var PIECES =  { EMPTY : 0, wP : 1, wN : 2, wB : 3,wR : 4, wQ : 5, wK : 6, 
              bP : 7, bN : 8, bB : 9, bR : 10, bQ : 11, bK : 12  };
              
var BRD_SQ_NUM = 120;

var FILES =  { FILE_A:0, FILE_B:1, FILE_C:2, FILE_D:3, 
	FILE_E:4, FILE_F:5, FILE_G:6, FILE_H:7, FILE_NONE:8 };
	
var RANKS =  { RANK_1:0, RANK_2:1, RANK_3:2, RANK_4:3, 
	RANK_5:4, RANK_6:5, RANK_7:6, RANK_8:7, RANK_NONE:8 };
	
var COLOURS = { WHITE:0, BLACK:1, BOTH:2 };

var CASTLEBIT = { WKCA : 1, WQCA : 2, BKCA : 4, BQCA : 8 };

var SQUARES = {
  A1:21, B1:22, C1:23, D1:24, E1:25, F1:26, G1:27, H1:28,  
  A8:91, B8:92, C8:93, D8:94, E8:95, F8:96, G8:97, H8:98, 
  NO_SQ:99, OFFBOARD:100
};

var BOOL = { FALSE:0, TRUE:1 };

var MAXGAMEMOVES = 2048;
var MAXPOSITIONMOVES = 256;
var MAXDEPTH = 64;
var INFINITE = 30000;
var MATE = 29000;
var PVENTRIES = 10000;

var FilesBrd = new Array(BRD_SQ_NUM);
var RanksBrd = new Array(BRD_SQ_NUM);

var START_FEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";

var PceChar = ".PNBRQKpnbrqk";
var SideChar = "wb-";
var RankChar = "12345678";
var FileChar = "abcdefgh";

function FR2SQ(f,r) {
 	return ( (21 + (f) ) + ( (r) * 10 ) );
}

var PieceBig = [ BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE ];
var PieceMaj = [ BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE ];
var PieceMin = [ BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE ];
var PieceVal= [ 0, 100, 325, 325, 550, 1000, 50000, 100, 325, 325, 550, 1000, 50000  ];
var PieceCol = [ COLOURS.BOTH, COLOURS.WHITE, COLOURS.WHITE, COLOURS.WHITE, COLOURS.WHITE, COLOURS.WHITE, COLOURS.WHITE,
	COLOURS.BLACK, COLOURS.BLACK, COLOURS.BLACK, COLOURS.BLACK, COLOURS.BLACK, COLOURS.BLACK ];
	
var PiecePawn = [ BOOL.FALSE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE ];	
var PieceKnight = [ BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE ];
var PieceKing = [ BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE ];
var PieceRookQueen = [ BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.FALSE ];
var PieceBishopQueen = [ BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.FALSE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.FALSE, BOOL.TRUE, BOOL.FALSE ];
var PieceSlides = [ BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE, BOOL.FALSE, BOOL.FALSE, BOOL.FALSE, BOOL.TRUE, BOOL.TRUE, BOOL.TRUE, BOOL.FALSE ];

var KnDir = [ -8, -19,	-21, -12, 8, 19, 21, 12 ];
var RkDir = [ -1, -10,	1, 10 ];
var BiDir = [ -9, -11, 11, 9 ];
var KiDir = [ -1, -10,	1, 10, -9, -11, 11, 9 ];

var DirNum = [ 0, 0, 8, 4, 4, 8, 8, 0, 8, 4, 4, 8, 8 ];
var PceDir = [ 0, 0, KnDir, BiDir, RkDir, KiDir, KiDir, 0, KnDir, BiDir, RkDir, KiDir, KiDir ];
var LoopNonSlidePce = [ PIECES.wN, PIECES.wK, 0, PIECES.bN, PIECES.bK, 0 ];
var LoopNonSlideIndex = [ 0, 3 ];
var LoopSlidePce = [ PIECES.wB, PIECES.wR, PIECES.wQ, 0, PIECES.bB, PIECES.bR, PIECES.bQ, 0 ];
var LoopSlideIndex = [ 0, 4];

var PieceKeys = new Array(14 * 120);
var SideKey;
var CastleKeys = new Array(16);

var Sq120ToSq64 = new Array(BRD_SQ_NUM);
var Sq64ToSq120 = new Array(64);

function RAND_32() {

	return (Math.floor((Math.random()*255)+1) << 23) | (Math.floor((Math.random()*255)+1) << 16)
		 | (Math.floor((Math.random()*255)+1) << 8) | Math.floor((Math.random()*255)+1);

}

var Mirror64 = [
56	,	57	,	58	,	59	,	60	,	61	,	62	,	63	,
48	,	49	,	50	,	51	,	52	,	53	,	54	,	55	,
40	,	41	,	42	,	43	,	44	,	45	,	46	,	47	,
32	,	33	,	34	,	35	,	36	,	37	,	38	,	39	,
24	,	25	,	26	,	27	,	28	,	29	,	30	,	31	,
16	,	17	,	18	,	19	,	20	,	21	,	22	,	23	,
8	,	9	,	10	,	11	,	12	,	13	,	14	,	15	,
0	,	1	,	2	,	3	,	4	,	5	,	6	,	7
];

function SQ64(sq120) { 
	return Sq120ToSq64[(sq120)];
}

function SQ120(sq64) {
	return Sq64ToSq120[(sq64)];
}

function PCEINDEX(pce, pceNum) {
	return (pce * 10 + pceNum);
}

function MIRROR64(sq) {
	return Mirror64[sq];
}

var Kings = [PIECES.wK, PIECES.bK];
var CastlePerm = [
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
    15, 13, 15, 15, 15, 12, 15, 15, 14, 15,
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
    15,  7, 15, 15, 15,  3, 15, 15, 11, 15,
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
    15, 15, 15, 15, 15, 15, 15, 15, 15, 15
];

/*	
0000 0000 0000 0000 0000 0111 1111 -> From 0x7F
0000 0000 0000 0011 1111 1000 0000 -> To >> 7, 0x7F
0000 0000 0011 1100 0000 0000 0000 -> Captured >> 14, 0xF
0000 0000 0100 0000 0000 0000 0000 -> EP 0x40000
0000 0000 1000 0000 0000 0000 0000 -> Pawn Start 0x80000
0000 1111 0000 0000 0000 0000 0000 -> Promoted Piece >> 20, 0xF
0001 0000 0000 0000 0000 0000 0000 -> Castle 0x1000000
*/


function FROMSQ(m) { return (m & 0x7F); }
function TOSQ(m) { return ( (m >> 7) & 0x7F); }
function CAPTURED(m) { return ( (m >> 14) & 0xF); }
function PROMOTED(m) { return ( (m >> 20) & 0xF); }

var MFLAGEP = 0x40000;
var MFLAGPS = 0x80000;
var MFLAGCA = 0x1000000;

var MFLAGCAP = 0x7C000;
var MFLAGPROM = 0xF00000;

var NOMOVE = 0;

function SQOFFBOARD(sq) {
	if(FilesBrd[sq]==SQUARES.OFFBOARD) return BOOL.TRUE;
	return BOOL.FALSE;	
}

function HASH_PCE(pce, sq) {
	GameBoard.posKey ^= PieceKeys[(pce * 120) + sq];
}

function HASH_CA() { GameBoard.posKey ^= CastleKeys[GameBoard.castlePerm]; }
function HASH_SIDE() { GameBoard.posKey ^= SideKey; }
function HASH_EP() { GameBoard.posKey ^= PieceKeys[GameBoard.enPas]; }

var GameController = {};
GameController.EngineSide = COLOURS.BOTH;
GameController.PlayerSide = COLOURS.BOTH;
GameController.GameOver = BOOL.FALSE;

var UserMove = {};
UserMove.from = SQUARES.NO_SQ;
UserMove.to = SQUARES.NO_SQ;