client/src/variants/Grand.js

   1 import { ChessRules } from "@/base_rules";
   2 import { ArrayFun } from "@/utils/array";
   3 import { randInt } from "@/utils/alea";
   4
   5 // NOTE: initial setup differs from the original; see
   6 // https://www.chessvariants.com/large.dir/freeling.html
   7 export const VariantRules = class GrandRules extends ChessRules {
   8   static IsGoodFen(fen) {
   9     if (!ChessRules.IsGoodFen(fen)) return false;
  10     const fenParsed = V.ParseFen(fen);
  11     // 5) Check captures
  12     if (!fenParsed.captured || !fenParsed.captured.match(/^[0-9]{14,14}$/))
  13       return false;
  14     return true;
  15   }
  16
  17   static IsGoodEnpassant(enpassant) {
  18     if (enpassant != "-") {
  19       const squares = enpassant.split(",");
  20       if (squares.length > 2) return false;
  21       for (let sq of squares) {
  22         const ep = V.SquareToCoords(sq);
  23         if (isNaN(ep.x) || !V.OnBoard(ep)) return false;
  24       }
  25     }
  26     return true;
  27   }
  28
  29   static ParseFen(fen) {
  30     const fenParts = fen.split(" ");
  31     return Object.assign(ChessRules.ParseFen(fen), { captured: fenParts[5] });
  32   }
  33
  34   getPpath(b) {
  35     return ([V.MARSHALL, V.CARDINAL].includes(b[1]) ? "Grand/" : "") + b;
  36   }
  37
  38   getFen() {
  39     return super.getFen() + " " + this.getCapturedFen();
  40   }
  41
  42   getCapturedFen() {
  43     let counts = [...Array(14).fill(0)];
  44     let i = 0;
  45     for (let j = 0; j < V.PIECES.length; j++) {
  46       if (V.PIECES[j] == V.KING)
  47         //no king captured
  48         continue;
  49       counts[i] = this.captured["w"][V.PIECES[i]];
  50       counts[7 + i] = this.captured["b"][V.PIECES[i]];
  51       i++;
  52     }
  53     return counts.join("");
  54   }
  55
  56   setOtherVariables(fen) {
  57     super.setOtherVariables(fen);
  58     const fenParsed = V.ParseFen(fen);
  59     // Initialize captured pieces' counts from FEN
  60     this.captured = {
  61       w: {
  62         [V.PAWN]: parseInt(fenParsed.captured[0]),
  63         [V.ROOK]: parseInt(fenParsed.captured[1]),
  64         [V.KNIGHT]: parseInt(fenParsed.captured[2]),
  65         [V.BISHOP]: parseInt(fenParsed.captured[3]),
  66         [V.QUEEN]: parseInt(fenParsed.captured[4]),
  67         [V.MARSHALL]: parseInt(fenParsed.captured[5]),
  68         [V.CARDINAL]: parseInt(fenParsed.captured[6])
  69       },
  70       b: {
  71         [V.PAWN]: parseInt(fenParsed.captured[7]),
  72         [V.ROOK]: parseInt(fenParsed.captured[8]),
  73         [V.KNIGHT]: parseInt(fenParsed.captured[9]),
  74         [V.BISHOP]: parseInt(fenParsed.captured[10]),
  75         [V.QUEEN]: parseInt(fenParsed.captured[11]),
  76         [V.MARSHALL]: parseInt(fenParsed.captured[12]),
  77         [V.CARDINAL]: parseInt(fenParsed.captured[13])
  78       }
  79     };
  80   }
  81
  82   static get size() {
  83     return { x: 10, y: 10 };
  84   }
  85
  86   static get MARSHALL() {
  87     return "m";
  88   } //rook+knight
  89   static get CARDINAL() {
  90     return "c";
  91   } //bishop+knight
  92
  93   static get PIECES() {
  94     return ChessRules.PIECES.concat([V.MARSHALL, V.CARDINAL]);
  95   }
  96
  97   // There may be 2 enPassant squares (if pawn jump 3 squares)
  98   getEnpassantFen() {
  99     const L = this.epSquares.length;
 100     if (!this.epSquares[L - 1]) return "-"; //no en-passant
 101     let res = "";
 102     this.epSquares[L - 1].forEach(sq => {
 103       res += V.CoordsToSquare(sq) + ",";
 104     });
 105     return res.slice(0, -1); //remove last comma
 106   }
 107
 108   // En-passant after 2-sq or 3-sq jumps
 109   getEpSquare(moveOrSquare) {
 110     if (!moveOrSquare) return undefined;
 111     if (typeof moveOrSquare === "string") {
 112       const square = moveOrSquare;
 113       if (square == "-") return undefined;
 114       let res = [];
 115       square.split(",").forEach(sq => {
 116         res.push(V.SquareToCoords(sq));
 117       });
 118       return res;
 119     }
 120     // Argument is a move:
 121     const move = moveOrSquare;
 122     const [sx, sy, ex] = [move.start.x, move.start.y, move.end.x];
 123     if (this.getPiece(sx, sy) == V.PAWN && Math.abs(sx - ex) >= 2) {
 124       const step = (ex - sx) / Math.abs(ex - sx);
 125       let res = [
 126         {
 127           x: sx + step,
 128           y: sy
 129         }
 130       ];
 131       if (sx + 2 * step != ex) {
 132         //3-squares move
 133         res.push({
 134           x: sx + 2 * step,
 135           y: sy
 136         });
 137       }
 138       return res;
 139     }
 140     return undefined; //default
 141   }
 142
 143   getPotentialMovesFrom([x, y]) {
 144     switch (this.getPiece(x, y)) {
 145       case V.MARSHALL:
 146         return this.getPotentialMarshallMoves([x, y]);
 147       case V.CARDINAL:
 148         return this.getPotentialCardinalMoves([x, y]);
 149       default:
 150         return super.getPotentialMovesFrom([x, y]);
 151     }
 152   }
 153
 154   // Special pawn rules: promotions to captured friendly pieces,
 155   // optional on ranks 8-9 and mandatory on rank 10.
 156   getPotentialPawnMoves([x, y]) {
 157     const color = this.turn;
 158     let moves = [];
 159     const [sizeX, sizeY] = [V.size.x, V.size.y];
 160     const shiftX = color == "w" ? -1 : 1;
 161     const startRanks = color == "w" ? [sizeX - 2, sizeX - 3] : [1, 2];
 162     const lastRanks =
 163       color == "w" ? [0, 1, 2] : [sizeX - 1, sizeX - 2, sizeX - 3];
 164     const promotionPieces = [
 165       V.ROOK,
 166       V.KNIGHT,
 167       V.BISHOP,
 168       V.QUEEN,
 169       V.MARSHALL,
 170       V.CARDINAL
 171     ];
 172
 173     // Always x+shiftX >= 0 && x+shiftX < sizeX, because no pawns on last rank
 174     let finalPieces = undefined;
 175     if (lastRanks.includes(x + shiftX)) {
 176       finalPieces = promotionPieces.filter(p => this.captured[color][p] > 0);
 177       if (x + shiftX != lastRanks[0]) finalPieces.push(V.PAWN);
 178     } else finalPieces = [V.PAWN];
 179     if (this.board[x + shiftX][y] == V.EMPTY) {
 180       // One square forward
 181       for (let piece of finalPieces)
 182         moves.push(
 183           this.getBasicMove([x, y], [x + shiftX, y], { c: color, p: piece })
 184         );
 185       if (startRanks.includes(x)) {
 186         if (this.board[x + 2 * shiftX][y] == V.EMPTY) {
 187           // Two squares jump
 188           moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
 189           if (x == startRanks[0] && this.board[x + 3 * shiftX][y] == V.EMPTY) {
 190             // Three squares jump
 191             moves.push(this.getBasicMove([x, y], [x + 3 * shiftX, y]));
 192           }
 193         }
 194       }
 195     }
 196     // Captures
 197     for (let shiftY of [-1, 1]) {
 198       if (
 199         y + shiftY >= 0 &&
 200         y + shiftY < sizeY &&
 201         this.board[x + shiftX][y + shiftY] != V.EMPTY &&
 202         this.canTake([x, y], [x + shiftX, y + shiftY])
 203       ) {
 204         for (let piece of finalPieces) {
 205           moves.push(
 206             this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
 207               c: color,
 208               p: piece
 209             })
 210           );
 211         }
 212       }
 213     }
 214
 215     // En passant
 216     const Lep = this.epSquares.length;
 217     const epSquare = this.epSquares[Lep - 1];
 218     if (epSquare) {
 219       for (let epsq of epSquare) {
 220         // TODO: some redundant checks
 221         if (epsq.x == x + shiftX && Math.abs(epsq.y - y) == 1) {
 222           var enpassantMove = this.getBasicMove([x, y], [epsq.x, epsq.y]);
 223           // WARNING: the captured pawn may be diagonally behind us,
 224           // if it's a 3-squares jump and we take on 1st passing square
 225           const px = this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX;
 226           enpassantMove.vanish.push({
 227             x: px,
 228             y: epsq.y,
 229             p: "p",
 230             c: this.getColor(px, epsq.y)
 231           });
 232           moves.push(enpassantMove);
 233         }
 234       }
 235     }
 236
 237     return moves;
 238   }
 239
 240   // TODO: different castle?
 241
 242   getPotentialMarshallMoves(sq) {
 243     return this.getSlideNJumpMoves(sq, V.steps[V.ROOK]).concat(
 244       this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep")
 245     );
 246   }
 247
 248   getPotentialCardinalMoves(sq) {
 249     return this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]).concat(
 250       this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep")
 251     );
 252   }
 253
 254   isAttacked(sq, colors) {
 255     return (
 256       super.isAttacked(sq, colors) ||
 257       this.isAttackedByMarshall(sq, colors) ||
 258       this.isAttackedByCardinal(sq, colors)
 259     );
 260   }
 261
 262   isAttackedByMarshall(sq, colors) {
 263     return (
 264       this.isAttackedBySlideNJump(sq, colors, V.MARSHALL, V.steps[V.ROOK]) ||
 265       this.isAttackedBySlideNJump(
 266         sq,
 267         colors,
 268         V.MARSHALL,
 269         V.steps[V.KNIGHT],
 270         "oneStep"
 271       )
 272     );
 273   }
 274
 275   isAttackedByCardinal(sq, colors) {
 276     return (
 277       this.isAttackedBySlideNJump(sq, colors, V.CARDINAL, V.steps[V.BISHOP]) ||
 278       this.isAttackedBySlideNJump(
 279         sq,
 280         colors,
 281         V.CARDINAL,
 282         V.steps[V.KNIGHT],
 283         "oneStep"
 284       )
 285     );
 286   }
 287
 288   updateVariables(move) {
 289     super.updateVariables(move);
 290     if (move.vanish.length == 2 && move.appear.length == 1) {
 291       // Capture: update this.captured
 292       this.captured[move.vanish[1].c][move.vanish[1].p]++;
 293     }
 294     if (move.vanish[0].p != move.appear[0].p) {
 295       // Promotion: update this.captured
 296       this.captured[move.vanish[0].c][move.appear[0].p]--;
 297     }
 298   }
 299
 300   unupdateVariables(move) {
 301     super.unupdateVariables(move);
 302     if (move.vanish.length == 2 && move.appear.length == 1)
 303       this.captured[move.vanish[1].c][move.vanish[1].p]--;
 304     if (move.vanish[0].p != move.appear[0].p)
 305       this.captured[move.vanish[0].c][move.appear[0].p]++;
 306   }
 307
 308   static get VALUES() {
 309     return Object.assign(
 310       { c: 5, m: 7 }, //experimental
 311       ChessRules.VALUES
 312     );
 313   }
 314
 315   static get SEARCH_DEPTH() {
 316     return 2;
 317   }
 318
 319   static GenRandInitFen() {
 320     let pieces = { w: new Array(10), b: new Array(10) };
 321     // Shuffle pieces on first and last rank
 322     for (let c of ["w", "b"]) {
 323       let positions = ArrayFun.range(10);
 324
 325       // Get random squares for bishops
 326       let randIndex = 2 * randInt(5);
 327       let bishop1Pos = positions[randIndex];
 328       // The second bishop must be on a square of different color
 329       let randIndex_tmp = 2 * randInt(5) + 1;
 330       let bishop2Pos = positions[randIndex_tmp];
 331       // Remove chosen squares
 332       positions.splice(Math.max(randIndex, randIndex_tmp), 1);
 333       positions.splice(Math.min(randIndex, randIndex_tmp), 1);
 334
 335       // Get random squares for knights
 336       randIndex = randInt(8);
 337       let knight1Pos = positions[randIndex];
 338       positions.splice(randIndex, 1);
 339       randIndex = randInt(7);
 340       let knight2Pos = positions[randIndex];
 341       positions.splice(randIndex, 1);
 342
 343       // Get random square for queen
 344       randIndex = randInt(6);
 345       let queenPos = positions[randIndex];
 346       positions.splice(randIndex, 1);
 347
 348       // ...random square for marshall
 349       randIndex = randInt(5);
 350       let marshallPos = positions[randIndex];
 351       positions.splice(randIndex, 1);
 352
 353       // ...random square for cardinal
 354       randIndex = randInt(4);
 355       let cardinalPos = positions[randIndex];
 356       positions.splice(randIndex, 1);
 357
 358       // Rooks and king positions are now fixed, because of the ordering rook-king-rook
 359       let rook1Pos = positions[0];
 360       let kingPos = positions[1];
 361       let rook2Pos = positions[2];
 362
 363       // Finally put the shuffled pieces in the board array
 364       pieces[c][rook1Pos] = "r";
 365       pieces[c][knight1Pos] = "n";
 366       pieces[c][bishop1Pos] = "b";
 367       pieces[c][queenPos] = "q";
 368       pieces[c][marshallPos] = "m";
 369       pieces[c][cardinalPos] = "c";
 370       pieces[c][kingPos] = "k";
 371       pieces[c][bishop2Pos] = "b";
 372       pieces[c][knight2Pos] = "n";
 373       pieces[c][rook2Pos] = "r";
 374     }
 375     return (
 376       pieces["b"].join("") +
 377       "/pppppppppp/10/10/10/10/10/10/PPPPPPPPPP/" +
 378       pieces["w"].join("").toUpperCase() +
 379       " w 0 1111 - 00000000000000"
 380     );
 381   }
 382 };