client/src/variants/Arena.js

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