public/javascripts/variants/Atomic.js

   1 class AtomicRules extends ChessRules
   2 {
   3     getPotentialMovesFrom([x,y])
   4     {
   5         let moves = super.getPotentialMovesFrom([x,y]);
   6
   7         // Handle explosions
   8         moves.forEach(m => {
   9             if (m.vanish.length > 1 && m.appear.length <= 1) //avoid castles
  10             {
  11                 // Explosion! TODO(?): drop moves which explode our king here
  12                 let steps = [ [-1,-1],[-1,0],[-1,1],[0,-1],[0,1],[1,-1],[1,0],[1,1] ];
  13                 for (let step of steps)
  14                 {
  15                     let x = m.end.x + step[0];
  16                     let y = m.end.y + step[1];
  17                     if (x>=0 && x<8 && y>=0 && y<8 && this.board[x][y] != VariantRules.EMPTY
  18                         && this.getPiece(x,y) != VariantRules.PAWN)
  19                     {
  20                         m.vanish.push(
  21                             new PiPo({p:this.getPiece(x,y),c:this.getColor(x,y),x:x,y:y}));
  22                     }
  23                 }
  24                 m.end = {x:m.appear[0].x, y:m.appear[0].y};
  25                 m.appear.pop(); //Nothin appears in this case
  26             }
  27         });
  28
  29         return moves;
  30     }
  31
  32     getPotentialKingMoves([x,y])
  33     {
  34         const V = VariantRules;
  35         // King cannot capture:
  36         let moves = [];
  37         let [sizeX,sizeY] = V.size;
  38         const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
  39         for (let step of steps)
  40         {
  41             var i = x + step[0];
  42             var j = y + step[1];
  43             if (i>=0 && i<sizeX && j>=0 && j<sizeY && this.board[i][j] == VariantRules.EMPTY)
  44                 moves.push(this.getBasicMove([x,y], [i,j]));
  45         }
  46         return moves.concat(this.getCastleMoves([x,y]));
  47     }
  48
  49     isAttacked(sq, colors)
  50     {
  51         if (this.getPiece(sq[0],sq[1]) == VariantRules.KING
  52             && this.isAttackedByKing(sq, colors))
  53         {
  54             return false; //king cannot take...
  55         }
  56         return (this.isAttackedByPawn(sq, colors)
  57             || this.isAttackedByRook(sq, colors)
  58             || this.isAttackedByKnight(sq, colors)
  59             || this.isAttackedByBishop(sq, colors)
  60             || this.isAttackedByQueen(sq, colors));
  61     }
  62
  63     updateVariables(move)
  64     {
  65         super.updateVariables(move);
  66         const color = this.getColor(move.start.x,move.start.y);
  67         if (move.appear.length == 0) //capture
  68         {
  69             const firstRank = {"w": 7, "b": 0};
  70             for (let c of ["w","b"])
  71             {
  72                 // Did we explode king of color c ? (TODO: remove move earlier)
  73                 if (Math.abs(this.kingPos[c][0]-move.end.x) <= 1
  74                     && Math.abs(this.kingPos[c][1]-move.end.y) <= 1)
  75                 {
  76                     this.kingPos[c] = [-1,-1];
  77                     this.castleFlags[c] = [false,false];
  78                 }
  79                 else
  80                 {
  81                     // Now check if init rook(s) exploded
  82                     if (Math.abs(move.end.x-firstRank[c]) <= 1)
  83                     {
  84                         if (Math.abs(move.end.y-this.INIT_COL_ROOK[c][0]) <= 1)
  85                             this.castleFlags[c][0] = false;
  86                         if (Math.abs(move.end.y-this.INIT_COL_ROOK[c][1]) <= 1)
  87                             this.castleFlags[c][1] = false;
  88                     }
  89                 }
  90             }
  91         }
  92     }
  93
  94     unupdateVariables(move)
  95     {
  96         super.unupdateVariables(move);
  97         const c = this.getColor(move.start.x,move.start.y);
  98         const oppCol = this.getOppCol(c);
  99         if ([this.kingPos[c][0],this.kingPos[oppCol][0]].some(e => { return e < 0; }))
 100         {
 101             // There is a chance that last move blowed some king away..
 102             for (let psq of move.vanish)
 103             {
 104                 if (psq.p == 'k')
 105                     this.kingPos[psq.c==c ? c : oppCol] = [psq.x, psq.y];
 106             }
 107         }
 108     }
 109
 110     underCheck(move)
 111     {
 112         const c = this.turn;
 113         const oppCol = this.getOppCol(c);
 114         this.play(move);
 115         let res = undefined;
 116         // If our king disappeared, move is not valid
 117         if (this.kingPos[c][0] < 0)
 118             res = true;
 119         // If opponent king disappeared, move is valid
 120         else if (this.kingPos[oppCol][0] < 0)
 121             res = false;
 122         // Otherwise, if we remain under check, move is not valid
 123         else
 124             res = this.isAttacked(this.kingPos[c], [oppCol]);
 125         this.undo(move);
 126         return res;
 127     }
 128
 129     getCheckSquares(move)
 130     {
 131         const c = this.getOppCol(this.turn);
 132         // King might explode:
 133         const saveKingPos = JSON.parse(JSON.stringify(this.kingPos[c]));
 134         this.play(move);
 135         let res = [ ];
 136         if (this.kingPos[c][0] < 0)
 137             res = [saveKingPos];
 138         else if (this.isAttacked(this.kingPos[c], [this.getOppCol(c)]))
 139             res = [ JSON.parse(JSON.stringify(this.kingPos[c])) ]
 140         this.undo(move);
 141         return res;
 142     }
 143
 144     checkGameEnd()
 145     {
 146         const color = this.turn;
 147         const kp = this.kingPos[color];
 148         if (kp[0] < 0) //king disappeared
 149             return color == "w" ? "0-1" : "1-0";
 150         if (!this.isAttacked(kp, [this.getOppCol(color)]))
 151             return "1/2";
 152         return color == "w" ? "0-1" : "1-0"; //checkmate
 153     }
 154 }