X-Git-Url: https://git.auder.net/?a=blobdiff_plain;f=public%2Fjavascripts%2Fbase_rules.js;h=750cd2d4ab72313fc4e1149dd76103ff4926147a;hb=32cfcea44bf00b0c6c4d172cca715823076ff490;hp=6bc3591cfc601c3604a4f7c7f7f0619db8c5b553;hpb=8a60cacd26d8c47f52ecac26091d6a6f65e6bbc5;p=vchess.git

diff --git a/public/javascripts/base_rules.js b/public/javascripts/base_rules.js
index 6bc3591c..750cd2d4 100644
--- a/public/javascripts/base_rules.js
+++ b/public/javascripts/base_rules.js
@@ -1,3 +1,6 @@
+// (Orthodox) Chess rules are defined in ChessRules class.
+// Variants generally inherit from it, and modify some parts.
+
 class PiPo //Piece+Position
 {
 	// o: {piece[p], color[c], posX[x], posY[y]}
@@ -10,6 +13,7 @@ class PiPo //Piece+Position
 	}
 }
 
+// TODO: for animation, moves should contains "moving" and "fading" maybe...
 class Move
 {
 	// o: {appear, vanish, [start,] [end,]}
@@ -60,7 +64,7 @@ class ChessRules
 	{
 		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]}; //respective squares of white and black king
+		this.kingPos = {'w':[-1,-1], 'b':[-1,-1]}; //squares of white and black king
 		const fenParts = fen.split(" ");
 		const position = fenParts[0].split("/");
 		for (let i=0; i<position.length; i++)
@@ -124,7 +128,7 @@ class ChessRules
 		return board;
 	}
 
-	// Overridable: flags can change a lot
+	// Extract (relevant) flags from fen
 	setFlags(fen)
 	{
 		// white a-castle, h-castle, black a-castle, h-castle
@@ -137,7 +141,6 @@ class ChessRules
 	///////////////////
 	// GETTERS, SETTERS
 
-	// Simple useful getters
 	static get size() { return [8,8]; }
 	// Two next functions return 'undefined' if called on empty square
 	getColor(i,j) { return this.board[i][j].charAt(0); }
@@ -199,7 +202,7 @@ class ChessRules
 		return undefined; //default
 	}
 
-	// can thing on square1 take thing on square2
+	// Can thing on square1 take thing on square2
 	canTake([x1,y1], [x2,y2])
 	{
 		return this.getColor(x1,y1) != this.getColor(x2,y2);
@@ -291,7 +294,7 @@ class ChessRules
 		return moves;
 	}
 
-	// What are the pawn moves from square x,y considering color "color" ?
+	// What are the pawn moves from square x,y ?
 	getPotentialPawnMoves([x,y])
 	{
 		const color = this.turn;
@@ -332,21 +335,22 @@ class ChessRules
 		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:color,p:p}));
+					moves.push(this.getBasicMove([x,y], [x+shift,y], {c:pawnColor,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}));
+					moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:pawnColor,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}));
+					moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:pawnColor,p:p}));
 				}
 			});
 		}
@@ -379,7 +383,8 @@ class ChessRules
 	// What are the knight moves from square x,y ?
 	getPotentialKnightMoves(sq)
 	{
-		return this.getSlideNJumpMoves(sq, VariantRules.steps[VariantRules.KNIGHT], "oneStep");
+		return this.getSlideNJumpMoves(
+			sq, VariantRules.steps[VariantRules.KNIGHT], "oneStep");
 	}
 
 	// What are the bishop moves from square x,y ?
@@ -480,7 +485,8 @@ class ChessRules
 
 	canIplay(side, [x,y])
 	{
-		return ((side=='w' && this.moves.length%2==0) || (side=='b' && this.moves.length%2==1))
+		return ((side=='w' && this.moves.length%2==0)
+				|| (side=='b' && this.moves.length%2==1))
 			&& this.getColor(x,y) == side;
 	}
 
@@ -490,7 +496,7 @@ class ChessRules
 		return this.filterValid( this.getPotentialMovesFrom(sq) );
 	}
 
-	// TODO: once a promotion is filtered, the others results are same: useless computations
+	// TODO: promotions (into R,B,N,Q) should be filtered only once
 	filterValid(moves)
 	{
 		if (moves.length == 0)
@@ -509,7 +515,7 @@ class ChessRules
 		{
 			for (let j=0; j<sizeY; j++)
 			{
-				// Next condition ... != oppCol is a little HACK to work with checkered variant
+				// Next condition "!= oppCol" = harmless hack to work with checkered variant
 				if (this.board[i][j] != VariantRules.EMPTY && this.getColor(i,j) != oppCol)
 					Array.prototype.push.apply(potentialMoves, this.getPotentialMovesFrom([i,j]));
 			}
@@ -546,7 +552,7 @@ class ChessRules
 		return false;
 	}
 
-	// Check if pieces of color 'colors' are attacking square x,y
+	// Check if pieces of color in array 'colors' are attacking square x,y
 	isAttacked(sq, colors)
 	{
 		return (this.isAttackedByPawn(sq, colors)
@@ -557,7 +563,7 @@ class ChessRules
 			|| this.isAttackedByKing(sq, colors));
 	}
 
-	// Is square x,y attacked by pawns of color c ?
+	// Is square x,y attacked by 'colors' pawns ?
 	isAttackedByPawn([x,y], colors)
 	{
 		const [sizeX,sizeY] = VariantRules.size;
@@ -579,28 +585,28 @@ class ChessRules
 		return false;
 	}
 
-	// Is square x,y attacked by rooks of color c ?
+	// Is square x,y attacked by 'colors' rooks ?
 	isAttackedByRook(sq, colors)
 	{
 		return this.isAttackedBySlideNJump(sq, colors,
 			VariantRules.ROOK, VariantRules.steps[VariantRules.ROOK]);
 	}
 
-	// Is square x,y attacked by knights of color c ?
+	// Is square x,y attacked by 'colors' knights ?
 	isAttackedByKnight(sq, colors)
 	{
 		return this.isAttackedBySlideNJump(sq, colors,
 			VariantRules.KNIGHT, VariantRules.steps[VariantRules.KNIGHT], "oneStep");
 	}
 
-	// Is square x,y attacked by bishops of color c ?
+	// Is square x,y attacked by 'colors' bishops ?
 	isAttackedByBishop(sq, colors)
 	{
 		return this.isAttackedBySlideNJump(sq, colors,
 			VariantRules.BISHOP, VariantRules.steps[VariantRules.BISHOP]);
 	}
 
-	// Is square x,y attacked by queens of color c ?
+	// Is square x,y attacked by 'colors' queens ?
 	isAttackedByQueen(sq, colors)
 	{
 		const V = VariantRules;
@@ -608,7 +614,7 @@ class ChessRules
 			V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
 	}
 
-	// Is square x,y attacked by king of color c ?
+	// Is square x,y attacked by 'colors' king(s) ?
 	isAttackedByKing(sq, colors)
 	{
 		const V = VariantRules;
@@ -617,7 +623,7 @@ class ChessRules
 	}
 
 	// Generic method for non-pawn pieces ("sliding or jumping"):
-	// is x,y attacked by piece !of color in colors?
+	// is x,y attacked by a piece of color in array 'colors' ?
 	isAttackedBySlideNJump([x,y], colors, piece, steps, oneStep)
 	{
 		const [sizeX,sizeY] = VariantRules.size;
@@ -640,7 +646,7 @@ class ChessRules
 		return false;
 	}
 
-	// Is color c under check after move ?
+	// Is current player under check after his move ?
 	underCheck(move)
 	{
 		const color = this.turn;
@@ -650,7 +656,7 @@ class ChessRules
 		return res;
 	}
 
-	// On which squares is color c under check (after move) ?
+	// On which squares is opponent under check after our move ?
 	getCheckSquares(move)
 	{
 		this.play(move);
@@ -711,6 +717,8 @@ class ChessRules
 		}
 	}
 
+	// After move is undo-ed, un-update variables (flags are reset)
+	// TODO: more symmetry, by storing flags increment in move...
 	unupdateVariables(move)
 	{
 		// (Potentially) Reset king position
@@ -721,12 +729,6 @@ class ChessRules
 
 	play(move, ingame)
 	{
-		// DEBUG:
-//		if (!this.states) this.states = [];
-//		if (!ingame) this.states.push(JSON.stringify(this.board));
-//		if (!this.rstates) this.rstates = [];
-//		if (!ingame) this.rstates.push(JSON.stringify(this.promoted)+"-"+JSON.stringify(this.reserve));
-
 		if (!!ingame)
 			move.notation = [this.getNotation(move), this.getLongNotation(move)];
 
@@ -744,23 +746,17 @@ class ChessRules
 		this.moves.pop();
 		this.unupdateVariables(move);
 		this.parseFlags(JSON.parse(move.flags));
-
-		// DEBUG:
-//		let state = this.states.pop();
-//		let rstate = this.rstates.pop();
-//		if (JSON.stringify(this.board) != state || JSON.stringify(this.promoted)+"-"+JSON.stringify(this.reserve) != rstate)
-//			debugger;
 	}
 
 	//////////////
 	// END OF GAME
 
+	// Basic check for 3 repetitions (in the last moves only)
+	// TODO: extend to usual 3-repetition recognition (storing FEN with move?)
 	checkRepetition()
 	{
-		// Check for 3 repetitions
 		if (this.moves.length >= 8)
 		{
-			// NOTE: crude detection, only moves repetition
 			const L = this.moves.length;
 			if (_.isEqual(this.moves[L-1], this.moves[L-5]) &&
 				_.isEqual(this.moves[L-2], this.moves[L-6]) &&
@@ -773,6 +769,7 @@ class ChessRules
 		return false;
 	}
 
+	// Is game over ? And if yes, what is the score ?
 	checkGameOver()
 	{
 		if (this.checkRepetition())
@@ -828,10 +825,11 @@ class ChessRules
 	// NOTE: works also for extinction chess because depth is 3...
 	getComputerMove()
 	{
-		this.shouldReturn = false;
 		const maxeval = VariantRules.INFINITY;
 		const color = this.turn;
-		let moves1 = this.getAllValidMoves();
+		// Some variants may show a bigger moves list to the human (Switching),
+		// thus the argument "computer" below (which is generally ignored)
+		let moves1 = this.getAllValidMoves("computer");
 
 		// Can I mate in 1 ? (for Magnetic & Extinction)
 		for (let i of _.shuffle(_.range(moves1.length)))
@@ -847,41 +845,61 @@ class ChessRules
 		for (let i=0; i<moves1.length; i++)
 		{
 			moves1[i].eval = (color=="w" ? -1 : 1) * maxeval; //very low, I'm checkmated
-			let eval2 = (color=="w" ? 1 : -1) * maxeval; //initialized with checkmate value
 			this.play(moves1[i]);
-			// Second half-move:
-			let moves2 = this.getAllValidMoves();
-			// If no possible moves AND underCheck, eval2 is correct.
-			// If !underCheck, eval2 is 0 (stalemate).
-			if (moves2.length == 0 && this.checkGameEnd() == "1/2")
-				eval2 = 0;
-			for (let j=0; j<moves2.length; j++)
+			let eval2 = undefined;
+			if (this.atLeastOneMove())
+			{
+				eval2 = (color=="w" ? 1 : -1) * maxeval; //initialized with checkmate value
+				// Second half-move:
+				let moves2 = this.getAllValidMoves("computer");
+				for (let j=0; j<moves2.length; j++)
+				{
+					this.play(moves2[j]);
+					let evalPos = undefined;
+					if (this.atLeastOneMove())
+						evalPos = this.evalPosition()
+					else
+					{
+						// Work with scores for Loser variant
+						const score = this.checkGameEnd();
+						evalPos = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
+					}
+					if ((color == "w" && evalPos < eval2) || (color=="b" && evalPos > eval2))
+						eval2 = evalPos;
+					this.undo(moves2[j]);
+				}
+			}
+			else
 			{
-				this.play(moves2[j]);
-				let evalPos = this.evalPosition();
-				if ((color == "w" && evalPos < eval2) || (color=="b" && evalPos > eval2))
-					eval2 = evalPos;
-				this.undo(moves2[j]);
+				const score = this.checkGameEnd();
+				eval2 = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
 			}
-			if ((color=="w" && eval2 > moves1[i].eval) || (color=="b" && eval2 < moves1[i].eval))
+			if ((color=="w" && eval2 > moves1[i].eval)
+				|| (color=="b" && eval2 < moves1[i].eval))
+			{
 				moves1[i].eval = eval2;
+			}
 			this.undo(moves1[i]);
 		}
 		moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
+		//console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
 
 		let candidates = [0]; //indices of candidates moves
 		for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++)
 			candidates.push(j);
 		let currentBest = moves1[_.sample(candidates, 1)];
 
+		// From here, depth >= 3: may take a while, so we control time
+		const timeStart = Date.now();
+
 		// Skip depth 3+ if we found a checkmate (or if we are checkmated in 1...)
 		if (VariantRules.SEARCH_DEPTH >= 3
 			&& Math.abs(moves1[0].eval) < VariantRules.THRESHOLD_MATE)
 		{
 			for (let i=0; i<moves1.length; i++)
 			{
-				if (this.shouldReturn)
-					return currentBest; //depth-2, minimum
+				if (Date.now()-timeStart >= 5000) //more than 5 seconds
+					return currentBest; //depth 2 at least
 				this.play(moves1[i]);
 				// 0.1 * oldEval : heuristic to avoid some bad moves (not all...)
 				moves1[i].eval = 0.1*moves1[i].eval +
@@ -892,11 +910,11 @@ class ChessRules
 		}
 		else
 			return currentBest;
+		//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++)
 			candidates.push(j);
-//		console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
 		return moves1[_.sample(candidates, 1)];
 	}
 
@@ -908,13 +926,16 @@ class ChessRules
 		{
 			switch (this.checkGameEnd())
 			{
-				case "1/2": return 0;
-				default: return color=="w" ? -maxeval : maxeval;
+				case "1/2":
+					return 0;
+				default:
+					const score = this.checkGameEnd();
+					return (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
 			}
 		}
 		if (depth == 0)
       return this.evalPosition();
-		const moves = this.getAllValidMoves();
+		const moves = this.getAllValidMoves("computer");
     let v = color=="w" ? -maxeval : maxeval;
 		if (color == "w")
 		{
@@ -965,12 +986,12 @@ class ChessRules
 	////////////
 	// FEN utils
 
-	// Overridable..
+	// Setup the initial random (assymetric) position
 	static GenRandInitFen()
 	{
-		let pieces = [new Array(8), new Array(8)];
+		let pieces = { "w": new Array(8), "b": new Array(8) };
 		// Shuffle pieces on first and last rank
-		for (let c = 0; c <= 1; c++)
+		for (let c of ["w","b"])
 		{
 			let positions = _.range(8);
 
@@ -1012,9 +1033,9 @@ class ChessRules
 			pieces[c][knight2Pos] = 'n';
 			pieces[c][rook2Pos] = 'r';
 		}
-		let fen = pieces[0].join("") +
+		let fen = pieces["b"].join("") +
 			"/pppppppp/8/8/8/8/PPPPPPPP/" +
-			pieces[1].join("").toUpperCase() +
+			pieces["w"].join("").toUpperCase() +
 			" 1111"; //add flags
 		return fen;
 	}
@@ -1025,6 +1046,7 @@ class ChessRules
 		return this.getBaseFen() + " " + this.getFlagsFen();
 	}
 
+	// Position part of the FEN string
 	getBaseFen()
 	{
 		let fen = "";
@@ -1058,7 +1080,7 @@ class ChessRules
 		return fen;
 	}
 
-	// Overridable..
+	// Flags part of the FEN string
 	getFlagsFen()
 	{
 		let fen = "";
@@ -1066,7 +1088,7 @@ class ChessRules
 		for (let i of ['w','b'])
 		{
 			for (let j=0; j<2; j++)
-				fen += this.castleFlags[i][j] ? '1' : '0';
+				fen += (this.castleFlags[i][j] ? '1' : '0');
 		}
 		return fen;
 	}
@@ -1074,14 +1096,8 @@ class ChessRules
 	// Context: just before move is played, turn hasn't changed
 	getNotation(move)
 	{
-		if (move.appear.length == 2 && move.appear[0].p == VariantRules.KING)
-		{
-			// Castle
-			if (move.end.y < move.start.y)
-				return "0-0-0";
-			else
-				return "0-0";
-		}
+		if (move.appear.length == 2 && move.appear[0].p == VariantRules.KING) //castle
+			return (move.end.y < move.start.y ? "0-0-0" : "0-0");
 
 		// Translate final square
 		const finalSquare =
@@ -1126,15 +1142,18 @@ class ChessRules
 	// The score is already computed when calling this function
 	getPGN(mycolor, score, fenStart, mode)
 	{
+		const zeroPad = x => { return (x<10 ? "0" : "") + x; };
 		let pgn = "";
 		pgn += '[Site "vchess.club"]<br>';
 		const d = new Date();
 		const opponent = mode=="human" ? "Anonymous" : "Computer";
 		pgn += '[Variant "' + variant + '"]<br>';
-		pgn += '[Date "' + d.getFullYear() + '-' + (d.getMonth()+1) + '-' + d.getDate() + '"]<br>';
+		pgn += '[Date "' + d.getFullYear() + '-' + (d.getMonth()+1) +
+			'-' + zeroPad(d.getDate()) + '"]<br>';
 		pgn += '[White "' + (mycolor=='w'?'Myself':opponent) + '"]<br>';
 		pgn += '[Black "' + (mycolor=='b'?'Myself':opponent) + '"]<br>';
-		pgn += '[Fen "' + fenStart + '"]<br>';
+		pgn += '[FenStart "' + fenStart + '"]<br>';
+		pgn += '[Fen "' + this.getFen() + '"]<br>';
 		pgn += '[Result "' + score + '"]<br><br>';
 
 		// Standard PGN
@@ -1144,7 +1163,7 @@ class ChessRules
 				pgn += ((i/2)+1) + ".";
 			pgn += this.moves[i].notation[0] + " ";
 		}
-		pgn += score + "<br><br>";
+		pgn += "<br><br>";
 
 		// "Complete moves" PGN (helping in ambiguous cases)
 		for (let i=0; i<this.moves.length; i++)
@@ -1153,7 +1172,6 @@ class ChessRules
 				pgn += ((i/2)+1) + ".";
 			pgn += this.moves[i].notation[1] + " ";
 		}
-		pgn += score;
 
 		return pgn;
 	}