client/src/variants/Suicide.js

   1 import { ChessRules } from "@/base_rules";
   2 import { ArrayFun } from "@/utils/array";
   3 import { shuffle } from "@/utils/alea";
   4
   5 export class SuicideRules extends ChessRules {
   6
   7   static get HasFlags() {
   8     return false;
   9   }
  10
  11   static get PawnSpecs() {
  12     return Object.assign(
  13       {},
  14       ChessRules.PawnSpecs,
  15       { promotions: ChessRules.PawnSpecs.promotions.concat([V.KING]) }
  16     );
  17   }
  18
  19   static IsGoodPosition(position) {
  20     if (position.length == 0) return false;
  21     const rows = position.split("/");
  22     if (rows.length != V.size.x) return false;
  23     // Just check that at least one piece of each color is there:
  24     let pieces = { "w": 0, "b": 0 };
  25     for (let row of rows) {
  26       let sumElts = 0;
  27       for (let i = 0; i < row.length; i++) {
  28         const lowerRi = row[i].toLowerCase();
  29         if (V.PIECES.includes(lowerRi)) {
  30           pieces[row[i] == lowerRi ? "b" : "w"]++;
  31           sumElts++;
  32         }
  33         else {
  34           const num = parseInt(row[i], 10);
  35           if (isNaN(num)) return false;
  36           sumElts += num;
  37         }
  38       }
  39       if (sumElts != V.size.y) return false;
  40     }
  41     if (Object.values(pieces).some(v => v == 0)) return false;
  42     return true;
  43   }
  44
  45   scanKings() {}
  46
  47   // Trim all non-capturing moves (not the most efficient, but easy)
  48   static KeepCaptures(moves) {
  49     return moves.filter(m => m.vanish.length == 2);
  50   }
  51
  52   // Stop at the first capture found (if any)
  53   atLeastOneCapture() {
  54     const color = this.turn;
  55     for (let i = 0; i < V.size.x; i++) {
  56       for (let j = 0; j < V.size.y; j++) {
  57         if (
  58           this.board[i][j] != V.EMPTY &&
  59           this.getColor(i, j) == color &&
  60           this.getPotentialMovesFrom([i, j]).some(m => m.vanish.length == 2)
  61         ) {
  62           return true;
  63         }
  64       }
  65     }
  66     return false;
  67   }
  68
  69   getPossibleMovesFrom(sq) {
  70     let moves = this.getPotentialMovesFrom(sq);
  71     const captureMoves = V.KeepCaptures(moves);
  72     if (captureMoves.length > 0) return captureMoves;
  73     if (this.atLeastOneCapture()) return [];
  74     return moves;
  75   }
  76
  77   filterValid(moves) {
  78     return moves;
  79   }
  80
  81   getAllValidMoves() {
  82     const moves = super.getAllValidMoves();
  83     if (moves.some(m => m.vanish.length == 2)) return V.KeepCaptures(moves);
  84     return moves;
  85   }
  86
  87   atLeastOneMove() {
  88     const color = this.turn;
  89     for (let i = 0; i < V.size.x; i++) {
  90       for (let j = 0; j < V.size.y; j++) {
  91         if (
  92           this.getColor(i, j) == color &&
  93           this.getPotentialMovesFrom([i, j]).length > 0
  94         ) {
  95           return true;
  96         }
  97       }
  98     }
  99     return false;
 100   }
 101
 102   getCheckSquares() {
 103     return [];
 104   }
 105
 106   // No variables update because no royal king + no castling
 107   prePlay() {}
 108   postPlay() {}
 109   preUndo() {}
 110   postUndo() {}
 111
 112   getCurrentScore() {
 113     if (this.atLeastOneMove()) return "*";
 114     // No valid move: the side who cannot move wins
 115     return this.turn == "w" ? "1-0" : "0-1";
 116   }
 117
 118   static get VALUES() {
 119     return {
 120       p: 1,
 121       r: 7,
 122       n: 3,
 123       b: 3,
 124       q: 5,
 125       k: 5
 126     };
 127   }
 128
 129   static get SEARCH_DEPTH() {
 130     return 4;
 131   }
 132
 133   evalPosition() {
 134     // Less material is better:
 135     return -super.evalPosition();
 136   }
 137
 138   static GenRandInitFen(randomness) {
 139     if (randomness == 0)
 140       return "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w 0 -";
 141
 142     let pieces = { w: new Array(8), b: new Array(8) };
 143     for (let c of ["w", "b"]) {
 144       if (c == 'b' && randomness == 1) {
 145         pieces['b'] = pieces['w'];
 146         break;
 147       }
 148
 149       // Get random squares for every piece, totally freely
 150       let positions = shuffle(ArrayFun.range(8));
 151       const composition = ['b', 'b', 'r', 'r', 'n', 'n', 'k', 'q'];
 152       const rem2 = positions[0] % 2;
 153       if (rem2 == positions[1] % 2) {
 154         // Fix bishops (on different colors)
 155         for (let i=2; i<8; i++) {
 156           if (positions[i] % 2 != rem2) {
 157             [positions[1], positions[i]] = [positions[i], positions[1]];
 158             break;
 159           }
 160         }
 161       }
 162       for (let i = 0; i < 8; i++) pieces[c][positions[i]] = composition[i];
 163     }
 164     return (
 165       pieces["b"].join("") +
 166       "/pppppppp/8/8/8/8/PPPPPPPP/" +
 167       pieces["w"].join("").toUpperCase() +
 168       // En-passant allowed, but no flags
 169       " w 0 -"
 170     );
 171   }
 172
 173 };