client/src/variants/Racingkings.js

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