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