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     const lastRank = color == "w" ? 0 : V.size.x - 1;
  46     return (
  47       // The queen is discovered if she reaches the 8th rank,
  48       // even if this would be a technically valid pawn move.
  49       move.end.x != lastRank &&
  50       (
  51         (
  52           move.end.x - move.start.x == pawnShift &&
  53           (
  54             (
  55               // Normal move
  56               move.end.y == move.start.y &&
  57               this.board[move.end.x][move.end.y] == V.EMPTY
  58             )
  59             ||
  60             (
  61               // Capture
  62               Math.abs(move.end.y - move.start.y) == 1 &&
  63               this.board[move.end.x][move.end.y] != V.EMPTY
  64             )
  65           )
  66         )
  67         ||
  68         (
  69           // Two-spaces initial jump
  70           move.start.x == startRank &&
  71           move.end.y == move.start.y &&
  72           move.end.x - move.start.x == 2 * pawnShift &&
  73           this.board[move.end.x][move.end.y] == V.EMPTY
  74         )
  75       )
  76     );
  77   }
  78
  79   getPotentialMovesFrom([x, y]) {
  80     if (this.getPiece(x, y) == V.HIDDEN_QUEEN) {
  81       const pawnMoves = this.getPotentialPawnMoves([x, y]);
  82       let queenMoves = super.getPotentialQueenMoves([x, y]);
  83       // Remove from queen moves those corresponding to a pawn move:
  84       queenMoves = queenMoves
  85         .filter(m => !this.isValidPawnMove(m))
  86         // Hidden queen is revealed if moving like a queen:
  87         .map(m => {
  88           m.appear[0].p = V.QUEEN;
  89           return m;
  90         });
  91       return pawnMoves.concat(queenMoves);
  92     }
  93     return super.getPotentialMovesFrom([x, y]);
  94   }
  95
  96   // TODO: find a more general way to describe pawn movements to avoid
  97   // re-writing almost the same function for several variants.
  98   getPotentialPawnMoves([x, y]) {
  99     const color = this.turn;
 100     const piece = this.getPiece(x, y);
 101     let moves = [];
 102     const [sizeX, sizeY] = [V.size.x, V.size.y];
 103     const shiftX = color == "w" ? -1 : 1;
 104     const startRank = color == "w" ? sizeX - 2 : 1;
 105     const lastRank = color == "w" ? 0 : sizeX - 1;
 106
 107     const finalPieces =
 108       x + shiftX == lastRank
 109         ? piece == V.PAWN
 110           ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN]
 111           : [V.QUEEN] //hidden queen revealed
 112         : piece;
 113     if (this.board[x + shiftX][y] == V.EMPTY) {
 114       // One square forward
 115       for (let p of finalPieces) {
 116         moves.push(
 117           this.getBasicMove([x, y], [x + shiftX, y], {
 118             c: color,
 119             p: p
 120           })
 121         );
 122       }
 123       if (
 124         x == startRank &&
 125         this.board[x + 2 * shiftX][y] == V.EMPTY
 126       ) {
 127         // Two squares jump
 128         moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
 129       }
 130     }
 131     // Captures
 132     for (let shiftY of [-1, 1]) {
 133       if (
 134         y + shiftY >= 0 &&
 135         y + shiftY < sizeY &&
 136         this.board[x + shiftX][y + shiftY] != V.EMPTY &&
 137         this.canTake([x, y], [x + shiftX, y + shiftY])
 138       ) {
 139         for (let p of finalPieces) {
 140           moves.push(
 141             this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
 142               c: color,
 143               p: p
 144             })
 145           );
 146         }
 147       }
 148     }
 149
 150     if (V.HasEnpassant) {
 151       // En passant
 152       const Lep = this.epSquares.length;
 153       const epSquare = this.epSquares[Lep - 1]; //always at least one element
 154       if (
 155         !!epSquare &&
 156         epSquare.x == x + shiftX &&
 157         Math.abs(epSquare.y - y) == 1
 158       ) {
 159         let enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]);
 160         enpassantMove.vanish.push({
 161           x: x,
 162           y: epSquare.y,
 163           p: "p",
 164           c: this.getColor(x, epSquare.y)
 165         });
 166         moves.push(enpassantMove);
 167       }
 168     }
 169
 170     return moves;
 171   }
 172
 173   getPossibleMovesFrom(sq) {
 174     this.side = this.turn;
 175     return this.filterValid(this.getPotentialMovesFrom(sq));
 176   }
 177
 178   static GenRandInitFen(randomness) {
 179     let fen = ChessRules.GenRandInitFen(randomness);
 180     // Place hidden queens at random (always):
 181     let hiddenQueenPos = randInt(8);
 182     let pawnRank = "PPPPPPPP".split("");
 183     pawnRank[hiddenQueenPos] = "T";
 184     fen = fen.replace("PPPPPPPP", pawnRank.join(""));
 185     hiddenQueenPos = randInt(8);
 186     pawnRank = "pppppppp".split("");
 187     pawnRank[hiddenQueenPos] = "t";
 188     fen = fen.replace("pppppppp", pawnRank.join(""));
 189     return fen;
 190   }
 191
 192   updateVariables(move) {
 193     super.updateVariables(move);
 194     if (move.vanish.length == 2 && move.vanish[1].p == V.KING)
 195       // We took opponent king
 196       this.kingPos[this.turn] = [-1, -1];
 197   }
 198
 199   unupdateVariables(move) {
 200     super.unupdateVariables(move);
 201     const c = move.vanish[0].c;
 202     const oppCol = V.GetOppCol(c);
 203     if (this.kingPos[oppCol][0] < 0)
 204       // Last move took opponent's king:
 205       this.kingPos[oppCol] = [move.vanish[1].x, move.vanish[1].y];
 206   }
 207
 208   getCurrentScore() {
 209     const color = this.turn;
 210     if (this.kingPos[color][0] < 0)
 211       // King disappeared
 212       return color == "w" ? "0-1" : "1-0";
 213     return super.getCurrentScore();
 214   }
 215
 216   // Search is biased, so not really needed to explore deeply
 217   static get SEARCH_DEPTH() {
 218     return 2;
 219   }
 220
 221   static get VALUES() {
 222     return Object.assign(
 223       { t: 9 },
 224       ChessRules.VALUES
 225     );
 226   }
 227
 228   getComputerMove() {
 229     this.side = this.turn;
 230     return super.getComputerMove();
 231   }
 232
 233   getNotation(move) {
 234     const notation = super.getNotation(move);
 235     if (notation.charAt(0) == 'T')
 236       // Do not reveal hidden queens
 237       return notation.substr(1);
 238     return notation;
 239   }
 240 };