client/src/variants/Wildebeest.js

   1 import { ChessRules } 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           var 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   // TODO: wildebeest castle
 182
 183   getPotentialCamelMoves(sq) {
 184     return this.getSlideNJumpMoves(sq, V.steps[V.CAMEL], "oneStep");
 185   }
 186
 187   getPotentialWildebeestMoves(sq) {
 188     return this.getSlideNJumpMoves(
 189       sq,
 190       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 191       "oneStep"
 192     );
 193   }
 194
 195   isAttacked(sq, color) {
 196     return (
 197       super.isAttacked(sq, color) ||
 198       this.isAttackedByCamel(sq, color) ||
 199       this.isAttackedByWildebeest(sq, color)
 200     );
 201   }
 202
 203   isAttackedByCamel(sq, color) {
 204     return this.isAttackedBySlideNJump(
 205       sq,
 206       color,
 207       V.CAMEL,
 208       V.steps[V.CAMEL],
 209       "oneStep"
 210     );
 211   }
 212
 213   isAttackedByWildebeest(sq, color) {
 214     return this.isAttackedBySlideNJump(
 215       sq,
 216       color,
 217       V.WILDEBEEST,
 218       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 219       "oneStep"
 220     );
 221   }
 222
 223   getCurrentScore() {
 224     if (this.atLeastOneMove()) return "*";
 225     // No valid move: game is lost (stalemate is a win)
 226     return this.turn == "w" ? "0-1" : "1-0";
 227   }
 228
 229   static get VALUES() {
 230     return Object.assign(
 231       { c: 3, w: 7 }, //experimental
 232       ChessRules.VALUES
 233     );
 234   }
 235
 236   static get SEARCH_DEPTH() {
 237     return 2;
 238   }
 239
 240   static GenRandInitFen(randomness) {
 241     if (!randomness) randomness = 2;
 242     if (randomness == 0) {
 243       return (
 244         "rnccwkqbbnr/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/RNBBQKWCCNR " +
 245         "w 0 akak -"
 246       );
 247     }
 248
 249     let pieces = { w: new Array(11), b: new Array(11) };
 250     let flags = "";
 251     for (let c of ["w", "b"]) {
 252       if (c == 'b' && randomness == 1) {
 253         pieces['b'] = pieces['w'];
 254         flags += flags;
 255         break;
 256       }
 257
 258       let positions = ArrayFun.range(11);
 259
 260       // Get random squares for bishops + camels (different colors)
 261       let randIndexes = sample(ArrayFun.range(6), 2).map(i => {
 262         return 2 * i;
 263       });
 264       let bishop1Pos = positions[randIndexes[0]];
 265       let camel1Pos = positions[randIndexes[1]];
 266       // The second bishop (camel) must be on a square of different color
 267       let randIndexes_tmp = sample(ArrayFun.range(5), 2).map(i => {
 268         return 2 * i + 1;
 269       });
 270       let bishop2Pos = positions[randIndexes_tmp[0]];
 271       let camel2Pos = positions[randIndexes_tmp[1]];
 272       for (let idx of randIndexes.concat(randIndexes_tmp).sort((a, b) => {
 273         return b - a;
 274       })) {
 275         // Largest indices first
 276         positions.splice(idx, 1);
 277       }
 278
 279       let randIndex = randInt(7);
 280       let knight1Pos = positions[randIndex];
 281       positions.splice(randIndex, 1);
 282       randIndex = randInt(6);
 283       let knight2Pos = positions[randIndex];
 284       positions.splice(randIndex, 1);
 285
 286       randIndex = randInt(5);
 287       let queenPos = positions[randIndex];
 288       positions.splice(randIndex, 1);
 289
 290       // Random square for wildebeest
 291       randIndex = randInt(4);
 292       let wildebeestPos = positions[randIndex];
 293       positions.splice(randIndex, 1);
 294
 295       let rook1Pos = positions[0];
 296       let kingPos = positions[1];
 297       let rook2Pos = positions[2];
 298
 299       pieces[c][rook1Pos] = "r";
 300       pieces[c][knight1Pos] = "n";
 301       pieces[c][bishop1Pos] = "b";
 302       pieces[c][queenPos] = "q";
 303       pieces[c][camel1Pos] = "c";
 304       pieces[c][camel2Pos] = "c";
 305       pieces[c][wildebeestPos] = "w";
 306       pieces[c][kingPos] = "k";
 307       pieces[c][bishop2Pos] = "b";
 308       pieces[c][knight2Pos] = "n";
 309       pieces[c][rook2Pos] = "r";
 310       flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos);
 311     }
 312     return (
 313       pieces["b"].join("") +
 314       "/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/" +
 315       pieces["w"].join("").toUpperCase() +
 316       " w 0 " + flags + " -"
 317     );
 318   }
 319
 320 };