Remove the unused mark duplicate as read preference. (#1448)

* Remove the unused mark duplicate as read preference.

* Migrate the old preference to new preference

app/src/main/java/mihon/core/migration/migrations/Migrations.kt

@@ -46,4 +46,5 @@ val migrations: List<Migration>
         MoveEncryptionSettingsToAppStateMigration(),
         TrustExtensionRepositoryMigration(),
         CategoryPreferencesCleanupMigration(),
+        RemoveDuplicateReaderPreferenceMigration(),
     )

app/src/main/java/mihon/core/migration/migrations/RemoveDuplicateReaderPreferenceMigration.kt

@@ -0,0 +1,26 @@
+package mihon.core.migration.migrations
+
+import android.content.SharedPreferences
+import androidx.core.content.edit
+import mihon.core.migration.Migration
+import mihon.core.migration.MigrationContext
+import tachiyomi.core.common.util.lang.withIOContext
+
+class RemoveDuplicateReaderPreferenceMigration : Migration {
+    override val version: Float = 74f
+
+    override suspend fun invoke(migrationContext: MigrationContext): Boolean = withIOContext {
+        val prefs = migrationContext.get<SharedPreferences>() ?: return@withIOContext false
+
+        if (prefs.getBoolean("mark_read_dupe", false)) {
+            val readPrefSet = prefs.getStringSet("mark_duplicate_read_chapter_read", emptySet())?.toMutableSet()
+            readPrefSet?.add("existing")
+            prefs.edit {
+                putStringSet("mark_duplicate_read_chapter_read", readPrefSet)
+                remove("mark_read_dupe")
+            }
+        }
+
+        return@withIOContext true
+    }
+}