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     const oppCol = V.GetOppCol(color);
  13     for (let i = 0; i < V.size.x; i++) {
  14       for (let j = 0; j < V.size.y; j++) {
  15         if (
  16           this.board[i][j] != V.EMPTY &&
  17           this.getColor(i, j) != oppCol &&
  18           this.filterValid(this.getPotentialMovesFrom([i, j])).some(m =>
  19             // Warning: discard castle moves
  20             m.vanish.length == 2 && m.appear.length == 1)
  21         ) {
  22           return true;
  23         }
  24       }
  25     }
  26     return false;
  27   }
  28
  29   getPossibleMovesFrom(sq) {
  30     let moves = this.filterValid(this.getPotentialMovesFrom(sq));
  31     const captureMoves = V.KeepCaptures(moves);
  32     if (captureMoves.length > 0) return captureMoves;
  33     if (this.atLeastOneCapture()) return [];
  34     return moves;
  35   }
  36
  37   getAllValidMoves() {
  38     const moves = super.getAllValidMoves();
  39     if (moves.some(m => m.vanish.length == 2 && m.appear.length == 1))
  40       return V.KeepCaptures(moves);
  41     return moves;
  42   }
  43 };