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 lastRanks = color == "w" ? [0, 1] : [sizeX - 1, sizeX  -2];
 116     let finalPieces = [V.PAWN];
 117     if (x + shiftX == lastRanks[1])
 118       Array.prototype.push.apply(finalPieces, [V.WILDEBEEST, V.QUEEN]);
 119     else if (x + shiftX == lastRanks[0])
 120       finalPieces = [V.WILDEBEEST, V.QUEEN];
 121
 122     if (this.board[x + shiftX][y] == V.EMPTY) {
 123       // One square forward
 124       for (let piece of finalPieces)
 125         moves.push(
 126           this.getBasicMove([x, y], [x + shiftX, y], { c: color, p: piece })
 127         );
 128       if (startRanks.includes(x)) {
 129         if (this.board[x + 2 * shiftX][y] == V.EMPTY) {
 130           // Two squares jump
 131           moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
 132           if (x == startRanks[0] && this.board[x + 3 * shiftX][y] == V.EMPTY) {
 133             // Three squares jump
 134             moves.push(this.getBasicMove([x, y], [x + 3 * shiftX, y]));
 135           }
 136         }
 137       }
 138     }
 139     // Captures
 140     for (let shiftY of [-1, 1]) {
 141       if (
 142         y + shiftY >= 0 &&
 143         y + shiftY < sizeY &&
 144         this.board[x + shiftX][y + shiftY] != V.EMPTY &&
 145         this.canTake([x, y], [x + shiftX, y + shiftY])
 146       ) {
 147         for (let piece of finalPieces) {
 148           moves.push(
 149             this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
 150               c: color,
 151               p: piece
 152             })
 153           );
 154         }
 155       }
 156     }
 157
 158     // En passant
 159     const Lep = this.epSquares.length;
 160     const epSquare = this.epSquares[Lep - 1];
 161     if (!!epSquare) {
 162       for (let epsq of epSquare) {
 163         // TODO: some redundant checks
 164         if (epsq.x == x + shiftX && Math.abs(epsq.y - y) == 1) {
 165           let enpassantMove = this.getBasicMove([x, y], [epsq.x, epsq.y]);
 166           // WARNING: the captured pawn may be diagonally behind us,
 167           // if it's a 3-squares jump and we take on 1st passing square
 168           const px = this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX;
 169           enpassantMove.vanish.push({
 170             x: px,
 171             y: epsq.y,
 172             p: "p",
 173             c: this.getColor(px, epsq.y)
 174           });
 175           moves.push(enpassantMove);
 176         }
 177       }
 178     }
 179
 180     return moves;
 181   }
 182
 183   getPotentialCamelMoves(sq) {
 184     return this.getSlideNJumpMoves(sq, V.steps[V.CAMEL], 1);
 185   }
 186
 187   getPotentialWildebeestMoves(sq) {
 188     return this.getSlideNJumpMoves(
 189       sq, V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]), 1);
 190   }
 191
 192   getPPpath(m) {
 193     if (
 194       m.appear.length == 2 && m.vanish.length == 2 &&
 195       Math.abs(m.end.y - m.start.y) == 1 &&
 196       this.board[m.end.x][m.end.y] == V.EMPTY
 197     ) {
 198       // Castle, king moved by one square only, not directly onto rook
 199       return "Wildebeest/castle";
 200     }
 201     return super.getPPpath(m);
 202   }
 203
 204   // Special Wildebeest castling rules:
 205   getCastleMoves([x, y]) {
 206     const c = this.getColor(x, y);
 207     const oppCol = V.GetOppCol(c);
 208     let moves = [];
 209     let i = 0;
 210     const castlingKing = this.board[x][y].charAt(1);
 211     castlingCheck: for (
 212       let castleSide = 0;
 213       castleSide < 2;
 214       castleSide++ //"large", then "small"
 215     ) {
 216       if (this.castleFlags[c][castleSide] >= V.size.y) continue;
 217       // Rook and king are on initial position
 218       const rookPos = this.castleFlags[c][castleSide];
 219       const range = (castleSide == 0 ? [rookPos, y] : [y, rookPos]);
 220
 221       // King and rook must be connected:
 222       for (let i = range[0] + 1; i <= range[1] - 1; i++) {
 223         if (this.board[x][i] != V.EMPTY) continue castlingCheck;
 224       }
 225       const step = 2 * castleSide - 1;
 226       // No attacks on the path of the king ?
 227       for (let i = range[0]; i <= range[1]; i++) {
 228         if (i != rookPos && this.isAttacked([x, i], oppCol))
 229           continue castlingCheck;
 230         if (
 231           i != y &&
 232           // Do not end in the corner, except if starting square is too near
 233           (i > 0 || y == 1) &&
 234           (i < V.size.y - 1 || y == V.size.y - 2)
 235         ) {
 236           // Found a possible castle move:
 237           moves.push(
 238             new Move({
 239               appear: [
 240                 new PiPo({
 241                   x: x,
 242                   y: i,
 243                   p: V.KING,
 244                   c: c
 245                 }),
 246                 new PiPo({
 247                   x: x,
 248                   y: i - step,
 249                   p: V.ROOK,
 250                   c: c
 251                 })
 252               ],
 253               vanish: [
 254                 new PiPo({ x: x, y: y, p: V.KING, c: c }),
 255                 new PiPo({ x: x, y: rookPos, p: V.ROOK, c: c })
 256               ]
 257             })
 258           );
 259         }
 260       }
 261     }
 262
 263     return moves;
 264   }
 265
 266   isAttacked(sq, color) {
 267     return (
 268       super.isAttacked(sq, color) ||
 269       this.isAttackedByCamel(sq, color) ||
 270       this.isAttackedByWildebeest(sq, color)
 271     );
 272   }
 273
 274   isAttackedByCamel(sq, color) {
 275     return this.isAttackedBySlideNJump(
 276       sq, color, V.CAMEL, V.steps[V.CAMEL], 1);
 277   }
 278
 279   isAttackedByWildebeest(sq, color) {
 280     return this.isAttackedBySlideNJump(
 281       sq, color, V.WILDEBEEST, V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]), 1);
 282   }
 283
 284   getCurrentScore() {
 285     if (this.atLeastOneMove()) return "*";
 286     // No valid move: game is lost (stalemate is a win)
 287     return this.turn == "w" ? "0-1" : "1-0";
 288   }
 289
 290   static get VALUES() {
 291     return Object.assign(
 292       { c: 3, w: 7 }, //experimental
 293       ChessRules.VALUES
 294     );
 295   }
 296
 297   static get SEARCH_DEPTH() {
 298     return 2;
 299   }
 300
 301   static GenRandInitFen(options) {
 302     if (options.randomness == 0) {
 303       return (
 304         "rnccwkqbbnr/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/RNBBQKWCCNR " +
 305         "w 0 akak -"
 306       );
 307     }
 308
 309     let pieces = { w: new Array(11), b: new Array(11) };
 310     let flags = "";
 311     for (let c of ["w", "b"]) {
 312       if (c == 'b' && options.randomness == 1) {
 313         pieces['b'] = pieces['w'];
 314         flags += flags;
 315         break;
 316       }
 317
 318       let positions = ArrayFun.range(11);
 319
 320       // Get random squares for bishops + camels (different colors)
 321       let randIndexes = sample(ArrayFun.range(6), 2).map(i => {
 322         return 2 * i;
 323       });
 324       let bishop1Pos = positions[randIndexes[0]];
 325       let camel1Pos = positions[randIndexes[1]];
 326       // The second bishop (camel) must be on a square of different color
 327       let randIndexes_tmp = sample(ArrayFun.range(5), 2).map(i => {
 328         return 2 * i + 1;
 329       });
 330       let bishop2Pos = positions[randIndexes_tmp[0]];
 331       let camel2Pos = positions[randIndexes_tmp[1]];
 332       for (let idx of randIndexes.concat(randIndexes_tmp).sort((a, b) => {
 333         return b - a;
 334       })) {
 335         // Largest indices first
 336         positions.splice(idx, 1);
 337       }
 338
 339       let randIndex = randInt(7);
 340       let knight1Pos = positions[randIndex];
 341       positions.splice(randIndex, 1);
 342       randIndex = randInt(6);
 343       let knight2Pos = positions[randIndex];
 344       positions.splice(randIndex, 1);
 345
 346       randIndex = randInt(5);
 347       let queenPos = positions[randIndex];
 348       positions.splice(randIndex, 1);
 349
 350       // Random square for wildebeest
 351       randIndex = randInt(4);
 352       let wildebeestPos = positions[randIndex];
 353       positions.splice(randIndex, 1);
 354
 355       let rook1Pos = positions[0];
 356       let kingPos = positions[1];
 357       let rook2Pos = positions[2];
 358
 359       pieces[c][rook1Pos] = "r";
 360       pieces[c][knight1Pos] = "n";
 361       pieces[c][bishop1Pos] = "b";
 362       pieces[c][queenPos] = "q";
 363       pieces[c][camel1Pos] = "c";
 364       pieces[c][camel2Pos] = "c";
 365       pieces[c][wildebeestPos] = "w";
 366       pieces[c][kingPos] = "k";
 367       pieces[c][bishop2Pos] = "b";
 368       pieces[c][knight2Pos] = "n";
 369       pieces[c][rook2Pos] = "r";
 370       flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos);
 371     }
 372     return (
 373       pieces["b"].join("") +
 374       "/ppppppppppp/92/92/92/92/92/92/PPPPPPPPPPP/" +
 375       pieces["w"].join("").toUpperCase() +
 376       " w 0 " + flags + " -"
 377     );
 378   }
 379
 380 };