client/src/variants/Racingkings.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 export class RacingkingsRules extends ChessRules {
   4
   5   static get Options() {
   6     return null;
   7   }
   8
   9   static get HasFlags() {
  10     return false;
  11   }
  12
  13   static get HasEnpassant() {
  14     return false;
  15   }
  16
  17   static get CanFlip() {
  18     return false;
  19   }
  20
  21   static GenRandInitFen() {
  22     return "8/8/8/8/8/8/krbnNBRK/qrbnNBRQ w 0";
  23   }
  24
  25   filterValid(moves) {
  26     if (moves.length == 0) return [];
  27     const color = this.turn;
  28     const oppCol = V.GetOppCol(color);
  29     return moves.filter(m => {
  30       this.play(m);
  31       // Giving check is forbidden as well:
  32       const res = !this.underCheck(color) && !this.underCheck(oppCol);
  33       this.undo(m);
  34       return res;
  35     });
  36   }
  37
  38   getCurrentScore() {
  39     // If both kings arrived on the last rank, it's a draw
  40     if (this.kingPos['w'][0] == 0 && this.kingPos['b'][0] == 0) return "1/2";
  41     // If after my move the opponent king is on last rank, I lose.
  42     // This is only possible with black.
  43     if (this.turn == 'w' && this.kingPos['w'][0] == 0) return "1-0";
  44     // Turn has changed:
  45     const color = V.GetOppCol(this.turn);
  46     if (this.kingPos[color][0] == 0) {
  47       // The opposing edge is reached!
  48       // If color is white and the black king can arrive on 8th rank
  49       // at next move, then it should be a draw:
  50       if (color == "w" && this.kingPos['b'][0] == 1) {
  51         // Search for a move
  52         const oppKingMoves = this.filterValid(
  53           this.getPotentialKingMoves(this.kingPos['b']));
  54         if (oppKingMoves.some(m => m.end.x == 0)) return "*";
  55       }
  56       return color == "w" ? "1-0" : "0-1";
  57     }
  58     if (this.atLeastOneMove()) return "*";
  59     // Stalemate (will probably never happen)
  60     return "1/2";
  61   }
  62
  63   evalPosition() {
  64     // Count material:
  65     let evaluation = super.evalPosition();
  66     // Ponder with king position:
  67     return evaluation/5 + this.kingPos["b"][0] - this.kingPos["w"][0];
  68   }
  69
  70 };