static final long serialVersionUID = 1L;

	static final int PIECE = 1;

	static final int QUEEN = 2;

	final Piece white_super_sun = new Piece(new ImgComponent("images/white_super_sun.png").getImage(), "white", QUEEN,

			50);

	final Piece black_super_sun = new Piece(new ImgComponent("images/black_super_sun.png").getImage(), "black", QUEEN,

			50);

	void initBoard() {

		for (int i = 1; i < 8; i += 2)

			add(new ImgComponent("images/black_sun.png").getImage(), i, "black", PIECE);

		for (int i = 8; i < 15; i += 2)

			add(new ImgComponent("images/black_sun.png").getImage(), i, "black", PIECE);

		for (int i = 17; i <= 23; i += 2)

			add(new ImgComponent("images/black_sun.png").getImage(), i, "black", PIECE);

		for (int i = 40; i < 47; i += 2)

			add(new ImgComponent("images/white_sun.png").getImage(), i, "white", PIECE);

		for (int i = 49; i <= 55; i += 2)

			add(new ImgComponent("images/white_sun.png").getImage(), i, "white", PIECE);

		for (int i = 56; i < 63; i += 2)

			add(new ImgComponent("images/white_sun.png").getImage(), i, "white", PIECE);

	}

	/**

	 * The init method initializes a complete checkers board with figures and a

	 * history.

	 */

	public void init() {

		super.init();

		initBoard();

		board_pieces = getPieces();

		repaint();

	}

	public CheckersBoard(int w, int h) {

		super(w, h);

	}

	void add(Image img, int i, String c, int t) {

		int v = 0;

		switch (t) {

		case PIECE:

			v = 10;

		}

		setPiece(i, new Piece(img, c, t, v));

	}

	/**

	 * Checks, wether this move is possible or not.

	 */

	public boolean validMove(int t, int o) {

		int steps;

		int rows;

		if (t == o)

			return false;

		if (isSamePiece(t, o))

			return false;

		if (getType(o) == EMPTY)

			return false;

		/*

		 * 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22

		 * 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

		 * 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63

		 */

		steps = Math.abs(t - o);

		rows = Math.abs(t / 8 - o / 8);

		switch (getType(o)) {

		case PIECE:

			if (steps % 7 == 0) {

				if (steps == 7 && rows == 1 && isEmpty(t)) {

					if (isBlack(o) && (t > o))

						return true;

					if (isWhite(o) && (t < o))

						return true;

				}

				if (steps == 14 && rows == 2 && isEmpty(t)) {

					if (isBlack(o) && (t > o) && isEnemy(o + 7, o))

						return true;

					if (isWhite(o) && (t < o) && isEnemy(o - 7, o))

						return true;

				}

			}

			if (steps % 9 == 0) {

				if (steps == 9 && rows == 1 && isEmpty(t)) {

					if (isBlack(o) && (t > o))

						return true;

					if (isWhite(o) && (t < o))

						return true;

				}

				if (steps == 18 && rows == 2 && isEmpty(t)) {

					if (isBlack(o) && (t > o) && isEnemy(o + 9, o))

						return true;

					if (isWhite(o) && (t < o) && isEnemy(o - 9, o))

						return true;

				}

			}

			break;

		case QUEEN:

			if (steps % 7 == 0 && isEmpty(t)) {

				if (steps == 7 && rows == 1)

					return true;

				if (steps == 14 && rows == 2)

					return true;

				if (steps == 21 && rows == 3)

					return true;

				if (steps == 28 && rows == 4)

					return true;

				if (steps == 35 && rows == 5)

					return true;

				if (steps == 42 && rows == 6)

					return true;

				if (steps == 49 && rows == 7)

					return true;

			}

			if (steps % 9 == 0 && isEmpty(t)) {

				if (steps == 9 && rows == 1)

					return true;

				if (steps == 18 && rows == 2)

					return true;

				if (steps == 27 && rows == 3)

					return true;

				if (steps == 36 && rows == 4)

					return true;

				if (steps == 45 && rows == 5)

					return true;

				if (steps == 54 && rows == 6)

					return true;

				if (steps == 63 && rows == 7)

					return true;

			}

			break;

		}

		return false;

	}

	/**

	 * pop: undo the push operation.

	 */

	public void undo() {

		History h1 = null;

		History h2 = null;

		int size = stack.size();

		int pos;

		if (size < 2)

			return;

		h1 = stack.remove(size - 1);

		h2 = stack.remove(size - 2);

		setPiece(h1.pos(), h1.piece());

		setPiece(h2.pos(), h2.piece());

		if (getType(h2.pos()) != EMPTY) {

			pos = 2 * h2.pos() - h1.pos();

			if (pos >= 0 && pos < 64)

				setPiece(pos, new Piece(null, null, EMPTY, 0));

		}

		/* Reset the current player */

		setBlacksTurn(h2.turn());

	}

	/**

	 * simulates a "valid" move or returns false. all changes are relative to

	 * pieces and will not be painted.

	 */

	public boolean simulateMove(int t, int o) {

		int rows = Math.abs(t / 8 - o / 8);

		int pos;

		if (!validMove(t, o)) {

			return false;

		}

		if (rows == 2 && getType(o) == PIECE) {

			pos = (t - o) / 2 + o;

			push(getPiece(pos), pos, getPiece(o), o);

			setPiece(pos, new Piece(null, null, EMPTY, 0));

		} else

			push(getPiece(t), t, getPiece(o), o);

		setPiece(t, new Piece(getPiece(o)));

		setPiece(o, new Piece(null, null, EMPTY, 0));

		return true;

	}

	/**

	 * performs a "valid" move or returns false. all changes are relative to

	 * board_pieces and will be painted.

	 */

	public boolean doMove(int t, int o) {

		int steps = Math.abs(t - o);

		int rows = Math.abs(t / 8 - o / 8);

		int pos;

		if (!validMove(t, o)) {

			return false;

		}

		if (rows == 2 && getType(o) == PIECE) {

			pos = (t - o) / 2 + o;

			push(getPiece(pos), pos, getPiece(o), o);

			setPiece(pos, new Piece(null, null, EMPTY, 0));

		} else if (rows >= 2 && getType(o) == QUEEN) {

			if (steps % 7 == 0) {

				if (t > o)

					for (pos = o + 7; pos <= t - 7; pos += 7) {

						if (isEnemy(pos, o)) {

							push(getPiece(pos), pos, getPiece(o), o);

							setPiece(pos, new Piece(null, null, EMPTY, 0));

						}

					}

				else {

					for (pos = o - 7; pos >= t + 7; pos -= 7) {

						if (isEnemy(pos, o)) {

							push(getPiece(pos), pos, getPiece(o), o);

							setPiece(pos, new Piece(null, null, EMPTY, 0));

						}

					}

				}

			}

			if (steps % 9 == 0) {

				if (t > o)

					for (pos = o + 9; pos <= t - 9; pos += 9) {

						if (isEnemy(pos, o)) {

							push(getPiece(pos), pos, getPiece(o), o);

							setPiece(pos, new Piece(null, null, EMPTY, 0));

						}

					}

				else {

					for (pos = o - 9; pos >= t + 9; pos -= 9) {

						if (isEnemy(pos, o)) {

							push(getPiece(pos), pos, getPiece(o), o);

							setPiece(pos, new Piece(null, null, EMPTY, 0));

						}

					}

				}

			}

		}

		if (t <= 7 && getType(o) == PIECE)

			setPiece(t, new Piece(white_super_sun));

		else if (t >= 56 && getType(o) == PIECE)

			setPiece(t, new Piece(black_super_sun));

		else

			setPiece(t, new Piece(getPiece(o)));

		setPiece(o, new Piece(null, null, EMPTY, 0));

		board_pieces = getPieces();

		repaint();

		moveNr = stack.size();

		return true;

	}