feat: Add saved filters to backup and restore

This commit adds support for backing up and restoring saved filters.

- Added a new `SAVED_FILTERS` section to the backup process.
- Implemented the logic to read filters from SharedPreferences during backup and write them back during restore.

app/src/main/kotlin/org/koitharu/kotatsu/backups/data/BackupRepository.kt

@@ -26,6 +26,7 @@ import org.koitharu.kotatsu.backups.data.model.CategoryBackup
 import org.koitharu.kotatsu.backups.data.model.FavouriteBackup
 import org.koitharu.kotatsu.backups.data.model.HistoryBackup
 import org.koitharu.kotatsu.backups.data.model.MangaBackup
+import org.koitharu.kotatsu.backups.data.model.SavedFilterBackup
 import org.koitharu.kotatsu.backups.data.model.ScrobblingBackup
 import org.koitharu.kotatsu.backups.data.model.SourceBackup
 import org.koitharu.kotatsu.backups.data.model.StatisticBackup
@@ -34,6 +35,8 @@ import org.koitharu.kotatsu.core.db.MangaDatabase
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.util.CompositeResult
 import org.koitharu.kotatsu.core.util.progress.Progress
+import org.koitharu.kotatsu.explore.data.MangaSourcesRepository
+import org.koitharu.kotatsu.filter.data.SavedFiltersRepository
 import org.koitharu.kotatsu.parsers.util.runCatchingCancellable
 import org.koitharu.kotatsu.reader.data.TapGridSettings
 import java.io.InputStream
@@ -48,6 +51,8 @@ class BackupRepository @Inject constructor(
 	private val database: MangaDatabase,
 	private val settings: AppSettings,
 	private val tapGridSettings: TapGridSettings,
+	private val mangaSourcesRepository: MangaSourcesRepository,
+	private val savedFiltersRepository: SavedFiltersRepository,
 ) {
 
 	private val json = Json {
@@ -123,6 +128,18 @@ class BackupRepository @Inject constructor(
 					data = database.getStatsDao().dumpEnabled().map { StatisticBackup(it) },
 					serializer = serializer(),
 				)
+
+				BackupSection.SAVED_FILTERS -> {
+					val sources = mangaSourcesRepository.getEnabledSources()
+					val filters = sources.flatMap { source ->
+						savedFiltersRepository.getAll(source)
+					}
+					output.writeJsonArray(
+						section = BackupSection.SAVED_FILTERS,
+						data = filters.asFlow().map { SavedFilterBackup(it) },
+						serializer = serializer(),
+					)
+				}
 			}
 			progress?.emit(commonProgress)
 			commonProgress++
@@ -185,6 +202,15 @@ class BackupRepository @Inject constructor(
 						getStatsDao().upsert(it.toEntity())
 					}
 
+					BackupSection.SAVED_FILTERS -> input.readJsonArray<SavedFilterBackup>(serializer())
+						.restoreWithoutTransaction {
+							savedFiltersRepository.save(
+								source = it.source,
+								name = it.name,
+								filter = it.filter,
+							)
+						}
+
 					null -> CompositeResult.EMPTY // skip unknown entries
 				}
 				progress?.emit(commonProgress)
@@ -281,4 +307,12 @@ class BackupRepository @Inject constructor(
 			}
 		}
 	}
+
+	private suspend inline fun <T> Sequence<T>.restoreWithoutTransaction(crossinline block: suspend (T) -> Unit): CompositeResult {
+		return fold(CompositeResult.EMPTY) { result, item ->
+			result + runCatchingCancellable {
+				block(item)
+			}
+		}
+	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/backups/data/model/SavedFilterBackup.kt

@@ -0,0 +1,34 @@
+package org.koitharu.kotatsu.backups.data.model
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import org.koitharu.kotatsu.core.model.MangaSourceSerializer
+import org.koitharu.kotatsu.filter.data.MangaListFilterSerializer
+import org.koitharu.kotatsu.filter.data.PersistableFilter
+import org.koitharu.kotatsu.parsers.model.MangaListFilter
+import org.koitharu.kotatsu.parsers.model.MangaSource
+
+@Serializable
+data class SavedFilterBackup(
+    @SerialName("name")
+    val name: String,
+    @Serializable(with = MangaSourceSerializer::class)
+    @SerialName("source")
+    val source: MangaSource,
+    @Serializable(with = MangaListFilterSerializer::class)
+    @SerialName("filter")
+    val filter: MangaListFilter,
+) {
+
+    constructor(persistableFilter: PersistableFilter) : this(
+        name = persistableFilter.name,
+        source = persistableFilter.source,
+        filter = persistableFilter.filter,
+    )
+
+    fun toPersistableFilter() = PersistableFilter(
+        name = name,
+        source = source,
+        filter = filter,
+    )
+}

app/src/main/kotlin/org/koitharu/kotatsu/backups/domain/BackupSection.kt

@@ -17,6 +17,7 @@ enum class BackupSection(
 	SOURCES("sources"),
 	SCROBBLING("scrobbling"),
 	STATS("statistics"),
+	SAVED_FILTERS("saved_filters"),
 	;
 
 	companion object {