client/src/variants/Janggi.js

   1 import { ChessRules, Move, PiPo } from "@/base_rules";
   2 import { randInt } from "@/utils/alea";
   3
   4 export class JanggiRules extends ChessRules {
   5
   6   static get Monochrome() {
   7     return true;
   8   }
   9
  10   static get Notoodark() {
  11     return true;
  12   }
  13
  14   static get Lines() {
  15     let lines = [];
  16     // Draw all inter-squares lines, shifted:
  17     for (let i = 0; i < V.size.x; i++)
  18       lines.push([[i+0.5, 0.5], [i+0.5, V.size.y-0.5]]);
  19     for (let j = 0; j < V.size.y; j++)
  20       lines.push([[0.5, j+0.5], [V.size.x-0.5, j+0.5]]);
  21     // Add palaces:
  22     lines.push([[0.5, 3.5], [2.5, 5.5]]);
  23     lines.push([[0.5, 5.5], [2.5, 3.5]]);
  24     lines.push([[9.5, 3.5], [7.5, 5.5]]);
  25     lines.push([[9.5, 5.5], [7.5, 3.5]]);
  26     return lines;
  27   }
  28
  29   // No castle, but flag: bikjang
  30   static get HasCastle() {
  31     return false;
  32   }
  33
  34   static get HasEnpassant() {
  35     return false;
  36   }
  37
  38   static get ELEPHANT() {
  39     return "e";
  40   }
  41
  42   static get CANNON() {
  43     return "c";
  44   }
  45
  46   static get ADVISOR() {
  47     return "a";
  48   }
  49
  50   static get PIECES() {
  51     return [V.PAWN, V.ROOK, V.KNIGHT, V.ELEPHANT, V.ADVISOR, V.KING, V.CANNON];
  52   }
  53
  54   getPpath(b) {
  55     return "Janggi/" + b;
  56   }
  57
  58   static get size() {
  59     return { x: 10, y: 9};
  60   }
  61
  62   static IsGoodFlags(flags) {
  63     // bikjang status of last move + pass
  64     return !!flags.match(/^[0-2]{2,2}$/);
  65   }
  66
  67   aggregateFlags() {
  68     return [this.bikjangFlag, this.passFlag];
  69   }
  70
  71   disaggregateFlags(flags) {
  72     this.bikjangFlag = flags[0];
  73     this.passFlag = flags[1];
  74   }
  75
  76   getFlagsFen() {
  77     return this.bikjangFlag.toString() + this.passFlag.toString()
  78   }
  79
  80   setFlags(fenflags) {
  81     this.bikjangFlag = parseInt(fenflags.charAt(0), 10);
  82     this.passFlag = parseInt(fenflags.charAt(1), 10);
  83   }
  84
  85   setOtherVariables(fen) {
  86     super.setOtherVariables(fen);
  87     // Sub-turn is useful only at first move...
  88     this.subTurn = 1;
  89   }
  90
  91   getPotentialMovesFrom([x, y]) {
  92     let moves = [];
  93     const c = this.getColor(x, y);
  94     const oppCol = V.GetOppCol(c);
  95     if (this.kingPos[c][0] == x && this.kingPos[c][1] == y) {
  96       // Add pass move (might be impossible if undercheck)
  97       moves.push(
  98         new Move({
  99           appear: [],
 100           vanish: [],
 101           start: { x: this.kingPos[c][0], y: this.kingPos[c][1] },
 102           end: { x: this.kingPos[oppCol][0], y: this.kingPos[oppCol][1] }
 103         })
 104       );
 105     }
 106     // TODO: next "if" is mutually exclusive with the block above
 107     if (this.movesCount <= 1) {
 108       const firstRank = (this.movesCount == 0 ? 9 : 0);
 109       const initDestFile = new Map([[1, 2], [7, 6]]);
 110       // Only option is knight / elephant swap:
 111       if (x == firstRank && !!initDestFile.get(y)) {
 112         const destFile = initDestFile.get(y);
 113         moves.push(
 114           new Move({
 115             appear: [
 116               new PiPo({
 117                 x: x,
 118                 y: destFile,
 119                 c: c,
 120                 p: V.KNIGHT
 121               }),
 122               new PiPo({
 123                 x: x,
 124                 y: y,
 125                 c: c,
 126                 p: V.ELEPHANT
 127               })
 128             ],
 129             vanish: [
 130               new PiPo({
 131                 x: x,
 132                 y: y,
 133                 c: c,
 134                 p: V.KNIGHT
 135               }),
 136               new PiPo({
 137                 x: x,
 138                 y: destFile,
 139                 c: c,
 140                 p: V.ELEPHANT
 141               })
 142             ],
 143             start: { x: x, y: y },
 144             end: { x: x, y: destFile }
 145           })
 146         );
 147       }
 148     }
 149     else {
 150       let normalMoves = [];
 151       switch (this.getPiece(x, y)) {
 152         case V.PAWN:
 153           normalMoves = this.getPotentialPawnMoves([x, y]);
 154           break;
 155         case V.ROOK:
 156           normalMoves = this.getPotentialRookMoves([x, y]);
 157           break;
 158         case V.KNIGHT:
 159           normalMoves = this.getPotentialKnightMoves([x, y]);
 160           break;
 161         case V.ELEPHANT:
 162           normalMoves = this.getPotentialElephantMoves([x, y]);
 163           break;
 164         case V.ADVISOR:
 165           normalMoves = this.getPotentialAdvisorMoves([x, y]);
 166           break;
 167         case V.KING:
 168           normalMoves = this.getPotentialKingMoves([x, y]);
 169           break;
 170         case V.CANNON:
 171           normalMoves = this.getPotentialCannonMoves([x, y]);
 172           break;
 173       }
 174       Array.prototype.push.apply(moves, normalMoves);
 175     }
 176     return moves;
 177   }
 178
 179   getPotentialPawnMoves([x, y]) {
 180     const c = this.getColor(x, y);
 181     const oppCol = V.GetOppCol(c);
 182     const shiftX = (c == 'w' ? -1 : 1);
 183     const rank23 = (oppCol == 'w' ? [8, 7] : [1, 2]);
 184     let steps = [[shiftX, 0], [0, -1], [0, 1]];
 185     // Diagonal moves inside enemy palace:
 186     if (y == 4 && x == rank23[0])
 187       Array.prototype.push.apply(steps, [[shiftX, 1], [shiftX, -1]]);
 188     else if (x == rank23[1]) {
 189       if (y == 3) steps.push([shiftX, 1]);
 190       else if (y == 5) steps.push([shiftX, -1]);
 191     }
 192     return super.getSlideNJumpMoves([x, y], steps, "oneStep");
 193   }
 194
 195   knightStepsFromRookStep(step) {
 196     if (step[0] == 0) return [ [1, 2*step[1]], [-1, 2*step[1]] ];
 197     return [ [2*step[0], 1], [2*step[0], -1] ];
 198   }
 199
 200   getPotentialKnightMoves([x, y]) {
 201     let steps = [];
 202     for (let rookStep of ChessRules.steps[V.ROOK]) {
 203       const [i, j] = [x + rookStep[0], y + rookStep[1]];
 204       if (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
 205         Array.prototype.push.apply(steps,
 206           // These moves might be impossible, but need to be checked:
 207           this.knightStepsFromRookStep(rookStep));
 208       }
 209     }
 210     return super.getSlideNJumpMoves([x, y], steps, "oneStep");
 211   }
 212
 213   elephantStepsFromRookStep(step) {
 214     if (step[0] == 0) return [ [2, 3*step[1]], [-2, 3*step[1]] ];
 215     return [ [3*step[0], 2], [3*step[0], -2] ];
 216   }
 217
 218   getPotentialElephantMoves([x, y]) {
 219     let steps = [];
 220     for (let rookStep of ChessRules.steps[V.ROOK]) {
 221       const eSteps = this.elephantStepsFromRookStep(rookStep);
 222       const [i, j] = [x + rookStep[0], y + rookStep[1]];
 223       if (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
 224         // Check second crossing:
 225         const knightSteps = this.knightStepsFromRookStep(rookStep);
 226         for (let k of [0, 1]) {
 227           const [ii, jj] = [x + knightSteps[k][0], y + knightSteps[k][1]];
 228           if (V.OnBoard(ii, jj) && this.board[ii][jj] == V.EMPTY)
 229             steps.push(eSteps[k]); //ok: same ordering
 230         }
 231       }
 232     }
 233     return super.getSlideNJumpMoves([x, y], steps, "oneStep");
 234   }
 235
 236   palacePeopleMoves([x, y]) {
 237     const c = this.getColor(x, y);
 238     let steps = [];
 239     // Orthogonal steps:
 240     if (x < (c == 'w' ? 9 : 2)) steps.push([1, 0]);
 241     if (x > (c == 'w' ? 7 : 0)) steps.push([-1, 0]);
 242     if (y > 3) steps.push([0, -1]);
 243     if (y < 5) steps.push([0, 1]);
 244     // Diagonal steps, if in the middle or corner:
 245     if (
 246       y != 4 &&
 247       (
 248         (c == 'w' && x != 8) ||
 249         (c == 'b' && x != 1)
 250       )
 251     ) {
 252       // In a corner: maximum one diagonal step available
 253       let step = null;
 254       const direction = (c == 'w' ? -1 : 1);
 255       if ((c == 'w' && x == 9) || (c == 'b' && x == 0)) {
 256         // On first line
 257         if (y == 3) step = [direction, 1];
 258         else step = [direction, -1];
 259       }
 260       else if ((c == 'w' && x == 7) || (c == 'b' && x == 2)) {
 261         // On third line
 262         if (y == 3) step = [-direction, 1];
 263         else step = [-direction, -1];
 264       }
 265       steps.push(step);
 266     }
 267     else if (
 268       y == 4 &&
 269       (
 270         (c == 'w' && x == 8) ||
 271         (c == 'b' && x == 1)
 272       )
 273     ) {
 274       // At the middle: all directions available
 275       Array.prototype.push.apply(steps, ChessRules.steps[V.BISHOP]);
 276     }
 277     return super.getSlideNJumpMoves([x, y], steps, "oneStep");
 278   }
 279
 280   getPotentialAdvisorMoves(sq) {
 281     return this.palacePeopleMoves(sq);
 282   }
 283
 284   getPotentialKingMoves(sq) {
 285     return this.palacePeopleMoves(sq);
 286   }
 287
 288   getPotentialRookMoves([x, y]) {
 289     let moves = super.getPotentialRookMoves([x, y]);
 290     if ([3, 5].includes(y) && [0, 2, 7, 9].includes(x)) {
 291       // In a corner of a palace: move along diagonal
 292       const step = [[0, 7].includes(x) ? 1 : -1, 4 - y];
 293       const oppCol = V.GetOppCol(this.getColor(x, y));
 294       for (let i of [1, 2]) {
 295         const [xx, yy] = [x + i * step[0], y + i * step[1]];
 296         if (this.board[xx][yy] == V.EMPTY)
 297           moves.push(this.getBasicMove([x, y], [xx, yy]));
 298         else {
 299           if (this.getColor(xx, yy) == oppCol)
 300             moves.push(this.getBasicMove([x, y], [xx, yy]));
 301           break;
 302         }
 303       }
 304     }
 305     else if (y == 4 && [1, 8].includes(x)) {
 306       // In the middle of a palace: 4 one-diagonal-step to check
 307       Array.prototype.push.apply(
 308         moves,
 309         super.getSlideNJumpMoves([x, y],
 310                                  ChessRules.steps[V.BISHOP],
 311                                  "oneStep")
 312       );
 313     }
 314     return moves;
 315   }
 316
 317   // NOTE: (mostly) duplicated from Shako (TODO?)
 318   getPotentialCannonMoves([x, y]) {
 319     const oppCol = V.GetOppCol(this.turn);
 320     let moves = [];
 321     // Look in every direction until an obstacle (to jump) is met
 322     for (const step of V.steps[V.ROOK]) {
 323       let i = x + step[0];
 324       let j = y + step[1];
 325       while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
 326         i += step[0];
 327         j += step[1];
 328       }
 329       // Then, search for an enemy (if jumped piece isn't a cannon)
 330       if (V.OnBoard(i, j) && this.getPiece(i, j) != V.CANNON) {
 331         i += step[0];
 332         j += step[1];
 333         while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
 334           moves.push(this.getBasicMove([x, y], [i, j]));
 335           i += step[0];
 336           j += step[1];
 337         }
 338         if (
 339           V.OnBoard(i, j) &&
 340           this.getColor(i, j) == oppCol &&
 341           this.getPiece(i, j) != V.CANNON
 342         ) {
 343           moves.push(this.getBasicMove([x, y], [i, j]));
 344         }
 345       }
 346     }
 347     if ([3, 5].includes(y) && [0, 2, 7, 9].includes(x)) {
 348       // In a corner of a palace: hop over next obstacle if possible
 349       const step = [[0, 7].includes(x) ? 1 : -1, 4 - y];
 350       const [x1, y1] = [x + step[0], y + step[1]];
 351       const [x2, y2] = [x + 2 * step[0], y + 2 * step[1]];
 352       if (
 353         this.board[x1][y1] != V.EMPTY &&
 354         this.getPiece(x1, y1) != V.CANNON &&
 355         (
 356           this.board[x2][y2] == V.EMPTY ||
 357           (
 358             this.getColor(x2, y2) == oppCol &&
 359             this.getPiece(x2, y2) != V.CANNON
 360           )
 361         )
 362       ) {
 363         moves.push(this.getBasicMove([x, y], [x2, y2]));
 364       }
 365     }
 366     return moves;
 367   }
 368
 369   // (King) Never attacked by advisor, since it stays in the palace
 370   isAttacked(sq, color) {
 371     return (
 372       this.isAttackedByPawn(sq, color) ||
 373       this.isAttackedByRook(sq, color) ||
 374       this.isAttackedByKnight(sq, color) ||
 375       this.isAttackedByElephant(sq, color) ||
 376       this.isAttackedByCannon(sq, color)
 377     );
 378   }
 379
 380   onPalaceDiagonal([x, y]) {
 381     return (
 382       (y == 4 && [1, 8].includes(x)) ||
 383       ([3, 5].includes(y) && [0, 2, 7, 9].includes(x))
 384     );
 385   }
 386
 387   isAttackedByPawn([x, y], color) {
 388     const shiftX = (color == 'w' ? 1 : -1); //shift from king
 389     if (super.isAttackedBySlideNJump(
 390       [x, y], color, V.PAWN, [[shiftX, 0], [0, 1], [0, -1]], "oneStep")
 391     ) {
 392       return true;
 393     }
 394     if (this.onPalaceDiagonal([x, y])) {
 395       for (let yStep of [-1, 1]) {
 396         const [xx, yy] = [x + shiftX, y + yStep];
 397         if (
 398           this.onPalaceDiagonal([xx,yy]) &&
 399           this.board[xx][yy] != V.EMPTY &&
 400           this.getColor(xx, yy) == color &&
 401           this.getPiece(xx, yy) == V.PAWN
 402         ) {
 403           return true;
 404         }
 405       }
 406     }
 407     return false;
 408   }
 409
 410   knightStepsFromBishopStep(step) {
 411     return [ [2*step[0], step[1]], [step[0], 2*step[1]] ];
 412   }
 413
 414   isAttackedByKnight([x, y], color) {
 415     // Check bishop steps: if empty, look continuation knight step
 416     let steps = [];
 417     for (let s of ChessRules.steps[V.BISHOP]) {
 418       const [i, j] = [x + s[0], y + s[1]];
 419       if (
 420         V.OnBoard(i, j) &&
 421         this.board[i][j] == V.EMPTY
 422       ) {
 423         Array.prototype.push.apply(steps, this.knightStepsFromBishopStep(s));
 424       }
 425     }
 426     return (
 427       super.isAttackedBySlideNJump([x, y], color, V.KNIGHT, steps, "oneStep")
 428     );
 429   }
 430
 431   elephantStepsFromBishopStep(step) {
 432     return [ [3*step[0], 2*step[1]], [2*step[0], 3*step[1]] ];
 433   }
 434
 435   isAttackedByElephant([x, y], color) {
 436     // Check bishop steps: if empty, look continuation elephant step
 437     let steps = [];
 438     for (let s of ChessRules.steps[V.BISHOP]) {
 439       const [i1, j1] = [x + s[0], y + s[1]];
 440       const [i2, j2] = [x + 2*s[0], y + 2*s[1]];
 441       if (
 442         V.OnBoard(i2, j2) && this.board[i2][j2] == V.EMPTY &&
 443         V.OnBoard(i1, j1) && this.board[i1][j1] == V.EMPTY
 444       ) {
 445         Array.prototype.push.apply(steps, this.elephantStepsFromBishopStep(s));
 446       }
 447     }
 448     return (
 449       super.isAttackedBySlideNJump([x, y], color, V.ELEPHANT, steps, "oneStep")
 450     );
 451   }
 452
 453   isAttackedByRook([x, y], color) {
 454     if (super.isAttackedByRook([x, y], color)) return true;
 455     // Also check diagonals, if inside palace
 456     if (this.onPalaceDiagonal([x, y])) {
 457       // TODO: next scan is clearly suboptimal
 458       for (let s of ChessRules.steps[V.BISHOP]) {
 459         for (let i of [1, 2]) {
 460           const [xx, yy] = [x + i * s[0], y + i * s[1]];
 461           if (
 462             V.OnBoard(xx, yy) &&
 463             this.onPalaceDiagonal([xx, yy])
 464           ) {
 465             if (this.board[xx][yy] != V.EMPTY) {
 466               if (
 467                 this.getColor(xx, yy) == color &&
 468                 this.getPiece(xx, yy) == V.ROOK
 469               ) {
 470                 return true;
 471               }
 472               break;
 473             }
 474           }
 475           else continue;
 476         }
 477       }
 478     }
 479     return false;
 480   }
 481
 482   // NOTE: (mostly) duplicated from Shako (TODO?)
 483   isAttackedByCannon([x, y], color) {
 484     // Reversed process: is there an obstacle in line,
 485     // and a cannon next in the same line?
 486     for (const step of V.steps[V.ROOK]) {
 487       let [i, j] = [x+step[0], y+step[1]];
 488       while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
 489         i += step[0];
 490         j += step[1];
 491       }
 492       if (V.OnBoard(i, j) && this.getPiece(i, j) != V.CANNON) {
 493         // Keep looking in this direction
 494         i += step[0];
 495         j += step[1];
 496         while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
 497           i += step[0];
 498           j += step[1];
 499         }
 500         if (
 501           V.OnBoard(i, j) &&
 502           this.getPiece(i, j) == V.CANNON &&
 503           this.getColor(i, j) == color
 504         ) {
 505           return true;
 506         }
 507       }
 508     }
 509     return false;
 510   }
 511
 512   getCurrentScore() {
 513     if ([this.bikjangFlag, this.passFlag].includes(2)) return "1/2";
 514     const color = this.turn;
 515     // super.atLeastOneMove() does not consider passing (OK)
 516     if (this.underCheck(color) && !super.atLeastOneMove())
 517       return (color == "w" ? "0-1" : "1-0");
 518     return "*";
 519   }
 520
 521   static get VALUES() {
 522     return {
 523       p: 2,
 524       r: 13,
 525       n: 5,
 526       e: 3,
 527       a: 3,
 528       c: 7,
 529       k: 1000
 530     };
 531   }
 532
 533   static get SEARCH_DEPTH() {
 534     return 2;
 535   }
 536
 537   static GenRandInitFen() {
 538     // No randomization here (but initial setup choice)
 539     return (
 540       "rnea1aenr/4k4/1c5c1/p1p1p1p1p/9/9/P1P1P1P1P/1C5C1/4K4/RNEA1AENR w 0 00"
 541     );
 542   }
 543
 544   play(move) {
 545     move.subTurn = this.subTurn; //much easier
 546     if (this.movesCount >= 2 || this.subTurn == 2 || move.vanish.length == 0) {
 547       this.turn = V.GetOppCol(this.turn);
 548       this.subTurn = 1;
 549       this.movesCount++;
 550     }
 551     else this.subTurn = 2;
 552     move.flags = JSON.stringify(this.aggregateFlags());
 553     V.PlayOnBoard(this.board, move);
 554     this.postPlay(move);
 555   }
 556
 557   postPlay(move) {
 558     if (move.vanish.length > 0) super.postPlay(move);
 559     else if (this.movesCount > 2) this.passFlag++;
 560     // Update bikjang flag
 561     if (this.kingPos['w'][1] == this.kingPos['b'][1]) {
 562       const y = this.kingPos['w'][1];
 563       let bikjang = true;
 564       for (let x = this.kingPos['b'][0] + 1; x < this.kingPos['w'][0]; x++) {
 565         if (this.board[x][y] != V.EMPTY) {
 566           bikjang = false;
 567           break;
 568         }
 569       }
 570       if (bikjang) this.bikjangFlag++;
 571       else this.bikjangFlag = 0;
 572     }
 573     else this.bikjangFlag = 0;
 574   }
 575
 576   undo(move) {
 577     this.disaggregateFlags(JSON.parse(move.flags));
 578     V.UndoOnBoard(this.board, move);
 579     this.postUndo(move);
 580     if (this.movesCount >= 2 || this.subTurn == 1 || move.vanish.length == 0) {
 581       this.turn = V.GetOppCol(this.turn);
 582       this.movesCount--;
 583     }
 584     this.subTurn = move.subTurn;
 585   }
 586
 587   postUndo(move) {
 588     if (move.vanish.length > 0) super.postUndo(move);
 589   }
 590
 591   getComputerMove() {
 592     if (this.movesCount <= 1) {
 593       // Special case: swap and pass at random
 594       const moves1 = this.getAllValidMoves();
 595       const m1 = moves1[randInt(moves1.length)];
 596       this.play(m1);
 597       if (m1.vanish.length == 0) {
 598         this.undo(m1);
 599         return m1;
 600       }
 601       const moves2 = this.getAllValidMoves();
 602       const m2 = moves2[randInt(moves2.length)];
 603       this.undo(m1);
 604       return [m1, m2];
 605     }
 606     return super.getComputerMove();
 607   }
 608
 609   getNotation(move) {
 610     if (move.vanish.length == 0) return "pass";
 611     if (move.appear.length == 2) return "S"; //"swap"
 612     let notation = super.getNotation(move);
 613     if (move.vanish.length == 2 && move.vanish[0].p == V.PAWN)
 614       notation = "P" + notation.substr(1);
 615     return notation;
 616   }
 617
 618 };