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 {
   7   static getPpath(b)
   8   {
   9     return ([V.CAMEL,V.WILDEBEEST].includes(b[1]) ? "Wildebeest/" : "") + b;
  10   }
  11
  12   static get size() { return {x:10,y:11}; }
  13
  14   static get CAMEL() { return 'c'; }
  15   static get WILDEBEEST() { return 'w'; }
  16
  17   static get PIECES()
  18   {
  19     return ChessRules.PIECES.concat([V.CAMEL,V.WILDEBEEST]);
  20   }
  21
  22   static get steps()
  23   {
  24     return Object.assign(
  25       ChessRules.steps, //add camel moves:
  26       {'c': [ [-3,-1],[-3,1],[-1,-3],[-1,3],[1,-3],[1,3],[3,-1],[3,1] ]}
  27     );
  28   }
  29
  30   static IsGoodEnpassant(enpassant)
  31   {
  32     if (enpassant != "-")
  33     {
  34       const squares = enpassant.split(",");
  35       if (squares.length > 2)
  36         return false;
  37       for (let sq of squares)
  38       {
  39         const ep = V.SquareToCoords(sq);
  40         if (isNaN(ep.x) || !V.OnBoard(ep))
  41           return false;
  42       }
  43     }
  44     return true;
  45   }
  46
  47   // There may be 2 enPassant squares (if pawn jump 3 squares)
  48   getEnpassantFen()
  49   {
  50     const L = this.epSquares.length;
  51     if (!this.epSquares[L-1])
  52       return "-"; //no en-passant
  53     let res = "";
  54     this.epSquares[L-1].forEach(sq => {
  55       res += V.CoordsToSquare(sq) + ",";
  56     });
  57     return res.slice(0,-1); //remove last comma
  58   }
  59
  60   // En-passant after 2-sq or 3-sq jumps
  61   getEpSquare(moveOrSquare)
  62   {
  63     if (!moveOrSquare)
  64       return undefined;
  65     if (typeof moveOrSquare === "string")
  66     {
  67       const square = moveOrSquare;
  68       if (square == "-")
  69         return undefined;
  70       let res = [];
  71       square.split(",").forEach(sq => {
  72         res.push(V.SquareToCoords(sq));
  73       });
  74       return res;
  75     }
  76     // Argument is a move:
  77     const move = moveOrSquare;
  78     const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x];
  79     if (this.getPiece(sx,sy) == V.PAWN && Math.abs(sx - ex) >= 2)
  80     {
  81       const step = (ex-sx) / Math.abs(ex-sx);
  82       let res = [{
  83         x: sx + step,
  84         y: sy
  85       }];
  86       if (sx + 2*step != ex) //3-squares move
  87       {
  88         res.push({
  89           x: sx + 2*step,
  90           y: sy
  91         });
  92       }
  93       return res;
  94     }
  95     return undefined; //default
  96   }
  97
  98   getPotentialMovesFrom([x,y])
  99   {
 100     switch (this.getPiece(x,y))
 101     {
 102       case V.CAMEL:
 103         return this.getPotentialCamelMoves([x,y]);
 104       case V.WILDEBEEST:
 105         return this.getPotentialWildebeestMoves([x,y]);
 106       default:
 107         return super.getPotentialMovesFrom([x,y])
 108     }
 109   }
 110
 111   // Pawns jump 2 or 3 squares, and promote to queen or wildebeest
 112   getPotentialPawnMoves([x,y])
 113   {
 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 = x + shiftX == lastRank
 121       ? [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN]
 122       : [V.PAWN];
 123
 124     if (this.board[x+shiftX][y] == V.EMPTY)
 125     {
 126       // One square forward
 127       for (let piece of finalPieces)
 128         moves.push(this.getBasicMove([x,y], [x+shiftX,y], {c:color,p:piece}));
 129       if (startRanks.includes(x))
 130       {
 131         if (this.board[x+2*shiftX][y] == V.EMPTY)
 132         {
 133           // Two squares jump
 134           moves.push(this.getBasicMove([x,y], [x+2*shiftX,y]));
 135           if (x==startRanks[0] && this.board[x+3*shiftX][y] == V.EMPTY)
 136           {
 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     {
 146       if (y + shiftY >= 0 && y + shiftY < sizeY
 147         && this.board[x+shiftX][y+shiftY] != V.EMPTY
 148         && this.canTake([x,y], [x+shiftX,y+shiftY]))
 149       {
 150         for (let piece of finalPieces)
 151         {
 152           moves.push(this.getBasicMove([x,y], [x+shiftX,y+shiftY],
 153             {c:color,p:piece}));
 154         }
 155       }
 156     }
 157
 158     // En passant
 159     const Lep = this.epSquares.length;
 160     const epSquare = this.epSquares[Lep-1];
 161     if (!!epSquare)
 162     {
 163       for (let epsq of epSquare)
 164       {
 165         // TODO: some redundant checks
 166         if (epsq.x == x+shiftX && Math.abs(epsq.y - y) == 1)
 167         {
 168           var enpassantMove = this.getBasicMove([x,y], [epsq.x,epsq.y]);
 169           // WARNING: the captured pawn may be diagonally behind us,
 170           // if it's a 3-squares jump and we take on 1st passing square
 171           const px = (this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX);
 172           enpassantMove.vanish.push({
 173             x: px,
 174             y: epsq.y,
 175             p: 'p',
 176             c: this.getColor(px,epsq.y)
 177           });
 178           moves.push(enpassantMove);
 179         }
 180       }
 181     }
 182
 183     return moves;
 184   }
 185
 186   // TODO: wildebeest castle
 187
 188   getPotentialCamelMoves(sq)
 189   {
 190     return this.getSlideNJumpMoves(sq, V.steps[V.CAMEL], "oneStep");
 191   }
 192
 193   getPotentialWildebeestMoves(sq)
 194   {
 195     return this.getSlideNJumpMoves(
 196       sq, V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]), "oneStep");
 197   }
 198
 199   isAttacked(sq, colors)
 200   {
 201     return super.isAttacked(sq, colors)
 202       || this.isAttackedByCamel(sq, colors)
 203       || this.isAttackedByWildebeest(sq, colors);
 204   }
 205
 206   isAttackedByCamel(sq, colors)
 207   {
 208     return this.isAttackedBySlideNJump(sq, colors,
 209       V.CAMEL, V.steps[V.CAMEL], "oneStep");
 210   }
 211
 212   isAttackedByWildebeest(sq, colors)
 213   {
 214     return this.isAttackedBySlideNJump(sq, colors, V.WILDEBEEST,
 215       V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]), "oneStep");
 216   }
 217
 218   getCurrentScore()
 219   {
 220     if (this.atLeastOneMove()) // game not over
 221       return "*";
 222
 223     // No valid move: game is lost (stalemate is a win)
 224     return (this.turn == "w" ? "0-1" : "1-0");
 225   }
 226
 227   static get VALUES() {
 228     return Object.assign(
 229       ChessRules.VALUES,
 230       {'c': 3, 'w': 7} //experimental
 231     );
 232   }
 233
 234   static get SEARCH_DEPTH() { return 2; }
 235
 236   static GenRandInitFen()
 237   {
 238     let pieces = { "w": new Array(10), "b": new Array(10) };
 239     for (let c of ["w","b"])
 240     {
 241       let positions = ArrayFun.range(11);
 242
 243       // Get random squares for bishops + camels (different colors)
 244       let randIndexes = sample(ArrayFun.range(6), 2)
 245         .map(i => { return 2*i; });
 246       let bishop1Pos = positions[randIndexes[0]];
 247       let camel1Pos = positions[randIndexes[1]];
 248       // The second bishop (camel) must be on a square of different color
 249       let randIndexes_tmp = sample(ArrayFun.range(5), 2)
 250         .map(i => { return 2*i+1; });
 251       let bishop2Pos = positions[randIndexes_tmp[0]];
 252       let camel2Pos = positions[randIndexes_tmp[1]];
 253       for (let idx of randIndexes.concat(randIndexes_tmp)
 254         .sort((a,b) => { return b-a; })) //largest indices first
 255       {
 256         positions.splice(idx, 1);
 257       }
 258
 259       let randIndex = randInt(7);
 260       let knight1Pos = positions[randIndex];
 261       positions.splice(randIndex, 1);
 262       randIndex = randInt(6);
 263       let knight2Pos = positions[randIndex];
 264       positions.splice(randIndex, 1);
 265
 266       randIndex = randInt(5);
 267       let queenPos = positions[randIndex];
 268       positions.splice(randIndex, 1);
 269
 270       // Random square for wildebeest
 271       randIndex = randInt(4);
 272       let wildebeestPos = positions[randIndex];
 273       positions.splice(randIndex, 1);
 274
 275       let rook1Pos = positions[0];
 276       let kingPos = positions[1];
 277       let rook2Pos = positions[2];
 278
 279       pieces[c][rook1Pos] = 'r';
 280       pieces[c][knight1Pos] = 'n';
 281       pieces[c][bishop1Pos] = 'b';
 282       pieces[c][queenPos] = 'q';
 283       pieces[c][camel1Pos] = 'c';
 284       pieces[c][camel2Pos] = 'c';
 285       pieces[c][wildebeestPos] = 'w';
 286       pieces[c][kingPos] = 'k';
 287       pieces[c][bishop2Pos] = 'b';
 288       pieces[c][knight2Pos] = 'n';
 289       pieces[c][rook2Pos] = 'r';
 290     }
 291     return pieces["b"].join("") +
 292       "/ppppppppppp/11/11/11/11/11/11/PPPPPPPPPPP/" +
 293       pieces["w"].join("").toUpperCase() +
 294       " w 0 1111 -";
 295   }
 296 }