client/src/variants/Hidden.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 HiddenRules extends ChessRules {
   6   static get HasFlags() {
   7     return false;
   8   }
   9
  10   static get HasCastle() {
  11     return false;
  12   }
  13
  14   static get HasEnpassant() {
  15     return false;
  16   }
  17
  18   // Analyse in Hidden mode makes no sense
  19   static get CanAnalyze() {
  20     return false;
  21   }
  22
  23   // Moves are revealed only when game ends, but are highlighted on board
  24   static get ShowMoves() {
  25     return "highlight";
  26   }
  27
  28   static get HIDDEN_DECODE() {
  29     return {
  30       s: "p",
  31       t: "q",
  32       u: "r",
  33       c: "b",
  34       o: "n",
  35       l: "k"
  36     };
  37   }
  38   static get HIDDEN_CODE() {
  39     return {
  40       p: "s",
  41       q: "t",
  42       r: "u",
  43       b: "c",
  44       n: "o",
  45       k: "l"
  46     };
  47   }
  48
  49   // Turn a hidden piece or revealed piece into revealed piece:
  50   static Decode(p) {
  51     if (Object.keys(V.HIDDEN_DECODE).includes(p))
  52       return V.HIDDEN_DECODE[p];
  53     return p;
  54   }
  55
  56   static get PIECES() {
  57     return ChessRules.PIECES.concat(Object.values(V.HIDDEN_CODE));
  58   }
  59
  60   // Pieces can be hidden :)
  61   getPiece(i, j) {
  62     const piece = this.board[i][j].charAt(1);
  63     if (Object.keys(V.HIDDEN_DECODE).includes(piece))
  64       return V.HIDDEN_DECODE[piece];
  65     return piece;
  66   }
  67
  68   getPpath(b, color, score) {
  69     if (Object.keys(V.HIDDEN_DECODE).includes(b[1])) {
  70       // Supposed to be hidden.
  71       if (score == "*" && (!color || color != b[0]))
  72         return "Hidden/" + b[0] + "p";
  73       // Else: condition OK to show the piece
  74       return b[0] + V.HIDDEN_DECODE[b[1]];
  75     }
  76     // The piece is already not supposed to be hidden:
  77     return b;
  78   }
  79
  80   // Scan board for kings positions (no castling)
  81   scanKings(fen) {
  82     this.kingPos = { w: [-1, -1], b: [-1, -1] };
  83     const fenRows = V.ParseFen(fen).position.split("/");
  84     for (let i = 0; i < fenRows.length; i++) {
  85       let k = 0; //column index on board
  86       for (let j = 0; j < fenRows[i].length; j++) {
  87         switch (fenRows[i].charAt(j)) {
  88           case "k":
  89           case "l":
  90             this.kingPos["b"] = [i, k];
  91             break;
  92           case "K":
  93           case "L":
  94             this.kingPos["w"] = [i, k];
  95             break;
  96           default: {
  97             const num = parseInt(fenRows[i].charAt(j));
  98             if (!isNaN(num)) k += num - 1;
  99           }
 100         }
 101         k++;
 102       }
 103     }
 104   }
 105
 106   getBasicMove([sx, sy], [ex, ey], tr) {
 107     if (
 108       tr &&
 109       Object.keys(V.HIDDEN_DECODE).includes(this.board[sx][sy].charAt(1))
 110     ) {
 111       // The transformed piece is a priori hidden
 112       tr.p = V.HIDDEN_CODE[tr.p];
 113     }
 114     let mv = new Move({
 115       appear: [
 116         new PiPo({
 117           x: ex,
 118           y: ey,
 119           c: tr ? tr.c : this.getColor(sx, sy),
 120           p: tr ? tr.p : this.board[sx][sy].charAt(1)
 121         })
 122       ],
 123       vanish: [
 124         new PiPo({
 125           x: sx,
 126           y: sy,
 127           c: this.getColor(sx, sy),
 128           p: this.board[sx][sy].charAt(1)
 129         })
 130       ]
 131     });
 132
 133     // The opponent piece disappears if we take it
 134     if (this.board[ex][ey] != V.EMPTY) {
 135       mv.vanish.push(
 136         new PiPo({
 137           x: ex,
 138           y: ey,
 139           c: this.getColor(ex, ey),
 140           p: this.board[ex][ey].charAt(1)
 141         })
 142       );
 143       // Pieces are revealed when they capture
 144       mv.appear[0].p = V.Decode(mv.appear[0].p);
 145     }
 146
 147     return mv;
 148   }
 149
 150   filterValid(moves) {
 151     return moves;
 152   }
 153
 154   // Ignore randomness here: placement is always random asymmetric
 155   static GenRandInitFen() {
 156     let pieces = { w: new Array(8), b: new Array(8) };
 157     // Shuffle pieces + pawns on two first ranks
 158     for (let c of ["w", "b"]) {
 159       let positions = ArrayFun.range(16);
 160
 161       // Get random squares for bishops
 162       let randIndex = 2 * randInt(8);
 163       const bishop1Pos = positions[randIndex];
 164       // The second bishop must be on a square of different color
 165       let randIndex_tmp = 2 * randInt(8) + 1;
 166       const bishop2Pos = positions[randIndex_tmp];
 167       // Remove chosen squares
 168       positions.splice(Math.max(randIndex, randIndex_tmp), 1);
 169       positions.splice(Math.min(randIndex, randIndex_tmp), 1);
 170
 171       // Get random squares for knights
 172       randIndex = randInt(14);
 173       const knight1Pos = positions[randIndex];
 174       positions.splice(randIndex, 1);
 175       randIndex = randInt(13);
 176       const knight2Pos = positions[randIndex];
 177       positions.splice(randIndex, 1);
 178
 179       // Get random squares for rooks
 180       randIndex = randInt(12);
 181       const rook1Pos = positions[randIndex];
 182       positions.splice(randIndex, 1);
 183       randIndex = randInt(11);
 184       const rook2Pos = positions[randIndex];
 185       positions.splice(randIndex, 1);
 186
 187       // Get random square for queen
 188       randIndex = randInt(10);
 189       const queenPos = positions[randIndex];
 190       positions.splice(randIndex, 1);
 191
 192       // Get random square for king
 193       randIndex = randInt(9);
 194       const kingPos = positions[randIndex];
 195       positions.splice(randIndex, 1);
 196
 197       // Pawns position are all remaining slots:
 198       for (let p of positions)
 199         pieces[c][p] = "s";
 200
 201       // Finally put the shuffled pieces in the board array
 202       pieces[c][rook1Pos] = "u";
 203       pieces[c][knight1Pos] = "o";
 204       pieces[c][bishop1Pos] = "c";
 205       pieces[c][queenPos] = "t";
 206       pieces[c][kingPos] = "l";
 207       pieces[c][bishop2Pos] = "c";
 208       pieces[c][knight2Pos] = "o";
 209       pieces[c][rook2Pos] = "u";
 210     }
 211     let upFen = pieces["b"].join("");
 212     upFen = upFen.substr(0,8) + "/" + upFen.substr(8).split("").reverse().join("");
 213     let downFen = pieces["b"].join("").toUpperCase();
 214     downFen = downFen.substr(0,8) + "/" + downFen.substr(8).split("").reverse().join("");
 215     return upFen + "/8/8/8/8/" + downFen + " w 0";
 216   }
 217
 218   getCheckSquares() {
 219     return [];
 220   }
 221
 222   postPlay(move) {
 223     super.postPlay(move);
 224     if (
 225       move.vanish.length >= 2 &&
 226       [V.KING,V.HIDDEN_CODE[V.KING]].includes(move.vanish[1].p)
 227     ) {
 228       // We took opponent king
 229       this.kingPos[this.turn] = [-1, -1];
 230     }
 231   }
 232
 233   postUndo(move) {
 234     super.postUndo(move);
 235     const c = move.vanish[0].c;
 236     const oppCol = V.GetOppCol(c);
 237     if (this.kingPos[oppCol][0] < 0)
 238       // Last move took opponent's king:
 239       this.kingPos[oppCol] = [move.vanish[1].x, move.vanish[1].y];
 240   }
 241
 242   getCurrentScore() {
 243     const color = this.turn;
 244     const kp = this.kingPos[color];
 245     if (kp[0] < 0)
 246       // King disappeared
 247       return color == "w" ? "0-1" : "1-0";
 248     // Assume that stalemate is impossible:
 249     return "*";
 250   }
 251
 252   getComputerMove() {
 253     const color = this.turn;
 254     let moves = this.getAllValidMoves();
 255     for (let move of moves) {
 256       move.eval = 0; //a priori...
 257
 258       // Can I take something ? If yes, do it with some probability
 259       if (move.vanish.length == 2 && move.vanish[1].c != color) {
 260         // OK this isn't a castling move
 261         const myPieceVal = V.VALUES[move.appear[0].p];
 262         const hisPieceVal = Object.keys(V.HIDDEN_DECODE).includes(move.vanish[1].p)
 263           ? undefined
 264           : V.VALUES[move.vanish[1].p];
 265         if (!hisPieceVal) {
 266           // Opponent's piece is unknown: do not take too much risk
 267           move.eval = -myPieceVal + 1.5; //so that pawns always take
 268         }
 269         // Favor captures
 270         else if (myPieceVal <= hisPieceVal)
 271           move.eval = hisPieceVal - myPieceVal + 1;
 272         else {
 273           // Taking a pawn with minor piece,
 274           // or minor piece or pawn with a rook,
 275           // or anything but a queen with a queen,
 276           // or anything with a king.
 277           move.eval = hisPieceVal - myPieceVal;
 278         }
 279       } else {
 280         // If no capture, favor small step moves,
 281         // but sometimes move the knight anyway
 282         const penalty = V.Decode(move.vanish[0].p) != V.KNIGHT
 283           ? Math.abs(move.end.x - move.start.x) + Math.abs(move.end.y - move.start.y)
 284           : (Math.random() < 0.5 ? 3 : 1);
 285         move.eval -= penalty / (V.size.x + V.size.y - 1);
 286       }
 287
 288       // TODO: also favor movements toward the center?
 289     }
 290
 291     moves.sort((a, b) => b.eval - a.eval);
 292     let candidates = [0];
 293     for (let j = 1; j < moves.length && moves[j].eval == moves[0].eval; j++)
 294       candidates.push(j);
 295     return moves[candidates[randInt(candidates.length)]];
 296   }
 297
 298   getNotation(move) {
 299     // Translate final square
 300     const finalSquare = V.CoordsToSquare(move.end);
 301
 302     const piece = this.getPiece(move.start.x, move.start.y);
 303     if (piece == V.PAWN) {
 304       // Pawn move
 305       let notation = "";
 306       if (move.vanish.length > move.appear.length) {
 307         // Capture
 308         const startColumn = V.CoordToColumn(move.start.y);
 309         notation = startColumn + "x" + finalSquare;
 310       }
 311       else notation = finalSquare;
 312       if (move.appear.length > 0 && !["p","s"].includes(move.appear[0].p)) {
 313         // Promotion
 314         const appearPiece = V.Decode(move.appear[0].p);
 315         notation += "=" + appearPiece.toUpperCase();
 316       }
 317       return notation;
 318     }
 319     // Piece movement
 320     return (
 321       piece.toUpperCase() +
 322       (move.vanish.length > move.appear.length ? "x" : "") +
 323       finalSquare
 324     );
 325   }
 326 };