client/src/variants/Benedict.js

   1 import { ChessRules, PiPo, Move } from "@/base_rules";
   2
   3 export class BenedictRules extends ChessRules {
   4   static get HasEnpassant() {
   5     return false;
   6   }
   7
   8   static get PawnSpecs() {
   9     return Object.assign(
  10       {},
  11       ChessRules.PawnSpecs,
  12       { canCapture: false }
  13     );
  14   }
  15
  16   // TODO(?): some duplicated code in 2 next functions
  17   getSlideNJumpMoves([x, y], steps, oneStep) {
  18     let moves = [];
  19     outerLoop: for (let loop = 0; loop < steps.length; loop++) {
  20       const step = steps[loop];
  21       let i = x + step[0];
  22       let j = y + step[1];
  23       while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
  24         moves.push(this.getBasicMove([x, y], [i, j]));
  25         if (oneStep) continue outerLoop;
  26         i += step[0];
  27         j += step[1];
  28       }
  29       // No capture check: handled elsewhere (next method)
  30     }
  31     return moves;
  32   }
  33
  34   // Find possible captures from a square
  35   // follow steps from x,y until something is met.
  36   findCaptures([x, y]) {
  37     const color = this.getColor(x, y);
  38     const piece = this.getPiece(x, y);
  39     let squares = [];
  40     const steps =
  41       piece != V.PAWN
  42         ? [V.QUEEN,V.KING].includes(piece)
  43           ? V.steps[V.ROOK].concat(V.steps[V.BISHOP])
  44           : V.steps[piece]
  45         : color == "w"
  46           ? [
  47             [-1, -1],
  48             [-1, 1]
  49           ]
  50           : [
  51             [1, -1],
  52             [1, 1]
  53           ];
  54     const oneStep = [V.KNIGHT,V.PAWN,V.KING].includes(piece);
  55     outerLoop: for (let loop = 0; loop < steps.length; loop++) {
  56       const step = steps[loop];
  57       let i = x + step[0];
  58       let j = y + step[1];
  59       while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
  60         if (oneStep) continue outerLoop;
  61         i += step[0];
  62         j += step[1];
  63       }
  64       if (
  65         V.OnBoard(i, j) &&
  66         this.getColor(i, j) == V.GetOppCol(color)
  67       ) {
  68         // eat!
  69         squares.push([i, j]);
  70       }
  71     }
  72     return squares;
  73   }
  74
  75   // TODO: appear/vanish description of a move is too verbose for Benedict.
  76   // => Would need a new "flipped" array, to be passed in Game.vue...
  77   getPotentialMovesFrom([x, y]) {
  78     const color = this.turn;
  79     const oppCol = V.GetOppCol(color);
  80     // Get all moves from x,y without captures:
  81     let moves = super.getPotentialMovesFrom([x, y]);
  82     // Add flips:
  83     moves.forEach(m => {
  84       let newAppear = [];
  85       let newVanish = [];
  86       V.PlayOnBoard(this.board, m);
  87       // If castling, m.appear has 2 elements.
  88       // In this case, consider the attacks of moving units only.
  89       // (Sometimes the king or rook doesn't move).
  90       for (let i = 0; i < m.appear.length; i++) {
  91         const a  = m.appear[i];
  92         if (m.vanish[i].x != a.x || m.vanish[i].y != a.y) {
  93           const flipped = this.findCaptures([a.x, a.y]);
  94           flipped.forEach(sq => {
  95             const piece = this.getPiece(sq[0],sq[1]);
  96             const pipoA = new PiPo({
  97               x:sq[0],
  98               y:sq[1],
  99               c:color,
 100               p:piece
 101             });
 102             const pipoV = new PiPo({
 103               x:sq[0],
 104               y:sq[1],
 105               c:oppCol,
 106               p:piece
 107             });
 108             newAppear.push(pipoA);
 109             newVanish.push(pipoV);
 110           });
 111         }
 112       }
 113       Array.prototype.push.apply(m.appear, newAppear);
 114       Array.prototype.push.apply(m.vanish, newVanish);
 115       V.UndoOnBoard(this.board, m);
 116     });
 117     return moves;
 118   }
 119
 120   // Moves cannot flip our king's color, so all are valid
 121   filterValid(moves) {
 122     return moves;
 123   }
 124
 125   // Since it's used just for the king, and there are no captures:
 126   isAttacked(sq, color) {
 127     return false;
 128   }
 129
 130   // No notion of check here:
 131   getCheckSquares() {
 132     return [];
 133   }
 134
 135   // Stop at the first move found
 136   atLeastOneMove() {
 137     const color = this.turn;
 138     for (let i = 0; i < V.size.x; i++) {
 139       for (let j = 0; j < V.size.y; j++) {
 140         if (this.board[i][j] != V.EMPTY && this.getColor(i, j) == color) {
 141           if (this.getPotentialMovesFrom([i, j]).length > 0) return true;
 142         }
 143       }
 144     }
 145     return false;
 146   }
 147
 148   getCurrentScore() {
 149     const color = this.turn;
 150     // Did a king change color?
 151     const kp = this.kingPos[color];
 152     if (this.getColor(kp[0], kp[1]) != color)
 153       return color == "w" ? "0-1" : "1-0";
 154     if (this.atLeastOneMove()) return "*";
 155     // Stalemate:
 156     return "1/2";
 157   }
 158
 159   getNotation(move) {
 160     // Just remove flips:
 161     const basicMove = {
 162       appear: [move.appear[0]],
 163       vanish: [move.vanish[0]],
 164       start: move.start,
 165       end: move.end
 166     };
 167     return super.getNotation(basicMove);
 168   }
 169 };