client/src/variants/Capture.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 export class CaptureRules extends ChessRules {
   4   // Trim all non-capturing moves
   5   static KeepCaptures(moves) {
   6     return moves.filter(m => m.vanish.length == 2 && m.appear.length == 1);
   7   }
   8
   9   // Stop at the first capture found (if any)
  10   atLeastOneCapture() {
  11     const color = this.turn;
  12     for (let i = 0; i < V.size.x; i++) {
  13       for (let j = 0; j < V.size.y; j++) {
  14         if (
  15           this.board[i][j] != V.EMPTY &&
  16           this.getColor(i, j) == color &&
  17           this.filterValid(this.getPotentialMovesFrom([i, j])).some(m => {
  18             return (
  19               // Warning: discard castle moves
  20               m.vanish.length == 2 && m.appear.length == 1 &&
  21               this.filterValid([m]).length == 1
  22             );
  23           })
  24         ) {
  25           return true;
  26         }
  27       }
  28     }
  29     return false;
  30   }
  31
  32   getPossibleMovesFrom(sq) {
  33     let moves = this.filterValid(this.getPotentialMovesFrom(sq));
  34     const captureMoves = V.KeepCaptures(moves);
  35     if (captureMoves.length > 0) return captureMoves;
  36     if (this.atLeastOneCapture()) return [];
  37     return moves;
  38   }
  39
  40   getAllValidMoves() {
  41     const moves = super.getAllValidMoves();
  42     if (moves.some(m => m.vanish.length == 2 && m.appear.length == 1))
  43       return V.KeepCaptures(moves);
  44     return moves;
  45   }
  46 };