public/javascripts/variants/Wildebeest.js

   1 class WildebeestRules extends ChessRules
   2 {
   3     static getPpath(b)
   4     {
   5         return ([V.CAMEL,V.WILDEBEEST].includes(b[1]) ? "Wildebeest/" : "") + b;
   6     }
   7
   8     static get size() { return {x:10,y:11}; }
   9
  10     static get CAMEL() { return 'c'; }
  11     static get WILDEBEEST() { return 'w'; }
  12
  13     static get PIECES()
  14     {
  15         return ChessRules.PIECES.concat([V.CAMEL,V.WILDEBEEST]);
  16     }
  17
  18     static get steps()
  19     {
  20         return Object.assign(
  21             ChessRules.steps, //add camel moves:
  22             {'c': [ [-3,-1],[-3,1],[-1,-3],[-1,3],[1,-3],[1,3],[3,-1],[3,1] ]}
  23         );
  24     }
  25
  26     static IsGoodEnpassant(enpassant)
  27     {
  28         if (enpassant != "-")
  29         {
  30             const squares = enpassant.split(",");
  31             if (squares.length > 2)
  32                 return false;
  33             for (let sq of squares)
  34             {
  35                 const ep = V.SquareToCoords(sq);
  36                 if (isNaN(ep.x) || !V.OnBoard(ep))
  37                     return false;
  38             }
  39         }
  40         return true;
  41     }
  42
  43     // There may be 2 enPassant squares (if pawn jump 3 squares)
  44     getEnpassantFen()
  45     {
  46         const L = this.epSquares.length;
  47         if (!this.epSquares[L-1])
  48             return "-"; //no en-passant
  49         let res = "";
  50         this.epSquares[L-1].forEach(sq => {
  51             res += V.CoordsToSquare(sq) + ",";
  52         });
  53         return res.slice(0,-1); //remove last comma
  54     }
  55
  56     // En-passant after 2-sq or 3-sq jumps
  57     getEpSquare(moveOrSquare)
  58     {
  59         if (!moveOrSquare)
  60             return undefined;
  61         if (typeof moveOrSquare === "string")
  62         {
  63             const square = moveOrSquare;
  64             if (square == "-")
  65                 return undefined;
  66             let res = [];
  67             square.split(",").forEach(sq => {
  68                 res.push(V.SquareToCoords(sq));
  69             });
  70             return res;
  71         }
  72         // Argument is a move:
  73         const move = moveOrSquare;
  74         const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x];
  75         if (this.getPiece(sx,sy) == V.PAWN && Math.abs(sx - ex) >= 2)
  76         {
  77             const step = (ex-sx) / Math.abs(ex-sx);
  78             let res = [{
  79                 x: sx + step,
  80                 y: sy
  81             }];
  82             if (sx + 2*step != ex) //3-squares move
  83             {
  84                 res.push({
  85                     x: sx + 2*step,
  86                     y: sy
  87                 });
  88             }
  89             return res;
  90         }
  91         return undefined; //default
  92     }
  93
  94     getPotentialMovesFrom([x,y])
  95     {
  96         switch (this.getPiece(x,y))
  97         {
  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     {
 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 lastRank = (color == "w" ? 0 : sizeX-1);
 116         const finalPieces = x + shiftX == lastRank
 117             ? [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN]
 118             : [V.PAWN];
 119
 120         if (this.board[x+shiftX][y] == V.EMPTY)
 121         {
 122             // One square forward
 123             for (let piece of finalPieces)
 124                 moves.push(this.getBasicMove([x,y], [x+shiftX,y], {c:color,p:piece}));
 125             if (startRanks.includes(x))
 126             {
 127                 if (this.board[x+2*shiftX][y] == V.EMPTY)
 128                 {
 129                     // Two squares jump
 130                     moves.push(this.getBasicMove([x,y], [x+2*shiftX,y]));
 131                     if (x==startRanks[0] && this.board[x+3*shiftX][y] == V.EMPTY)
 132                     {
 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         {
 142             if (y + shiftY >= 0 && y + shiftY < sizeY
 143                 && this.board[x+shiftX][y+shiftY] != V.EMPTY
 144                 && this.canTake([x,y], [x+shiftX,y+shiftY]))
 145             {
 146                 for (let piece of finalPieces)
 147                 {
 148                     moves.push(this.getBasicMove([x,y], [x+shiftX,y+shiftY],
 149                         {c:color,p:piece}));
 150                 }
 151             }
 152         }
 153
 154         // En passant
 155         const Lep = this.epSquares.length;
 156         const epSquare = this.epSquares[Lep-1];
 157         if (!!epSquare)
 158         {
 159             for (let epsq of epSquare)
 160             {
 161                 // TODO: some redundant checks
 162                 if (epsq.x == x+shiftX && Math.abs(epsq.y - y) == 1)
 163                 {
 164                     var enpassantMove = this.getBasicMove([x,y], [epsq.x,epsq.y]);
 165                     // WARNING: the captured pawn may be diagonally behind us,
 166                     // if it's a 3-squares jump and we take on 1st passing square
 167                     const px = (this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX);
 168                     enpassantMove.vanish.push({
 169                         x: px,
 170                         y: epsq.y,
 171                         p: 'p',
 172                         c: this.getColor(px,epsq.y)
 173                     });
 174                     moves.push(enpassantMove);
 175                 }
 176             }
 177         }
 178
 179         return moves;
 180     }
 181
 182     // TODO: wildebeest castle
 183
 184     getPotentialCamelMoves(sq)
 185     {
 186         return this.getSlideNJumpMoves(sq, V.steps[V.CAMEL], "oneStep");
 187     }
 188
 189     getPotentialWildebeestMoves(sq)
 190     {
 191         return this.getSlideNJumpMoves(
 192             sq, V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]), "oneStep");
 193     }
 194
 195     isAttacked(sq, colors)
 196     {
 197         return super.isAttacked(sq, colors)
 198             || this.isAttackedByCamel(sq, colors)
 199             || this.isAttackedByWildebeest(sq, colors);
 200     }
 201
 202     isAttackedByCamel(sq, colors)
 203     {
 204         return this.isAttackedBySlideNJump(sq, colors,
 205             V.CAMEL, V.steps[V.CAMEL], "oneStep");
 206     }
 207
 208     isAttackedByWildebeest(sq, colors)
 209     {
 210         return this.isAttackedBySlideNJump(sq, colors, V.WILDEBEEST,
 211             V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]), "oneStep");
 212     }
 213
 214     checkGameEnd()
 215     {
 216         // No valid move: game is lost (stalemate is a win)
 217         return this.turn == "w" ? "0-1" : "1-0";
 218     }
 219
 220     static get VALUES() {
 221         return Object.assign(
 222             ChessRules.VALUES,
 223             {'c': 3, 'w': 7} //experimental
 224         );
 225     }
 226
 227     static get SEARCH_DEPTH() { return 2; }
 228
 229     static GenRandInitFen()
 230     {
 231         let pieces = { "w": new Array(10), "b": new Array(10) };
 232         for (let c of ["w","b"])
 233         {
 234             let positions = _.range(11);
 235
 236             // Get random squares for bishops + camels (different colors)
 237             let randIndexes = _.sample(_.range(6), 2).map(i => { return 2*i; });
 238             let bishop1Pos = positions[randIndexes[0]];
 239             let camel1Pos = positions[randIndexes[1]];
 240             // The second bishop (camel) must be on a square of different color
 241             let randIndexes_tmp = _.sample(_.range(5), 2).map(i => { return 2*i+1; });
 242             let bishop2Pos = positions[randIndexes_tmp[0]];
 243             let camel2Pos = positions[randIndexes_tmp[1]];
 244             for (let idx of randIndexes.concat(randIndexes_tmp)
 245                 .sort((a,b) => { return b-a; })) //largest indices first
 246             {
 247                 positions.splice(idx, 1);
 248             }
 249
 250             let randIndex = _.random(6);
 251             let knight1Pos = positions[randIndex];
 252             positions.splice(randIndex, 1);
 253             randIndex = _.random(5);
 254             let knight2Pos = positions[randIndex];
 255             positions.splice(randIndex, 1);
 256
 257             randIndex = _.random(4);
 258             let queenPos = positions[randIndex];
 259             positions.splice(randIndex, 1);
 260
 261             // Random square for wildebeest
 262             randIndex = _.random(3);
 263             let wildebeestPos = positions[randIndex];
 264             positions.splice(randIndex, 1);
 265
 266             let rook1Pos = positions[0];
 267             let kingPos = positions[1];
 268             let rook2Pos = positions[2];
 269
 270             pieces[c][rook1Pos] = 'r';
 271             pieces[c][knight1Pos] = 'n';
 272             pieces[c][bishop1Pos] = 'b';
 273             pieces[c][queenPos] = 'q';
 274             pieces[c][camel1Pos] = 'c';
 275             pieces[c][camel2Pos] = 'c';
 276             pieces[c][wildebeestPos] = 'w';
 277             pieces[c][kingPos] = 'k';
 278             pieces[c][bishop2Pos] = 'b';
 279             pieces[c][knight2Pos] = 'n';
 280             pieces[c][rook2Pos] = 'r';
 281         }
 282         return pieces["b"].join("") +
 283             "/ppppppppppp/11/11/11/11/11/11/PPPPPPPPPPP/" +
 284             pieces["w"].join("").toUpperCase() +
 285             " w 1111 -";
 286     }
 287 }
 288
 289 const VariantRules = WildebeestRules;