client/src/variants/Atomic.js

   1 import { ChessRules, PiPo } from "@/base_rules";
   2
   3 export const VariantRules = class AtomicRules extends ChessRules {
   4   getEpSquare(moveOrSquare) {
   5     if (typeof moveOrSquare !== "object" || moveOrSquare.appear.length > 0)
   6       return super.getEpSquare(moveOrSquare);
   7     // Capturing move: no en-passant
   8     return undefined;
   9   }
  10
  11   getPotentialMovesFrom([x, y]) {
  12     let moves = super.getPotentialMovesFrom([x, y]);
  13
  14     // Handle explosions
  15     moves.forEach(m => {
  16       // NOTE: if vanish.length==2 and appear.length==2, this is castle
  17       if (m.vanish.length > 1 && m.appear.length <= 1) {
  18         // Explosion! (TODO?: drop moves which explode our king here)
  19         let steps = [
  20           [-1, -1],
  21           [-1, 0],
  22           [-1, 1],
  23           [0, -1],
  24           [0, 1],
  25           [1, -1],
  26           [1, 0],
  27           [1, 1]
  28         ];
  29         for (let step of steps) {
  30           let x = m.end.x + step[0];
  31           let y = m.end.y + step[1];
  32           if (
  33             V.OnBoard(x, y) &&
  34             this.board[x][y] != V.EMPTY &&
  35             this.getPiece(x, y) != V.PAWN
  36           ) {
  37             m.vanish.push(
  38               new PiPo({
  39                 p: this.getPiece(x, y),
  40                 c: this.getColor(x, y),
  41                 x: x,
  42                 y: y
  43               })
  44             );
  45           }
  46         }
  47         m.end = { x: m.appear[0].x, y: m.appear[0].y };
  48         m.appear.pop(); //Nothin appears in this case
  49       }
  50     });
  51
  52     return moves;
  53   }
  54
  55   getPotentialKingMoves([x, y]) {
  56     // King cannot capture:
  57     let moves = [];
  58     const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
  59     for (let step of steps) {
  60       const i = x + step[0];
  61       const j = y + step[1];
  62       if (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY)
  63         moves.push(this.getBasicMove([x, y], [i, j]));
  64     }
  65     return moves.concat(this.getCastleMoves([x, y]));
  66   }
  67
  68   isAttacked(sq, color) {
  69     if (
  70       this.getPiece(sq[0], sq[1]) == V.KING &&
  71       this.isAttackedByKing(sq, color)
  72     ) {
  73       // A king next to the enemy king is immune to attacks
  74       return false;
  75     }
  76     return (
  77       this.isAttackedByPawn(sq, color) ||
  78       this.isAttackedByRook(sq, color) ||
  79       this.isAttackedByKnight(sq, color) ||
  80       this.isAttackedByBishop(sq, color) ||
  81       this.isAttackedByQueen(sq, color)
  82       // No "attackedByKing": it cannot take
  83     );
  84   }
  85
  86   postPlay(move) {
  87     super.postPlay(move);
  88     if (move.appear.length == 0) {
  89       // Capture
  90       const firstRank = { w: 7, b: 0 };
  91       for (let c of ["w", "b"]) {
  92         // Did we explode king of color c ? (TODO: remove move earlier)
  93         if (
  94           Math.abs(this.kingPos[c][0] - move.end.x) <= 1 &&
  95           Math.abs(this.kingPos[c][1] - move.end.y) <= 1
  96         ) {
  97           this.kingPos[c] = [-1, -1];
  98           this.castleFlags[c] = [8, 8];
  99         } else {
 100           // Now check if init rook(s) exploded
 101           if (Math.abs(move.end.x - firstRank[c]) <= 1) {
 102             if (Math.abs(move.end.y - this.castleFlags[c][0]) <= 1)
 103               this.castleFlags[c][0] = 8;
 104             if (Math.abs(move.end.y - this.castleFlags[c][1]) <= 1)
 105               this.castleFlags[c][1] = 8;
 106           }
 107         }
 108       }
 109     }
 110   }
 111
 112   postUndo(move) {
 113     super.postUndo(move);
 114     const c = this.turn;
 115     const oppCol = V.GetOppCol(c);
 116     if ([this.kingPos[c][0], this.kingPos[oppCol][0]].some(e => e < 0)) {
 117       // There is a chance that last move blowed some king away..
 118       for (let psq of move.vanish) {
 119         if (psq.p == "k")
 120           this.kingPos[psq.c == c ? c : oppCol] = [psq.x, psq.y];
 121       }
 122     }
 123   }
 124
 125   underCheck(color) {
 126     const oppCol = V.GetOppCol(color);
 127     let res = undefined;
 128     // If our king disappeared, move is not valid
 129     if (this.kingPos[color][0] < 0) res = true;
 130     // If opponent king disappeared, move is valid
 131     else if (this.kingPos[oppCol][0] < 0) res = false;
 132     // Otherwise, if we remain under check, move is not valid
 133     else res = this.isAttacked(this.kingPos[color], oppCol);
 134     return res;
 135   }
 136
 137   getCheckSquares(color) {
 138     let res = [];
 139     if (
 140       this.kingPos[color][0] >= 0 && //king might have exploded
 141       this.isAttacked(this.kingPos[color], V.GetOppCol(color))
 142     ) {
 143       res = [JSON.parse(JSON.stringify(this.kingPos[color]))];
 144     }
 145     return res;
 146   }
 147
 148   getCurrentScore() {
 149     const color = this.turn;
 150     const kp = this.kingPos[color];
 151     if (kp[0] < 0)
 152       // King disappeared
 153       return color == "w" ? "0-1" : "1-0";
 154     if (this.atLeastOneMove())
 155       return "*";
 156     if (!this.isAttacked(kp, V.GetOppCol(color))) return "1/2";
 157     return color == "w" ? "0-1" : "1-0"; //checkmate
 158   }
 159 };