Board.hasAttackVector(), Board.checkAttackDirection(), and Piece.oppo…

…site() added

src/model/Board.java

@@ -4,9 +4,57 @@ public class Board {
 	private final int BOARD_SIZE = 8;
 	private Piece[][] representation;
 	private int movesSinceCapture;
+	public enum Direction {UP, DOWN, LEFT, RIGHT};
 
 	public Board() {
 		representation = new Piece[BOARD_SIZE][BOARD_SIZE];
+		movesSinceCapture = 0;
+	}
+
+	public boolean isValidSquare(int i, int j) {
+		return i < BOARD_SIZE && j < BOARD_SIZE;
+	}
+
+	/**
+	 * Checks if a piece can attack another in a given direction.
+	 * @param p The piece.
+	 * @param X The direction along the x-coordinate (LEFT or RIGHT).
+	 * @param Y The direction along the y-coordinate (UP or DOWN).
+	 * @return
+	 */
+	public boolean checkAttackDirection(Piece p, Direction X, Direction Y) {
+		Piece candidate = null;
+		int i = p.getX(), j = p.getY();
+		int enemy_i = X.equals(Direction.LEFT) ? i-1 : i+1;
+		int enemy_j = Y.equals(Direction.UP) ? j+1 : j-1;
+		int end_position_i = X.equals(Direction.LEFT) ? i-2 : i+2;
+		int end_position_j = Y.equals(Direction.UP) ? j+2: j-2;
+		if (isValidSquare(enemy_i, enemy_j)) {
+			candidate = representation[enemy_i][enemy_j];
+			if (null != candidate && // there exists a piece we can take)
+				candidate.color.equals(p.opposite()) && // it is an enemy piece
+				isValidSquare(end_position_i, end_position_j) && // there is a free space
+				null == representation[end_position_i][end_position_j]) // that we can end up in
+					return true;
+		}
+		return false;
+	}
+
+	/**
+	 * Used for validation of moves.
+	 * If returns true after a player chooses a move,
+	 * that move is invalid because the player can keep on attacking.
+	 * @param p
+	 * @return
+	 */
+	public boolean hasAttackVector(Piece p) {
+		boolean can_attack = false;
+		can_attack |= checkAttackDirection(p, Direction.UP, Direction.LEFT);
+		can_attack |= checkAttackDirection(p, Direction.UP, Direction.RIGHT);
+		if(p.getType().equals(Type.KING)) {
+			can_attack |= checkAttackDirection(p, Direction.DOWN, Direction.LEFT);
+			can_attack |= checkAttackDirection(p, Direction.DOWN, Direction.RIGHT);
+		}
+		return can_attack;
 	}
-
 }

src/model/Piece.java

@@ -18,6 +18,12 @@ public void updateCoordinates(int x, int y) {
 		this.y = y;
 	}
 
+	public Color opposite() {
+		if(this.color.equals(Color.RED)) return Color.BLACK;
+		if(this.color.equals(Color.BLACK)) return Color.RED;
+		return null;
+	}
+
 	public int getX() {
 		return this.x;
 	}