client/src/variants/Diamond.js

   1 import { ChessRules } from "@/base_rules";
   2 import { ArrayFun } from "@/utils/array";
   3 import { shuffle } from "@/utils/alea";
   4
   5 export class DiamondRules extends ChessRules {
   6
   7   static get HasFlags() {
   8     return false;
   9   }
  10
  11   static get HasEnpassant() {
  12     return false;
  13   }
  14
  15   static GenRandInitFen(randomness) {
  16     if (randomness == 0)
  17       return "krbp4/rqnp4/nbpp4/pppp4/4PPPP/4PPBN/4PNQR/4PBRK w 0";
  18     let pieces = { w: new Array(8), b: new Array(8) };
  19     for (let c of ["w", "b"]) {
  20       if (c == 'b' && randomness == 1) {
  21         pieces['b'] = pieces['w'];
  22         break;
  23       }
  24       // Get random squares for every piece, totally freely
  25       let positions = shuffle(ArrayFun.range(8));
  26       const composition = ['b', 'b', 'r', 'r', 'n', 'n', 'k', 'q'];
  27       const rem2 = positions[0] % 2;
  28       if (rem2 == positions[1] % 2) {
  29         // Fix bishops (on different colors)
  30         for (let i=2; i<8; i++) {
  31           if (positions[i] % 2 != rem2) {
  32             [positions[1], positions[i]] = [positions[i], positions[1]];
  33             break;
  34           }
  35         }
  36       }
  37       for (let i = 0; i < 8; i++) pieces[c][positions[i]] = composition[i];
  38     }
  39     return (
  40       pieces["b"].slice(0, 3).join("") + "p4/" +
  41       pieces["b"].slice(3, 6).join("") + "p4/" +
  42       pieces["b"].slice(6, 8).join("") + "pp4/" +
  43       "pppp4/4PPPP/" +
  44       "4PP" + pieces["w"].slice(6, 8).reverse().join("").toUpperCase() + "/" +
  45       "4P" + pieces["w"].slice(3, 6).reverse().join("").toUpperCase() + "/" +
  46       "4P" + pieces["w"].slice(0, 3).reverse().join("").toUpperCase() +
  47       " w 0"
  48     );
  49   }
  50
  51   // Special pawns movements
  52   getPotentialPawnMoves([x, y]) {
  53     const color = this.turn;
  54     let moves = [];
  55     const [sizeX, sizeY] = [V.size.x, V.size.y];
  56     const shift = (color == "w" ? -1 : 1);
  57     const lastRank = (color == "w" ? 0 : 7);
  58
  59     // One square forward (diagonally along h1-a8)
  60     if (this.board[x + shift][y + shift] == V.EMPTY) {
  61       const finalPieces =
  62         [x + shift, y + shift].includes(lastRank)
  63           ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN]
  64           : [V.PAWN];
  65       for (let piece of finalPieces) {
  66         moves.push(
  67           this.getBasicMove(
  68             [x, y], [x + shift, y + shift], { c: color, p: piece })
  69         );
  70       }
  71     }
  72     // Capture
  73     for (let pShift of [[0, shift], [shift, 0]]) {
  74       if (
  75         this.board[x + pShift[0]][y + pShift[1]] != V.EMPTY &&
  76         this.canTake([x, y], [x + pShift[0], y + pShift[1]])
  77       ) {
  78         const finalPieces =
  79           [x + pShift[0], y + pShift[1]].includes(lastRank)
  80             ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN]
  81             : [V.PAWN];
  82         for (let piece of finalPieces) {
  83           moves.push(
  84             this.getBasicMove(
  85               [x, y],
  86               [x + pShift[0], y + pShift[1]],
  87               {
  88                 c: color,
  89                 p: piece
  90               }
  91             )
  92           );
  93         }
  94       }
  95     }
  96
  97     return moves;
  98   }
  99
 100   isAttackedByPawn([x, y], color) {
 101     let pawnShift = (color == "w" ? 1 : -1);
 102     return (
 103       (
 104         x + pawnShift >= 0 && x + pawnShift < V.size.x &&
 105         this.getPiece(x + pawnShift, y) == V.PAWN &&
 106         this.getColor(x + pawnShift, y) == color
 107       )
 108       ||
 109       (
 110         y + pawnShift >= 0 && y + pawnShift < V.size.y &&
 111         this.getPiece(x, y + pawnShift) == V.PAWN &&
 112         this.getColor(x, y + pawnShift) == color
 113       )
 114     );
 115   }
 116
 117   static get SEARCH_DEPTH() {
 118     return 2;
 119   }
 120
 121   getNotation(move) {
 122     const piece = this.getPiece(move.start.x, move.start.y);
 123     if (piece == V.PAWN) {
 124       // Pawn move
 125       const finalSquare = V.CoordsToSquare(move.end);
 126       let notation = "";
 127       if (move.vanish.length == 2)
 128         // Capture
 129         notation = "Px" + finalSquare;
 130       else {
 131         // No capture: indicate the initial square for potential ambiguity
 132         const startSquare = V.CoordsToSquare(move.start);
 133         notation = startSquare + finalSquare;
 134       }
 135       if (move.appear[0].p != V.PAWN)
 136         // Promotion
 137         notation += "=" + move.appear[0].p.toUpperCase();
 138       return notation;
 139     }
 140     return super.getNotation(move); //all other pieces are orthodox
 141   }
 142
 143 };