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, colors) {
  69     if (
  70       this.getPiece(sq[0], sq[1]) == V.KING &&
  71       this.isAttackedByKing(sq, colors)
  72     )
  73       return false; //king cannot take...
  74     return (
  75       this.isAttackedByPawn(sq, colors) ||
  76       this.isAttackedByRook(sq, colors) ||
  77       this.isAttackedByKnight(sq, colors) ||
  78       this.isAttackedByBishop(sq, colors) ||
  79       this.isAttackedByQueen(sq, colors)
  80     );
  81   }
  82
  83   postPlay(move) {
  84     super.postPlay(move);
  85     if (move.appear.length == 0) {
  86       // Capture
  87       const firstRank = { w: 7, b: 0 };
  88       for (let c of ["w", "b"]) {
  89         // Did we explode king of color c ? (TODO: remove move earlier)
  90         if (
  91           Math.abs(this.kingPos[c][0] - move.end.x) <= 1 &&
  92           Math.abs(this.kingPos[c][1] - move.end.y) <= 1
  93         ) {
  94           this.kingPos[c] = [-1, -1];
  95           this.castleFlags[c] = [8, 8];
  96         } else {
  97           // Now check if init rook(s) exploded
  98           if (Math.abs(move.end.x - firstRank[c]) <= 1) {
  99             if (Math.abs(move.end.y - this.castleFlags[c][0]) <= 1)
 100               this.castleFlags[c][0] = 8;
 101             if (Math.abs(move.end.y - this.castleFlags[c][1]) <= 1)
 102               this.castleFlags[c][1] = 8;
 103           }
 104         }
 105       }
 106     }
 107   }
 108
 109   postUndo(move) {
 110     super.postUndo(move);
 111     const c = this.turn;
 112     const oppCol = V.GetOppCol(c);
 113     if ([this.kingPos[c][0], this.kingPos[oppCol][0]].some(e => e < 0)) {
 114       // There is a chance that last move blowed some king away..
 115       for (let psq of move.vanish) {
 116         if (psq.p == "k")
 117           this.kingPos[psq.c == c ? c : oppCol] = [psq.x, psq.y];
 118       }
 119     }
 120   }
 121
 122   underCheck(color) {
 123     const oppCol = V.GetOppCol(color);
 124     let res = undefined;
 125     // If our king disappeared, move is not valid
 126     if (this.kingPos[color][0] < 0) res = true;
 127     // If opponent king disappeared, move is valid
 128     else if (this.kingPos[oppCol][0] < 0) res = false;
 129     // Otherwise, if we remain under check, move is not valid
 130     else res = this.isAttacked(this.kingPos[color], [oppCol]);
 131     return res;
 132   }
 133
 134   getCheckSquares(color) {
 135     let res = [];
 136     if (
 137       this.kingPos[color][0] >= 0 && //king might have exploded
 138       this.isAttacked(this.kingPos[color], [V.GetOppCol(color)])
 139     ) {
 140       res = [JSON.parse(JSON.stringify(this.kingPos[color]))];
 141     }
 142     return res;
 143   }
 144
 145   getCurrentScore() {
 146     const color = this.turn;
 147     const kp = this.kingPos[color];
 148     if (kp[0] < 0)
 149       // King disappeared
 150       return color == "w" ? "0-1" : "1-0";
 151     if (this.atLeastOneMove())
 152       return "*";
 153     if (!this.isAttacked(kp, [V.GetOppCol(color)])) return "1/2";
 154     return color == "w" ? "0-1" : "1-0"; //checkmate
 155   }
 156 };