client/src/variants/Balaklava.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 export class BalaklavaRules extends ChessRules {
   4
   5   static get PawnSpecs() {
   6     return Object.assign(
   7       {},
   8       ChessRules.PawnSpecs,
   9       { promotions: [V.ROOK, V.MAMMOTH, V.BISHOP, V.QUEEN] }
  10     );
  11   }
  12
  13   static get HasEnpassant() {
  14     return false;
  15   }
  16
  17   getPpath(b) {
  18     return (b[1] == V.MAMMOTH ? "Balaklava/" : "") + b;
  19   }
  20
  21   // Alfil + Dabbaba:
  22   static get MAMMOTH() {
  23     return "m";
  24   }
  25
  26   static get PIECES() {
  27     return [V.PAWN, V.ROOK, V.MAMMOTH, V.BISHOP, V.QUEEN, V.KING];
  28   }
  29
  30   static get steps() {
  31     return Object.assign(
  32       {},
  33       ChessRules.steps,
  34       {
  35         m: [
  36           [-2, -2],
  37           [-2, 0],
  38           [-2, 2],
  39           [0, -2],
  40           [0, 2],
  41           [2, -2],
  42           [2, 0],
  43           [2, 2],
  44         ]
  45       }
  46     );
  47   }
  48
  49   static GenRandInitFen(options) {
  50     // No collision between 'n' and castle flags, so next replacement is fine
  51     return (
  52       ChessRules.GenRandInitFen(options).replace(/n/g, 'm').replace(/N/g, 'M')
  53     );
  54   }
  55
  56   getPotentialMovesFrom([x, y]) {
  57     const piece = this.getPiece(x, y);
  58     let moves =
  59       piece == V.MAMMOTH
  60         ? this.getPotentialMammothMoves([x, y])
  61         : super.getPotentialMovesFrom([x, y]);
  62     if (piece != V.KING) {
  63       // Add non-capturing knight movements
  64       const color = this.turn;
  65       const lastRank = (color == 'w' ? 0 : 7);
  66       V.steps[V.KNIGHT].forEach(step => {
  67         // Pawns cannot go backward:
  68         if (
  69           piece == V.PAWN &&
  70           (
  71             (color == 'w' && step[0] > 0) ||
  72             (color == 'b' && step[0] < 0)
  73           )
  74         ) {
  75           return;
  76         }
  77         const [i, j] = [x + step[0], y + step[1]];
  78         if (
  79           V.OnBoard(i, j) &&
  80           this.board[i][j] == V.EMPTY &&
  81           // Pawns don't promote with a knight move
  82           (piece != V.PAWN || i != lastRank)
  83         ) {
  84           moves.push(this.getBasicMove([x, y], [i, j]));
  85         }
  86       });
  87     }
  88     return moves;
  89   }
  90
  91   getPotentialMammothMoves(sq) {
  92     return this.getSlideNJumpMoves(sq, V.steps[V.MAMMOTH], 1);
  93   }
  94
  95   isAttacked(sq, color) {
  96     return (
  97       super.isAttacked(sq, color) ||
  98       this.isAttackedByMammoth(sq, color)
  99     );
 100   }
 101
 102   isAttackedByMammoth(sq, color) {
 103     return this.isAttackedBySlideNJump(
 104       sq, color, V.MAMMOTH, V.steps[V.MAMMOTH], 1);
 105   }
 106
 107   static get SEARCH_DEPTH() {
 108     return 2;
 109   }
 110
 111   static get VALUES() {
 112     return Object.assign(
 113       // A mammoth is probably worth a little more than a knight
 114       { m: 4 },
 115       ChessRules.VALUES
 116     );
 117   }
 118
 119 };