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   static get size() {
   7     return { x: 10, y: 11 };
   8   }
   9
  10   static get CAMEL() {
  11     return "c";
  12   }
  13   static get WILDEBEEST() {
  14     return "w";
  15   }
  16
  17   static get PIECES() {
  18     return ChessRules.PIECES.concat([V.CAMEL, V.WILDEBEEST]);
  19   }
  20
  21   static get steps() {
  22     return Object.assign(
  23       {},
  24       ChessRules.steps,
  25       // Add camel moves:
  26       {
  27         c: [
  28           [-3, -1],
  29           [-3, 1],
  30           [-1, -3],
  31           [-1, 3],
  32           [1, -3],
  33           [1, 3],
  34           [3, -1],
  35           [3, 1]
  36         ]
  37       }
  38     );
  39   }
  40
  41   static IsGoodEnpassant(enpassant) {
  42     if (enpassant != "-") return !!enpassant.match(/^([a-j][0-9]{1,2},?)+$/);
  43     return true;
  44   }
  45
  46   getPpath(b) {
  47     return ([V.CAMEL, V.WILDEBEEST].includes(b[1]) ? "Wildebeest/" : "") + b;
  48   }
  49
  50   // There may be 2 enPassant squares (if pawn jump 3 squares)
  51   getEnpassantFen() {
  52     const L = this.epSquares.length;
  53     if (!this.epSquares[L - 1]) return "-"; //no en-passant
  54     let res = "";
  55     this.epSquares[L - 1].forEach(sq => {
  56       res += V.CoordsToSquare(sq) + ",";
  57     });
  58     return res.slice(0, -1); //remove last comma
  59   }
  60
  61   // En-passant after 2-sq or 3-sq jumps
  62   getEpSquare(moveOrSquare) {
  63     if (!moveOrSquare) return undefined;
  64     if (typeof moveOrSquare === "string") {
  65       const square = moveOrSquare;
  66       if (square == "-") return undefined;
  67       let res = [];
  68       square.split(",").forEach(sq => {
  69         res.push(V.SquareToCoords(sq));
  70       });
  71       return res;
  72     }
  73     // Argument is a move:
  74     const move = moveOrSquare;
  75     const [sx, sy, ex] = [move.start.x, move.start.y, move.end.x];
  76     if (this.getPiece(sx, sy) == V.PAWN && Math.abs(sx - ex) >= 2) {
  77       const step = (ex - sx) / Math.abs(ex - sx);
  78       let res = [
  79         {
  80           x: sx + step,
  81           y: sy
  82         }
  83       ];
  84       if (sx + 2 * step != ex) {
  85         //3-squares move
  86         res.push({
  87           x: sx + 2 * step,
  88           y: sy
  89         });
  90       }
  91       return res;
  92     }
  93     return undefined; //default
  94   }
  95
  96   getPotentialMovesFrom([x, y]) {
  97     switch (this.getPiece(x, y)) {
  98       case V.CAMEL:
  99         return this.getPotentialCamelMoves([x, y]);
 100       case V.WILDEBEEST:
 101         return this.getPotentialWildebeestMoves([x, y]);
 102       default:
 103         return super.getPotentialMovesFrom([x, y]);
 104     }
 105   }
 106
 107   // Pawns jump 2 or 3 squares, and promote to queen or wildebeest
 108   getPotentialPawnMoves([x, y]) {
 109     const color = this.turn;
 110     let moves = [];
 111     const [sizeX, sizeY] = [V.size.x, V.size.y];
 112     const shiftX = color == "w" ? -1 : 1;
 113     const startRanks = color == "w" ? [sizeX - 2, sizeX - 3] : [1, 2];
 114     const lastRank = color == "w" ? 0 : sizeX - 1;
 115     const finalPieces = x + shiftX == lastRank
 116       ? [V.WILDEBEEST, V.QUEEN]
 117       : [V.PAWN];
 118
 119     if (this.board[x + shiftX][y] == V.EMPTY) {
 120       // One square forward
 121       for (let piece of finalPieces)
 122         moves.push(
 123           this.getBasicMove([x, y], [x + shiftX, y], { c: color, p: piece })
 124         );
 125       if (startRanks.includes(x)) {
 126         if (this.board[x + 2 * shiftX][y] == V.EMPTY) {
 127           // Two squares jump
 128           moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
 129           if (x == startRanks[0] && this.board[x + 3 * shiftX][y] == V.EMPTY) {
 130             // Three squares jump
 131             moves.push(this.getBasicMove([x, y], [x + 3 * shiftX, y]));
 132           }
 133         }
 134       }
 135     }
 136     // Captures
 137     for (let shiftY of [-1, 1]) {
 138       if (
 139         y + shiftY >= 0 &&
 140         y + shiftY < sizeY &&
 141         this.board[x + shiftX][y + shiftY] != V.EMPTY &&
 142         this.canTake([x, y], [x + shiftX, y + shiftY])
 143       ) {
 144         for (let piece of finalPieces) {
 145           moves.push(
 146             this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
 147               c: color,
 148               p: piece
 149             })
 150           );
 151         }
 152       }
 153     }
 154
 155     // En passant
 156     const Lep = this.epSquares.length;
 157     const epSquare = this.epSquares[Lep - 1];
 158     if (!!epSquare) {
 159       for (let epsq of epSquare) {
 160         // TODO: some redundant checks
 161         if (epsq.x == x + shiftX && Math.abs(epsq.y - y) == 1) {
 162           var enpassantMove = this.getBasicMove([x, y], [epsq.x, epsq.y]);
 163           // WARNING: the captured pawn may be diagonally behind us,
 164           // if it's a 3-squares jump and we take on 1st passing square
 165           const px = this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX;
 166           enpassantMove.vanish.push({
 167             x: px,
 168             y: epsq.y,
 169             p: "p",
 170             c: this.getColor(px, epsq.y)
 171           });
 172           moves.push(enpassantMove);
 173         }
 174       }
 175     }
 176
 177     return moves;
 178   }
 179
 180   // TODO: wildebeest castle
 181
 182   getPotentialCamelMoves(sq) {
 183     return this.getSlideNJumpMoves(sq, V.steps[V.CAMEL], "oneStep");
 184   }
 185
 186   getPotentialWildebeestMoves(sq) {
 187     return this.getSlideNJumpMoves(
 188       sq,
 189       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 190       "oneStep"
 191     );
 192   }
 193
 194   isAttacked(sq, color) {
 195     return (
 196       super.isAttacked(sq, color) ||
 197       this.isAttackedByCamel(sq, color) ||
 198       this.isAttackedByWildebeest(sq, color)
 199     );
 200   }
 201
 202   isAttackedByCamel(sq, color) {
 203     return this.isAttackedBySlideNJump(
 204       sq,
 205       color,
 206       V.CAMEL,
 207       V.steps[V.CAMEL],
 208       "oneStep"
 209     );
 210   }
 211
 212   isAttackedByWildebeest(sq, color) {
 213     return this.isAttackedBySlideNJump(
 214       sq,
 215       color,
 216       V.WILDEBEEST,
 217       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 218       "oneStep"
 219     );
 220   }
 221
 222   getCurrentScore() {
 223     if (this.atLeastOneMove()) return "*";
 224     // No valid move: game is lost (stalemate is a win)
 225     return this.turn == "w" ? "0-1" : "1-0";
 226   }
 227
 228   static get VALUES() {
 229     return Object.assign(
 230       { c: 3, w: 7 }, //experimental
 231       ChessRules.VALUES
 232     );
 233   }
 234
 235   static get SEARCH_DEPTH() {
 236     return 2;
 237   }
 238
 239   static GenRandInitFen(randomness) {
 240     if (!randomness) randomness = 2;
 241     if (randomness == 0) {
 242       return (
 243         "rnccwkqbbnr/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/RNBBQKWCCNR " +
 244         "w 0 akak -"
 245       );
 246     }
 247
 248     let pieces = { w: new Array(11), b: new Array(11) };
 249     let flags = "";
 250     for (let c of ["w", "b"]) {
 251       if (c == 'b' && randomness == 1) {
 252         pieces['b'] = pieces['w'];
 253         flags += flags;
 254         break;
 255       }
 256
 257       let positions = ArrayFun.range(11);
 258
 259       // Get random squares for bishops + camels (different colors)
 260       let randIndexes = sample(ArrayFun.range(6), 2).map(i => {
 261         return 2 * i;
 262       });
 263       let bishop1Pos = positions[randIndexes[0]];
 264       let camel1Pos = positions[randIndexes[1]];
 265       // The second bishop (camel) must be on a square of different color
 266       let randIndexes_tmp = sample(ArrayFun.range(5), 2).map(i => {
 267         return 2 * i + 1;
 268       });
 269       let bishop2Pos = positions[randIndexes_tmp[0]];
 270       let camel2Pos = positions[randIndexes_tmp[1]];
 271       for (let idx of randIndexes.concat(randIndexes_tmp).sort((a, b) => {
 272         return b - a;
 273       })) {
 274         // Largest indices first
 275         positions.splice(idx, 1);
 276       }
 277
 278       let randIndex = randInt(7);
 279       let knight1Pos = positions[randIndex];
 280       positions.splice(randIndex, 1);
 281       randIndex = randInt(6);
 282       let knight2Pos = positions[randIndex];
 283       positions.splice(randIndex, 1);
 284
 285       randIndex = randInt(5);
 286       let queenPos = positions[randIndex];
 287       positions.splice(randIndex, 1);
 288
 289       // Random square for wildebeest
 290       randIndex = randInt(4);
 291       let wildebeestPos = positions[randIndex];
 292       positions.splice(randIndex, 1);
 293
 294       let rook1Pos = positions[0];
 295       let kingPos = positions[1];
 296       let rook2Pos = positions[2];
 297
 298       pieces[c][rook1Pos] = "r";
 299       pieces[c][knight1Pos] = "n";
 300       pieces[c][bishop1Pos] = "b";
 301       pieces[c][queenPos] = "q";
 302       pieces[c][camel1Pos] = "c";
 303       pieces[c][camel2Pos] = "c";
 304       pieces[c][wildebeestPos] = "w";
 305       pieces[c][kingPos] = "k";
 306       pieces[c][bishop2Pos] = "b";
 307       pieces[c][knight2Pos] = "n";
 308       pieces[c][rook2Pos] = "r";
 309       flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos);
 310     }
 311     return (
 312       pieces["b"].join("") +
 313       "/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/" +
 314       pieces["w"].join("").toUpperCase() +
 315       " w 0 " + flags + " -"
 316     );
 317   }
 318 };