client/src/variants/Shogi.js

   1 import { ChessRules, PiPo, Move } from "@/base_rules";
   2 import { ArrayFun } from "@/utils/array";
   3
   4 export class ShogiRules extends ChessRules {
   5   static get HasFlags() {
   6     return false;
   7   }
   8
   9   static get HasEnpassant() {
  10     return false;
  11   }
  12
  13   static IsGoodFen(fen) {
  14     if (!ChessRules.IsGoodFen(fen)) return false;
  15     const fenParsed = V.ParseFen(fen);
  16     // 3) Check reserves
  17     if (!fenParsed.reserve || !fenParsed.reserve.match(/^[0-9]{14,14}$/))
  18       return false;
  19     return true;
  20   }
  21
  22   static ParseFen(fen) {
  23     const fenParts = fen.split(" ");
  24     return Object.assign(
  25       ChessRules.ParseFen(fen),
  26       { reserve: fenParts[3] }
  27     );
  28   }
  29
  30   // pawns, rooks, knights, bishops and king kept from ChessRules
  31   static get GOLD_G() {
  32     return "g";
  33   }
  34   static get SILVER_G() {
  35     return "s";
  36   }
  37   static get LANCER() {
  38     return "l";
  39   }
  40
  41   // Promoted pieces:
  42   static get P_PAWN() {
  43     return 'q';
  44   }
  45   static get P_KNIGHT() {
  46     return 'o';
  47   }
  48   static get P_SILVER() {
  49     return 't';
  50   }
  51   static get P_LANCER() {
  52     return 'm';
  53   }
  54   static get P_ROOK() {
  55     return 'd';
  56   }
  57   static get P_BISHOP() {
  58     return 'h';
  59   }
  60
  61   static get PIECES() {
  62     return [
  63       ChessRules.PAWN,
  64       ChessRules.ROOK,
  65       ChessRules.KNIGHT,
  66       ChessRules.BISHOP,
  67       ChessRules.KING,
  68       V.GOLD_G,
  69       V.SILVER_G,
  70       V.LANCER,
  71       V.P_PAWN,
  72       V.P_KNIGHT,
  73       V.P_SILVER,
  74       V.P_LANCER,
  75       V.P_ROOK,
  76       V.P_BISHOP
  77     ];
  78   }
  79
  80   getPpath(b, color, score, orientation) {
  81     // 'i' for "inversed":
  82     const suffix = (b[0] == orientation ? "" : "i");
  83     return "Shogi/" + b + suffix;
  84   }
  85
  86   getPPpath(m, orientation) {
  87     return (
  88       this.getPpath(
  89         m.appear[0].c + m.appear[0].p,
  90         null,
  91         null,
  92         orientation
  93       )
  94     );
  95   }
  96
  97   static GenRandInitFen() {
  98     // No randomization for now:
  99     return (
 100       "lnsgkgsnl/1r5b1/ppppppppp/9/9/9/PPPPPPPPP/1B5R1/LNSGKGSNL " +
 101       "w 0 00000000000000"
 102     );
 103   }
 104
 105   getFen() {
 106     return super.getFen() + " " + this.getReserveFen();
 107   }
 108
 109   getFenForRepeat() {
 110     return super.getFenForRepeat() + "_" + this.getReserveFen();
 111   }
 112
 113   getReserveFen() {
 114     let counts = new Array(14);
 115     for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 116       counts[i] = this.reserve["w"][V.RESERVE_PIECES[i]];
 117       counts[6 + i] = this.reserve["b"][V.RESERVE_PIECES[i]];
 118     }
 119     return counts.join("");
 120   }
 121
 122   setOtherVariables(fen) {
 123     super.setOtherVariables(fen);
 124     const fenParsed = V.ParseFen(fen);
 125     // Also init reserves (used by the interface to show landable pieces)
 126     this.reserve = {
 127       w: {
 128         [V.PAWN]: parseInt(fenParsed.reserve[0]),
 129         [V.ROOK]: parseInt(fenParsed.reserve[1]),
 130         [V.BISHOP]: parseInt(fenParsed.reserve[2]),
 131         [V.GOLD_G]: parseInt(fenParsed.reserve[3]),
 132         [V.SILVER_G]: parseInt(fenParsed.reserve[4]),
 133         [V.KNIGHT]: parseInt(fenParsed.reserve[5]),
 134         [V.LANCER]: parseInt(fenParsed.reserve[6])
 135       },
 136       b: {
 137         [V.PAWN]: parseInt(fenParsed.reserve[7]),
 138         [V.ROOK]: parseInt(fenParsed.reserve[8]),
 139         [V.BISHOP]: parseInt(fenParsed.reserve[9]),
 140         [V.GOLD_G]: parseInt(fenParsed.reserve[10]),
 141         [V.SILVER_G]: parseInt(fenParsed.reserve[11]),
 142         [V.KNIGHT]: parseInt(fenParsed.reserve[12]),
 143         [V.LANCER]: parseInt(fenParsed.reserve[13])
 144       }
 145     };
 146   }
 147
 148   getColor(i, j) {
 149     if (i >= V.size.x) return i == V.size.x ? "w" : "b";
 150     return this.board[i][j].charAt(0);
 151   }
 152
 153   getPiece(i, j) {
 154     if (i >= V.size.x) return V.RESERVE_PIECES[j];
 155     return this.board[i][j].charAt(1);
 156   }
 157
 158   static get size() {
 159     return { x: 9, y: 9};
 160   }
 161
 162   getReservePpath(index, color, orientation) {
 163     return (
 164       "Shogi/" + color + V.RESERVE_PIECES[index] +
 165       (color != orientation ? 'i' : '')
 166     );
 167   }
 168
 169   // Ordering on reserve pieces
 170   static get RESERVE_PIECES() {
 171     return (
 172       [V.PAWN, V.ROOK, V.BISHOP, V.GOLD_G, V.SILVER_G, V.KNIGHT, V.LANCER]
 173     );
 174   }
 175
 176   getReserveMoves([x, y]) {
 177     const color = this.turn;
 178     const p = V.RESERVE_PIECES[y];
 179     if (p == V.PAWN) {
 180       var oppCol = V.GetOppCol(color);
 181       var allowedFiles =
 182         [...Array(9).keys()].filter(j =>
 183           [...Array(9).keys()].every(i => {
 184             return (
 185               this.board[i][j] == V.EMPTY ||
 186               this.getColor(i, j) != color ||
 187               this.getPiece(i, j) != V.PAWN
 188             );
 189           })
 190         )
 191     }
 192     if (this.reserve[color][p] == 0) return [];
 193     let moves = [];
 194     const forward = color == 'w' ? -1 : 1;
 195     const lastRanks = color == 'w' ? [0, 1] : [8, 7];
 196     for (let i = 0; i < V.size.x; i++) {
 197       if (
 198         (i == lastRanks[0] && [V.PAWN, V.KNIGHT, V.LANCER].includes(p)) ||
 199         (i == lastRanks[1] && p == V.KNIGHT)
 200       ) {
 201         continue;
 202       }
 203       for (let j = 0; j < V.size.y; j++) {
 204         if (
 205           this.board[i][j] == V.EMPTY &&
 206           (p != V.PAWN || allowedFiles.includes(j))
 207         ) {
 208           let mv = new Move({
 209             appear: [
 210               new PiPo({
 211                 x: i,
 212                 y: j,
 213                 c: color,
 214                 p: p
 215               })
 216             ],
 217             vanish: [],
 218             start: { x: x, y: y }, //a bit artificial...
 219             end: { x: i, y: j }
 220           });
 221           if (p == V.PAWN) {
 222             // Do not drop on checkmate:
 223             this.play(mv);
 224             const res = (this.underCheck(oppCol) && !this.atLeastOneMove());
 225             this.undo(mv);
 226             if (res) continue;
 227           }
 228           moves.push(mv);
 229         }
 230       }
 231     }
 232     return moves;
 233   }
 234
 235   getPotentialMovesFrom([x, y]) {
 236     if (x >= V.size.x) {
 237       // Reserves, outside of board: x == sizeX(+1)
 238       return this.getReserveMoves([x, y]);
 239     }
 240     switch (this.getPiece(x, y)) {
 241       case V.PAWN:
 242         return this.getPotentialPawnMoves([x, y]);
 243       case V.ROOK:
 244         return this.getPotentialRookMoves([x, y]);
 245       case V.KNIGHT:
 246         return this.getPotentialKnightMoves([x, y]);
 247       case V.BISHOP:
 248         return this.getPotentialBishopMoves([x, y]);
 249       case V.SILVER_G:
 250         return this.getPotentialSilverMoves([x, y]);
 251       case V.LANCER:
 252         return this.getPotentialLancerMoves([x, y]);
 253       case V.KING:
 254         return this.getPotentialKingMoves([x, y]);
 255       case V.P_ROOK:
 256         return this.getPotentialDragonMoves([x, y]);
 257       case V.P_BISHOP:
 258         return this.getPotentialHorseMoves([x, y]);
 259       case V.GOLD_G:
 260       case V.P_PAWN:
 261       case V.P_SILVER:
 262       case V.P_KNIGHT:
 263       case V.P_LANCER:
 264         return this.getPotentialGoldMoves([x, y]);
 265     }
 266     return []; //never reached
 267   }
 268
 269   // Modified to take promotions into account
 270   getSlideNJumpMoves([x, y], steps, options) {
 271     const options = options || {};
 272     const color = this.turn;
 273     const oneStep = options.oneStep;
 274     const forcePromoteOnLastRank = options.force;
 275     const promoteInto = options.promote;
 276     const lastRanks = (color == 'w' ? [0, 1, 2] : [9, 8, 7]);
 277     let moves = [];
 278     outerLoop: for (let step of steps) {
 279       let i = x + step[0];
 280       let j = y + step[1];
 281       while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
 282         if (i != lastRanks[0] || !forcePromoteOnLastRank)
 283           moves.push(this.getBasicMove([x, y], [i, j]));
 284         if (!!promoteInto && lastRanks.includes(i)) {
 285           moves.push(
 286             this.getBasicMove(
 287               [x, y], [i, j], { c: color, p: promoteInto })
 288           );
 289         }
 290         if (oneStep) continue outerLoop;
 291         i += step[0];
 292         j += step[1];
 293       }
 294       if (V.OnBoard(i, j) && this.canTake([x, y], [i, j])) {
 295         if (i != lastRanks[0] || !forcePromoteOnLastRank)
 296           moves.push(this.getBasicMove([x, y], [i, j]));
 297         if (!!promoteInto && lastRanks.includes(i)) {
 298           moves.push(
 299             this.getBasicMove(
 300               [x, y], [i, j], { c: color, p: promoteInto })
 301           );
 302         }
 303       }
 304     }
 305     return moves;
 306   }
 307
 308   getPotentialGoldMoves(sq) {
 309     const forward = (this.turn == 'w' ? -1 : 1);
 310     return this.getSlideNJumpMoves(
 311       sq,
 312       V.steps[V.ROOK].concat([ [forward, 1], [forward, -1] ]),
 313       { oneStep: true }
 314     );
 315   }
 316
 317   getPotentialPawnMoves(sq) {
 318     const forward = (this.turn == 'w' ? -1 : 1);
 319     return (
 320       this.getSlideNJumpMoves(
 321         sq,
 322         [[forward, 0]],
 323         {
 324           oneStep: true,
 325           promote: V.P_PAWN,
 326           force: true
 327         }
 328       )
 329     );
 330   }
 331
 332   getPotentialSilverMoves(sq) {
 333     const forward = (this.turn == 'w' ? -1 : 1);
 334     return this.getSlideNJumpMoves(
 335       sq,
 336       V.steps[V.BISHOP].concat([ [forward, 0] ]),
 337       {
 338         oneStep: true,
 339         promote: V.P_SILVER
 340       }
 341     );
 342   }
 343
 344   getPotentialKnightMoves(sq) {
 345     const forward = (this.turn == 'w' ? -2 : 2);
 346     return this.getSlideNJumpMoves(
 347       sq,
 348       [ [forward, 1], [forward, -1] ],
 349       {
 350         oneStep: true,
 351         promote: V.P_KNIGHT,
 352         force: true
 353       }
 354     );
 355   }
 356
 357   getPotentialRookMoves(sq) {
 358     return this.getSlideNJumpMoves(
 359       sq, V.steps[V.ROOK], { promote: V.P_ROOK });
 360   }
 361
 362   getPotentialBishopMoves(sq) {
 363     return this.getSlideNJumpMoves(
 364       sq, V.steps[V.BISHOP], { promote: V.P_BISHOP });
 365   }
 366
 367   getPotentialLancerMoves(sq) {
 368     const forward = (this.turn == 'w' ? -1 : 1);
 369     return this.getSlideNJumpMoves(
 370       sq, [[forward, 0]], { promote: V.P_LANCER });
 371   }
 372
 373   getPotentialDragonMoves(sq) {
 374     return (
 375       this.getSlideNJumpMoves(sq, V.steps[V.ROOK]).concat(
 376       this.getSlideNJumpMoves(sq, V.steps[V.BISHOP], { oneStep: true }))
 377     );
 378   }
 379
 380   getPotentialHorseMoves(sq) {
 381     return (
 382       this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]).concat(
 383       this.getSlideNJumpMoves(sq, V.steps[V.ROOK], { oneStep: true }))
 384     );
 385   }
 386
 387   getPotentialKingMoves(sq) {
 388     return this.getSlideNJumpMoves(
 389       sq,
 390       V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
 391       { oneStep: true }
 392     );
 393   }
 394
 395   isAttacked(sq, color) {
 396     return (
 397       this.isAttackedByPawn(sq, color) ||
 398       this.isAttackedByRook(sq, color) ||
 399       this.isAttackedByDragon(sq, color) ||
 400       this.isAttackedByKnight(sq, color) ||
 401       this.isAttackedByBishop(sq, color) ||
 402       this.isAttackedByHorse(sq, color) ||
 403       this.isAttackedByLancer(sq, color) ||
 404       this.isAttackedBySilver(sq, color) ||
 405       this.isAttackedByGold(sq, color) ||
 406       this.isAttackedByKing(sq, color)
 407     );
 408   }
 409
 410   isAttackedByGold([x, y], color) {
 411     const shift = (color == 'w' ? 1 : -1);
 412     for (let step of V.steps[V.ROOK].concat([[shift, 1], [shift, -1]])) {
 413       const [i, j] = [x + step[0], y + step[1]];
 414       if (
 415         V.OnBoard(i, j) &&
 416         this.board[i][j] != V.EMPTY &&
 417         this.getColor(i, j) == color &&
 418         [V.GOLD_G, V.P_PAWN, V.P_SILVER, V.P_KNIGHT, V.P_LANCER]
 419           .includes(this.getPiece(i, j))
 420       ) {
 421         return true;
 422       }
 423     }
 424     return false;
 425   }
 426
 427   isAttackedBySilver([x, y], color) {
 428     const shift = (color == 'w' ? 1 : -1);
 429     for (let step of V.steps[V.BISHOP].concat([[shift, 0]])) {
 430       const [i, j] = [x + step[0], y + step[1]];
 431       if (
 432         V.OnBoard(i, j) &&
 433         this.board[i][j] != V.EMPTY &&
 434         this.getColor(i, j) == color &&
 435         this.getPiece(i, j) == V.SILVER_G
 436       ) {
 437         return true;
 438       }
 439     }
 440     return false;
 441   }
 442
 443   isAttackedByPawn([x, y], color) {
 444     const shift = (color == 'w' ? 1 : -1);
 445     const [i, j] = [x + shift, y];
 446     return (
 447       V.OnBoard(i, j) &&
 448       this.board[i][j] != V.EMPTY &&
 449       this.getColor(i, j) == color &&
 450       this.getPiece(i, j) == V.PAWN
 451     );
 452   }
 453
 454   isAttackedByKnight(sq, color) {
 455     const forward = (color == 'w' ? 2 : -2);
 456     return this.isAttackedBySlideNJump(
 457       sq, color, V.KNIGHT, [[forward, 1], [forward, -1]], "oneStep");
 458   }
 459
 460   isAttackedByLancer(sq, color) {
 461     const forward = (color == 'w' ? 1 : -1);
 462     return this.isAttackedBySlideNJump(sq, color, V.LANCER, [[forward, 0]]);
 463   }
 464
 465   isAttackedByDragon(sq, color) {
 466     return (
 467       this.isAttackedBySlideNJump(sq, color, V.P_ROOK, V.steps[V.ROOK]) ||
 468       this.isAttackedBySlideNJump(
 469         sq, color, V.DRAGON, V.steps[V.BISHOP], "oneStep")
 470     );
 471   }
 472
 473   isAttackedByHorse(sq, color) {
 474     return (
 475       this.isAttackedBySlideNJump(sq, color, V.P_BISHOP, V.steps[V.BISHOP]) ||
 476       this.isAttackedBySlideNJump(
 477         sq, color, V.DRAGON, V.steps[V.ROOK], "oneStep")
 478     );
 479   }
 480
 481   getAllValidMoves() {
 482     let moves = super.getAllPotentialMoves();
 483     const color = this.turn;
 484     for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 485       moves = moves.concat(
 486         this.getReserveMoves([V.size.x + (color == "w" ? 0 : 1), i])
 487       );
 488     }
 489     return this.filterValid(moves);
 490   }
 491
 492   atLeastOneMove() {
 493     if (!super.atLeastOneMove()) {
 494       // Search one reserve move
 495       for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 496         let moves = this.filterValid(
 497           this.getReserveMoves([V.size.x + (this.turn == "w" ? 0 : 1), i])
 498         );
 499         if (moves.length > 0) return true;
 500       }
 501       return false;
 502     }
 503     return true;
 504   }
 505
 506   static get P_CORRESPONDANCES() {
 507     return {
 508       q: 'p',
 509       o: 'n',
 510       t: 's',
 511       m: 'l',
 512       d: 'r',
 513       h: 'b'
 514     };
 515   }
 516
 517   static MayDecode(piece) {
 518     if (Object.keys(V.P_CORRESPONDANCES).includes(piece))
 519       return V.P_CORRESPONDANCES[piece];
 520     return piece;
 521   }
 522
 523   postPlay(move) {
 524     super.postPlay(move);
 525     const color = move.appear[0].c;
 526     if (move.vanish.length == 0)
 527       // Drop unpromoted piece:
 528       this.reserve[color][move.appear[0].p]--;
 529     else if (move.vanish.length == 2)
 530       // May capture a promoted piece:
 531       this.reserve[color][V.MayDecode(move.vanish[1].p)]++;
 532   }
 533
 534   postUndo(move) {
 535     super.postUndo(move);
 536     const color = this.turn;
 537     if (move.vanish.length == 0)
 538       this.reserve[color][move.appear[0].p]++;
 539     else if (move.vanish.length == 2)
 540       this.reserve[color][V.MayDecode(move.vanish[1].p)]--;
 541   }
 542
 543   static get SEARCH_DEPTH() {
 544     return 2;
 545   }
 546
 547   static get VALUES() {
 548     // TODO: very arbitrary and wrong
 549     return {
 550       p: 1,
 551       q: 3,
 552       r: 5,
 553       d: 6,
 554       n: 2,
 555       o: 3,
 556       b: 3,
 557       h: 4,
 558       s: 3,
 559       t: 3,
 560       l: 2,
 561       m: 3,
 562       g: 3,
 563       k: 1000,
 564     }
 565   }
 566
 567   evalPosition() {
 568     let evaluation = super.evalPosition();
 569     // Add reserves:
 570     for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 571       const p = V.RESERVE_PIECES[i];
 572       evaluation += this.reserve["w"][p] * V.VALUES[p];
 573       evaluation -= this.reserve["b"][p] * V.VALUES[p];
 574     }
 575     return evaluation;
 576   }
 577
 578   getNotation(move) {
 579     const finalSquare = V.CoordsToSquare(move.end);
 580     if (move.vanish.length == 0) {
 581       // Rebirth:
 582       const piece = move.appear[0].p.toUpperCase();
 583       return (piece != 'P' ? piece : "") + "@" + finalSquare;
 584     }
 585     const piece = move.vanish[0].p.toUpperCase();
 586     return (
 587       (piece != 'P' || move.vanish.length == 2 ? piece : "") +
 588       (move.vanish.length == 2 ? "x" : "") +
 589       finalSquare +
 590       (
 591         move.appear[0].p != move.vanish[0].p
 592           ? "=" + move.appear[0].p.toUpperCase()
 593           : ""
 594       )
 595     );
 596   }
 597 };