diff --git a/src/ui/flutter_app/lib/mill/game.dart b/src/ui/flutter_app/lib/mill/game.dart
index d8b497fb..5d65ec26 100644
--- a/src/ui/flutter_app/lib/mill/game.dart
+++ b/src/ui/flutter_app/lib/mill/game.dart
@@ -32,6 +32,7 @@ class Game {
   final String tag = "[game]";
 
   void init() {
+    // TODO: _position is allready initialized with Position(). seems like duplicate code
     _position = Position();
     focusIndex = blurIndex = invalidIndex;
   }
@@ -71,7 +72,7 @@ class Game {
     PieceColor.black: false
   };
 
-  bool aiIsSearching() {
+  bool get aiIsSearching {
     debugPrint(
       "$tag White is searching? ${isSearching[PieceColor.white]}\n"
       "$tag Black is searching? ${isSearching[PieceColor.black]}\n",
@@ -115,14 +116,14 @@ class Game {
     blurIndex = invalidIndex;
   }
 
-  bool doMove(String move) {
+  Future<bool> doMove(String move) async {
     if (position.phase == Phase.ready) {
       start();
     }
 
     debugPrint("$tag AI do move: $move");
 
-    if (!position.doMove(move)) {
+    if (await position.doMove(move) == false) {
       return false;
     }
 
diff --git a/src/ui/flutter_app/lib/mill/position.dart b/src/ui/flutter_app/lib/mill/position.dart
index a219e540..5e6415c6 100644
--- a/src/ui/flutter_app/lib/mill/position.dart
+++ b/src/ui/flutter_app/lib/mill/position.dart
@@ -25,6 +25,7 @@ import 'package:sanmill/mill/types.dart';
 import 'package:sanmill/mill/zobrist.dart';
 import 'package:sanmill/services/audios.dart';
 import 'package:sanmill/services/engine/engine.dart';
+import 'package:sanmill/shared/common/config.dart';
 
 List<int> posKeyHistory = [];
 
@@ -62,7 +63,7 @@ class Position {
 
   String us = PieceColor.white;
   String them = PieceColor.black;
-  String winner = PieceColor.nobody;
+  String _winner = PieceColor.nobody;
 
   GameOverReason gameOverReason = GameOverReason.noReason;
 
@@ -114,7 +115,7 @@ class Position {
     st.pliesFromNull = other.st.pliesFromNull;
 
     them = other.them;
-    winner = other.winner;
+    _winner = other._winner;
     gameOverReason = other.gameOverReason;
 
     phase = other.phase;
@@ -135,7 +136,7 @@ class Position {
 
   String movedPiece(int move) => pieceOn(fromSq(move));
 
-  bool movePiece(int from, int to) {
+  Future<bool> movePiece(int from, int to) async {
     if (selectPiece(from) == 0) {
       return putPiece(to);
     }
@@ -261,7 +262,7 @@ class Position {
     return true;
   }
 
-  bool doMove(String move) {
+  Future<bool> doMove(String move) async {
     if (move.length > "Player".length &&
         move.substring(0, "Player".length - 1) == "Player") {
       if (move["Player".length] == '1') {
@@ -278,7 +279,7 @@ class Position {
 
     if (move == "draw") {
       phase = Phase.gameOver;
-      winner = PieceColor.draw;
+      _winner = PieceColor.draw;
       if (score[PieceColor.draw] != null) {
         score[PieceColor.draw] = score[PieceColor.draw]! + 1;
       }
@@ -287,7 +288,7 @@ class Position {
       if (rule.nMoveRule > 0 && posKeyHistory.length >= rule.nMoveRule - 1) {
         gameOverReason = GameOverReason.drawReasonRule50;
       } else if (rule.endgameNMoveRule < rule.nMoveRule &&
-          isThreeEndgame() &&
+          isThreeEndgame &&
           posKeyHistory.length >= rule.endgameNMoveRule - 1) {
         gameOverReason = GameOverReason.drawReasonEndgameRule50;
       } else if (rule.threefoldRepetitionRule) {
@@ -308,20 +309,20 @@ class Position {
 
     switch (m.type) {
       case MoveType.remove:
-        ret = removePiece(m.to) == 0;
+        ret = await removePiece(m.to) == 0;
         if (ret) {
           // Reset rule 50 counter
           st.rule50 = 0;
         }
         break;
       case MoveType.move:
-        ret = movePiece(m.from, m.to);
+        ret = await movePiece(m.from, m.to);
         if (ret) {
           ++st.rule50;
         }
         break;
       case MoveType.place:
-        ret = putPiece(m.to);
+        ret = await putPiece(m.to);
         if (ret) {
           // Reset rule 50 counter
           st.rule50 = 0;
@@ -414,7 +415,7 @@ class Position {
     setSideToMove(PieceColor.white);
     action = Act.place;
 
-    winner = PieceColor.nobody;
+    _winner = PieceColor.nobody;
     gameOverReason = GameOverReason.noReason;
 
     clearBoard();
@@ -457,7 +458,7 @@ class Position {
     }
   }
 
-  bool putPiece(int s) {
+  Future<bool> putPiece(int s) async {
     var piece = Piece.noPiece;
     final us = _sideToMove;
 
@@ -472,6 +473,7 @@ class Position {
       start();
     }
 
+    // TODO: use switch case
     if (phase == Phase.placing) {
       piece = sideToMove;
       if (pieceInHandCount[us] != null) {
@@ -501,7 +503,7 @@ class Position {
 
         if (pieceInHandCount[PieceColor.white] == 0 &&
             pieceInHandCount[PieceColor.black] == 0) {
-          if (checkIfGameIsOver()) {
+          if (isGameOver()) {
             return true;
           }
 
@@ -516,14 +518,14 @@ class Position {
             changeSideToMove();
           }
 
-          if (checkIfGameIsOver()) {
+          if (isGameOver()) {
             return true;
           }
         } else {
           changeSideToMove();
         }
         gameInstance.focusIndex = squareToIndex[s] ?? invalidIndex;
-        Audios.playTone(Audios.placeSoundId);
+        await Audios.playTone(Sound.place);
       } else {
         pieceToRemoveCount = rule.mayRemoveMultiple ? n : 1;
         updateKeyMisc();
@@ -539,7 +541,7 @@ class Position {
 
           if (pieceInHandCount[PieceColor.white] == 0 &&
               pieceInHandCount[PieceColor.black] == 0) {
-            if (checkIfGameIsOver()) {
+            if (isGameOver()) {
               return true;
             }
 
@@ -550,7 +552,7 @@ class Position {
               changeSideToMove();
             }
 
-            if (checkIfGameIsOver()) {
+            if (isGameOver()) {
               return true;
             }
           }
@@ -559,10 +561,10 @@ class Position {
         }
 
         gameInstance.focusIndex = squareToIndex[s] ?? invalidIndex;
-        Audios.playTone(Audios.millSoundId);
+        await Audios.playTone(Sound.mill);
       }
     } else if (phase == Phase.moving) {
-      if (checkIfGameIsOver()) {
+      if (isGameOver()) {
         return true;
       }
 
@@ -603,18 +605,18 @@ class Position {
         action = Act.select;
         changeSideToMove();
 
-        if (checkIfGameIsOver()) {
+        if (isGameOver()) {
           return true;
         } else {
           gameInstance.focusIndex = squareToIndex[s] ?? invalidIndex;
-          Audios.playTone(Audios.placeSoundId);
+          await Audios.playTone(Sound.place);
         }
       } else {
         pieceToRemoveCount = rule.mayRemoveMultiple ? n : 1;
         updateKeyMisc();
         action = Act.remove;
         gameInstance.focusIndex = squareToIndex[s] ?? invalidIndex;
-        Audios.playTone(Audios.millSoundId);
+        await Audios.playTone(Sound.mill);
       }
     } else {
       assert(false);
@@ -623,7 +625,7 @@ class Position {
     return true;
   }
 
-  int removePiece(int s) {
+  Future<int> removePiece(int s) async {
     if (phase == Phase.ready || phase == Phase.gameOver) return -1;
 
     if (action != Act.remove) return -1;
@@ -641,7 +643,7 @@ class Position {
 
     revertKey(s);
 
-    Audios.playTone(Audios.removeSoundId);
+    await Audios.playTone(Sound.remove);
 
     if (rule.hasBannedLocations && phase == Phase.placing) {
       // Remove and put ban
@@ -685,7 +687,7 @@ class Position {
         }
 
         if (rule.isDefenderMoveFirst) {
-          checkIfGameIsOver();
+          isGameOver();
           return 0;
         }
       } else {
@@ -696,7 +698,7 @@ class Position {
     }
 
     changeSideToMove();
-    checkIfGameIsOver();
+    isGameOver();
 
     return 0;
   }
@@ -733,14 +735,12 @@ class Position {
     return true;
   }
 
-  String getWinner() {
-    return winner;
-  }
+  String get winner => _winner;
 
   void setGameOver(String w, GameOverReason reason) {
     phase = Phase.gameOver;
     gameOverReason = reason;
-    winner = w;
+    _winner = w;
 
     debugPrint("[position] Game over, $w win, because of $reason");
     updateScore();
@@ -748,7 +748,7 @@ class Position {
 
   void updateScore() {
     if (phase == Phase.gameOver) {
-      if (winner == PieceColor.draw) {
+      if (_winner == PieceColor.draw) {
         if (score[PieceColor.draw] != null) {
           score[PieceColor.draw] = score[PieceColor.draw]! + 1;
         }
@@ -756,13 +756,13 @@ class Position {
         return;
       }
 
-      if (score[winner] != null) {
-        score[winner] = score[winner]! + 1;
+      if (score[_winner] != null) {
+        score[_winner] = score[_winner]! + 1;
       }
     }
   }
 
-  bool isThreeEndgame() {
+  bool get isThreeEndgame {
     if (phase == Phase.placing) {
       return false;
     }
@@ -771,7 +771,7 @@ class Position {
         pieceOnBoardCount[PieceColor.black] == 3;
   }
 
-  bool checkIfGameIsOver() {
+  bool isGameOver() {
     if (phase == Phase.ready || phase == Phase.gameOver) {
       return true;
     }
@@ -782,7 +782,7 @@ class Position {
     }
 
     if (rule.endgameNMoveRule < rule.nMoveRule &&
-        isThreeEndgame() &&
+        isThreeEndgame &&
         posKeyHistory.length >= rule.endgameNMoveRule) {
       setGameOver(PieceColor.draw, GameOverReason.drawReasonEndgameRule50);
       return true;
@@ -1047,7 +1047,7 @@ class Position {
     nPiecesInHand;
     pieceToRemoveCount = 0;
 
-    winner = PieceColor.nobody;
+    _winner = PieceColor.nobody;
     Mills.adjacentSquaresInit();
     Mills.millTableInit();
     currentSquare = 0;
@@ -1086,25 +1086,29 @@ class Position {
   }
 
 ///////////////////////////////////////////////////////////////////////////////
-
-  Future<String> _gotoHistory(int moveIndex) async {
-    String errString = "";
+  Future<String> gotoHistory(HistoryMove move, [int? index]) async {
+    final int moveIndex = _gotoHistoryIndex(move, index);
 
     if (recorder == null) {
       debugPrint("[goto] recorder is null.");
       return "null";
     }
 
+    if (recorder!.cur == moveIndex) {
+      debugPrint("[goto] cur is equal to moveIndex.");
+      return "equal";
+    }
+
     final history = recorder!.history;
+
     if (moveIndex < -1 || history.length <= moveIndex) {
       debugPrint("[goto] moveIndex is out of range.");
       return "out-of-range";
     }
 
-    if (recorder!.cur == moveIndex) {
-      debugPrint("[goto] cur is equal to moveIndex.");
-      return "equal";
-    }
+    String errString = "";
+
+    Audios.isTemporaryMute = true;
 
     // Backup context
     final engineTypeBackup = gameInstance.engineType;
@@ -1121,13 +1125,10 @@ class Position {
     }
 
     for (var i = 0; i <= moveIndex; i++) {
-      if (gameInstance.doMove(history[i].move!) == false) {
+      if (await gameInstance.doMove(history[i].move!) == false) {
         errString = history[i].move!;
         break;
       }
-
-      //await Future.delayed(Duration(seconds: 1));
-      //setState(() {});
     }
 
     // Restore context
@@ -1136,31 +1137,46 @@ class Position {
     recorder!.history = historyBack;
     recorder!.cur = moveIndex;
 
+    Audios.isTemporaryMute = false;
+    await _gotoHistoryPlaySound(move);
+
     return errString;
   }
 
-  Future<String> takeBackN(int n) async {
-    int index = recorder!.cur - n;
-    if (index < -1) {
-      index = -1;
+  int _gotoHistoryIndex(HistoryMove move, [int? index]) {
+    switch (move) {
+      case HistoryMove.forwardAll:
+        return recorder!.history.length - 1;
+      case HistoryMove.backAll:
+        return -1;
+      case HistoryMove.farward:
+        return recorder!.cur + 1;
+      case HistoryMove.backN:
+        assert(index != null);
+        int _index = recorder!.cur - index!;
+        if (_index < -1) {
+          _index = -1;
+        }
+        return _index;
+      case HistoryMove.backOne:
+        return recorder!.cur - 1;
     }
-    return _gotoHistory(index);
   }
 
-  Future<String> takeBack() async {
-    return _gotoHistory(recorder!.cur - 1);
-  }
+  Future<void> _gotoHistoryPlaySound(HistoryMove move) async {
+    if (!Config.keepMuteWhenTakingBack) {
+      switch (move) {
+        case HistoryMove.forwardAll:
+        case HistoryMove.farward:
+          await Audios.playTone(Sound.place);
+          break;
+        case HistoryMove.backAll:
+        case HistoryMove.backN:
 
-  Future<String> stepForward() async {
-    return _gotoHistory(recorder!.cur + 1);
-  }
-
-  Future<String> takeBackAll() async {
-    return _gotoHistory(-1);
-  }
-
-  Future<String> stepForwardAll() async {
-    return _gotoHistory(recorder!.history.length - 1);
+        case HistoryMove.backOne:
+          await Audios.playTone(Sound.remove);
+      }
+    }
   }
 
   String movesSinceLastRemove() {
@@ -1205,3 +1221,5 @@ class Position {
 
   String? get lastPositionWithRemove => recorder!.lastPositionWithRemove;
 }
+
+enum HistoryMove { forwardAll, backAll, farward, backN, backOne }
diff --git a/src/ui/flutter_app/lib/screens/game_page/game_page.dart b/src/ui/flutter_app/lib/screens/game_page/game_page.dart
index 8375a3d1..9b6797cd 100644
--- a/src/ui/flutter_app/lib/screens/game_page/game_page.dart
+++ b/src/ui/flutter_app/lib/screens/game_page/game_page.dart
@@ -172,7 +172,7 @@ class _GamePageState extends State<GamePage>
     }
   }
 
-  dynamic onBoardTap(int index) {
+  Future<dynamic> onBoardTap(int index) async {
     if (!isReady) {
       debugPrint("[tap] Not ready, ignore tapping.");
       return false;
@@ -208,18 +208,18 @@ class _GamePageState extends State<GamePage>
       gameInstance.newGame();
 
       if (gameInstance.isAiToMove) {
-        if (gameInstance.aiIsSearching()) {
+        if (gameInstance.aiIsSearching) {
           debugPrint("$tag AI is thinking, skip tapping.");
           return false;
         } else {
           debugPrint("[tap] AI is not thinking. AI is to move.");
-          engineToGo(false);
+          await engineToGo(false);
           return false;
         }
       }
     }
 
-    if (gameInstance.isAiToMove || gameInstance.aiIsSearching()) {
+    if (gameInstance.isAiToMove || gameInstance.aiIsSearching) {
       debugPrint("[tap] AI's turn, skip tapping.");
       return false;
     }
@@ -231,12 +231,12 @@ class _GamePageState extends State<GamePage>
     // Human to go
 
     bool ret = false;
-    Chain.capture(() {
+    await Chain.capture(() async {
       switch (position.action) {
         case Act.place:
-          if (position.putPiece(sq)) {
+          if (await position.putPiece(sq)) {
             if (position.action == Act.remove) {
-              //Audios.playTone(Audios.millSoundId);
+              //Audios.playTone(Audios.mill);
               if (mounted) {
                 showTip(S.of(context).tipMill);
                 if (Config.screenReaderSupport) {
@@ -244,7 +244,7 @@ class _GamePageState extends State<GamePage>
                 }
               }
             } else {
-              //Audios.playTone(Audios.placeSoundId);
+              //Audios.playTone(Audios.place);
               if (gameInstance.engineType == EngineType.humanVsAi && mounted) {
                 if (rule.mayOnlyRemoveUnplacedPieceInPlacingPhase) {
                   showTip(S.of(context).continueToMakeMove);
@@ -296,7 +296,7 @@ class _GamePageState extends State<GamePage>
           final int selectRet = position.selectPiece(sq);
           switch (selectRet) {
             case 0:
-              Audios.playTone(Audios.selectSoundId);
+              await Audios.playTone(Sound.select);
               gameInstance.select(index);
               ret = true;
               debugPrint("[tap] selectPiece: [$sq]");
@@ -325,7 +325,7 @@ class _GamePageState extends State<GamePage>
 
               break;
             case -2:
-              Audios.playTone(Audios.illegalSoundId);
+              await Audios.playTone(Sound.illegal);
               debugPrint("[tap] selectPiece: skip [$sq]");
               if (mounted && position.phase != Phase.gameOver) {
                 showTip(S.of(context).tipCannotMove);
@@ -336,7 +336,7 @@ class _GamePageState extends State<GamePage>
               }
               break;
             case -3:
-              Audios.playTone(Audios.illegalSoundId);
+              await Audios.playTone(Sound.illegal);
               debugPrint("[tap] selectPiece: skip [$sq]");
               if (mounted) {
                 showTip(S.of(context).tipCanMoveOnePoint);
@@ -347,7 +347,7 @@ class _GamePageState extends State<GamePage>
               }
               break;
             case -4:
-              Audios.playTone(Audios.illegalSoundId);
+              await Audios.playTone(Sound.illegal);
               debugPrint("[tap] selectPiece: skip [$sq]");
               if (mounted) {
                 showTip(S.of(context).tipSelectPieceToMove);
@@ -357,7 +357,7 @@ class _GamePageState extends State<GamePage>
               }
               break;
             default:
-              Audios.playTone(Audios.illegalSoundId);
+              await Audios.playTone(Sound.illegal);
               debugPrint("[tap] selectPiece: skip [$sq]");
               if (mounted) {
                 showTip(S.of(context).tipSelectWrong);
@@ -372,11 +372,11 @@ class _GamePageState extends State<GamePage>
           break;
 
         case Act.remove:
-          final int removeRet = position.removePiece(sq);
+          final int removeRet = await position.removePiece(sq);
 
           switch (removeRet) {
             case 0:
-              //Audios.playTone(Audios.removeSoundId);
+              //Audios.playTone(Audios.remove);
               ret = true;
               debugPrint("[tap] removePiece: [$sq]");
               if (gameInstance.position.pieceToRemoveCount >= 1) {
@@ -404,7 +404,7 @@ class _GamePageState extends State<GamePage>
               }
               break;
             case -2:
-              Audios.playTone(Audios.illegalSoundId);
+              await Audios.playTone(Sound.illegal);
               debugPrint(
                 "[tap] removePiece: Cannot Remove our pieces, skip [$sq]",
               );
@@ -416,7 +416,7 @@ class _GamePageState extends State<GamePage>
               }
               break;
             case -3:
-              Audios.playTone(Audios.illegalSoundId);
+              await Audios.playTone(Sound.illegal);
               debugPrint(
                 "[tap] removePiece: Cannot remove piece from Mill, skip [$sq]",
               );
@@ -432,7 +432,7 @@ class _GamePageState extends State<GamePage>
               }
               break;
             default:
-              Audios.playTone(Audios.illegalSoundId);
+              await Audios.playTone(Sound.illegal);
               debugPrint("[tap] removePiece: skip [$sq]");
               if (mounted && position.phase != Phase.gameOver) {
                 showTip(S.of(context).tipBanRemove);
@@ -587,7 +587,7 @@ class _GamePageState extends State<GamePage>
             );
           }
 
-          gameInstance.doMove(move.move!);
+          await gameInstance.doMove(move.move!);
           showTips();
           if (Config.screenReaderSupport && move.notation != null) {
             showSnackBar(context, "${S.of(context).ai}: ${move.notation!}");
@@ -657,7 +657,7 @@ class _GamePageState extends State<GamePage>
     debugPrint("Clipboard text:");
     debugPrint(text);
 
-    await onTakeBackAllButtonPressed(pop: false);
+    await onTakeBackAllButtonPressed(false);
     gameInstance.position.recorder!.clear();
     final importFailedStr = gameInstance.position.recorder!.import(text);
 
@@ -670,7 +670,7 @@ class _GamePageState extends State<GamePage>
       return;
     }
 
-    await onStepForwardAllButtonPressed(pop: false);
+    await onStepForwardAllButtonPressed(false);
 
     showTip(S.of(context).gameImported);
     if (Config.screenReaderSupport) {
@@ -774,8 +774,8 @@ class _GamePageState extends State<GamePage>
   Future<void> onAutoReplayButtonPressed() async {
     Navigator.pop(context);
 
-    await onTakeBackAllButtonPressed(pop: false);
-    await onStepForwardAllButtonPressed(pop: false);
+    await onTakeBackAllButtonPressed(false);
+    await onStepForwardAllButtonPressed(false);
   }
 
   void onGameButtonPressed() {
@@ -969,8 +969,9 @@ class _GamePageState extends State<GamePage>
   }
 
   Future<void> onGotoHistoryButtonsPressed(
-    Future<String> func, {
+    HistoryMove move, {
     bool pop = true,
+    int? number,
   }) async {
     if (pop == true) {
       Navigator.pop(context);
@@ -989,9 +990,7 @@ class _GamePageState extends State<GamePage>
 
     isGoingToHistory = true;
 
-    Audios.isTemporaryMute = Config.keepMuteWhenTakingBack;
-
-    final errMove = await func;
+    final errMove = await gameInstance.position.gotoHistory(move, number);
 
     switch (errMove) {
       case "":
@@ -1008,14 +1007,10 @@ class _GamePageState extends State<GamePage>
         break;
     }
 
-    Audios.isTemporaryMute = false;
-
     isGoingToHistory = false;
 
     if (mounted) {
-      String text = "";
       final pos = gameInstance.position;
-
       /*
       String us = "";
       String them = "";
@@ -1028,6 +1023,7 @@ class _GamePageState extends State<GamePage>
       }
       */
 
+      late final String text;
       final lastEffectiveMove = pos.recorder!.lastEffectiveMove;
       if (lastEffectiveMove != null && lastEffectiveMove.notation != null) {
         text = "${S.of(context).lastMove}: ${lastEffectiveMove.notation}";
@@ -1044,28 +1040,37 @@ class _GamePageState extends State<GamePage>
     }
   }
 
-  Future<void> onTakeBackButtonPressed({bool pop = true}) async {
-    onGotoHistoryButtonsPressed(gameInstance.position.takeBack(), pop: pop);
-  }
+  Future<void> onTakeBackButtonPressed([bool pop = true]) async =>
+      onGotoHistoryButtonsPressed(
+        HistoryMove.backOne,
+        pop: pop,
+      );
 
-  Future<void> onStepForwardButtonPressed({bool pop = true}) async {
-    onGotoHistoryButtonsPressed(gameInstance.position.stepForward(), pop: pop);
-  }
+  Future<void> onStepForwardButtonPressed([bool pop = true]) async =>
+      onGotoHistoryButtonsPressed(
+        HistoryMove.farward,
+        pop: pop,
+      );
 
-  Future<void> onTakeBackAllButtonPressed({bool pop = true}) async {
-    onGotoHistoryButtonsPressed(gameInstance.position.takeBackAll(), pop: pop);
-  }
+  Future<void> onTakeBackAllButtonPressed([bool pop = true]) async =>
+      onGotoHistoryButtonsPressed(
+        HistoryMove.backAll,
+        pop: pop,
+      );
 
-  Future<void> onStepForwardAllButtonPressed({bool pop = true}) async {
+  Future<void> onStepForwardAllButtonPressed([bool pop = true]) async {
     onGotoHistoryButtonsPressed(
-      gameInstance.position.stepForwardAll(),
+      HistoryMove.forwardAll,
       pop: pop,
     );
   }
 
-  Future<void> onTakeBackNButtonPressed(int n, {bool pop = true}) async {
-    onGotoHistoryButtonsPressed(gameInstance.position.takeBackN(n), pop: pop);
-  }
+  Future<void> onTakeBackNButtonPressed(int n, [bool pop = true]) async =>
+      onGotoHistoryButtonsPressed(
+        HistoryMove.backN,
+        number: n,
+        pop: pop,
+      );
 
   void onMoveListButtonPressed() {
     final moveHistoryText = gameInstance.position.moveHistoryText;
@@ -1177,7 +1182,7 @@ class _GamePageState extends State<GamePage>
 
     debugPrint("[config] isPrivacyPolicyAccepted: $value");
 
-    Config.save();
+    await Config.save();
   }
 
   Future<void> onShowPrivacyDialog() async {
@@ -1259,10 +1264,10 @@ class _GamePageState extends State<GamePage>
 
     switch (result) {
       case GameResult.win:
-        //Audios.playTone(Audios.winSoundId);
+        //Audios.playTone(Audios.win);
         break;
       case GameResult.lose:
-        //Audios.playTone(Audios.loseSoundId);
+        //Audios.playTone(Audios.lose);
         break;
       case GameResult.draw:
         break;
@@ -1694,7 +1699,7 @@ class _GamePageState extends State<GamePage>
           color: Color(Config.navigationToolbarIconColor),
         ),
       ),
-      onPressed: () => onTakeBackAllButtonPressed(pop: false),
+      onPressed: () => onTakeBackAllButtonPressed(false),
     );
 
     final takeBackButton = TextButton(
@@ -1707,7 +1712,7 @@ class _GamePageState extends State<GamePage>
           color: Color(Config.navigationToolbarIconColor),
         ),
       ),
-      onPressed: () => onTakeBackButtonPressed(pop: false),
+      onPressed: () async => onTakeBackButtonPressed(false),
     );
 
     final stepForwardButton = TextButton(
@@ -1720,7 +1725,7 @@ class _GamePageState extends State<GamePage>
           color: Color(Config.navigationToolbarIconColor),
         ),
       ),
-      onPressed: () => onStepForwardButtonPressed(pop: false),
+      onPressed: () async => onStepForwardButtonPressed(false),
     );
 
     final stepForwardAllButton = TextButton(
@@ -1733,7 +1738,7 @@ class _GamePageState extends State<GamePage>
           color: Color(Config.navigationToolbarIconColor),
         ),
       ),
-      onPressed: () => onStepForwardAllButtonPressed(pop: false),
+      onPressed: () async => onStepForwardAllButtonPressed(false),
     );
 
     return GamePageToolBar(
diff --git a/src/ui/flutter_app/lib/services/audios.dart b/src/ui/flutter_app/lib/services/audios.dart
index 1c7dabbc..07f8d907 100644
--- a/src/ui/flutter_app/lib/services/audios.dart
+++ b/src/ui/flutter_app/lib/services/audios.dart
@@ -24,22 +24,35 @@ import 'package:sanmill/shared/common/config.dart';
 import 'package:soundpool/soundpool.dart';
 import 'package:stack_trace/stack_trace.dart';
 
+enum Sound {
+  draw,
+  fly,
+  go,
+  illegal,
+  lose,
+  mill,
+  place,
+  remove,
+  select,
+  win,
+}
+
 class Audios {
   const Audios._();
   //static AudioPlayer? _player;
-  static Soundpool? _soundpool;
-  // TODO: use enum for the sounds
-  static int? _alarmSoundStreamId;
-  static int? drawSoundId;
-  static int? flySoundId;
-  static int? goSoundId;
-  static int? illegalSoundId;
-  static int? loseSoundId;
-  static int? millSoundId;
-  static int? placeSoundId;
-  static int? removeSoundId;
-  static int? selectSoundId;
-  static int? winSoundId;
+  static final Soundpool _soundpool = Soundpool.fromOptions();
+  static bool _initialized = false;
+  static int _alarmSoundStreamId = 0;
+  static late final int _drawSoundId;
+  static late final int _flySoundId;
+  static late final int _goSoundId;
+  static late final int _illegalSoundId;
+  static late final int _loseSoundId;
+  static late final int _millSoundId;
+  static late final int _placeSoundId;
+  static late final int _removeSoundId;
+  static late final int _selectSoundId;
+  static late final int _winSoundId;
   static bool isTemporaryMute = false;
 
   static Future<void> loadSounds() async {
@@ -48,156 +61,110 @@ class Audios {
       return;
     }
 
-    _soundpool ??= Soundpool.fromOptions();
+    _drawSoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/draw.mp3"),
+    );
 
-    if (_soundpool == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: _soundpool is null.");
-      return;
-    }
+    _flySoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/fly.mp3"),
+    );
 
-    drawSoundId ??=
-        await _soundpool!.load(await rootBundle.load("assets/audios/draw.mp3"));
-    if (drawSoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: drawSoundId is null.");
-      return;
-    }
+    _goSoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/go.mp3"),
+    );
 
-    flySoundId ??=
-        await _soundpool!.load(await rootBundle.load("assets/audios/fly.mp3"));
-    if (flySoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: flySoundId is null.");
-      return;
-    }
+    _illegalSoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/illegal.mp3"),
+    );
 
-    goSoundId ??=
-        await _soundpool!.load(await rootBundle.load("assets/audios/go.mp3"));
-    if (goSoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: goSoundId is null.");
-      return;
-    }
+    _loseSoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/lose.mp3"),
+    );
 
-    illegalSoundId = await _soundpool!
-        .load(await rootBundle.load("assets/audios/illegal.mp3"));
-    if (illegalSoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: illegalSoundId is null.");
-      return;
-    }
+    _millSoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/mill.mp3"),
+    );
 
-    loseSoundId ??=
-        await _soundpool!.load(await rootBundle.load("assets/audios/lose.mp3"));
-    if (loseSoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: loseSoundId is null.");
-      return;
-    }
+    _placeSoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/place.mp3"),
+    );
 
-    millSoundId ??=
-        await _soundpool!.load(await rootBundle.load("assets/audios/mill.mp3"));
-    if (millSoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: millSoundId is null.");
-      return;
-    }
+    _removeSoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/remove.mp3"),
+    );
 
-    placeSoundId ??= await _soundpool!
-        .load(await rootBundle.load("assets/audios/place.mp3"));
-    if (placeSoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: placeSoundId is null.");
-      return;
-    }
+    _selectSoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/select.mp3"),
+    );
 
-    removeSoundId ??= await _soundpool!
-        .load(await rootBundle.load("assets/audios/remove.mp3"));
-    if (removeSoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: removeSoundId is null.");
-      return;
-    }
+    _winSoundId = await _soundpool.load(
+      await rootBundle.load("assets/audios/win.mp3"),
+    );
 
-    selectSoundId ??= await _soundpool!
-        .load(await rootBundle.load("assets/audios/select.mp3"));
-    if (selectSoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: selectSoundId is null.");
-      return;
-    }
-
-    winSoundId ??=
-        await _soundpool!.load(await rootBundle.load("assets/audios/win.mp3"));
-    if (winSoundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: winSoundId is null.");
-      return;
-    }
+    _initialized = true;
   }
 
-  static Future<void> _playSound(int? soundId) async {
-    if (Platform.isWindows) {
-      return;
+  static Future<void> _playSound(Sound sound) async {
+    assert(!Platform.isWindows);
+
+    late final int soundId;
+
+    switch (sound) {
+      case Sound.draw:
+        soundId = _drawSoundId;
+        break;
+      case Sound.fly:
+        soundId = _flySoundId;
+        break;
+      case Sound.go:
+        soundId = _goSoundId;
+        break;
+      case Sound.illegal:
+        soundId = _illegalSoundId;
+        break;
+      case Sound.lose:
+        soundId = _loseSoundId;
+        break;
+      case Sound.mill:
+        soundId = _millSoundId;
+        break;
+      case Sound.place:
+        soundId = _placeSoundId;
+        break;
+      case Sound.remove:
+        soundId = _removeSoundId;
+        break;
+      case Sound.select:
+        soundId = _selectSoundId;
+        break;
+      case Sound.win:
+        soundId = _winSoundId;
+        break;
     }
 
-    if (soundId == null) {
-      if (Config.developerMode) {
-        assert(false);
-      }
-      debugPrint("[audio] Error: soundId is null.");
-      return;
-    }
-
-    _alarmSoundStreamId = await _soundpool!.play(soundId);
+    _alarmSoundStreamId = await _soundpool.play(soundId);
   }
 
   static Future<void> _stopSound() async {
-    if (Platform.isWindows) {
-      return;
-    }
+    assert(!Platform.isWindows);
 
-    if (_alarmSoundStreamId != null && _alarmSoundStreamId! > 0) {
-      await _soundpool!.stop(_alarmSoundStreamId!);
+    if (_alarmSoundStreamId > 0) {
+      await _soundpool.stop(_alarmSoundStreamId);
     }
   }
 
-  static Future<void> disposePool() async {
-    if (Platform.isWindows) {
-      return;
-    }
+  static void disposePool() {
+    assert(!Platform.isWindows);
 
-    _soundpool!.dispose();
+    _soundpool.dispose();
   }
 
-  static Future<void> playTone(int? soundId) async {
-    Chain.capture(() async {
+  static Future<void> playTone(Sound sound) async {
+    await Chain.capture(() async {
       if (!Config.toneEnabled ||
           isTemporaryMute ||
-          Config.screenReaderSupport) {
+          Config.screenReaderSupport ||
+          !_initialized) {
         return;
       }
 
@@ -206,14 +173,11 @@ class Audios {
         return;
       }
 
+      // TODO: isn't debug chain meant to catch errors? so why catching them in here and not in onError??
       try {
-        if (_soundpool == null) {
-          await loadSounds();
-        }
-
         await _stopSound();
 
-        _playSound(soundId);
+        await _playSound(sound);
       } catch (e) {
         // Fallback for all errors
         debugPrint(e.toString());
diff --git a/src/ui/flutter_app/lib/shared/drawer_controller.dart b/src/ui/flutter_app/lib/shared/drawer_controller.dart
index 94a14dfe..2ebde3e7 100644
--- a/src/ui/flutter_app/lib/shared/drawer_controller.dart
+++ b/src/ui/flutter_app/lib/shared/drawer_controller.dart
@@ -111,7 +111,7 @@ class _DrawerControllerState extends State<DrawerController>
     super.initState();
   }
 
-  Future<bool> getInitState() async {
+  bool getInitState() {
     scrollController.jumpTo(
       widget.drawerWidth,
     );