| 1 | // TODO: debug, and forbid self-capture of king. |
| 2 | |
| 3 | import { ChessRules } from "@/base_rules"; |
| 4 | import { randInt } from "@/utils/alea"; |
| 5 | |
| 6 | export class SynchroneRules extends ChessRules { |
| 7 | static get CanAnalyze() { |
| 8 | return true; //false; |
| 9 | } |
| 10 | |
| 11 | static get ShowMoves() { |
| 12 | return "byrow"; |
| 13 | } |
| 14 | |
| 15 | static IsGoodFen(fen) { |
| 16 | if (!ChessRules.IsGoodFen(fen)) return false; |
| 17 | const fenParsed = V.ParseFen(fen); |
| 18 | // 5) Check whiteMove |
| 19 | if ( |
| 20 | ( |
| 21 | fenParsed.turn == "w" && |
| 22 | // NOTE: do not check really JSON stringified move... |
| 23 | (!fenParsed.whiteMove || fenParsed.whiteMove == "-") |
| 24 | ) |
| 25 | || |
| 26 | (fenParsed.turn == "b" && fenParsed.whiteMove != "-") |
| 27 | ) { |
| 28 | return false; |
| 29 | } |
| 30 | return true; |
| 31 | } |
| 32 | |
| 33 | static IsGoodEnpassant(enpassant) { |
| 34 | const epArray = enpassant.split(","); |
| 35 | if (![2, 3].includes(epArray.length)) return false; |
| 36 | epArray.forEach(epsq => { |
| 37 | if (epsq != "-") { |
| 38 | const ep = V.SquareToCoords(epsq); |
| 39 | if (isNaN(ep.x) || !V.OnBoard(ep)) return false; |
| 40 | } |
| 41 | }); |
| 42 | return true; |
| 43 | } |
| 44 | |
| 45 | static ParseFen(fen) { |
| 46 | const fenParts = fen.split(" "); |
| 47 | return Object.assign( |
| 48 | ChessRules.ParseFen(fen), |
| 49 | { whiteMove: fenParts[5] } |
| 50 | ); |
| 51 | } |
| 52 | |
| 53 | static GenRandInitFen(randomness) { |
| 54 | return ChessRules.GenRandInitFen(randomness).slice(0, -1) + "-,- -"; |
| 55 | } |
| 56 | |
| 57 | getFen() { |
| 58 | return super.getFen() + " " + this.getWhitemoveFen(); |
| 59 | } |
| 60 | |
| 61 | getFenForRepeat() { |
| 62 | return super.getFenForRepeat() + "_" + this.getWhitemoveFen(); |
| 63 | } |
| 64 | |
| 65 | setOtherVariables(fen) { |
| 66 | const parsedFen = V.ParseFen(fen); |
| 67 | this.setFlags(parsedFen.flags); |
| 68 | const epArray = parsedFen.enpassant.split(","); |
| 69 | this.epSquares = []; |
| 70 | epArray.forEach(epsq => this.epSquares.push(this.getEpSquare(epsq))); |
| 71 | super.scanKings(fen); |
| 72 | // Also init whiteMove |
| 73 | this.whiteMove = |
| 74 | parsedFen.whiteMove != "-" |
| 75 | ? JSON.parse(parsedFen.whiteMove) |
| 76 | : null; |
| 77 | } |
| 78 | |
| 79 | // After undo(): no need to re-set INIT_COL_KING |
| 80 | scanKings() { |
| 81 | this.kingPos = { w: [-1, -1], b: [-1, -1] }; |
| 82 | for (let i = 0; i < V.size.x; i++) { |
| 83 | for (let j = 0; j < V.size.y; j++) { |
| 84 | if (this.getPiece(i, j) == V.KING) |
| 85 | this.kingPos[this.getColor(i, j)] = [i, j]; |
| 86 | } |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | getEnpassantFen() { |
| 91 | const L = this.epSquares.length; |
| 92 | let res = ""; |
| 93 | const start = L - 2 - (this.turn == 'b' ? 1 : 0); |
| 94 | for (let i=start; i < L; i++) { |
| 95 | if (!this.epSquares[i]) res += "-,"; |
| 96 | else res += V.CoordsToSquare(this.epSquares[i]) + ","; |
| 97 | } |
| 98 | return res.slice(0, -1); |
| 99 | } |
| 100 | |
| 101 | getWhitemoveFen() { |
| 102 | if (!this.whiteMove) return "-"; |
| 103 | return JSON.stringify({ |
| 104 | start: this.whiteMove.start, |
| 105 | end: this.whiteMove.end, |
| 106 | appear: this.whiteMove.appear, |
| 107 | vanish: this.whiteMove.vanish |
| 108 | }); |
| 109 | } |
| 110 | |
| 111 | // NOTE: lazy unefficient implementation (for now. TODO?) |
| 112 | getPossibleMovesFrom([x, y]) { |
| 113 | const moves = this.getAllValidMoves(); |
| 114 | return moves.filter(m => { |
| 115 | return m.start.x == x && m.start.y == y; |
| 116 | }); |
| 117 | } |
| 118 | |
| 119 | getCaptures(x, y) { |
| 120 | const color = this.turn; |
| 121 | const sliderAttack = (xx, yy, allowedSteps) => { |
| 122 | const deltaX = xx - x, |
| 123 | absDeltaX = Math.abs(deltaX); |
| 124 | const deltaY = yy - y, |
| 125 | absDeltaY = Math.abs(deltaY); |
| 126 | const step = [ deltaX / absDeltaX || 0, deltaY / absDeltaY || 0 ]; |
| 127 | if ( |
| 128 | // Check that the step is a priori valid: |
| 129 | (absDeltaX != absDeltaY && deltaX != 0 && deltaY != 0) || |
| 130 | allowedSteps.every(st => st[0] != step[0] || st[1] != step[1]) |
| 131 | ) { |
| 132 | return null; |
| 133 | } |
| 134 | let sq = [ x + step[0], y + step[1] ]; |
| 135 | while (sq[0] != xx || sq[1] != yy) { |
| 136 | // NOTE: no need to check OnBoard in this special case |
| 137 | if (this.board[sq[0]][sq[1]] != V.EMPTY) return null; |
| 138 | sq[0] += step[0]; |
| 139 | sq[1] += step[1]; |
| 140 | } |
| 141 | return this.getBasicMove([xx, yy], [x, y]); |
| 142 | }; |
| 143 | // Can I take on the square [x, y] ? |
| 144 | // If yes, return the (list of) capturing move(s) |
| 145 | let moves = []; |
| 146 | for (let i=0; i<8; i++) { |
| 147 | for (let j=0; j<8; j++) { |
| 148 | if (this.getColor(i, j) == color) { |
| 149 | switch (this.getPiece(i, j)) { |
| 150 | case V.PAWN: { |
| 151 | // Pushed pawns move as enemy pawns |
| 152 | const shift = (color == 'w' ? 1 : -1); |
| 153 | if (x + shift == i && Math.abs(y - j) == 1) |
| 154 | moves.push(this.getBasicMove([i, j], [x, y])); |
| 155 | break; |
| 156 | } |
| 157 | case V.KNIGHT: { |
| 158 | const deltaX = Math.abs(i - x); |
| 159 | const deltaY = Math.abs(j - y); |
| 160 | if ( |
| 161 | deltaX + deltaY == 3 && |
| 162 | [1, 2].includes(deltaX) && |
| 163 | [1, 2].includes(deltaY) |
| 164 | ) { |
| 165 | moves.push(this.getBasicMove([i, j], [x, y])); |
| 166 | } |
| 167 | break; |
| 168 | } |
| 169 | case V.KING: |
| 170 | if (Math.abs(i - x) <= 1 && Math.abs(j - y) <= 1) |
| 171 | moves.push(this.getBasicMove([i, j], [x, y])); |
| 172 | break; |
| 173 | case V.ROOK: { |
| 174 | const mv = sliderAttack(i, j, V.steps[V.ROOK]); |
| 175 | if (!!mv) moves.push(mv); |
| 176 | break; |
| 177 | } |
| 178 | case V.BISHOP: { |
| 179 | const mv = sliderAttack(i, j, V.steps[V.BISHOP]); |
| 180 | if (!!mv) moves.push(mv); |
| 181 | break; |
| 182 | } |
| 183 | case V.QUEEN: { |
| 184 | const mv = sliderAttack( |
| 185 | i, j, V.steps[V.ROOK].concat(V.steps[V.BISHOP])); |
| 186 | if (!!mv) moves.push(mv); |
| 187 | break; |
| 188 | } |
| 189 | } |
| 190 | } |
| 191 | } |
| 192 | } |
| 193 | return this.filterValid(moves); |
| 194 | } |
| 195 | |
| 196 | getAllValidMoves() { |
| 197 | const color = this.turn; |
| 198 | // 0) Generate our possible moves |
| 199 | let myMoves = super.getAllValidMoves(); |
| 200 | // Lookup table to quickly decide if a move is already in list: |
| 201 | let moveSet = {}; |
| 202 | const getMoveHash = (move) => { |
| 203 | return ( |
| 204 | "m" + move.start.x + move.start.y + |
| 205 | move.end.x + move.end.y + |
| 206 | // Also use m.appear[0].p for pawn promotions |
| 207 | move.appear[0].p |
| 208 | ); |
| 209 | }; |
| 210 | myMoves.forEach(m => moveSet[getMoveHash(m)] = true); |
| 211 | // 1) Generate all opponent's moves |
| 212 | this.turn = V.GetOppCol(color); |
| 213 | const oppMoves = super.getAllValidMoves(); |
| 214 | this.turn = color; |
| 215 | // 2) Play each opponent's move, and see if captures are possible: |
| 216 | // --> capturing moving unit only (otherwise some issues) |
| 217 | oppMoves.forEach(m => { |
| 218 | V.PlayOnBoard(this.board, m); |
| 219 | // Can I take on [m.end.x, m.end.y] ? |
| 220 | // If yes and not already in list, add it (without the capturing part) |
| 221 | let capturingMoves = this.getCaptures(m.end.x, m.end.y); |
| 222 | capturingMoves.forEach(cm => { |
| 223 | const cmHash = getMoveHash(cm); |
| 224 | if (!moveSet[cmHash]) { |
| 225 | // The captured unit hasn't moved yet, so temporarily cancel capture |
| 226 | cm.vanish.pop(); |
| 227 | // If m is itself a capturing move: then replace by self-capture |
| 228 | if (m.vanish.length == 2) cm.vanish.push(m.vanish[1]); |
| 229 | myMoves.push(cm); |
| 230 | moveSet[cmHash] = true; |
| 231 | } |
| 232 | }); |
| 233 | V.UndoOnBoard(this.board, m); |
| 234 | }); |
| 235 | return myMoves; |
| 236 | } |
| 237 | |
| 238 | filterValid(moves) { |
| 239 | if (moves.length == 0) return []; |
| 240 | // filterValid can be called when it's "not our turn": |
| 241 | const color = moves[0].vanish[0].c; |
| 242 | return moves.filter(m => { |
| 243 | const piece = m.vanish[0].p; |
| 244 | if (piece == V.KING) { |
| 245 | this.kingPos[color][0] = m.appear[0].x; |
| 246 | this.kingPos[color][1] = m.appear[0].y; |
| 247 | } |
| 248 | V.PlayOnBoard(this.board, m); |
| 249 | let res = !this.underCheck(color); |
| 250 | V.UndoOnBoard(this.board, m); |
| 251 | if (piece == V.KING) this.kingPos[color] = [m.start.x, m.start.y]; |
| 252 | return res; |
| 253 | }); |
| 254 | } |
| 255 | |
| 256 | atLeastOneMove(color) { |
| 257 | const curTurn = this.turn; |
| 258 | this.turn = color; |
| 259 | const res = super.atLeastOneMove(); |
| 260 | this.turn = curTurn; |
| 261 | return res; |
| 262 | } |
| 263 | |
| 264 | // White and black (partial) moves were played: merge |
| 265 | resolveSynchroneMove(move) { |
| 266 | const m1 = this.whiteMove; |
| 267 | const m2 = move; |
| 268 | // For PlayOnBoard (no need for start / end, irrelevant) |
| 269 | let smove = { |
| 270 | appear: [], |
| 271 | vanish: [ |
| 272 | m1.vanish[0], |
| 273 | m2.vanish[0] |
| 274 | ] |
| 275 | }; |
| 276 | if ((m1.end.x != m2.end.x) || (m1.end.y != m2.end.y)) { |
| 277 | // Easy case: two independant moves (which may (self-)capture) |
| 278 | smove.appear.push(m1.appear[0]); |
| 279 | smove.appear.push(m2.appear[0]); |
| 280 | // "Captured" pieces may have moved: |
| 281 | if ( |
| 282 | m1.vanish.length == 2 && |
| 283 | ( |
| 284 | m2.end.x != m1.vanish[1].x || |
| 285 | m2.end.y != m1.vanish[1].y |
| 286 | ) |
| 287 | ) { |
| 288 | smove.vanish.push(m1.vanish[1]); |
| 289 | } |
| 290 | if ( |
| 291 | m2.vanish.length == 2 && |
| 292 | ( |
| 293 | m1.end.x != m2.vanish[1].x || |
| 294 | m1.end.y != m2.vanish[1].y |
| 295 | ) |
| 296 | ) { |
| 297 | smove.vanish.push(m2.vanish[1]); |
| 298 | } |
| 299 | } else { |
| 300 | // Collision: |
| 301 | if (m1.vanish.length == 1 && m2.vanish.length == 1) { |
| 302 | // Easy case: both disappear except if one is a king |
| 303 | const p1 = m1.vanish[0].p; |
| 304 | const p2 = m2.vanish[0].p; |
| 305 | if ([p1, p2].includes(V.KING)) { |
| 306 | smove.appear.push({ |
| 307 | x: m1.end.x, |
| 308 | y: m1.end.y, |
| 309 | p: V.KING, |
| 310 | c: (p1 == V.KING ? 'w' : 'b') |
| 311 | }); |
| 312 | } |
| 313 | } else { |
| 314 | // One move is a self-capture and the other a normal capture: |
| 315 | // only the self-capture appears |
| 316 | console.log(m1); |
| 317 | console.log(m2); |
| 318 | const selfCaptureMove = |
| 319 | m1.vanish[1].c == m1.vanish[0].c |
| 320 | ? m1 |
| 321 | : m2; |
| 322 | smove.appear.push({ |
| 323 | x: m1.end.x, |
| 324 | y: m1.end.y, |
| 325 | p: selfCaptureMove.appear[0].p, |
| 326 | c: selfCaptureMove.vanish[0].c |
| 327 | }); |
| 328 | } |
| 329 | } |
| 330 | return smove; |
| 331 | } |
| 332 | |
| 333 | play(move) { |
| 334 | move.flags = JSON.stringify(this.aggregateFlags()); //save flags (for undo) |
| 335 | this.epSquares.push(this.getEpSquare(move)); |
| 336 | // Do not play on board (would reveal the move...) |
| 337 | this.turn = V.GetOppCol(this.turn); |
| 338 | this.movesCount++; |
| 339 | this.postPlay(move); |
| 340 | } |
| 341 | |
| 342 | updateCastleFlags(move) { |
| 343 | const firstRank = { 'w': V.size.x - 1, 'b': 0 }; |
| 344 | move.appear.concat(move.vanish).forEach(av => { |
| 345 | for (let c of ['w', 'b']) { |
| 346 | if (av.x == firstRank[c] && this.castleFlags[c].includes(av.y)) { |
| 347 | const flagIdx = (av.y == this.castleFlags[c][0] ? 0 : 1); |
| 348 | this.castleFlags[c][flagIdx] = 8; |
| 349 | } |
| 350 | } |
| 351 | }); |
| 352 | } |
| 353 | |
| 354 | postPlay(move) { |
| 355 | if (this.turn == 'b') { |
| 356 | // NOTE: whiteMove is used read-only, so no need to copy |
| 357 | this.whiteMove = move; |
| 358 | return; |
| 359 | } |
| 360 | |
| 361 | // A full turn just ended: |
| 362 | const smove = this.resolveSynchroneMove(move); |
| 363 | V.PlayOnBoard(this.board, smove); |
| 364 | this.whiteMove = null; |
| 365 | |
| 366 | // Update king position + flags |
| 367 | let kingAppear = { 'w': false, 'b': false }; |
| 368 | for (let i=0; i<smove.appear.length; i++) { |
| 369 | if (smove.appear[i].p == V.KING) { |
| 370 | const c = smove.appear[i].c; |
| 371 | kingAppear[c] = true; |
| 372 | this.kingPos[c][0] = smove.appear[i].x; |
| 373 | this.kingPos[c][1] = smove.appear[i].y; |
| 374 | } |
| 375 | } |
| 376 | for (let i=0; i<smove.vanish.length; i++) { |
| 377 | if (smove.vanish[i].p == V.KING) { |
| 378 | const c = smove.vanish[i].c; |
| 379 | if (!kingAppear[c]) { |
| 380 | this.kingPos[c][0] = -1; |
| 381 | this.kingPos[c][1] = -1; |
| 382 | } |
| 383 | break; |
| 384 | } |
| 385 | } |
| 386 | this.updateCastleFlags(smove); |
| 387 | move.smove = smove; |
| 388 | } |
| 389 | |
| 390 | undo(move) { |
| 391 | this.epSquares.pop(); |
| 392 | this.disaggregateFlags(JSON.parse(move.flags)); |
| 393 | if (this.turn == 'w') |
| 394 | // Back to the middle of the move |
| 395 | V.UndoOnBoard(this.board, move.smove); |
| 396 | this.turn = V.GetOppCol(this.turn); |
| 397 | this.movesCount--; |
| 398 | this.postUndo(move); |
| 399 | } |
| 400 | |
| 401 | postUndo(move) { |
| 402 | if (this.turn == 'w') |
| 403 | // Reset king positions: scan board |
| 404 | this.scanKings(); |
| 405 | } |
| 406 | |
| 407 | getCheckSquares(color) { |
| 408 | if (color == 'b') return []; |
| 409 | let res = []; |
| 410 | if (this.underCheck('w')) |
| 411 | res.push(JSON.parse(JSON.stringify(this.kingPos['w']))); |
| 412 | if (this.underCheck('b')) |
| 413 | res.push(JSON.parse(JSON.stringify(this.kingPos['b']))); |
| 414 | return res; |
| 415 | } |
| 416 | |
| 417 | getCurrentScore() { |
| 418 | if (this.turn == 'b') |
| 419 | // Turn (white + black) not over yet |
| 420 | return "*"; |
| 421 | // Was a king captured? |
| 422 | if (this.kingPos['w'][0] < 0) return "0-1"; |
| 423 | if (this.kingPos['b'][0] < 0) return "1-0"; |
| 424 | const whiteCanMove = this.atLeastOneMove('w'); |
| 425 | const blackCanMove = this.atLeastOneMove('b'); |
| 426 | if (whiteCanMove && blackCanMove) return "*"; |
| 427 | // Game over |
| 428 | const whiteInCheck = this.underCheck('w'); |
| 429 | const blackInCheck = this.underCheck('b'); |
| 430 | if ( |
| 431 | (whiteCanMove && !this.underCheck('b')) || |
| 432 | (blackCanMove && !this.underCheck('w')) |
| 433 | ) { |
| 434 | return "1/2"; |
| 435 | } |
| 436 | // Checkmate: could be mutual |
| 437 | if (!whiteCanMove && !blackCanMove) return "1/2"; |
| 438 | return (whiteCanMove ? "1-0" : "0-1"); |
| 439 | } |
| 440 | |
| 441 | getComputerMove() { |
| 442 | const maxeval = V.INFINITY; |
| 443 | const color = this.turn; |
| 444 | let moves = this.getAllValidMoves(); |
| 445 | if (moves.length == 0) |
| 446 | // TODO: this situation should not happen |
| 447 | return null; |
| 448 | |
| 449 | if (Math.random() < 0.5) |
| 450 | // Return a random move |
| 451 | return moves[randInt(moves.length)]; |
| 452 | |
| 453 | // Rank moves at depth 1: |
| 454 | // try to capture something (not re-capturing) |
| 455 | moves.forEach(m => { |
| 456 | V.PlayOnBoard(this.board, m); |
| 457 | m.eval = this.evalPosition(); |
| 458 | V.UndoOnBoard(this.board, m); |
| 459 | }); |
| 460 | moves.sort((a, b) => { |
| 461 | return (color == "w" ? 1 : -1) * (b.eval - a.eval); |
| 462 | }); |
| 463 | let candidates = [0]; |
| 464 | for (let i = 1; i < moves.length && moves[i].eval == moves[0].eval; i++) |
| 465 | candidates.push(i); |
| 466 | return moves[candidates[randInt(candidates.length)]]; |
| 467 | } |
| 468 | }; |