check and checkmate dynamics, first steps

src/backend/Board.java

@@ -186,6 +186,13 @@ public class Board {
 	    if (isKingInCheck(false)) {
 	        System.out.println("Black is in check!");
 	    }
+	    
+	    if (isCheckmate(true)) {
+	        System.out.println("White is in checkmate!");
+	    }
+	    if (isCheckmate(false)) {
+	        System.out.println("Black is in checkmate!");
+	    }
 	}
 
 	public boolean isSelected(int x, int y) {
@@ -239,8 +246,21 @@ public class Board {
 	}
 
 	public Board(Board board) {
-		//TODO
+	    this.colNum = board.colNum;
+	    this.lineNum = board.lineNum;
+	    this.turnNumber = board.turnNumber;
+	    this.isWhiteTurn = board.isWhiteTurn;
 
+	    this.pieces = new ArrayList<>();
+	    for (int i = 0; i < board.pieces.size(); i++) {
+	        Piece original = board.pieces.get(i);
+	        Piece copy = new Piece(original.getX(), original.getY(), original.isWhite(), original.getType());
+	        this.pieces.add(copy);
+	    }
+
+	    this.selectedX = -1;
+	    this.selectedY = -1;
+	    this.highlightedSquares = new ArrayList<>();
 	}
 	
 	public void playMove(Move move) {
@@ -271,28 +291,82 @@ public class Board {
 	
 	public boolean isKingInCheck(boolean whiteKing) {
 	    Piece king = null;
-	    for (Piece p : pieces) {
+
+	    for (int i = 0; i < pieces.size(); i++) {
+	        Piece p = pieces.get(i);
 	        if (p.getType() == PieceType.King && p.isWhite() == whiteKing) {
 	            king = p;
 	        }
 	    }
 
+	    boolean inCheck = false;
+
+	    if (king != null) {
 	        int kingX = king.getX();
 	        int kingY = king.getY();
-
+	        for (int i = 0; i < pieces.size(); i++) {
-	    for (Piece p : pieces) {
+	            Piece p = pieces.get(i);
 	            if (p.isWhite() != whiteKing) {
-	            ArrayList<int[]> enemyMoves = getValidMoves(p);
+	                ArrayList<int[]> moves = getValidMoves(p);
 
-	            for (int[] move : enemyMoves) {
+	                for (int j = 0; j < moves.size(); j++) {
+	                    int[] move = moves.get(j);
 	                    if (move[0] == kingX && move[1] == kingY) {
-	                    return true;
+	                        inCheck = true;
+	                    }
 	                }
 	            }
 	        }
 	    }
 
-	    return false;
+	    return inCheck;
+	}
+	
+	public boolean isCheckmate(boolean whiteKing) {
+	    boolean kingInCheck = isKingInCheck(whiteKing);
+	    boolean hasEscape = false;
+
+	    if (kingInCheck) {
+	        for (int i = 0; i < pieces.size(); i++) {
+	            Piece piece = pieces.get(i);
+
+	            if (piece.isWhite() == whiteKing) {
+	                ArrayList<int[]> moves = getValidMoves(piece);
+
+	                for (int j = 0; j < moves.size(); j++) {
+	                    int[] move = moves.get(j);
+	                    int newX = move[0];
+	                    int newY = move[1];
+
+	                    // Simulate the board
+	                    Board simBoard = new Board(this);
+	                    Piece simPiece = simBoard.getPieceAt(piece.getX(), piece.getY());
+	                    Piece captured = simBoard.getPieceAt(newX, newY);
+
+	                    if (captured != null) {
+	                        simBoard.getPieces().remove(captured);
+	                    }
+
+	                    simPiece.setX(newX);
+	                    simPiece.setY(newY);
+
+	                    boolean stillInCheck = simBoard.isKingInCheck(whiteKing);
+
+	                    if (!stillInCheck) {
+	                        hasEscape = true;
+	                    }
+	                }
+	            }
+	        }
+	    }
+
+	    boolean checkmate = false;
+
+	    if (kingInCheck && !hasEscape) {
+	        checkmate = true;
+	    }
+
+	    return checkmate;
 	}
  
 }