client/src/variants/Arena.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 export class ArenaRules extends ChessRules {
   4   static get HasFlags() {
   5     return false;
   6   }
   7
   8   static get PawnSpecs() {
   9     return Object.assign(
  10       {},
  11       ChessRules.PawnSpecs,
  12       { captureBackward: true }
  13     );
  14   }
  15
  16   static IsGoodPosition(position) {
  17     if (position.length == 0) return false;
  18     const rows = position.split("/");
  19     if (rows.length != V.size.x) return false;
  20     // At most and at least one king or queen per color
  21     let royals = { "k": 0, "K": 0, "q": 0, "Q": 0 };
  22     for (let row of rows) {
  23       let sumElts = 0;
  24       for (let i = 0; i < row.length; i++) {
  25         if (['K','k','Q','q'].includes(row[i])) royals[row[i]]++;
  26         if (V.PIECES.includes(row[i].toLowerCase())) sumElts++;
  27         else {
  28           const num = parseInt(row[i]);
  29           if (isNaN(num)) return false;
  30           sumElts += num;
  31         }
  32       }
  33       if (sumElts != V.size.y) return false;
  34     }
  35     if (
  36       Object.values(royals).some(v => v >= 2) ||
  37       royals['K'] + royals['Q'] == 0 ||
  38       royals['k'] + royals['q'] == 0
  39     ) {
  40       return false;
  41     }
  42     return true;
  43   }
  44
  45   scanKings() {}
  46
  47   static GenRandInitFen(randomness) {
  48     return ChessRules.GenRandInitFen(randomness).slice(0, -6) + "-";
  49   }
  50
  51   static InArena(x) {
  52     return Math.abs(3.5 - x) <= 1.5;
  53   }
  54
  55   getPotentialMovesFrom([x, y]) {
  56     const moves = super.getPotentialMovesFrom([x, y]);
  57     // Eliminate moves which neither enter the arena or capture something
  58     return moves.filter(m => {
  59       const startInArena = V.InArena(m.start.x);
  60       const endInArena = V.InArena(m.end.x);
  61       return (
  62         (startInArena && endInArena && m.vanish.length == 2) ||
  63         (!startInArena && endInArena)
  64       );
  65     });
  66
  67     return moves;
  68   }
  69
  70   getPotentialQueenMoves(sq) {
  71     return this.getSlideNJumpMoves(
  72       sq,
  73       V.steps[V.ROOK].concat(V.steps[V.BISHOP])
  74     ).filter(m => {
  75       // Filter out moves longer than 3 squares
  76       return Math.max(
  77         Math.abs(m.end.x - m.start.x),
  78         Math.abs(m.end.y - m.start.y)) <= 3;
  79     });
  80   }
  81
  82   getPotentialKingMoves(sq) {
  83     return this.getSlideNJumpMoves(
  84       sq,
  85       V.steps[V.ROOK].concat(V.steps[V.BISHOP])
  86     ).filter(m => {
  87       // Filter out moves longer than 3 squares
  88       return Math.max(
  89         Math.abs(m.end.x - m.start.x),
  90         Math.abs(m.end.y - m.start.y)) <= 3;
  91     });
  92   }
  93
  94   getCheckSquares() {
  95     return [];
  96   }
  97
  98   filterValid(moves) {
  99     // No check conditions
 100     return moves;
 101   }
 102
 103   getCurrentScore() {
 104     const color = this.turn;
 105     if (!this.atLeastOneMove())
 106       // I cannot move anymore
 107       return color == "w" ? "0-1" : "1-0";
 108     // Win if the opponent has no more pieces left (in the Arena),
 109     // (and/)or if he lost both his dukes.
 110     let someUnitRemain = false;
 111     let atLeastOneDuke = false;
 112     let somethingInArena = false;
 113     outerLoop: for (let i=0; i<V.size.x; i++) {
 114       for (let j=0; j<V.size.y; j++) {
 115         if (this.getColor(i,j) == color) {
 116           someUnitRemain = true;
 117           if (this.movesCount >= 2 && V.InArena(i)) {
 118             somethingInArena = true;
 119             if (atLeastOneDuke)
 120               break outerLoop;
 121           }
 122           if ([V.QUEEN,V.KING].includes(this.getPiece(i,j))) {
 123             atLeastOneDuke = true;
 124             if (this.movesCount < 2 || somethingInArena)
 125               break outerLoop;
 126           }
 127         }
 128       }
 129     }
 130     if (
 131       !someUnitRemain ||
 132       !atLeastOneDuke ||
 133       (this.movesCount >= 2 && !somethingInArena)
 134     ) {
 135       return color == "w" ? "0-1" : "1-0";
 136     }
 137     return "*";
 138   }
 139
 140   static get SEARCH_DEPTH() {
 141     return 4;
 142   }
 143 };