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