Merge branch 'feature/suggestions_v2' into devel

app/src/main/java/org/koitharu/kotatsu/core/model/Manga.kt

@@ -9,6 +9,8 @@ import org.koitharu.kotatsu.utils.ext.iterator
 
 fun Collection<Manga>.ids() = mapToSet { it.id }
 
+fun Collection<Manga>.distinctById() = distinctBy { it.id }
+
 fun Collection<ChapterListItem>.countChaptersByBranch(): Int {
 	if (size <= 1) {
 		return size

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

@@ -16,6 +16,7 @@ import org.koitharu.kotatsu.core.model.ZoomMode
 import org.koitharu.kotatsu.core.network.DoHProvider
 import org.koitharu.kotatsu.parsers.model.MangaSource
 import org.koitharu.kotatsu.parsers.model.SortOrder
+import org.koitharu.kotatsu.parsers.util.mapToSet
 import org.koitharu.kotatsu.shelf.domain.ShelfSection
 import org.koitharu.kotatsu.utils.ext.connectivityManager
 import org.koitharu.kotatsu.utils.ext.filterToSet
@@ -244,12 +245,25 @@ class AppSettings @Inject constructor(@ApplicationContext context: Context) {
 	val isDownloadsWiFiOnly: Boolean
 		get() = prefs.getBoolean(KEY_DOWNLOADS_WIFI, false)
 
-	val isSuggestionsEnabled: Boolean
+	var isSuggestionsEnabled: Boolean
 		get() = prefs.getBoolean(KEY_SUGGESTIONS, false)
+		set(value) = prefs.edit { putBoolean(KEY_SUGGESTIONS, value) }
 
 	val isSuggestionsExcludeNsfw: Boolean
 		get() = prefs.getBoolean(KEY_SUGGESTIONS_EXCLUDE_NSFW, false)
 
+	val isSuggestionsNotificationAvailable: Boolean
+		get() = prefs.getBoolean(KEY_SUGGESTIONS_NOTIFICATIONS, true)
+
+	val suggestionsTagsBlacklist: Set<String>
+		get() {
+			val string = prefs.getString(KEY_SUGGESTIONS_EXCLUDE_TAGS, null)?.trimEnd(' ', ',')
+			if (string.isNullOrEmpty()) {
+				return emptySet()
+			}
+			return string.split(',').mapToSet { it.trim() }
+		}
+
 	val isReaderBarEnabled: Boolean
 		get() = prefs.getBoolean(KEY_READER_BAR, true)
 
@@ -279,18 +293,6 @@ class AppSettings @Inject constructor(@ApplicationContext context: Context) {
 		return policy.isNetworkAllowed(connectivityManager)
 	}
 
-	fun getSuggestionsTagsBlacklistRegex(): Regex? {
-		val string = prefs.getString(KEY_SUGGESTIONS_EXCLUDE_TAGS, null)?.trimEnd(' ', ',')
-		if (string.isNullOrEmpty()) {
-			return null
-		}
-		val tags = string.split(',')
-		val regex = tags.joinToString(prefix = "(", separator = "|", postfix = ")") { tag ->
-			Regex.escape(tag.trim())
-		}
-		return Regex(regex, RegexOption.IGNORE_CASE)
-	}
-
 	fun getMangaSources(includeHidden: Boolean): List<MangaSource> {
 		val list = remoteSources.toMutableList()
 		val order = sourcesOrder
@@ -381,6 +383,7 @@ class AppSettings @Inject constructor(@ApplicationContext context: Context) {
 		const val KEY_SUGGESTIONS = "suggestions"
 		const val KEY_SUGGESTIONS_EXCLUDE_NSFW = "suggestions_exclude_nsfw"
 		const val KEY_SUGGESTIONS_EXCLUDE_TAGS = "suggestions_exclude_tags"
+		const val KEY_SUGGESTIONS_NOTIFICATIONS = "suggestions_notifications"
 		const val KEY_SHIKIMORI = "shikimori"
 		const val KEY_ANILIST = "anilist"
 		const val KEY_MAL = "mal"

app/src/main/java/org/koitharu/kotatsu/explore/domain/ExploreRepository.kt

@@ -1,11 +1,16 @@
 package org.koitharu.kotatsu.explore.domain
 
-import javax.inject.Inject
 import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.history.domain.HistoryRepository
 import org.koitharu.kotatsu.parsers.model.Manga
-import org.koitharu.kotatsu.parsers.model.SortOrder
+import org.koitharu.kotatsu.parsers.model.MangaSource
+import org.koitharu.kotatsu.suggestions.domain.TagsBlacklist
+import org.koitharu.kotatsu.utils.ext.almostEquals
+import org.koitharu.kotatsu.utils.ext.asArrayList
+import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
+import org.koitharu.kotatsu.utils.ext.runCatchingCancellable
+import javax.inject.Inject
 
 class ExploreRepository @Inject constructor(
 	private val settings: AppSettings,
@@ -14,29 +19,47 @@ class ExploreRepository @Inject constructor(
 ) {
 
 	suspend fun findRandomManga(tagsLimit: Int): Manga {
-		val blacklistTagRegex = settings.getSuggestionsTagsBlacklistRegex()
-		val allTags = historyRepository.getPopularTags(tagsLimit).filterNot {
-			blacklistTagRegex?.containsMatchIn(it.title) ?: false
+		val blacklistTagRegex = TagsBlacklist(settings.suggestionsTagsBlacklist, 0.4f)
+		val tags = historyRepository.getPopularTags(tagsLimit).mapNotNull {
+			if (it in blacklistTagRegex) null else it.title
 		}
-		val tag = allTags.randomOrNull()
-		val source = checkNotNull(tag?.source ?: settings.getMangaSources(includeHidden = false).randomOrNull()) {
-			"No sources found"
-		}
-		val repo = mangaRepositoryFactory.create(source)
-		val list = repo.getList(
-			offset = 0,
-			sortOrder = if (SortOrder.UPDATED in repo.sortOrders) SortOrder.UPDATED else null,
-			tags = setOfNotNull(tag),
-		).shuffled()
-		for (item in list) {
-			if (settings.isSuggestionsExcludeNsfw && item.isNsfw) {
+		val sources = settings.getMangaSources(includeHidden = false)
+		check(sources.isNotEmpty()) { "No sources available" }
+		for (i in 0..4) {
+			val list = getList(sources.random(), tags, blacklistTagRegex)
+			val manga = list.randomOrNull() ?: continue
+			val details = runCatchingCancellable {
+				mangaRepositoryFactory.create(manga.source).getDetails(manga)
+			}.getOrNull() ?: continue
+			if ((settings.isSuggestionsExcludeNsfw && details.isNsfw) || details in blacklistTagRegex) {
 				continue
 			}
-			if (blacklistTagRegex != null && item.tags.any { x -> blacklistTagRegex.containsMatchIn(x.title) }) {
-				continue
-			}
-			return item
+			return details
 		}
-		return list.random()
+		throw NoSuchElementException()
 	}
+
+	private suspend fun getList(
+		source: MangaSource,
+		tags: List<String>,
+		blacklist: TagsBlacklist,
+	): List<Manga> = runCatchingCancellable {
+		val repository = mangaRepositoryFactory.create(source)
+		val order = repository.sortOrders.random()
+		val availableTags = repository.getTags()
+		val tag = tags.firstNotNullOfOrNull { title ->
+			availableTags.find { x -> x.title.almostEquals(title, 0.4f) }
+		}
+		val list = repository.getList(0, setOfNotNull(tag), order).asArrayList()
+		if (settings.isSuggestionsExcludeNsfw) {
+			list.removeAll { it.isNsfw }
+		}
+		if (blacklist.isNotEmpty()) {
+			list.removeAll { manga -> manga in blacklist }
+		}
+		list.shuffle()
+		list
+	}.onFailure {
+		it.printStackTraceDebug()
+	}.getOrDefault(emptyList())
 }

app/src/main/java/org/koitharu/kotatsu/explore/ui/ExploreFragment.kt

@@ -1,5 +1,6 @@
 package org.koitharu.kotatsu.explore.ui
 
+import android.content.DialogInterface
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.MenuItem
@@ -16,6 +17,7 @@ import coil.ImageLoader
 import dagger.hilt.android.AndroidEntryPoint
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.ui.BaseFragment
+import org.koitharu.kotatsu.base.ui.dialog.TwoButtonsAlertDialog
 import org.koitharu.kotatsu.base.ui.list.OnListItemClickListener
 import org.koitharu.kotatsu.base.ui.util.RecyclerViewOwner
 import org.koitharu.kotatsu.base.ui.util.ReversibleActionObserver
@@ -76,6 +78,9 @@ class ExploreFragment :
 		viewModel.onOpenManga.observe(viewLifecycleOwner, ::onOpenManga)
 		viewModel.onActionDone.observe(viewLifecycleOwner, ReversibleActionObserver(binding.recyclerView))
 		viewModel.isGrid.observe(viewLifecycleOwner, ::onGridModeChanged)
+		viewModel.onShowSuggestionsTip.observe(viewLifecycleOwner) {
+			showSuggestionsTip()
+		}
 	}
 
 	override fun onDestroyView() {
@@ -143,6 +148,19 @@ class ExploreFragment :
 		activity?.invalidateOptionsMenu()
 	}
 
+	private fun showSuggestionsTip() {
+		val listener = DialogInterface.OnClickListener { _, which ->
+			viewModel.respondSuggestionTip(which == DialogInterface.BUTTON_POSITIVE)
+		}
+		TwoButtonsAlertDialog.Builder(requireContext())
+			.setIcon(R.drawable.ic_suggestion)
+			.setTitle(R.string.suggestions_enable_prompt)
+			.setPositiveButton(R.string.enable, listener)
+			.setNegativeButton(R.string.no_thanks, listener)
+			.create()
+			.show()
+	}
+
 	private inner class SourceMenuListener(
 		private val sourceItem: ExploreItem.Source,
 	) : PopupMenu.OnMenuItemClickListener {

app/src/main/java/org/koitharu/kotatsu/explore/ui/ExploreViewModel.kt

@@ -6,7 +6,6 @@ import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flowOf
@@ -27,6 +26,8 @@ import org.koitharu.kotatsu.utils.SingleLiveEvent
 import org.koitharu.kotatsu.utils.asFlowLiveData
 import javax.inject.Inject
 
+private const val TIP_SUGGESTIONS = "suggestions"
+
 @HiltViewModel
 class ExploreViewModel @Inject constructor(
 	private val settings: AppSettings,
@@ -41,6 +42,7 @@ class ExploreViewModel @Inject constructor(
 
 	val onOpenManga = SingleLiveEvent<Manga>()
 	val onActionDone = SingleLiveEvent<ReversibleAction>()
+	val onShowSuggestionsTip = SingleLiveEvent<Unit>()
 	val isGrid = gridMode.asFlowLiveData(viewModelScope.coroutineContext)
 
 	val content: LiveData<List<ExploreItem>> = isLoading.asFlow().flatMapLatest { loading ->
@@ -51,6 +53,14 @@ class ExploreViewModel @Inject constructor(
 		}
 	}.asFlowLiveData(viewModelScope.coroutineContext + Dispatchers.Default, listOf(ExploreItem.Loading))
 
+	init {
+		launchJob(Dispatchers.Default) {
+			if (!settings.isSuggestionsEnabled && settings.isTipEnabled(TIP_SUGGESTIONS)) {
+				onShowSuggestionsTip.emitCall(Unit)
+			}
+		}
+	}
+
 	fun openRandom() {
 		launchLoadingJob(Dispatchers.Default) {
 			val manga = exploreRepository.findRandomManga(tagsLimit = 8)
@@ -72,6 +82,11 @@ class ExploreViewModel @Inject constructor(
 		settings.isSourcesGridMode = value
 	}
 
+	fun respondSuggestionTip(isAccepted: Boolean) {
+		settings.isSuggestionsEnabled = isAccepted
+		settings.closeTip(TIP_SUGGESTIONS)
+	}
+
 	private fun createContentFlow() = settings.observe()
 		.filter {
 			it == AppSettings.KEY_SOURCES_HIDDEN ||
@@ -80,7 +95,6 @@ class ExploreViewModel @Inject constructor(
 		}
 		.onStart { emit("") }
 		.map { settings.getMangaSources(includeHidden = false) }
-		.distinctUntilChanged()
 		.combine(gridMode) { content, grid -> buildList(content, grid) }
 
 	private fun buildList(sources: List<MangaSource>, isGrid: Boolean): List<ExploreItem> {

app/src/main/java/org/koitharu/kotatsu/favourites/data/EntityMapping.kt

@@ -1,9 +1,11 @@
 package org.koitharu.kotatsu.favourites.data
 
 import org.koitharu.kotatsu.core.db.entity.SortOrder
+import org.koitharu.kotatsu.core.db.entity.toManga
+import org.koitharu.kotatsu.core.db.entity.toMangaTags
 import org.koitharu.kotatsu.core.model.FavouriteCategory
 import org.koitharu.kotatsu.parsers.model.SortOrder
-import java.util.*
+import java.util.Date
 
 fun FavouriteCategoryEntity.toFavouriteCategory(id: Long = categoryId.toLong()) = FavouriteCategory(
 	id = id,
@@ -13,4 +15,8 @@ fun FavouriteCategoryEntity.toFavouriteCategory(id: Long = categoryId.toLong())
 	createdAt = Date(createdAt),
 	isTrackingEnabled = track,
 	isVisibleInLibrary = isVisibleInLibrary,
-)
+)
+
+fun FavouriteManga.toManga() = manga.toManga(tags.toMangaTags())
+
+fun Collection<FavouriteManga>.toMangaList() = map { it.toManga() }

app/src/main/java/org/koitharu/kotatsu/favourites/data/FavouritesDao.kt

@@ -17,6 +17,10 @@ abstract class FavouritesDao {
 	@Query("SELECT * FROM favourites WHERE deleted_at = 0 GROUP BY manga_id ORDER BY created_at DESC")
 	abstract suspend fun findAll(): List<FavouriteManga>
 
+	@Transaction
+	@Query("SELECT * FROM favourites WHERE deleted_at = 0 GROUP BY manga_id ORDER BY created_at DESC LIMIT :limit")
+	abstract suspend fun findLast(limit: Int): List<FavouriteManga>
+
 	fun observeAll(order: SortOrder): Flow<List<FavouriteManga>> {
 		val orderBy = getOrderBy(order)
 

app/src/main/java/org/koitharu/kotatsu/favourites/domain/FavouritesRepository.kt

@@ -12,12 +12,12 @@ import org.koitharu.kotatsu.core.db.MangaDatabase
 import org.koitharu.kotatsu.core.db.entity.SortOrder
 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.toMangaTags
 import org.koitharu.kotatsu.core.model.FavouriteCategory
 import org.koitharu.kotatsu.favourites.data.FavouriteCategoryEntity
 import org.koitharu.kotatsu.favourites.data.FavouriteEntity
 import org.koitharu.kotatsu.favourites.data.toFavouriteCategory
+import org.koitharu.kotatsu.favourites.data.toManga
+import org.koitharu.kotatsu.favourites.data.toMangaList
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.SortOrder
 import org.koitharu.kotatsu.tracker.work.TrackerNotificationChannels
@@ -32,22 +32,27 @@ class FavouritesRepository @Inject constructor(
 
 	suspend fun getAllManga(): List<Manga> {
 		val entities = db.favouritesDao.findAll()
-		return entities.map { it.manga.toManga(it.tags.toMangaTags()) }
+		return entities.toMangaList()
+	}
+
+	suspend fun getLastManga(limit: Int): List<Manga> {
+		val entities = db.favouritesDao.findLast(limit)
+		return entities.toMangaList()
 	}
 
 	fun observeAll(order: SortOrder): Flow<List<Manga>> {
 		return db.favouritesDao.observeAll(order)
-			.mapItems { it.manga.toManga(it.tags.toMangaTags()) }
+			.mapItems { it.toManga() }
 	}
 
 	suspend fun getManga(categoryId: Long): List<Manga> {
 		val entities = db.favouritesDao.findAll(categoryId)
-		return entities.map { it.manga.toManga(it.tags.toMangaTags()) }
+		return entities.toMangaList()
 	}
 
 	fun observeAll(categoryId: Long, order: SortOrder): Flow<List<Manga>> {
 		return db.favouritesDao.observeAll(categoryId, order)
-			.mapItems { it.manga.toManga(it.tags.toMangaTags()) }
+			.mapItems { it.toManga() }
 	}
 
 	fun observeAll(categoryId: Long): Flow<List<Manga>> {

app/src/main/java/org/koitharu/kotatsu/suggestions/domain/SuggestionRepository.kt

@@ -1,7 +1,6 @@
 package org.koitharu.kotatsu.suggestions.domain
 
 import androidx.room.withTransaction
-import javax.inject.Inject
 import kotlinx.coroutines.flow.Flow
 import org.koitharu.kotatsu.core.db.MangaDatabase
 import org.koitharu.kotatsu.core.db.entity.toEntities
@@ -11,6 +10,7 @@ import org.koitharu.kotatsu.core.db.entity.toMangaTags
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.suggestions.data.SuggestionEntity
 import org.koitharu.kotatsu.utils.ext.mapItems
+import javax.inject.Inject
 
 class SuggestionRepository @Inject constructor(
 	private val db: MangaDatabase,

app/src/main/java/org/koitharu/kotatsu/suggestions/domain/TagsBlacklist.kt

@@ -0,0 +1,31 @@
+package org.koitharu.kotatsu.suggestions.domain
+
+import org.koitharu.kotatsu.parsers.model.Manga
+import org.koitharu.kotatsu.parsers.model.MangaTag
+import org.koitharu.kotatsu.utils.ext.almostEquals
+
+class TagsBlacklist(
+	private val tags: Set<String>,
+	private val threshold: Float,
+) {
+
+	fun isNotEmpty() = tags.isNotEmpty()
+
+	operator fun contains(manga: Manga): Boolean {
+		if (tags.isEmpty()) {
+			return false
+		}
+		for (mangaTag in manga.tags) {
+			for (tagTitle in tags) {
+				if (mangaTag.title.almostEquals(tagTitle, threshold)) {
+					return true
+				}
+			}
+		}
+		return false
+	}
+
+	operator fun contains(tag: MangaTag): Boolean = tags.any {
+		it.almostEquals(tag.title, threshold)
+	}
+}

app/src/main/java/org/koitharu/kotatsu/suggestions/ui/SuggestionsWorker.kt

@@ -2,11 +2,15 @@ package org.koitharu.kotatsu.suggestions.ui
 
 import android.app.NotificationChannel
 import android.app.NotificationManager
+import android.app.PendingIntent
 import android.content.Context
 import android.os.Build
 import androidx.annotation.FloatRange
 import androidx.core.app.NotificationCompat
-import androidx.core.content.ContextCompat
+import androidx.core.app.PendingIntentCompat
+import androidx.core.text.HtmlCompat
+import androidx.core.text.buildSpannedString
+import androidx.core.text.parseAsHtml
 import androidx.hilt.work.HiltWorker
 import androidx.work.BackoffPolicy
 import androidx.work.Constraints
@@ -20,39 +24,56 @@ import androidx.work.PeriodicWorkRequestBuilder
 import androidx.work.WorkManager
 import androidx.work.WorkerParameters
 import androidx.work.workDataOf
+import coil.ImageLoader
+import coil.request.ImageRequest
 import dagger.assisted.Assisted
 import dagger.assisted.AssistedInject
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.async
-import kotlinx.coroutines.awaitAll
-import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.flow.channelFlow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.take
+import kotlinx.coroutines.flow.toList
+import kotlinx.coroutines.launch
 import org.koitharu.kotatsu.R
+import org.koitharu.kotatsu.core.model.distinctById
 import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.details.ui.DetailsActivity
+import org.koitharu.kotatsu.favourites.domain.FavouritesRepository
 import org.koitharu.kotatsu.history.domain.HistoryRepository
+import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaSource
 import org.koitharu.kotatsu.parsers.model.MangaTag
 import org.koitharu.kotatsu.parsers.model.SortOrder
+import org.koitharu.kotatsu.reader.ui.ReaderActivity
 import org.koitharu.kotatsu.suggestions.domain.MangaSuggestion
 import org.koitharu.kotatsu.suggestions.domain.SuggestionRepository
+import org.koitharu.kotatsu.suggestions.domain.TagsBlacklist
+import org.koitharu.kotatsu.utils.ext.almostEquals
 import org.koitharu.kotatsu.utils.ext.asArrayList
+import org.koitharu.kotatsu.utils.ext.flatten
 import org.koitharu.kotatsu.utils.ext.printStackTraceDebug
 import org.koitharu.kotatsu.utils.ext.runCatchingCancellable
+import org.koitharu.kotatsu.utils.ext.takeMostFrequent
+import org.koitharu.kotatsu.utils.ext.toBitmapOrNull
 import org.koitharu.kotatsu.utils.ext.trySetForeground
 import java.util.concurrent.TimeUnit
 import kotlin.math.pow
+import kotlin.random.Random
 
 @HiltWorker
 class SuggestionsWorker @AssistedInject constructor(
 	@Assisted appContext: Context,
 	@Assisted params: WorkerParameters,
+	private val coil: ImageLoader,
 	private val suggestionRepository: SuggestionRepository,
 	private val historyRepository: HistoryRepository,
+	private val favouritesRepository: FavouritesRepository,
 	private val appSettings: AppSettings,
 	private val mangaRepositoryFactory: MangaRepository.Factory,
 ) : CoroutineWorker(appContext, params) {
 
 	override suspend fun doWork(): Result {
+		trySetForeground()
 		val count = doWorkImpl()
 		val outputData = workDataOf(DATA_COUNT to count)
 		return Result.success(outputData)
@@ -93,83 +114,197 @@ class SuggestionsWorker @AssistedInject constructor(
 			suggestionRepository.clear()
 			return 0
 		}
-		val blacklistTagRegex = appSettings.getSuggestionsTagsBlacklistRegex()
-		val allTags = historyRepository.getPopularTags(TAGS_LIMIT).filterNot {
-			blacklistTagRegex?.containsMatchIn(it.title) ?: false
-		}
-		if (allTags.isEmpty()) {
+		val seed = (
+			historyRepository.getList(0, 20) +
+				favouritesRepository.getLastManga(20)
+			).distinctById()
+		val sources = appSettings.getMangaSources(includeHidden = false)
+		if (seed.isEmpty() || sources.isEmpty()) {
 			return 0
 		}
-		if (TAG in tags) { // not expedited
-			trySetForeground()
-		}
-		val tagsBySources = allTags.groupBy { x -> x.source }
-		val dispatcher = Dispatchers.Default.limitedParallelism(MAX_PARALLELISM)
-		val rawResults = coroutineScope {
-			tagsBySources.flatMap { (source, tags) ->
-				val repo = mangaRepositoryFactory.tryCreate(source) ?: return@flatMap emptyList()
-				tags.map { tag ->
-					async(dispatcher) {
-						repo.getListSafe(tag)
-					}
+		val tagsBlacklist = TagsBlacklist(appSettings.suggestionsTagsBlacklist, TAG_EQ_THRESHOLD)
+		val tags = seed.flatMap { it.tags.map { x -> x.title } }.takeMostFrequent(10)
+
+		val producer = channelFlow {
+			for (it in sources.shuffled()) {
+				launch {
+					send(getList(it, tags, tagsBlacklist))
 				}
-			}.awaitAll().flatten().asArrayList()
-		}
-		if (appSettings.isSuggestionsExcludeNsfw) {
-			rawResults.removeAll { it.isNsfw }
-		}
-		if (blacklistTagRegex != null) {
-			rawResults.removeAll {
-				it.tags.any { x -> blacklistTagRegex.containsMatchIn(x.title) }
 			}
 		}
-		if (rawResults.isEmpty()) {
-			return 0
-		}
-		val suggestions = rawResults.distinctBy { manga ->
-			manga.id
-		}.map { manga ->
-			MangaSuggestion(
-				manga = manga,
-				relevance = computeRelevance(manga.tags, allTags),
-			)
-		}.sortedBy { it.relevance }.take(LIMIT)
+		val suggestions = producer
+			.flatten()
+			.take(MAX_RAW_RESULTS)
+			.map { manga ->
+				MangaSuggestion(
+					manga = manga,
+					relevance = computeRelevance(manga.tags, tags),
+				)
+			}.toList()
+			.sortedBy { it.relevance }
+			.take(MAX_RESULTS)
 		suggestionRepository.replace(suggestions)
+		if (appSettings.isSuggestionsNotificationAvailable) {
+			runCatchingCancellable {
+				val manga = suggestions[Random.nextInt(0, suggestions.size / 3)]
+				val details = mangaRepositoryFactory.create(manga.manga.source)
+					.getDetails(manga.manga)
+				if (details !in tagsBlacklist) {
+					showNotification(details)
+				}
+			}.onFailure {
+				it.printStackTraceDebug()
+			}
+		}
 		return suggestions.size
 	}
 
+	private suspend fun getList(
+		source: MangaSource,
+		tags: List<String>,
+		blacklist: TagsBlacklist,
+	): List<Manga> = runCatchingCancellable {
+		val repository = mangaRepositoryFactory.create(source)
+		val availableOrders = repository.sortOrders
+		val order = preferredSortOrders.first { it in availableOrders }
+		val availableTags = repository.getTags()
+		val tag = tags.firstNotNullOfOrNull { title ->
+			availableTags.find { x -> x.title.almostEquals(title, TAG_EQ_THRESHOLD) }
+		}
+		val list = repository.getList(0, setOfNotNull(tag), order).asArrayList()
+		if (appSettings.isSuggestionsExcludeNsfw) {
+			list.removeAll { it.isNsfw }
+		}
+		if (blacklist.isNotEmpty()) {
+			list.removeAll { manga -> manga in blacklist }
+		}
+		list
+	}.onFailure {
+		it.printStackTraceDebug()
+	}.getOrDefault(emptyList())
+
+	private suspend fun showNotification(manga: Manga) {
+		val manager = applicationContext.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+			val channel = NotificationChannel(
+				MANGA_CHANNEL_ID,
+				applicationContext.getString(R.string.suggestions),
+				NotificationManager.IMPORTANCE_DEFAULT,
+			)
+			channel.description = applicationContext.getString(R.string.suggestions_summary)
+			channel.enableLights(true)
+			channel.setShowBadge(true)
+			manager.createNotificationChannel(channel)
+		}
+		val id = manga.url.hashCode()
+		val title = applicationContext.getString(R.string.suggestion_manga, manga.title)
+		val builder = NotificationCompat.Builder(applicationContext, MANGA_CHANNEL_ID)
+		val tagsText = manga.tags.joinToString(", ") { it.title }
+		with(builder) {
+			setContentText(tagsText)
+			setContentTitle(title)
+			setLargeIcon(
+				coil.execute(
+					ImageRequest.Builder(applicationContext)
+						.data(manga.coverUrl)
+						.tag(manga.source)
+						.build(),
+				).toBitmapOrNull(),
+			)
+			setSmallIcon(R.drawable.ic_stat_suggestion)
+			val description = manga.description?.parseAsHtml(HtmlCompat.FROM_HTML_MODE_COMPACT)
+			if (!description.isNullOrBlank()) {
+				val style = NotificationCompat.BigTextStyle()
+				style.bigText(
+					buildSpannedString {
+						append(tagsText)
+						appendLine()
+						append(description)
+					},
+				)
+				style.setBigContentTitle(title)
+				setStyle(style)
+			}
+			val intent = DetailsActivity.newIntent(applicationContext, manga)
+			setContentIntent(
+				PendingIntentCompat.getActivity(
+					applicationContext,
+					id,
+					intent,
+					PendingIntent.FLAG_UPDATE_CURRENT,
+					false,
+				),
+			)
+			setAutoCancel(true)
+			setCategory(NotificationCompat.CATEGORY_RECOMMENDATION)
+			setVisibility(if (manga.isNsfw) NotificationCompat.VISIBILITY_SECRET else NotificationCompat.VISIBILITY_PUBLIC)
+			setShortcutId(manga.id.toString())
+			priority = NotificationCompat.PRIORITY_DEFAULT
+
+			addAction(
+				R.drawable.ic_read,
+				applicationContext.getString(R.string.read),
+				PendingIntentCompat.getActivity(
+					applicationContext,
+					id + 2,
+					ReaderActivity.newIntent(applicationContext, manga),
+					0,
+					false,
+				),
+			)
+
+			addAction(
+				R.drawable.ic_suggestion,
+				applicationContext.getString(R.string.more),
+				PendingIntentCompat.getActivity(
+					applicationContext,
+					0,
+					SuggestionsActivity.newIntent(applicationContext),
+					0,
+					false,
+				),
+			)
+		}
+		manager.notify(TAG, id, builder.build())
+	}
+
 	@FloatRange(from = 0.0, to = 1.0)
-	private fun computeRelevance(mangaTags: Set<MangaTag>, allTags: List<MangaTag>): Float {
+	private fun computeRelevance(mangaTags: Set<MangaTag>, allTags: List<String>): Float {
 		val maxWeight = (allTags.size + allTags.size + 1 - mangaTags.size) * mangaTags.size / 2.0
 		val weight = mangaTags.sumOf { tag ->
-			val index = allTags.indexOf(tag)
+			val index = allTags.inexactIndexOf(tag.title, TAG_EQ_THRESHOLD)
 			if (index < 0) 0 else allTags.size - index
 		}
 		return (weight / maxWeight).pow(2.0).toFloat()
 	}
 
-	private suspend fun MangaRepository.getListSafe(tag: MangaTag) = runCatchingCancellable {
-		getList(offset = 0, sortOrder = SortOrder.UPDATED, tags = setOf(tag))
-	}.onFailure { error ->
-		error.printStackTraceDebug()
-	}.getOrDefault(emptyList())
-
-	private fun MangaRepository.Factory.tryCreate(source: MangaSource) = runCatching {
-		create(source)
-	}.onFailure { error ->
-		error.printStackTraceDebug()
-	}.getOrNull()
+	private fun Iterable<String>.inexactIndexOf(element: String, threshold: Float): Int {
+		forEachIndexed { i, t ->
+			if (t.almostEquals(element, threshold)) {
+				return i
+			}
+		}
+		return -1
+	}
 
 	companion object {
 
 		private const val TAG = "suggestions"
 		private const val TAG_ONESHOT = "suggestions_oneshot"
-		private const val LIMIT = 140
-		private const val TAGS_LIMIT = 20
-		private const val MAX_PARALLELISM = 4
 		private const val DATA_COUNT = "count"
 		private const val WORKER_CHANNEL_ID = "suggestion_worker"
+		private const val MANGA_CHANNEL_ID = "suggestions"
 		private const val WORKER_NOTIFICATION_ID = 36
+		private const val MAX_RESULTS = 80
+		private const val MAX_RAW_RESULTS = 200
+		private const val TAG_EQ_THRESHOLD = 0.4f
+
+		private val preferredSortOrders = listOf(
+			SortOrder.UPDATED,
+			SortOrder.NEWEST,
+			SortOrder.POPULARITY,
+			SortOrder.RATING,
+		)
 
 		fun setup(context: Context) {
 			val constraints = Constraints.Builder()

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

@@ -1,5 +1,6 @@
 package org.koitharu.kotatsu.utils.ext
 
+import androidx.collection.ArrayMap
 import androidx.collection.ArraySet
 import java.util.Collections
 
@@ -45,3 +46,17 @@ inline fun <T> Collection<T>.filterToSet(predicate: (T) -> Boolean): Set<T> {
 fun <T> Sequence<T>.toListSorted(comparator: Comparator<T>): List<T> {
 	return toMutableList().apply { sortWith(comparator) }
 }
+
+fun <T> List<T>.takeMostFrequent(limit: Int): List<T> {
+	val map = ArrayMap<T, Int>(size)
+	for (item in this) {
+		map[item] = map.getOrDefault(item, 0) + 1
+	}
+	val entries = map.entries.sortedByDescending { it.value }
+	val count = minOf(limit, entries.size)
+	return buildList(count) {
+		repeat(count) { i ->
+			add(entries[i].key)
+		}
+	}
+}

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

@@ -4,6 +4,7 @@ import android.os.SystemClock
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onCompletion
 import kotlinx.coroutines.flow.onEach
@@ -43,3 +44,11 @@ fun <T> Flow<T>.throttle(timeoutMillis: (T) -> Long): Flow<T> {
 fun <T> StateFlow<T?>.requireValue(): T = checkNotNull(value) {
 	"StateFlow value is null"
 }
+
+fun <T> Flow<Collection<T>>.flatten(): Flow<T> = flow {
+	collect { value ->
+		for (item in value) {
+			emit(item)
+		}
+	}
+}

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

@@ -1,5 +1,7 @@
 package org.koitharu.kotatsu.utils.ext
 
+import androidx.annotation.FloatRange
+import org.koitharu.kotatsu.parsers.util.levenshteinDistance
 import java.util.UUID
 
 inline fun String?.ifNullOrEmpty(defaultValue: () -> String): String {
@@ -21,3 +23,14 @@ fun String.toUUIDOrNull(): UUID? = try {
 	e.printStackTraceDebug()
 	null
 }
+
+/**
+ * @param threshold 0 = exact match
+ */
+fun String.almostEquals(other: String, @FloatRange(from = 0.0) threshold: Float): Boolean {
+	if (threshold == 0f) {
+		return equals(other, ignoreCase = true)
+	}
+	val diff = lowercase().levenshteinDistance(other.lowercase()) / ((length + other.length) / 2f)
+	return diff < threshold
+}

app/src/main/res/drawable-anydpi-v24/ic_stat_suggestion.xml

@@ -0,0 +1,17 @@
+<vector
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	android:width="24dp"
+	android:height="24dp"
+	android:tint="#FFFFFF"
+	android:viewportWidth="24"
+	android:viewportHeight="24">
+	<group
+		android:scaleX="1.0036364"
+		android:scaleY="1.0036364"
+		android:translateX="-0.043636363"
+		android:translateY="-0.043636363">
+		<path
+			android:fillColor="#FF000000"
+			android:pathData="M8.6,1.535L6.711,4.715L3.1,5.525L3.439,9.207L1,11.994L3.439,14.773L3.1,18.465L6.711,19.283L8.6,22.465L12,20.994L15.4,22.457L17.289,19.273L20.9,18.457L20.561,14.773L23,11.994L20.561,9.217L20.9,5.535L17.289,4.715L15.4,1.535L12,2.996L8.6,1.535zM10.068,8.521L13.932,8.521C14.357,8.521 14.705,8.866 14.705,9.295L14.705,15.479L12,14.318L9.295,15.479L9.295,9.295A0.773,0.773 0,0 1,10.068 8.521z" />
+	</group>
+</vector>

app/src/main/res/values/strings.xml

@@ -448,6 +448,9 @@
 	<string name="cancel_all">Cancel all</string>
 	<string name="downloads_wifi_only">Download only via Wi-Fi</string>
 	<string name="downloads_wifi_only_summary">Stop downloading when switching to a mobile network</string>
+	<string name="suggestion_manga">Suggestion: %s</string>
+	<string name="suggestions_notifications_summary">Sometimes show notifications with suggested manga</string>
+	<string name="more">More</string>
 	<string name="enable">Enable</string>
 	<string name="no_thanks">No thanks</string>
 	<string name="cancel_all_downloads_confirm">All active downloads will be cancelled, partially downloaded data will be lost</string>
@@ -457,4 +460,5 @@
 	<string name="downloads_paused">Downloads have been paused</string>
 	<string name="downloads_removed">Downloads have been removed</string>
 	<string name="downloads_cancelled">Downloads have been cancelled</string>
+	<string name="suggestions_enable_prompt">Do you want to receive personalized manga suggestions?</string>
 </resources>

app/src/main/res/xml/pref_suggestions.xml

@@ -9,13 +9,22 @@
 		android:layout="@layout/preference_toggle_header"
 		android:title="@string/suggestions_enable" />
 
+	<SwitchPreferenceCompat
+		android:defaultValue="true"
+		android:dependency="suggestions"
+		android:key="suggestions_notifications"
+		android:summary="@string/suggestions_notifications_summary"
+		android:title="@string/notifications_enable" />
+
 	<org.koitharu.kotatsu.settings.utils.MultiAutoCompleteTextViewPreference
 		android:dependency="suggestions"
 		android:key="suggestions_exclude_tags"
 		android:summary="@string/suggestions_excluded_genres_summary"
-		android:title="@string/suggestions_excluded_genres" />
+		android:title="@string/suggestions_excluded_genres"
+		app:allowDividerAbove="true" />
 
 	<SwitchPreferenceCompat
+		android:defaultValue="false"
 		android:dependency="suggestions"
 		android:key="suggestions_exclude_nsfw"
 		android:title="@string/exclude_nsfw_from_suggestions" />
@@ -28,4 +37,4 @@
 		android:summary="@string/suggestions_info"
 		app:allowDividerAbove="true" />
 
-</PreferenceScreen>
+</PreferenceScreen>