Use a single preference to store migration flags

app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt

@@ -165,10 +165,6 @@ class PreferencesHelper(val context: Context) {
 
     fun defaultCategory() = prefs.getInt(Keys.defaultCategory, -1)
 
-    fun migrateChapters() = rxPrefs.getBoolean("migrate_chapters", true)
-
-    fun migrateTracks() = rxPrefs.getBoolean("migrate_tracks", true)
-
-    fun migrateCategories() = rxPrefs.getBoolean("migrate_categories", true)
+    fun migrateFlags() = rxPrefs.getInteger("migrate_flags", Int.MAX_VALUE)
 
 }

app/src/main/java/eu/kanade/tachiyomi/ui/migration/MigrationFlags.kt

@@ -0,0 +1,38 @@
+package eu.kanade.tachiyomi.ui.migration
+
+import eu.kanade.tachiyomi.R
+
+object MigrationFlags {
+
+    private const val CHAPTERS   = 0b001
+    private const val CATEGORIES = 0b010
+    private const val TRACK      = 0b100
+
+    private const val CHAPTERS2   = 0x1
+    private const val CATEGORIES2 = 0x2
+    private const val TRACK2      = 0x4
+
+    val titles get() = arrayOf(R.string.chapters, R.string.categories, R.string.track)
+
+    val flags get() = arrayOf(CHAPTERS, CATEGORIES, TRACK)
+
+    fun hasChapters(value: Int): Boolean {
+        return value and CHAPTERS != 0
+    }
+
+    fun hasCategories(value: Int): Boolean {
+        return value and CATEGORIES != 0
+    }
+
+    fun hasTracks(value: Int): Boolean {
+        return value and TRACK != 0
+    }
+
+    fun getEnabledFlagsPositions(value: Int): List<Int> {
+        return flags.mapIndexedNotNull { index, flag -> if (value and flag != 0) index else null }
+    }
+
+    fun getFlagsFromPositions(positions: Array<Int>): Int {
+        return positions.fold(0, { accumulated, position -> accumulated or (1 shl position) })
+    }
+}

app/src/main/java/eu/kanade/tachiyomi/ui/migration/MigrationPresenter.kt

@@ -97,9 +97,14 @@ class MigrationPresenter(
     private fun migrateMangaInternal(source: Source, sourceChapters: List<SChapter>,
                                      prevManga: Manga, manga: Manga, replace: Boolean) {
 
+        val flags = preferences.migrateFlags().getOrDefault()
+        val migrateChapters = MigrationFlags.hasChapters(flags)
+        val migrateCategories = MigrationFlags.hasCategories(flags)
+        val migrateTracks = MigrationFlags.hasTracks(flags)
+
         db.inTransaction {
             // Update chapters read
-            if (preferences.migrateChapters().getOrDefault()) {
+            if (migrateChapters) {
                 try {
                     syncChaptersWithSource(db, sourceChapters, manga, source)
                 } catch (e: Exception) {
@@ -120,13 +125,13 @@ class MigrationPresenter(
                 }
             }
             // Update categories
-            if (preferences.migrateCategories().getOrDefault()) {
+            if (migrateCategories) {
                 val categories = db.getCategoriesForManga(prevManga).executeAsBlocking()
                 val mangaCategories = categories.map { MangaCategory.create(manga, it) }
                 db.setMangaCategories(mangaCategories, listOf(manga))
             }
             // Update track
-            if (preferences.migrateTracks().getOrDefault()) {
+            if (migrateTracks) {
                 val tracks = db.getTracks(prevManga).executeAsBlocking()
                 for (track in tracks) {
                     track.id = null

app/src/main/java/eu/kanade/tachiyomi/ui/migration/SearchController.kt

@@ -64,31 +64,19 @@ class SearchController(
         private val preferences: PreferencesHelper by injectLazy()
 
         override fun onCreateDialog(savedViewState: Bundle?): Dialog {
-            val optionTitles = arrayOf(
-                    R.string.chapters,
-                    R.string.categories,
-                    R.string.track
-            )
-
-            val optionPrefs = arrayOf(
-                    preferences.migrateChapters(),
-                    preferences.migrateCategories(),
-                    preferences.migrateTracks()
-            )
-
-            val preselected = optionPrefs.mapIndexedNotNull { index, preference ->
-                if (preference.getOrDefault()) index else null
-            }
+            val prefValue = preferences.migrateFlags().getOrDefault()
+
+            val preselected = MigrationFlags.getEnabledFlagsPositions(prefValue)
 
             return MaterialDialog.Builder(activity!!)
                     .content(R.string.migration_dialog_what_to_include)
-                    .items(optionTitles.map { resources?.getString(it) })
+                    .items(MigrationFlags.titles.map { resources?.getString(it) })
                     .alwaysCallMultiChoiceCallback()
                     .itemsCallbackMultiChoice(preselected.toTypedArray(), { _, positions, _ ->
                         // Save current settings for the next time
-                        optionPrefs.forEachIndexed { index, preference ->
-                            preference.set(index in positions)
-                        }
+                        val newValue = MigrationFlags.getFlagsFromPositions(positions)
+                        preferences.migrateFlags().set(newValue)
+
                         true
                     })
                     .positiveText(R.string.migrate)