client/src/variants/Relayup.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 // Pawns relayed by one square at a time (but with relaying piece movements)
   4 // diff from https://www.chessvariants.com/rules/relay-chess ==> new name
   5 export class RelayupRules extends ChessRules {
   6
   7   static get PawnSpecs() {
   8     return Object.assign(
   9       {},
  10       ChessRules.PawnSpecs,
  11       { twoSquares: false }
  12     );
  13   }
  14
  15   static get HasFlags() {
  16     return false;
  17   }
  18
  19   static get HasEnpassant() {
  20     return false;
  21   }
  22
  23   getPotentialMovesFrom([x, y]) {
  24     let moves = super.getPotentialMovesFrom([x, y]);
  25     // Expand potential moves if guarded by friendly pieces.
  26     // NOTE: pawns cannot be promoted through a relaying move
  27     const piece = this.getPiece(x,y);
  28     const color = this.turn;
  29     const lastRank = (color == 'w' ? 0 : 7);
  30     const sq = [x, y];
  31     const oneStep = (piece == V.PAWN);
  32     let guardedBy = {};
  33     if (piece != V.ROOK && super.isAttackedByRook(sq, color))
  34       guardedBy[V.ROOK] = true;
  35     if (piece != V.KNIGHT && super.isAttackedByKnight(sq, color))
  36       guardedBy[V.KNIGHT] = true;
  37     if (piece != V.BISHOP && super.isAttackedByBishop(sq, color))
  38       guardedBy[V.BISHOP] = true;
  39     if (piece != V.QUEEN && super.isAttackedByQueen(sq, color))
  40       guardedBy[V.QUEEN] = true;
  41     if (piece != V.KING && super.isAttackedByKing(sq, color))
  42       guardedBy[V.KING] = true;
  43     Object.keys(guardedBy).forEach(pg => {
  44       let steps = null;
  45       if ([V.ROOK, V.KNIGHT, V.BISHOP].includes(pg)) steps = V.steps[pg];
  46       else steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
  47       const extraMoves =
  48         super.getSlideNJumpMoves(
  49           sq, steps, oneStep || [V.KNIGHT, V.KING].includes(pg))
  50         .filter(m => {
  51           return (
  52             (piece != V.PAWN || m.end.x != lastRank) &&
  53             (moves.every(mv => mv.end.x != m.end.x || mv.end.y != m.end.y))
  54           );
  55         });
  56       moves = moves.concat(extraMoves);
  57     });
  58     return moves;
  59   }
  60
  61   filterValid(moves) {
  62     return moves;
  63   }
  64   getCheckSquares() {
  65     return [];
  66   }
  67
  68   postPlay(move) {
  69     super.postPlay(move);
  70     if (move.vanish.length == 2 && move.vanish[1].p == V.KING)
  71       this.kingPos[move.vanish[1].c] = [-1, -1];
  72   }
  73
  74   postUndo(move) {
  75     super.postUndo(move);
  76     if (move.vanish.length == 2 && move.vanish[1].p == V.KING) {
  77       const v = move.vanish[1];
  78       this.kingPos[v.c] = [v.x, v.y];
  79     }
  80   }
  81
  82   getCurrentScore() {
  83     const c = this.turn;
  84     if (this.kingPos[c][0] < 0) return (c == 'w' ? "0-1" : "1-0");
  85     // It seems that there is always a possible move (TODO: check this)
  86     return "*";
  87   }
  88
  89   getNotation(move) {
  90     // Translate final and initial square
  91     const initSquare = V.CoordsToSquare(move.start);
  92     const finalSquare = V.CoordsToSquare(move.end);
  93     const piece = this.getPiece(move.start.x, move.start.y);
  94
  95     // Since pieces and pawns could move like knight,
  96     // indicate start and end squares
  97     let notation =
  98       piece.toUpperCase() +
  99       initSquare +
 100       (move.vanish.length > move.appear.length ? "x" : "") +
 101       finalSquare
 102
 103     if (
 104       piece == V.PAWN &&
 105       move.appear.length > 0 &&
 106       move.appear[0].p != V.PAWN
 107     ) {
 108       // Promotion
 109       notation += "=" + move.appear[0].p.toUpperCase();
 110     }
 111
 112     return notation;
 113   }
 114
 115 };