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 != "-") {
  43       const squares = enpassant.split(",");
  44       if (squares.length > 2) return false;
  45       for (let sq of squares) {
  46         const ep = V.SquareToCoords(sq);
  47         if (isNaN(ep.x) || !V.OnBoard(ep)) return false;
  48       }
  49     }
  50     return true;
  51   }
  52
  53   getPpath(b) {
  54     return ([V.CAMEL, V.WILDEBEEST].includes(b[1]) ? "Wildebeest/" : "") + b;
  55   }
  56
  57   // There may be 2 enPassant squares (if pawn jump 3 squares)
  58   getEnpassantFen() {
  59     const L = this.epSquares.length;
  60     if (!this.epSquares[L - 1]) return "-"; //no en-passant
  61     let res = "";
  62     this.epSquares[L - 1].forEach(sq => {
  63       res += V.CoordsToSquare(sq) + ",";
  64     });
  65     return res.slice(0, -1); //remove last comma
  66   }
  67
  68   // En-passant after 2-sq or 3-sq jumps
  69   getEpSquare(moveOrSquare) {
  70     if (!moveOrSquare) return undefined;
  71     if (typeof moveOrSquare === "string") {
  72       const square = moveOrSquare;
  73       if (square == "-") return undefined;
  74       let res = [];
  75       square.split(",").forEach(sq => {
  76         res.push(V.SquareToCoords(sq));
  77       });
  78       return res;
  79     }
  80     // Argument is a move:
  81     const move = moveOrSquare;
  82     const [sx, sy, ex] = [move.start.x, move.start.y, move.end.x];
  83     if (this.getPiece(sx, sy) == V.PAWN && Math.abs(sx - ex) >= 2) {
  84       const step = (ex - sx) / Math.abs(ex - sx);
  85       let res = [
  86         {
  87           x: sx + step,
  88           y: sy
  89         }
  90       ];
  91       if (sx + 2 * step != ex) {
  92         //3-squares move
  93         res.push({
  94           x: sx + 2 * step,
  95           y: sy
  96         });
  97       }
  98       return res;
  99     }
 100     return undefined; //default
 101   }
 102
 103   getPotentialMovesFrom([x, y]) {
 104     switch (this.getPiece(x, y)) {
 105       case V.CAMEL:
 106         return this.getPotentialCamelMoves([x, y]);
 107       case V.WILDEBEEST:
 108         return this.getPotentialWildebeestMoves([x, y]);
 109       default:
 110         return super.getPotentialMovesFrom([x, y]);
 111     }
 112   }
 113
 114   // Pawns jump 2 or 3 squares, and promote to queen or wildebeest
 115   getPotentialPawnMoves([x, y]) {
 116     const color = this.turn;
 117     let moves = [];
 118     const [sizeX, sizeY] = [V.size.x, V.size.y];
 119     const shiftX = color == "w" ? -1 : 1;
 120     const startRanks = color == "w" ? [sizeX - 2, sizeX - 3] : [1, 2];
 121     const lastRank = color == "w" ? 0 : sizeX - 1;
 122     const finalPieces = x + shiftX == lastRank
 123       ? [V.WILDEBEEST, V.QUEEN]
 124       : [V.PAWN];
 125
 126     if (this.board[x + shiftX][y] == V.EMPTY) {
 127       // One square forward
 128       for (let piece of finalPieces)
 129         moves.push(
 130           this.getBasicMove([x, y], [x + shiftX, y], { c: color, p: piece })
 131         );
 132       if (startRanks.includes(x)) {
 133         if (this.board[x + 2 * shiftX][y] == V.EMPTY) {
 134           // Two squares jump
 135           moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
 136           if (x == startRanks[0] && this.board[x + 3 * shiftX][y] == V.EMPTY) {
 137             // Three squares jump
 138             moves.push(this.getBasicMove([x, y], [x + 3 * shiftX, y]));
 139           }
 140         }
 141       }
 142     }
 143     // Captures
 144     for (let shiftY of [-1, 1]) {
 145       if (
 146         y + shiftY >= 0 &&
 147         y + shiftY < sizeY &&
 148         this.board[x + shiftX][y + shiftY] != V.EMPTY &&
 149         this.canTake([x, y], [x + shiftX, y + shiftY])
 150       ) {
 151         for (let piece of finalPieces) {
 152           moves.push(
 153             this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
 154               c: color,
 155               p: piece
 156             })
 157           );
 158         }
 159       }
 160     }
 161
 162     // En passant
 163     const Lep = this.epSquares.length;
 164     const epSquare = this.epSquares[Lep - 1];
 165     if (epSquare) {
 166       for (let epsq of epSquare) {
 167         // TODO: some redundant checks
 168         if (epsq.x == x + shiftX && Math.abs(epsq.y - y) == 1) {
 169           var enpassantMove = this.getBasicMove([x, y], [epsq.x, epsq.y]);
 170           // WARNING: the captured pawn may be diagonally behind us,
 171           // if it's a 3-squares jump and we take on 1st passing square
 172           const px = this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX;
 173           enpassantMove.vanish.push({
 174             x: px,
 175             y: epsq.y,
 176             p: "p",
 177             c: this.getColor(px, epsq.y)
 178           });
 179           moves.push(enpassantMove);
 180         }
 181       }
 182     }
 183
 184     return moves;
 185   }
 186
 187   // TODO: wildebeest castle
 188
 189   getPotentialCamelMoves(sq) {
 190     return this.getSlideNJumpMoves(sq, V.steps[V.CAMEL], "oneStep");
 191   }
 192
 193   getPotentialWildebeestMoves(sq) {
 194     return this.getSlideNJumpMoves(
 195       sq,
 196       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 197       "oneStep"
 198     );
 199   }
 200
 201   isAttacked(sq, color) {
 202     return (
 203       super.isAttacked(sq, color) ||
 204       this.isAttackedByCamel(sq, color) ||
 205       this.isAttackedByWildebeest(sq, color)
 206     );
 207   }
 208
 209   isAttackedByCamel(sq, color) {
 210     return this.isAttackedBySlideNJump(
 211       sq,
 212       color,
 213       V.CAMEL,
 214       V.steps[V.CAMEL],
 215       "oneStep"
 216     );
 217   }
 218
 219   isAttackedByWildebeest(sq, color) {
 220     return this.isAttackedBySlideNJump(
 221       sq,
 222       color,
 223       V.WILDEBEEST,
 224       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 225       "oneStep"
 226     );
 227   }
 228
 229   getCurrentScore() {
 230     if (this.atLeastOneMove()) return "*";
 231     // No valid move: game is lost (stalemate is a win)
 232     return this.turn == "w" ? "0-1" : "1-0";
 233   }
 234
 235   static get VALUES() {
 236     return Object.assign(
 237       { c: 3, w: 7 }, //experimental
 238       ChessRules.VALUES
 239     );
 240   }
 241
 242   static get SEARCH_DEPTH() {
 243     return 2;
 244   }
 245
 246   static GenRandInitFen(randomness) {
 247     if (!randomness) randomness = 2;
 248     if (randomness == 0)
 249       return "rnccwkqbbnr/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/RNBBQKWCCNR w 0 akak -";
 250
 251     let pieces = { w: new Array(11), b: new Array(11) };
 252     let flags = "";
 253     for (let c of ["w", "b"]) {
 254       if (c == 'b' && randomness == 1) {
 255         pieces['b'] = pieces['w'];
 256         flags += flags;
 257         break;
 258       }
 259
 260       let positions = ArrayFun.range(11);
 261
 262       // Get random squares for bishops + camels (different colors)
 263       let randIndexes = sample(ArrayFun.range(6), 2).map(i => {
 264         return 2 * i;
 265       });
 266       let bishop1Pos = positions[randIndexes[0]];
 267       let camel1Pos = positions[randIndexes[1]];
 268       // The second bishop (camel) must be on a square of different color
 269       let randIndexes_tmp = sample(ArrayFun.range(5), 2).map(i => {
 270         return 2 * i + 1;
 271       });
 272       let bishop2Pos = positions[randIndexes_tmp[0]];
 273       let camel2Pos = positions[randIndexes_tmp[1]];
 274       for (let idx of randIndexes.concat(randIndexes_tmp).sort((a, b) => {
 275         return b - a;
 276       })) {
 277         // Largest indices first
 278         positions.splice(idx, 1);
 279       }
 280
 281       let randIndex = randInt(7);
 282       let knight1Pos = positions[randIndex];
 283       positions.splice(randIndex, 1);
 284       randIndex = randInt(6);
 285       let knight2Pos = positions[randIndex];
 286       positions.splice(randIndex, 1);
 287
 288       randIndex = randInt(5);
 289       let queenPos = positions[randIndex];
 290       positions.splice(randIndex, 1);
 291
 292       // Random square for wildebeest
 293       randIndex = randInt(4);
 294       let wildebeestPos = positions[randIndex];
 295       positions.splice(randIndex, 1);
 296
 297       let rook1Pos = positions[0];
 298       let kingPos = positions[1];
 299       let rook2Pos = positions[2];
 300
 301       pieces[c][rook1Pos] = "r";
 302       pieces[c][knight1Pos] = "n";
 303       pieces[c][bishop1Pos] = "b";
 304       pieces[c][queenPos] = "q";
 305       pieces[c][camel1Pos] = "c";
 306       pieces[c][camel2Pos] = "c";
 307       pieces[c][wildebeestPos] = "w";
 308       pieces[c][kingPos] = "k";
 309       pieces[c][bishop2Pos] = "b";
 310       pieces[c][knight2Pos] = "n";
 311       pieces[c][rook2Pos] = "r";
 312       flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos);
 313     }
 314     return (
 315       pieces["b"].join("") +
 316       "/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/" +
 317       pieces["w"].join("").toUpperCase() +
 318       " w 0 " + flags + " -"
 319     );
 320   }
 321 };