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   getFenForRepeat() {
  43     return (
  44       this.getBaseFen() + "_" +
  45       this.getTurnFen() + "_" +
  46       this.getFlagsFen() + "_" +
  47       this.getEnpassantFen() + "_" +
  48       this.getCapturedFen()
  49     );
  50   }
  51
  52   getCapturedFen() {
  53     let counts = [...Array(14).fill(0)];
  54     let i = 0;
  55     for (let j = 0; j < V.PIECES.length; j++) {
  56       if (V.PIECES[j] == V.KING)
  57         //no king captured
  58         continue;
  59       counts[i] = this.captured["w"][V.PIECES[i]];
  60       counts[7 + i] = this.captured["b"][V.PIECES[i]];
  61       i++;
  62     }
  63     return counts.join("");
  64   }
  65
  66   setOtherVariables(fen) {
  67     super.setOtherVariables(fen);
  68     const fenParsed = V.ParseFen(fen);
  69     // Initialize captured pieces' counts from FEN
  70     this.captured = {
  71       w: {
  72         [V.PAWN]: parseInt(fenParsed.captured[0]),
  73         [V.ROOK]: parseInt(fenParsed.captured[1]),
  74         [V.KNIGHT]: parseInt(fenParsed.captured[2]),
  75         [V.BISHOP]: parseInt(fenParsed.captured[3]),
  76         [V.QUEEN]: parseInt(fenParsed.captured[4]),
  77         [V.MARSHALL]: parseInt(fenParsed.captured[5]),
  78         [V.CARDINAL]: parseInt(fenParsed.captured[6])
  79       },
  80       b: {
  81         [V.PAWN]: parseInt(fenParsed.captured[7]),
  82         [V.ROOK]: parseInt(fenParsed.captured[8]),
  83         [V.KNIGHT]: parseInt(fenParsed.captured[9]),
  84         [V.BISHOP]: parseInt(fenParsed.captured[10]),
  85         [V.QUEEN]: parseInt(fenParsed.captured[11]),
  86         [V.MARSHALL]: parseInt(fenParsed.captured[12]),
  87         [V.CARDINAL]: parseInt(fenParsed.captured[13])
  88       }
  89     };
  90   }
  91
  92   static get size() {
  93     return { x: 10, y: 10 };
  94   }
  95
  96   static get MARSHALL() {
  97     return "m";
  98   } //rook+knight
  99   static get CARDINAL() {
 100     return "c";
 101   } //bishop+knight
 102
 103   static get PIECES() {
 104     return ChessRules.PIECES.concat([V.MARSHALL, V.CARDINAL]);
 105   }
 106
 107   // There may be 2 enPassant squares (if pawn jump 3 squares)
 108   getEnpassantFen() {
 109     const L = this.epSquares.length;
 110     if (!this.epSquares[L - 1]) return "-"; //no en-passant
 111     let res = "";
 112     this.epSquares[L - 1].forEach(sq => {
 113       res += V.CoordsToSquare(sq) + ",";
 114     });
 115     return res.slice(0, -1); //remove last comma
 116   }
 117
 118   // En-passant after 2-sq or 3-sq jumps
 119   getEpSquare(moveOrSquare) {
 120     if (!moveOrSquare) return undefined;
 121     if (typeof moveOrSquare === "string") {
 122       const square = moveOrSquare;
 123       if (square == "-") return undefined;
 124       let res = [];
 125       square.split(",").forEach(sq => {
 126         res.push(V.SquareToCoords(sq));
 127       });
 128       return res;
 129     }
 130     // Argument is a move:
 131     const move = moveOrSquare;
 132     const [sx, sy, ex] = [move.start.x, move.start.y, move.end.x];
 133     if (this.getPiece(sx, sy) == V.PAWN && Math.abs(sx - ex) >= 2) {
 134       const step = (ex - sx) / Math.abs(ex - sx);
 135       let res = [
 136         {
 137           x: sx + step,
 138           y: sy
 139         }
 140       ];
 141       if (sx + 2 * step != ex) {
 142         //3-squares move
 143         res.push({
 144           x: sx + 2 * step,
 145           y: sy
 146         });
 147       }
 148       return res;
 149     }
 150     return undefined; //default
 151   }
 152
 153   getPotentialMovesFrom([x, y]) {
 154     switch (this.getPiece(x, y)) {
 155       case V.MARSHALL:
 156         return this.getPotentialMarshallMoves([x, y]);
 157       case V.CARDINAL:
 158         return this.getPotentialCardinalMoves([x, y]);
 159       default:
 160         return super.getPotentialMovesFrom([x, y]);
 161     }
 162   }
 163
 164   // Special pawn rules: promotions to captured friendly pieces,
 165   // optional on ranks 8-9 and mandatory on rank 10.
 166   getPotentialPawnMoves([x, y]) {
 167     const color = this.turn;
 168     let moves = [];
 169     const [sizeX, sizeY] = [V.size.x, V.size.y];
 170     const shiftX = color == "w" ? -1 : 1;
 171     const startRanks = color == "w" ? [sizeX - 2, sizeX - 3] : [1, 2];
 172     const lastRanks =
 173       color == "w" ? [0, 1, 2] : [sizeX - 1, sizeX - 2, sizeX - 3];
 174     const promotionPieces = [
 175       V.ROOK,
 176       V.KNIGHT,
 177       V.BISHOP,
 178       V.QUEEN,
 179       V.MARSHALL,
 180       V.CARDINAL
 181     ];
 182
 183     // Always x+shiftX >= 0 && x+shiftX < sizeX, because no pawns on last rank
 184     let finalPieces = undefined;
 185     if (lastRanks.includes(x + shiftX)) {
 186       finalPieces = promotionPieces.filter(p => this.captured[color][p] > 0);
 187       if (x + shiftX != lastRanks[0]) finalPieces.push(V.PAWN);
 188     } else finalPieces = [V.PAWN];
 189     if (this.board[x + shiftX][y] == V.EMPTY) {
 190       // One square forward
 191       for (let piece of finalPieces)
 192         moves.push(
 193           this.getBasicMove([x, y], [x + shiftX, y], { c: color, p: piece })
 194         );
 195       if (startRanks.includes(x)) {
 196         if (this.board[x + 2 * shiftX][y] == V.EMPTY) {
 197           // Two squares jump
 198           moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
 199           if (x == startRanks[0] && this.board[x + 3 * shiftX][y] == V.EMPTY) {
 200             // Three squares jump
 201             moves.push(this.getBasicMove([x, y], [x + 3 * shiftX, y]));
 202           }
 203         }
 204       }
 205     }
 206     // Captures
 207     for (let shiftY of [-1, 1]) {
 208       if (
 209         y + shiftY >= 0 &&
 210         y + shiftY < sizeY &&
 211         this.board[x + shiftX][y + shiftY] != V.EMPTY &&
 212         this.canTake([x, y], [x + shiftX, y + shiftY])
 213       ) {
 214         for (let piece of finalPieces) {
 215           moves.push(
 216             this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
 217               c: color,
 218               p: piece
 219             })
 220           );
 221         }
 222       }
 223     }
 224
 225     // En passant
 226     const Lep = this.epSquares.length;
 227     const epSquare = this.epSquares[Lep - 1];
 228     if (epSquare) {
 229       for (let epsq of epSquare) {
 230         // TODO: some redundant checks
 231         if (epsq.x == x + shiftX && Math.abs(epsq.y - y) == 1) {
 232           var enpassantMove = this.getBasicMove([x, y], [epsq.x, epsq.y]);
 233           // WARNING: the captured pawn may be diagonally behind us,
 234           // if it's a 3-squares jump and we take on 1st passing square
 235           const px = this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX;
 236           enpassantMove.vanish.push({
 237             x: px,
 238             y: epsq.y,
 239             p: "p",
 240             c: this.getColor(px, epsq.y)
 241           });
 242           moves.push(enpassantMove);
 243         }
 244       }
 245     }
 246
 247     return moves;
 248   }
 249
 250   // TODO: different castle?
 251
 252   getPotentialMarshallMoves(sq) {
 253     return this.getSlideNJumpMoves(sq, V.steps[V.ROOK]).concat(
 254       this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep")
 255     );
 256   }
 257
 258   getPotentialCardinalMoves(sq) {
 259     return this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]).concat(
 260       this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep")
 261     );
 262   }
 263
 264   isAttacked(sq, colors) {
 265     return (
 266       super.isAttacked(sq, colors) ||
 267       this.isAttackedByMarshall(sq, colors) ||
 268       this.isAttackedByCardinal(sq, colors)
 269     );
 270   }
 271
 272   isAttackedByMarshall(sq, colors) {
 273     return (
 274       this.isAttackedBySlideNJump(sq, colors, V.MARSHALL, V.steps[V.ROOK]) ||
 275       this.isAttackedBySlideNJump(
 276         sq,
 277         colors,
 278         V.MARSHALL,
 279         V.steps[V.KNIGHT],
 280         "oneStep"
 281       )
 282     );
 283   }
 284
 285   isAttackedByCardinal(sq, colors) {
 286     return (
 287       this.isAttackedBySlideNJump(sq, colors, V.CARDINAL, V.steps[V.BISHOP]) ||
 288       this.isAttackedBySlideNJump(
 289         sq,
 290         colors,
 291         V.CARDINAL,
 292         V.steps[V.KNIGHT],
 293         "oneStep"
 294       )
 295     );
 296   }
 297
 298   updateVariables(move) {
 299     super.updateVariables(move);
 300     if (move.vanish.length == 2 && move.appear.length == 1) {
 301       // Capture: update this.captured
 302       this.captured[move.vanish[1].c][move.vanish[1].p]++;
 303     }
 304     if (move.vanish[0].p != move.appear[0].p) {
 305       // Promotion: update this.captured
 306       this.captured[move.vanish[0].c][move.appear[0].p]--;
 307     }
 308   }
 309
 310   unupdateVariables(move) {
 311     super.unupdateVariables(move);
 312     if (move.vanish.length == 2 && move.appear.length == 1)
 313       this.captured[move.vanish[1].c][move.vanish[1].p]--;
 314     if (move.vanish[0].p != move.appear[0].p)
 315       this.captured[move.vanish[0].c][move.appear[0].p]++;
 316   }
 317
 318   static get VALUES() {
 319     return Object.assign(
 320       { c: 5, m: 7 }, //experimental
 321       ChessRules.VALUES
 322     );
 323   }
 324
 325   static get SEARCH_DEPTH() {
 326     return 2;
 327   }
 328
 329   static GenRandInitFen(randomness) {
 330     if (randomness == 0) {
 331       return "rnbqkmcbnr/pppppppppp/10/10/10/10/10/10/PPPPPPPPPP/RNBQKMCBNR " +
 332         "w 0 1111 - 00000000000000";
 333     }
 334
 335     let pieces = { w: new Array(10), b: new Array(10) };
 336     // Shuffle pieces on first and last rank
 337     for (let c of ["w", "b"]) {
 338       if (c == 'b' && randomness == 1) {
 339         pieces['b'] = pieces['w'];
 340         break;
 341       }
 342
 343       let positions = ArrayFun.range(10);
 344
 345       // Get random squares for bishops
 346       let randIndex = 2 * randInt(5);
 347       let bishop1Pos = positions[randIndex];
 348       // The second bishop must be on a square of different color
 349       let randIndex_tmp = 2 * randInt(5) + 1;
 350       let bishop2Pos = positions[randIndex_tmp];
 351       // Remove chosen squares
 352       positions.splice(Math.max(randIndex, randIndex_tmp), 1);
 353       positions.splice(Math.min(randIndex, randIndex_tmp), 1);
 354
 355       // Get random squares for knights
 356       randIndex = randInt(8);
 357       let knight1Pos = positions[randIndex];
 358       positions.splice(randIndex, 1);
 359       randIndex = randInt(7);
 360       let knight2Pos = positions[randIndex];
 361       positions.splice(randIndex, 1);
 362
 363       // Get random square for queen
 364       randIndex = randInt(6);
 365       let queenPos = positions[randIndex];
 366       positions.splice(randIndex, 1);
 367
 368       // ...random square for marshall
 369       randIndex = randInt(5);
 370       let marshallPos = positions[randIndex];
 371       positions.splice(randIndex, 1);
 372
 373       // ...random square for cardinal
 374       randIndex = randInt(4);
 375       let cardinalPos = positions[randIndex];
 376       positions.splice(randIndex, 1);
 377
 378       // Rooks and king positions are now fixed, because of the ordering rook-king-rook
 379       let rook1Pos = positions[0];
 380       let kingPos = positions[1];
 381       let rook2Pos = positions[2];
 382
 383       // Finally put the shuffled pieces in the board array
 384       pieces[c][rook1Pos] = "r";
 385       pieces[c][knight1Pos] = "n";
 386       pieces[c][bishop1Pos] = "b";
 387       pieces[c][queenPos] = "q";
 388       pieces[c][marshallPos] = "m";
 389       pieces[c][cardinalPos] = "c";
 390       pieces[c][kingPos] = "k";
 391       pieces[c][bishop2Pos] = "b";
 392       pieces[c][knight2Pos] = "n";
 393       pieces[c][rook2Pos] = "r";
 394     }
 395     return (
 396       pieces["b"].join("") +
 397       "/pppppppppp/10/10/10/10/10/10/PPPPPPPPPP/" +
 398       pieces["w"].join("").toUpperCase() +
 399       " w 0 1111 - 00000000000000"
 400     );
 401   }
 402 };