Early draft of Paco-Sako + some fixes
[vchess.git] / client / src / base_rules.js
... / ...
CommitLineData
1// (Orthodox) Chess rules are defined in ChessRules class.
2// Variants generally inherit from it, and modify some parts.
3
4import { ArrayFun } from "@/utils/array";
5import { randInt, shuffle } from "@/utils/alea";
6
7// class "PiPo": Piece + Position
8export const PiPo = class PiPo {
9 // o: {piece[p], color[c], posX[x], posY[y]}
10 constructor(o) {
11 this.p = o.p;
12 this.c = o.c;
13 this.x = o.x;
14 this.y = o.y;
15 }
16};
17
18export const Move = class Move {
19 // o: {appear, vanish, [start,] [end,]}
20 // appear,vanish = arrays of PiPo
21 // start,end = coordinates to apply to trigger move visually (think castle)
22 constructor(o) {
23 this.appear = o.appear;
24 this.vanish = o.vanish;
25 this.start = o.start ? o.start : { x: o.vanish[0].x, y: o.vanish[0].y };
26 this.end = o.end ? o.end : { x: o.appear[0].x, y: o.appear[0].y };
27 }
28};
29
30// NOTE: x coords = top to bottom; y = left to right
31// (from white player perspective)
32export const ChessRules = class ChessRules {
33
34 //////////////
35 // MISC UTILS
36
37 // Some variants don't have flags:
38 static get HasFlags() {
39 return true;
40 }
41
42 // Or castle
43 static get HasCastle() {
44 return V.HasFlags;
45 }
46
47 // Pawns specifications
48 static get PawnSpecs() {
49 return {
50 directions: { 'w': -1, 'b': 1 },
51 initShift: { w: 1, b: 1 },
52 twoSquares: true,
53 threeSquares: false,
54 promotions: [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN],
55 canCapture: true,
56 captureBackward: false,
57 bidirectional: false
58 };
59 }
60
61 // En-passant captures need a stack of squares:
62 static get HasEnpassant() {
63 return true;
64 }
65
66 // Some variants cannot have analyse mode
67 static get CanAnalyze() {
68 return true;
69 }
70 // Patch: issues with javascript OOP, objects can't access static fields.
71 get canAnalyze() {
72 return V.CanAnalyze;
73 }
74
75 // Some variants show incomplete information,
76 // and thus show only a partial moves list or no list at all.
77 static get ShowMoves() {
78 return "all";
79 }
80 get showMoves() {
81 return V.ShowMoves;
82 }
83
84 // Sometimes moves must remain hidden until game ends
85 static get SomeHiddenMoves() {
86 return false;
87 }
88 get someHiddenMoves() {
89 return V.SomeHiddenMoves;
90 }
91
92 // Generally true, unless the variant includes random effects
93 static get CorrConfirm() {
94 return true;
95 }
96
97 // Used for Monochrome variant (TODO: harmonize: !canFlip ==> showFirstTurn)
98 get showFirstTurn() {
99 return false;
100 }
101
102 // Some variants always show the same orientation
103 static get CanFlip() {
104 return true;
105 }
106 get canFlip() {
107 return V.CanFlip;
108 }
109
110 // For (generally old) variants without checkered board
111 static get Monochrome() {
112 return false;
113 }
114
115 // Some games are drawn unusually (bottom right corner is black)
116 static get DarkBottomRight() {
117 return false;
118 }
119
120 // Some variants require lines drawing
121 static get Lines() {
122 if (V.Monochrome) {
123 let lines = [];
124 // Draw all inter-squares lines
125 for (let i = 0; i <= V.size.x; i++)
126 lines.push([[i, 0], [i, V.size.y]]);
127 for (let j = 0; j <= V.size.y; j++)
128 lines.push([[0, j], [V.size.x, j]]);
129 return lines;
130 }
131 return null;
132 }
133
134 // In some variants, the player who repeat a position loses
135 static get LoseOnRepetition() {
136 return false;
137 }
138
139 // Some variants use click infos:
140 doClick() {
141 return null;
142 }
143
144 // Some variants may need to highlight squares on hover (Hamilton, Weiqi...)
145 hoverHighlight() {
146 return false;
147 }
148
149 static get IMAGE_EXTENSION() {
150 // All pieces should be in the SVG format
151 return ".svg";
152 }
153
154 // Turn "wb" into "B" (for FEN)
155 static board2fen(b) {
156 return b[0] == "w" ? b[1].toUpperCase() : b[1];
157 }
158
159 // Turn "p" into "bp" (for board)
160 static fen2board(f) {
161 return f.charCodeAt() <= 90 ? "w" + f.toLowerCase() : "b" + f;
162 }
163
164 // Check if FEN describes a board situation correctly
165 static IsGoodFen(fen) {
166 const fenParsed = V.ParseFen(fen);
167 // 1) Check position
168 if (!V.IsGoodPosition(fenParsed.position)) return false;
169 // 2) Check turn
170 if (!fenParsed.turn || !V.IsGoodTurn(fenParsed.turn)) return false;
171 // 3) Check moves count
172 if (!fenParsed.movesCount || !(parseInt(fenParsed.movesCount, 10) >= 0))
173 return false;
174 // 4) Check flags
175 if (V.HasFlags && (!fenParsed.flags || !V.IsGoodFlags(fenParsed.flags)))
176 return false;
177 // 5) Check enpassant
178 if (
179 V.HasEnpassant &&
180 (!fenParsed.enpassant || !V.IsGoodEnpassant(fenParsed.enpassant))
181 ) {
182 return false;
183 }
184 return true;
185 }
186
187 // Is position part of the FEN a priori correct?
188 static IsGoodPosition(position) {
189 if (position.length == 0) return false;
190 const rows = position.split("/");
191 if (rows.length != V.size.x) return false;
192 let kings = { "k": 0, "K": 0 };
193 for (let row of rows) {
194 let sumElts = 0;
195 for (let i = 0; i < row.length; i++) {
196 if (['K','k'].includes(row[i])) kings[row[i]]++;
197 if (V.PIECES.includes(row[i].toLowerCase())) sumElts++;
198 else {
199 const num = parseInt(row[i], 10);
200 if (isNaN(num) || num <= 0) return false;
201 sumElts += num;
202 }
203 }
204 if (sumElts != V.size.y) return false;
205 }
206 // Both kings should be on board. Exactly one per color.
207 if (Object.values(kings).some(v => v != 1)) return false;
208 return true;
209 }
210
211 // For FEN checking
212 static IsGoodTurn(turn) {
213 return ["w", "b"].includes(turn);
214 }
215
216 // For FEN checking
217 static IsGoodFlags(flags) {
218 // NOTE: a little too permissive to work with more variants
219 return !!flags.match(/^[a-z]{4,4}$/);
220 }
221
222 // NOTE: not with regexp to adapt to different board sizes. (TODO?)
223 static IsGoodEnpassant(enpassant) {
224 if (enpassant != "-") {
225 const ep = V.SquareToCoords(enpassant);
226 if (isNaN(ep.x) || !V.OnBoard(ep)) return false;
227 }
228 return true;
229 }
230
231 // 3 --> d (column number to letter)
232 static CoordToColumn(colnum) {
233 return String.fromCharCode(97 + colnum);
234 }
235
236 // d --> 3 (column letter to number)
237 static ColumnToCoord(column) {
238 return column.charCodeAt(0) - 97;
239 }
240
241 // a4 --> {x:3,y:0}
242 static SquareToCoords(sq) {
243 return {
244 // NOTE: column is always one char => max 26 columns
245 // row is counted from black side => subtraction
246 x: V.size.x - parseInt(sq.substr(1), 10),
247 y: sq[0].charCodeAt() - 97
248 };
249 }
250
251 // {x:0,y:4} --> e8
252 static CoordsToSquare(coords) {
253 return V.CoordToColumn(coords.y) + (V.size.x - coords.x);
254 }
255
256 // Path to pieces (standard ones in pieces/ folder)
257 getPpath(b) {
258 return b;
259 }
260
261 // Path to promotion pieces (usually the same)
262 getPPpath(m) {
263 return this.getPpath(m.appear[0].c + m.appear[0].p);
264 }
265
266 // Aggregates flags into one object
267 aggregateFlags() {
268 return this.castleFlags;
269 }
270
271 // Reverse operation
272 disaggregateFlags(flags) {
273 this.castleFlags = flags;
274 }
275
276 // En-passant square, if any
277 getEpSquare(moveOrSquare) {
278 if (!moveOrSquare) return undefined;
279 if (typeof moveOrSquare === "string") {
280 const square = moveOrSquare;
281 if (square == "-") return undefined;
282 return V.SquareToCoords(square);
283 }
284 // Argument is a move:
285 const move = moveOrSquare;
286 const s = move.start,
287 e = move.end;
288 if (
289 s.y == e.y &&
290 Math.abs(s.x - e.x) == 2 &&
291 // Next conditions for variants like Atomic or Rifle, Recycle...
292 (move.appear.length > 0 && move.appear[0].p == V.PAWN) &&
293 (move.vanish.length > 0 && move.vanish[0].p == V.PAWN)
294 ) {
295 return {
296 x: (s.x + e.x) / 2,
297 y: s.y
298 };
299 }
300 return undefined; //default
301 }
302
303 // Can thing on square1 take thing on square2
304 canTake([x1, y1], [x2, y2]) {
305 return this.getColor(x1, y1) !== this.getColor(x2, y2);
306 }
307
308 // Is (x,y) on the chessboard?
309 static OnBoard(x, y) {
310 return x >= 0 && x < V.size.x && y >= 0 && y < V.size.y;
311 }
312
313 // Used in interface: 'side' arg == player color
314 canIplay(side, [x, y]) {
315 return this.turn == side && this.getColor(x, y) == side;
316 }
317
318 // On which squares is color under check ? (for interface)
319 getCheckSquares() {
320 const color = this.turn;
321 return (
322 this.underCheck(color)
323 // kingPos must be duplicated, because it may change:
324 ? [JSON.parse(JSON.stringify(this.kingPos[color]))]
325 : []
326 );
327 }
328
329 /////////////
330 // FEN UTILS
331
332 // Setup the initial random (asymmetric) position
333 static GenRandInitFen(randomness) {
334 if (randomness == 0)
335 // Deterministic:
336 return "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w 0 ahah -";
337
338 let pieces = { w: new Array(8), b: new Array(8) };
339 let flags = "";
340 // Shuffle pieces on first (and last rank if randomness == 2)
341 for (let c of ["w", "b"]) {
342 if (c == 'b' && randomness == 1) {
343 pieces['b'] = pieces['w'];
344 flags += flags;
345 break;
346 }
347
348 let positions = ArrayFun.range(8);
349
350 // Get random squares for bishops
351 let randIndex = 2 * randInt(4);
352 const bishop1Pos = positions[randIndex];
353 // The second bishop must be on a square of different color
354 let randIndex_tmp = 2 * randInt(4) + 1;
355 const bishop2Pos = positions[randIndex_tmp];
356 // Remove chosen squares
357 positions.splice(Math.max(randIndex, randIndex_tmp), 1);
358 positions.splice(Math.min(randIndex, randIndex_tmp), 1);
359
360 // Get random squares for knights
361 randIndex = randInt(6);
362 const knight1Pos = positions[randIndex];
363 positions.splice(randIndex, 1);
364 randIndex = randInt(5);
365 const knight2Pos = positions[randIndex];
366 positions.splice(randIndex, 1);
367
368 // Get random square for queen
369 randIndex = randInt(4);
370 const queenPos = positions[randIndex];
371 positions.splice(randIndex, 1);
372
373 // Rooks and king positions are now fixed,
374 // because of the ordering rook-king-rook
375 const rook1Pos = positions[0];
376 const kingPos = positions[1];
377 const rook2Pos = positions[2];
378
379 // Finally put the shuffled pieces in the board array
380 pieces[c][rook1Pos] = "r";
381 pieces[c][knight1Pos] = "n";
382 pieces[c][bishop1Pos] = "b";
383 pieces[c][queenPos] = "q";
384 pieces[c][kingPos] = "k";
385 pieces[c][bishop2Pos] = "b";
386 pieces[c][knight2Pos] = "n";
387 pieces[c][rook2Pos] = "r";
388 flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos);
389 }
390 // Add turn + flags + enpassant
391 return (
392 pieces["b"].join("") +
393 "/pppppppp/8/8/8/8/PPPPPPPP/" +
394 pieces["w"].join("").toUpperCase() +
395 " w 0 " + flags + " -"
396 );
397 }
398
399 // "Parse" FEN: just return untransformed string data
400 static ParseFen(fen) {
401 const fenParts = fen.split(" ");
402 let res = {
403 position: fenParts[0],
404 turn: fenParts[1],
405 movesCount: fenParts[2]
406 };
407 let nextIdx = 3;
408 if (V.HasFlags) Object.assign(res, { flags: fenParts[nextIdx++] });
409 if (V.HasEnpassant) Object.assign(res, { enpassant: fenParts[nextIdx] });
410 return res;
411 }
412
413 // Return current fen (game state)
414 getFen() {
415 return (
416 this.getBaseFen() + " " +
417 this.getTurnFen() + " " +
418 this.movesCount +
419 (V.HasFlags ? " " + this.getFlagsFen() : "") +
420 (V.HasEnpassant ? " " + this.getEnpassantFen() : "")
421 );
422 }
423
424 getFenForRepeat() {
425 // Omit movesCount, only variable allowed to differ
426 return (
427 this.getBaseFen() + "_" +
428 this.getTurnFen() +
429 (V.HasFlags ? "_" + this.getFlagsFen() : "") +
430 (V.HasEnpassant ? "_" + this.getEnpassantFen() : "")
431 );
432 }
433
434 // Position part of the FEN string
435 getBaseFen() {
436 const format = (count) => {
437 // if more than 9 consecutive free spaces, break the integer,
438 // otherwise FEN parsing will fail.
439 if (count <= 9) return count;
440 // Currently only boards of size up to 11 or 12:
441 return "9" + (count - 9);
442 };
443 let position = "";
444 for (let i = 0; i < V.size.x; i++) {
445 let emptyCount = 0;
446 for (let j = 0; j < V.size.y; j++) {
447 if (this.board[i][j] == V.EMPTY) emptyCount++;
448 else {
449 if (emptyCount > 0) {
450 // Add empty squares in-between
451 position += format(emptyCount);
452 emptyCount = 0;
453 }
454 position += V.board2fen(this.board[i][j]);
455 }
456 }
457 if (emptyCount > 0) {
458 // "Flush remainder"
459 position += format(emptyCount);
460 }
461 if (i < V.size.x - 1) position += "/"; //separate rows
462 }
463 return position;
464 }
465
466 getTurnFen() {
467 return this.turn;
468 }
469
470 // Flags part of the FEN string
471 getFlagsFen() {
472 let flags = "";
473 // Castling flags
474 for (let c of ["w", "b"])
475 flags += this.castleFlags[c].map(V.CoordToColumn).join("");
476 return flags;
477 }
478
479 // Enpassant part of the FEN string
480 getEnpassantFen() {
481 const L = this.epSquares.length;
482 if (!this.epSquares[L - 1]) return "-"; //no en-passant
483 return V.CoordsToSquare(this.epSquares[L - 1]);
484 }
485
486 // Turn position fen into double array ["wb","wp","bk",...]
487 static GetBoard(position) {
488 const rows = position.split("/");
489 let board = ArrayFun.init(V.size.x, V.size.y, "");
490 for (let i = 0; i < rows.length; i++) {
491 let j = 0;
492 for (let indexInRow = 0; indexInRow < rows[i].length; indexInRow++) {
493 const character = rows[i][indexInRow];
494 const num = parseInt(character, 10);
495 // If num is a number, just shift j:
496 if (!isNaN(num)) j += num;
497 // Else: something at position i,j
498 else board[i][j++] = V.fen2board(character);
499 }
500 }
501 return board;
502 }
503
504 // Extract (relevant) flags from fen
505 setFlags(fenflags) {
506 // white a-castle, h-castle, black a-castle, h-castle
507 this.castleFlags = { w: [-1, -1], b: [-1, -1] };
508 for (let i = 0; i < 4; i++) {
509 this.castleFlags[i < 2 ? "w" : "b"][i % 2] =
510 V.ColumnToCoord(fenflags.charAt(i));
511 }
512 }
513
514 //////////////////
515 // INITIALIZATION
516
517 // Fen string fully describes the game state
518 constructor(fen) {
519 if (!fen)
520 // In printDiagram() fen isn't supply because only getPpath() is used
521 // TODO: find a better solution!
522 return;
523 const fenParsed = V.ParseFen(fen);
524 this.board = V.GetBoard(fenParsed.position);
525 this.turn = fenParsed.turn;
526 this.movesCount = parseInt(fenParsed.movesCount, 10);
527 this.setOtherVariables(fen);
528 }
529
530 // Scan board for kings positions
531 scanKings(fen) {
532 // Squares of white and black king:
533 this.kingPos = { w: [-1, -1], b: [-1, -1] };
534 const fenRows = V.ParseFen(fen).position.split("/");
535 const startRow = { 'w': V.size.x - 1, 'b': 0 };
536 for (let i = 0; i < fenRows.length; i++) {
537 let k = 0; //column index on board
538 for (let j = 0; j < fenRows[i].length; j++) {
539 switch (fenRows[i].charAt(j)) {
540 case "k":
541 this.kingPos["b"] = [i, k];
542 break;
543 case "K":
544 this.kingPos["w"] = [i, k];
545 break;
546 default: {
547 const num = parseInt(fenRows[i].charAt(j), 10);
548 if (!isNaN(num)) k += num - 1;
549 }
550 }
551 k++;
552 }
553 }
554 }
555
556 // Some additional variables from FEN (variant dependant)
557 setOtherVariables(fen) {
558 // Set flags and enpassant:
559 const parsedFen = V.ParseFen(fen);
560 if (V.HasFlags) this.setFlags(parsedFen.flags);
561 if (V.HasEnpassant) {
562 const epSq =
563 parsedFen.enpassant != "-"
564 ? this.getEpSquare(parsedFen.enpassant)
565 : undefined;
566 this.epSquares = [epSq];
567 }
568 // Search for kings positions:
569 this.scanKings(fen);
570 }
571
572 /////////////////////
573 // GETTERS & SETTERS
574
575 static get size() {
576 return { x: 8, y: 8 };
577 }
578
579 // Color of thing on square (i,j). 'undefined' if square is empty
580 getColor(i, j) {
581 return this.board[i][j].charAt(0);
582 }
583
584 // Piece type on square (i,j). 'undefined' if square is empty
585 getPiece(i, j) {
586 return this.board[i][j].charAt(1);
587 }
588
589 // Get opponent color
590 static GetOppCol(color) {
591 return color == "w" ? "b" : "w";
592 }
593
594 // Pieces codes (for a clearer code)
595 static get PAWN() {
596 return "p";
597 }
598 static get ROOK() {
599 return "r";
600 }
601 static get KNIGHT() {
602 return "n";
603 }
604 static get BISHOP() {
605 return "b";
606 }
607 static get QUEEN() {
608 return "q";
609 }
610 static get KING() {
611 return "k";
612 }
613
614 // For FEN checking:
615 static get PIECES() {
616 return [V.PAWN, V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN, V.KING];
617 }
618
619 // Empty square
620 static get EMPTY() {
621 return "";
622 }
623
624 // Some pieces movements
625 static get steps() {
626 return {
627 r: [
628 [-1, 0],
629 [1, 0],
630 [0, -1],
631 [0, 1]
632 ],
633 n: [
634 [-1, -2],
635 [-1, 2],
636 [1, -2],
637 [1, 2],
638 [-2, -1],
639 [-2, 1],
640 [2, -1],
641 [2, 1]
642 ],
643 b: [
644 [-1, -1],
645 [-1, 1],
646 [1, -1],
647 [1, 1]
648 ]
649 };
650 }
651
652 ////////////////////
653 // MOVES GENERATION
654
655 // All possible moves from selected square
656 getPotentialMovesFrom(sq) {
657 switch (this.getPiece(sq[0], sq[1])) {
658 case V.PAWN: return this.getPotentialPawnMoves(sq);
659 case V.ROOK: return this.getPotentialRookMoves(sq);
660 case V.KNIGHT: return this.getPotentialKnightMoves(sq);
661 case V.BISHOP: return this.getPotentialBishopMoves(sq);
662 case V.QUEEN: return this.getPotentialQueenMoves(sq);
663 case V.KING: return this.getPotentialKingMoves(sq);
664 }
665 return []; //never reached
666 }
667
668 // Build a regular move from its initial and destination squares.
669 // tr: transformation
670 getBasicMove([sx, sy], [ex, ey], tr) {
671 const initColor = this.getColor(sx, sy);
672 const initPiece = this.board[sx][sy].charAt(1);
673 let mv = new Move({
674 appear: [
675 new PiPo({
676 x: ex,
677 y: ey,
678 c: !!tr ? tr.c : initColor,
679 p: !!tr ? tr.p : initPiece
680 })
681 ],
682 vanish: [
683 new PiPo({
684 x: sx,
685 y: sy,
686 c: initColor,
687 p: initPiece
688 })
689 ]
690 });
691
692 // The opponent piece disappears if we take it
693 if (this.board[ex][ey] != V.EMPTY) {
694 mv.vanish.push(
695 new PiPo({
696 x: ex,
697 y: ey,
698 c: this.getColor(ex, ey),
699 p: this.board[ex][ey].charAt(1)
700 })
701 );
702 }
703
704 return mv;
705 }
706
707 // Generic method to find possible moves of non-pawn pieces:
708 // "sliding or jumping"
709 getSlideNJumpMoves([x, y], steps, oneStep) {
710 let moves = [];
711 outerLoop: for (let step of steps) {
712 let i = x + step[0];
713 let j = y + step[1];
714 while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
715 moves.push(this.getBasicMove([x, y], [i, j]));
716 if (oneStep) continue outerLoop;
717 i += step[0];
718 j += step[1];
719 }
720 if (V.OnBoard(i, j) && this.canTake([x, y], [i, j]))
721 moves.push(this.getBasicMove([x, y], [i, j]));
722 }
723 return moves;
724 }
725
726 // Special case of en-passant captures: treated separately
727 getEnpassantCaptures([x, y], shiftX) {
728 const Lep = this.epSquares.length;
729 const epSquare = this.epSquares[Lep - 1]; //always at least one element
730 let enpassantMove = null;
731 if (
732 !!epSquare &&
733 epSquare.x == x + shiftX &&
734 Math.abs(epSquare.y - y) == 1
735 ) {
736 enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]);
737 enpassantMove.vanish.push({
738 x: x,
739 y: epSquare.y,
740 p: this.board[x][epSquare.y].charAt(1),
741 c: this.getColor(x, epSquare.y)
742 });
743 }
744 return !!enpassantMove ? [enpassantMove] : [];
745 }
746
747 // Consider all potential promotions:
748 addPawnMoves([x1, y1], [x2, y2], moves, promotions) {
749 let finalPieces = [V.PAWN];
750 const color = this.turn; //this.getColor(x1, y1);
751 const lastRank = (color == "w" ? 0 : V.size.x - 1);
752 if (x2 == lastRank) {
753 // promotions arg: special override for Hiddenqueen variant
754 if (!!promotions) finalPieces = promotions;
755 else if (!!V.PawnSpecs.promotions) finalPieces = V.PawnSpecs.promotions;
756 }
757 let tr = null;
758 for (let piece of finalPieces) {
759 tr = (piece != V.PAWN ? { c: color, p: piece } : null);
760 moves.push(this.getBasicMove([x1, y1], [x2, y2], tr));
761 }
762 }
763
764 // What are the pawn moves from square x,y ?
765 getPotentialPawnMoves([x, y], promotions) {
766 const color = this.turn; //this.getColor(x, y);
767 const [sizeX, sizeY] = [V.size.x, V.size.y];
768 const pawnShiftX = V.PawnSpecs.directions[color];
769 const firstRank = (color == "w" ? sizeX - 1 : 0);
770 const forward = (color == 'w' ? -1 : 1);
771
772 // Pawn movements in shiftX direction:
773 const getPawnMoves = (shiftX) => {
774 let moves = [];
775 // NOTE: next condition is generally true (no pawn on last rank)
776 if (x + shiftX >= 0 && x + shiftX < sizeX) {
777 if (this.board[x + shiftX][y] == V.EMPTY) {
778 // One square forward (or backward)
779 this.addPawnMoves([x, y], [x + shiftX, y], moves, promotions);
780 // Next condition because pawns on 1st rank can generally jump
781 if (
782 V.PawnSpecs.twoSquares &&
783 (
784 (color == 'w' && x >= V.size.x - 1 - V.PawnSpecs.initShift['w'])
785 ||
786 (color == 'b' && x <= V.PawnSpecs.initShift['b'])
787 )
788 ) {
789 if (
790 shiftX == forward &&
791 this.board[x + 2 * shiftX][y] == V.EMPTY
792 ) {
793 // Two squares jump
794 moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
795 if (
796 V.PawnSpecs.threeSquares &&
797 this.board[x + 3 * shiftX][y] == V.EMPTY
798 ) {
799 // Three squares jump
800 moves.push(this.getBasicMove([x, y], [x + 3 * shiftX, y]));
801 }
802 }
803 }
804 }
805 // Captures
806 if (V.PawnSpecs.canCapture) {
807 for (let shiftY of [-1, 1]) {
808 if (y + shiftY >= 0 && y + shiftY < sizeY) {
809 if (
810 this.board[x + shiftX][y + shiftY] != V.EMPTY &&
811 this.canTake([x, y], [x + shiftX, y + shiftY])
812 ) {
813 this.addPawnMoves(
814 [x, y], [x + shiftX, y + shiftY],
815 moves, promotions
816 );
817 }
818 if (
819 V.PawnSpecs.captureBackward && shiftX == forward &&
820 x - shiftX >= 0 && x - shiftX < V.size.x &&
821 this.board[x - shiftX][y + shiftY] != V.EMPTY &&
822 this.canTake([x, y], [x - shiftX, y + shiftY])
823 ) {
824 this.addPawnMoves(
825 [x, y], [x - shiftX, y + shiftY],
826 moves, promotions
827 );
828 }
829 }
830 }
831 }
832 }
833 return moves;
834 }
835
836 let pMoves = getPawnMoves(pawnShiftX);
837 if (V.PawnSpecs.bidirectional)
838 pMoves = pMoves.concat(getPawnMoves(-pawnShiftX));
839
840 if (V.HasEnpassant) {
841 // NOTE: backward en-passant captures are not considered
842 // because no rules define them (for now).
843 Array.prototype.push.apply(
844 pMoves,
845 this.getEnpassantCaptures([x, y], pawnShiftX)
846 );
847 }
848
849 return pMoves;
850 }
851
852 // What are the rook moves from square x,y ?
853 getPotentialRookMoves(sq) {
854 return this.getSlideNJumpMoves(sq, V.steps[V.ROOK]);
855 }
856
857 // What are the knight moves from square x,y ?
858 getPotentialKnightMoves(sq) {
859 return this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep");
860 }
861
862 // What are the bishop moves from square x,y ?
863 getPotentialBishopMoves(sq) {
864 return this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]);
865 }
866
867 // What are the queen moves from square x,y ?
868 getPotentialQueenMoves(sq) {
869 return this.getSlideNJumpMoves(
870 sq,
871 V.steps[V.ROOK].concat(V.steps[V.BISHOP])
872 );
873 }
874
875 // What are the king moves from square x,y ?
876 getPotentialKingMoves(sq) {
877 // Initialize with normal moves
878 let moves = this.getSlideNJumpMoves(
879 sq,
880 V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
881 "oneStep"
882 );
883 if (V.HasCastle && this.castleFlags[this.turn].some(v => v < V.size.y))
884 moves = moves.concat(this.getCastleMoves(sq));
885 return moves;
886 }
887
888 // "castleInCheck" arg to let some variants castle under check
889 getCastleMoves([x, y], finalSquares, castleInCheck, castleWith) {
890 const c = this.getColor(x, y);
891
892 // Castling ?
893 const oppCol = V.GetOppCol(c);
894 let moves = [];
895 let i = 0;
896 // King, then rook:
897 finalSquares = finalSquares || [ [2, 3], [V.size.y - 2, V.size.y - 3] ];
898 const castlingKing = this.board[x][y].charAt(1);
899 castlingCheck: for (
900 let castleSide = 0;
901 castleSide < 2;
902 castleSide++ //large, then small
903 ) {
904 if (this.castleFlags[c][castleSide] >= V.size.y) continue;
905 // If this code is reached, rook and king are on initial position
906
907 // NOTE: in some variants this is not a rook
908 const rookPos = this.castleFlags[c][castleSide];
909 const castlingPiece = this.board[x][rookPos].charAt(1);
910 if (
911 this.board[x][rookPos] == V.EMPTY ||
912 this.getColor(x, rookPos) != c ||
913 (!!castleWith && !castleWith.includes(castlingPiece))
914 ) {
915 // Rook is not here, or changed color (see Benedict)
916 continue;
917 }
918
919 // Nothing on the path of the king ? (and no checks)
920 const finDist = finalSquares[castleSide][0] - y;
921 let step = finDist / Math.max(1, Math.abs(finDist));
922 i = y;
923 do {
924 if (
925 (!castleInCheck && this.isAttacked([x, i], oppCol)) ||
926 (
927 this.board[x][i] != V.EMPTY &&
928 // NOTE: next check is enough, because of chessboard constraints
929 (this.getColor(x, i) != c || ![y, rookPos].includes(i))
930 )
931 ) {
932 continue castlingCheck;
933 }
934 i += step;
935 } while (i != finalSquares[castleSide][0]);
936
937 // Nothing on the path to the rook?
938 step = castleSide == 0 ? -1 : 1;
939 for (i = y + step; i != rookPos; i += step) {
940 if (this.board[x][i] != V.EMPTY) continue castlingCheck;
941 }
942
943 // Nothing on final squares, except maybe king and castling rook?
944 for (i = 0; i < 2; i++) {
945 if (
946 finalSquares[castleSide][i] != rookPos &&
947 this.board[x][finalSquares[castleSide][i]] != V.EMPTY &&
948 (
949 finalSquares[castleSide][i] != y ||
950 this.getColor(x, finalSquares[castleSide][i]) != c
951 )
952 ) {
953 continue castlingCheck;
954 }
955 }
956
957 // If this code is reached, castle is valid
958 moves.push(
959 new Move({
960 appear: [
961 new PiPo({
962 x: x,
963 y: finalSquares[castleSide][0],
964 p: castlingKing,
965 c: c
966 }),
967 new PiPo({
968 x: x,
969 y: finalSquares[castleSide][1],
970 p: castlingPiece,
971 c: c
972 })
973 ],
974 vanish: [
975 // King might be initially disguised (Titan...)
976 new PiPo({ x: x, y: y, p: castlingKing, c: c }),
977 new PiPo({ x: x, y: rookPos, p: castlingPiece, c: c })
978 ],
979 end:
980 Math.abs(y - rookPos) <= 2
981 ? { x: x, y: rookPos }
982 : { x: x, y: y + 2 * (castleSide == 0 ? -1 : 1) }
983 })
984 );
985 }
986
987 return moves;
988 }
989
990 ////////////////////
991 // MOVES VALIDATION
992
993 // For the interface: possible moves for the current turn from square sq
994 getPossibleMovesFrom(sq) {
995 return this.filterValid(this.getPotentialMovesFrom(sq));
996 }
997
998 // TODO: promotions (into R,B,N,Q) should be filtered only once
999 filterValid(moves) {
1000 if (moves.length == 0) return [];
1001 const color = this.turn;
1002 return moves.filter(m => {
1003 this.play(m);
1004 const res = !this.underCheck(color);
1005 this.undo(m);
1006 return res;
1007 });
1008 }
1009
1010 getAllPotentialMoves() {
1011 const color = this.turn;
1012 let potentialMoves = [];
1013 for (let i = 0; i < V.size.x; i++) {
1014 for (let j = 0; j < V.size.y; j++) {
1015 if (this.board[i][j] != V.EMPTY && this.getColor(i, j) == color) {
1016 Array.prototype.push.apply(
1017 potentialMoves,
1018 this.getPotentialMovesFrom([i, j])
1019 );
1020 }
1021 }
1022 }
1023 return potentialMoves;
1024 }
1025
1026 // Search for all valid moves considering current turn
1027 // (for engine and game end)
1028 getAllValidMoves() {
1029 return this.filterValid(this.getAllPotentialMoves());
1030 }
1031
1032 // Stop at the first move found
1033 // TODO: not really, it explores all moves from a square (one is enough).
1034 atLeastOneMove() {
1035 const color = this.turn;
1036 for (let i = 0; i < V.size.x; i++) {
1037 for (let j = 0; j < V.size.y; j++) {
1038 if (this.board[i][j] != V.EMPTY && this.getColor(i, j) == color) {
1039 const moves = this.getPotentialMovesFrom([i, j]);
1040 if (moves.length > 0) {
1041 for (let k = 0; k < moves.length; k++)
1042 if (this.filterValid([moves[k]]).length > 0) return true;
1043 }
1044 }
1045 }
1046 }
1047 return false;
1048 }
1049
1050 // Check if pieces of given color are attacking (king) on square x,y
1051 isAttacked(sq, color) {
1052 return (
1053 this.isAttackedByPawn(sq, color) ||
1054 this.isAttackedByRook(sq, color) ||
1055 this.isAttackedByKnight(sq, color) ||
1056 this.isAttackedByBishop(sq, color) ||
1057 this.isAttackedByQueen(sq, color) ||
1058 this.isAttackedByKing(sq, color)
1059 );
1060 }
1061
1062 // Generic method for non-pawn pieces ("sliding or jumping"):
1063 // is x,y attacked by a piece of given color ?
1064 isAttackedBySlideNJump([x, y], color, piece, steps, oneStep) {
1065 for (let step of steps) {
1066 let rx = x + step[0],
1067 ry = y + step[1];
1068 while (V.OnBoard(rx, ry) && this.board[rx][ry] == V.EMPTY && !oneStep) {
1069 rx += step[0];
1070 ry += step[1];
1071 }
1072 if (
1073 V.OnBoard(rx, ry) &&
1074 this.getPiece(rx, ry) == piece &&
1075 this.getColor(rx, ry) == color
1076 ) {
1077 return true;
1078 }
1079 }
1080 return false;
1081 }
1082
1083 // Is square x,y attacked by 'color' pawns ?
1084 isAttackedByPawn(sq, color) {
1085 const pawnShift = (color == "w" ? 1 : -1);
1086 return this.isAttackedBySlideNJump(
1087 sq,
1088 color,
1089 V.PAWN,
1090 [[pawnShift, 1], [pawnShift, -1]],
1091 "oneStep"
1092 );
1093 }
1094
1095 // Is square x,y attacked by 'color' rooks ?
1096 isAttackedByRook(sq, color) {
1097 return this.isAttackedBySlideNJump(sq, color, V.ROOK, V.steps[V.ROOK]);
1098 }
1099
1100 // Is square x,y attacked by 'color' knights ?
1101 isAttackedByKnight(sq, color) {
1102 return this.isAttackedBySlideNJump(
1103 sq,
1104 color,
1105 V.KNIGHT,
1106 V.steps[V.KNIGHT],
1107 "oneStep"
1108 );
1109 }
1110
1111 // Is square x,y attacked by 'color' bishops ?
1112 isAttackedByBishop(sq, color) {
1113 return this.isAttackedBySlideNJump(sq, color, V.BISHOP, V.steps[V.BISHOP]);
1114 }
1115
1116 // Is square x,y attacked by 'color' queens ?
1117 isAttackedByQueen(sq, color) {
1118 return this.isAttackedBySlideNJump(
1119 sq,
1120 color,
1121 V.QUEEN,
1122 V.steps[V.ROOK].concat(V.steps[V.BISHOP])
1123 );
1124 }
1125
1126 // Is square x,y attacked by 'color' king(s) ?
1127 isAttackedByKing(sq, color) {
1128 return this.isAttackedBySlideNJump(
1129 sq,
1130 color,
1131 V.KING,
1132 V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
1133 "oneStep"
1134 );
1135 }
1136
1137 // Is color under check after his move ?
1138 underCheck(color) {
1139 return this.isAttacked(this.kingPos[color], V.GetOppCol(color));
1140 }
1141
1142 /////////////////
1143 // MOVES PLAYING
1144
1145 // Apply a move on board
1146 static PlayOnBoard(board, move) {
1147 for (let psq of move.vanish) board[psq.x][psq.y] = V.EMPTY;
1148 for (let psq of move.appear) board[psq.x][psq.y] = psq.c + psq.p;
1149 }
1150 // Un-apply the played move
1151 static UndoOnBoard(board, move) {
1152 for (let psq of move.appear) board[psq.x][psq.y] = V.EMPTY;
1153 for (let psq of move.vanish) board[psq.x][psq.y] = psq.c + psq.p;
1154 }
1155
1156 prePlay() {}
1157
1158 play(move) {
1159 // DEBUG:
1160// if (!this.states) this.states = [];
1161// const stateFen = this.getFen() + JSON.stringify(this.kingPos);
1162// this.states.push(stateFen);
1163
1164 this.prePlay(move);
1165 // Save flags (for undo)
1166 if (V.HasFlags) move.flags = JSON.stringify(this.aggregateFlags());
1167 if (V.HasEnpassant) this.epSquares.push(this.getEpSquare(move));
1168 V.PlayOnBoard(this.board, move);
1169 this.turn = V.GetOppCol(this.turn);
1170 this.movesCount++;
1171 this.postPlay(move);
1172 }
1173
1174 updateCastleFlags(move, piece, color) {
1175 const c = color || V.GetOppCol(this.turn);
1176 const firstRank = (c == "w" ? V.size.x - 1 : 0);
1177 // Update castling flags if rooks are moved
1178 const oppCol = this.turn;
1179 const oppFirstRank = V.size.x - 1 - firstRank;
1180 if (piece == V.KING && move.appear.length > 0)
1181 this.castleFlags[c] = [V.size.y, V.size.y];
1182 else if (
1183 move.start.x == firstRank && //our rook moves?
1184 this.castleFlags[c].includes(move.start.y)
1185 ) {
1186 const flagIdx = (move.start.y == this.castleFlags[c][0] ? 0 : 1);
1187 this.castleFlags[c][flagIdx] = V.size.y;
1188 }
1189 // NOTE: not "else if" because a rook could take an opposing rook
1190 if (
1191 move.end.x == oppFirstRank && //we took opponent rook?
1192 this.castleFlags[oppCol].includes(move.end.y)
1193 ) {
1194 const flagIdx = (move.end.y == this.castleFlags[oppCol][0] ? 0 : 1);
1195 this.castleFlags[oppCol][flagIdx] = V.size.y;
1196 }
1197 }
1198
1199 // After move is played, update variables + flags
1200 postPlay(move) {
1201 const c = V.GetOppCol(this.turn);
1202 let piece = undefined;
1203 if (move.vanish.length >= 1)
1204 // Usual case, something is moved
1205 piece = move.vanish[0].p;
1206 else
1207 // Crazyhouse-like variants
1208 piece = move.appear[0].p;
1209
1210 // Update king position + flags
1211 if (piece == V.KING && move.appear.length > 0)
1212 this.kingPos[c] = [move.appear[0].x, move.appear[0].y];
1213 if (V.HasCastle) this.updateCastleFlags(move, piece);
1214 }
1215
1216 preUndo() {}
1217
1218 undo(move) {
1219 this.preUndo(move);
1220 if (V.HasEnpassant) this.epSquares.pop();
1221 if (V.HasFlags) this.disaggregateFlags(JSON.parse(move.flags));
1222 V.UndoOnBoard(this.board, move);
1223 this.turn = V.GetOppCol(this.turn);
1224 this.movesCount--;
1225 this.postUndo(move);
1226
1227 // DEBUG:
1228// const stateFen = this.getFen() + JSON.stringify(this.kingPos);
1229// if (stateFen != this.states[this.states.length-1]) debugger;
1230// this.states.pop();
1231 }
1232
1233 // After move is undo-ed *and flags resetted*, un-update other variables
1234 // TODO: more symmetry, by storing flags increment in move (?!)
1235 postUndo(move) {
1236 // (Potentially) Reset king position
1237 const c = this.getColor(move.start.x, move.start.y);
1238 if (this.getPiece(move.start.x, move.start.y) == V.KING)
1239 this.kingPos[c] = [move.start.x, move.start.y];
1240 }
1241
1242 ///////////////
1243 // END OF GAME
1244
1245 // What is the score ? (Interesting if game is over)
1246 getCurrentScore() {
1247 if (this.atLeastOneMove()) return "*";
1248 // Game over
1249 const color = this.turn;
1250 // No valid move: stalemate or checkmate?
1251 if (!this.underCheck(color)) return "1/2";
1252 // OK, checkmate
1253 return (color == "w" ? "0-1" : "1-0");
1254 }
1255
1256 ///////////////
1257 // ENGINE PLAY
1258
1259 // Pieces values
1260 static get VALUES() {
1261 return {
1262 p: 1,
1263 r: 5,
1264 n: 3,
1265 b: 3,
1266 q: 9,
1267 k: 1000
1268 };
1269 }
1270
1271 // "Checkmate" (unreachable eval)
1272 static get INFINITY() {
1273 return 9999;
1274 }
1275
1276 // At this value or above, the game is over
1277 static get THRESHOLD_MATE() {
1278 return V.INFINITY;
1279 }
1280
1281 // Search depth: 1,2 for e.g. higher branching factor, 4 for smaller
1282 static get SEARCH_DEPTH() {
1283 return 3;
1284 }
1285
1286 // 'movesList' arg for some variants to provide a custom list
1287 getComputerMove(movesList) {
1288 const maxeval = V.INFINITY;
1289 const color = this.turn;
1290 let moves1 = movesList || this.getAllValidMoves();
1291
1292 if (moves1.length == 0)
1293 // TODO: this situation should not happen
1294 return null;
1295
1296 // Rank moves using a min-max at depth 2 (if search_depth >= 2!)
1297 for (let i = 0; i < moves1.length; i++) {
1298 this.play(moves1[i]);
1299 const score1 = this.getCurrentScore();
1300 if (score1 != "*") {
1301 moves1[i].eval =
1302 score1 == "1/2"
1303 ? 0
1304 : (score1 == "1-0" ? 1 : -1) * maxeval;
1305 }
1306 if (V.SEARCH_DEPTH == 1 || score1 != "*") {
1307 if (!moves1[i].eval) moves1[i].eval = this.evalPosition();
1308 this.undo(moves1[i]);
1309 continue;
1310 }
1311 // Initial self evaluation is very low: "I'm checkmated"
1312 moves1[i].eval = (color == "w" ? -1 : 1) * maxeval;
1313 // Initial enemy evaluation is very low too, for him
1314 let eval2 = (color == "w" ? 1 : -1) * maxeval;
1315 // Second half-move:
1316 let moves2 = this.getAllValidMoves();
1317 for (let j = 0; j < moves2.length; j++) {
1318 this.play(moves2[j]);
1319 const score2 = this.getCurrentScore();
1320 let evalPos = 0; //1/2 value
1321 switch (score2) {
1322 case "*":
1323 evalPos = this.evalPosition();
1324 break;
1325 case "1-0":
1326 evalPos = maxeval;
1327 break;
1328 case "0-1":
1329 evalPos = -maxeval;
1330 break;
1331 }
1332 if (
1333 (color == "w" && evalPos < eval2) ||
1334 (color == "b" && evalPos > eval2)
1335 ) {
1336 eval2 = evalPos;
1337 }
1338 this.undo(moves2[j]);
1339 }
1340 if (
1341 (color == "w" && eval2 > moves1[i].eval) ||
1342 (color == "b" && eval2 < moves1[i].eval)
1343 ) {
1344 moves1[i].eval = eval2;
1345 }
1346 this.undo(moves1[i]);
1347 }
1348 moves1.sort((a, b) => {
1349 return (color == "w" ? 1 : -1) * (b.eval - a.eval);
1350 });
1351// console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
1352
1353 // Skip depth 3+ if we found a checkmate (or if we are checkmated in 1...)
1354 if (V.SEARCH_DEPTH >= 3 && Math.abs(moves1[0].eval) < V.THRESHOLD_MATE) {
1355 for (let i = 0; i < moves1.length; i++) {
1356 this.play(moves1[i]);
1357 // 0.1 * oldEval : heuristic to avoid some bad moves (not all...)
1358 moves1[i].eval =
1359 0.1 * moves1[i].eval +
1360 this.alphabeta(V.SEARCH_DEPTH - 1, -maxeval, maxeval);
1361 this.undo(moves1[i]);
1362 }
1363 moves1.sort((a, b) => {
1364 return (color == "w" ? 1 : -1) * (b.eval - a.eval);
1365 });
1366 }
1367
1368 let candidates = [0];
1369 for (let i = 1; i < moves1.length && moves1[i].eval == moves1[0].eval; i++)
1370 candidates.push(i);
1371 return moves1[candidates[randInt(candidates.length)]];
1372 }
1373
1374 alphabeta(depth, alpha, beta) {
1375 const maxeval = V.INFINITY;
1376 const color = this.turn;
1377 const score = this.getCurrentScore();
1378 if (score != "*")
1379 return score == "1/2" ? 0 : (score == "1-0" ? 1 : -1) * maxeval;
1380 if (depth == 0) return this.evalPosition();
1381 const moves = this.getAllValidMoves();
1382 let v = color == "w" ? -maxeval : maxeval;
1383 if (color == "w") {
1384 for (let i = 0; i < moves.length; i++) {
1385 this.play(moves[i]);
1386 v = Math.max(v, this.alphabeta(depth - 1, alpha, beta));
1387 this.undo(moves[i]);
1388 alpha = Math.max(alpha, v);
1389 if (alpha >= beta) break; //beta cutoff
1390 }
1391 }
1392 else {
1393 // color=="b"
1394 for (let i = 0; i < moves.length; i++) {
1395 this.play(moves[i]);
1396 v = Math.min(v, this.alphabeta(depth - 1, alpha, beta));
1397 this.undo(moves[i]);
1398 beta = Math.min(beta, v);
1399 if (alpha >= beta) break; //alpha cutoff
1400 }
1401 }
1402 return v;
1403 }
1404
1405 evalPosition() {
1406 let evaluation = 0;
1407 // Just count material for now
1408 for (let i = 0; i < V.size.x; i++) {
1409 for (let j = 0; j < V.size.y; j++) {
1410 if (this.board[i][j] != V.EMPTY) {
1411 const sign = this.getColor(i, j) == "w" ? 1 : -1;
1412 evaluation += sign * V.VALUES[this.getPiece(i, j)];
1413 }
1414 }
1415 }
1416 return evaluation;
1417 }
1418
1419 /////////////////////////
1420 // MOVES + GAME NOTATION
1421 /////////////////////////
1422
1423 // Context: just before move is played, turn hasn't changed
1424 // TODO: un-ambiguous notation (switch on piece type, check directions...)
1425 getNotation(move) {
1426 if (move.appear.length == 2 && move.appear[0].p == V.KING)
1427 // Castle
1428 return move.end.y < move.start.y ? "0-0-0" : "0-0";
1429
1430 // Translate final square
1431 const finalSquare = V.CoordsToSquare(move.end);
1432
1433 const piece = this.getPiece(move.start.x, move.start.y);
1434 if (piece == V.PAWN) {
1435 // Pawn move
1436 let notation = "";
1437 if (move.vanish.length > move.appear.length) {
1438 // Capture
1439 const startColumn = V.CoordToColumn(move.start.y);
1440 notation = startColumn + "x" + finalSquare;
1441 }
1442 else notation = finalSquare;
1443 if (move.appear.length > 0 && move.appear[0].p != V.PAWN)
1444 // Promotion
1445 notation += "=" + move.appear[0].p.toUpperCase();
1446 return notation;
1447 }
1448 // Piece movement
1449 return (
1450 piece.toUpperCase() +
1451 (move.vanish.length > move.appear.length ? "x" : "") +
1452 finalSquare
1453 );
1454 }
1455
1456 static GetUnambiguousNotation(move) {
1457 // Machine-readable format with all the informations about the move
1458 return (
1459 (!!move.start && V.OnBoard(move.start.x, move.start.y)
1460 ? V.CoordsToSquare(move.start)
1461 : "-"
1462 ) + "." +
1463 (!!move.end && V.OnBoard(move.end.x, move.end.y)
1464 ? V.CoordsToSquare(move.end)
1465 : "-"
1466 ) + " " +
1467 (!!move.appear && move.appear.length > 0
1468 ? move.appear.map(a =>
1469 a.c + a.p + V.CoordsToSquare({ x: a.x, y: a.y })).join(".")
1470 : "-"
1471 ) + "/" +
1472 (!!move.vanish && move.vanish.length > 0
1473 ? move.vanish.map(a =>
1474 a.c + a.p + V.CoordsToSquare({ x: a.x, y: a.y })).join(".")
1475 : "-"
1476 )
1477 );
1478 }
1479
1480};