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 const VariantRules = class WildebeestRules extends ChessRules {
   6   static getPpath(b) {
   7     return ([V.CAMEL, V.WILDEBEEST].includes(b[1]) ? "Wildebeest/" : "") + b;
   8   }
   9
  10   static get size() {
  11     return { x: 10, y: 11 };
  12   }
  13
  14   static get CAMEL() {
  15     return "c";
  16   }
  17   static get WILDEBEEST() {
  18     return "w";
  19   }
  20
  21   static get PIECES() {
  22     return ChessRules.PIECES.concat([V.CAMEL, V.WILDEBEEST]);
  23   }
  24
  25   static get steps() {
  26     return Object.assign(
  27       ChessRules.steps, //add camel moves:
  28       {
  29         c: [
  30           [-3, -1],
  31           [-3, 1],
  32           [-1, -3],
  33           [-1, 3],
  34           [1, -3],
  35           [1, 3],
  36           [3, -1],
  37           [3, 1]
  38         ]
  39       }
  40     );
  41   }
  42
  43   static IsGoodEnpassant(enpassant) {
  44     if (enpassant != "-") {
  45       const squares = enpassant.split(",");
  46       if (squares.length > 2) return false;
  47       for (let sq of squares) {
  48         const ep = V.SquareToCoords(sq);
  49         if (isNaN(ep.x) || !V.OnBoard(ep)) return false;
  50       }
  51     }
  52     return true;
  53   }
  54
  55   // There may be 2 enPassant squares (if pawn jump 3 squares)
  56   getEnpassantFen() {
  57     const L = this.epSquares.length;
  58     if (!this.epSquares[L - 1]) return "-"; //no en-passant
  59     let res = "";
  60     this.epSquares[L - 1].forEach(sq => {
  61       res += V.CoordsToSquare(sq) + ",";
  62     });
  63     return res.slice(0, -1); //remove last comma
  64   }
  65
  66   // En-passant after 2-sq or 3-sq jumps
  67   getEpSquare(moveOrSquare) {
  68     if (!moveOrSquare) return undefined;
  69     if (typeof moveOrSquare === "string") {
  70       const square = moveOrSquare;
  71       if (square == "-") return undefined;
  72       let res = [];
  73       square.split(",").forEach(sq => {
  74         res.push(V.SquareToCoords(sq));
  75       });
  76       return res;
  77     }
  78     // Argument is a move:
  79     const move = moveOrSquare;
  80     const [sx, sy, ex] = [move.start.x, move.start.y, move.end.x];
  81     if (this.getPiece(sx, sy) == V.PAWN && Math.abs(sx - ex) >= 2) {
  82       const step = (ex - sx) / Math.abs(ex - sx);
  83       let res = [
  84         {
  85           x: sx + step,
  86           y: sy
  87         }
  88       ];
  89       if (sx + 2 * step != ex) {
  90         //3-squares move
  91         res.push({
  92           x: sx + 2 * step,
  93           y: sy
  94         });
  95       }
  96       return res;
  97     }
  98     return undefined; //default
  99   }
 100
 101   getPotentialMovesFrom([x, y]) {
 102     switch (this.getPiece(x, y)) {
 103       case V.CAMEL:
 104         return this.getPotentialCamelMoves([x, y]);
 105       case V.WILDEBEEST:
 106         return this.getPotentialWildebeestMoves([x, y]);
 107       default:
 108         return super.getPotentialMovesFrom([x, y]);
 109     }
 110   }
 111
 112   // Pawns jump 2 or 3 squares, and promote to queen or wildebeest
 113   getPotentialPawnMoves([x, y]) {
 114     const color = this.turn;
 115     let moves = [];
 116     const [sizeX, sizeY] = [V.size.x, V.size.y];
 117     const shiftX = color == "w" ? -1 : 1;
 118     const startRanks = color == "w" ? [sizeX - 2, sizeX - 3] : [1, 2];
 119     const lastRank = color == "w" ? 0 : sizeX - 1;
 120     const finalPieces =
 121       x + shiftX == lastRank ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN] : [V.PAWN];
 122
 123     if (this.board[x + shiftX][y] == V.EMPTY) {
 124       // One square forward
 125       for (let piece of finalPieces)
 126         moves.push(
 127           this.getBasicMove([x, y], [x + shiftX, y], { c: color, p: piece })
 128         );
 129       if (startRanks.includes(x)) {
 130         if (this.board[x + 2 * shiftX][y] == V.EMPTY) {
 131           // Two squares jump
 132           moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
 133           if (x == startRanks[0] && this.board[x + 3 * shiftX][y] == V.EMPTY) {
 134             // Three squares jump
 135             moves.push(this.getBasicMove([x, y], [x + 3 * shiftX, y]));
 136           }
 137         }
 138       }
 139     }
 140     // Captures
 141     for (let shiftY of [-1, 1]) {
 142       if (
 143         y + shiftY >= 0 &&
 144         y + shiftY < sizeY &&
 145         this.board[x + shiftX][y + shiftY] != V.EMPTY &&
 146         this.canTake([x, y], [x + shiftX, y + shiftY])
 147       ) {
 148         for (let piece of finalPieces) {
 149           moves.push(
 150             this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
 151               c: color,
 152               p: piece
 153             })
 154           );
 155         }
 156       }
 157     }
 158
 159     // En passant
 160     const Lep = this.epSquares.length;
 161     const epSquare = this.epSquares[Lep - 1];
 162     if (epSquare) {
 163       for (let epsq of epSquare) {
 164         // TODO: some redundant checks
 165         if (epsq.x == x + shiftX && Math.abs(epsq.y - y) == 1) {
 166           var enpassantMove = this.getBasicMove([x, y], [epsq.x, epsq.y]);
 167           // WARNING: the captured pawn may be diagonally behind us,
 168           // if it's a 3-squares jump and we take on 1st passing square
 169           const px = this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX;
 170           enpassantMove.vanish.push({
 171             x: px,
 172             y: epsq.y,
 173             p: "p",
 174             c: this.getColor(px, epsq.y)
 175           });
 176           moves.push(enpassantMove);
 177         }
 178       }
 179     }
 180
 181     return moves;
 182   }
 183
 184   // TODO: wildebeest castle
 185
 186   getPotentialCamelMoves(sq) {
 187     return this.getSlideNJumpMoves(sq, V.steps[V.CAMEL], "oneStep");
 188   }
 189
 190   getPotentialWildebeestMoves(sq) {
 191     return this.getSlideNJumpMoves(
 192       sq,
 193       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 194       "oneStep"
 195     );
 196   }
 197
 198   isAttacked(sq, colors) {
 199     return (
 200       super.isAttacked(sq, colors) ||
 201       this.isAttackedByCamel(sq, colors) ||
 202       this.isAttackedByWildebeest(sq, colors)
 203     );
 204   }
 205
 206   isAttackedByCamel(sq, colors) {
 207     return this.isAttackedBySlideNJump(
 208       sq,
 209       colors,
 210       V.CAMEL,
 211       V.steps[V.CAMEL],
 212       "oneStep"
 213     );
 214   }
 215
 216   isAttackedByWildebeest(sq, colors) {
 217     return this.isAttackedBySlideNJump(
 218       sq,
 219       colors,
 220       V.WILDEBEEST,
 221       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]),
 222       "oneStep"
 223     );
 224   }
 225
 226   getCurrentScore() {
 227     if (this.atLeastOneMove())
 228       // game not over
 229       return "*";
 230
 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       ChessRules.VALUES,
 238       { c: 3, w: 7 } //experimental
 239     );
 240   }
 241
 242   static get SEARCH_DEPTH() {
 243     return 2;
 244   }
 245
 246   static GenRandInitFen() {
 247     let pieces = { w: new Array(10), b: new Array(10) };
 248     for (let c of ["w", "b"]) {
 249       let positions = ArrayFun.range(11);
 250
 251       // Get random squares for bishops + camels (different colors)
 252       let randIndexes = sample(ArrayFun.range(6), 2).map(i => {
 253         return 2 * i;
 254       });
 255       let bishop1Pos = positions[randIndexes[0]];
 256       let camel1Pos = positions[randIndexes[1]];
 257       // The second bishop (camel) must be on a square of different color
 258       let randIndexes_tmp = sample(ArrayFun.range(5), 2).map(i => {
 259         return 2 * i + 1;
 260       });
 261       let bishop2Pos = positions[randIndexes_tmp[0]];
 262       let camel2Pos = positions[randIndexes_tmp[1]];
 263       for (let idx of randIndexes.concat(randIndexes_tmp).sort((a, b) => {
 264         return b - a;
 265       })) {
 266         //largest indices first
 267         positions.splice(idx, 1);
 268       }
 269
 270       let randIndex = randInt(7);
 271       let knight1Pos = positions[randIndex];
 272       positions.splice(randIndex, 1);
 273       randIndex = randInt(6);
 274       let knight2Pos = positions[randIndex];
 275       positions.splice(randIndex, 1);
 276
 277       randIndex = randInt(5);
 278       let queenPos = positions[randIndex];
 279       positions.splice(randIndex, 1);
 280
 281       // Random square for wildebeest
 282       randIndex = randInt(4);
 283       let wildebeestPos = positions[randIndex];
 284       positions.splice(randIndex, 1);
 285
 286       let rook1Pos = positions[0];
 287       let kingPos = positions[1];
 288       let rook2Pos = positions[2];
 289
 290       pieces[c][rook1Pos] = "r";
 291       pieces[c][knight1Pos] = "n";
 292       pieces[c][bishop1Pos] = "b";
 293       pieces[c][queenPos] = "q";
 294       pieces[c][camel1Pos] = "c";
 295       pieces[c][camel2Pos] = "c";
 296       pieces[c][wildebeestPos] = "w";
 297       pieces[c][kingPos] = "k";
 298       pieces[c][bishop2Pos] = "b";
 299       pieces[c][knight2Pos] = "n";
 300       pieces[c][rook2Pos] = "r";
 301     }
 302     return (
 303       pieces["b"].join("") +
 304       "/ppppppppppp/11/11/11/11/11/11/PPPPPPPPPPP/" +
 305       pieces["w"].join("").toUpperCase() +
 306       " w 0 1111 -"
 307     );
 308   }
 309 };