client/src/variants/Bicolour.js

   1 import { ChessRules } from "@/base_rules";
   2 import { randInt } from "@/utils/alea";
   3 import { ArrayFun } from "@/utils/array";
   4
   5 export class BicolourRules extends ChessRules {
   6
   7   static get HasFlags() {
   8     return false;
   9   }
  10
  11   canTake([x1, y1], [x2, y2]) {
  12     return (
  13       this.getPiece(x1, y1) == V.KING || super.canTake([x1, y1], [x2, y2])
  14     );
  15   }
  16
  17   static GenRandInitFen(options) {
  18     if (options.randomness == 0)
  19       return "rqbnkbnr/pppppppp/8/8/8/8/PPPPPPPP/RQBNKBNR w 0 -";
  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' && options.randomness == 1) {
  27         pieces['b'] = pieces['w'];
  28         break;
  29       }
  30
  31       let positions = ArrayFun.range(8);
  32
  33       const kingPos = randInt(8);
  34       let toRemove = [kingPos];
  35       let knight1Pos = undefined;
  36       let bishop1Pos = undefined;
  37       if (kingPos == 0) {
  38         if (Math.random() < 0.5) knight1Pos = 1;
  39         else bishop1Pos = 1;
  40         toRemove.push(1);
  41       }
  42       else if (kingPos == V.size.y - 1) {
  43         if (Math.random() < 0.5) knight1Pos = V.size.y - 2;
  44         else bishop1Pos = V.size.y - 2;
  45         toRemove.push(V.size.y - 2);
  46       }
  47       else {
  48         knight1Pos = kingPos + (Math.random() < 0.5 ? 1 : -1);
  49         bishop1Pos = kingPos + (knight1Pos < kingPos ? 1 : -1);
  50         toRemove.push(knight1Pos, bishop1Pos);
  51       }
  52       const firstPieces = [kingPos, knight1Pos, bishop1Pos]
  53         .filter(elt => elt !== undefined);
  54       firstPieces
  55         .sort((a, b) => b - a)
  56         .forEach(elt => positions.splice(elt, 1));
  57
  58       let randIndex = undefined;
  59       if (bishop1Pos === undefined) {
  60         const posWithIdx = positions.map((e,i) => { return { e: e, i: i }; });
  61         let availableSquares = posWithIdx.filter(p => p.e % 2 == 0);
  62         randIndex = randInt(availableSquares.length);
  63         bishop1Pos = availableSquares[randIndex].e;
  64         positions.splice(availableSquares[randIndex].i, 1);
  65       }
  66       const posWithIdx = positions.map((e,i) => { return { e: e, i: i }; });
  67       const rem1B = bishop1Pos % 2;
  68       let availableSquares = posWithIdx.filter(p => p.e % 2 == 1 - rem1B);
  69       randIndex = randInt(availableSquares.length);
  70       const bishop2Pos = availableSquares[randIndex].e;
  71       positions.splice(availableSquares[randIndex].i, 1);
  72
  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
  82       randIndex = randInt(3);
  83       const queenPos = positions[randIndex];
  84       positions.splice(randIndex, 1);
  85
  86       const rook1Pos = positions[0];
  87       const rook2Pos = positions[1];
  88
  89       pieces[c][rook1Pos] = "r";
  90       pieces[c][knight1Pos] = "n";
  91       pieces[c][bishop1Pos] = "b";
  92       pieces[c][queenPos] = "q";
  93       pieces[c][kingPos] = "k";
  94       pieces[c][bishop2Pos] = "b";
  95       pieces[c][knight2Pos] = "n";
  96       pieces[c][rook2Pos] = "r";
  97     }
  98     return (
  99       pieces["b"].join("") +
 100       "/pppppppp/8/8/8/8/PPPPPPPP/" +
 101       pieces["w"].join("").toUpperCase() +
 102       " w 0 -"
 103     );
 104   }
 105
 106   underCheck(color) {
 107     return (
 108       this.isAttacked(this.kingPos[color], 'w') ||
 109       this.isAttacked(this.kingPos[color], 'b')
 110     );
 111   }
 112
 113 };