client/src/variants/Isardam.js

   1 import { ChessRules } from "@/base_rules";
   2
   3 export class IsardamRules extends ChessRules {
   4
   5   isImmobilized(sq) {
   6     const oppCol = V.GetOppCol(this.getColor(sq[0], sq[1]));
   7     const piece = this.getPiece(sq[0], sq[1]);
   8     let steps = [];
   9     switch (piece) {
  10       // NOTE: cannot use super.isAttackedByXXX
  11       // because it would call the redefined isAttackedBySlideNJump
  12       // => Infinite recursive calls.
  13       case V.PAWN: {
  14         const forward = (oppCol == 'w' ? 1 : -1);
  15         steps = [[forward, 1], [forward, -1]];
  16         break;
  17       }
  18       case V.ROOK:
  19       case V.BISHOP:
  20       case V.KNIGHT:
  21         steps = V.steps[piece];
  22         break;
  23       case V.KING:
  24       case V.QUEEN:
  25         steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
  26         break;
  27     }
  28     return super.isAttackedBySlideNJump(
  29       sq, oppCol, piece, steps, [V.KING, V.PAWN, V.KNIGHT].includes(piece))
  30   }
  31
  32   getPotentialMovesFrom([x, y]) {
  33     return (
  34       super.getPotentialMovesFrom([x, y]).filter(m => {
  35         let res = true;
  36         this.play(m);
  37         if (this.isImmobilized([m.end.x, m.end.y])) res = false;
  38         else {
  39           // Check discovered attacks
  40           for (let step of V.steps[V.BISHOP].concat(V.steps[V.ROOK])) {
  41             let allowedPieces = [V.QUEEN];
  42             if (step[0] == 0 || step[1] == 0) allowedPieces.push(V.ROOK);
  43             else allowedPieces.push(V.BISHOP);
  44             let [i, j] = [m.start.x + step[0], m.start.y + step[1]];
  45             while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
  46               i += step[0];
  47               j += step[1];
  48             }
  49             if (V.OnBoard(i, j)) {
  50               const meet = { c: this.getColor(i, j), p: this.getPiece(i, j) };
  51               if (allowedPieces.includes(meet.p)) {
  52                 // Search in the other direction
  53                 [i, j] = [m.start.x - step[0], m.start.y - step[1]];
  54                 while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
  55                   i -= step[0];
  56                   j -= step[1];
  57                 }
  58                 if (
  59                   V.OnBoard(i, j) &&
  60                   this.getPiece(i, j) == meet.p &&
  61                   this.getColor(i, j) != meet.c
  62                 ) {
  63                   res = false;
  64                   break;
  65                 }
  66               }
  67             }
  68           }
  69         }
  70         this.undo(m);
  71         return res;
  72       })
  73     );
  74   }
  75
  76 };