client/src/variants/Capture.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 export class CaptureRules extends ChessRules {
   4
   5   // Trim all non-capturing moves
   6   static KeepCaptures(moves) {
   7     return moves.filter(m => m.vanish.length == 2 && m.appear.length == 1);
   8   }
   9
  10   // Stop at the first capture found (if any)
  11   atLeastOneCapture() {
  12     const color = this.turn;
  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) == color &&
  18           this.filterValid(this.getPotentialMovesFrom([i, j])).some(m => {
  19             return (
  20               // Warning: discard castle moves
  21               m.vanish.length == 2 && m.appear.length == 1 &&
  22               this.filterValid([m]).length == 1
  23             );
  24           })
  25         ) {
  26           return true;
  27         }
  28       }
  29     }
  30     return false;
  31   }
  32
  33   getPossibleMovesFrom(sq) {
  34     let moves = this.filterValid(this.getPotentialMovesFrom(sq));
  35     const captureMoves = V.KeepCaptures(moves);
  36     if (captureMoves.length > 0) return captureMoves;
  37     if (this.atLeastOneCapture()) return [];
  38     return moves;
  39   }
  40
  41   getAllValidMoves() {
  42     const moves = super.getAllValidMoves();
  43     if (moves.some(m => m.vanish.length == 2 && m.appear.length == 1))
  44       return V.KeepCaptures(moves);
  45     return moves;
  46   }
  47
  48 };