modules/core/src/main/scala/de/nowchess/chess/controller/GameController.scala

@@ -59,7 +59,7 @@ object GameController:
                         (b.removed(capturedSq), board.pieceAt(capturedSq))
                       else (b, cap)
                   val newHistory = history.addMove(from, to, castleOpt)
-                  GameRules.gameStatus(newBoard, newHistory, turn.opposite) match
+                  GameRules.gameStatus(newBoard, newHistory)(turn.opposite) match
                     case PositionStatus.Normal  => MoveResult.Moved(newBoard, newHistory, captured, turn.opposite)
                     case PositionStatus.InCheck => MoveResult.MovedInCheck(newBoard, newHistory, captured, turn.opposite)
                     case PositionStatus.Mated   => MoveResult.Checkmate(turn)

modules/core/src/main/scala/de/nowchess/chess/logic/GameRules.scala

@@ -9,7 +9,7 @@ enum PositionStatus:
 object GameRules:
 
   /** True if `color`'s king is under attack on this board. */
-  def isInCheck(board: Board, color: Color): Boolean =
+  def isInCheck(board: Board)(color: Color): Boolean =
     board.pieces
       .collectFirst { case (sq, p) if p.color == color && p.pieceType == PieceType.King => sq }
       .exists { kingSq =>
@@ -21,7 +21,7 @@ object GameRules:
       }
 
   /** All (from, to) moves for `color` that do not leave their own king in check. */
-  def legalMoves(board: Board, history: GameHistory, color: Color): Set[(Square, Square)] =
+  def legalMoves(board: Board, history: GameHistory)(color: Color): Set[(Square, Square)] =
     val targets = MoveValidator.legalTargets(board, history)
     board.pieces
       .collect { case (from, piece) if piece.color == color => from }
@@ -33,16 +33,16 @@ object GameRules:
                 board.withCastle(color, MoveValidator.castleSide(from, to))
               else
                 board.withMove(from, to)._1
-            !isInCheck(newBoard, color)
+            !isInCheck(newBoard)(color)
           }
           .map(to => from -> to)
       }
       .toSet
 
   /** Position status for the side whose turn it is (`color`). */
-  def gameStatus(board: Board, history: GameHistory, color: Color): PositionStatus =
-    val moves   = legalMoves(board, history, color)
-    val inCheck = isInCheck(board, color)
+  def gameStatus(board: Board, history: GameHistory)(color: Color): PositionStatus =
+    val moves   = legalMoves(board, history)(color)
+    val inCheck = isInCheck(board)(color)
     if moves.isEmpty && inCheck then PositionStatus.Mated
     else if moves.isEmpty       then PositionStatus.Drawn
     else if inCheck             then PositionStatus.InCheck

modules/core/src/main/scala/de/nowchess/chess/logic/MoveValidator.scala

@@ -133,7 +133,7 @@ object MoveValidator:
     val enemy  = color.opposite
 
     if !board.pieceAt(kingSq).contains(Piece(color, PieceType.King)) ||
-       GameRules.isInCheck(board, color) then Set.empty
+       GameRules.isInCheck(board)(color) then Set.empty
     else
       val kingsideSq = Option.when(
         rights.kingSide &&

modules/core/src/test/scala/de/nowchess/chess/logic/GameRulesTest.scala

@@ -13,38 +13,34 @@ class GameRulesTest extends AnyFunSuite with Matchers:
 
   /** Wrap a board in a GameContext with no castling rights — for non-castling tests. */
   private def testLegalMoves(entries: (Square, Piece)*)(color: Color): Set[(Square, Square)] =
-    GameRules.legalMoves(Board(entries.toMap), GameHistory.empty, color)
+    GameRules.legalMoves(Board(entries.toMap), GameHistory.empty)(color)
 
   private def testGameStatus(entries: (Square, Piece)*)(color: Color): PositionStatus =
-    GameRules.gameStatus(Board(entries.toMap), GameHistory.empty, color)
+    GameRules.gameStatus(Board(entries.toMap), GameHistory.empty)(color)
 
   // ──── isInCheck ──────────────────────────────────────────────────────
 
   test("isInCheck: king attacked by enemy rook on same rank"):
-    // White King E1, Black Rook A1 — rook slides along rank 1 to E1
     val b = board(
       sq(File.E, Rank.R1) -> Piece.WhiteKing,
       sq(File.A, Rank.R1) -> Piece.BlackRook
     )
-    GameRules.isInCheck(b, Color.White) shouldBe true
+    GameRules.isInCheck(b)(Color.White) shouldBe true
 
   test("isInCheck: king not attacked"):
-    // Black Rook A3 does not cover E1
     val b = board(
       sq(File.E, Rank.R1) -> Piece.WhiteKing,
       sq(File.A, Rank.R3) -> Piece.BlackRook
     )
-    GameRules.isInCheck(b, Color.White) shouldBe false
+    GameRules.isInCheck(b)(Color.White) shouldBe false
 
   test("isInCheck: no king on board returns false"):
     val b = board(sq(File.A, Rank.R1) -> Piece.BlackRook)
-    GameRules.isInCheck(b, Color.White) shouldBe false
+    GameRules.isInCheck(b)(Color.White) shouldBe false
 
   // ──── legalMoves ─────────────────────────────────────────────────────
 
   test("legalMoves: move that exposes own king to rook is excluded"):
-    // White King E1, White Rook E4 (pinned on E-file), Black Rook E8
-    // Moving the White Rook off the E-file would expose the king
     val moves = testLegalMoves(
       sq(File.E, Rank.R1) -> Piece.WhiteKing,
       sq(File.E, Rank.R4) -> Piece.WhiteRook,
@@ -53,7 +49,6 @@ class GameRulesTest extends AnyFunSuite with Matchers:
     moves should not contain (sq(File.E, Rank.R4) -> sq(File.D, Rank.R4))
 
   test("legalMoves: move that blocks check is included"):
-    // White King E1 in check from Black Rook E8; White Rook A5 can interpose on E5
     val moves = testLegalMoves(
       sq(File.E, Rank.R1) -> Piece.WhiteKing,
       sq(File.A, Rank.R5) -> Piece.WhiteRook,
@@ -64,8 +59,6 @@ class GameRulesTest extends AnyFunSuite with Matchers:
   // ──── gameStatus ──────────────────────────────────────────────────────
 
   test("gameStatus: checkmate returns Mated"):
-    // White Qh8, Ka6; Black Ka8
-    // Qh8 attacks Ka8 along rank 8; all escape squares covered (spec-verified position)
     testGameStatus(
       sq(File.H, Rank.R8) -> Piece.WhiteQueen,
       sq(File.A, Rank.R6) -> Piece.WhiteKing,
@@ -73,8 +66,6 @@ class GameRulesTest extends AnyFunSuite with Matchers:
     )(Color.Black) shouldBe PositionStatus.Mated
 
   test("gameStatus: stalemate returns Drawn"):
-    // White Qb6, Kc6; Black Ka8
-    // Black king has no legal moves and is not in check (spec-verified position)
     testGameStatus(
       sq(File.B, Rank.R6) -> Piece.WhiteQueen,
       sq(File.C, Rank.R6) -> Piece.WhiteKing,
@@ -82,14 +73,13 @@ class GameRulesTest extends AnyFunSuite with Matchers:
     )(Color.Black) shouldBe PositionStatus.Drawn
 
   test("gameStatus: king in check with legal escape returns InCheck"):
-    // White Ra8 attacks Black Ke8 along rank 8; king can escape to d7, e7, f7
     testGameStatus(
       sq(File.A, Rank.R8) -> Piece.WhiteRook,
       sq(File.E, Rank.R8) -> Piece.BlackKing
     )(Color.Black) shouldBe PositionStatus.InCheck
 
   test("gameStatus: normal starting position returns Normal"):
-    GameRules.gameStatus(Board.initial, GameHistory.empty, Color.White) shouldBe PositionStatus.Normal
+    GameRules.gameStatus(Board.initial, GameHistory.empty)(Color.White) shouldBe PositionStatus.Normal
 
   test("legalMoves: includes castling destination when available"):
     val b = board(
@@ -97,7 +87,7 @@ class GameRulesTest extends AnyFunSuite with Matchers:
         sq(File.H, Rank.R1) -> Piece.WhiteRook,
         sq(File.H, Rank.R8) -> Piece.BlackKing
       )
-    GameRules.legalMoves(b, GameHistory.empty, Color.White) should contain(sq(File.E, Rank.R1) -> sq(File.G, Rank.R1))
+    GameRules.legalMoves(b, GameHistory.empty)(Color.White) should contain(sq(File.E, Rank.R1) -> sq(File.G, Rank.R1))
 
   test("legalMoves: excludes castling when king is in check"):
     val b = board(
@@ -106,13 +96,9 @@ class GameRulesTest extends AnyFunSuite with Matchers:
         sq(File.E, Rank.R8) -> Piece.BlackRook,
         sq(File.A, Rank.R8) -> Piece.BlackKing
       )
-    GameRules.legalMoves(b, GameHistory.empty, Color.White) should not contain (sq(File.E, Rank.R1) -> sq(File.G, Rank.R1))
+    GameRules.legalMoves(b, GameHistory.empty)(Color.White) should not contain (sq(File.E, Rank.R1) -> sq(File.G, Rank.R1))
 
   test("gameStatus: returns Normal (not Drawn) when castling is the only legal move"):
-    // White King e1, Rook h1 (kingside castling available).
-    // Black Rooks d2 and f2 box the king: d1 attacked by d2, e2 attacked by both,
-    // f1 attacked by f2. King cannot move to any adjacent square without entering
-    // an attacked square or an enemy piece. Only legal move: castle to g1.
     val b = board(
         sq(File.E, Rank.R1) -> Piece.WhiteKing,
         sq(File.H, Rank.R1) -> Piece.WhiteRook,
@@ -120,11 +106,9 @@ class GameRulesTest extends AnyFunSuite with Matchers:
         sq(File.F, Rank.R2) -> Piece.BlackRook,
         sq(File.A, Rank.R8) -> Piece.BlackKing
       )
-    // No history means castling rights are intact
-    GameRules.gameStatus(b, GameHistory.empty, Color.White) shouldBe PositionStatus.Normal
+    GameRules.gameStatus(b, GameHistory.empty)(Color.White) shouldBe PositionStatus.Normal
 
   test("CastleSide.withCastle correctly positions pieces for Queenside castling"):
-    // Directly test the withCastle extension for Queenside (coverage gap on line 10)
     val b = board(
       sq(File.E, Rank.R1) -> Piece.WhiteKing,
       sq(File.A, Rank.R1) -> Piece.WhiteRook,