client/src/variants/Losers.js

   1 import { ChessRules } from "@/base_rules";
   2 import { ArrayFun } from "@/utils/array";
   3 import { randInt } from "@/utils/alea";
   4
   5 export const VariantRules = class LosersRules extends ChessRules {
   6   // Trim all non-capturing moves
   7   static KeepCaptures(moves) {
   8     return moves.filter(m => m.vanish.length == 2);
   9   }
  10
  11     // Stop at the first capture found (if any)
  12   atLeastOneCapture() {
  13     const color = this.turn;
  14     const oppCol = V.GetOppCol(color);
  15     for (let i = 0; i < V.size.x; i++) {
  16       for (let j = 0; j < V.size.y; j++) {
  17         if (
  18           this.board[i][j] != V.EMPTY &&
  19           this.getColor(i, j) != oppCol &&
  20           this.getPotentialMovesFrom([i, j]).some(m =>
  21             // Warning: duscard castle moves
  22             m.vanish.length == 2 && m.appear.length == 1)
  23         ) {
  24           return true;
  25         }
  26       }
  27     }
  28     return false;
  29   }
  30
  31   getPossibleMovesFrom(sq) {
  32     let moves = this.filterValid(this.getPotentialMovesFrom(sq));
  33     const captureMoves = V.KeepCaptures(moves);
  34     if (captureMoves.length > 0) return captureMoves;
  35     if (this.atLeastOneCapture()) return [];
  36     return moves;
  37   }
  38
  39   getAllValidMoves() {
  40     const moves = super.getAllValidMoves();
  41     if (moves.some(m => m.vanish.length == 2)) return V.KeepCaptures(moves);
  42     return moves;
  43   }
  44
  45   getCurrentScore() {
  46     // If only my king remains, I win
  47     const color = this.turn;
  48     let onlyKing = true;
  49     outerLoop: for (let i=0; i<V.size.x; i++) {
  50       for (let j=0; j<V.size.y; j++) {
  51         if (
  52           this.board[i][j] != V.EMPTY &&
  53           this.getColor(i,j) == color &&
  54           this.getPiece(i,j) != V.KING
  55         ) {
  56           onlyKing = false;
  57           break outerLoop;
  58         }
  59       }
  60     }
  61     if (onlyKing) return color == "w" ? "1-0" : "0-1";
  62     if (this.atLeastOneMove()) return "*";
  63     // No valid move: the side who cannot move (or is checkmated) wins
  64     return this.turn == "w" ? "1-0" : "0-1";
  65   }
  66
  67   static get SEARCH_DEPTH() {
  68     return 4;
  69   }
  70
  71   evalPosition() {
  72     // Less material is better (more subtle in fact but...)
  73     return -super.evalPosition();
  74   }
  75 };