client/src/variants/Racingkings.js

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