Add option to skip downloading duplicate read chapters (#1125)

* Add query to get chapter count by manga and chapter number

* Add functions to get chapter count by manga and chapter number

* Only count read chapters

* Add interactor

* Savepoint

* Extract new chapter logic to separate function

* Update javadocs

* Add preference to toggle new functionality

* Add todo

* Add debug logcat

* Use string resource instead of hardcoding title

* Add temporary logcat for debugging

* Fix detekt issues

* Update javadocs

* Update download unread chapters preference

* Remove debug logcat calls

* Update javadocs

* Resolve issue where read chapters were still being downloaded during manual manga fetch

* Apply code review changes

* Apply code review changes

* Revert "Apply code review changes"

This reverts commit 1a2dce78acc66a7c529ce5b572bdaf94804b1a30.

* Revert "Apply code review changes"

This reverts commit ac2a77829313967ad39ce3cb0c0231083b9d640d.

* Group download chapter logic inside the interactor GetChaptersToDownload

* Update javadocs

* Apply code review

* Apply code review

* Apply code review

* Update CHANGELOG.md to include the new feature

* Run spotless

* Update domain/src/main/java/mihon/domain/chapter/interactor/FilterChaptersForDownload.kt

---------

Co-authored-by: AntsyLich <59261191+AntsyLich@users.noreply.github.com>

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Copy Tracker URL option to tracker sheet ([@mm12](https://github.com/mm12)) ([#1101](https://github.com/mihonapp/mihon/pull/1101))
 - A button to exclude all scanlators in exclude scanlators dialog ([@AntsyLich](https://github.com/AntsyLich)) ([`84b2164`](https://github.com/mihonapp/mihon/commit/84b2164787a795f3fd757c325cbfb6ef660ac3a3))
 - Open in browser option to reader menu ([@mm12](https://github.com/mm12)) ([#1110](https://github.com/mihonapp/mihon/pull/1110))
+- Option to skip downloading duplicate read chapters ([@shabnix](https://github.com/shabnix)) ([#1125](https://github.com/mihonapp/mihon/pull/1125))
 
 ### Changed
 - Read archive files from memory instead of extracting files to internal storage ([@FooIbar](https://github.com/FooIbar)) ([#326](https://github.com/mihonapp/mihon/pull/326))

app/src/main/java/eu/kanade/domain/DomainModule.kt

@@ -24,6 +24,7 @@ import eu.kanade.domain.track.interactor.RefreshTracks
 import eu.kanade.domain.track.interactor.SyncChapterProgressWithTrack
 import eu.kanade.domain.track.interactor.TrackChapter
 import mihon.data.repository.ExtensionRepoRepositoryImpl
+import mihon.domain.chapter.interactor.FilterChaptersForDownload
 import mihon.domain.extensionrepo.interactor.CreateExtensionRepo
 import mihon.domain.extensionrepo.interactor.DeleteExtensionRepo
 import mihon.domain.extensionrepo.interactor.GetExtensionRepo
@@ -152,6 +153,7 @@ class DomainModule : InjektModule {
         addFactory { ShouldUpdateDbChapter() }
         addFactory { SyncChaptersWithSource(get(), get(), get(), get(), get(), get(), get(), get()) }
         addFactory { GetAvailableScanlators(get()) }
+        addFactory { FilterChaptersForDownload(get(), get(), get()) }
 
         addSingletonFactory<HistoryRepository> { HistoryRepositoryImpl(get()) }
         addFactory { GetHistory(get()) }

app/src/main/java/eu/kanade/presentation/more/settings/screen/SettingsDownloadScreen.kt

@@ -120,6 +120,7 @@ object SettingsDownloadScreen : SearchableSettings {
         allCategories: List<Category>,
     ): Preference.PreferenceGroup {
         val downloadNewChaptersPref = downloadPreferences.downloadNewChapters()
+        val downloadNewUnreadChaptersOnlyPref = downloadPreferences.downloadNewUnreadChaptersOnly()
         val downloadNewChapterCategoriesPref = downloadPreferences.downloadNewChapterCategories()
         val downloadNewChapterCategoriesExcludePref = downloadPreferences.downloadNewChapterCategoriesExclude()
 
@@ -152,6 +153,11 @@ object SettingsDownloadScreen : SearchableSettings {
                     pref = downloadNewChaptersPref,
                     title = stringResource(MR.strings.pref_download_new),
                 ),
+                Preference.PreferenceItem.SwitchPreference(
+                    pref = downloadNewUnreadChaptersOnlyPref,
+                    title = stringResource(MR.strings.pref_download_new_unread_chapters_only),
+                    enabled = downloadNewChapters,
+                ),
                 Preference.PreferenceItem.TextPreference(
                     title = stringResource(MR.strings.categories),
                     subtitle = getCategoriesLabel(

app/src/main/java/eu/kanade/tachiyomi/data/library/LibraryUpdateJob.kt

@@ -24,7 +24,6 @@ import eu.kanade.tachiyomi.data.download.DownloadManager
 import eu.kanade.tachiyomi.data.notification.Notifications
 import eu.kanade.tachiyomi.source.model.SManga
 import eu.kanade.tachiyomi.source.model.UpdateStrategy
-import eu.kanade.tachiyomi.util.shouldDownloadNewChapters
 import eu.kanade.tachiyomi.util.storage.getUriCompat
 import eu.kanade.tachiyomi.util.system.createFileInCacheDir
 import eu.kanade.tachiyomi.util.system.isConnectedToWifi
@@ -39,15 +38,14 @@ import kotlinx.coroutines.ensureActive
 import kotlinx.coroutines.sync.Semaphore
 import kotlinx.coroutines.sync.withPermit
 import logcat.LogPriority
+import mihon.domain.chapter.interactor.FilterChaptersForDownload
 import tachiyomi.core.common.i18n.stringResource
 import tachiyomi.core.common.preference.getAndSet
 import tachiyomi.core.common.util.lang.withIOContext
 import tachiyomi.core.common.util.system.logcat
-import tachiyomi.domain.category.interactor.GetCategories
 import tachiyomi.domain.category.model.Category
 import tachiyomi.domain.chapter.model.Chapter
 import tachiyomi.domain.chapter.model.NoChaptersException
-import tachiyomi.domain.download.service.DownloadPreferences
 import tachiyomi.domain.library.model.LibraryManga
 import tachiyomi.domain.library.service.LibraryPreferences
 import tachiyomi.domain.library.service.LibraryPreferences.Companion.DEVICE_CHARGING
@@ -78,16 +76,15 @@ class LibraryUpdateJob(private val context: Context, workerParams: WorkerParamet
     CoroutineWorker(context, workerParams) {
 
     private val sourceManager: SourceManager = Injekt.get()
-    private val downloadPreferences: DownloadPreferences = Injekt.get()
     private val libraryPreferences: LibraryPreferences = Injekt.get()
     private val downloadManager: DownloadManager = Injekt.get()
     private val coverCache: CoverCache = Injekt.get()
     private val getLibraryManga: GetLibraryManga = Injekt.get()
     private val getManga: GetManga = Injekt.get()
     private val updateManga: UpdateManga = Injekt.get()
-    private val getCategories: GetCategories = Injekt.get()
     private val syncChaptersWithSource: SyncChaptersWithSource = Injekt.get()
     private val fetchInterval: FetchInterval = Injekt.get()
+    private val filterChaptersForDownload: FilterChaptersForDownload = Injekt.get()
 
     private val notifier = LibraryUpdateNotifier(context)
 
@@ -270,9 +267,10 @@ class LibraryUpdateJob(private val context: Context, workerParams: WorkerParamet
                                             .sortedByDescending { it.sourceOrder }
 
                                         if (newChapters.isNotEmpty()) {
-                                            val categoryIds = getCategories.await(manga.id).map { it.id }
-                                            if (manga.shouldDownloadNewChapters(categoryIds, downloadPreferences)) {
-                                                downloadChapters(manga, newChapters)
+                                            val chaptersToDownload = filterChaptersForDownload.await(manga, newChapters)
+
+                                            if (chaptersToDownload.isNotEmpty()) {
+                                                downloadChapters(manga, chaptersToDownload)
                                                 hasDownloads.set(true)
                                             }
 

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaScreenModel.kt

@@ -34,7 +34,6 @@ import eu.kanade.tachiyomi.source.Source
 import eu.kanade.tachiyomi.ui.reader.setting.ReaderPreferences
 import eu.kanade.tachiyomi.util.chapter.getNextUnread
 import eu.kanade.tachiyomi.util.removeCovers
-import eu.kanade.tachiyomi.util.shouldDownloadNewChapters
 import kotlinx.collections.immutable.ImmutableList
 import kotlinx.collections.immutable.toImmutableList
 import kotlinx.coroutines.async
@@ -48,6 +47,7 @@ import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
 import logcat.LogPriority
+import mihon.domain.chapter.interactor.FilterChaptersForDownload
 import tachiyomi.core.common.i18n.stringResource
 import tachiyomi.core.common.preference.CheckboxState
 import tachiyomi.core.common.preference.TriState
@@ -67,7 +67,6 @@ import tachiyomi.domain.chapter.model.ChapterUpdate
 import tachiyomi.domain.chapter.model.NoChaptersException
 import tachiyomi.domain.chapter.service.calculateChapterGap
 import tachiyomi.domain.chapter.service.getChapterSort
-import tachiyomi.domain.download.service.DownloadPreferences
 import tachiyomi.domain.library.service.LibraryPreferences
 import tachiyomi.domain.manga.interactor.GetDuplicateLibraryManga
 import tachiyomi.domain.manga.interactor.GetMangaWithChapters
@@ -87,7 +86,6 @@ class MangaScreenModel(
     val context: Context,
     val mangaId: Long,
     private val isFromSource: Boolean,
-    private val downloadPreferences: DownloadPreferences = Injekt.get(),
     private val libraryPreferences: LibraryPreferences = Injekt.get(),
     readerPreferences: ReaderPreferences = Injekt.get(),
     private val trackerManager: TrackerManager = Injekt.get(),
@@ -109,6 +107,7 @@ class MangaScreenModel(
     private val addTracks: AddTracks = Injekt.get(),
     private val setMangaCategories: SetMangaCategories = Injekt.get(),
     private val mangaRepository: MangaRepository = Injekt.get(),
+    private val filterChaptersForDownload: FilterChaptersForDownload = Injekt.get(),
     val snackbarHostState: SnackbarHostState = SnackbarHostState(),
 ) : StateScreenModel<MangaScreenModel.State>(State.Loading) {
 
@@ -771,15 +770,11 @@ class MangaScreenModel(
     private fun downloadNewChapters(chapters: List<Chapter>) {
         screenModelScope.launchNonCancellable {
             val manga = successState?.manga ?: return@launchNonCancellable
-            val categories = getCategories.await(manga.id).map { it.id }
-            if (
-                chapters.isEmpty() ||
-                !manga.shouldDownloadNewChapters(categories, downloadPreferences)
-            ) {
-                return@launchNonCancellable
-            }
+            val chaptersToDownload = filterChaptersForDownload.await(manga, chapters)
 
-            downloadChapters(chapters)
+            if (chaptersToDownload.isNotEmpty()) {
+                downloadChapters(chaptersToDownload)
+            }
         }
     }
 

app/src/main/java/eu/kanade/tachiyomi/util/MangaExtensions.kt

@@ -5,7 +5,6 @@ import eu.kanade.domain.manga.model.hasCustomCover
 import eu.kanade.domain.manga.model.toSManga
 import eu.kanade.tachiyomi.data.cache.CoverCache
 import eu.kanade.tachiyomi.source.model.SManga
-import tachiyomi.domain.download.service.DownloadPreferences
 import tachiyomi.domain.manga.model.Manga
 import tachiyomi.source.local.image.LocalCoverManager
 import tachiyomi.source.local.isLocal
@@ -50,31 +49,6 @@ fun Manga.removeCovers(coverCache: CoverCache = Injekt.get()): Manga {
     }
 }
 
-fun Manga.shouldDownloadNewChapters(dbCategories: List<Long>, preferences: DownloadPreferences): Boolean {
-    if (!favorite) return false
-
-    val categories = dbCategories.ifEmpty { listOf(0L) }
-
-    // Boolean to determine if user wants to automatically download new chapters.
-    val downloadNewChapters = preferences.downloadNewChapters().get()
-    if (!downloadNewChapters) return false
-
-    val includedCategories = preferences.downloadNewChapterCategories().get().map { it.toLong() }
-    val excludedCategories = preferences.downloadNewChapterCategoriesExclude().get().map { it.toLong() }
-
-    // Default: Download from all categories
-    if (includedCategories.isEmpty() && excludedCategories.isEmpty()) return true
-
-    // In excluded category
-    if (categories.any { it in excludedCategories }) return false
-
-    // Included category not selected
-    if (includedCategories.isEmpty()) return true
-
-    // In included category
-    return categories.any { it in includedCategories }
-}
-
 suspend fun Manga.editCover(
     coverManager: LocalCoverManager,
     stream: InputStream,

domain/src/main/java/mihon/domain/chapter/interactor/FilterChaptersForDownload.kt

@@ -0,0 +1,77 @@
+package mihon.domain.chapter.interactor
+
+import tachiyomi.domain.category.interactor.GetCategories
+import tachiyomi.domain.chapter.interactor.GetChaptersByMangaId
+import tachiyomi.domain.chapter.model.Chapter
+import tachiyomi.domain.download.service.DownloadPreferences
+import tachiyomi.domain.manga.model.Manga
+
+/**
+ * Interactor responsible for determining which chapters of a manga should be downloaded.
+ *
+ * @property getChaptersByMangaId Interactor for retrieving chapters by manga ID.
+ * @property downloadPreferences User preferences related to chapter downloads.
+ * @property getCategories Interactor for retrieving categories associated with a manga.
+ */
+class FilterChaptersForDownload(
+    private val getChaptersByMangaId: GetChaptersByMangaId,
+    private val downloadPreferences: DownloadPreferences,
+    private val getCategories: GetCategories,
+) {
+
+    /**
+     * Determines which chapters of a manga should be downloaded based on user preferences.
+     *
+     * @param manga The manga for which chapters may be downloaded.
+     * @param newChapters The list of new chapters available for the manga.
+     * @return A list of chapters that should be downloaded
+     */
+    suspend fun await(manga: Manga, newChapters: List<Chapter>): List<Chapter> {
+        if (
+            newChapters.isEmpty() ||
+            !downloadPreferences.downloadNewChapters().get() ||
+            !manga.shouldDownloadNewChapters()
+        ) {
+            return emptyList()
+        }
+
+        if (!downloadPreferences.downloadNewUnreadChaptersOnly().get()) return newChapters
+
+        val readChapterNumbers = getChaptersByMangaId.await(manga.id)
+            .asSequence()
+            .filter { it.read && it.isRecognizedNumber }
+            .map { it.chapterNumber }
+            .toSet()
+
+        return newChapters.filterNot { it.chapterNumber in readChapterNumbers }
+    }
+
+    /**
+     * Determines whether new chapters should be downloaded for the manga based on user preferences and the
+     * categories to which the manga belongs.
+     *
+     * @return `true` if chapters of the manga should be downloaded
+     */
+    private suspend fun Manga.shouldDownloadNewChapters(): Boolean {
+        if (!favorite) return false
+
+        val categories = getCategories.await(id).map { it.id }.ifEmpty { listOf(DEFAULT_CATEGORY_ID) }
+        val includedCategories = downloadPreferences.downloadNewChapterCategories().get().map { it.toLong() }
+        val excludedCategories = downloadPreferences.downloadNewChapterCategoriesExclude().get().map { it.toLong() }
+
+        return when {
+            // Default Download from all categories
+            includedCategories.isEmpty() && excludedCategories.isEmpty() -> true
+            // In excluded category
+            categories.any { it in excludedCategories } -> false
+            // Included category not selected
+            includedCategories.isEmpty() -> true
+            // In included category
+            else -> categories.any { it in includedCategories }
+        }
+    }
+
+    companion object {
+        private const val DEFAULT_CATEGORY_ID = 0L
+    }
+}

domain/src/main/java/tachiyomi/domain/download/service/DownloadPreferences.kt

@@ -42,4 +42,6 @@ class DownloadPreferences(
         "download_new_categories_exclude",
         emptySet(),
     )
+
+    fun downloadNewUnreadChaptersOnly() = preferenceStore.getBoolean("download_new_unread_chapters_only", false)
 }

i18n/src/commonMain/moko-resources/base/strings.xml

@@ -484,6 +484,7 @@
     <string name="fifth_to_last">Fifth to last read chapter</string>
     <string name="pref_category_auto_download">Auto-download</string>
     <string name="pref_download_new">Download new chapters</string>
+    <string name="pref_download_new_unread_chapters_only">Skip downloading duplicate read chapters</string>
     <string name="pref_download_new_categories_details">Entries in excluded categories will not be downloaded even if they are also in included categories.</string>
     <string name="download_ahead">Download ahead</string>
     <string name="auto_download_while_reading">Auto download while reading</string>