client/src/variants/Extinction.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 export class ExtinctionRules extends ChessRules {
   4
   5   static get PawnSpecs() {
   6     return Object.assign(
   7       {},
   8       ChessRules.PawnSpecs,
   9       { promotions: ChessRules.PawnSpecs.promotions.concat([V.KING]) }
  10     );
  11   }
  12
  13   static IsGoodPosition(position) {
  14     if (!ChessRules.IsGoodPosition(position)) return false;
  15     // Also check that each piece type is present
  16     const rows = position.split("/");
  17     let pieces = {};
  18     for (let row of rows) {
  19       for (let i = 0; i < row.length; i++) {
  20         if (isNaN(parseInt(row[i], 10)) && !pieces[row[i]])
  21           pieces[row[i]] = true;
  22       }
  23     }
  24     if (Object.keys(pieces).length != 12) return false;
  25     return true;
  26   }
  27
  28   setOtherVariables(fen) {
  29     super.setOtherVariables(fen);
  30     const pos = V.ParseFen(fen).position;
  31     // NOTE: no need for safety "|| []", because each piece type is present
  32     // (otherwise game is already over!)
  33     this.material = {
  34       w: {
  35         [V.KING]: pos.match(/K/g).length,
  36         [V.QUEEN]: pos.match(/Q/g).length,
  37         [V.ROOK]: pos.match(/R/g).length,
  38         [V.KNIGHT]: pos.match(/N/g).length,
  39         [V.BISHOP]: pos.match(/B/g).length,
  40         [V.PAWN]: pos.match(/P/g).length
  41       },
  42       b: {
  43         [V.KING]: pos.match(/k/g).length,
  44         [V.QUEEN]: pos.match(/q/g).length,
  45         [V.ROOK]: pos.match(/r/g).length,
  46         [V.KNIGHT]: pos.match(/n/g).length,
  47         [V.BISHOP]: pos.match(/b/g).length,
  48         [V.PAWN]: pos.match(/p/g).length
  49       }
  50     };
  51   }
  52
  53   // TODO: verify this assertion
  54   atLeastOneMove() {
  55     return true; //always at least one possible move
  56   }
  57
  58   filterValid(moves) {
  59     return moves; //there is no check
  60   }
  61
  62   getCheckSquares() {
  63     return [];
  64   }
  65
  66   postPlay(move) {
  67     super.postPlay(move);
  68     // Treat the promotion case: (not the capture part)
  69     if (move.appear[0].p != move.vanish[0].p) {
  70       this.material[move.appear[0].c][move.appear[0].p]++;
  71       this.material[move.appear[0].c][V.PAWN]--;
  72     }
  73     if (move.vanish.length == 2 && move.appear.length == 1)
  74       //capture
  75       this.material[move.vanish[1].c][move.vanish[1].p]--;
  76   }
  77
  78   postUndo(move) {
  79     super.postUndo(move);
  80     if (move.appear[0].p != move.vanish[0].p) {
  81       this.material[move.appear[0].c][move.appear[0].p]--;
  82       this.material[move.appear[0].c][V.PAWN]++;
  83     }
  84     if (move.vanish.length == 2 && move.appear.length == 1)
  85       this.material[move.vanish[1].c][move.vanish[1].p]++;
  86   }
  87
  88   getCurrentScore() {
  89     if (this.atLeastOneMove()) {
  90       // Game not over?
  91       const color = this.turn;
  92       if (
  93         Object.keys(this.material[color]).some(p => {
  94           return this.material[color][p] == 0;
  95         })
  96       ) {
  97         return this.turn == "w" ? "0-1" : "1-0";
  98       }
  99       return "*";
 100     }
 101     return this.turn == "w" ? "0-1" : "1-0"; //NOTE: currently unreachable...
 102   }
 103
 104   evalPosition() {
 105     const color = this.turn;
 106     if (
 107       Object.keys(this.material[color]).some(p => {
 108         return this.material[color][p] == 0;
 109       })
 110     ) {
 111       // Very negative (resp. positive)
 112       // if white (reps. black) pieces set is incomplete
 113       return (color == "w" ? -1 : 1) * V.INFINITY;
 114     }
 115     return super.evalPosition();
 116   }
 117
 118 };