variants/Circular/class.js

   1 import ChessRules from "/base_rules.js";
   2 import {FenUtil} from "/utils/setupPieces.js";
   3
   4 export default class CircularRules extends ChessRules {
   5
   6   get hasCastle() {
   7     return false;
   8   }
   9   get hasEnpassant() {
  10     return false;
  11   }
  12
  13   // Everypawn is going up!
  14   getPawnShift(color) {
  15     return -1;
  16   }
  17   isPawnInitRank(x, color) {
  18     return (color == 'w' && x == 6) || (color == 'b' && x == 2);
  19   }
  20
  21   get flippedBoard() {
  22     return false;
  23   }
  24
  25   // Circular board:
  26   // TODO: graph with segments, as for cylindrical...
  27   getX(x) {
  28     let res = x % this.size.x;
  29     if (res < 0)
  30       res += this.size.x;
  31     return res;
  32   }
  33
  34   // TODO: rewrite in more elegant way
  35   getFlagsFen() {
  36     let flags = "";
  37     for (let c of ["w", "b"]) {
  38       for (let i = 0; i < 8; i++)
  39         flags += this.pawnFlags[c][i] ? "1" : "0";
  40     }
  41     return flags;
  42   }
  43
  44   setFlags(fenflags) {
  45     this.pawnFlags = {
  46       w: [...Array(8)], //pawns can move 2 squares?
  47       b: [...Array(8)]
  48     };
  49     for (let c of ["w", "b"]) {
  50       for (let i = 0; i < 8; i++)
  51         this.pawnFlags[c][i] = fenflags.charAt((c == "w" ? 0 : 8) + i) == "1";
  52     }
  53   }
  54
  55   genRandInitBaseFen() {
  56     let setupOpts = {
  57       randomness: this.options["randomness"],
  58       diffCol: ['b']
  59     };
  60     const s = FenUtil.setupPieces(
  61       ['r', 'n', 'b', 'q', 'k', 'b', 'n', 'r'], setupOpts);
  62     return {
  63       fen: "8/8/pppppppp/" + s.b.join("") + "/8/8/PPPPPPPP/" +
  64            s.w.join("").toUpperCase(),
  65       o: {flags: "11111111"}
  66     };
  67   }
  68
  69   filterValid(moves) {
  70     const filteredMoves = super.filterValid(moves);
  71     // If at least one full move made, everything is allowed:
  72     if (this.movesCount >= 2)
  73       return filteredMoves;
  74     // Else, forbid checks:
  75     const oppCol = C.GetOppTurn(this.turn);
  76     const oppKingPos = this.searchKingPos(oppCol);
  77     return filteredMoves.filter(m => {
  78       this.playOnBoard(m);
  79       const res = !this.underCheck(oppKingPos, [this.turn]);
  80       this.undoOnBoard(m);
  81       return res;
  82     });
  83   }
  84
  85   prePlay(move) {
  86     if (move.appear.length > 0 && move.vanish.length > 0) {
  87       super.prePlay(move);
  88       if (
  89         [2, 6].includes(move.start.x) &&
  90         move.vanish[0].p == 'p' &&
  91         Math.abs(move.end.x - move.start.x) == 2
  92       ) {
  93         // This move turns off a 2-squares pawn flag
  94         this.pawnFlags[move.start.x == 6 ? "w" : "b"][move.start.y] = false;
  95       }
  96     }
  97   }
  98
  99 };