X-Git-Url: https://git.auder.net/?p=vchess.git;a=blobdiff_plain;f=public%2Fjavascripts%2Fbase_rules.js;h=9599fdbf4534b8dd5d748ef660d6874ed1daf9e4;hp=620b86f85b129d61078c877910bbac2660513271;hb=69f3d8014e594ef949792d04d97b8286e9c2c268;hpb=1a788978e3682ab54b77af3edfe38e0b371edbc4

diff --git a/public/javascripts/base_rules.js b/public/javascripts/base_rules.js
index 620b86f8..9599fdbf 100644
--- a/public/javascripts/base_rules.js
+++ b/public/javascripts/base_rules.js
@@ -34,6 +34,10 @@ class ChessRules
 	//////////////
 	// MISC UTILS
 
+	static get HasFlags() { return true; } //some variants don't have flags
+
+	static get HasEnpassant() { return true; } //some variants don't have ep.
+
 	// Path to pieces
 	static getPpath(b)
 	{
@@ -57,7 +61,28 @@ class ChessRules
 	{
 		const fenParsed = V.ParseFen(fen);
 		// 1) Check position
-		const position = fenParsed.position;
+		if (!V.IsGoodPosition(fenParsed.position))
+			return false;
+		// 2) Check turn
+		if (!fenParsed.turn || !V.IsGoodTurn(fenParsed.turn))
+			return false;
+		// 3) Check flags
+		if (V.HasFlags && (!fenParsed.flags || !V.IsGoodFlags(fenParsed.flags)))
+			return false;
+		// 4) Check enpassant
+		if (V.HasEnpassant &&
+			(!fenParsed.enpassant || !V.IsGoodEnpassant(fenParsed.enpassant)))
+		{
+			return false;
+		}
+		return true;
+	}
+
+	// Is position part of the FEN a priori correct?
+	static IsGoodPosition(position)
+	{
+		if (position.length == 0)
+			return false;
 		const rows = position.split("/");
 		if (rows.length != V.size.x)
 			return false;
@@ -79,32 +104,50 @@ class ChessRules
 			if (sumElts != V.size.y)
 				return false;
 		}
-		// 2) Check flags (if present)
-		if (!!fenParsed.flags && !V.IsGoodFlags(fenParsed.flags))
-			return false;
-		// 3) Check turn (if present)
-		if (!!fenParsed.turn && !["w","b"].includes(fenParsed.turn))
-			return false;
-		// 4) Check enpassant (if present)
-		if (!!fenParsed.enpassant)
+		return true;
+	}
+
+	// For FEN checking
+	static IsGoodTurn(turn)
+	{
+		return ["w","b"].includes(turn);
+	}
+
+	// For FEN checking
+	static IsGoodFlags(flags)
+	{
+		return !!flags.match(/^[01]{4,4}$/);
+	}
+
+	static IsGoodEnpassant(enpassant)
+	{
+		if (enpassant != "-")
 		{
 			const ep = V.SquareToCoords(fenParsed.enpassant);
-			if (ep.y < 0 || ep.y > V.size.y || isNaN(ep.x) || ep.x < 0 || ep.x > V.size.x)
+			if (isNaN(ep.x) || !V.OnBoard(ep))
 				return false;
 		}
 		return true;
 	}
 
-	// For FEN checking
-	static IsGoodFlags(flags)
+	// 3 --> d (column number to letter)
+	static CoordToColumn(colnum)
 	{
-		return !!flags.match(/^[01]{4,4}$/);
+		return String.fromCharCode(97 + colnum);
+	}
+
+	// d --> 3 (column letter to number)
+	static ColumnToCoord(column)
+	{
+		return column.charCodeAt(0) - 97;
 	}
 
 	// a4 --> {x:3,y:0}
 	static SquareToCoords(sq)
 	{
 		return {
+			// NOTE: column is always one char => max 26 columns
+			// row is counted from black side => subtraction
 			x: V.size.x - parseInt(sq.substr(1)),
 			y: sq[0].charCodeAt() - 97
 		};
@@ -113,7 +156,7 @@ class ChessRules
 	// {x:0,y:4} --> e8
 	static CoordsToSquare(coords)
 	{
-		return String.fromCharCode(97 + coords.y) + (V.size.x - coords.x);
+		return V.CoordToColumn(coords.y) + (V.size.x - coords.x);
 	}
 
 	// Aggregates flags into one object
@@ -138,10 +181,7 @@ class ChessRules
 			const square = moveOrSquare;
 			if (square == "-")
 				return undefined;
-			return {
-				x: square[0].charCodeAt()-97,
-				y: V.size.x-parseInt(square[1])
-			};
+			return V.SquareToCoords(square);
 		}
 		// Argument is a move:
 		const move = moveOrSquare;
@@ -174,16 +214,12 @@ class ChessRules
 		return (this.turn == side && this.getColor(x,y) == side);
 	}
 
-	// On which squares is opponent under check after our move ? (for interface)
-	getCheckSquares(move)
+	// On which squares is color under check ? (for interface)
+	getCheckSquares(color)
 	{
-		this.play(move);
-		const color = this.turn; //opponent
-		let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)])
+		return this.isAttacked(this.kingPos[color], [this.getOppCol(color)])
 			? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate!
 			: [];
-		this.undo(move);
-		return res;
 	}
 
 	/////////////
@@ -200,31 +236,32 @@ class ChessRules
 
 			// Get random squares for bishops
 			let randIndex = 2 * _.random(3);
-			let bishop1Pos = positions[randIndex];
+			const bishop1Pos = positions[randIndex];
 			// The second bishop must be on a square of different color
 			let randIndex_tmp = 2 * _.random(3) + 1;
-			let bishop2Pos = positions[randIndex_tmp];
+			const 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(5);
-			let knight1Pos = positions[randIndex];
+			const knight1Pos = positions[randIndex];
 			positions.splice(randIndex, 1);
 			randIndex = _.random(4);
-			let knight2Pos = positions[randIndex];
+			const knight2Pos = positions[randIndex];
 			positions.splice(randIndex, 1);
 
 			// Get random square for queen
 			randIndex = _.random(3);
-			let queenPos = positions[randIndex];
+			const queenPos = 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];
+			// Rooks and king positions are now fixed,
+			// because of the ordering rook-king-rook
+			const rook1Pos = positions[0];
+			const kingPos = positions[1];
+			const rook2Pos = positions[2];
 
 			// Finally put the shuffled pieces in the board array
 			pieces[c][rook1Pos] = 'r';
@@ -246,19 +283,25 @@ class ChessRules
 	static ParseFen(fen)
 	{
 		const fenParts = fen.split(" ");
-		return {
+		let res =
+		{
 			position: fenParts[0],
 			turn: fenParts[1],
-			flags: fenParts[2],
-			enpassant: fenParts[3],
 		};
+		let nextIdx = 2;
+		if (V.HasFlags)
+			Object.assign(res, {flags: fenParts[nextIdx++]});
+		if (V.HasEnpassant)
+			Object.assign(res, {enpassant: fenParts[nextIdx]});
+		return res;
 	}
 
 	// Return current fen (game state)
 	getFen()
 	{
-		return this.getBaseFen() + " " + this.turn + " " +
-			this.getFlagsFen() + " " + this.getEnpassantFen();
+		return this.getBaseFen() + " " + this.getTurnFen() +
+			(V.HasFlags ? (" " + this.getFlagsFen()) : "") +
+			(V.HasEnpassant ? (" " + this.getEnpassantFen()) : "");
 	}
 
 	// Position part of the FEN string
@@ -280,7 +323,7 @@ class ChessRules
 						position += emptyCount;
 						emptyCount = 0;
 					}
-					fen += V.board2fen(this.board[i][j]);
+					position += V.board2fen(this.board[i][j]);
 				}
 			}
 			if (emptyCount > 0)
@@ -294,6 +337,11 @@ class ChessRules
 		return position;
 	}
 
+	getTurnFen()
+	{
+		return this.turn;
+	}
+
 	// Flags part of the FEN string
 	getFlagsFen()
 	{
@@ -311,7 +359,7 @@ class ChessRules
 	getEnpassantFen()
 	{
 		const L = this.epSquares.length;
-		if (L == 0)
+		if (!this.epSquares[L-1])
 			return "-"; //no en-passant
 		return V.CoordsToSquare(this.epSquares[L-1]);
 	}
@@ -357,22 +405,17 @@ class ChessRules
 		this.moves = moves;
 		const fenParsed = V.ParseFen(fen);
 		this.board = V.GetBoard(fenParsed.position);
-		this.turn = (fenParsed.turn || "w");
+		this.turn = fenParsed.turn[0]; //[0] to work with MarseilleRules
 		this.setOtherVariables(fen);
 	}
 
-	// Some additional variables from FEN (variant dependant)
-	setOtherVariables(fen)
+	// Scan board for kings and rooks positions
+	scanKingsRooks(fen)
 	{
-		// Set flags and enpassant:
-		const parsedFen = V.ParseFen(fen);
-		this.setFlags(fenParsed.flags);
-		this.epSquares = [ V.SquareToCoords(parsedFen.enpassant) ];
-		// Search for king and rooks positions:
 		this.INIT_COL_KING = {'w':-1, 'b':-1};
 		this.INIT_COL_ROOK = {'w':[-1,-1], 'b':[-1,-1]};
 		this.kingPos = {'w':[-1,-1], 'b':[-1,-1]}; //squares of white and black king
-		const fenRows = parsedFen.position.split("/");
+		const fenRows = V.ParseFen(fen).position.split("/");
 		for (let i=0; i<fenRows.length; i++)
 		{
 			let k = 0; //column index on board
@@ -410,6 +453,24 @@ class ChessRules
 		}
 	}
 
+	// Some additional variables from FEN (variant dependant)
+	setOtherVariables(fen)
+	{
+		// Set flags and enpassant:
+		const parsedFen = V.ParseFen(fen);
+		if (V.HasFlags)
+			this.setFlags(parsedFen.flags);
+		if (V.HasEnpassant)
+		{
+			const epSq = parsedFen.enpassant != "-"
+				? V.SquareToCoords(parsedFen.enpassant)
+				: undefined;
+			this.epSquares = [ epSq ];
+		}
+		// Search for king and rooks positions:
+		this.scanKingsRooks(fen);
+	}
+
 	/////////////////////
 	// GETTERS & SETTERS
 
@@ -492,7 +553,8 @@ class ChessRules
 		}
 	}
 
-	// Build a regular move from its initial and destination squares; tr: transformation
+	// Build a regular move from its initial and destination squares.
+	// tr: transformation
 	getBasicMove([sx,sy], [ex,ey], tr)
 	{
 		let mv = new Move({
@@ -529,7 +591,8 @@ class ChessRules
 		return mv;
 	}
 
-	// Generic method to find possible moves of non-pawn pieces ("sliding or jumping")
+	// Generic method to find possible moves of non-pawn pieces:
+	// "sliding or jumping"
 	getSlideNJumpMoves([x,y], steps, oneStep)
 	{
 		const color = this.getColor(x,y);
@@ -559,74 +622,66 @@ class ChessRules
 		const color = this.turn;
 		let moves = [];
 		const [sizeX,sizeY] = [V.size.x,V.size.y];
-		const shift = (color == "w" ? -1 : 1);
+		const shiftX = (color == "w" ? -1 : 1);
 		const firstRank = (color == 'w' ? sizeX-1 : 0);
 		const startRank = (color == "w" ? sizeX-2 : 1);
 		const lastRank = (color == "w" ? 0 : sizeX-1);
+		const pawnColor = this.getColor(x,y); //can be different for checkered
 
-		if (x+shift >= 0 && x+shift < sizeX && x+shift != lastRank)
+		// NOTE: next condition is generally true (no pawn on last rank)
+		if (x+shiftX >= 0 && x+shiftX < sizeX)
 		{
-			// Normal moves
-			if (this.board[x+shift][y] == V.EMPTY)
+			const finalPieces = x + shiftX == lastRank
+				? [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN]
+				: [V.PAWN]
+			// One square forward
+			if (this.board[x+shiftX][y] == V.EMPTY)
 			{
-				moves.push(this.getBasicMove([x,y], [x+shift,y]));
-				// Next condition because variants with pawns on 1st rank allow them to jump
-				if ([startRank,firstRank].includes(x) && this.board[x+2*shift][y] == V.EMPTY)
+				for (let piece of finalPieces)
+				{
+					moves.push(this.getBasicMove([x,y], [x+shiftX,y],
+						{c:pawnColor,p:piece}));
+				}
+				// Next condition because pawns on 1st rank can generally jump
+				if ([startRank,firstRank].includes(x)
+					&& this.board[x+2*shiftX][y] == V.EMPTY)
 				{
 					// Two squares jump
-					moves.push(this.getBasicMove([x,y], [x+2*shift,y]));
+					moves.push(this.getBasicMove([x,y], [x+2*shiftX,y]));
 				}
 			}
 			// Captures
-			if (y>0 && this.board[x+shift][y-1] != V.EMPTY
-				&& this.canTake([x,y], [x+shift,y-1]))
-			{
-				moves.push(this.getBasicMove([x,y], [x+shift,y-1]));
-			}
-			if (y<sizeY-1 && this.board[x+shift][y+1] != V.EMPTY
-				&& this.canTake([x,y], [x+shift,y+1]))
+			for (let shiftY of [-1,1])
 			{
-				moves.push(this.getBasicMove([x,y], [x+shift,y+1]));
-			}
-		}
-
-		if (x+shift == lastRank)
-		{
-			// Promotion
-			const pawnColor = this.getColor(x,y); //can be different for checkered
-			let promotionPieces = [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN];
-			promotionPieces.forEach(p => {
-				// Normal move
-				if (this.board[x+shift][y] == V.EMPTY)
-					moves.push(this.getBasicMove([x,y], [x+shift,y], {c:pawnColor,p:p}));
-				// Captures
-				if (y>0 && this.board[x+shift][y-1] != V.EMPTY
-					&& this.canTake([x,y], [x+shift,y-1]))
-				{
-					moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:pawnColor,p:p}));
-				}
-				if (y<sizeY-1 && this.board[x+shift][y+1] != V.EMPTY
-					&& this.canTake([x,y], [x+shift,y+1]))
+				if (y + shiftY >= 0 && y + shiftY < sizeY
+					&& this.board[x+shiftX][y+shiftY] != V.EMPTY
+					&& this.canTake([x,y], [x+shiftX,y+shiftY]))
 				{
-					moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:pawnColor,p:p}));
+					for (let piece of finalPieces)
+					{
+						moves.push(this.getBasicMove([x,y], [x+shiftX,y+shiftY],
+							{c:pawnColor,p:piece}));
+					}
 				}
-			});
+			}
 		}
 
-		// En passant
-		const Lep = this.epSquares.length;
-		const epSquare = (Lep>0 ? this.epSquares[Lep-1] : undefined);
-		if (!!epSquare && epSquare.x == x+shift && Math.abs(epSquare.y - y) == 1)
+		if (V.HasEnpassant)
 		{
-			const epStep = epSquare.y - y;
-			let enpassantMove = this.getBasicMove([x,y], [x+shift,y+epStep]);
-			enpassantMove.vanish.push({
-				x: x,
-				y: y+epStep,
-				p: 'p',
-				c: this.getColor(x,y+epStep)
-			});
-			moves.push(enpassantMove);
+			// En passant
+			const Lep = this.epSquares.length;
+			const epSquare = this.epSquares[Lep-1]; //always at least one element
+			if (!!epSquare && epSquare.x == x+shiftX && Math.abs(epSquare.y - y) == 1)
+			{
+				let enpassantMove = this.getBasicMove([x,y], [epSquare.x,epSquare.y]);
+				enpassantMove.vanish.push({
+					x: x,
+					y: epSquare.y,
+					p: 'p',
+					c: this.getColor(x,epSquare.y)
+				});
+				moves.push(enpassantMove);
+			}
 		}
 
 		return moves;
@@ -653,7 +708,8 @@ class ChessRules
 	// What are the queen moves from square x,y ?
 	getPotentialQueenMoves(sq)
 	{
-		return this.getSlideNJumpMoves(sq, V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
+		return this.getSlideNJumpMoves(sq,
+			V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
 	}
 
 	// What are the king moves from square x,y ?
@@ -683,13 +739,15 @@ class ChessRules
 				continue;
 			// If this code is reached, rooks and king are on initial position
 
-			// Nothing on the path of the king (and no checks; OK also if y==finalSquare)?
+			// Nothing on the path of the king ?
+			// (And no checks; OK also if y==finalSquare)
 			let step = finalSquares[castleSide][0] < y ? -1 : 1;
 			for (i=y; i!=finalSquares[castleSide][0]; i+=step)
 			{
 				if (this.isAttacked([x,i], [oppCol]) || (this.board[x][i] != V.EMPTY &&
 					// NOTE: next check is enough, because of chessboard constraints
-					(this.getColor(x,i) != c || ![V.KING,V.ROOK].includes(this.getPiece(x,i)))))
+					(this.getColor(x,i) != c
+						|| ![V.KING,V.ROOK].includes(this.getPiece(x,i)))))
 				{
 					continue castlingCheck;
 				}
@@ -735,9 +793,9 @@ class ChessRules
 	////////////////////
 	// MOVES VALIDATION
 
+	// For the interface: possible moves for the current turn from square sq
 	getPossibleMovesFrom(sq)
 	{
-		// Assuming color is right (already checked)
 		return this.filterValid( this.getPotentialMovesFrom(sq) );
 	}
 
@@ -746,10 +804,17 @@ class ChessRules
 	{
 		if (moves.length == 0)
 			return [];
-		return moves.filter(m => { return !this.underCheck(m); });
+		const color = this.turn;
+		return moves.filter(m => {
+			this.play(m);
+			const res = !this.underCheck(color);
+			this.undo(m);
+			return res;
+		});
 	}
 
-	// Search for all valid moves considering current turn (for engine and game end)
+	// Search for all valid moves considering current turn
+	// (for engine and game end)
 	getAllValidMoves()
 	{
 		const color = this.turn;
@@ -759,13 +824,14 @@ class ChessRules
 		{
 			for (let j=0; j<V.size.y; j++)
 			{
-				// Next condition "!= oppCol" = harmless hack to work with checkered variant
+				// Next condition "!= oppCol" to work with checkered variant
 				if (this.board[i][j] != V.EMPTY && this.getColor(i,j) != oppCol)
-					Array.prototype.push.apply(potentialMoves, this.getPotentialMovesFrom([i,j]));
+				{
+					Array.prototype.push.apply(potentialMoves,
+						this.getPotentialMovesFrom([i,j]));
+				}
 			}
 		}
-		// NOTE: prefer lazy undercheck tests, letting the king being taken?
-		// No: if happen on last 1/2 move, could lead to forbidden moves, wrong evals
 		return this.filterValid(potentialMoves);
 	}
 
@@ -795,7 +861,7 @@ class ChessRules
 		return false;
 	}
 
-	// Check if pieces of color in array 'colors' are attacking (king) on square x,y
+	// Check if pieces of color in 'colors' are attacking (king) on square x,y
 	isAttacked(sq, colors)
 	{
 		return (this.isAttackedByPawn(sq, colors)
@@ -881,14 +947,10 @@ class ChessRules
 		return false;
 	}
 
-	// Is current player under check after his move ?
-	underCheck(move)
+	// Is color under check after his move ?
+	underCheck(color)
 	{
-		const color = this.turn;
-		this.play(move);
-		let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)]);
-		this.undo(move);
-		return res;
+		return this.isAttacked(this.kingPos[color], [this.getOppCol(color)]);
 	}
 
 	/////////////////
@@ -911,11 +973,28 @@ class ChessRules
 			board[psq.x][psq.y] = psq.c + psq.p;
 	}
 
-	// Before move is played, update variables + flags
+	// After move is played, update variables + flags
 	updateVariables(move)
 	{
-		const piece = this.getPiece(move.start.x,move.start.y);
-		const c = this.turn;
+		let piece = undefined;
+		let c = undefined;
+		if (move.vanish.length >= 1)
+		{
+			// Usual case, something is moved
+			piece = move.vanish[0].p;
+			c = move.vanish[0].c;
+		}
+		else
+		{
+			// Crazyhouse-like variants
+			piece = move.appear[0].p;
+			c = move.appear[0].c;
+		}
+		if (c == "c") //if (!["w","b"].includes(c))
+		{
+			// 'c = move.vanish[0].c' doesn't work for Checkered
+			c = this.getOppCol(this.turn);
+		}
 		const firstRank = (c == "w" ? V.size.x-1 : 0);
 
 		// Update king position + flags
@@ -923,22 +1002,27 @@ class ChessRules
 		{
 			this.kingPos[c][0] = move.appear[0].x;
 			this.kingPos[c][1] = move.appear[0].y;
-			this.castleFlags[c] = [false,false];
+			if (V.HasFlags)
+				this.castleFlags[c] = [false,false];
 			return;
 		}
-		const oppCol = this.getOppCol(c);
-		const oppFirstRank = (V.size.x-1) - firstRank;
-		if (move.start.x == firstRank //our rook moves?
-			&& this.INIT_COL_ROOK[c].includes(move.start.y))
-		{
-			const flagIdx = (move.start.y == this.INIT_COL_ROOK[c][0] ? 0 : 1);
-			this.castleFlags[c][flagIdx] = false;
-		}
-		else if (move.end.x == oppFirstRank //we took opponent rook?
-			&& this.INIT_COL_ROOK[oppCol].includes(move.end.y))
+		if (V.HasFlags)
 		{
-			const flagIdx = (move.end.y == this.INIT_COL_ROOK[oppCol][0] ? 0 : 1);
-			this.castleFlags[oppCol][flagIdx] = false;
+			// Update castling flags if rooks are moved
+			const oppCol = this.getOppCol(c);
+			const oppFirstRank = (V.size.x-1) - firstRank;
+			if (move.start.x == firstRank //our rook moves?
+				&& this.INIT_COL_ROOK[c].includes(move.start.y))
+			{
+				const flagIdx = (move.start.y == this.INIT_COL_ROOK[c][0] ? 0 : 1);
+				this.castleFlags[c][flagIdx] = false;
+			}
+			else if (move.end.x == oppFirstRank //we took opponent rook?
+				&& this.INIT_COL_ROOK[oppCol].includes(move.end.y))
+			{
+				const flagIdx = (move.end.y == this.INIT_COL_ROOK[oppCol][0] ? 0 : 1);
+				this.castleFlags[oppCol][flagIdx] = false;
+			}
 		}
 	}
 
@@ -961,28 +1045,32 @@ class ChessRules
 		if (!!ingame)
 			move.notation = [this.getNotation(move), this.getLongNotation(move)];
 
-		move.flags = JSON.stringify(this.aggregateFlags()); //save flags (for undo)
-		this.updateVariables(move);
-		this.moves.push(move);
-		this.epSquares.push( this.getEpSquare(move) );
-		this.turn = this.getOppCol(this.turn);
+		if (V.HasFlags)
+			move.flags = JSON.stringify(this.aggregateFlags()); //save flags (for undo)
+		if (V.HasEnpassant)
+			this.epSquares.push( this.getEpSquare(move) );
 		V.PlayOnBoard(this.board, move);
+		this.turn = this.getOppCol(this.turn);
+		this.moves.push(move);
+		this.updateVariables(move);
 
 		if (!!ingame)
 		{
 			// Hash of current game state *after move*, to detect repetitions
-			move.hash = hex_md5(this.getFen();
+			move.hash = hex_md5(this.getFen());
 		}
 	}
 
 	undo(move)
 	{
+		if (V.HasEnpassant)
+			this.epSquares.pop();
+		if (V.HasFlags)
+			this.disaggregateFlags(JSON.parse(move.flags));
 		V.UndoOnBoard(this.board, move);
 		this.turn = this.getOppCol(this.turn);
-		this.epSquares.pop();
 		this.moves.pop();
 		this.unupdateVariables(move);
-		this.disaggregateFlags(JSON.parse(move.flags));
 
 		// DEBUG:
 //		if (this.getFen() != this.states[this.states.length-1])
@@ -1034,7 +1122,7 @@ class ChessRules
 		if (!this.isAttacked(this.kingPos[color], [this.getOppCol(color)]))
 			return "1/2";
 		// OK, checkmate
-		return color == "w" ? "0-1" : "1-0";
+		return (color == "w" ? "0-1" : "1-0");
 	}
 
 	///////////////
@@ -1092,12 +1180,14 @@ class ChessRules
 		// Rank moves using a min-max at depth 2
 		for (let i=0; i<moves1.length; i++)
 		{
-			moves1[i].eval = (color=="w" ? -1 : 1) * maxeval; //very low, I'm checkmated
+			// Initial self evaluation is very low: "I'm checkmated"
+			moves1[i].eval = (color=="w" ? -1 : 1) * maxeval;
 			this.play(moves1[i]);
 			let eval2 = undefined;
 			if (this.atLeastOneMove())
 			{
-				eval2 = (color=="w" ? 1 : -1) * maxeval; //initialized with checkmate value
+				// Initial enemy evaluation is very low too, for him
+				eval2 = (color=="w" ? 1 : -1) * maxeval;
 				// Second half-move:
 				let moves2 = this.getAllValidMoves("computer");
 				for (let j=0; j<moves2.length; j++)
@@ -1112,8 +1202,11 @@ class ChessRules
 						const score = this.checkGameEnd();
 						evalPos = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
 					}
-					if ((color == "w" && evalPos < eval2) || (color=="b" && evalPos > eval2))
+					if ((color == "w" && evalPos < eval2)
+						|| (color=="b" && evalPos > eval2))
+					{
 						eval2 = evalPos;
+					}
 					this.undo(moves2[j]);
 				}
 			}
@@ -1152,11 +1245,12 @@ class ChessRules
 					this.alphabeta(V.SEARCH_DEPTH-1, -maxeval, maxeval);
 				this.undo(moves1[i]);
 			}
-			moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
+			moves1.sort( (a,b) => {
+				return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
 		}
 		else
 			return currentBest;
-		//console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
+//		console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
 
 		candidates = [0];
 		for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++)
@@ -1249,12 +1343,12 @@ class ChessRules
 			if (move.vanish.length > move.appear.length)
 			{
 				// Capture
-				const startColumn = String.fromCharCode(97 + move.start.y);
+				const startColumn = V.CoordToColumn(move.start.y);
 				notation = startColumn + "x" + finalSquare;
 			}
 			else //no capture
 				notation = finalSquare;
-			if (move.appear.length > 0 && piece != move.appear[0].p) //promotion
+			if (move.appear.length > 0 && move.appear[0].p != V.PAWN) //promotion
 				notation += "=" + move.appear[0].p.toUpperCase();
 			return notation;
 		}