public/javascripts/variants/Antiking.js

   1 class AntikingRules extends ChessRules
   2 {
   3     // Path to pieces
   4     static getPpath(b)
   5     {
   6         return b[1]=='a' ? "Antiking/"+b : b;
   7     }
   8
   9     static get ANTIKING() { return 'a'; }
  10
  11     initVariables(fen)
  12     {
  13         super.initVariables(fen);
  14         this.antikingPos = {'w':[-1,-1], 'b':[-1,-1]};
  15         const position = fen.split(" ")[0].split("/");
  16         for (let i=0; i<position.length; i++)
  17         {
  18             let k = 0;
  19             for (let j=0; j<position[i].length; j++)
  20             {
  21                 switch (position[i].charAt(j))
  22                 {
  23                     case 'a':
  24                         this.antikingPos['b'] = [i,k];
  25                         break;
  26                     case 'A':
  27                         this.antikingPos['w'] = [i,k];
  28                         break;
  29                     default:
  30                         let num = parseInt(position[i].charAt(j));
  31                         if (!isNaN(num))
  32                             k += (num-1);
  33                 }
  34                 k++;
  35             }
  36         }
  37     }
  38
  39     canTake([x1,y1], [x2,y2])
  40     {
  41         const piece1 = this.getPiece(x1,y1);
  42         const piece2 = this.getPiece(x2,y2);
  43         const color1 = this.getColor(x1,y1);
  44         const color2 = this.getColor(x2,y2);
  45         return piece2 != "a" &&
  46             ((piece1 != "a" && color1 != color2) || (piece1 == "a" && color1 == color2));
  47     }
  48
  49     getPotentialMovesFrom([x,y])
  50     {
  51         switch (this.getPiece(x,y))
  52         {
  53             case VariantRules.ANTIKING:
  54                 return this.getPotentialAntikingMoves([x,y]);
  55             default:
  56                 return super.getPotentialMovesFrom([x,y]);
  57         }
  58     }
  59
  60     getPotentialAntikingMoves(sq)
  61     {
  62         const V = VariantRules;
  63         return this.getSlideNJumpMoves(sq,
  64             V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
  65     }
  66
  67     isAttacked(sq, colors)
  68     {
  69         return (super.isAttacked(sq, colors) || this.isAttackedByAntiking(sq, colors));
  70     }
  71
  72     isAttackedByKing([x,y], colors)
  73     {
  74         const V = VariantRules;
  75         if (this.getPiece(x,y) == V.ANTIKING)
  76             return false; //antiking is not attacked by king
  77         return this.isAttackedBySlideNJump([x,y], colors, V.KING,
  78             V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
  79     }
  80
  81     isAttackedByAntiking([x,y], colors)
  82     {
  83         const V = VariantRules;
  84         if ([V.KING,V.ANTIKING].includes(this.getPiece(x,y)))
  85             return false; //(anti)king is not attacked by antiking
  86         return this.isAttackedBySlideNJump([x,y], colors, V.ANTIKING,
  87             V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
  88     }
  89
  90     underCheck(move)
  91     {
  92         const c = this.turn;
  93         const oppCol = this.getOppCol(c);
  94         this.play(move)
  95         let res = this.isAttacked(this.kingPos[c], [oppCol])
  96             || !this.isAttacked(this.antikingPos[c], [oppCol]);
  97         this.undo(move);
  98         return res;
  99     }
 100
 101     getCheckSquares(move)
 102     {
 103         let res = super.getCheckSquares(move);
 104         this.play(move);
 105         const c = this.turn;
 106         if (!this.isAttacked(this.antikingPos[c], [this.getOppCol(c)]))
 107             res.push(JSON.parse(JSON.stringify(this.antikingPos[c])));
 108         this.undo(move);
 109         return res;
 110     }
 111
 112     updateVariables(move)
 113     {
 114         super.updateVariables(move);
 115         const piece = this.getPiece(move.start.x,move.start.y);
 116         const c = this.getColor(move.start.x,move.start.y);
 117         // Update antiking position
 118         if (piece == VariantRules.ANTIKING)
 119         {
 120             this.antikingPos[c][0] = move.appear[0].x;
 121             this.antikingPos[c][1] = move.appear[0].y;
 122         }
 123     }
 124
 125     unupdateVariables(move)
 126     {
 127         super.unupdateVariables(move);
 128         const c = this.getColor(move.start.x,move.start.y);
 129         if (this.getPiece(move.start.x,move.start.y) == VariantRules.ANTIKING)
 130             this.antikingPos[c] = [move.start.x, move.start.y];
 131     }
 132
 133     checkGameEnd()
 134     {
 135         const color = this.turn;
 136         const oppCol = this.getOppCol(color);
 137         if (!this.isAttacked(this.kingPos[color], [oppCol])
 138             && this.isAttacked(this.antikingPos[color], [oppCol]))
 139         {
 140             return "1/2";
 141         }
 142         return color == "w" ? "0-1" : "1-0";
 143     }
 144
 145     // Pieces values (TODO: use Object.assign() + ChessRules.VALUES ?)
 146     static get VALUES() {
 147         return {
 148             'p': 1,
 149             'r': 5,
 150             'n': 3,
 151             'b': 3,
 152             'q': 9,
 153             'k': 1000,
 154             'a': 1000
 155         };
 156     }
 157
 158     static GenRandInitFen()
 159     {
 160         let pieces = { "w": new Array(8), "b": new Array(8) };
 161         let antikingPos = { "w": -1, "b": -1 };
 162         for (let c of ["w","b"])
 163         {
 164             let positions = _.range(8);
 165
 166             // Get random squares for bishops, but avoid corners; because,
 167             // if an antiking blocks a cornered bishop, it can never be checkmated
 168             let randIndex = 2 * _.random(1,3);
 169             const bishop1Pos = positions[randIndex];
 170             let randIndex_tmp = 2 * _.random(2) + 1;
 171             const bishop2Pos = positions[randIndex_tmp];
 172             positions.splice(Math.max(randIndex,randIndex_tmp), 1);
 173             positions.splice(Math.min(randIndex,randIndex_tmp), 1);
 174
 175             randIndex = _.random(5);
 176             const knight1Pos = positions[randIndex];
 177             positions.splice(randIndex, 1);
 178             randIndex = _.random(4);
 179             const knight2Pos = positions[randIndex];
 180             positions.splice(randIndex, 1);
 181
 182             randIndex = _.random(3);
 183             const queenPos = positions[randIndex];
 184             positions.splice(randIndex, 1);
 185
 186             const rook1Pos = positions[0];
 187             const kingPos = positions[1];
 188             const rook2Pos = positions[2];
 189
 190             // Random squares for antikings
 191             antikingPos[c] = _.random(7);
 192
 193             pieces[c][rook1Pos] = 'r';
 194             pieces[c][knight1Pos] = 'n';
 195             pieces[c][bishop1Pos] = 'b';
 196             pieces[c][queenPos] = 'q';
 197             pieces[c][kingPos] = 'k';
 198             pieces[c][bishop2Pos] = 'b';
 199             pieces[c][knight2Pos] = 'n';
 200             pieces[c][rook2Pos] = 'r';
 201         }
 202         const ranks23_black = "pppppppp/" + (antikingPos["w"]>0?antikingPos["w"]:"")
 203             + "A" + (antikingPos["w"]<7?7-antikingPos["w"]:"");
 204         const ranks23_white = (antikingPos["b"]>0?antikingPos["b"]:"") + "a"
 205             + (antikingPos["b"]<7?7-antikingPos["b"]:"") + "/PPPPPPPP";
 206         let fen = pieces["b"].join("") + "/" + ranks23_black +
 207             "/8/8/" +
 208             ranks23_white + "/" + pieces["w"].join("").toUpperCase() +
 209             " 1111"; //add flags
 210         return fen;
 211     }
 212 }