/**
 * A representation of a tile type by the directions of the possible connections
 * to other tiles.
 * 
 * @author Felix Reidl
 */
public enum TileType {
    // Read: right is the LSB!

    BLANK("0000"),
    LR("0101"), TB("1010"), LT("0011"), TR("0110"), RB("1100"), LB("1001"), // 2-tiles
    LTR("0111"), TRB("1110"), LRB("1101"), LTB("1011"), // 3-tiles
    LTRB("1111"); // 4-tile
    private final byte mask;

    TileType(String mask) {
	this.mask = Byte.parseByte(mask, 2);
    }

    public static TileType fromByte(byte mask) {
	TileType[] tiles = TileType.values();
	for (int i = 0; i < tiles.length; i++) {
	    if (tiles[i].mask == mask) {
		return tiles[i];
	    }
	}

	throw new RuntimeException("Invalid tile mask '" 
		+ Integer.toBinaryString(mask) + "' (" + mask + ")");
    }
    
    public static boolean isBlank(TileType type) {
        return type == BLANK;
    }
    
    public static boolean isCurve(TileType type) {
        return type == LT || type == TR || type == RB || type == LB;
    }
    
    public static boolean isStraight(TileType type) {
        return type == TB || type == LR;
    }
    
    public static boolean isTee(TileType type) {
        return type == LTR || type == TRB || type == LRB || type == LTB;
    }
    
    public static boolean isCross(TileType type) {
        return type == LTRB;
    }

    /**
     * The byte representation of the tile has for relevant position. If a
     * bit is set to 1, it means that the tile has a connection in that 
     * direction. From left to right the positions mean: Left, Top, Right and
     * Bottom, i.e. clockwise starting left.
     * @return A byte representation of the tile.
     */
    public byte toByte() {
	return mask;
    }
}