package chess.model;

/**
 * Enumation of the different directions from a cell in a chessboard, and how to navigate the cells.
 */

public enum Direction {

	Unset(65),
	Front(-8), Back(8), Left(-1), Right(1),
	FrontLeft(-9), FrontRight(-7), BackLeft(7), BackRight(9);

	private final int indexOffset;

	Direction(int indexOffset) {
		this.indexOffset = indexOffset;
	}

	public int getIndexOffset() {
		return indexOffset;
	}

	public static Direction fromInt(int direction) {
		for (Direction dir : Direction.values()) {
			if (dir.getIndexOffset() == direction)
				return dir;
		}
		return null;
	}

	public static Direction findDirection(Move move) {
		assert move.isValid() : "Move is invalid!";
		int diffX = move.getFinish().getX() - move.getStart().getX();
		int diffY = move.getFinish().getY() - move.getStart().getY();

		if (diffX == 0 && diffY < 0)
			return Direction.Front;
		if (diffX == 0 && diffY > 0)
			return Direction.Back;

		if (diffX < 0 && diffY == 0)
			return Direction.Left;
		if (diffX > 0 && diffY == 0)
			return Direction.Right;

		if (diffX < 0 && -diffX == diffY)
			return Direction.BackLeft;
		if (diffX > 0 && diffX == diffY)
			return Direction.BackRight;

		if (diffY < 0 && diffX == diffY)
			return Direction.FrontLeft;
		if (diffX > 0 && diffX == -diffY)
			return Direction.FrontRight;

		return Direction.Unset;
	}
}