client/src/variants/Wildebeest.js

   1 import { ChessRules, Move, PiPo } from "@/base_rules";
   2 import { ArrayFun } from "@/utils/array";
   3 import { sample, randInt } from "@/utils/alea";
   4
   5 export class WildebeestRules extends ChessRules {
   6
   7   static get size() {
   8     return { x: 10, y: 11 };
   9   }
  10
  11   static get CAMEL() {
  12     return "c";
  13   }
  14   static get WILDEBEEST() {
  15     return "w";
  16   }
  17
  18   static get PIECES() {
  19     return ChessRules.PIECES.concat([V.CAMEL, V.WILDEBEEST]);
  20   }
  21
  22   static get steps() {
  23     return Object.assign(
  24       {},
  25       ChessRules.steps,
  26       // Add camel moves:
  27       {
  28         c: [
  29           [-3, -1],
  30           [-3, 1],
  31           [-1, -3],
  32           [-1, 3],
  33           [1, -3],
  34           [1, 3],
  35           [3, -1],
  36           [3, 1]
  37         ]
  38       }
  39     );
  40   }
  41
  42   static IsGoodEnpassant(enpassant) {
  43     if (enpassant != "-") return !!enpassant.match(/^([a-j][0-9]{1,2},?)+$/);
  44     return true;
  45   }
  46
  47   getPpath(b) {
  48     return ([V.CAMEL, V.WILDEBEEST].includes(b[1]) ? "Wildebeest/" : "") + b;
  49   }
  50
  51   // There may be 2 enPassant squares (if pawn jump 3 squares)
  52   getEnpassantFen() {
  53     const L = this.epSquares.length;
  54     if (!this.epSquares[L - 1]) return "-"; //no en-passant
  55     let res = "";
  56     this.epSquares[L - 1].forEach(sq => {
  57       res += V.CoordsToSquare(sq) + ",";
  58     });
  59     return res.slice(0, -1); //remove last comma
  60   }
  61
  62   // En-passant after 2-sq or 3-sq jumps
  63   getEpSquare(moveOrSquare) {
  64     if (!moveOrSquare) return undefined;
  65     if (typeof moveOrSquare === "string") {
  66       const square = moveOrSquare;
  67       if (square == "-") return undefined;
  68       let res = [];
  69       square.split(",").forEach(sq => {
  70         res.push(V.SquareToCoords(sq));
  71       });
  72       return res;
  73     }
  74     // Argument is a move:
  75     const move = moveOrSquare;
  76     const [sx, sy, ex] = [move.start.x, move.start.y, move.end.x];
  77     if (this.getPiece(sx, sy) == V.PAWN && Math.abs(sx - ex) >= 2) {
  78       const step = (ex - sx) / Math.abs(ex - sx);
  79       let res = [
  80         {
  81           x: sx + step,
  82           y: sy
  83         }
  84       ];
  85       if (sx + 2 * step != ex) {
  86         // 3-squares move
  87         res.push({
  88           x: sx + 2 * step,
  89           y: sy
  90         });
  91       }
  92       return res;
  93     }
  94     return undefined; //default
  95   }
  96
  97   getPotentialMovesFrom([x, y]) {
  98     switch (this.getPiece(x, y)) {
  99       case V.CAMEL:
 100         return this.getPotentialCamelMoves([x, y]);
 101       case V.WILDEBEEST:
 102         return this.getPotentialWildebeestMoves([x, y]);
 103       default:
 104         return super.getPotentialMovesFrom([x, y]);
 105     }
 106   }
 107
 108   // Pawns jump 2 or 3 squares, and promote to queen or wildebeest
 109   getPotentialPawnMoves([x, y]) {
 110     const color = this.turn;
 111     let moves = [];
 112     const [sizeX, sizeY] = [V.size.x, V.size.y];
 113     const shiftX = color == "w" ? -1 : 1;
 114     const startRanks = color == "w" ? [sizeX - 2, sizeX - 3] : [1, 2];
 115     const lastRank = color == "w" ? 0 : sizeX - 1;
 116     const finalPieces = x + shiftX == lastRank
 117       ? [V.WILDEBEEST, V.QUEEN]
 118       : [V.PAWN];
 119
 120     if (this.board[x + shiftX][y] == V.EMPTY) {
 121       // One square forward
 122       for (let piece of finalPieces)
 123         moves.push(
 124           this.getBasicMove([x, y], [x + shiftX, y], { c: color, p: piece })
 125         );
 126       if (startRanks.includes(x)) {
 127         if (this.board[x + 2 * shiftX][y] == V.EMPTY) {
 128           // Two squares jump
 129           moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
 130           if (x == startRanks[0] && this.board[x + 3 * shiftX][y] == V.EMPTY) {
 131             // Three squares jump
 132             moves.push(this.getBasicMove([x, y], [x + 3 * shiftX, y]));
 133           }
 134         }
 135       }
 136     }
 137     // Captures
 138     for (let shiftY of [-1, 1]) {
 139       if (
 140         y + shiftY >= 0 &&
 141         y + shiftY < sizeY &&
 142         this.board[x + shiftX][y + shiftY] != V.EMPTY &&
 143         this.canTake([x, y], [x + shiftX, y + shiftY])
 144       ) {
 145         for (let piece of finalPieces) {
 146           moves.push(
 147             this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
 148               c: color,
 149               p: piece
 150             })
 151           );
 152         }
 153       }
 154     }
 155
 156     // En passant
 157     const Lep = this.epSquares.length;
 158     const epSquare = this.epSquares[Lep - 1];
 159     if (!!epSquare) {
 160       for (let epsq of epSquare) {
 161         // TODO: some redundant checks
 162         if (epsq.x == x + shiftX && Math.abs(epsq.y - y) == 1) {
 163           let enpassantMove = this.getBasicMove([x, y], [epsq.x, epsq.y]);
 164           // WARNING: the captured pawn may be diagonally behind us,
 165           // if it's a 3-squares jump and we take on 1st passing square
 166           const px = this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX;
 167           enpassantMove.vanish.push({
 168             x: px,
 169             y: epsq.y,
 170             p: "p",
 171             c: this.getColor(px, epsq.y)
 172           });
 173           moves.push(enpassantMove);
 174         }
 175       }
 176     }
 177
 178     return moves;
 179   }
 180
 181   getPotentialCamelMoves(sq) {
 182     return this.getSlideNJumpMoves(sq, V.steps[V.CAMEL], "oneStep");
 183   }
 184
 185   getPotentialWildebeestMoves(sq) {
 186     return this.getSlideNJumpMoves(
 187       sq,
 188       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 189       "oneStep"
 190     );
 191   }
 192
 193   getPPpath(m) {
 194     if (
 195       m.appear.length == 2 && m.vanish.length == 2 &&
 196       Math.abs(m.end.y - m.start.y) == 1 &&
 197       this.board[m.end.x][m.end.y] == V.EMPTY
 198     ) {
 199       // Castle, king moved by one square only, not directly onto rook
 200       return "Wildebeest/castle";
 201     }
 202     return super.getPPpath(m);
 203   }
 204
 205   // Special Wildebeest castling rules:
 206   getCastleMoves([x, y]) {
 207     const c = this.getColor(x, y);
 208     const oppCol = V.GetOppCol(c);
 209     let moves = [];
 210     let i = 0;
 211     const castlingKing = this.board[x][y].charAt(1);
 212     castlingCheck: for (
 213       let castleSide = 0;
 214       castleSide < 2;
 215       castleSide++ //"large", then "small"
 216     ) {
 217       if (this.castleFlags[c][castleSide] >= V.size.y) continue;
 218       // Rook and king are on initial position
 219       const rookPos = this.castleFlags[c][castleSide];
 220       const range = (castleSide == 0 ? [rookPos, y] : [y, rookPos]);
 221
 222       // King and rook must be connected:
 223       for (let i = range[0] + 1; i <= range[1] - 1; i++) {
 224         if (this.board[x][i] != V.EMPTY) continue castlingCheck;
 225       }
 226       const step = 2 * castleSide - 1;
 227       // No attacks on the path of the king ?
 228       for (let i = range[0]; i <= range[1]; i++) {
 229         if (i != rookPos && this.isAttacked([x, i], oppCol))
 230           continue castlingCheck;
 231         if (
 232           i != y &&
 233           // Do not end in the corner, except if starting square is too near
 234           (i > 0 || y == 1) &&
 235           (i < V.size.y - 1 || y == V.size.y - 2)
 236         ) {
 237           // Found a possible castle move:
 238           moves.push(
 239             new Move({
 240               appear: [
 241                 new PiPo({
 242                   x: x,
 243                   y: i,
 244                   p: V.KING,
 245                   c: c
 246                 }),
 247                 new PiPo({
 248                   x: x,
 249                   y: i - step,
 250                   p: V.ROOK,
 251                   c: c
 252                 })
 253               ],
 254               vanish: [
 255                 new PiPo({ x: x, y: y, p: V.KING, c: c }),
 256                 new PiPo({ x: x, y: rookPos, p: V.ROOK, c: c })
 257               ]
 258             })
 259           );
 260         }
 261       }
 262     }
 263
 264     return moves;
 265   }
 266
 267   isAttacked(sq, color) {
 268     return (
 269       super.isAttacked(sq, color) ||
 270       this.isAttackedByCamel(sq, color) ||
 271       this.isAttackedByWildebeest(sq, color)
 272     );
 273   }
 274
 275   isAttackedByCamel(sq, color) {
 276     return this.isAttackedBySlideNJump(
 277       sq,
 278       color,
 279       V.CAMEL,
 280       V.steps[V.CAMEL],
 281       "oneStep"
 282     );
 283   }
 284
 285   isAttackedByWildebeest(sq, color) {
 286     return this.isAttackedBySlideNJump(
 287       sq,
 288       color,
 289       V.WILDEBEEST,
 290       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 291       "oneStep"
 292     );
 293   }
 294
 295   getCurrentScore() {
 296     if (this.atLeastOneMove()) return "*";
 297     // No valid move: game is lost (stalemate is a win)
 298     return this.turn == "w" ? "0-1" : "1-0";
 299   }
 300
 301   static get VALUES() {
 302     return Object.assign(
 303       { c: 3, w: 7 }, //experimental
 304       ChessRules.VALUES
 305     );
 306   }
 307
 308   static get SEARCH_DEPTH() {
 309     return 2;
 310   }
 311
 312   static GenRandInitFen(randomness) {
 313     if (randomness == 0) {
 314       return (
 315         "rnccwkqbbnr/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/RNBBQKWCCNR " +
 316         "w 0 akak -"
 317       );
 318     }
 319
 320     let pieces = { w: new Array(11), b: new Array(11) };
 321     let flags = "";
 322     for (let c of ["w", "b"]) {
 323       if (c == 'b' && randomness == 1) {
 324         pieces['b'] = pieces['w'];
 325         flags += flags;
 326         break;
 327       }
 328
 329       let positions = ArrayFun.range(11);
 330
 331       // Get random squares for bishops + camels (different colors)
 332       let randIndexes = sample(ArrayFun.range(6), 2).map(i => {
 333         return 2 * i;
 334       });
 335       let bishop1Pos = positions[randIndexes[0]];
 336       let camel1Pos = positions[randIndexes[1]];
 337       // The second bishop (camel) must be on a square of different color
 338       let randIndexes_tmp = sample(ArrayFun.range(5), 2).map(i => {
 339         return 2 * i + 1;
 340       });
 341       let bishop2Pos = positions[randIndexes_tmp[0]];
 342       let camel2Pos = positions[randIndexes_tmp[1]];
 343       for (let idx of randIndexes.concat(randIndexes_tmp).sort((a, b) => {
 344         return b - a;
 345       })) {
 346         // Largest indices first
 347         positions.splice(idx, 1);
 348       }
 349
 350       let randIndex = randInt(7);
 351       let knight1Pos = positions[randIndex];
 352       positions.splice(randIndex, 1);
 353       randIndex = randInt(6);
 354       let knight2Pos = positions[randIndex];
 355       positions.splice(randIndex, 1);
 356
 357       randIndex = randInt(5);
 358       let queenPos = positions[randIndex];
 359       positions.splice(randIndex, 1);
 360
 361       // Random square for wildebeest
 362       randIndex = randInt(4);
 363       let wildebeestPos = positions[randIndex];
 364       positions.splice(randIndex, 1);
 365
 366       let rook1Pos = positions[0];
 367       let kingPos = positions[1];
 368       let rook2Pos = positions[2];
 369
 370       pieces[c][rook1Pos] = "r";
 371       pieces[c][knight1Pos] = "n";
 372       pieces[c][bishop1Pos] = "b";
 373       pieces[c][queenPos] = "q";
 374       pieces[c][camel1Pos] = "c";
 375       pieces[c][camel2Pos] = "c";
 376       pieces[c][wildebeestPos] = "w";
 377       pieces[c][kingPos] = "k";
 378       pieces[c][bishop2Pos] = "b";
 379       pieces[c][knight2Pos] = "n";
 380       pieces[c][rook2Pos] = "r";
 381       flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos);
 382     }
 383     return (
 384       pieces["b"].join("") +
 385       "/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/" +
 386       pieces["w"].join("").toUpperCase() +
 387       " w 0 " + flags + " -"
 388     );
 389   }
 390
 391 };