kotatsu.list.ui.model.MangaListDetailedModel
-import org.koitharu.kotatsu.list.ui.model.MangaListModel
 import org.koitharu.kotatsu.parsers.model.MangaTag
-import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
 
 abstract class MangaListViewModel(
 	private val settings: AppSettings,
@@ -21,20 +19,15 @@ abstract class MangaListViewModel(
 
 	abstract val content: LiveData<List<ListModel>>
 	val listMode = MutableLiveData<ListMode>()
-	val gridScale = settings.observe()
-		.filter { it == AppSettings.KEY_GRID_SIZE }
-		.map { settings.gridSize / 100f }
-		.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.IO) {
-			settings.gridSize / 100f
-		}
+	val gridScale = settings.observeAsLiveData(
+		context = viewModelScope.coroutineContext + Dispatchers.Default,
+		key = AppSettings.KEY_GRID_SIZE,
+		valueProducer = { gridSize / 100f },
+	)
 
 	open fun onRemoveFilterTag(tag: MangaTag) = Unit
 
-	protected fun createListModeFlow() = settings.observe()
-		.filter { it == AppSettings.KEY_LIST_MODE }
-		.map { settings.listMode }
-		.onStart { emit(settings.listMode) }
-		.distinctUntilChanged()
+	protected fun createListModeFlow() = settings.observeAsFlow(AppSettings.KEY_LIST_MODE) { listMode }
 		.onEach {
 			if (listMode.value != it) {
 				listMode.postValue(it)

app/src/main/java/org/koitharu/kotatsu/list/ui/adapter/CurrentFilterAD.kt

@@ -13,7 +13,7 @@ fun currentFilterAD(
 
 	val chipGroup = itemView as ChipsView
 
-	chipGroup.onChipCloseClickListener = ChipsView.OnChipCloseClickListener { chip, data ->
+	chipGroup.onChipCloseClickListener = ChipsView.OnChipCloseClickListener { _, data ->
 		listener.onTagRemoveClick(data as? MangaTag ?: return@OnChipCloseClickListener)
 	}
 

app/src/main/java/org/koitharu/kotatsu/list/ui/filter/FilterCoordinator.kt

@@ -1,18 +1,18 @@
 package org.koitharu.kotatsu.list.ui.filter
 
 import androidx.annotation.WorkerThread
+import java.util.*
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.CoroutineStart
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.async
 import kotlinx.coroutines.flow.*
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.domain.MangaDataRepository
 import org.koitharu.kotatsu.core.parser.RemoteMangaRepository
 import org.koitharu.kotatsu.parsers.model.MangaTag
 import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
-import java.util.*
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 
 class FilterCoordinator(
 	private val repository: RemoteMangaRepository,
@@ -113,7 +113,7 @@ class FilterCoordinator(
 					FilterItem.Sort(it, isSelected = it == state.sortOrder)
 				}
 			}
-			if(allTags.isLoading || allTags.isError || tags.isNotEmpty()) {
+			if (allTags.isLoading || allTags.isError || tags.isNotEmpty()) {
 				list.add(FilterItem.Header(R.string.genres, state.tags.size))
 				tags.mapTo(list) {
 					FilterItem.Tag(it, isChecked = it in state.tags)
@@ -153,9 +153,7 @@ class FilterCoordinator(
 		runCatching {
 			repository.getTags()
 		}.onFailure { error ->
-			if (BuildConfig.DEBUG) {
-				error.printStackTrace()
-			}
+			error.printStackTraceDebug()
 		}.getOrNull()
 	}
 

app/src/main/java/org/koitharu/kotatsu/local/ui/LocalListFragment.kt

@@ -15,11 +15,11 @@ import androidx.core.net.toUri
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.snackbar.Snackbar
 import org.koin.androidx.viewmodel.ext.android.viewModel
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.download.ui.service.DownloadService
 import org.koitharu.kotatsu.list.ui.MangaListFragment
 import org.koitharu.kotatsu.utils.ShareHelper
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 import org.koitharu.kotatsu.utils.progress.Progress
 
 class LocalListFragment : MangaListFragment(), ActivityResultCallback<List<@JvmSuppressWildcards Uri>> {
@@ -68,9 +68,7 @@ class LocalListFragment : MangaListFragment(), ActivityResultCallback<List<@JvmS
 		try {
 			importCall.launch(arrayOf("*/*"))
 		} catch (e: ActivityNotFoundException) {
-			if (BuildConfig.DEBUG) {
-				e.printStackTrace()
-			}
+			e.printStackTraceDebug()
 			Snackbar.make(
 				binding.recyclerView,
 				R.string.operation_not_supported,

app/src/main/java/org/koitharu/kotatsu/local/ui/LocalListViewModel.kt

@@ -3,6 +3,7 @@ package org.koitharu.kotatsu.local.ui
 import android.net.Uri
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.viewModelScope
+import java.io.IOException
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -10,7 +11,6 @@ import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.os.ShortcutsRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
@@ -22,8 +22,8 @@ import org.koitharu.kotatsu.local.domain.LocalMangaRepository
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.utils.SingleLiveEvent
 import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 import org.koitharu.kotatsu.utils.progress.Progress
-import java.io.IOException
 
 class LocalListViewModel(
 	private val repository: LocalMangaRepository,
@@ -127,9 +127,7 @@ class LocalListViewModel(
 				runCatching {
 					repository.cleanup()
 				}.onFailure { error ->
-					if (BuildConfig.DEBUG) {
-						error.printStackTrace()
-					}
+					error.printStackTraceDebug()
 				}
 			}
 		}

app/src/main/java/org/koitharu/kotatsu/main/ui/MainViewModel.kt

@@ -8,6 +8,7 @@ import kotlinx.coroutines.flow.onStart
 import org.koitharu.kotatsu.base.ui.BaseViewModel
 import org.koitharu.kotatsu.core.exceptions.EmptyHistoryException
 import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.core.prefs.observeAsLiveData
 import org.koitharu.kotatsu.history.domain.HistoryRepository
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.utils.SingleLiveEvent
@@ -21,11 +22,11 @@ class MainViewModel(
 	val onOpenReader = SingleLiveEvent<Manga>()
 	var defaultSection by settings::defaultSection
 
-	val isSuggestionsEnabled = settings.observe()
-		.filter { it == AppSettings.KEY_SUGGESTIONS }
-		.onStart { emit("") }
-		.map { settings.isSuggestionsEnabled }
-		.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.Default)
+	val isSuggestionsEnabled = settings.observeAsLiveData(
+		context = viewModelScope.coroutineContext + Dispatchers.Default,
+		key = AppSettings.KEY_SUGGESTIONS,
+		valueProducer = { isSuggestionsEnabled }
+	)
 
 	val isResumeEnabled = historyRepository
 		.observeHasItems()

app/src/main/java/org/koitharu/kotatsu/reader/data/ModelMapping.kt

@@ -0,0 +1,27 @@
+package org.koitharu.kotatsu.reader.data
+
+import org.koitharu.kotatsu.parsers.model.Manga
+import org.koitharu.kotatsu.parsers.model.MangaChapter
+
+fun Manga.filterChapters(branch: String?): Manga {
+	if (chapters.isNullOrEmpty()) return this
+	return copy(chapters = chapters?.filter { it.branch == branch })
+}
+
+private fun Manga.copy(chapters: List<MangaChapter>?) = Manga(
+	id = id,
+	title = title,
+	altTitle = altTitle,
+	url = url,
+	publicUrl = publicUrl,
+	rating = rating,
+	isNsfw = isNsfw,
+	coverUrl = coverUrl,
+	tags = tags,
+	state = state,
+	author = author,
+	largeCoverUrl = largeCoverUrl,
+	description = description,
+	chapters = chapters,
+	source = source,
+)

app/src/main/java/org/koitharu/kotatsu/reader/ui/ReaderActivity.kt

@@ -6,11 +6,13 @@ import android.content.Intent
 import android.net.Uri
 import android.os.Bundle
 import android.view.*
-import android.widget.Toast
 import androidx.activity.result.ActivityResultCallback
 import androidx.core.graphics.Insets
-import androidx.core.view.*
-import androidx.fragment.app.commit
+import androidx.core.view.OnApplyWindowInsetsListener
+import androidx.core.view.WindowInsetsCompat
+import androidx.core.view.isVisible
+import androidx.core.view.updatePadding
+import androidx.lifecycle.flowWithLifecycle
 import androidx.lifecycle.lifecycleScope
 import androidx.transition.Slide
 import androidx.transition.TransitionManager
@@ -37,11 +39,7 @@ import org.koitharu.kotatsu.databinding.ActivityReaderBinding
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaChapter
 import org.koitharu.kotatsu.parsers.model.MangaPage
-import org.koitharu.kotatsu.reader.ui.pager.BaseReader
 import org.koitharu.kotatsu.reader.ui.pager.ReaderUiState
-import org.koitharu.kotatsu.reader.ui.pager.reversed.ReversedReaderFragment
-import org.koitharu.kotatsu.reader.ui.pager.standard.PagerReaderFragment
-import org.koitharu.kotatsu.reader.ui.pager.webtoon.WebtoonReaderFragment
 import org.koitharu.kotatsu.reader.ui.thumbnails.OnPageSelectListener
 import org.koitharu.kotatsu.reader.ui.thumbnails.PagesThumbnailsSheet
 import org.koitharu.kotatsu.settings.SettingsActivity
@@ -51,6 +49,8 @@ import org.koitharu.kotatsu.utils.ShareHelper
 import org.koitharu.kotatsu.utils.ext.getDisplayMessage
 import org.koitharu.kotatsu.utils.ext.hasGlobalPoint
 import org.koitharu.kotatsu.utils.ext.observeWithPrevious
+import org.koitharu.kotatsu.utils.ext.postDelayed
+import java.util.concurrent.TimeUnit
 
 class ReaderActivity :
 	BaseFullscreenActivity<ActivityReaderBinding>(),
@@ -75,13 +75,13 @@ class ReaderActivity :
 	private lateinit var controlDelegate: ReaderControlDelegate
 	private val savePageRequest = registerForActivityResult(PageSaveContract(), this)
 	private var gestureInsets: Insets = Insets.NONE
-
-	private val reader
-		get() = supportFragmentManager.findFragmentById(R.id.container) as? BaseReader<*>
+	private lateinit var readerManager: ReaderManager
+	private val hideUiRunnable = Runnable { setUiIsVisible(false) }
 
 	override fun onCreate(savedInstanceState: Bundle?) {
 		super.onCreate(savedInstanceState)
 		setContentView(ActivityReaderBinding.inflate(layoutInflater))
+		readerManager = ReaderManager(supportFragmentManager, R.id.container)
 		supportActionBar?.setDisplayHomeAsUpEnabled(true)
 		touchHelper = GridTouchHelper(this, this)
 		orientationHelper = ScreenOrientationHelper(this)
@@ -91,6 +91,7 @@ class ReaderActivity :
 		insetsDelegate.interceptingWindowInsetsListener = this
 
 		orientationHelper.observeAutoOrientation()
+			.flowWithLifecycle(lifecycle)
 			.onEach {
 				binding.toolbarBottom.menu.findItem(R.id.action_screen_rotate).isVisible = !it
 			}.launchIn(lifecycleScope)
@@ -113,33 +114,20 @@ class ReaderActivity :
 	}
 
 	private fun onInitReader(mode: ReaderMode) {
-		val currentReader = reader
-		when (mode) {
-			ReaderMode.WEBTOON -> if (currentReader !is WebtoonReaderFragment) {
-				supportFragmentManager.commit {
-					replace(R.id.container, WebtoonReaderFragment())
-				}
-			}
-			ReaderMode.REVERSED -> if (currentReader !is ReversedReaderFragment) {
-				supportFragmentManager.commit {
-					replace(R.id.container, ReversedReaderFragment())
-				}
-			}
-			ReaderMode.STANDARD -> if (currentReader !is PagerReaderFragment) {
-				supportFragmentManager.commit {
-					replace(R.id.container, PagerReaderFragment())
-				}
-			}
+		if (readerManager.currentMode != mode) {
+			readerManager.replace(mode)
 		}
-		binding.toolbarBottom.menu.findItem(R.id.action_reader_mode).setIcon(
-			when (mode) {
-				ReaderMode.WEBTOON -> R.drawable.ic_script
-				ReaderMode.REVERSED -> R.drawable.ic_read_reversed
-				ReaderMode.STANDARD -> R.drawable.ic_book_page
-			}
-		)
-		binding.appbarTop.postDelayed(1000) {
-			setUiIsVisible(false)
+		val iconRes = when (mode) {
+			ReaderMode.WEBTOON -> R.drawable.ic_script
+			ReaderMode.REVERSED -> R.drawable.ic_read_reversed
+			ReaderMode.STANDARD -> R.drawable.ic_book_page
+		}
+		binding.toolbarBottom.menu.findItem(R.id.action_reader_mode).run {
+			setIcon(iconRes)
+			setVisible(true)
+		}
+		if (binding.appbarTop.isVisible) {
+			lifecycle.postDelayed(hideUiRunnable, TimeUnit.SECONDS.toMillis(1))
 		}
 	}
 
@@ -151,18 +139,8 @@ class ReaderActivity :
 	override fun onOptionsItemSelected(item: MenuItem): Boolean {
 		when (item.itemId) {
 			R.id.action_reader_mode -> {
-				ReaderConfigDialog.show(
-					supportFragmentManager,
-					when (reader) {
-						is PagerReaderFragment -> ReaderMode.STANDARD
-						is WebtoonReaderFragment -> ReaderMode.WEBTOON
-						is ReversedReaderFragment -> ReaderMode.REVERSED
-						else -> {
-							showWaitWhileLoading()
-							return false
-						}
-					}
-				)
+				val currentMode = readerManager.currentMode ?: return false
+				ReaderConfigDialog.show(supportFragmentManager, currentMode)
 			}
 			R.id.action_settings -> {
 				startActivity(SettingsActivity.newReaderSettingsIntent(this))
@@ -184,17 +162,17 @@ class ReaderActivity :
 						supportFragmentManager,
 						pages,
 						title?.toString().orEmpty(),
-						reader?.getCurrentState()?.page ?: -1
+						readerManager.currentReader?.getCurrentState()?.page ?: -1,
 					)
 				} else {
-					showWaitWhileLoading()
+					return false
 				}
 			}
 			R.id.action_save_page -> {
 				viewModel.getCurrentPage()?.also { page ->
-					viewModel.saveCurrentState(reader?.getCurrentState())
+					viewModel.saveCurrentState(readerManager.currentReader?.getCurrentState())
 					viewModel.saveCurrentPage(page, savePageRequest)
-				} ?: showWaitWhileLoading()
+				} ?: return false
 			}
 			R.id.action_bookmark -> {
 				if (viewModel.isBookmarkAdded.value == true) {
@@ -216,10 +194,14 @@ class ReaderActivity :
 		val hasPages = !viewModel.content.value?.pages.isNullOrEmpty()
 		binding.layoutLoading.isVisible = isLoading && !hasPages
 		if (isLoading && hasPages) {
-			binding.toastView.show(R.string.loading_, true)
+			binding.toastView.show(R.string.loading_)
 		} else {
 			binding.toastView.hide()
 		}
+		val menu = binding.toolbarBottom.menu
+		menu.findItem(R.id.action_bookmark).isVisible = hasPages
+		menu.findItem(R.id.action_pages_thumbs).isVisible = hasPages
+		menu.findItem(R.id.action_save_page).isVisible = hasPages
 	}
 
 	private fun onError(e: Throwable) {
@@ -279,14 +261,14 @@ class ReaderActivity :
 			val index = pages.indexOfFirst { it.id == page.id }
 			if (index != -1) {
 				withContext(Dispatchers.Main) {
-					reader?.switchPageTo(index, true)
+					readerManager.currentReader?.switchPageTo(index, true)
 				}
 			}
 		}
 	}
 
 	override fun onReaderModeChanged(mode: ReaderMode) {
-		viewModel.saveCurrentState(reader?.getCurrentState())
+		viewModel.saveCurrentState(readerManager.currentReader?.getCurrentState())
 		viewModel.switchMode(mode)
 	}
 
@@ -304,12 +286,6 @@ class ReaderActivity :
 		}
 	}
 
-	private fun showWaitWhileLoading() {
-		Toast.makeText(this, R.string.wait_for_loading_finish, Toast.LENGTH_SHORT).apply {
-			setGravity(Gravity.CENTER, 0, 0)
-		}.show()
-	}
-
 	private fun setWindowSecure(isSecure: Boolean) {
 		if (isSecure) {
 			window.addFlags(WindowManager.LayoutParams.FLAG_SECURE)
@@ -358,7 +334,7 @@ class ReaderActivity :
 	override fun onWindowInsetsChanged(insets: Insets) = Unit
 
 	override fun switchPageBy(delta: Int) {
-		reader?.switchPageBy(delta)
+		readerManager.currentReader?.switchPageBy(delta)
 	}
 
 	override fun toggleUiVisibility() {

app/src/main/java/org/koitharu/kotatsu/reader/ui/ReaderControlDelegate.kt

@@ -5,14 +5,16 @@ import android.view.SoundEffectConstants
 import android.view.View
 import androidx.lifecycle.LifecycleCoroutineScope
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.core.prefs.observeAsFlow
 import org.koitharu.kotatsu.utils.GridTouchHelper
 
-@Suppress("UNUSED_PARAMETER")
 class ReaderControlDelegate(
-	private val scope: LifecycleCoroutineScope,
-	private val settings: AppSettings,
+	scope: LifecycleCoroutineScope,
+	settings: AppSettings,
 	private val listener: OnInteractionListener
 ) {
 
@@ -20,12 +22,8 @@ class ReaderControlDelegate(
 	private var isVolumeKeysSwitchEnabled: Boolean = false
 
 	init {
-		settings.observe()
-			.filter { it == AppSettings.KEY_READER_SWITCHERS }
-			.map { settings.readerPageSwitch }
-			.onStart { emit(settings.readerPageSwitch) }
-			.distinctUntilChanged()
-			.flowOn(Dispatchers.IO)
+		settings.observeAsFlow(AppSettings.KEY_READER_SWITCHERS) { readerPageSwitch }
+			.flowOn(Dispatchers.Default)
 			.onEach {
 				isTapSwitchEnabled = AppSettings.PAGE_SWITCH_TAPS in it
 				isVolumeKeysSwitchEnabled = AppSettings.PAGE_SWITCH_VOLUME_KEYS in it
@@ -57,7 +55,7 @@ class ReaderControlDelegate(
 		}
 	}
 
-	fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean = when (keyCode) {
+	fun onKeyDown(keyCode: Int, @Suppress("UNUSED_PARAMETER") event: KeyEvent?): Boolean = when (keyCode) {
 		KeyEvent.KEYCODE_VOLUME_UP -> if (isVolumeKeysSwitchEnabled) {
 			listener.switchPageBy(-1)
 			true
@@ -92,9 +90,11 @@ class ReaderControlDelegate(
 		else -> false
 	}
 
-	fun onKeyUp(keyCode: Int, event: KeyEvent?): Boolean {
-		return (isVolumeKeysSwitchEnabled &&
-				(keyCode == KeyEvent.KEYCODE_VOLUME_DOWN || keyCode == KeyEvent.KEYCODE_VOLUME_UP))
+	fun onKeyUp(keyCode: Int, @Suppress("UNUSED_PARAMETER") event: KeyEvent?): Boolean {
+		return (
+			isVolumeKeysSwitchEnabled &&
+				(keyCode == KeyEvent.KEYCODE_VOLUME_DOWN || keyCode == KeyEvent.KEYCODE_VOLUME_UP)
+			)
 	}
 
 	interface OnInteractionListener {

app/src/main/java/org/koitharu/kotatsu/reader/ui/ReaderManager.kt

@@ -0,0 +1,45 @@
+package org.koitharu.kotatsu.reader.ui
+
+import androidx.annotation.IdRes
+import androidx.fragment.app.FragmentManager
+import androidx.fragment.app.commit
+import org.koitharu.kotatsu.core.prefs.ReaderMode
+import org.koitharu.kotatsu.reader.ui.pager.BaseReader
+import org.koitharu.kotatsu.reader.ui.pager.reversed.ReversedReaderFragment
+import org.koitharu.kotatsu.reader.ui.pager.standard.PagerReaderFragment
+import org.koitharu.kotatsu.reader.ui.pager.webtoon.WebtoonReaderFragment
+import java.util.*
+
+class ReaderManager(
+	private val fragmentManager: FragmentManager,
+	@IdRes private val containerResId: Int,
+) {
+
+	private val modeMap = EnumMap<ReaderMode, Class<out BaseReader<*>>>(ReaderMode::class.java)
+
+	init {
+		modeMap[ReaderMode.STANDARD] = PagerReaderFragment::class.java
+		modeMap[ReaderMode.REVERSED] = ReversedReaderFragment::class.java
+		modeMap[ReaderMode.WEBTOON] = WebtoonReaderFragment::class.java
+	}
+
+	val currentReader: BaseReader<*>?
+		get() = fragmentManager.findFragmentById(containerResId) as? BaseReader<*>
+
+	val currentMode: ReaderMode?
+		get() {
+			val readerClass = currentReader?.javaClass ?: return null
+			return modeMap.entries.find { it.value == readerClass }?.key
+		}
+
+	fun replace(newMode: ReaderMode) {
+		val readerClass = requireNotNull(modeMap[newMode])
+		fragmentManager.commit {
+			replace(containerResId, readerClass, null, null)
+		}
+	}
+
+	fun replace(reader: BaseReader<*>) {
+		fragmentManager.commit { replace(containerResId, reader) }
+	}
+}

app/src/main/java/org/koitharu/kotatsu/reader/ui/ReaderToastView.kt

@@ -1,13 +1,11 @@
 package org.koitharu.kotatsu.reader.ui
 
 import android.content.Context
-import android.graphics.Color
 import android.util.AttributeSet
 import android.view.Gravity
 import android.view.ViewGroup
 import androidx.annotation.StringRes
 import androidx.core.view.isVisible
-import androidx.swiperefreshlayout.widget.CircularProgressDrawable
 import androidx.transition.Fade
 import androidx.transition.Slide
 import androidx.transition.TransitionManager
@@ -15,26 +13,28 @@ import androidx.transition.TransitionSet
 import com.google.android.material.textview.MaterialTextView
 
 class ReaderToastView @JvmOverloads constructor(
-	context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
+	context: Context,
+	attrs: AttributeSet? = null,
+	defStyleAttr: Int = 0,
 ) : MaterialTextView(context, attrs, defStyleAttr) {
 
 	private var hideRunnable = Runnable {
 		hide()
 	}
 
-	fun show(message: CharSequence, isLoading: Boolean) {
+	fun show(message: CharSequence) {
 		removeCallbacks(hideRunnable)
 		text = message
 		setupTransition()
 		isVisible = true
 	}
 
-	fun show(@StringRes messageId: Int, isLoading: Boolean) {
-		show(context.getString(messageId), isLoading)
+	fun show(@StringRes messageId: Int) {
+		show(context.getString(messageId))
 	}
 
 	fun showTemporary(message: CharSequence, duration: Long) {
-		show(message, false)
+		show(message)
 		postDelayed(hideRunnable, duration)
 	}
 
@@ -49,7 +49,7 @@ class ReaderToastView @JvmOverloads constructor(
 		super.onDetachedFromWindow()
 	}
 
-	private fun setupTransition () {
+	private fun setupTransition() {
 		val parentView = parent as? ViewGroup ?: return
 		val transition = TransitionSet()
 			.setOrdering(TransitionSet.ORDERING_TOGETHER)
@@ -58,14 +58,4 @@ class ReaderToastView @JvmOverloads constructor(
 			.addTransition(Fade())
 		TransitionManager.beginDelayedTransition(parentView, transition)
 	}
-
-	// FIXME use it as compound drawable
-	private fun createProgressDrawable(): CircularProgressDrawable {
-		val drawable = CircularProgressDrawable(context)
-		drawable.setStyle(CircularProgressDrawable.DEFAULT)
-		drawable.arrowEnabled = false
-		drawable.setColorSchemeColors(Color.WHITE)
-		drawable.centerRadius = lineHeight / 3f
-		return drawable
-	}
 }

app/src/main/java/org/koitharu/kotatsu/reader/ui/ReaderViewModel.kt

@@ -8,9 +8,6 @@ import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.*
 import kotlinx.coroutines.flow.*
-import org.koin.core.component.KoinComponent
-import org.koin.core.component.get
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.domain.MangaDataRepository
 import org.koitharu.kotatsu.base.domain.MangaIntent
@@ -21,22 +18,25 @@ import org.koitharu.kotatsu.bookmarks.domain.BookmarksRepository
 import org.koitharu.kotatsu.core.exceptions.MangaNotFoundException
 import org.koitharu.kotatsu.core.os.ShortcutsRepository
 import org.koitharu.kotatsu.core.parser.MangaRepository
-import org.koitharu.kotatsu.core.prefs.AppSettings
-import org.koitharu.kotatsu.core.prefs.ReaderMode
-import org.koitharu.kotatsu.core.prefs.ScreenshotsPolicy
+import org.koitharu.kotatsu.core.prefs.*
 import org.koitharu.kotatsu.history.domain.HistoryRepository
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaChapter
 import org.koitharu.kotatsu.parsers.model.MangaPage
+import org.koitharu.kotatsu.reader.data.filterChapters
 import org.koitharu.kotatsu.reader.domain.PageLoader
 import org.koitharu.kotatsu.reader.ui.pager.ReaderPage
 import org.koitharu.kotatsu.reader.ui.pager.ReaderUiState
 import org.koitharu.kotatsu.utils.SingleLiveEvent
-import org.koitharu.kotatsu.utils.ext.IgnoreErrors
 import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 import org.koitharu.kotatsu.utils.ext.processLifecycleScope
 import java.util.*
 
+private const val BOUNDS_PAGE_OFFSET = 2
+private const val PAGES_TRIM_THRESHOLD = 120
+private const val PREFETCH_LIMIT = 10
+
 class ReaderViewModel(
 	private val intent: MangaIntent,
 	initialState: ReaderState?,
@@ -78,22 +78,19 @@ class ReaderViewModel(
 	val manga: Manga?
 		get() = mangaData.value
 
-	val readerAnimation = settings.observe()
-		.filter { it == AppSettings.KEY_READER_ANIMATION }
-		.map { settings.readerAnimation }
-		.onStart { emit(settings.readerAnimation) }
-		.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.IO)
+	val readerAnimation = settings.observeAsLiveData(
+		context = viewModelScope.coroutineContext + Dispatchers.Default,
+		key = AppSettings.KEY_READER_ANIMATION,
+		valueProducer = { readerAnimation }
+	)
 
 	val isScreenshotsBlockEnabled = combine(
 		mangaData,
-		settings.observe()
-			.filter { it == AppSettings.KEY_SCREENSHOTS_POLICY }
-			.onStart { emit("") }
-			.map { settings.screenshotsPolicy },
+		settings.observeAsFlow(AppSettings.KEY_SCREENSHOTS_POLICY) { screenshotsPolicy },
 	) { manga, policy ->
 		policy == ScreenshotsPolicy.BLOCK_ALL ||
 			(policy == ScreenshotsPolicy.BLOCK_NSFW && manga != null && manga.isNsfw)
-	}.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.IO)
+	}.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.Default)
 
 	val onZoomChanged = SingleLiveEvent<Unit>()
 
@@ -142,7 +139,7 @@ class ReaderViewModel(
 		if (state != null) {
 			currentState.value = state
 		}
-		saveState(
+		historyRepository.saveStateAsync(
 			mangaData.value ?: return,
 			state ?: currentState.value ?: return
 		)
@@ -169,9 +166,7 @@ class ReaderViewModel(
 			} catch (e: CancellationException) {
 				throw e
 			} catch (e: Exception) {
-				if (BuildConfig.DEBUG) {
-					e.printStackTrace()
-				}
+				e.printStackTraceDebug()
 				onPageSaved.postCall(null)
 			}
 		}
@@ -286,7 +281,7 @@ class ReaderViewModel(
 			}
 
 			val branch = chapters[currentState.value?.chapterId ?: 0L].branch
-			mangaData.value = manga.copy(chapters = manga.chapters?.filter { it.branch == branch })
+			mangaData.value = manga.filterChapters(branch)
 			readerMode.postValue(mode)
 
 			val pages = loadChapter(requireNotNull(currentState.value).chapterId)
@@ -349,9 +344,9 @@ class ReaderViewModel(
 
 	private fun subscribeToSettings() {
 		settings.observe()
-			.filter { it == AppSettings.KEY_ZOOM_MODE }
-			.onEach { onZoomChanged.postCall(Unit) }
-			.launchIn(viewModelScope + Dispatchers.IO)
+			.onEach { key ->
+				if (key == AppSettings.KEY_ZOOM_MODE) onZoomChanged.postCall(Unit)
+			}.launchIn(viewModelScope + Dispatchers.Default)
 	}
 
 	private fun <T> List<T>.trySublist(fromIndex: Int, toIndex: Int): List<T> {
@@ -363,40 +358,23 @@ class ReaderViewModel(
 			subList(fromIndexBounded, toIndexBounded)
 		}
 	}
+}
 
-	private fun Manga.copy(chapters: List<MangaChapter>?) = Manga(
-		id = id,
-		title = title,
-		altTitle = altTitle,
-		url = url,
-		publicUrl = publicUrl,
-		rating = rating,
-		isNsfw = isNsfw,
-		coverUrl = coverUrl,
-		tags = tags,
-		state = state,
-		author = author,
-		largeCoverUrl = largeCoverUrl,
-		description = description,
-		chapters = chapters,
-		source = source,
-	)
-
-	private companion object : KoinComponent {
-
-		const val BOUNDS_PAGE_OFFSET = 2
-		const val PAGES_TRIM_THRESHOLD = 120
-		const val PREFETCH_LIMIT = 10
-
-		fun saveState(manga: Manga, state: ReaderState) {
-			processLifecycleScope.launch(Dispatchers.Default + IgnoreErrors) {
-				get<HistoryRepository>().addOrUpdate(
-					manga = manga,
-					chapterId = state.chapterId,
-					page = state.page,
-					scroll = state.scroll
-				)
-			}
+/**
+ * This function is not a member of the ReaderViewModel
+ * because it should work independently of the ViewModel's lifecycle.
+ */
+private fun HistoryRepository.saveStateAsync(manga: Manga, state: ReaderState): Job {
+	return processLifecycleScope.launch(Dispatchers.Default) {
+		runCatching {
+			addOrUpdate(
+				manga = manga,
+				chapterId = state.chapterId,
+				page = state.page,
+				scroll = state.scroll
+			)
+		}.onFailure {
+			it.printStackTraceDebug()
 		}
 	}
 }

app/src/main/java/org/koitharu/kotatsu/remotelist/ui/RemoteListViewModel.kt

@@ -6,7 +6,6 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.cancelAndJoin
 import kotlinx.coroutines.flow.*
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.domain.MangaDataRepository
 import org.koitharu.kotatsu.base.ui.widgets.ChipsView
@@ -21,6 +20,7 @@ import org.koitharu.kotatsu.list.ui.model.*
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaTag
 import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 
 private const val FILTER_MIN_INTERVAL = 750L
 
@@ -133,9 +133,7 @@ class RemoteListViewModel(
 				}
 				hasNextPage.value = list.isNotEmpty()
 			} catch (e: Throwable) {
-				if (BuildConfig.DEBUG) {
-					e.printStackTrace()
-				}
+				e.printStackTraceDebug()
 				listError.value = e
 				if (!mangaList.value.isNullOrEmpty()) {
 					onError.postCall(e)
@@ -158,4 +156,4 @@ class RemoteListViewModel(
 		textSecondary = 0,
 		actionStringRes = if (filterState.tags.isEmpty()) 0 else R.string.reset_filter,
 	)
-}
+}

app/src/main/java/org/koitharu/kotatsu/settings/AppUpdateChecker.kt

@@ -8,15 +8,6 @@ import android.net.Uri
 import androidx.activity.ComponentActivity
 import androidx.annotation.MainThread
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
-import java.io.ByteArrayInputStream
-import java.io.InputStream
-import java.security.MessageDigest
-import java.security.NoSuchAlgorithmException
-import java.security.cert.CertificateEncodingException
-import java.security.cert.CertificateException
-import java.security.cert.CertificateFactory
-import java.security.cert.X509Certificate
-import java.util.concurrent.TimeUnit
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import org.koin.android.ext.android.get
@@ -28,6 +19,16 @@ import org.koitharu.kotatsu.core.github.VersionId
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.parsers.util.byte2HexFormatted
 import org.koitharu.kotatsu.utils.FileSize
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
+import java.io.ByteArrayInputStream
+import java.io.InputStream
+import java.security.MessageDigest
+import java.security.NoSuchAlgorithmException
+import java.security.cert.CertificateEncodingException
+import java.security.cert.CertificateException
+import java.security.cert.CertificateFactory
+import java.security.cert.X509Certificate
+import java.util.concurrent.TimeUnit
 
 class AppUpdateChecker(private val activity: ComponentActivity) {
 
@@ -45,8 +46,8 @@ class AppUpdateChecker(private val activity: ComponentActivity) {
 
 	suspend fun checkNow() = runCatching {
 		val version = repo.getLatestVersion()
-		val newVersionId = VersionId.parse(version.name)
-		val currentVersionId = VersionId.parse(BuildConfig.VERSION_NAME)
+		val newVersionId = VersionId(version.name)
+		val currentVersionId = VersionId(BuildConfig.VERSION_NAME)
 		val result = newVersionId > currentVersionId
 		if (result) {
 			withContext(Dispatchers.Main) {
@@ -56,7 +57,7 @@ class AppUpdateChecker(private val activity: ComponentActivity) {
 		settings.lastUpdateCheckTimestamp = System.currentTimeMillis()
 		result
 	}.onFailure {
-		it.printStackTrace()
+		it.printStackTraceDebug()
 	}.getOrNull()
 
 	@MainThread
@@ -99,7 +100,7 @@ class AppUpdateChecker(private val activity: ComponentActivity) {
 					PackageManager.GET_SIGNATURES
 				)
 			} catch (e: PackageManager.NameNotFoundException) {
-				e.printStackTrace()
+				e.printStackTraceDebug()
 				return null
 			}
 			val signatures = packageInfo?.signatures
@@ -109,7 +110,7 @@ class AppUpdateChecker(private val activity: ComponentActivity) {
 				val cf = CertificateFactory.getInstance("X509")
 				cf.generateCertificate(input) as X509Certificate
 			} catch (e: CertificateException) {
-				e.printStackTrace()
+				e.printStackTraceDebug()
 				return null
 			}
 			return try {
@@ -117,10 +118,10 @@ class AppUpdateChecker(private val activity: ComponentActivity) {
 				val publicKey: ByteArray = md.digest(c.encoded)
 				publicKey.byte2HexFormatted()
 			} catch (e: NoSuchAlgorithmException) {
-				e.printStackTrace()
+				e.printStackTraceDebug()
 				null
 			} catch (e: CertificateEncodingException) {
-				e.printStackTrace()
+				e.printStackTraceDebug()
 				null
 			}
 		}

app/src/main/java/org/koitharu/kotatsu/settings/SourceSettingsFragment.kt

@@ -6,7 +6,6 @@ import androidx.preference.Preference
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.ui.BasePreferenceFragment
 import org.koitharu.kotatsu.core.parser.MangaRepository
@@ -14,6 +13,7 @@ import org.koitharu.kotatsu.core.parser.RemoteMangaRepository
 import org.koitharu.kotatsu.parsers.exception.AuthRequiredException
 import org.koitharu.kotatsu.parsers.model.MangaSource
 import org.koitharu.kotatsu.settings.sources.auth.SourceAuthActivity
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 import org.koitharu.kotatsu.utils.ext.serializableArgument
 import org.koitharu.kotatsu.utils.ext.viewLifecycleScope
 import org.koitharu.kotatsu.utils.ext.withArgs
@@ -70,9 +70,7 @@ class SourceSettingsFragment : BasePreferenceFragment(0) {
 			preference.title = getString(R.string.logged_in_as, username)
 		}.onFailure { error ->
 			preference.isEnabled = error is AuthRequiredException
-			if (BuildConfig.DEBUG) {
-				error.printStackTrace()
-			}
+			error.printStackTraceDebug()
 		}
 	}
 

app/src/main/java/org/koitharu/kotatsu/settings/backup/BackupSettingsFragment.kt

@@ -7,12 +7,13 @@ import androidx.activity.result.ActivityResultCallback
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.preference.Preference
 import com.google.android.material.snackbar.Snackbar
-import org.koitharu.kotatsu.BuildConfig
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.ui.BasePreferenceFragment
 import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 
-class BackupSettingsFragment : BasePreferenceFragment(R.string.backup_restore),
+class BackupSettingsFragment :
+	BasePreferenceFragment(R.string.backup_restore),
 	ActivityResultCallback<Uri?> {
 
 	private val backupSelectCall = registerForActivityResult(
@@ -34,9 +35,7 @@ class BackupSettingsFragment : BasePreferenceFragment(R.string.backup_restore),
 				try {
 					backupSelectCall.launch(arrayOf("*/*"))
 				} catch (e: ActivityNotFoundException) {
-					if (BuildConfig.DEBUG) {
-						e.printStackTrace()
-					}
+					e.printStackTraceDebug()
 					Snackbar.make(
 						listView, R.string.operation_not_supported, Snackbar.LENGTH_SHORT
 					).show()

app/src/main/java/org/koitharu/kotatsu/utils/LifecycleAwareServiceConnection.kt

@@ -10,7 +10,7 @@ import androidx.lifecycle.LifecycleOwner
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 
-class LifecycleAwareServiceConnection private constructor(
+class LifecycleAwareServiceConnection(
 	private val host: Activity,
 ) : ServiceConnection, DefaultLifecycleObserver {
 
@@ -31,19 +31,15 @@ class LifecycleAwareServiceConnection private constructor(
 		super.onDestroy(owner)
 		host.unbindService(this)
 	}
+}
 
-	companion object {
-
-		fun bindService(
-			host: Activity,
-			lifecycleOwner: LifecycleOwner,
-			service: Intent,
-			flags: Int,
-		): LifecycleAwareServiceConnection {
-			val connection = LifecycleAwareServiceConnection(host)
-			host.bindService(service, connection, flags)
-			lifecycleOwner.lifecycle.addObserver(connection)
-			return connection
-		}
-	}
+fun Activity.bindServiceWithLifecycle(
+	owner: LifecycleOwner,
+	service: Intent,
+	flags: Int
+): LifecycleAwareServiceConnection {
+	val connection = LifecycleAwareServiceConnection(this)
+	bindService(service, connection, flags)
+	owner.lifecycle.addObserver(connection)
+	return connection
 }

app/src/main/java/org/koitharu/kotatsu/utils/ext/AndroidExt.kt

@@ -9,7 +9,11 @@ import android.net.Uri
 import android.os.Build
 import androidx.activity.result.ActivityResultLauncher
 import androidx.core.app.ActivityOptionsCompat
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.coroutineScope
 import androidx.work.CoroutineWorker
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
 import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlin.coroutines.resume
 
@@ -55,4 +59,11 @@ fun <I> ActivityResultLauncher<I>.tryLaunch(input: I, options: ActivityOptionsCo
 	return runCatching {
 		launch(input, options)
 	}.isSuccess
+}
+
+fun Lifecycle.postDelayed(runnable: Runnable, delay: Long) {
+	coroutineScope.launch {
+		delay(delay)
+		runnable.run()
+	}
 }

app/src/main/java/org/koitharu/kotatsu/utils/ext/CoroutineExt.kt

@@ -3,15 +3,6 @@ package org.koitharu.kotatsu.utils.ext
 import androidx.lifecycle.LifecycleCoroutineScope
 import androidx.lifecycle.ProcessLifecycleOwner
 import androidx.lifecycle.lifecycleScope
-import kotlinx.coroutines.CoroutineExceptionHandler
-import org.koitharu.kotatsu.BuildConfig
-
-val IgnoreErrors
-	get() = CoroutineExceptionHandler { _, e ->
-		if (BuildConfig.DEBUG) {
-			e.printStackTrace()
-		}
-	}
 
 val processLifecycleScope: LifecycleCoroutineScope
 	inline get() = ProcessLifecycleOwner.get().lifecycleScope

app/src/main/java/org/koitharu/kotatsu/utils/ext/LiveDataExt.kt

@@ -4,6 +4,7 @@ import androidx.lifecycle.LifecycleOwner
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.Observer
 import androidx.lifecycle.liveData
+import kotlinx.coroutines.Deferred
 import kotlin.coroutines.CoroutineContext
 import kotlin.coroutines.EmptyCoroutineContext
 import kotlinx.coroutines.flow.Flow

app/src/main/res/menu/opt_reader_bottom.xml

@@ -9,12 +9,14 @@
 		android:id="@+id/action_bookmark"
 		android:icon="@drawable/ic_bookmark"
 		android:title="@string/bookmark_add"
+		android:visible="false"
 		app:showAsAction="always" />
 
 	<item
 		android:id="@+id/action_pages_thumbs"
 		android:icon="@drawable/ic_grid"
 		android:title="@string/pages"
+		android:visible="false"
 		app:showAsAction="always" />
 
 	<item
@@ -28,11 +30,13 @@
 		android:id="@+id/action_reader_mode"
 		android:icon="@drawable/ic_loading"
 		android:title="@string/read_mode"
+		android:visible="false"
 		app:showAsAction="always" />
 
 	<item
 		android:id="@+id/action_save_page"
 		android:title="@string/save_page"
+		android:visible="false"
 		app:showAsAction="never" />
 
 	<item

app/src/release/java/org/koitharu/kotatsu/utils/ext/DebugExt.kt

@@ -0,0 +1,5 @@
+package org.koitharu.kotatsu.utils.ext
+
+import org.koitharu.kotatsu.BuildConfig
+
+inline fun Throwable.printStackTraceDebug() = Unit