variants/Bicolour/class.js

   1 import ChessRules from "/base_rules.js";
   2 import {Random} from "/utils/alea.js";
   3 import {ArrayFun} from "/utils/array.js";
   4
   5 export class BicolourRules extends ChessRules {
   6
   7   // TODO: Options
   8
   9   get hasFlags() {
  10     return false;
  11   }
  12
  13   canTake([x1, y1], [x2, y2]) {
  14     return (this.getPiece(x2, y2) == 'k' || super.canTake([x1, y1], [x2, y2]));
  15   }
  16
  17   genRandInitBaseFen() {
  18     if (this.options["randomness"] == 0)
  19       return { fen: "rqbnkbnr/pppppppp/8/8/8/8/PPPPPPPP/RQBNKBNR", o: {} };
  20
  21     // Place pieces at random but the king cannot be next to a rook or queen.
  22     // => One bishop and one knight should surround the king.
  23     let pieces = {w: new Array(8), b: new Array(8)};
  24     let flags = "";
  25     for (let c of ["w", "b"]) {
  26       if (c == 'b' && this.options["randomness"] == 1) {
  27         pieces['b'] = pieces['w'];
  28         break;
  29       }
  30       let positions = ArrayFun.range(8);
  31       const kingPos = randInt(8);
  32       let toRemove = [kingPos];
  33       let knight1Pos = undefined;
  34       let bishop1Pos = undefined;
  35       if (kingPos == 0) {
  36         if (Random.randBool())
  37           knight1Pos = 1;
  38         else
  39           bishop1Pos = 1;
  40         toRemove.push(1);
  41       }
  42       else if (kingPos == V.size.y - 1) {
  43         if (Random.randBool())
  44           knight1Pos = V.size.y - 2;
  45         else
  46           bishop1Pos = V.size.y - 2;
  47         toRemove.push(V.size.y - 2);
  48       }
  49       else {
  50         knight1Pos = kingPos + (Random.randBool() ? 1 : -1);
  51         bishop1Pos = kingPos + (knight1Pos < kingPos ? 1 : -1);
  52         toRemove.push(knight1Pos, bishop1Pos);
  53       }
  54       const firstPieces = [kingPos, knight1Pos, bishop1Pos]
  55         .filter(elt => elt !== undefined);
  56       firstPieces
  57         .sort((a, b) => b - a)
  58         .forEach(elt => positions.splice(elt, 1));
  59       let randIndex = undefined;
  60       if (bishop1Pos === undefined) {
  61         const posWithIdx = positions.map((e,i) => { return {e: e, i: i}; });
  62         let availableSquares = posWithIdx.filter(p => p.e % 2 == 0);
  63         randIndex = randInt(availableSquares.length);
  64         bishop1Pos = availableSquares[randIndex].e;
  65         positions.splice(availableSquares[randIndex].i, 1);
  66       }
  67       const posWithIdx = positions.map((e,i) => { return {e: e, i: i}; });
  68       const rem1B = bishop1Pos % 2;
  69       let availableSquares = posWithIdx.filter(p => p.e % 2 == 1 - rem1B);
  70       randIndex = randInt(availableSquares.length);
  71       const bishop2Pos = availableSquares[randIndex].e;
  72       positions.splice(availableSquares[randIndex].i, 1);
  73       if (knight1Pos === undefined) {
  74         randIndex = randInt(5);
  75         knight1Pos = positions[randIndex];
  76         positions.splice(randIndex, 1);
  77       }
  78       randIndex = randInt(4);
  79       const knight2Pos = positions[randIndex];
  80       positions.splice(randIndex, 1);
  81       randIndex = randInt(3);
  82       const queenPos = positions[randIndex];
  83       positions.splice(randIndex, 1);
  84       const rook1Pos = positions[0];
  85       const rook2Pos = positions[1];
  86       pieces[c][rook1Pos] = "r";
  87       pieces[c][knight1Pos] = "n";
  88       pieces[c][bishop1Pos] = "b";
  89       pieces[c][queenPos] = "q";
  90       pieces[c][kingPos] = "k";
  91       pieces[c][bishop2Pos] = "b";
  92       pieces[c][knight2Pos] = "n";
  93       pieces[c][rook2Pos] = "r";
  94     }
  95
  96     return {
  97       fen: (
  98         pieces["b"].join("") +
  99         "/pppppppp/8/8/8/8/PPPPPPPP/" +
 100         pieces["w"].join("").toUpperCase()
 101       ),
 102       o: {}
 103     };
 104   }
 105
 106   underCheck(color) {
 107     const kingPos = this.searchKingPos(color)[0],
 108     return (this.underAttack(kingPos, 'w') || this.underAttack(kingPos, 'b'));
 109   }
 110
 111 };