[vchess.git] / public / javascripts / variants / Grand.js

// NOTE: initial setup differs from the original; see
// https://www.chessvariants.com/large.dir/freeling.html
class GrandRules extends ChessRules
{
	static getPpath(b)
	{
		return ([V.MARSHALL,V.CARDINAL].includes(b[1]) ? "Grand/" : "") + b;
	}

	static IsGoodFen(fen)
	{
		if (!ChessRules.IsGoodFen(fen))
			return false;
		const fenParsed = V.ParseFen(fen);
		// 5) Check captures
		if (!fenParsed.captured || !fenParsed.captured.match(/^[0-9]{10,10}$/))
			return false;
		return true;
	}

	static ParseFen(fen)
	{
		const fenParts = fen.split(" ");
		return Object.assign(
			ChessRules.ParseFen(fen),
			{ captured: fenParts[4] }
		);
	}

	getFen()
	{
		return super.getFen() + " " + this.getCapturedFen();
	}

	getCapturedFen()
	{
		let counts = _.map(_.range(10), 0);
		for (let i=0; i<V.PIECES.length-1; i++) //-1: no king captured
		{
			counts[i] = this.captured["w"][V.PIECES[i]];
			counts[5+i] = this.captured["b"][V.PIECES[i]];
		}
		return counts.join("");
	}

	setOtherVariables(fen)
	{
		super.setOtherVariables(fen);
		const fenParsed = V.ParseFen(fen);
		// Initialize captured pieces' counts from FEN
		this.captured =
		{
			"w":
			{
				[V.PAWN]: parseInt(fenParsed.captured[0]),
				[V.ROOK]: parseInt(fenParsed.captured[1]),
				[V.KNIGHT]: parseInt(fenParsed.captured[2]),
				[V.BISHOP]: parseInt(fenParsed.captured[3]),
				[V.QUEEN]: parseInt(fenParsed.captured[4]),
			},
			"b":
			{
				[V.PAWN]: parseInt(fenParsed.captured[5]),
				[V.ROOK]: parseInt(fenParsed.captured[6]),
				[V.KNIGHT]: parseInt(fenParsed.captured[7]),
				[V.BISHOP]: parseInt(fenParsed.captured[8]),
				[V.QUEEN]: parseInt(fenParsed.captured[9]),
			}
		};
	}

	static get size() { return {x:10,y:10}; }

	static get MARSHALL() { return 'm'; } //rook+knight
	static get CARDINAL() { return 'c'; } //bishop+knight

	static get PIECES()
	{
		return ChessRules.PIECES.concat([V.MARSHALL,V.CARDINAL]);
	}

	// There may be 2 enPassant squares (if pawn jump 3 squares)
	getEnpassantFen()
	{
		const L = this.epSquares.length;
		if (!this.epSquares[L-1])
			return "-"; //no en-passant
		let res = "";
		this.epSquares[L-1].forEach(sq => {
			res += V.CoordsToSquare(sq) + ",";
		});
		return res.slice(0,-1); //remove last comma
	}

	// En-passant after 2-sq or 3-sq jumps
	getEpSquare(moveOrSquare)
	{
		if (!moveOrSquare)
			return undefined;
		if (typeof moveOrSquare === "string")
		{
			const square = moveOrSquare;
			if (square == "-")
				return undefined;
			let res = [];
			square.split(",").forEach(sq => {
				res.push(V.SquareToCoords(sq));
			});
			return res;
		}
		// Argument is a move:
		const move = moveOrSquare;
		const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x];
		if (this.getPiece(sx,sy) == V.PAWN && Math.abs(sx - ex) >= 2)
		{
			const step = (ex-sx) / Math.abs(ex-sx);
			let res = [{
				x: sx + step,
				y: sy
			}];
			if (sx + 2*step != ex) //3-squares move
			{
				res.push({
					x: sx + 2*step,
					y: sy
				});
			}
			return res;
		}
		return undefined; //default
	}

	getPotentialMovesFrom([x,y])
	{
		switch (this.getPiece(x,y))
		{
			case V.MARSHALL:
				return this.getPotentialMarshallMoves([x,y]);
			case V.CARDINAL:
				return this.getPotentialCardinalMoves([x,y]);
			default:
				return super.getPotentialMovesFrom([x,y])
		}
	}

	// Special pawn rules: promotions to captured friendly pieces,
	// optional on ranks 8-9 and mandatory on rank 10.
	getPotentialPawnMoves([x,y])
	{
		const color = this.turn;
		let moves = [];
		const [sizeX,sizeY] = [V.size.x,V.size.y];
		const shift = (color == "w" ? -1 : 1);
		const startRanks = (color == "w" ? [sizeX-2,sizeX-3] : [1,2]);
		const lastRanks = (color == "w" ? [0,1,2] : [sizeX-1,sizeX-2,sizeX-3]);

		if (x+shift >= 0 && x+shift < sizeX && x+shift != lastRanks[0])
		{
			// Normal moves
			if (this.board[x+shift][y] == V.EMPTY)
			{
				moves.push(this.getBasicMove([x,y], [x+shift,y]));
				if (startRanks.includes(x) && this.board[x+2*shift][y] == V.EMPTY)
				{
					// Two squares jump
					moves.push(this.getBasicMove([x,y], [x+2*shift,y]));
					if (x == startRanks[0] && this.board[x+3*shift][y] == V.EMPTY)
					{
						// 3-squares jump
						moves.push(this.getBasicMove([x,y], [x+3*shift,y]));
					}
				}
			}
			// Captures
			if (y>0 && this.canTake([x,y], [x+shift,y-1])
				&& this.board[x+shift][y-1] != V.EMPTY)
			{
				moves.push(this.getBasicMove([x,y], [x+shift,y-1]));
			}
			if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1])
				&& this.board[x+shift][y+1] != V.EMPTY)
			{
				moves.push(this.getBasicMove([x,y], [x+shift,y+1]));
			}
		}

		if (lastRanks.includes(x+shift))
		{
			// Promotion
			let promotionPieces = [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN,V.MARSHALL,V.CARDINAL];
			promotionPieces.forEach(p => {
				if (this.captured[color][p]==0)
					return;
				// Normal move
				if (this.board[x+shift][y] == V.EMPTY)
					moves.push(this.getBasicMove([x,y], [x+shift,y], {c:color,p:p}));
				// Captures
				if (y>0 && this.canTake([x,y], [x+shift,y-1])
					&& this.board[x+shift][y-1] != V.EMPTY)
				{
					moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:color,p:p}));
				}
				if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1])
					&& this.board[x+shift][y+1] != V.EMPTY)
				{
					moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:color,p:p}));
				}
			});
		}

		// En passant
		const Lep = this.epSquares.length;
		const epSquare = Lep>0 ? this.epSquares[Lep-1] : undefined;
		if (!!epSquare)
		{
			for (let epsq of epSquare)
			{
				// TODO: some redundant checks
				if (epsq.x == x+shift && Math.abs(epsq.y - y) == 1)
				{
					var enpassantMove = this.getBasicMove([x,y], [x+shift,epsq.y]);
					enpassantMove.vanish.push({
						x: x,
						y: epsq.y,
						p: 'p',
						c: this.getColor(x,epsq.y)
					});
					moves.push(enpassantMove);
				}
			}
		}

		return moves;
	}

	// TODO: different castle?

	getPotentialMarshallMoves(sq)
	{
		return this.getSlideNJumpMoves(sq, V.steps[V.ROOK]).concat(
			this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep"));
	}

	getPotentialCardinalMoves(sq)
	{
		return this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]).concat(
			this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep"));
	}

	isAttacked(sq, colors)
	{
		return super.isAttacked(sq, colors)
			|| this.isAttackedByMarshall(sq, colors)
			|| this.isAttackedByCardinal(sq, colors);
	}

	isAttackedByMarshall(sq, colors)
	{
		return this.isAttackedBySlideNJump(sq, colors, V.MARSHALL, V.steps[V.ROOK])
			|| this.isAttackedBySlideNJump(
				sq, colors, V.MARSHALL, V.steps[V.KNIGHT], "oneStep");
	}

	isAttackedByCardinal(sq, colors)
	{
		return this.isAttackedBySlideNJump(sq, colors, V.CARDINAL, V.steps[V.BISHOP])
			|| this.isAttackedBySlideNJump(
				sq, colors, V.CARDINAL, V.steps[V.KNIGHT], "oneStep");
	}

	updateVariables(move)
	{
		super.updateVariables(move);
		if (move.vanish.length==2 && move.appear.length==1 && move.vanish[1].p != V.PAWN)
		{
			// Capture: update this.captured
			this.captured[move.vanish[1].c][move.vanish[1].p]++;
		}
	}

	unupdateVariables(move)
	{
		super.unupdateVariables(move);
		if (move.vanish.length==2 && move.appear.length==1 && move.vanish[1].p != V.PAWN)
			this.captured[move.vanish[1].c][move.vanish[1].p]--;
	}

	static get VALUES()
	{
		return Object.assign(
			ChessRules.VALUES,
			{'c': 5, 'm': 7} //experimental
		);
	}

	static get SEARCH_DEPTH() { return 2; }

	// TODO: this function could be generalized and shared better (how ?!...)
	static GenRandInitFen()
	{
		let pieces = { "w": new Array(10), "b": new Array(10) };
		// Shuffle pieces on first and last rank
		for (let c of ["w","b"])
		{
			let positions = _.range(10);

			// Get random squares for bishops
			let randIndex = 2 * _.random(4);
			let bishop1Pos = positions[randIndex];
			// The second bishop must be on a square of different color
			let randIndex_tmp = 2 * _.random(4) + 1;
			let bishop2Pos = positions[randIndex_tmp];
			// Remove chosen squares
			positions.splice(Math.max(randIndex,randIndex_tmp), 1);
			positions.splice(Math.min(randIndex,randIndex_tmp), 1);

			// Get random squares for knights
			randIndex = _.random(7);
			let knight1Pos = positions[randIndex];
			positions.splice(randIndex, 1);
			randIndex = _.random(6);
			let knight2Pos = positions[randIndex];
			positions.splice(randIndex, 1);

			// Get random square for queen
			randIndex = _.random(5);
			let queenPos = positions[randIndex];
			positions.splice(randIndex, 1);

			// ...random square for marshall
			randIndex = _.random(4);
			let marshallPos = positions[randIndex];
			positions.splice(randIndex, 1);

			// ...random square for cardinal
			randIndex = _.random(3);
			let cardinalPos = positions[randIndex];
			positions.splice(randIndex, 1);

			// Rooks and king positions are now fixed, because of the ordering rook-king-rook
			let rook1Pos = positions[0];
			let kingPos = positions[1];
			let rook2Pos = positions[2];

			// Finally put the shuffled pieces in the board array
			pieces[c][rook1Pos] = 'r';
			pieces[c][knight1Pos] = 'n';
			pieces[c][bishop1Pos] = 'b';
			pieces[c][queenPos] = 'q';
			pieces[c][marshallPos] = 'm';
			pieces[c][cardinalPos] = 'c';
			pieces[c][kingPos] = 'k';
			pieces[c][bishop2Pos] = 'b';
			pieces[c][knight2Pos] = 'n';
			pieces[c][rook2Pos] = 'r';
		}
		return pieces["b"].join("") +
			"/pppppppppp/10/10/10/10/10/10/PPPPPPPPPP/" +
			pieces["w"].join("").toUpperCase() +
			" w 1111 - 0000000000";
	}
}

const VariantRules = GrandRules;
Commit	Line	Data
92342261 BA	1	// NOTE: initial setup differs from the original; see
92342261 BA	2	// https://www.chessvariants.com/large.dir/freeling.html
a37076f1 BA	3	class GrandRules extends ChessRules
	4	{
	5	static getPpath(b)
	6	{
c6052161	7	return ([V.MARSHALL,V.CARDINAL].includes(b[1]) ? "Grand/" : "") + b;
a37076f1 BA	8	}
a37076f1 BA	9
2d7194bd	10	static IsGoodFen(fen)
c6052161	11	{
2d7194bd BA	12	if (!ChessRules.IsGoodFen(fen))
	13	return false;
	14	const fenParsed = V.ParseFen(fen);
	15	// 5) Check captures
	16	if (!fenParsed.captured \|\| !fenParsed.captured.match(/^[0-9]{10,10}$/))
	17	return false;
	18	return true;
	19	}
	20
fb6ceeff BA	21	static ParseFen(fen)
	22	{
	23	const fenParts = fen.split(" ");
	24	return Object.assign(
	25	ChessRules.ParseFen(fen),
	26	{ captured: fenParts[4] }
	27	);
	28	}
	29
2d7194bd BA	30	getFen()
	31	{
	32	return super.getFen() + " " + this.getCapturedFen();
	33	}
	34
	35	getCapturedFen()
	36	{
	37	let counts = _.map(_.range(10), 0);
dc0d28e5	38	for (let i=0; i<V.PIECES.length-1; i++) //-1: no king captured
2d7194bd BA	39	{
	40	counts[i] = this.captured["w"][V.PIECES[i]];
	41	counts[5+i] = this.captured["b"][V.PIECES[i]];
	42	}
	43	return counts.join("");
	44	}
	45
	46	setOtherVariables(fen)
	47	{
	48	super.setOtherVariables(fen);
	49	const fenParsed = V.ParseFen(fen);
	50	// Initialize captured pieces' counts from FEN
	51	this.captured =
	52	{
	53	"w":
	54	{
	55	[V.PAWN]: parseInt(fenParsed.captured[0]),
	56	[V.ROOK]: parseInt(fenParsed.captured[1]),
	57	[V.KNIGHT]: parseInt(fenParsed.captured[2]),
	58	[V.BISHOP]: parseInt(fenParsed.captured[3]),
	59	[V.QUEEN]: parseInt(fenParsed.captured[4]),
	60	},
	61	"b":
	62	{
	63	[V.PAWN]: parseInt(fenParsed.captured[5]),
	64	[V.ROOK]: parseInt(fenParsed.captured[6]),
	65	[V.KNIGHT]: parseInt(fenParsed.captured[7]),
	66	[V.BISHOP]: parseInt(fenParsed.captured[8]),
	67	[V.QUEEN]: parseInt(fenParsed.captured[9]),
	68	}
	69	};
c6052161 BA	70	}
c6052161 BA	71
0b7d99ec	72	static get size() { return {x:10,y:10}; }
c6052161	73
a37076f1 BA	74	static get MARSHALL() { return 'm'; } //rook+knight
	75	static get CARDINAL() { return 'c'; } //bishop+knight
	76
2d7194bd BA	77	static get PIECES()
2d7194bd BA	78	{
7931e479 BA	79	return ChessRules.PIECES.concat([V.MARSHALL,V.CARDINAL]);
	80	}
	81
2d7194bd BA	82	// There may be 2 enPassant squares (if pawn jump 3 squares)
	83	getEnpassantFen()
	84	{
	85	const L = this.epSquares.length;
	86	if (!this.epSquares[L-1])
	87	return "-"; //no en-passant
	88	let res = "";
	89	this.epSquares[L-1].forEach(sq => {
	90	res += V.CoordsToSquare(sq) + ",";
	91	});
	92	return res.slice(0,-1); //remove last comma
	93	}
	94
c6052161	95	// En-passant after 2-sq or 3-sq jumps
2d7194bd	96	getEpSquare(moveOrSquare)
a37076f1	97	{
2d7194bd BA	98	if (!moveOrSquare)
	99	return undefined;
	100	if (typeof moveOrSquare === "string")
	101	{
	102	const square = moveOrSquare;
	103	if (square == "-")
	104	return undefined;
	105	let res = [];
	106	square.split(",").forEach(sq => {
	107	res.push(V.SquareToCoords(sq));
	108	});
	109	return res;
	110	}
	111	// Argument is a move:
	112	const move = moveOrSquare;
a37076f1	113	const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x];
0b7d99ec	114	if (this.getPiece(sx,sy) == V.PAWN && Math.abs(sx - ex) >= 2)
a37076f1	115	{
c6052161 BA	116	const step = (ex-sx) / Math.abs(ex-sx);
	117	let res = [{
	118	x: sx + step,
a37076f1	119	y: sy
c6052161 BA	120	}];
	121	if (sx + 2*step != ex) //3-squares move
	122	{
	123	res.push({
	124	x: sx + 2*step,
	125	y: sy
	126	});
	127	}
	128	return res;
a37076f1 BA	129	}
	130	return undefined; //default
	131	}
	132
	133	getPotentialMovesFrom([x,y])
	134	{
	135	switch (this.getPiece(x,y))
	136	{
0b7d99ec	137	case V.MARSHALL:
a37076f1	138	return this.getPotentialMarshallMoves([x,y]);
0b7d99ec	139	case V.CARDINAL:
a37076f1 BA	140	return this.getPotentialCardinalMoves([x,y]);
	141	default:
	142	return super.getPotentialMovesFrom([x,y])
	143	}
	144	}
	145
c6052161 BA	146	// Special pawn rules: promotions to captured friendly pieces,
c6052161 BA	147	// optional on ranks 8-9 and mandatory on rank 10.
a37076f1 BA	148	getPotentialPawnMoves([x,y])
a37076f1 BA	149	{
c6052161 BA	150	const color = this.turn;
c6052161 BA	151	let moves = [];
0b7d99ec	152	const [sizeX,sizeY] = [V.size.x,V.size.y];
c6052161	153	const shift = (color == "w" ? -1 : 1);
cf130369 BA	154	const startRanks = (color == "w" ? [sizeX-2,sizeX-3] : [1,2]);
cf130369 BA	155	const lastRanks = (color == "w" ? [0,1,2] : [sizeX-1,sizeX-2,sizeX-3]);
c6052161 BA	156
	157	if (x+shift >= 0 && x+shift < sizeX && x+shift != lastRanks[0])
	158	{
	159	// Normal moves
	160	if (this.board[x+shift][y] == V.EMPTY)
	161	{
	162	moves.push(this.getBasicMove([x,y], [x+shift,y]));
	163	if (startRanks.includes(x) && this.board[x+2*shift][y] == V.EMPTY)
	164	{
	165	// Two squares jump
	166	moves.push(this.getBasicMove([x,y], [x+2*shift,y]));
8a196305	167	if (x == startRanks[0] && this.board[x+3*shift][y] == V.EMPTY)
c6052161 BA	168	{
	169	// 3-squares jump
	170	moves.push(this.getBasicMove([x,y], [x+3*shift,y]));
	171	}
	172	}
	173	}
	174	// Captures
92342261 BA	175	if (y>0 && this.canTake([x,y], [x+shift,y-1])
	176	&& this.board[x+shift][y-1] != V.EMPTY)
	177	{
c6052161	178	moves.push(this.getBasicMove([x,y], [x+shift,y-1]));
92342261 BA	179	}
	180	if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1])
	181	&& this.board[x+shift][y+1] != V.EMPTY)
	182	{
c6052161	183	moves.push(this.getBasicMove([x,y], [x+shift,y+1]));
92342261	184	}
c6052161 BA	185	}
	186
	187	if (lastRanks.includes(x+shift))
	188	{
	189	// Promotion
8a196305	190	let promotionPieces = [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN,V.MARSHALL,V.CARDINAL];
c6052161	191	promotionPieces.forEach(p => {
2d7194bd	192	if (this.captured[color][p]==0)
c6052161 BA	193	return;
	194	// Normal move
	195	if (this.board[x+shift][y] == V.EMPTY)
	196	moves.push(this.getBasicMove([x,y], [x+shift,y], {c:color,p:p}));
	197	// Captures
92342261 BA	198	if (y>0 && this.canTake([x,y], [x+shift,y-1])
	199	&& this.board[x+shift][y-1] != V.EMPTY)
	200	{
c6052161	201	moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:color,p:p}));
92342261 BA	202	}
	203	if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1])
	204	&& this.board[x+shift][y+1] != V.EMPTY)
	205	{
c6052161	206	moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:color,p:p}));
92342261	207	}
c6052161 BA	208	});
	209	}
	210
	211	// En passant
	212	const Lep = this.epSquares.length;
	213	const epSquare = Lep>0 ? this.epSquares[Lep-1] : undefined;
	214	if (!!epSquare)
	215	{
	216	for (let epsq of epSquare)
	217	{
	218	// TODO: some redundant checks
	219	if (epsq.x == x+shift && Math.abs(epsq.y - y) == 1)
	220	{
375ecdd1	221	var enpassantMove = this.getBasicMove([x,y], [x+shift,epsq.y]);
c6052161 BA	222	enpassantMove.vanish.push({
c6052161 BA	223	x: x,
375ecdd1	224	y: epsq.y,
c6052161	225	p: 'p',
375ecdd1	226	c: this.getColor(x,epsq.y)
c6052161 BA	227	});
	228	moves.push(enpassantMove);
	229	}
	230	}
	231	}
	232
	233	return moves;
a37076f1 BA	234	}
a37076f1 BA	235
8a196305 BA	236	// TODO: different castle?
8a196305 BA	237
a37076f1 BA	238	getPotentialMarshallMoves(sq)
a37076f1 BA	239	{
a37076f1 BA	240	return this.getSlideNJumpMoves(sq, V.steps[V.ROOK]).concat(
	241	this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep"));
	242	}
	243
	244	getPotentialCardinalMoves(sq)
	245	{
a37076f1 BA	246	return this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]).concat(
	247	this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep"));
	248	}
	249
	250	isAttacked(sq, colors)
	251	{
c6052161	252	return super.isAttacked(sq, colors)
a37076f1 BA	253	\|\| this.isAttackedByMarshall(sq, colors)
	254	\|\| this.isAttackedByCardinal(sq, colors);
	255	}
	256
	257	isAttackedByMarshall(sq, colors)
	258	{
a37076f1	259	return this.isAttackedBySlideNJump(sq, colors, V.MARSHALL, V.steps[V.ROOK])
92342261 BA	260	\|\| this.isAttackedBySlideNJump(
92342261 BA	261	sq, colors, V.MARSHALL, V.steps[V.KNIGHT], "oneStep");
a37076f1 BA	262	}
	263
	264	isAttackedByCardinal(sq, colors)
	265	{
a37076f1	266	return this.isAttackedBySlideNJump(sq, colors, V.CARDINAL, V.steps[V.BISHOP])
92342261 BA	267	\|\| this.isAttackedBySlideNJump(
92342261 BA	268	sq, colors, V.CARDINAL, V.steps[V.KNIGHT], "oneStep");
a37076f1 BA	269	}
a37076f1 BA	270
a6abf094	271	updateVariables(move)
c6052161	272	{
a6abf094	273	super.updateVariables(move);
0b7d99ec	274	if (move.vanish.length==2 && move.appear.length==1 && move.vanish[1].p != V.PAWN)
c6052161	275	{
2d7194bd BA	276	// Capture: update this.captured
2d7194bd BA	277	this.captured[move.vanish[1].c][move.vanish[1].p]++;
c6052161 BA	278	}
	279	}
	280
a6abf094	281	unupdateVariables(move)
c6052161	282	{
a6abf094	283	super.unupdateVariables(move);
0b7d99ec	284	if (move.vanish.length==2 && move.appear.length==1 && move.vanish[1].p != V.PAWN)
2d7194bd	285	this.captured[move.vanish[1].c][move.vanish[1].p]--;
c6052161 BA	286	}
c6052161 BA	287
2d7194bd BA	288	static get VALUES()
2d7194bd BA	289	{
a37076f1 BA	290	return Object.assign(
	291	ChessRules.VALUES,
	292	{'c': 5, 'm': 7} //experimental
	293	);
	294	}
	295
3c09dc49 BA	296	static get SEARCH_DEPTH() { return 2; }
3c09dc49 BA	297
2d7194bd	298	// TODO: this function could be generalized and shared better (how ?!...)
a37076f1 BA	299	static GenRandInitFen()
a37076f1 BA	300	{
92342261	301	let pieces = { "w": new Array(10), "b": new Array(10) };
c6052161	302	// Shuffle pieces on first and last rank
92342261	303	for (let c of ["w","b"])
c6052161 BA	304	{
	305	let positions = _.range(10);
	306
	307	// Get random squares for bishops
	308	let randIndex = 2 * _.random(4);
	309	let bishop1Pos = positions[randIndex];
	310	// The second bishop must be on a square of different color
	311	let randIndex_tmp = 2 * _.random(4) + 1;
	312	let bishop2Pos = positions[randIndex_tmp];
	313	// Remove chosen squares
	314	positions.splice(Math.max(randIndex,randIndex_tmp), 1);
	315	positions.splice(Math.min(randIndex,randIndex_tmp), 1);
	316
	317	// Get random squares for knights
	318	randIndex = _.random(7);
	319	let knight1Pos = positions[randIndex];
	320	positions.splice(randIndex, 1);
	321	randIndex = _.random(6);
	322	let knight2Pos = positions[randIndex];
	323	positions.splice(randIndex, 1);
	324
	325	// Get random square for queen
	326	randIndex = _.random(5);
	327	let queenPos = positions[randIndex];
	328	positions.splice(randIndex, 1);
	329
	330	// ...random square for marshall
	331	randIndex = _.random(4);
	332	let marshallPos = positions[randIndex];
	333	positions.splice(randIndex, 1);
	334
	335	// ...random square for cardinal
	336	randIndex = _.random(3);
	337	let cardinalPos = positions[randIndex];
	338	positions.splice(randIndex, 1);
	339
	340	// Rooks and king positions are now fixed, because of the ordering rook-king-rook
	341	let rook1Pos = positions[0];
	342	let kingPos = positions[1];
	343	let rook2Pos = positions[2];
	344
	345	// Finally put the shuffled pieces in the board array
	346	pieces[c][rook1Pos] = 'r';
	347	pieces[c][knight1Pos] = 'n';
	348	pieces[c][bishop1Pos] = 'b';
	349	pieces[c][queenPos] = 'q';
	350	pieces[c][marshallPos] = 'm';
	351	pieces[c][cardinalPos] = 'c';
	352	pieces[c][kingPos] = 'k';
	353	pieces[c][bishop2Pos] = 'b';
	354	pieces[c][knight2Pos] = 'n';
	355	pieces[c][rook2Pos] = 'r';
	356	}
c794dbb8	357	return pieces["b"].join("") +
c6052161	358	"/pppppppppp/10/10/10/10/10/10/PPPPPPPPPP/" +
92342261	359	pieces["w"].join("").toUpperCase() +
d7f69b87	360	" w 1111 - 0000000000";
a37076f1 BA	361	}
a37076f1 BA	362	}
643479f8 BA	363
643479f8 BA	364	const VariantRules = GrandRules;