X-Git-Url: https://git.auder.net/?p=vchess.git;a=blobdiff_plain;f=client%2Fsrc%2Fbase_rules.js;h=448604a46e27233ad8d2e3d73be438f8a5458f01;hp=a47b853f439f283a1ee57e419c87afbe17eb4c0f;hb=d54f6261c9e30f4eabb402ad301dd5c5e40fb656;hpb=933fd1f90a080c1a3e477cc36adebb5e8db8a9d3 diff --git a/client/src/base_rules.js b/client/src/base_rules.js index a47b853f..448604a4 100644 --- a/client/src/base_rules.js +++ b/client/src/base_rules.js @@ -37,7 +37,24 @@ export const ChessRules = class ChessRules { return true; } - // Some variants don't have en-passant + // Or castle + static get HasCastle() { + return V.HasFlags; + } + + // Pawns specifications + static get PawnSpecs() { + return { + directions: { 'w': -1, 'b': 1 }, + twoSquares: true, + promotions: [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN], + canCapture: true, + captureBackward: false, + bidirectional: false + }; + } + + // En-passant captures need a stack of squares: static get HasEnpassant() { return true; } @@ -60,6 +77,28 @@ export const ChessRules = class ChessRules { return V.ShowMoves; } + // Some variants always show the same orientation + static get CanFlip() { + return true; + } + get canFlip() { + return V.CanFlip; + } + + // Some variants require turn indicator + // (generally when analysis or flip is diabled) + static get ShowTurn() { + return !V.CanAnalyze || V.ShowMoves != "all" || !V.CanFlip; + } + get showTurn() { + return V.ShowTurn; + } + + static get IMAGE_EXTENSION() { + // All pieces should be in the SVG format + return ".svg"; + } + // Turn "wb" into "B" (for FEN) static board2fen(b) { return b[0] == "w" ? b[1].toUpperCase() : b[1]; @@ -70,7 +109,7 @@ export const ChessRules = class ChessRules { return f.charCodeAt() <= 90 ? "w" + f.toLowerCase() : "b" + f; } - // Check if FEN describe a board situation correctly + // Check if FEN describes a board situation correctly static IsGoodFen(fen) { const fenParsed = V.ParseFen(fen); // 1) Check position @@ -98,12 +137,11 @@ export const ChessRules = class ChessRules { if (position.length == 0) return false; const rows = position.split("/"); if (rows.length != V.size.x) return false; - let kings = {}; + let kings = { "k": 0, "K": 0 }; for (let row of rows) { let sumElts = 0; for (let i = 0; i < row.length; i++) { - if (['K','k'].includes(row[i])) - kings[row[i]] = true; + if (['K','k'].includes(row[i])) kings[row[i]]++; if (V.PIECES.includes(row[i].toLowerCase())) sumElts++; else { const num = parseInt(row[i]); @@ -113,9 +151,8 @@ export const ChessRules = class ChessRules { } if (sumElts != V.size.y) return false; } - // Both kings should be on board: - if (Object.keys(kings).length != 2) - return false; + // Both kings should be on board. Exactly one per color. + if (Object.values(kings).some(v => v != 1)) return false; return true; } @@ -126,7 +163,8 @@ export const ChessRules = class ChessRules { // For FEN checking static IsGoodFlags(flags) { - return !!flags.match(/^[01]{4,4}$/); + // NOTE: a little too permissive to work with more variants + return !!flags.match(/^[a-z]{4,4}$/); } static IsGoodEnpassant(enpassant) { @@ -162,9 +200,14 @@ export const ChessRules = class ChessRules { return V.CoordToColumn(coords.y) + (V.size.x - coords.x); } - // Path to pieces + // Path to pieces (standard ones in pieces/ folder) getPpath(b) { - return b; //usual pieces in pieces/ folder + return b; + } + + // Path to promotion pieces (usually the same) + getPPpath(b) { + return this.getPpath(b); } // Aggregates flags into one object @@ -187,17 +230,16 @@ export const ChessRules = class ChessRules { } // Argument is a move: const move = moveOrSquare; - const [sx, sy, ex] = [move.start.x, move.start.y, move.end.x]; - // NOTE: next conditions are first for Atomic, and last for Checkered + const s = move.start, + e = move.end; if ( - move.appear.length > 0 && - Math.abs(sx - ex) == 2 && - move.appear[0].p == V.PAWN && - ["w", "b"].includes(move.appear[0].c) + Math.abs(s.x - e.x) == 2 && + s.y == e.y && + move.appear[0].p == V.PAWN ) { return { - x: (sx + ex) / 2, - y: sy + x: (s.x + e.x) / 2, + y: s.y }; } return undefined; //default @@ -220,19 +262,32 @@ export const ChessRules = class ChessRules { // On which squares is color under check ? (for interface) getCheckSquares(color) { - return this.isAttacked(this.kingPos[color], [V.GetOppCol(color)]) - ? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate! - : []; + return ( + this.underCheck(color) + ? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate! + : [] + ); } ///////////// // FEN UTILS - // Setup the initial random (assymetric) position - static GenRandInitFen() { + // Setup the initial random (asymmetric) position + static GenRandInitFen(randomness) { + if (randomness == 0) + // Deterministic: + return "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w 0 ahah -"; + let pieces = { w: new Array(8), b: new Array(8) }; - // Shuffle pieces on first and last rank + let flags = ""; + // Shuffle pieces on first (and last rank if randomness == 2) for (let c of ["w", "b"]) { + if (c == 'b' && randomness == 1) { + pieces['b'] = pieces['w']; + flags += flags; + break; + } + let positions = ArrayFun.range(8); // Get random squares for bishops @@ -273,13 +328,15 @@ export const ChessRules = class ChessRules { pieces[c][bishop2Pos] = "b"; pieces[c][knight2Pos] = "n"; pieces[c][rook2Pos] = "r"; + flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos); } + // Add turn + flags + enpassant return ( pieces["b"].join("") + "/pppppppp/8/8/8/8/PPPPPPPP/" + pieces["w"].join("").toUpperCase() + - " w 0 1111 -" - ); //add turn + flags + enpassant + " w 0 " + flags + " -" + ); } // "Parse" FEN: just return untransformed string data @@ -299,18 +356,33 @@ export const ChessRules = class ChessRules { // Return current fen (game state) getFen() { return ( - this.getBaseFen() + - " " + - this.getTurnFen() + - " " + + this.getBaseFen() + " " + + this.getTurnFen() + " " + this.movesCount + (V.HasFlags ? " " + this.getFlagsFen() : "") + (V.HasEnpassant ? " " + this.getEnpassantFen() : "") ); } + getFenForRepeat() { + // Omit movesCount, only variable allowed to differ + return ( + this.getBaseFen() + "_" + + this.getTurnFen() + + (V.HasFlags ? "_" + this.getFlagsFen() : "") + + (V.HasEnpassant ? "_" + this.getEnpassantFen() : "") + ); + } + // Position part of the FEN string getBaseFen() { + const format = (count) => { + // if more than 9 consecutive free spaces, break the integer, + // otherwise FEN parsing will fail. + if (count <= 9) return count; + // Currently only boards of size up to 11 or 12: + return "9" + (count - 9); + }; let position = ""; for (let i = 0; i < V.size.x; i++) { let emptyCount = 0; @@ -319,7 +391,7 @@ export const ChessRules = class ChessRules { else { if (emptyCount > 0) { // Add empty squares in-between - position += emptyCount; + position += format(emptyCount); emptyCount = 0; } position += V.board2fen(this.board[i][j]); @@ -327,7 +399,7 @@ export const ChessRules = class ChessRules { } if (emptyCount > 0) { // "Flush remainder" - position += emptyCount; + position += format(emptyCount); } if (i < V.size.x - 1) position += "/"; //separate rows } @@ -341,10 +413,9 @@ export const ChessRules = class ChessRules { // Flags part of the FEN string getFlagsFen() { let flags = ""; - // Add castling flags - for (let i of ["w", "b"]) { - for (let j = 0; j < 2; j++) flags += this.castleFlags[i][j] ? "1" : "0"; - } + // Castling flags + for (let c of ["w", "b"]) + flags += this.castleFlags[c].map(V.CoordToColumn).join(""); return flags; } @@ -376,23 +447,22 @@ export const ChessRules = class ChessRules { // Extract (relevant) flags from fen setFlags(fenflags) { // white a-castle, h-castle, black a-castle, h-castle - this.castleFlags = { w: [true, true], b: [true, true] }; - if (!fenflags) return; - for (let i = 0; i < 4; i++) - this.castleFlags[i < 2 ? "w" : "b"][i % 2] = fenflags.charAt(i) == "1"; + this.castleFlags = { w: [-1, -1], b: [-1, -1] }; + for (let i = 0; i < 4; i++) { + this.castleFlags[i < 2 ? "w" : "b"][i % 2] = + V.ColumnToCoord(fenflags.charAt(i)); + } } ////////////////// // INITIALIZATION - constructor(fen) { - // In printDiagram() fen isn't supply because only getPpath() is used - if (fen) - this.re_init(fen); - } - // Fen string fully describes the game state - re_init(fen) { + constructor(fen) { + if (!fen) + // In printDiagram() fen isn't supply because only getPpath() is used + // TODO: find a better solution! + return; const fenParsed = V.ParseFen(fen); this.board = V.GetBoard(fenParsed.position); this.turn = fenParsed.turn[0]; //[0] to work with MarseilleRules @@ -400,12 +470,12 @@ export const ChessRules = class ChessRules { this.setOtherVariables(fen); } - // Scan board for kings and rooks positions - scanKingsRooks(fen) { + // Scan board for kings positions + scanKings(fen) { 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 = V.ParseFen(fen).position.split("/"); + const startRow = { 'w': V.size.x - 1, 'b': 0 }; for (let i = 0; i < fenRows.length; i++) { let k = 0; //column index on board for (let j = 0; j < fenRows[i].length; j++) { @@ -418,14 +488,6 @@ export const ChessRules = class ChessRules { this.kingPos["w"] = [i, k]; this.INIT_COL_KING["w"] = k; break; - case "r": - if (this.INIT_COL_ROOK["b"][0] < 0) this.INIT_COL_ROOK["b"][0] = k; - else this.INIT_COL_ROOK["b"][1] = k; - break; - case "R": - if (this.INIT_COL_ROOK["w"][0] < 0) this.INIT_COL_ROOK["w"][0] = k; - else this.INIT_COL_ROOK["w"][1] = k; - break; default: { const num = parseInt(fenRows[i].charAt(j)); if (!isNaN(num)) k += num - 1; @@ -448,8 +510,8 @@ export const ChessRules = class ChessRules { : undefined; this.epSquares = [epSq]; } - // Search for king and rooks positions: - this.scanKingsRooks(fen); + // Search for kings positions: + this.scanKings(fen); } ///////////////////// @@ -459,7 +521,7 @@ export const ChessRules = class ChessRules { return { x: 8, y: 8 }; } - // Color of thing on suqare (i,j). 'undefined' if square is empty + // Color of thing on square (i,j). 'undefined' if square is empty getColor(i, j) { return this.board[i][j].charAt(0); } @@ -535,7 +597,7 @@ export const ChessRules = class ChessRules { //////////////////// // MOVES GENERATION - // All possible moves from selected square (assumption: color is OK) + // All possible moves from selected square getPotentialMovesFrom([x, y]) { switch (this.getPiece(x, y)) { case V.PAWN: @@ -557,21 +619,23 @@ export const ChessRules = class ChessRules { // Build a regular move from its initial and destination squares. // tr: transformation getBasicMove([sx, sy], [ex, ey], tr) { + const initColor = this.getColor(sx, sy); + const initPiece = this.getPiece(sx, sy); let mv = new Move({ appear: [ new PiPo({ x: ex, y: ey, - c: tr ? tr.c : this.getColor(sx, sy), - p: tr ? tr.p : this.getPiece(sx, sy) + c: tr ? tr.c : initColor, + p: tr ? tr.p : initPiece }) ], vanish: [ new PiPo({ x: sx, y: sy, - c: this.getColor(sx, sy), - p: this.getPiece(sx, sy) + c: initColor, + p: initPiece }) ] }); @@ -587,6 +651,7 @@ export const ChessRules = class ChessRules { }) ); } + return mv; } @@ -599,7 +664,7 @@ export const ChessRules = class ChessRules { let j = y + step[1]; while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { moves.push(this.getBasicMove([x, y], [i, j])); - if (oneStep !== undefined) continue outerLoop; + if (oneStep) continue outerLoop; i += step[0]; j += step[1]; } @@ -609,83 +674,120 @@ export const ChessRules = class ChessRules { return moves; } + // Special case of en-passant captures: treated separately + getEnpassantCaptures([x, y], shiftX) { + const Lep = this.epSquares.length; + const epSquare = this.epSquares[Lep - 1]; //always at least one element + let enpassantMove = null; + if ( + !!epSquare && + epSquare.x == x + shiftX && + Math.abs(epSquare.y - y) == 1 + ) { + enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]); + enpassantMove.vanish.push({ + x: x, + y: epSquare.y, + // Captured piece is usually a pawn, but next line seems harmless + p: this.getPiece(x, epSquare.y), + c: this.getColor(x, epSquare.y) + }); + } + return !!enpassantMove ? [enpassantMove] : []; + } + + // Consider all potential promotions: + addPawnMoves([x1, y1], [x2, y2], moves, promotions) { + let finalPieces = [V.PAWN]; + const color = this.turn; + const lastRank = (color == "w" ? 0 : V.size.x - 1); + if (x2 == lastRank) { + // promotions arg: special override for Hiddenqueen variant + if (!!promotions) finalPieces = promotions; + else if (!!V.PawnSpecs.promotions) + finalPieces = V.PawnSpecs.promotions; + } + let tr = null; + for (let piece of finalPieces) { + tr = (piece != V.PAWN ? { c: color, p: piece } : null); + moves.push(this.getBasicMove([x1, y1], [x2, y2], tr)); + } + } + // What are the pawn moves from square x,y ? - getPotentialPawnMoves([x, y]) { + getPotentialPawnMoves([x, y], promotions) { const color = this.turn; - let moves = []; const [sizeX, sizeY] = [V.size.x, V.size.y]; - 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 - - // NOTE: next condition is generally true (no pawn on last rank) - if (x + shiftX >= 0 && x + shiftX < sizeX) { - 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) { - 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 * shiftX, y])); + const pawnShiftX = V.PawnSpecs.directions[color]; + const firstRank = (color == "w" ? sizeX - 1 : 0); + const startRank = (color == "w" ? sizeX - 2 : 1); + + // Pawn movements in shiftX direction: + const getPawnMoves = (shiftX) => { + let moves = []; + // NOTE: next condition is generally true (no pawn on last rank) + if (x + shiftX >= 0 && x + shiftX < sizeX) { + if (this.board[x + shiftX][y] == V.EMPTY) { + // One square forward + this.addPawnMoves([x, y], [x + shiftX, y], moves, promotions); + // Next condition because pawns on 1st rank can generally jump + if ( + V.PawnSpecs.twoSquares && + [startRank, firstRank].includes(x) && + this.board[x + 2 * shiftX][y] == V.EMPTY + ) { + // Two squares jump + moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y])); + } } - } - // Captures - for (let shiftY of [-1, 1]) { - if ( - y + shiftY >= 0 && - y + shiftY < sizeY && - this.board[x + shiftX][y + shiftY] != V.EMPTY && - this.canTake([x, y], [x + shiftX, y + shiftY]) - ) { - for (let piece of finalPieces) { - moves.push( - this.getBasicMove([x, y], [x + shiftX, y + shiftY], { - c: pawnColor, - p: piece - }) - ); + // Captures + if (V.PawnSpecs.canCapture) { + for (let shiftY of [-1, 1]) { + if ( + y + shiftY >= 0 && + y + shiftY < sizeY + ) { + if ( + this.board[x + shiftX][y + shiftY] != V.EMPTY && + this.canTake([x, y], [x + shiftX, y + shiftY]) + ) { + this.addPawnMoves( + [x, y], [x + shiftX, y + shiftY], + moves, promotions + ); + } + if ( + V.PawnSpecs.captureBackward && + x - shiftX >= 0 && x - shiftX < V.size.x && + this.board[x - shiftX][y + shiftY] != V.EMPTY && + this.canTake([x, y], [x - shiftX, y + shiftY]) + ) { + this.addPawnMoves( + [x, y], [x + shiftX, y + shiftY], + moves, promotions + ); + } + } } } } + return moves; } + let pMoves = getPawnMoves(pawnShiftX); + if (V.PawnSpecs.bidirectional) + pMoves = pMoves.concat(getPawnMoves(-pawnShiftX)); + if (V.HasEnpassant) { - // 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); - } + // NOTE: backward en-passant captures are not considered + // because no rules define them (for now). + Array.prototype.push.apply( + pMoves, + this.getEnpassantCaptures([x, y], pawnShiftX) + ); } - return moves; + return pMoves; } // What are the rook moves from square x,y ? @@ -719,10 +821,12 @@ export const ChessRules = class ChessRules { V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep" ); - return moves.concat(this.getCastleMoves(sq)); + if (V.HasCastle) moves = moves.concat(this.getCastleMoves(sq)); + return moves; } - getCastleMoves([x, y]) { + // "castleInCheck" arg to let some variants castle under check + getCastleMoves([x, y], castleInCheck) { const c = this.getColor(x, y); if (x != (c == "w" ? V.size.x - 1 : 0) || y != this.INIT_COL_KING[c]) return []; //x isn't first rank, or king has moved (shortcut) @@ -741,8 +845,15 @@ export const ChessRules = class ChessRules { castleSide < 2; castleSide++ //large, then small ) { - if (!this.castleFlags[c][castleSide]) continue; - // If this code is reached, rooks and king are on initial position + if (this.castleFlags[c][castleSide] >= V.size.y) continue; + // If this code is reached, rook and king are on initial position + + // NOTE: in some variants this is not a rook, but let's keep variable name + const rookPos = this.castleFlags[c][castleSide]; + const castlingPiece = this.getPiece(x, rookPos); + if (this.getColor(x, rookPos) != c) + // Rook is here but changed color (see Benedict) + continue; // Nothing on the path of the king ? (and no checks) const finDist = finalSquares[castleSide][0] - y; @@ -750,11 +861,11 @@ export const ChessRules = class ChessRules { i = y; do { if ( - this.isAttacked([x, i], [oppCol]) || + (!castleInCheck && 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)))) + ![V.KING, castlingPiece].includes(this.getPiece(x, i)))) ) { continue castlingCheck; } @@ -763,10 +874,9 @@ export const ChessRules = class ChessRules { // Nothing on the path to the rook? step = castleSide == 0 ? -1 : 1; - for (i = y + step; i != this.INIT_COL_ROOK[c][castleSide]; i += step) { + for (i = y + step; i != rookPos; i += step) { if (this.board[x][i] != V.EMPTY) continue castlingCheck; } - const rookPos = this.INIT_COL_ROOK[c][castleSide]; // Nothing on final squares, except maybe king and castling rook? for (i = 0; i < 2; i++) { @@ -784,11 +894,11 @@ export const ChessRules = class ChessRules { new Move({ appear: [ new PiPo({ x: x, y: finalSquares[castleSide][0], p: V.KING, c: c }), - new PiPo({ x: x, y: finalSquares[castleSide][1], p: V.ROOK, c: c }) + new PiPo({ x: x, y: finalSquares[castleSide][1], p: castlingPiece, c: c }) ], vanish: [ new PiPo({ x: x, y: y, p: V.KING, c: c }), - new PiPo({ x: x, y: rookPos, p: V.ROOK, c: c }) + new PiPo({ x: x, y: rookPos, p: castlingPiece, c: c }) ], end: Math.abs(y - rookPos) <= 2 @@ -825,12 +935,10 @@ export const ChessRules = class ChessRules { // (for engine and game end) getAllValidMoves() { const color = this.turn; - const oppCol = V.GetOppCol(color); let potentialMoves = []; for (let i = 0; i < V.size.x; i++) { for (let j = 0; j < V.size.y; j++) { - // Next condition "!= oppCol" to work with checkered variant - if (this.board[i][j] != V.EMPTY && this.getColor(i, j) != oppCol) { + if (this.getColor(i, j) == color) { Array.prototype.push.apply( potentialMoves, this.getPotentialMovesFrom([i, j]) @@ -844,10 +952,9 @@ export const ChessRules = class ChessRules { // Stop at the first move found atLeastOneMove() { const color = this.turn; - const oppCol = V.GetOppCol(color); for (let i = 0; i < V.size.x; i++) { for (let j = 0; j < V.size.y; j++) { - if (this.board[i][j] != V.EMPTY && this.getColor(i, j) != oppCol) { + if (this.getColor(i, j) == color) { const moves = this.getPotentialMovesFrom([i, j]); if (moves.length > 0) { for (let k = 0; k < moves.length; k++) { @@ -860,104 +967,102 @@ export const ChessRules = class ChessRules { return false; } - // Check if pieces of color in 'colors' are attacking (king) on square x,y - isAttacked(sq, colors) { + // Check if pieces of given color are attacking (king) on square x,y + isAttacked(sq, color) { return ( - this.isAttackedByPawn(sq, colors) || - this.isAttackedByRook(sq, colors) || - this.isAttackedByKnight(sq, colors) || - this.isAttackedByBishop(sq, colors) || - this.isAttackedByQueen(sq, colors) || - this.isAttackedByKing(sq, colors) + this.isAttackedByPawn(sq, color) || + this.isAttackedByRook(sq, color) || + this.isAttackedByKnight(sq, color) || + this.isAttackedByBishop(sq, color) || + this.isAttackedByQueen(sq, color) || + this.isAttackedByKing(sq, color) ); } - // Is square x,y attacked by 'colors' pawns ? - isAttackedByPawn([x, y], colors) { - for (let c of colors) { - let pawnShift = c == "w" ? 1 : -1; - if (x + pawnShift >= 0 && x + pawnShift < V.size.x) { - for (let i of [-1, 1]) { - if ( - y + i >= 0 && - y + i < V.size.y && - this.getPiece(x + pawnShift, y + i) == V.PAWN && - this.getColor(x + pawnShift, y + i) == c - ) { - return true; - } + // Generic method for non-pawn pieces ("sliding or jumping"): + // is x,y attacked by a piece of given color ? + isAttackedBySlideNJump([x, y], color, piece, steps, oneStep) { + for (let step of steps) { + let rx = x + step[0], + ry = y + step[1]; + while (V.OnBoard(rx, ry) && this.board[rx][ry] == V.EMPTY && !oneStep) { + rx += step[0]; + ry += step[1]; + } + if ( + V.OnBoard(rx, ry) && + this.getPiece(rx, ry) == piece && + this.getColor(rx, ry) == color + ) { + return true; + } + } + return false; + } + + // Is square x,y attacked by 'color' pawns ? + isAttackedByPawn([x, y], color) { + const pawnShift = (color == "w" ? 1 : -1); + if (x + pawnShift >= 0 && x + pawnShift < V.size.x) { + for (let i of [-1, 1]) { + if ( + y + i >= 0 && + y + i < V.size.y && + this.getPiece(x + pawnShift, y + i) == V.PAWN && + this.getColor(x + pawnShift, y + i) == color + ) { + return true; } } } return false; } - // Is square x,y attacked by 'colors' rooks ? - isAttackedByRook(sq, colors) { - return this.isAttackedBySlideNJump(sq, colors, V.ROOK, V.steps[V.ROOK]); + // Is square x,y attacked by 'color' rooks ? + isAttackedByRook(sq, color) { + return this.isAttackedBySlideNJump(sq, color, V.ROOK, V.steps[V.ROOK]); } - // Is square x,y attacked by 'colors' knights ? - isAttackedByKnight(sq, colors) { + // Is square x,y attacked by 'color' knights ? + isAttackedByKnight(sq, color) { return this.isAttackedBySlideNJump( sq, - colors, + color, V.KNIGHT, V.steps[V.KNIGHT], "oneStep" ); } - // Is square x,y attacked by 'colors' bishops ? - isAttackedByBishop(sq, colors) { - return this.isAttackedBySlideNJump(sq, colors, V.BISHOP, V.steps[V.BISHOP]); + // Is square x,y attacked by 'color' bishops ? + isAttackedByBishop(sq, color) { + return this.isAttackedBySlideNJump(sq, color, V.BISHOP, V.steps[V.BISHOP]); } - // Is square x,y attacked by 'colors' queens ? - isAttackedByQueen(sq, colors) { + // Is square x,y attacked by 'color' queens ? + isAttackedByQueen(sq, color) { return this.isAttackedBySlideNJump( sq, - colors, + color, V.QUEEN, V.steps[V.ROOK].concat(V.steps[V.BISHOP]) ); } - // Is square x,y attacked by 'colors' king(s) ? - isAttackedByKing(sq, colors) { + // Is square x,y attacked by 'color' king(s) ? + isAttackedByKing(sq, color) { return this.isAttackedBySlideNJump( sq, - colors, + color, V.KING, V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep" ); } - // Generic method for non-pawn pieces ("sliding or jumping"): - // is x,y attacked by a piece of color in array 'colors' ? - isAttackedBySlideNJump([x, y], colors, piece, steps, oneStep) { - for (let step of steps) { - let rx = x + step[0], - ry = y + step[1]; - while (V.OnBoard(rx, ry) && this.board[rx][ry] == V.EMPTY && !oneStep) { - rx += step[0]; - ry += step[1]; - } - if ( - V.OnBoard(rx, ry) && - this.getPiece(rx, ry) === piece && - colors.includes(this.getColor(rx, ry)) - ) { - return true; - } - } - return false; - } - // Is color under check after his move ? underCheck(color) { - return this.isAttacked(this.kingPos[color], [V.GetOppCol(color)]); + return this.isAttacked(this.kingPos[color], V.GetOppCol(color)); } ///////////////// @@ -974,106 +1079,106 @@ export const ChessRules = class ChessRules { for (let psq of move.vanish) board[psq.x][psq.y] = psq.c + psq.p; } + prePlay() {} + + play(move) { + // DEBUG: +// if (!this.states) this.states = []; +// const stateFen = this.getFen() + JSON.stringify(this.kingPos); +// this.states.push(stateFen); + + this.prePlay(move); + 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 = V.GetOppCol(this.turn); + this.movesCount++; + this.postPlay(move); + } + + updateCastleFlags(move, piece) { + const c = V.GetOppCol(this.turn); + const firstRank = (c == "w" ? V.size.x - 1 : 0); + // Update castling flags if rooks are moved + const oppCol = V.GetOppCol(c); + const oppFirstRank = V.size.x - 1 - firstRank; + if (piece == V.KING && move.appear.length > 0) + this.castleFlags[c] = [V.size.y, V.size.y]; + else if ( + move.start.x == firstRank && //our rook moves? + this.castleFlags[c].includes(move.start.y) + ) { + const flagIdx = (move.start.y == this.castleFlags[c][0] ? 0 : 1); + this.castleFlags[c][flagIdx] = V.size.y; + } + // NOTE: not "else if" because a rook could take an opposing rook + if ( + move.end.x == oppFirstRank && //we took opponent rook? + this.castleFlags[oppCol].includes(move.end.y) + ) { + const flagIdx = (move.end.y == this.castleFlags[oppCol][0] ? 0 : 1); + this.castleFlags[oppCol][flagIdx] = V.size.y; + } + } + // After move is played, update variables + flags - updateVariables(move) { + postPlay(move) { + const c = V.GetOppCol(this.turn); let piece = undefined; - // TODO: update variables before move is played, and just use this.turn ? - // (doesn't work in general, think MarseilleChess) - let c = undefined; - if (move.vanish.length >= 1) { + if (move.vanish.length >= 1) // Usual case, something is moved piece = move.vanish[0].p; - c = move.vanish[0].c; - } else { + else // Crazyhouse-like variants piece = move.appear[0].p; - c = move.appear[0].c; - } - if (!['w','b'].includes(c)) { - // Checkered, for example - c = V.GetOppCol(this.turn); - } - const firstRank = c == "w" ? V.size.x - 1 : 0; // Update king position + flags if (piece == V.KING && move.appear.length > 0) { this.kingPos[c][0] = move.appear[0].x; this.kingPos[c][1] = move.appear[0].y; - if (V.HasFlags) this.castleFlags[c] = [false, false]; return; } - if (V.HasFlags) { - // Update castling flags if rooks are moved - const oppCol = V.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; - } - } + if (V.HasCastle) this.updateCastleFlags(move, piece); } - // After move is undo-ed *and flags resetted*, un-update other variables - // TODO: more symmetry, by storing flags increment in move (?!) - unupdateVariables(move) { - // (Potentially) Reset king position - const c = this.getColor(move.start.x, move.start.y); - if (this.getPiece(move.start.x, move.start.y) == V.KING) - this.kingPos[c] = [move.start.x, move.start.y]; - } - - play(move) { - // DEBUG: -// if (!this.states) this.states = []; -// const stateFen = this.getBaseFen() + this.getTurnFen() + this.getFlagsFen(); -// this.states.push(stateFen); - - 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 = V.GetOppCol(this.turn); - this.movesCount++; - this.updateVariables(move); - } + preUndo() {} undo(move) { + this.preUndo(move); if (V.HasEnpassant) this.epSquares.pop(); if (V.HasFlags) this.disaggregateFlags(JSON.parse(move.flags)); V.UndoOnBoard(this.board, move); this.turn = V.GetOppCol(this.turn); this.movesCount--; - this.unupdateVariables(move); + this.postUndo(move); // DEBUG: -// const stateFen = this.getBaseFen() + this.getTurnFen() + this.getFlagsFen(); +// const stateFen = this.getFen() + JSON.stringify(this.kingPos); // if (stateFen != this.states[this.states.length-1]) debugger; // this.states.pop(); } + // After move is undo-ed *and flags resetted*, un-update other variables + // TODO: more symmetry, by storing flags increment in move (?!) + postUndo(move) { + // (Potentially) Reset king position + const c = this.getColor(move.start.x, move.start.y); + if (this.getPiece(move.start.x, move.start.y) == V.KING) + this.kingPos[c] = [move.start.x, move.start.y]; + } + /////////////// // END OF GAME // What is the score ? (Interesting if game is over) getCurrentScore() { - if (this.atLeastOneMove()) - return "*"; - + if (this.atLeastOneMove()) return "*"; // Game over const color = this.turn; // No valid move: stalemate or checkmate? - if (!this.isAttacked(this.kingPos[color], [V.GetOppCol(color)])) - return "1/2"; + if (!this.underCheck(color)) return "1/2"; // OK, checkmate - return color == "w" ? "0-1" : "1-0"; + return (color == "w" ? "0-1" : "1-0"); } /////////////// @@ -1101,70 +1206,64 @@ export const ChessRules = class ChessRules { return V.INFINITY; } - // Search depth: 2 for high branching factor, 4 for small (Loser chess, eg.) + // Search depth: 1,2 for high branching factor, 4 for small (Loser chess, eg.) static get SEARCH_DEPTH() { return 3; } - // NOTE: works also for extinction chess because depth is 3... getComputerMove() { const maxeval = V.INFINITY; const color = this.turn; - // 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"); + let moves1 = this.getAllValidMoves(); + if (moves1.length == 0) - //TODO: this situation should not happen + // TODO: this situation should not happen return null; - // Can I mate in 1 ? (for Magnetic & Extinction) - for (let i of shuffle(ArrayFun.range(moves1.length))) { + // Rank moves using a min-max at depth 2 (if search_depth >= 2!) + for (let i = 0; i < moves1.length; i++) { this.play(moves1[i]); - let finish = Math.abs(this.evalPosition()) >= V.THRESHOLD_MATE; - if (!finish) { - const score = this.getCurrentScore(); - if (["1-0", "0-1"].includes(score)) finish = true; + const score1 = this.getCurrentScore(); + if (score1 != "*") { + moves1[i].eval = + score1 == "1/2" + ? 0 + : (score1 == "1-0" ? 1 : -1) * maxeval; + } + if (V.SEARCH_DEPTH == 1 || score1 != "*") { + if (!moves1[i].eval) moves1[i].eval = this.evalPosition(); + this.undo(moves1[i]); + continue; } - this.undo(moves1[i]); - if (finish) return moves1[i]; - } - - // Rank moves using a min-max at depth 2 - for (let i = 0; i < moves1.length; i++) { // Initial self evaluation is very low: "I'm checkmated" moves1[i].eval = (color == "w" ? -1 : 1) * maxeval; - this.play(moves1[i]); - const score1 = this.getCurrentScore(); - let eval2 = undefined; - if (score1 == "*") { - // 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++) { - this.play(moves2[j]); - const score2 = this.getCurrentScore(); - let evalPos = 0; //1/2 value - switch (score2) { - case "*": - evalPos = this.evalPosition(); - break; - case "1-0": - evalPos = maxeval; - break; - case "0-1": - evalPos = -maxeval; - break; - } - if ( - (color == "w" && evalPos < eval2) || - (color == "b" && evalPos > eval2) - ) { - eval2 = evalPos; - } - this.undo(moves2[j]); + // Initial enemy evaluation is very low too, for him + let eval2 = (color == "w" ? 1 : -1) * maxeval; + // Second half-move: + let moves2 = this.getAllValidMoves(); + for (let j = 0; j < moves2.length; j++) { + this.play(moves2[j]); + const score2 = this.getCurrentScore(); + let evalPos = 0; //1/2 value + switch (score2) { + case "*": + evalPos = this.evalPosition(); + break; + case "1-0": + evalPos = maxeval; + break; + case "0-1": + evalPos = -maxeval; + break; + } + if ( + (color == "w" && evalPos < eval2) || + (color == "b" && evalPos > eval2) + ) { + eval2 = evalPos; } - } else eval2 = score1 == "1/2" ? 0 : (score1 == "1-0" ? 1 : -1) * maxeval; + this.undo(moves2[j]); + } if ( (color == "w" && eval2 > moves1[i].eval) || (color == "b" && eval2 < moves1[i].eval) @@ -1176,20 +1275,11 @@ export const ChessRules = class ChessRules { moves1.sort((a, b) => { return (color == "w" ? 1 : -1) * (b.eval - a.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[candidates[randInt(candidates.length)]]; +// console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; })); // Skip depth 3+ if we found a checkmate (or if we are checkmated in 1...) if (V.SEARCH_DEPTH >= 3 && Math.abs(moves1[0].eval) < V.THRESHOLD_MATE) { - // From here, depth >= 3: may take a while, so we control time - const timeStart = Date.now(); for (let i = 0; i < moves1.length; i++) { - 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 = @@ -1200,12 +1290,11 @@ export const ChessRules = class ChessRules { 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]; })); + } - candidates = [0]; - for (let j = 1; j < moves1.length && moves1[j].eval == moves1[0].eval; j++) - candidates.push(j); + let candidates = [0]; + for (let i = 1; i < moves1.length && moves1[i].eval == moves1[0].eval; i++) + candidates.push(i); return moves1[candidates[randInt(candidates.length)]]; } @@ -1216,7 +1305,7 @@ export const ChessRules = class ChessRules { if (score != "*") return score == "1/2" ? 0 : (score == "1-0" ? 1 : -1) * maxeval; if (depth == 0) return this.evalPosition(); - const moves = this.getAllValidMoves("computer"); + const moves = this.getAllValidMoves(); let v = color == "w" ? -maxeval : maxeval; if (color == "w") { for (let i = 0; i < moves.length; i++) { @@ -1226,8 +1315,9 @@ export const ChessRules = class ChessRules { alpha = Math.max(alpha, v); if (alpha >= beta) break; //beta cutoff } - } //color=="b" + } else { + // color=="b" for (let i = 0; i < moves.length; i++) { this.play(moves[i]); v = Math.min(v, this.alphabeta(depth - 1, alpha, beta)); @@ -1261,7 +1351,7 @@ export const ChessRules = class ChessRules { // TODO: un-ambiguous notation (switch on piece type, check directions...) getNotation(move) { if (move.appear.length == 2 && move.appear[0].p == V.KING) - //castle + // Castle return move.end.y < move.start.y ? "0-0-0" : "0-0"; // Translate final square