variants/Chaining/class.js

   1 import ChessRules from "/base_rules.js";
   2 import PiPo from "/utils/PiPo.js";
   3 import Move from "/utils/Move.js";
   4
   5 export default class ChainingRules extends ChessRules {
   6
   7   static get Options() {
   8     return {
   9       select: C.Options.select,
  10       input: C.Options.input,
  11       styles: ["atomic", "capture", "crazyhouse", "cylinder", "dark", "zen"]
  12     };
  13   }
  14
  15   get hasSelfCaptures() {
  16     return true;
  17   }
  18
  19   canSelfTake() {
  20     return true; //self captures induce chaining
  21   }
  22
  23   setOtherVariables(fenParsed, pieceArray) {
  24     super.setOtherVariables(fenParsed, pieceArray);
  25     // Stack of "last move" only for intermediate chaining
  26     this.lastMoveEnd = [];
  27   }
  28
  29   getBasicMove([sx, sy], [ex, ey], tr) {
  30     const L = this.lastMoveEnd.length;
  31     const piece = (L >= 1 ? this.lastMoveEnd[L-1].p : null);
  32     if (
  33       this.board[ex][ey] == "" ||
  34       this.getColor(ex, ey) == C.GetOppTurn(this.turn)
  35     ) {
  36       if (piece && !tr)
  37         tr = {c: this.turn, p: piece};
  38       let mv = super.getBasicMove([sx, sy], [ex, ey], tr);
  39       if (piece)
  40         mv.vanish.pop(); //end of a chain: initial piece remains
  41       return mv;
  42     }
  43     // (Self)Capture: initial, or inside a chain
  44     const initPiece = (piece || this.getPiece(sx, sy)),
  45           destPiece = this.getPiece(ex, ey);
  46     let mv = new Move({
  47       start: {x: sx, y: sy},
  48       end: {x: ex, y: ey},
  49       appear: [
  50         new PiPo({
  51           x: ex,
  52           y: ey,
  53           c: this.turn,
  54           p: (!!tr ? tr.p : initPiece)
  55         })
  56       ],
  57       vanish: [
  58         new PiPo({
  59           x: ex,
  60           y: ey,
  61           c: this.turn,
  62           p: destPiece
  63         })
  64       ]
  65     });
  66     if (!piece) {
  67       // Initial capture
  68       mv.vanish.unshift(
  69         new PiPo({
  70           x: sx,
  71           y: sy,
  72           c: this.turn,
  73           p: initPiece
  74         })
  75       );
  76     }
  77     mv.chained = destPiece; //easier (no need to detect it)
  78     return mv;
  79   }
  80
  81   getPiece(x, y) {
  82     const L = this.lastMoveEnd.length;
  83     if (L >= 1 && this.lastMoveEnd[L-1].x == x && this.lastMoveEnd[L-1].y == y)
  84       return this.lastMoveEnd[L-1].p;
  85     return super.getPiece(x, y);
  86   }
  87
  88   getPotentialMovesFrom([x, y], color) {
  89     const L = this.lastMoveEnd.length;
  90     if (
  91       L >= 1 &&
  92       (x != this.lastMoveEnd[L-1].x || y != this.lastMoveEnd[L-1].y)
  93     ) {
  94       // A self-capture was played: wrong square
  95       return [];
  96     }
  97     return super.getPotentialMovesFrom([x, y], color);
  98   }
  99
 100   isLastMove(move) {
 101     return !move.chained;
 102   }
 103
 104   postPlay(move) {
 105     super.postPlay(move);
 106     if (!!move.converted) {
 107       this.lastMoveEnd.push({
 108         x: move.end.x,
 109         y: move.end.y,
 110         p: move.chained
 111       });
 112     }
 113     else
 114       this.lastMoveEnd = [];
 115   }
 116
 117 };