client/src/variants/Balaklava.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 export class BalaklavaRules extends ChessRules {
   4   static get PawnSpecs() {
   5     return Object.assign(
   6       {},
   7       ChessRules.PawnSpecs,
   8       { promotions: [V.ROOK, V.MAMMOTH, V.BISHOP, V.QUEEN] }
   9     );
  10   }
  11
  12   static get HasEnpassant() {
  13     return false;
  14   }
  15
  16   getPpath(b) {
  17     return (b[1] == V.MAMMOTH ? "Balaklava/" : "") + b;
  18   }
  19
  20   // Alfil + Dabbaba:
  21   static get MAMMOTH() {
  22     return "m";
  23   }
  24
  25   static get PIECES() {
  26     return [V.PAWN, V.ROOK, V.MAMMOTH, V.BISHOP, V.QUEEN, V.KING];
  27   }
  28
  29   static get steps() {
  30     return Object.assign(
  31       {},
  32       ChessRules.steps,
  33       {
  34         m: [
  35           [-2, -2],
  36           [-2, 0],
  37           [-2, 2],
  38           [0, -2],
  39           [0, 2],
  40           [2, -2],
  41           [2, 0],
  42           [2, 2],
  43         ]
  44       }
  45     );
  46   }
  47
  48   static GenRandInitFen(randomness) {
  49     // No collision between 'n' and castle flags, so next replacement is fine
  50     return (
  51       ChessRules.GenRandInitFen(randomness)
  52         .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], "oneStep");
  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 (
 104       this.isAttackedBySlideNJump(
 105         sq, color, V.MAMMOTH, V.steps[V.MAMMOTH], "oneStep")
 106     );
 107   }
 108
 109   static get SEARCH_DEPTH() {
 110     return 2;
 111   }
 112
 113   static get VALUES() {
 114     return Object.assign(
 115       // A mammoth is probably worth a little more than a knight
 116       { m: 4 },
 117       ChessRules.VALUES
 118     );
 119   }
 120 };