client/src/variants/Atomic1.js

   1 import { ChessRules, PiPo } from "@/base_rules";
   2
   3 export class Atomic1Rules extends ChessRules {
   4
   5   getPotentialMovesFrom([x, y]) {
   6     let moves = super.getPotentialMovesFrom([x, y]);
   7
   8     if (this.getPiece(x, y) == V.PAWN) {
   9       // Promotions by captures can be reduced to only one deterministic
  10       // move (because of the explosion).
  11       moves = moves.filter(m => {
  12         return (
  13           m.vanish.length == 1 ||
  14           [V.PAWN, V.QUEEN].includes(m.appear[0].p)
  15         );
  16       });
  17     }
  18
  19     // Handle explosions
  20     moves.forEach(m => {
  21       // NOTE: if vanish.length==2 and appear.length==2, this is castle
  22       if (m.vanish.length > 1 && m.appear.length <= 1) {
  23         // Explosion! (TODO?: drop moves which explode our king here)
  24         let steps = [
  25           [-1, -1],
  26           [-1, 0],
  27           [-1, 1],
  28           [0, -1],
  29           [0, 1],
  30           [1, -1],
  31           [1, 0],
  32           [1, 1]
  33         ];
  34         for (let step of steps) {
  35           let x = m.end.x + step[0];
  36           let y = m.end.y + step[1];
  37           if (
  38             V.OnBoard(x, y) &&
  39             this.board[x][y] != V.EMPTY &&
  40             this.getPiece(x, y) != V.PAWN
  41           ) {
  42             m.vanish.push(
  43               new PiPo({
  44                 p: this.getPiece(x, y),
  45                 c: this.getColor(x, y),
  46                 x: x,
  47                 y: y
  48               })
  49             );
  50           }
  51         }
  52         m.end = { x: m.appear[0].x, y: m.appear[0].y };
  53         m.appear.pop(); //Nothin appears in this case
  54       }
  55     });
  56
  57     return moves;
  58   }
  59
  60   getPotentialKingMoves([x, y]) {
  61     // King cannot capture:
  62     let moves = [];
  63     const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
  64     for (let step of steps) {
  65       const i = x + step[0];
  66       const j = y + step[1];
  67       if (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY)
  68         moves.push(this.getBasicMove([x, y], [i, j]));
  69     }
  70     return moves.concat(this.getCastleMoves([x, y]));
  71   }
  72
  73   isAttacked(sq, color) {
  74     if (
  75       this.getPiece(sq[0], sq[1]) == V.KING &&
  76       this.isAttackedByKing(sq, color)
  77     ) {
  78       // A king next to the enemy king is immune to attacks
  79       return false;
  80     }
  81     return (
  82       this.isAttackedByPawn(sq, color) ||
  83       this.isAttackedByRook(sq, color) ||
  84       this.isAttackedByKnight(sq, color) ||
  85       this.isAttackedByBishop(sq, color) ||
  86       this.isAttackedByQueen(sq, color)
  87       // No "attackedByKing": it cannot take
  88     );
  89   }
  90
  91   postPlay(move) {
  92     super.postPlay(move);
  93     // NOTE: (harmless) condition on movesCount for Atomic2
  94     if (move.appear.length == 0 && this.movesCount >= 2) {
  95       // Capture
  96       const firstRank = { w: 7, b: 0 };
  97       for (let c of ["w", "b"]) {
  98         // Did we explode king of color c ? (TODO: remove move earlier)
  99         if (
 100           Math.abs(this.kingPos[c][0] - move.end.x) <= 1 &&
 101           Math.abs(this.kingPos[c][1] - move.end.y) <= 1
 102         ) {
 103           this.kingPos[c] = [-1, -1];
 104           this.castleFlags[c] = [8, 8];
 105         }
 106         else {
 107           // Now check if init rook(s) exploded
 108           if (Math.abs(move.end.x - firstRank[c]) <= 1) {
 109             if (Math.abs(move.end.y - this.castleFlags[c][0]) <= 1)
 110               this.castleFlags[c][0] = 8;
 111             if (Math.abs(move.end.y - this.castleFlags[c][1]) <= 1)
 112               this.castleFlags[c][1] = 8;
 113           }
 114         }
 115       }
 116     }
 117   }
 118
 119   postUndo(move) {
 120     super.postUndo(move);
 121     const c = this.turn;
 122     const oppCol = V.GetOppCol(c);
 123     // NOTE: condition on movesCount for Atomic2
 124     if (
 125       this.movesCount >= 1 &&
 126       [this.kingPos[c][0], this.kingPos[oppCol][0]].some(e => e < 0)
 127     ) {
 128       // There is a chance that last move blowed some king away..
 129       for (let psq of move.vanish) {
 130         if (psq.p == "k")
 131           this.kingPos[psq.c == c ? c : oppCol] = [psq.x, psq.y];
 132       }
 133     }
 134   }
 135
 136   underCheck(color) {
 137     const oppCol = V.GetOppCol(color);
 138     let res = undefined;
 139     // If our king disappeared, move is not valid
 140     if (this.kingPos[color][0] < 0) res = true;
 141     // If opponent king disappeared, move is valid
 142     else if (this.kingPos[oppCol][0] < 0) res = false;
 143     // Otherwise, if we remain under check, move is not valid
 144     else res = this.isAttacked(this.kingPos[color], oppCol);
 145     return res;
 146   }
 147
 148   getCheckSquares() {
 149     const color = this.turn;
 150     let res = [];
 151     if (
 152       this.kingPos[color][0] >= 0 && //king might have exploded
 153       this.isAttacked(this.kingPos[color], V.GetOppCol(color))
 154     ) {
 155       res = [JSON.parse(JSON.stringify(this.kingPos[color]))];
 156     }
 157     return res;
 158   }
 159
 160   getCurrentScore() {
 161     const color = this.turn;
 162     const kp = this.kingPos[color];
 163     if (kp[0] < 0)
 164       // King disappeared
 165       return color == "w" ? "0-1" : "1-0";
 166     if (this.atLeastOneMove()) return "*";
 167     if (!this.isAttacked(kp, V.GetOppCol(color))) return "1/2";
 168     return color == "w" ? "0-1" : "1-0"; //checkmate
 169   }
 170
 171 };