check maths

OOP_1A2_Project/src/backend/Board.java

@@ -344,37 +344,19 @@ public class Board {
 	    highlightedPositions.clear();
 	    highlightedPositions.addAll(validMoves);
 	}
-	// Calculate valid moves for a piece
 	private Set<Position> getValidMoves(Piece piece) {
-	    Set<Position> validMoves = new HashSet<>();
+	    // Get all possible moves without considering check
+	    Set<Position> candidateMoves = getRawValidMoves(piece);
 	    
-	    int x = piece.getX();
-	    int y = piece.getY();
-	    boolean isWhite = piece.isWhite();
-	    
-	    switch (piece.getType()) {
-	        case Pawn:
-	            addPawnMoves(validMoves, x, y, isWhite);
-	            break;
-	        case Rook:
-	            addRookMoves(validMoves, x, y, isWhite);
-	            break;
-	        case Knight:
-	            addKnightMoves(validMoves, x, y, isWhite);
-	            break;
-	        case Bishop:
-	            addBishopMoves(validMoves, x, y, isWhite);
-	            break;
-	        case Queen:
-	            addRookMoves(validMoves, x, y, isWhite);
-	            addBishopMoves(validMoves, x, y, isWhite);
-	            break;
-	        case King:
-	            addKingMoves(validMoves, x, y, isWhite);
-	            break;
+	    // Filter out moves that would leave king in check
+	    Set<Position> legalMoves = new HashSet<>();
+	    for (Position move : candidateMoves) {
+	        if (!wouldMoveLeaveKingInCheck(piece, move.x, move.y)) {
+	            legalMoves.add(move);
+	        }
 	    }
 	    
-	    return validMoves;
+	    return legalMoves;
 	}
 
 	// Add valid pawn moves
@@ -522,6 +504,92 @@ public class Board {
 	        }
 	    }
 	}
+	// Add this method to check if a king is in check
+	private boolean isKingInCheck(boolean isWhiteKing) {
+	    // Find the king's position
+	    Piece king = null;
+	    for (Piece p : pieces) {
+	        if (p.getType() == PieceType.King && p.isWhite() == isWhiteKing) {
+	            king = p;
+	            break;
+	        }
+	    }
+	    
+	    if (king == null) return false;
+	    
+	    // Check if any opponent piece can attack the king
+	    for (Piece p : pieces) {
+	        if (p.isWhite() == isWhiteKing) continue; // Skip pieces of same color
+	        
+	        // Get raw moves without check validation
+	        Set<Position> attackMoves = getRawValidMoves(p);
+	        
+	        // If any piece can move to king's position, king is in check
+	        if (attackMoves.contains(new Position(king.getX(), king.getY()))) {
+	            return true;
+	        }
+	    }
+	    
+	    return false;
+	}
+
+	// Add this method to simulate a move and check if it leaves king in check
+	private boolean wouldMoveLeaveKingInCheck(Piece piece, int newX, int newY) {
+	    // Create temporary board to simulate move
+	    Board tempBoard = new Board(this);
+	    
+	    // Find the piece in the temp board
+	    Piece tempPiece = null;
+	    for (Piece p : tempBoard.pieces) {
+	        if (p.getX() == piece.getX() && p.getY() == piece.getY()) {
+	            tempPiece = p;
+	            break;
+	        }
+	    }
+	    
+	    if (tempPiece == null) return true; // Safety check
+	    
+	    // Remove any piece at destination
+	    Piece capturedPiece = tempBoard.getPieceAt(newX, newY);
+	    if (capturedPiece != null) {
+	        tempBoard.pieces.remove(capturedPiece);
+	    }
+	    
+	    // Move the piece
+	    tempPiece.moveTo(newX, newY);
+	    
+	    // Check if king is in check after move
+	    return tempBoard.isKingInCheck(piece.isWhite());
+	}
+
+	// Add this helper method to get moves without check validation
+	private Set<Position> getRawValidMoves(Piece piece) {
+	    Set<Position> moves = new HashSet<>();
+	    
+	    switch (piece.getType()) {
+	        case Pawn:
+	            addPawnMoves(moves, piece.getX(), piece.getY(), piece.isWhite());
+	            break;
+	        case Rook:
+	            addRookMoves(moves, piece.getX(), piece.getY(), piece.isWhite());
+	            break;
+	        case Knight:
+	            addKnightMoves(moves, piece.getX(), piece.getY(), piece.isWhite());
+	            break;
+	        case Bishop:
+	            addBishopMoves(moves, piece.getX(), piece.getY(), piece.isWhite());
+	            break;
+	        case Queen:
+	            addRookMoves(moves, piece.getX(), piece.getY(), piece.isWhite());
+	            addBishopMoves(moves, piece.getX(), piece.getY(), piece.isWhite());
+	            break;
+	        case King:
+	            addKingMoves(moves, piece.getX(), piece.getY(), piece.isWhite());
+	            break;
+	    }
+	    
+	    return moves;
+	}
 	public void playMove(Move move) {
 		//TODO