client/src/variants/Hiddenqueen.js

   1 import { ChessRules, PiPo, Move } from "@/base_rules";
   2 import { ArrayFun } from "@/utils/array";
   3 import { randInt } from "@/utils/alea";
   4
   5 export class HiddenqueenRules extends ChessRules {
   6
   7   // Analyse in Hiddenqueen mode makes no sense
   8   static get CanAnalyze() {
   9     return false;
  10   }
  11
  12   static get HIDDEN_QUEEN() {
  13     return 't';
  14   }
  15
  16   static get SomeHiddenMoves() {
  17     return true;
  18   }
  19
  20   static get PIECES() {
  21     return ChessRules.PIECES.concat([V.HIDDEN_QUEEN]);
  22   }
  23
  24   getPiece(i, j) {
  25     const piece = this.board[i][j].charAt(1);
  26     if (
  27       piece != V.HIDDEN_QUEEN ||
  28       // 'side' is used to determine what I see: a pawn or a (hidden)queen?
  29       this.getColor(i, j) == this.side
  30     ) {
  31       return piece;
  32     }
  33     return V.PAWN;
  34   }
  35
  36   getPpath(b, color, score) {
  37     if (b[1] == V.HIDDEN_QUEEN) {
  38       // Supposed to be hidden.
  39       if (score == "*" && (!color || color != b[0]))
  40         return b[0] + "p";
  41       return "Hiddenqueen/" + b[0] + "t";
  42     }
  43     return b;
  44   }
  45
  46   getEpSquare(moveOrSquare) {
  47     if (!moveOrSquare) return undefined;
  48     if (typeof moveOrSquare === "string") {
  49       const square = moveOrSquare;
  50       if (square == "-") return undefined;
  51       return V.SquareToCoords(square);
  52     }
  53     const move = moveOrSquare;
  54     const s = move.start,
  55           e = move.end;
  56     const color = move.vanish[0].c;
  57     if (
  58       s.y == e.y &&
  59       Math.abs(s.x - e.x) == 2 &&
  60       ((color == 'w' && s.x == 6) || (color == 'b' && s.x == 1)) &&
  61       [V.PAWN, V.HIDDEN_QUEEN].includes(move.vanish[0].p)
  62     ) {
  63       return {
  64         x: (s.x + e.x) / 2,
  65         y: s.y
  66       };
  67     }
  68     return undefined; //default
  69   }
  70
  71   isValidPawnMove(move) {
  72     const color = move.vanish[0].c;
  73     const pawnShift = color == "w" ? -1 : 1;
  74     const startRank = color == "w" ? V.size.x - 2 : 1;
  75     return (
  76       (
  77         move.end.x - move.start.x == pawnShift &&
  78         (
  79           (
  80             // Normal move
  81             move.end.y == move.start.y &&
  82             this.board[move.end.x][move.end.y] == V.EMPTY
  83           )
  84           ||
  85           (
  86             // Capture
  87             Math.abs(move.end.y - move.start.y) == 1 &&
  88             this.board[move.end.x][move.end.y] != V.EMPTY
  89           )
  90         )
  91       )
  92       ||
  93       (
  94         // Two-spaces initial jump
  95         move.start.x == startRank &&
  96         move.end.y == move.start.y &&
  97         move.end.x - move.start.x == 2 * pawnShift &&
  98         this.board[move.end.x][move.end.y] == V.EMPTY
  99       )
 100     );
 101   }
 102
 103   getPotentialMovesFrom([x, y]) {
 104     if (this.getPiece(x, y) == V.HIDDEN_QUEEN) {
 105       const pawnMoves = this.getPotentialPawnMoves([x, y]);
 106       let queenMoves = super.getPotentialQueenMoves([x, y]);
 107       // Remove from queen moves those corresponding to a pawn move:
 108       queenMoves = queenMoves
 109         .filter(m => !this.isValidPawnMove(m))
 110         // Hidden queen is revealed if moving like a queen:
 111         .map(m => {
 112           m.appear[0].p = V.QUEEN;
 113           return m;
 114         });
 115       return pawnMoves.concat(queenMoves);
 116     }
 117     return super.getPotentialMovesFrom([x, y]);
 118   }
 119
 120   getEnpassantCaptures([x, y], shiftX) {
 121     const Lep = this.epSquares.length;
 122     const epSquare = this.epSquares[Lep - 1];
 123     let enpassantMove = null;
 124     if (
 125       !!epSquare &&
 126       epSquare.x == x + shiftX &&
 127       Math.abs(epSquare.y - y) == 1
 128     ) {
 129       enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]);
 130       enpassantMove.vanish.push({
 131         x: x,
 132         y: epSquare.y,
 133         // Captured piece may be a hidden queen
 134         p: this.board[x][epSquare.y][1],
 135         c: this.getColor(x, epSquare.y)
 136       });
 137     }
 138     return !!enpassantMove ? [enpassantMove] : [];
 139   }
 140
 141   getPotentialPawnMoves([x, y]) {
 142     const piece = this.getPiece(x, y);
 143     const promotions =
 144       piece == V.PAWN
 145         ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN]
 146         : [V.QUEEN]; //hidden queen revealed
 147     return super.getPotentialPawnMoves([x, y], promotions);
 148   }
 149
 150   getPossibleMovesFrom(sq) {
 151     this.side = this.turn;
 152     return this.filterValid(this.getPotentialMovesFrom(sq));
 153   }
 154
 155   static GenRandInitFen(options) {
 156     let fen = ChessRules.GenRandInitFen(options);
 157     // Place hidden queens at random (always):
 158     let hiddenQueenPos = randInt(8);
 159     let pawnRank = "PPPPPPPP".split("");
 160     pawnRank[hiddenQueenPos] = "T";
 161     fen = fen.replace("PPPPPPPP", pawnRank.join(""));
 162     hiddenQueenPos = randInt(8);
 163     pawnRank = "pppppppp".split("");
 164     pawnRank[hiddenQueenPos] = "t";
 165     fen = fen.replace("pppppppp", pawnRank.join(""));
 166     return fen;
 167   }
 168
 169   postPlay(move) {
 170     super.postPlay(move);
 171     if (move.vanish.length == 2 && move.vanish[1].p == V.KING)
 172       // We took opponent king
 173       this.kingPos[this.turn] = [-1, -1];
 174   }
 175
 176   preUndo(move) {
 177     super.preUndo(move);
 178     const oppCol = this.turn;
 179     if (this.kingPos[oppCol][0] < 0)
 180       // Move takes opponent's king:
 181       this.kingPos[oppCol] = [move.vanish[1].x, move.vanish[1].y];
 182   }
 183
 184   underCheck(color) {
 185     if (this.kingPos[color][0] < 0) return false;
 186     return super.underCheck(color);
 187   }
 188
 189   getCurrentScore() {
 190     const color = this.turn;
 191     if (this.kingPos[color][0] < 0)
 192       // King disappeared
 193       return (color == "w" ? "0-1" : "1-0");
 194     const oldSide = this.side;
 195     this.side = color;
 196     const res = super.getCurrentScore();
 197     this.side = oldSide;
 198     return res;
 199   }
 200
 201   // Search is biased, so not really needed to explore deeply
 202   static get SEARCH_DEPTH() {
 203     return 2;
 204   }
 205
 206   static get VALUES() {
 207     return Object.assign(
 208       { t: 9 },
 209       ChessRules.VALUES
 210     );
 211   }
 212
 213   getComputerMove() {
 214     this.side = this.turn;
 215     return super.getComputerMove();
 216   }
 217
 218   getNotation(move) {
 219     // Not using getPiece() method because it would transform HQ into pawn:
 220     if (this.board[move.start.x][move.start.y].charAt(1) != V.HIDDEN_QUEEN)
 221       return super.getNotation(move);
 222     const finalSquare = V.CoordsToSquare(move.end);
 223     if (move.appear[0].p == V.QUEEN) {
 224       return (
 225         "Q" +
 226         (move.vanish.length > move.appear.length ? "x" : "") +
 227         finalSquare
 228       );
 229     }
 230     // Do not reveal hidden queens playing as pawns
 231     let notation = "";
 232     if (move.vanish.length == 2)
 233       // Capture
 234       notation = V.CoordToColumn(move.start.y) + "x" + finalSquare;
 235     else notation = finalSquare;
 236     return notation;
 237   }
 238
 239 };