Partly refactor position.dart

Change-Id: Idb9245b99f95fbe91712b1642190f8c7e48f2d60
calcitem · Apr 29, 2023 · 20920bd · 20920bd
1 parent 34cf90f
commit 20920bd
Showing 1 changed file with 73 additions and 29 deletions.
diff --git a/src/ui/flutter_app/lib/services/mill/src/position.dart b/src/ui/flutter_app/lib/services/mill/src/position.dart
@@ -401,14 +401,77 @@ class Position {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+  bool isWithinBoard(int s) {
+    return sqBegin <= s && s < sqEnd;
+  }
+
+  bool isSquareEmpty(int s) {
+    return _board[s] == PieceColor.none;
+  }
+
+  void increasePieceOnBoardCount(PieceColor color) {
+    if (pieceOnBoardCount[color] != null) {
+      pieceOnBoardCount[color] = pieceOnBoardCount[color]! + 1;
+    }
+  }
+
+  void decreasePieceInHandCount(PieceColor color) {
+    if (pieceInHandCount[color] != null) {
+      pieceInHandCount[color] = pieceInHandCount[color]! - 1;
+    }
+  }
+
+  bool canPlacePiece(int s) {
+    if (phase == Phase.gameOver ||
+        action != Act.place ||
+        !isWithinBoard(s) ||
+        !isSquareEmpty(s)) {
+      return false;
+    }
+    return true;
+  }
+
+  bool canMovePiece(int from, int to) {
+    int md;
+
+    if (phase != Phase.moving ||
+        (pieceOnBoardCount[sideToMove]! > DB().ruleSettings.flyPieceCount &&
+            !DB().ruleSettings.mayFly)) {
+      return false;
+    }
+
+    for (md = 0; md < moveDirectionNumber; md++) {
+      if (to == _adjacentSquares[from][md]) {
+        break;
+      }
+    }
+
+    // Not in moveTable
+    if (md == moveDirectionNumber) {
+      logger.i(
+        "[position] putPiece: [$to] is not in [$from]'s move table.",
+      );
+      return false;
+    }
+
+    return true;
+  }
+
+  bool isGameOverMaterialConditionMet() {
+    if (pieceOnBoardCount[_them]! + pieceInHandCount[_them]! <
+        DB().ruleSettings.piecesAtLeastCount) {
+      return true;
+    }
+    return false;
+  }
+
+  //////////////////////////////////////////////////////////////////////////////
+
   bool _putPiece(int s) {
     PieceColor piece = PieceColor.none;
     final PieceColor us = _sideToMove;
 
-    if (phase == Phase.gameOver ||
-        action != Act.place ||
-        !(sqBegin <= s && s < sqEnd) ||
-        _board[s] != PieceColor.none) {
+    if (!canPlacePiece(s)) {
       return false;
     }
 
@@ -423,12 +486,10 @@ class Position {
                 .showSnackBarClear("FEN: ${MillController().position.fen}");
             return false;
           }
-          pieceInHandCount[us] = pieceInHandCount[us]! - 1;
+          decreasePieceInHandCount(us);
         }
 
-        if (pieceOnBoardCount[us] != null) {
-          pieceOnBoardCount[us] = pieceOnBoardCount[us]! + 1;
-        }
+        increasePieceOnBoardCount(us);
 
         _grid[squareToIndex[s]!] = piece;
         _board[s] = piece;
@@ -485,8 +546,7 @@ class Position {
 
           if (DB().ruleSettings.mayOnlyRemoveUnplacedPieceInPlacingPhase &&
               pieceInHandCount[_them] != null) {
-            pieceInHandCount[_them] =
-                pieceInHandCount[_them]! - 1; // Or pieceToRemoveCount?
+            decreasePieceInHandCount(_them); // Or pieceToRemoveCount?
 
             if (pieceInHandCount[_them]! < 0) {
               pieceInHandCount[_them] = 0;
@@ -523,23 +583,8 @@ class Position {
         }
 
         // If illegal
-        if (pieceOnBoardCount[sideToMove]! > DB().ruleSettings.flyPieceCount ||
-            !DB().ruleSettings.mayFly) {
-          int md;
-
-          for (md = 0; md < moveDirectionNumber; md++) {
-            if (s == _adjacentSquares[_currentSquare][md]) {
-              break;
-            }
-          }
-
-          // Not in moveTable
-          if (md == moveDirectionNumber) {
-            logger.i(
-              "[position] putPiece: [$s] is not in [$_currentSquare]'s move table.",
-            );
-            return false;
-          }
+        if (!canMovePiece(_currentSquare, s)) {
+          return false;
         }
 
         _record = ExtMove(
@@ -646,8 +691,7 @@ class Position {
       pieceOnBoardCount[_them] = pieceOnBoardCount[_them]! - 1;
     }
 
-    if (pieceOnBoardCount[_them]! + pieceInHandCount[_them]! <
-        DB().ruleSettings.piecesAtLeastCount) {
+    if (isGameOverMaterialConditionMet()) {
       _setGameOver(sideToMove, GameOverReason.loseLessThanThree);
       Audios().playTone(Sound.remove);
       return const MillResponseOK();