client/src/variants/Atomic.js

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