Allow creating backups without library entries

- In case you want a backup of just settings?
- Also disable backup options if dependent option is disabled (and fix being able to toggle disabled items)
- Also fix crash in RestoreBackupScreen due to attempt to parcelize Uri
- Make restore validation message a bit nicer

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

@@ -3,9 +3,7 @@ package eu.kanade.tachiyomi.data.backup
 import android.content.Context
 import android.net.Uri
 import eu.kanade.tachiyomi.data.track.TrackerManager
-import tachiyomi.core.i18n.stringResource
 import tachiyomi.domain.source.service.SourceManager
-import tachiyomi.i18n.MR
 import uy.kohesive.injekt.Injekt
 import uy.kohesive.injekt.api.get
 
@@ -19,7 +17,6 @@ class BackupFileValidator(
     /**
      * Checks for critical backup file data.
      *
-     * @throws Exception if manga cannot be found.
      * @return List of missing sources or missing trackers.
      */
     fun validate(uri: Uri): Results {
@@ -29,10 +26,6 @@ class BackupFileValidator(
             throw IllegalStateException(e)
         }
 
-        if (backup.backupManga.isEmpty()) {
-            throw IllegalStateException(context.stringResource(MR.strings.invalid_backup_file_missing_manga))
-        }
-
         val sources = backup.backupSources.associate { it.sourceId to it.name }
         val missingSources = sources
             .filter { sourceManager.get(it.key) == null }

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

@@ -17,25 +17,34 @@ data class BackupOptions(
 
     companion object {
         val libraryOptions = persistentListOf(
+            Entry(
+                label = MR.strings.manga,
+                getter = BackupOptions::libraryEntries,
+                setter = { options, enabled -> options.copy(libraryEntries = enabled) },
+            ),
             Entry(
                 label = MR.strings.categories,
                 getter = BackupOptions::categories,
                 setter = { options, enabled -> options.copy(categories = enabled) },
+                enabled = { it.libraryEntries },
             ),
             Entry(
                 label = MR.strings.chapters,
                 getter = BackupOptions::chapters,
                 setter = { options, enabled -> options.copy(chapters = enabled) },
+                enabled = { it.libraryEntries },
             ),
             Entry(
                 label = MR.strings.track,
                 getter = BackupOptions::tracking,
                 setter = { options, enabled -> options.copy(tracking = enabled) },
+                enabled = { it.libraryEntries },
             ),
             Entry(
                 label = MR.strings.history,
                 getter = BackupOptions::history,
                 setter = { options, enabled -> options.copy(history = enabled) },
+                enabled = { it.libraryEntries },
             ),
         )
 
@@ -54,6 +63,7 @@ data class BackupOptions(
                 label = MR.strings.private_settings,
                 getter = BackupOptions::privateSettings,
                 setter = { options, enabled -> options.copy(privateSettings = enabled) },
+                enabled = { it.appSettings || it.sourceSettings },
             ),
         )
     }
@@ -62,5 +72,6 @@ data class BackupOptions(
         val label: StringResource,
         val getter: (BackupOptions) -> Boolean,
         val setter: (BackupOptions, Boolean) -> BackupOptions,
+        val enabled: (BackupOptions) -> Boolean = { true },
     )
 }

app/src/main/java/eu/kanade/tachiyomi/data/backup/restore/RestoreOptions.kt

@@ -10,8 +10,6 @@ data class RestoreOptions(
     val sourceSettings: Boolean = true,
 ) {
 
-    fun anyEnabled() = library || appSettings || sourceSettings
-
     companion object {
         val options = persistentListOf(
             Entry(