Merge manga favorite related fields into favorite_at

Migration 16 replaces favorite, date_added and favorite_modified_at with one nullable favorite_at. A favorite whose date_added is 0 falls back to favorite_modified_at. Manga.favorite and dateAdded become getters derived from it, and restore merges it by taking the earliest non-zero time.

app/src/main/java/eu/kanade/domain/manga/interactor/UpdateManga.kt

@@ -48,15 +48,10 @@ class UpdateManga(
     }
 
     suspend fun awaitUpdateFavorite(mangaId: Long, favorite: Boolean): Boolean {
-        val dateAdded = when (favorite) {
-            true -> Clock.System.now().toEpochMilliseconds()
-            false -> 0
+        val update = when (favorite) {
+            true -> MangaUpdate(mangaId) { favoriteAt = Clock.System.now().toEpochMilliseconds() }
+            false -> MangaUpdate(mangaId) { favoriteAt = null }
         }
-        return mangaRepository.update(
-            MangaUpdate(mangaId) {
-                this.favorite = favorite
-                this.dateAdded = dateAdded
-            },
-        )
+        return mangaRepository.update(update)
     }
 }

app/src/main/java/eu/kanade/tachiyomi/data/backup/create/creators/MangaBackupCreator.kt

@@ -88,12 +88,11 @@ private fun Manga.toBackupManga() =
         thumbnailUrl = this.thumbnailUrl,
         favorite = this.favorite,
         source = this.source,
-        dateAdded = this.dateAdded,
+        dateAdded = this.favoriteAt ?: 0L,
         viewer = (this.viewerFlags.toInt() and ReadingMode.MASK),
         viewer_flags = this.viewerFlags.toInt(),
         chapterFlags = this.chapterFlags.toInt(),
         updateStrategy = this.updateStrategy,
-        favoriteModifiedAt = this.favoriteModifiedAt,
         notes = this.notes,
         initialized = this.initialized,
         memo = this.memo.toByteArray(),

app/src/main/java/eu/kanade/tachiyomi/data/backup/models/BackupManga.kt

@@ -57,13 +57,19 @@ class BackupManga(
             genre = this@BackupManga.genre,
             status = this@BackupManga.status.toLong(),
             thumbnailUrl = this@BackupManga.thumbnailUrl,
-            favorite = this@BackupManga.favorite,
             source = this@BackupManga.source,
-            dateAdded = this@BackupManga.dateAdded,
+            // For libraries older than dateAdded, the favorite timestamp is the only record of when
+            // an entry was added. It was written by a trigger in seconds, unlike dateAdded.
+            favoriteAt = if (this@BackupManga.favorite) {
+                this@BackupManga.dateAdded.takeIf { it != 0L }
+                    ?: this@BackupManga.favoriteModifiedAt?.times(1000)
+                    ?: 0L
+            } else {
+                null
+            },
             viewerFlags = (this@BackupManga.viewer_flags ?: this@BackupManga.viewer).toLong(),
             chapterFlags = this@BackupManga.chapterFlags.toLong(),
             updateStrategy = this@BackupManga.updateStrategy,
-            favoriteModifiedAt = this@BackupManga.favoriteModifiedAt,
             notes = this@BackupManga.notes,
             initialized = this@BackupManga.initialized,
             memo = this@BackupManga.memo.toJsonObject(),

app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/browse/BrowseSourceViewModel.kt

@@ -236,17 +236,13 @@ class BrowseSourceViewModel(
             val update = if (manga.favorite) {
                 val coverLastModified = manga.removeCovers(coverCache).coverLastModified
                 MangaUpdate(manga.id) {
-                    favorite = false
-                    dateAdded = 0
+                    favoriteAt = null
                     if (coverLastModified != manga.coverLastModified) this.coverLastModified = coverLastModified
                 }
             } else {
                 setMangaDefaultChapterFlags.await(manga)
                 addTracks.bindEnhancedTrackers(manga, sourceManager.getOrStub(manga.source))
-                MangaUpdate(manga.id) {
-                    favorite = true
-                    dateAdded = Clock.System.now().toEpochMilliseconds()
-                }
+                MangaUpdate(manga.id) { favoriteAt = Clock.System.now().toEpochMilliseconds() }
             }
 
             updateManga.await(update)

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryViewModel.kt

@@ -338,7 +338,7 @@ class LibraryViewModel(
                     manga1.libraryManga.chapterFetchedAt.compareTo(manga2.libraryManga.chapterFetchedAt)
                 }
                 LibrarySort.Type.DateAdded -> {
-                    manga1.libraryManga.manga.dateAdded.compareTo(manga2.libraryManga.manga.dateAdded)
+                    compareValues(manga1.libraryManga.manga.favoriteAt, manga2.libraryManga.manga.favoriteAt)
                 }
                 LibrarySort.Type.TrackerMean -> {
                     val item1Score = trackerScores[manga1.id] ?: defaultTrackerScoreSortValue
@@ -572,7 +572,7 @@ class LibraryViewModel(
                 val toDelete = mangas.map {
                     it.removeCovers(coverCache)
                     MangaUpdate(it.id) {
-                        favorite = false
+                        favoriteAt = null
                     }
                 }
                 updateManga.awaitAll(toDelete)