| 1 | import { ChessRules, PiPo, Move } from "@/base_rules"; |
| 2 | import { ArrayFun } from "@/utils/array"; |
| 3 | import { shuffle } from "@/utils/alea"; |
| 4 | |
| 5 | export class MaximaRules extends ChessRules { |
| 6 | |
| 7 | static get HasFlags() { |
| 8 | return false; |
| 9 | } |
| 10 | |
| 11 | static get HasEnpassant() { |
| 12 | return false; |
| 13 | } |
| 14 | |
| 15 | static get PIECES() { |
| 16 | return ChessRules.PIECES.concat([V.IMMOBILIZER, V.MAGE, V.GUARD]); |
| 17 | } |
| 18 | |
| 19 | getPpath(b) { |
| 20 | if (b[0] == 'x') return "Maxima/nothing"; |
| 21 | if (['m','d','g'].includes(b[1])) |
| 22 | return "Maxima/" + b; |
| 23 | return b; |
| 24 | } |
| 25 | |
| 26 | // For space next to the palaces: |
| 27 | static get NOTHING() { |
| 28 | return "xx"; |
| 29 | } |
| 30 | |
| 31 | static board2fen(b) { |
| 32 | if (b[0] == 'x') return 'x'; |
| 33 | return ChessRules.board2fen(b); |
| 34 | } |
| 35 | |
| 36 | static fen2board(f) { |
| 37 | if (f == 'x') return V.NOTHING; |
| 38 | return ChessRules.fen2board(f); |
| 39 | } |
| 40 | |
| 41 | // TODO: the wall position should be checked too |
| 42 | static IsGoodPosition(position) { |
| 43 | if (position.length == 0) return false; |
| 44 | const rows = position.split("/"); |
| 45 | if (rows.length != V.size.x) return false; |
| 46 | let kings = { "k": 0, "K": 0 }; |
| 47 | for (let row of rows) { |
| 48 | let sumElts = 0; |
| 49 | for (let i = 0; i < row.length; i++) { |
| 50 | if (['K','k'].includes(row[i])) kings[row[i]]++; |
| 51 | if (['x'].concat(V.PIECES).includes(row[i].toLowerCase())) sumElts++; |
| 52 | else { |
| 53 | const num = parseInt(row[i], 10); |
| 54 | if (isNaN(num)) return false; |
| 55 | sumElts += num; |
| 56 | } |
| 57 | } |
| 58 | if (sumElts != V.size.y) return false; |
| 59 | } |
| 60 | if (Object.values(kings).some(v => v != 1)) return false; |
| 61 | return true; |
| 62 | } |
| 63 | |
| 64 | // No castling, but checks, so keep track of kings |
| 65 | setOtherVariables(fen) { |
| 66 | this.kingPos = { w: [-1, -1], b: [-1, -1] }; |
| 67 | const fenParts = fen.split(" "); |
| 68 | const position = fenParts[0].split("/"); |
| 69 | for (let i = 0; i < position.length; i++) { |
| 70 | let k = 0; |
| 71 | for (let j = 0; j < position[i].length; j++) { |
| 72 | switch (position[i].charAt(j)) { |
| 73 | case "k": |
| 74 | this.kingPos["b"] = [i, k]; |
| 75 | break; |
| 76 | case "K": |
| 77 | this.kingPos["w"] = [i, k]; |
| 78 | break; |
| 79 | default: { |
| 80 | const num = parseInt(position[i].charAt(j), 10); |
| 81 | if (!isNaN(num)) k += num - 1; |
| 82 | } |
| 83 | } |
| 84 | k++; |
| 85 | } |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | static get size() { |
| 90 | return { x: 11, y: 8 }; |
| 91 | } |
| 92 | |
| 93 | static OnBoard(x, y) { |
| 94 | return ( |
| 95 | (x >= 1 && x <= 9 && y >= 0 && y <= 7) || |
| 96 | ([3, 4].includes(y) && [0, 10].includes(x)) |
| 97 | ); |
| 98 | } |
| 99 | |
| 100 | static get IMMOBILIZER() { |
| 101 | return "m"; |
| 102 | } |
| 103 | static get MAGE() { |
| 104 | return 'g'; |
| 105 | } |
| 106 | static get GUARD() { |
| 107 | return 'd'; |
| 108 | } |
| 109 | // Although other pieces keep their names here for coding simplicity, |
| 110 | // keep in mind that: |
| 111 | // - a "rook" is a coordinator, capturing by coordinating with the king |
| 112 | // - a "knight" is a long-leaper, capturing as in draughts |
| 113 | // - a "bishop" is a chameleon, capturing as its prey |
| 114 | // - a "queen" is a withdrawer, capturing by moving away from pieces |
| 115 | |
| 116 | // Is piece on square (x,y) immobilized? |
| 117 | isImmobilized([x, y]) { |
| 118 | const piece = this.getPiece(x, y); |
| 119 | if (piece == V.MAGE) |
| 120 | // Mages are not immobilized: |
| 121 | return false; |
| 122 | const oppCol = V.GetOppCol(this.getColor(x, y)); |
| 123 | const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]); |
| 124 | for (let step of adjacentSteps) { |
| 125 | const [i, j] = [x + step[0], y + step[1]]; |
| 126 | if ( |
| 127 | V.OnBoard(i, j) && |
| 128 | this.board[i][j] != V.EMPTY && |
| 129 | this.getColor(i, j) == oppCol |
| 130 | ) { |
| 131 | const oppPiece = this.getPiece(i, j); |
| 132 | if (oppPiece == V.IMMOBILIZER) return [i, j]; |
| 133 | // Only immobilizers are immobilized by chameleons: |
| 134 | if (oppPiece == V.BISHOP && piece == V.IMMOBILIZER) return [i, j]; |
| 135 | } |
| 136 | } |
| 137 | return null; |
| 138 | } |
| 139 | |
| 140 | getPotentialMovesFrom([x, y]) { |
| 141 | // Pre-check: is thing on this square immobilized? |
| 142 | const imSq = this.isImmobilized([x, y]); |
| 143 | const piece = this.getPiece(x, y); |
| 144 | if (!!imSq && piece != V.KING) { |
| 145 | // Only option is suicide, if I'm not a king: |
| 146 | return [ |
| 147 | new Move({ |
| 148 | start: { x: x, y: y }, |
| 149 | end: { x: imSq[0], y: imSq[1] }, |
| 150 | appear: [], |
| 151 | vanish: [ |
| 152 | new PiPo({ |
| 153 | x: x, |
| 154 | y: y, |
| 155 | c: this.getColor(x, y), |
| 156 | p: this.getPiece(x, y) |
| 157 | }) |
| 158 | ] |
| 159 | }) |
| 160 | ]; |
| 161 | } |
| 162 | let moves = undefined; |
| 163 | switch (piece) { |
| 164 | case V.IMMOBILIZER: |
| 165 | moves = this.getPotentialImmobilizerMoves([x, y]); |
| 166 | break; |
| 167 | case V.GUARD: |
| 168 | moves = this.getPotentialGuardMoves([x, y]); |
| 169 | break; |
| 170 | case V.MAGE: |
| 171 | moves = this.getPotentialMageMoves([x, y]); |
| 172 | break; |
| 173 | default: |
| 174 | moves = super.getPotentialMovesFrom([x, y]); |
| 175 | } |
| 176 | const pX = (this.turn == 'w' ? 10 : 0); |
| 177 | if (this.board[pX][3] == V.EMPTY && this.board[pX][4] == V.EMPTY) |
| 178 | return moves; |
| 179 | // Filter out moves resulting in self palace occupation: |
| 180 | // NOTE: cannot invade own palace but still check the king there. |
| 181 | const pY = (this.board[pX][3] != V.EMPTY ? 4 : 3); |
| 182 | return moves.filter(m => m.end.x != pX || m.end.y != pY); |
| 183 | } |
| 184 | |
| 185 | getSlideNJumpMoves([x, y], steps, oneStep, mageInitSquare) { |
| 186 | const piece = !mageInitSquare ? this.getPiece(x, y) : V.MAGE; |
| 187 | const initSquare = mageInitSquare || [x, y]; |
| 188 | let moves = []; |
| 189 | outerLoop: for (let step of steps) { |
| 190 | let i = x + step[0]; |
| 191 | let j = y + step[1]; |
| 192 | if (piece == V.KING) j = j % V.size.y; |
| 193 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { |
| 194 | moves.push(this.getBasicMove(initSquare, [i, j])); |
| 195 | if (!!oneStep) continue outerLoop; |
| 196 | i += step[0]; |
| 197 | j += step[1]; |
| 198 | } |
| 199 | // Only king, guard and mage (+ chameleon) can take on occupied square: |
| 200 | if ( |
| 201 | V.OnBoard(i, j) && |
| 202 | [V.KING, V.GUARD, V.MAGE].includes(piece) && |
| 203 | this.canTake(initSquare, [i, j]) |
| 204 | ) { |
| 205 | moves.push(this.getBasicMove(initSquare, [i, j])); |
| 206 | } |
| 207 | } |
| 208 | return moves; |
| 209 | } |
| 210 | |
| 211 | // Modify capturing moves among listed pawn moves |
| 212 | addPawnCaptures(moves, byChameleon) { |
| 213 | const steps = V.steps[V.ROOK]; |
| 214 | const color = this.turn; |
| 215 | const oppCol = V.GetOppCol(color); |
| 216 | moves.forEach(m => { |
| 217 | if (!!byChameleon && m.start.x != m.end.x && m.start.y != m.end.y) |
| 218 | // Chameleon not moving as pawn |
| 219 | return; |
| 220 | // Try capturing in every direction |
| 221 | for (let step of steps) { |
| 222 | const sq2 = [m.end.x + 2 * step[0], m.end.y + 2 * step[1]]; |
| 223 | if ( |
| 224 | V.OnBoard(sq2[0], sq2[1]) && |
| 225 | this.board[sq2[0]][sq2[1]] != V.EMPTY && |
| 226 | this.getColor(sq2[0], sq2[1]) == color |
| 227 | ) { |
| 228 | // Potential capture |
| 229 | const sq1 = [m.end.x + step[0], m.end.y + step[1]]; |
| 230 | if ( |
| 231 | this.board[sq1[0]][sq1[1]] != V.EMPTY && |
| 232 | this.getColor(sq1[0], sq1[1]) == oppCol |
| 233 | ) { |
| 234 | const piece1 = this.getPiece(sq1[0], sq1[1]); |
| 235 | if (!byChameleon || piece1 == V.PAWN) { |
| 236 | m.vanish.push( |
| 237 | new PiPo({ |
| 238 | x: sq1[0], |
| 239 | y: sq1[1], |
| 240 | c: oppCol, |
| 241 | p: piece1 |
| 242 | }) |
| 243 | ); |
| 244 | } |
| 245 | } |
| 246 | } |
| 247 | } |
| 248 | }); |
| 249 | } |
| 250 | |
| 251 | // "Pincer" |
| 252 | getPotentialPawnMoves([x, y]) { |
| 253 | let moves = super.getPotentialRookMoves([x, y]); |
| 254 | this.addPawnCaptures(moves); |
| 255 | return moves; |
| 256 | } |
| 257 | |
| 258 | addRookCaptures(moves, byChameleon) { |
| 259 | const color = this.turn; |
| 260 | const oppCol = V.GetOppCol(color); |
| 261 | const kp = this.kingPos[color]; |
| 262 | moves.forEach(m => { |
| 263 | // Check piece-king rectangle (if any) corners for enemy pieces |
| 264 | if (m.end.x == kp[0] || m.end.y == kp[1]) return; //"flat rectangle" |
| 265 | const corner1 = [m.end.x, kp[1]]; |
| 266 | const corner2 = [kp[0], m.end.y]; |
| 267 | for (let [i, j] of [corner1, corner2]) { |
| 268 | if (this.board[i][j] != V.EMPTY && this.getColor(i, j) == oppCol) { |
| 269 | const piece = this.getPiece(i, j); |
| 270 | if (!byChameleon || piece == V.ROOK) { |
| 271 | m.vanish.push( |
| 272 | new PiPo({ |
| 273 | x: i, |
| 274 | y: j, |
| 275 | p: piece, |
| 276 | c: oppCol |
| 277 | }) |
| 278 | ); |
| 279 | } |
| 280 | } |
| 281 | } |
| 282 | }); |
| 283 | } |
| 284 | |
| 285 | // Coordinator |
| 286 | getPotentialRookMoves(sq) { |
| 287 | let moves = super.getPotentialQueenMoves(sq); |
| 288 | this.addRookCaptures(moves); |
| 289 | return moves; |
| 290 | } |
| 291 | |
| 292 | getKnightCaptures(startSquare, byChameleon) { |
| 293 | // Look in every direction for captures |
| 294 | const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]); |
| 295 | const color = this.turn; |
| 296 | const oppCol = V.GetOppCol(color); |
| 297 | let moves = []; |
| 298 | const [x, y] = [startSquare[0], startSquare[1]]; |
| 299 | const piece = this.getPiece(x, y); //might be a chameleon! |
| 300 | outerLoop: for (let step of steps) { |
| 301 | let [i, j] = [x + step[0], y + step[1]]; |
| 302 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { |
| 303 | i += step[0]; |
| 304 | j += step[1]; |
| 305 | } |
| 306 | if ( |
| 307 | !V.OnBoard(i, j) || |
| 308 | this.getColor(i, j) == color || |
| 309 | (!!byChameleon && this.getPiece(i, j) != V.KNIGHT) |
| 310 | ) { |
| 311 | continue; |
| 312 | } |
| 313 | // last(thing), cur(thing) : stop if "cur" is our color, |
| 314 | // or beyond board limits, or if "last" isn't empty and cur neither. |
| 315 | // Otherwise, if cur is empty then add move until cur square; |
| 316 | // if cur is occupied then stop if !!byChameleon and the square not |
| 317 | // occupied by a leaper. |
| 318 | let last = [i, j]; |
| 319 | let cur = [i + step[0], j + step[1]]; |
| 320 | let vanished = [new PiPo({ x: x, y: y, c: color, p: piece })]; |
| 321 | while (V.OnBoard(cur[0], cur[1])) { |
| 322 | if (this.board[last[0]][last[1]] != V.EMPTY) { |
| 323 | const oppPiece = this.getPiece(last[0], last[1]); |
| 324 | if (!!byChameleon && oppPiece != V.KNIGHT) continue outerLoop; |
| 325 | // Something to eat: |
| 326 | vanished.push( |
| 327 | new PiPo({ x: last[0], y: last[1], c: oppCol, p: oppPiece }) |
| 328 | ); |
| 329 | } |
| 330 | if (this.board[cur[0]][cur[1]] != V.EMPTY) { |
| 331 | if ( |
| 332 | this.getColor(cur[0], cur[1]) == color || |
| 333 | this.board[last[0]][last[1]] != V.EMPTY |
| 334 | ) { |
| 335 | //TODO: redundant test |
| 336 | continue outerLoop; |
| 337 | } |
| 338 | } else { |
| 339 | moves.push( |
| 340 | new Move({ |
| 341 | appear: [new PiPo({ x: cur[0], y: cur[1], c: color, p: piece })], |
| 342 | vanish: JSON.parse(JSON.stringify(vanished)), //TODO: required? |
| 343 | start: { x: x, y: y }, |
| 344 | end: { x: cur[0], y: cur[1] } |
| 345 | }) |
| 346 | ); |
| 347 | } |
| 348 | last = [last[0] + step[0], last[1] + step[1]]; |
| 349 | cur = [cur[0] + step[0], cur[1] + step[1]]; |
| 350 | } |
| 351 | } |
| 352 | return moves; |
| 353 | } |
| 354 | |
| 355 | // Long-leaper |
| 356 | getPotentialKnightMoves(sq) { |
| 357 | return super.getPotentialQueenMoves(sq).concat(this.getKnightCaptures(sq)); |
| 358 | } |
| 359 | |
| 360 | // Chameleon |
| 361 | getPotentialBishopMoves([x, y]) { |
| 362 | let moves = super |
| 363 | .getPotentialQueenMoves([x, y]) |
| 364 | .concat(this.getKnightCaptures([x, y], "asChameleon")) |
| 365 | // No "king capture" because king cannot remain under check |
| 366 | this.addPawnCaptures(moves, "asChameleon"); |
| 367 | this.addRookCaptures(moves, "asChameleon"); |
| 368 | this.addQueenCaptures(moves, "asChameleon"); |
| 369 | // Manually add Guard and Mage captures (since cannot move like a Mage) |
| 370 | V.steps[V.ROOK].concat(V.steps[V.BISHOP]).forEach(step => { |
| 371 | const [i, j] = [x + step[0], y + step[1]]; |
| 372 | if ( |
| 373 | V.OnBoard(i, j) && |
| 374 | this.board[i][j] != V.EMPTY && |
| 375 | this.canTake([x, y], [i, j]) && |
| 376 | [V.GUARD, V.MAGE].includes(this.getPiece(i, j)) |
| 377 | ) { |
| 378 | moves.push(this.getBasicMove([x, y], [i, j])); |
| 379 | } |
| 380 | }); |
| 381 | // Post-processing: merge similar moves, concatenating vanish arrays |
| 382 | let mergedMoves = {}; |
| 383 | moves.forEach(m => { |
| 384 | const key = m.end.x + V.size.x * m.end.y; |
| 385 | if (!mergedMoves[key]) mergedMoves[key] = m; |
| 386 | else { |
| 387 | for (let i = 1; i < m.vanish.length; i++) |
| 388 | mergedMoves[key].vanish.push(m.vanish[i]); |
| 389 | } |
| 390 | }); |
| 391 | return Object.values(mergedMoves); |
| 392 | } |
| 393 | |
| 394 | addQueenCaptures(moves, byChameleon) { |
| 395 | if (moves.length == 0) return; |
| 396 | const [x, y] = [moves[0].start.x, moves[0].start.y]; |
| 397 | const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]); |
| 398 | let capturingDirections = []; |
| 399 | const color = this.turn; |
| 400 | const oppCol = V.GetOppCol(color); |
| 401 | adjacentSteps.forEach(step => { |
| 402 | const [i, j] = [x + step[0], y + step[1]]; |
| 403 | if ( |
| 404 | V.OnBoard(i, j) && |
| 405 | this.board[i][j] != V.EMPTY && |
| 406 | this.getColor(i, j) == oppCol && |
| 407 | (!byChameleon || this.getPiece(i, j) == V.QUEEN) |
| 408 | ) { |
| 409 | capturingDirections.push(step); |
| 410 | } |
| 411 | }); |
| 412 | moves.forEach(m => { |
| 413 | const step = [ |
| 414 | m.end.x != x ? (m.end.x - x) / Math.abs(m.end.x - x) : 0, |
| 415 | m.end.y != y ? (m.end.y - y) / Math.abs(m.end.y - y) : 0 |
| 416 | ]; |
| 417 | // TODO: this test should be done only once per direction |
| 418 | if ( |
| 419 | capturingDirections.some(dir => { |
| 420 | return dir[0] == -step[0] && dir[1] == -step[1]; |
| 421 | }) |
| 422 | ) { |
| 423 | const [i, j] = [x - step[0], y - step[1]]; |
| 424 | m.vanish.push( |
| 425 | new PiPo({ |
| 426 | x: i, |
| 427 | y: j, |
| 428 | p: this.getPiece(i, j), |
| 429 | c: oppCol |
| 430 | }) |
| 431 | ); |
| 432 | } |
| 433 | }); |
| 434 | } |
| 435 | |
| 436 | // Withdrawer |
| 437 | getPotentialQueenMoves(sq) { |
| 438 | let moves = super.getPotentialQueenMoves(sq); |
| 439 | this.addQueenCaptures(moves); |
| 440 | return moves; |
| 441 | } |
| 442 | |
| 443 | getPotentialImmobilizerMoves(sq) { |
| 444 | // Immobilizer doesn't capture |
| 445 | return super.getPotentialQueenMoves(sq); |
| 446 | } |
| 447 | |
| 448 | getPotentialKingMoves(sq) { |
| 449 | return this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep"); |
| 450 | } |
| 451 | |
| 452 | getPotentialGuardMoves(sq) { |
| 453 | return ( |
| 454 | this.getSlideNJumpMoves( |
| 455 | sq, |
| 456 | V.steps[V.ROOK].concat(V.steps[V.BISHOP]), |
| 457 | "oneStep", |
| 458 | null |
| 459 | ) |
| 460 | ); |
| 461 | } |
| 462 | |
| 463 | getNextMageSteps(step) { |
| 464 | if (step[0] == -1) { |
| 465 | if (step[1] == -1) return [[-1, 0], [0, -1]]; |
| 466 | return [[-1, 0], [0, 1]]; |
| 467 | } |
| 468 | if (step[1] == -1) return [[1, 0], [0, -1]]; |
| 469 | return [[1, 0], [0, 1]]; |
| 470 | } |
| 471 | |
| 472 | getPotentialMageMoves([x, y]) { |
| 473 | const oppCol = V.GetOppCol(this.turn); |
| 474 | let moves = []; |
| 475 | for (let step of V.steps[V.BISHOP]) { |
| 476 | let [i, j] = [x + step[0], y + step[1]]; |
| 477 | if (!V.OnBoard(i, j)) continue; |
| 478 | if (this.board[i][j] != V.EMPTY) { |
| 479 | if (this.getColor(i, j) == oppCol) |
| 480 | // Capture |
| 481 | moves.push(this.getBasicMove([x, y], [i, j])); |
| 482 | } |
| 483 | else { |
| 484 | moves.push(this.getBasicMove([x, y], [i, j])); |
| 485 | // Continue orthogonally: |
| 486 | const stepO = this.getNextMageSteps(step); |
| 487 | Array.prototype.push.apply( |
| 488 | moves, |
| 489 | this.getSlideNJumpMoves([i, j], stepO, null, [x, y]) |
| 490 | ); |
| 491 | } |
| 492 | } |
| 493 | return moves; |
| 494 | } |
| 495 | |
| 496 | isAttacked(sq, color) { |
| 497 | return ( |
| 498 | super.isAttacked(sq, color) || |
| 499 | this.isAttackedByGuard(sq, color) || |
| 500 | this.isAttackedByMage(sq, color) |
| 501 | ); |
| 502 | } |
| 503 | |
| 504 | isAttackedByPawn([x, y], color) { |
| 505 | // Square (x,y) must be surroundable by two enemy pieces, |
| 506 | // and one of them at least should be a pawn (moving). |
| 507 | const dirs = [ |
| 508 | [1, 0], |
| 509 | [0, 1] |
| 510 | ]; |
| 511 | const steps = V.steps[V.ROOK]; |
| 512 | for (let dir of dirs) { |
| 513 | const [i1, j1] = [x - dir[0], y - dir[1]]; //"before" |
| 514 | const [i2, j2] = [x + dir[0], y + dir[1]]; //"after" |
| 515 | if (V.OnBoard(i1, j1) && V.OnBoard(i2, j2)) { |
| 516 | if ( |
| 517 | ( |
| 518 | this.board[i1][j1] != V.EMPTY && |
| 519 | this.getColor(i1, j1) == color && |
| 520 | this.board[i2][j2] == V.EMPTY |
| 521 | ) |
| 522 | || |
| 523 | ( |
| 524 | this.board[i2][j2] != V.EMPTY && |
| 525 | this.getColor(i2, j2) == color && |
| 526 | this.board[i1][j1] == V.EMPTY |
| 527 | ) |
| 528 | ) { |
| 529 | // Search a movable enemy pawn landing on the empty square |
| 530 | for (let step of steps) { |
| 531 | let [ii, jj] = this.board[i1][j1] == V.EMPTY ? [i1, j1] : [i2, j2]; |
| 532 | let [i3, j3] = [ii + step[0], jj + step[1]]; |
| 533 | while (V.OnBoard(i3, j3) && this.board[i3][j3] == V.EMPTY) { |
| 534 | i3 += step[0]; |
| 535 | j3 += step[1]; |
| 536 | } |
| 537 | if ( |
| 538 | V.OnBoard(i3, j3) && |
| 539 | this.getColor(i3, j3) == color && |
| 540 | this.getPiece(i3, j3) == V.PAWN && |
| 541 | !this.isImmobilized([i3, j3]) |
| 542 | ) { |
| 543 | return true; |
| 544 | } |
| 545 | } |
| 546 | } |
| 547 | } |
| 548 | } |
| 549 | return false; |
| 550 | } |
| 551 | |
| 552 | isAttackedByRook([x, y], color) { |
| 553 | // King must be on same column or row, |
| 554 | // and a rook should be able to reach a capturing square |
| 555 | const sameRow = x == this.kingPos[color][0]; |
| 556 | const sameColumn = y == this.kingPos[color][1]; |
| 557 | if (sameRow || sameColumn) { |
| 558 | // Look for the enemy rook (maximum 1) |
| 559 | for (let i = 0; i < V.size.x; i++) { |
| 560 | for (let j = 0; j < V.size.y; j++) { |
| 561 | if ( |
| 562 | this.board[i][j] != V.EMPTY && |
| 563 | this.getColor(i, j) == color && |
| 564 | this.getPiece(i, j) == V.ROOK |
| 565 | ) { |
| 566 | if (this.isImmobilized([i, j])) |
| 567 | // Because only one rook: |
| 568 | return false; |
| 569 | // Can it reach a capturing square? Easy but quite suboptimal way |
| 570 | // (TODO: generate all moves (turn is OK)) |
| 571 | const moves = this.getPotentialMovesFrom([i, j]); |
| 572 | for (let move of moves) { |
| 573 | if ( |
| 574 | (sameRow && move.end.y == y) || |
| 575 | (sameColumn && move.end.x == x) |
| 576 | ) { |
| 577 | return true; |
| 578 | } |
| 579 | } |
| 580 | } |
| 581 | } |
| 582 | } |
| 583 | } |
| 584 | return false; |
| 585 | } |
| 586 | |
| 587 | isAttackedByKnight([x, y], color) { |
| 588 | // Square (x,y) must be on same line as a knight, |
| 589 | // and there must be empty square(s) behind. |
| 590 | const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]); |
| 591 | outerLoop: for (let step of steps) { |
| 592 | const [i0, j0] = [x + step[0], y + step[1]]; |
| 593 | if (V.OnBoard(i0, j0) && this.board[i0][j0] == V.EMPTY) { |
| 594 | // Try in opposite direction: |
| 595 | let [i, j] = [x - step[0], y - step[1]]; |
| 596 | while (V.OnBoard(i, j)) { |
| 597 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { |
| 598 | i -= step[0]; |
| 599 | j -= step[1]; |
| 600 | } |
| 601 | if (V.OnBoard(i, j)) { |
| 602 | if (this.getColor(i, j) == color) { |
| 603 | if ( |
| 604 | this.getPiece(i, j) == V.KNIGHT && |
| 605 | !this.isImmobilized([i, j]) |
| 606 | ) { |
| 607 | return true; |
| 608 | } |
| 609 | continue outerLoop; |
| 610 | } |
| 611 | // [else] Our color, |
| 612 | // could be captured *if there was an empty space* |
| 613 | if (this.board[i + step[0]][j + step[1]] != V.EMPTY) |
| 614 | continue outerLoop; |
| 615 | i -= step[0]; |
| 616 | j -= step[1]; |
| 617 | } |
| 618 | } |
| 619 | } |
| 620 | } |
| 621 | return false; |
| 622 | } |
| 623 | |
| 624 | isAttackedByBishop([x, y], color) { |
| 625 | // We cheat a little here: since this function is used exclusively for |
| 626 | // the king, it's enough to check the immediate surrounding of the square. |
| 627 | const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]); |
| 628 | for (let step of adjacentSteps) { |
| 629 | const [i, j] = [x + step[0], y + step[1]]; |
| 630 | if ( |
| 631 | V.OnBoard(i, j) && |
| 632 | this.board[i][j] != V.EMPTY && |
| 633 | this.getColor(i, j) == color && |
| 634 | this.getPiece(i, j) == V.BISHOP && |
| 635 | !this.isImmobilized([i, j]) |
| 636 | ) { |
| 637 | return true; |
| 638 | } |
| 639 | } |
| 640 | return false; |
| 641 | } |
| 642 | |
| 643 | isAttackedByQueen([x, y], color) { |
| 644 | // Square (x,y) must be adjacent to a queen, and the queen must have |
| 645 | // some free space in the opposite direction from (x,y) |
| 646 | const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]); |
| 647 | for (let step of adjacentSteps) { |
| 648 | const sq2 = [x + 2 * step[0], y + 2 * step[1]]; |
| 649 | if (V.OnBoard(sq2[0], sq2[1]) && this.board[sq2[0]][sq2[1]] == V.EMPTY) { |
| 650 | const sq1 = [x + step[0], y + step[1]]; |
| 651 | if ( |
| 652 | this.board[sq1[0]][sq1[1]] != V.EMPTY && |
| 653 | this.getColor(sq1[0], sq1[1]) == color && |
| 654 | this.getPiece(sq1[0], sq1[1]) == V.QUEEN && |
| 655 | !this.isImmobilized(sq1) |
| 656 | ) { |
| 657 | return true; |
| 658 | } |
| 659 | } |
| 660 | } |
| 661 | return false; |
| 662 | } |
| 663 | |
| 664 | isAttackedByKing([x, y], color) { |
| 665 | for (let step of V.steps[V.KNIGHT]) { |
| 666 | let rx = x + step[0], |
| 667 | // Circular board for king-knight: |
| 668 | ry = (y + step[1]) % V.size.y; |
| 669 | if ( |
| 670 | V.OnBoard(rx, ry) && |
| 671 | this.getPiece(rx, ry) === V.KING && |
| 672 | this.getColor(rx, ry) == color && |
| 673 | !this.isImmobilized([rx, ry]) |
| 674 | ) { |
| 675 | return true; |
| 676 | } |
| 677 | } |
| 678 | return false; |
| 679 | } |
| 680 | |
| 681 | isAttackedByGuard(sq, color) { |
| 682 | return ( |
| 683 | super.isAttackedBySlideNJump( |
| 684 | sq, |
| 685 | color, |
| 686 | V.GUARD, |
| 687 | V.steps[V.ROOK].concat(V.steps[V.BISHOP]), |
| 688 | "oneStep" |
| 689 | ) |
| 690 | ); |
| 691 | } |
| 692 | |
| 693 | getNextMageCheck(step) { |
| 694 | if (step[0] == 0) { |
| 695 | if (step[1] == 1) return [[1, 1], [-1, 1]]; |
| 696 | return [[-1, -1], [1, -1]]; |
| 697 | } |
| 698 | if (step[0] == -1) return [[-1, -1], [-1, 1]]; |
| 699 | return [[1, 1], [1, -1]]; |
| 700 | } |
| 701 | |
| 702 | isAttackedByMage([x, y], color) { |
| 703 | for (let step of V.steps[V.BISHOP]) { |
| 704 | const [i, j] = [x + step[0], y + step[1]]; |
| 705 | if ( |
| 706 | V.OnBoard(i, j) && |
| 707 | this.board[i][j] != V.EMPTY && |
| 708 | this.getColor(i, j) == color && |
| 709 | this.getPiece(i, j) == V.MAGE |
| 710 | ) { |
| 711 | return true; |
| 712 | } |
| 713 | } |
| 714 | for (let step of V.steps[V.ROOK]) { |
| 715 | let [i, j] = [x + step[0], y + step[1]]; |
| 716 | const stepM = this.getNextMageCheck(step); |
| 717 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { |
| 718 | for (let s of stepM) { |
| 719 | const [ii, jj] = [i + s[0], j + s[1]]; |
| 720 | if ( |
| 721 | V.OnBoard(ii, jj) && |
| 722 | this.board[ii][jj] != V.EMPTY && |
| 723 | this.getColor(ii, jj) == color && |
| 724 | this.getPiece(ii, jj) == V.MAGE |
| 725 | ) { |
| 726 | return true; |
| 727 | } |
| 728 | } |
| 729 | i += step[0]; |
| 730 | j += step[1]; |
| 731 | } |
| 732 | } |
| 733 | return false; |
| 734 | } |
| 735 | |
| 736 | getCurrentScore() { |
| 737 | const color = this.turn; |
| 738 | const getScoreLost = () => { |
| 739 | // Result if I lose: |
| 740 | return color == "w" ? "0-1" : "1-0"; |
| 741 | }; |
| 742 | if (!this.atLeastOneMove()) { |
| 743 | // No valid move: I lose or draw |
| 744 | if (this.underCheck(color)) return getScoreLost(); |
| 745 | return "1/2"; |
| 746 | } |
| 747 | // I lose also if no pieces left (except king) |
| 748 | let piecesLeft = 0; |
| 749 | outerLoop: for (let i=0; i<V.size.x; i++) { |
| 750 | for (let j=0; j<V.size.y; j++) { |
| 751 | if ( |
| 752 | this.board[i][j] != V.EMPTY && |
| 753 | this.getColor(i, j) == color && |
| 754 | this.getPiece(i,j) != V.KING |
| 755 | ) { |
| 756 | piecesLeft++; |
| 757 | } |
| 758 | } |
| 759 | } |
| 760 | if (piecesLeft == 0) return getScoreLost(); |
| 761 | // Check if my palace is invaded: |
| 762 | const pX = (color == 'w' ? 10 : 0); |
| 763 | const oppCol = V.GetOppCol(color); |
| 764 | if ( |
| 765 | this.board[pX][3] != V.EMPTY && |
| 766 | this.getColor(pX, 3) == oppCol && |
| 767 | this.board[pX][4] != V.EMPTY && |
| 768 | this.getColor(pX, 4) == oppCol |
| 769 | ) { |
| 770 | return getScoreLost(); |
| 771 | } |
| 772 | return "*"; |
| 773 | } |
| 774 | |
| 775 | static GenRandInitFen() { |
| 776 | // Always deterministic: |
| 777 | return ( |
| 778 | "xxx2xxx/1g1qk1g1/1bnmrnb1/dppppppd/8/8/8/" + |
| 779 | "DPPPPPPD/1BNMRNB1/1G1QK1G1/xxx2xxx w 0" |
| 780 | ); |
| 781 | } |
| 782 | |
| 783 | static get VALUES() { |
| 784 | return { |
| 785 | p: 1, |
| 786 | r: 2, |
| 787 | n: 5, |
| 788 | b: 4, |
| 789 | q: 2, |
| 790 | m: 5, |
| 791 | g: 7, |
| 792 | d: 4, |
| 793 | k: 1000 |
| 794 | }; |
| 795 | } |
| 796 | |
| 797 | static get SEARCH_DEPTH() { |
| 798 | return 2; |
| 799 | } |
| 800 | |
| 801 | evalPosition() { |
| 802 | let evaluation = 0; |
| 803 | for (let i = 0; i < V.size.x; i++) { |
| 804 | for (let j = 0; j < V.size.y; j++) { |
| 805 | if (![V.EMPTY,V.NOTHING].includes(this.board[i][j])) { |
| 806 | const sign = this.getColor(i, j) == "w" ? 1 : -1; |
| 807 | evaluation += sign * V.VALUES[this.getPiece(i, j)]; |
| 808 | } |
| 809 | } |
| 810 | } |
| 811 | return evaluation; |
| 812 | } |
| 813 | |
| 814 | getNotation(move) { |
| 815 | const initialSquare = V.CoordsToSquare(move.start); |
| 816 | const finalSquare = V.CoordsToSquare(move.end); |
| 817 | if (move.appear.length == 0) |
| 818 | // Suicide 'S' |
| 819 | return initialSquare + "S"; |
| 820 | let notation = undefined; |
| 821 | if (move.appear[0].p == V.PAWN) { |
| 822 | // Pawn: generally ambiguous short notation, so we use full description |
| 823 | notation = "P" + initialSquare + finalSquare; |
| 824 | } else if (move.appear[0].p == V.KING) |
| 825 | notation = "K" + (move.vanish.length > 1 ? "x" : "") + finalSquare; |
| 826 | else notation = move.appear[0].p.toUpperCase() + finalSquare; |
| 827 | // Add a capture mark (not describing what is captured...): |
| 828 | if (move.vanish.length > 1 && move.appear[0].p != V.KING) notation += "X"; |
| 829 | return notation; |
| 830 | } |
| 831 | |
| 832 | }; |