public/javascripts/variants/Extinction.js

   1 class ExtinctionRules extends ChessRules
   2 {
   3     initVariables(fen)
   4     {
   5         super.initVariables(fen);
   6         const V = VariantRules;
   7         this.material =
   8         {
   9             "w":
  10             {
  11                 [V.KING]: 1,
  12                 [V.QUEEN]: 1,
  13                 [V.ROOK]: 2,
  14                 [V.KNIGHT]: 2,
  15                 [V.BISHOP]: 2,
  16                 [V.PAWN]: 8
  17             },
  18             "b":
  19             {
  20                 [V.KING]: 1,
  21                 [V.QUEEN]: 1,
  22                 [V.ROOK]: 2,
  23                 [V.KNIGHT]: 2,
  24                 [V.BISHOP]: 2,
  25                 [V.PAWN]: 8
  26             }
  27         };
  28     }
  29
  30     // TODO: verify this assertion
  31     atLeastOneMove()
  32     {
  33         return true; //always at least one possible move
  34     }
  35
  36     underCheck(move)
  37     {
  38         return false; //there is no check
  39     }
  40
  41     getCheckSquares(move)
  42     {
  43         return [];
  44     }
  45
  46     updateVariables(move)
  47     {
  48         super.updateVariables(move);
  49         if (move.vanish.length==2 && move.appear.length==1)
  50             this.material[move.vanish[1].c][move.vanish[1].p]--;
  51     }
  52
  53     unupdateVariables(move)
  54     {
  55         super.unupdateVariables(move);
  56         if (move.vanish.length==2 && move.appear.length==1)
  57             this.material[move.vanish[1].c][move.vanish[1].p]++;
  58     }
  59
  60     checkGameOver()
  61     {
  62         if (this.checkRepetition())
  63             return "1/2";
  64
  65         if (this.atLeastOneMove()) // game not over?
  66         {
  67             const color = this.turn;
  68             if (Object.keys(this.material[color]).some(
  69                 p => { return this.material[color][p] == 0; }))
  70             {
  71                 return this.checkGameEnd();
  72             }
  73             return "*";
  74         }
  75
  76         return this.checkGameEnd();
  77     }
  78
  79     // Very negative (resp. positive) if white (reps. black) pieces set is incomplete
  80     evalPosition()
  81     {
  82         if (this.missAkind())
  83             return (this.turn=="w"?-1:1) * VariantRules.INFINITY;
  84         return super.evalPosition();
  85     }
  86 }