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 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]{12,12}$/))
  13       return false;
  14     return true;
  15   }
  16
  17   static IsGoodEnpassant(enpassant) {
  18     if (enpassant != "-") return !!enpassant.match(/^([a-j][0-9]{1,2},?)+$/);
  19     return true;
  20   }
  21
  22   static ParseFen(fen) {
  23     const fenParts = fen.split(" ");
  24     return Object.assign(
  25       ChessRules.ParseFen(fen),
  26       { captured: fenParts[5] }
  27     );
  28   }
  29
  30   getPpath(b) {
  31     return ([V.MARSHALL, V.CARDINAL].includes(b[1]) ? "Grand/" : "") + b;
  32   }
  33
  34   getFen() {
  35     return super.getFen() + " " + this.getCapturedFen();
  36   }
  37
  38   getFenForRepeat() {
  39     return super.getFenForRepeat() + "_" + this.getCapturedFen();
  40   }
  41
  42   getCapturedFen() {
  43     let counts = [...Array(12).fill(0)];
  44     let i = 0;
  45     for (let j = 0; j < V.PIECES.length; j++) {
  46       if ([V.KING, V.PAWN].includes(V.PIECES[j]))
  47         // No king captured, and pawns don't promote in pawns
  48         continue;
  49       counts[i] = this.captured["w"][V.PIECES[j]];
  50       counts[6 + i] = this.captured["b"][V.PIECES[j]];
  51       i++;
  52     }
  53     return counts.join("");
  54   }
  55
  56   setOtherVariables(fen) {
  57     super.setOtherVariables(fen);
  58     const captured =
  59       V.ParseFen(fen).captured.split("").map(x => parseInt(x, 10));
  60     // Initialize captured pieces' counts from FEN
  61     this.captured = {
  62       w: {
  63         [V.ROOK]: captured[0],
  64         [V.KNIGHT]: captured[1],
  65         [V.BISHOP]: captured[2],
  66         [V.QUEEN]: captured[3],
  67         [V.MARSHALL]: captured[4],
  68         [V.CARDINAL]: captured[5]
  69       },
  70       b: {
  71         [V.ROOK]: captured[6],
  72         [V.KNIGHT]: captured[7],
  73         [V.BISHOP]: captured[8],
  74         [V.QUEEN]: captured[9],
  75         [V.MARSHALL]: captured[10],
  76         [V.CARDINAL]: captured[11]
  77       }
  78     };
  79   }
  80
  81   static get size() {
  82     return { x: 10, y: 10 };
  83   }
  84
  85   // Rook + knight:
  86   static get MARSHALL() {
  87     return "m";
  88   }
  89
  90   // Bishop + knight
  91   static get CARDINAL() {
  92     return "c";
  93   }
  94
  95   static get PIECES() {
  96     return ChessRules.PIECES.concat([V.MARSHALL, V.CARDINAL]);
  97   }
  98
  99   // There may be 2 enPassant squares (if pawn jump 3 squares)
 100   getEnpassantFen() {
 101     const L = this.epSquares.length;
 102     if (!this.epSquares[L - 1]) return "-"; //no en-passant
 103     let res = "";
 104     this.epSquares[L - 1].forEach(sq => {
 105       res += V.CoordsToSquare(sq) + ",";
 106     });
 107     return res.slice(0, -1); //remove last comma
 108   }
 109
 110   // En-passant after 2-sq or 3-sq jumps
 111   getEpSquare(moveOrSquare) {
 112     if (!moveOrSquare) return undefined;
 113     if (typeof moveOrSquare === "string") {
 114       const square = moveOrSquare;
 115       if (square == "-") return undefined;
 116       let res = [];
 117       square.split(",").forEach(sq => {
 118         res.push(V.SquareToCoords(sq));
 119       });
 120       return res;
 121     }
 122     // Argument is a move:
 123     const move = moveOrSquare;
 124     const [sx, sy, ex] = [move.start.x, move.start.y, move.end.x];
 125     if (this.getPiece(sx, sy) == V.PAWN && Math.abs(sx - ex) >= 2) {
 126       const step = (ex - sx) / Math.abs(ex - sx);
 127       let res = [
 128         {
 129           x: sx + step,
 130           y: sy
 131         }
 132       ];
 133       if (sx + 2 * step != ex) {
 134         // 3-squares jump
 135         res.push({
 136           x: sx + 2 * step,
 137           y: sy
 138         });
 139       }
 140       return res;
 141     }
 142     return undefined; //default
 143   }
 144
 145   getPotentialMovesFrom([x, y]) {
 146     switch (this.getPiece(x, y)) {
 147       case V.MARSHALL:
 148         return this.getPotentialMarshallMoves([x, y]);
 149       case V.CARDINAL:
 150         return this.getPotentialCardinalMoves([x, y]);
 151       default:
 152         return super.getPotentialMovesFrom([x, y]);
 153     }
 154   }
 155
 156   // Special pawn rules: promotions to captured friendly pieces,
 157   // optional on ranks 8-9 and mandatory on rank 10.
 158   getPotentialPawnMoves([x, y]) {
 159     const color = this.turn;
 160     let moves = [];
 161     const [sizeX, sizeY] = [V.size.x, V.size.y];
 162     const shiftX = color == "w" ? -1 : 1;
 163     const startRanks = color == "w" ? [sizeX - 2, sizeX - 3] : [1, 2];
 164     const lastRanks =
 165       color == "w" ? [0, 1, 2] : [sizeX - 1, sizeX - 2, sizeX - 3];
 166     const promotionPieces = [
 167       V.ROOK,
 168       V.KNIGHT,
 169       V.BISHOP,
 170       V.QUEEN,
 171       V.MARSHALL,
 172       V.CARDINAL
 173     ];
 174
 175     // Always x+shiftX >= 0 && x+shiftX < sizeX, because no pawns on last rank
 176     let finalPieces = undefined;
 177     if (lastRanks.includes(x + shiftX)) {
 178       finalPieces = promotionPieces.filter(p => this.captured[color][p] > 0);
 179       if (x + shiftX != lastRanks[0]) finalPieces.push(V.PAWN);
 180     } else finalPieces = [V.PAWN];
 181     if (this.board[x + shiftX][y] == V.EMPTY) {
 182       // One square forward
 183       for (let piece of finalPieces)
 184         moves.push(
 185           this.getBasicMove([x, y], [x + shiftX, y], { c: color, p: piece })
 186         );
 187       if (startRanks.includes(x)) {
 188         if (this.board[x + 2 * shiftX][y] == V.EMPTY) {
 189           // Two squares jump
 190           moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
 191           if (x == startRanks[0] && this.board[x + 3 * shiftX][y] == V.EMPTY) {
 192             // Three squares jump
 193             moves.push(this.getBasicMove([x, y], [x + 3 * shiftX, y]));
 194           }
 195         }
 196       }
 197     }
 198     // Captures
 199     for (let shiftY of [-1, 1]) {
 200       if (
 201         y + shiftY >= 0 &&
 202         y + shiftY < sizeY &&
 203         this.board[x + shiftX][y + shiftY] != V.EMPTY &&
 204         this.canTake([x, y], [x + shiftX, y + shiftY])
 205       ) {
 206         for (let piece of finalPieces) {
 207           moves.push(
 208             this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
 209               c: color,
 210               p: piece
 211             })
 212           );
 213         }
 214       }
 215     }
 216
 217     // En passant
 218     const Lep = this.epSquares.length;
 219     const epSquare = this.epSquares[Lep - 1];
 220     if (!!epSquare) {
 221       for (let epsq of epSquare) {
 222         // TODO: some redundant checks
 223         if (epsq.x == x + shiftX && Math.abs(epsq.y - y) == 1) {
 224           let enpassantMove = this.getBasicMove([x, y], [epsq.x, epsq.y]);
 225           // WARNING: the captured pawn may be diagonally behind us,
 226           // if it's a 3-squares jump and we take on 1st passing square
 227           const px = this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX;
 228           enpassantMove.vanish.push({
 229             x: px,
 230             y: epsq.y,
 231             p: "p",
 232             c: this.getColor(px, epsq.y)
 233           });
 234           moves.push(enpassantMove);
 235         }
 236       }
 237     }
 238
 239     return moves;
 240   }
 241
 242   // TODO: different castle?
 243
 244   getPotentialMarshallMoves(sq) {
 245     return this.getSlideNJumpMoves(sq, V.steps[V.ROOK]).concat(
 246       this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep")
 247     );
 248   }
 249
 250   getPotentialCardinalMoves(sq) {
 251     return this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]).concat(
 252       this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep")
 253     );
 254   }
 255
 256   isAttacked(sq, color) {
 257     return (
 258       super.isAttacked(sq, color) ||
 259       this.isAttackedByMarshall(sq, color) ||
 260       this.isAttackedByCardinal(sq, color)
 261     );
 262   }
 263
 264   isAttackedByMarshall(sq, color) {
 265     return (
 266       this.isAttackedBySlideNJump(sq, color, V.MARSHALL, V.steps[V.ROOK]) ||
 267       this.isAttackedBySlideNJump(
 268         sq,
 269         color,
 270         V.MARSHALL,
 271         V.steps[V.KNIGHT],
 272         "oneStep"
 273       )
 274     );
 275   }
 276
 277   isAttackedByCardinal(sq, color) {
 278     return (
 279       this.isAttackedBySlideNJump(sq, color, V.CARDINAL, V.steps[V.BISHOP]) ||
 280       this.isAttackedBySlideNJump(
 281         sq,
 282         color,
 283         V.CARDINAL,
 284         V.steps[V.KNIGHT],
 285         "oneStep"
 286       )
 287     );
 288   }
 289
 290   postPlay(move) {
 291     super.postPlay(move);
 292     if (move.vanish.length == 2 && move.appear.length == 1)
 293       // Capture: update this.captured
 294       this.captured[move.vanish[1].c][move.vanish[1].p]++;
 295   }
 296
 297   postUndo(move) {
 298     super.postUndo(move);
 299     if (move.vanish.length == 2 && move.appear.length == 1)
 300       this.captured[move.vanish[1].c][move.vanish[1].p]--;
 301   }
 302
 303   static get VALUES() {
 304     return Object.assign(
 305       { c: 5, m: 7 }, //experimental
 306       ChessRules.VALUES
 307     );
 308   }
 309
 310   static get SEARCH_DEPTH() {
 311     return 2;
 312   }
 313
 314   static GenRandInitFen(randomness) {
 315     if (randomness == 0) {
 316       return (
 317         "r8r/1nbqkmcbn1/pppppppppp/91/91/91/91/PPPPPPPPPP/1NBQKMCBN1/R8R " +
 318         // No castling in the official initial setup
 319         "w 0 zzzz - 00000000000000"
 320       );
 321     }
 322
 323     let pieces = { w: new Array(10), b: new Array(10) };
 324     let flags = "";
 325     // Shuffle pieces on first and last rank
 326     for (let c of ["w", "b"]) {
 327       if (c == 'b' && randomness == 1) {
 328         pieces['b'] = pieces['w'];
 329         flags += flags;
 330         break;
 331       }
 332
 333       let positions = ArrayFun.range(10);
 334
 335       // Get random squares for bishops
 336       let randIndex = 2 * randInt(5);
 337       let bishop1Pos = positions[randIndex];
 338       // The second bishop must be on a square of different color
 339       let randIndex_tmp = 2 * randInt(5) + 1;
 340       let bishop2Pos = positions[randIndex_tmp];
 341       // Remove chosen squares
 342       positions.splice(Math.max(randIndex, randIndex_tmp), 1);
 343       positions.splice(Math.min(randIndex, randIndex_tmp), 1);
 344
 345       // Get random squares for knights
 346       randIndex = randInt(8);
 347       let knight1Pos = positions[randIndex];
 348       positions.splice(randIndex, 1);
 349       randIndex = randInt(7);
 350       let knight2Pos = positions[randIndex];
 351       positions.splice(randIndex, 1);
 352
 353       // Get random square for queen
 354       randIndex = randInt(6);
 355       let queenPos = positions[randIndex];
 356       positions.splice(randIndex, 1);
 357
 358       // ...random square for marshall
 359       randIndex = randInt(5);
 360       let marshallPos = positions[randIndex];
 361       positions.splice(randIndex, 1);
 362
 363       // ...random square for cardinal
 364       randIndex = randInt(4);
 365       let cardinalPos = positions[randIndex];
 366       positions.splice(randIndex, 1);
 367
 368       // Rooks and king positions are now fixed,
 369       // because of the ordering rook-king-rook
 370       let rook1Pos = positions[0];
 371       let kingPos = positions[1];
 372       let rook2Pos = positions[2];
 373
 374       // Finally put the shuffled pieces in the board array
 375       pieces[c][rook1Pos] = "r";
 376       pieces[c][knight1Pos] = "n";
 377       pieces[c][bishop1Pos] = "b";
 378       pieces[c][queenPos] = "q";
 379       pieces[c][marshallPos] = "m";
 380       pieces[c][cardinalPos] = "c";
 381       pieces[c][kingPos] = "k";
 382       pieces[c][bishop2Pos] = "b";
 383       pieces[c][knight2Pos] = "n";
 384       pieces[c][rook2Pos] = "r";
 385       flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos);
 386     }
 387     return (
 388       pieces["b"].join("") +
 389       "/pppppppppp/91/91/91/91/91/91/PPPPPPPPPP/" +
 390       pieces["w"].join("").toUpperCase() +
 391       " w 0 " + flags + " - 00000000000000"
 392     );
 393   }
 394 };