0996a70f54f967bba8504a2c7915d8a80c49f6f4
[xogo.git] / variants / Dynamo / class.js
1 import ChessRules from "/base_rules.js";
2
3 export default class DynamoRules extends ChessRules {
4
5 // TODO? later, allow to push out pawns on a and h files
6 get hasEnpassant() {
7 return false;
8 }
9
10 /// TODO:::
11
12 canIplay(side, [x, y]) {
13 // Sometimes opponent's pieces can be moved directly
14 return this.turn == side;
15 }
16
17 setOtherVariables(fen) {
18 super.setOtherVariables(fen);
19 this.subTurn = 1;
20 // Local stack of "action moves"
21 this.amoves = [];
22 const amove = V.ParseFen(fen).amove;
23 if (amove != "-") {
24 const amoveParts = amove.split("/");
25 let move = {
26 // No need for start & end
27 appear: [],
28 vanish: []
29 };
30 [0, 1].map(i => {
31 if (amoveParts[i] != "-") {
32 amoveParts[i].split(".").forEach(av => {
33 // Format is "bpe3"
34 const xy = V.SquareToCoords(av.substr(2));
35 move[i == 0 ? "appear" : "vanish"].push(
36 new PiPo({
37 x: xy.x,
38 y: xy.y,
39 c: av[0],
40 p: av[1]
41 })
42 );
43 });
44 }
45 });
46 this.amoves.push(move);
47 }
48 // Stack "first moves" (on subTurn 1) to merge and check opposite moves
49 this.firstMove = [];
50 }
51
52 static ParseFen(fen) {
53 return Object.assign(
54 ChessRules.ParseFen(fen),
55 { amove: fen.split(" ")[4] }
56 );
57 }
58
59 static IsGoodFen(fen) {
60 if (!ChessRules.IsGoodFen(fen)) return false;
61 const fenParts = fen.split(" ");
62 if (fenParts.length != 5) return false;
63 if (fenParts[4] != "-") {
64 // TODO: a single regexp instead.
65 // Format is [bpa2[.wpd3]] || '-'/[bbc3[.wrd5]] || '-'
66 const amoveParts = fenParts[4].split("/");
67 if (amoveParts.length != 2) return false;
68 for (let part of amoveParts) {
69 if (part != "-") {
70 for (let psq of part.split("."))
71 if (!psq.match(/^[a-z]{3}[1-8]$/)) return false;
72 }
73 }
74 }
75 return true;
76 }
77
78 getFen() {
79 return super.getFen() + " " + this.getAmoveFen();
80 }
81
82 getFenForRepeat() {
83 return super.getFenForRepeat() + "_" + this.getAmoveFen();
84 }
85
86 getAmoveFen() {
87 const L = this.amoves.length;
88 if (L == 0) return "-";
89 return (
90 ["appear","vanish"].map(
91 mpart => {
92 if (this.amoves[L-1][mpart].length == 0) return "-";
93 return (
94 this.amoves[L-1][mpart].map(
95 av => {
96 const square = V.CoordsToSquare({ x: av.x, y: av.y });
97 return av.c + av.p + square;
98 }
99 ).join(".")
100 );
101 }
102 ).join("/")
103 );
104 }
105
106 canTake() {
107 // Captures don't occur (only pulls & pushes)
108 return false;
109 }
110
111 // Step is right, just add (push/pull) moves in this direction
112 // Direction is assumed normalized.
113 getMovesInDirection([x, y], [dx, dy], nbSteps) {
114 nbSteps = nbSteps || 8; //max 8 steps anyway
115 let [i, j] = [x + dx, y + dy];
116 let moves = [];
117 const color = this.getColor(x, y);
118 const piece = this.getPiece(x, y);
119 const lastRank = (color == 'w' ? 0 : 7);
120 let counter = 1;
121 while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
122 if (i == lastRank && piece == V.PAWN) {
123 // Promotion by push or pull
124 V.PawnSpecs.promotions.forEach(p => {
125 let move = super.getBasicMove([x, y], [i, j], { c: color, p: p });
126 moves.push(move);
127 });
128 }
129 else moves.push(super.getBasicMove([x, y], [i, j]));
130 if (++counter > nbSteps) break;
131 i += dx;
132 j += dy;
133 }
134 if (!V.OnBoard(i, j) && piece != V.KING) {
135 // Add special "exit" move, by "taking king"
136 moves.push(
137 new Move({
138 start: { x: x, y: y },
139 end: { x: this.kingPos[color][0], y: this.kingPos[color][1] },
140 appear: [],
141 vanish: [{ x: x, y: y, c: color, p: piece }]
142 })
143 );
144 }
145 return moves;
146 }
147
148 // Normalize direction to know the step
149 getNormalizedDirection([dx, dy]) {
150 const absDir = [Math.abs(dx), Math.abs(dy)];
151 let divisor = 0;
152 if (absDir[0] != 0 && absDir[1] != 0 && absDir[0] != absDir[1])
153 // Knight
154 divisor = Math.min(absDir[0], absDir[1]);
155 else
156 // Standard slider (or maybe a pawn or king: same)
157 divisor = Math.max(absDir[0], absDir[1]);
158 return [dx / divisor, dy / divisor];
159 }
160
161 // There was something on x2,y2, maybe our color, pushed or (self)pulled
162 isAprioriValidExit([x1, y1], [x2, y2], color2, piece2) {
163 const color1 = this.getColor(x1, y1);
164 const pawnShift = (color1 == 'w' ? -1 : 1);
165 const lastRank = (color1 == 'w' ? 0 : 7);
166 const deltaX = Math.abs(x1 - x2);
167 const deltaY = Math.abs(y1 - y2);
168 const checkSlider = () => {
169 const dir = this.getNormalizedDirection([x2 - x1, y2 - y1]);
170 let [i, j] = [x1 + dir[0], y1 + dir[1]];
171 while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
172 i += dir[0];
173 j += dir[1];
174 }
175 return !V.OnBoard(i, j);
176 };
177 switch (piece2 || this.getPiece(x1, y1)) {
178 case V.PAWN:
179 return (
180 x1 + pawnShift == x2 &&
181 (
182 (color1 == color2 && x2 == lastRank && y1 == y2) ||
183 (
184 color1 != color2 &&
185 deltaY == 1 &&
186 !V.OnBoard(2 * x2 - x1, 2 * y2 - y1)
187 )
188 )
189 );
190 case V.ROOK:
191 if (x1 != x2 && y1 != y2) return false;
192 return checkSlider();
193 case V.KNIGHT:
194 return (
195 deltaX + deltaY == 3 &&
196 (deltaX == 1 || deltaY == 1) &&
197 !V.OnBoard(2 * x2 - x1, 2 * y2 - y1)
198 );
199 case V.BISHOP:
200 if (deltaX != deltaY) return false;
201 return checkSlider();
202 case V.QUEEN:
203 if (deltaX != 0 && deltaY != 0 && deltaX != deltaY) return false;
204 return checkSlider();
205 case V.KING:
206 return (
207 deltaX <= 1 &&
208 deltaY <= 1 &&
209 !V.OnBoard(2 * x2 - x1, 2 * y2 - y1)
210 );
211 }
212 return false;
213 }
214
215 isAprioriValidVertical([x1, y1], x2) {
216 const piece = this.getPiece(x1, y1);
217 const deltaX = Math.abs(x1 - x2);
218 const startRank = (this.getColor(x1, y1) == 'w' ? 6 : 1);
219 return (
220 [V.QUEEN, V.ROOK].includes(piece) ||
221 (
222 [V.KING, V.PAWN].includes(piece) &&
223 (
224 deltaX == 1 ||
225 (deltaX == 2 && piece == V.PAWN && x1 == startRank)
226 )
227 )
228 );
229 }
230
231 // NOTE: for pushes, play the pushed piece first.
232 // for pulls: play the piece doing the action first
233 // NOTE: to push a piece out of the board, make it slide until its king
234 getPotentialMovesFrom([x, y]) {
235 const color = this.turn;
236 const sqCol = this.getColor(x, y);
237 const pawnShift = (color == 'w' ? -1 : 1);
238 const pawnStartRank = (color == 'w' ? 6 : 1);
239 const getMoveHash = (m) => {
240 return V.CoordsToSquare(m.start) + V.CoordsToSquare(m.end);
241 };
242 if (this.subTurn == 1) {
243 const addMoves = (dir, nbSteps) => {
244 const newMoves =
245 this.getMovesInDirection([x, y], [-dir[0], -dir[1]], nbSteps)
246 .filter(m => !movesHash[getMoveHash(m)]);
247 newMoves.forEach(m => { movesHash[getMoveHash(m)] = true; });
248 Array.prototype.push.apply(moves, newMoves);
249 };
250 // Free to play any move (if piece of my color):
251 let moves =
252 sqCol == color
253 ? super.getPotentialMovesFrom([x, y])
254 : [];
255 // There may be several suicide moves: keep only one
256 let hasExit = false;
257 moves = moves.filter(m => {
258 const suicide = (m.appear.length == 0);
259 if (suicide) {
260 if (hasExit) return false;
261 hasExit = true;
262 }
263 return true;
264 });
265 // Structure to avoid adding moves twice (can be action & move)
266 let movesHash = {};
267 moves.forEach(m => { movesHash[getMoveHash(m)] = true; });
268 // [x, y] is pushed by 'color'
269 for (let step of V.steps[V.KNIGHT]) {
270 const [i, j] = [x + step[0], y + step[1]];
271 if (
272 V.OnBoard(i, j) &&
273 this.board[i][j] != V.EMPTY &&
274 this.getColor(i, j) == color &&
275 this.getPiece(i, j) == V.KNIGHT
276 ) {
277 addMoves(step, 1);
278 }
279 }
280 for (let step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) {
281 let [i, j] = [x + step[0], y + step[1]];
282 while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
283 i += step[0];
284 j += step[1];
285 }
286 if (
287 V.OnBoard(i, j) &&
288 this.board[i][j] != V.EMPTY &&
289 this.getColor(i, j) == color
290 ) {
291 const deltaX = Math.abs(i - x);
292 const deltaY = Math.abs(j - y);
293 switch (this.getPiece(i, j)) {
294 case V.PAWN:
295 if (
296 (x - i) / deltaX == pawnShift &&
297 deltaX <= 2 &&
298 deltaY <= 1
299 ) {
300 if (sqCol == color && deltaY == 0) {
301 // Pushed forward
302 const maxSteps = (i == pawnStartRank && deltaX == 1 ? 2 : 1);
303 addMoves(step, maxSteps);
304 }
305 else if (sqCol != color && deltaY == 1 && deltaX == 1)
306 // Pushed diagonally
307 addMoves(step, 1);
308 }
309 break;
310 case V.ROOK:
311 if (deltaX == 0 || deltaY == 0) addMoves(step);
312 break;
313 case V.BISHOP:
314 if (deltaX == deltaY) addMoves(step);
315 break;
316 case V.QUEEN:
317 // All steps are valid for a queen:
318 addMoves(step);
319 break;
320 case V.KING:
321 if (deltaX <= 1 && deltaY <= 1) addMoves(step, 1);
322 break;
323 }
324 }
325 }
326 return moves;
327 }
328 // If subTurn == 2 then we should have a first move,
329 // which restrict what we can play now: only in the first move direction
330 const L = this.firstMove.length;
331 const fm = this.firstMove[L-1];
332 if (
333 (fm.appear.length == 2 && fm.vanish.length == 2) ||
334 (fm.vanish[0].c == sqCol && sqCol != color)
335 ) {
336 // Castle or again opponent color: no move playable then.
337 return [];
338 }
339 const piece = this.getPiece(x, y);
340 const getPushExit = () => {
341 // Piece at subTurn 1 exited: can I have caused the exit?
342 if (
343 this.isAprioriValidExit(
344 [x, y],
345 [fm.start.x, fm.start.y],
346 fm.vanish[0].c
347 )
348 ) {
349 // Seems so:
350 const dir = this.getNormalizedDirection(
351 [fm.start.x - x, fm.start.y - y]);
352 const nbSteps =
353 [V.PAWN, V.KING, V.KNIGHT].includes(piece)
354 ? 1
355 : null;
356 return this.getMovesInDirection([x, y], dir, nbSteps);
357 }
358 return [];
359 }
360 const getPushMoves = () => {
361 // Piece from subTurn 1 is still on board:
362 const dirM = this.getNormalizedDirection(
363 [fm.end.x - fm.start.x, fm.end.y - fm.start.y]);
364 const dir = this.getNormalizedDirection(
365 [fm.start.x - x, fm.start.y - y]);
366 // Normalized directions should match
367 if (dir[0] == dirM[0] && dir[1] == dirM[1]) {
368 // We don't know if first move is a pushed piece or normal move,
369 // so still must check if the push is valid.
370 const deltaX = Math.abs(fm.start.x - x);
371 const deltaY = Math.abs(fm.start.y - y);
372 switch (piece) {
373 case V.PAWN:
374 if (x == pawnStartRank) {
375 if (
376 (fm.start.x - x) * pawnShift < 0 ||
377 deltaX >= 3 ||
378 deltaY >= 2 ||
379 (fm.vanish[0].c == color && deltaY > 0) ||
380 (fm.vanish[0].c != color && deltaY == 0) ||
381 Math.abs(fm.end.x - fm.start.x) > deltaX ||
382 fm.end.y - fm.start.y != fm.start.y - y
383 ) {
384 return [];
385 }
386 }
387 else {
388 if (
389 fm.start.x - x != pawnShift ||
390 deltaY >= 2 ||
391 (fm.vanish[0].c == color && deltaY == 1) ||
392 (fm.vanish[0].c != color && deltaY == 0) ||
393 fm.end.x - fm.start.x != pawnShift ||
394 fm.end.y - fm.start.y != fm.start.y - y
395 ) {
396 return [];
397 }
398 }
399 break;
400 case V.KNIGHT:
401 if (
402 (deltaX + deltaY != 3 || (deltaX == 0 && deltaY == 0)) ||
403 (fm.end.x - fm.start.x != fm.start.x - x) ||
404 (fm.end.y - fm.start.y != fm.start.y - y)
405 ) {
406 return [];
407 }
408 break;
409 case V.KING:
410 if (
411 (deltaX >= 2 || deltaY >= 2) ||
412 (fm.end.x - fm.start.x != fm.start.x - x) ||
413 (fm.end.y - fm.start.y != fm.start.y - y)
414 ) {
415 return [];
416 }
417 break;
418 case V.BISHOP:
419 if (deltaX != deltaY) return [];
420 break;
421 case V.ROOK:
422 if (deltaX != 0 && deltaY != 0) return [];
423 break;
424 case V.QUEEN:
425 if (deltaX != deltaY && deltaX != 0 && deltaY != 0) return [];
426 break;
427 }
428 // Nothing should stand between [x, y] and the square fm.start
429 let [i, j] = [x + dir[0], y + dir[1]];
430 while (
431 (i != fm.start.x || j != fm.start.y) &&
432 this.board[i][j] == V.EMPTY
433 ) {
434 i += dir[0];
435 j += dir[1];
436 }
437 if (i == fm.start.x && j == fm.start.y)
438 return this.getMovesInDirection([x, y], dir);
439 }
440 return [];
441 }
442 const getPullExit = () => {
443 // Piece at subTurn 1 exited: can I be pulled?
444 // Note: kings cannot suicide, so fm.vanish[0].p is not KING.
445 // Could be PAWN though, if a pawn was pushed out of board.
446 if (
447 fm.vanish[0].p != V.PAWN && //pawns cannot pull
448 this.isAprioriValidExit(
449 [x, y],
450 [fm.start.x, fm.start.y],
451 fm.vanish[0].c,
452 fm.vanish[0].p
453 )
454 ) {
455 // Seems so:
456 const dir = this.getNormalizedDirection(
457 [fm.start.x - x, fm.start.y - y]);
458 const nbSteps = (fm.vanish[0].p == V.KNIGHT ? 1 : null);
459 return this.getMovesInDirection([x, y], dir, nbSteps);
460 }
461 return [];
462 };
463 const getPullMoves = () => {
464 if (fm.vanish[0].p == V.PAWN)
465 // pawns cannot pull
466 return [];
467 const dirM = this.getNormalizedDirection(
468 [fm.end.x - fm.start.x, fm.end.y - fm.start.y]);
469 const dir = this.getNormalizedDirection(
470 [fm.start.x - x, fm.start.y - y]);
471 // Normalized directions should match
472 if (dir[0] == dirM[0] && dir[1] == dirM[1]) {
473 // Am I at the right distance?
474 const deltaX = Math.abs(x - fm.start.x);
475 const deltaY = Math.abs(y - fm.start.y);
476 if (
477 (fm.vanish[0].p == V.KING && (deltaX > 1 || deltaY > 1)) ||
478 (fm.vanish[0].p == V.KNIGHT &&
479 (deltaX + deltaY != 3 || deltaX == 0 || deltaY == 0))
480 ) {
481 return [];
482 }
483 // Nothing should stand between [x, y] and the square fm.start
484 let [i, j] = [x + dir[0], y + dir[1]];
485 while (
486 (i != fm.start.x || j != fm.start.y) &&
487 this.board[i][j] == V.EMPTY
488 ) {
489 i += dir[0];
490 j += dir[1];
491 }
492 if (i == fm.start.x && j == fm.start.y)
493 return this.getMovesInDirection([x, y], dir);
494 }
495 return [];
496 };
497 if (fm.vanish[0].c != color) {
498 // Only possible action is a push:
499 if (fm.appear.length == 0) return getPushExit();
500 return getPushMoves();
501 }
502 else if (sqCol != color) {
503 // Only possible action is a pull, considering moving piece abilities
504 if (fm.appear.length == 0) return getPullExit();
505 return getPullMoves();
506 }
507 else {
508 // My color + my color: both actions possible
509 // Structure to avoid adding moves twice (can be action & move)
510 let movesHash = {};
511 if (fm.appear.length == 0) {
512 const pushes = getPushExit();
513 pushes.forEach(m => { movesHash[getMoveHash(m)] = true; });
514 return (
515 pushes.concat(getPullExit().filter(m => !movesHash[getMoveHash(m)]))
516 );
517 }
518 const pushes = getPushMoves();
519 pushes.forEach(m => { movesHash[getMoveHash(m)] = true; });
520 return (
521 pushes.concat(getPullMoves().filter(m => !movesHash[getMoveHash(m)]))
522 );
523 }
524 return [];
525 }
526
527 getSlideNJumpMoves([x, y], steps, oneStep) {
528 let moves = [];
529 const c = this.getColor(x, y);
530 const piece = this.getPiece(x, y);
531 outerLoop: for (let step of steps) {
532 let i = x + step[0];
533 let j = y + step[1];
534 while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
535 moves.push(this.getBasicMove([x, y], [i, j]));
536 if (oneStep) continue outerLoop;
537 i += step[0];
538 j += step[1];
539 }
540 if (V.OnBoard(i, j)) {
541 if (this.canTake([x, y], [i, j]))
542 moves.push(this.getBasicMove([x, y], [i, j]));
543 }
544 else {
545 // Add potential board exit (suicide), except for the king
546 if (piece != V.KING) {
547 moves.push({
548 start: { x: x, y: y},
549 end: { x: this.kingPos[c][0], y: this.kingPos[c][1] },
550 appear: [],
551 vanish: [
552 new PiPo({
553 x: x,
554 y: y,
555 c: c,
556 p: piece
557 })
558 ]
559 });
560 }
561 }
562 }
563 return moves;
564 }
565
566 // Does m2 un-do m1 ? (to disallow undoing actions)
567 oppositeMoves(m1, m2) {
568 const isEqual = (av1, av2) => {
569 for (let av of av1) {
570 const avInAv2 = av2.find(elt => {
571 return (
572 elt.x == av.x &&
573 elt.y == av.y &&
574 elt.c == av.c &&
575 elt.p == av.p
576 );
577 });
578 if (!avInAv2) return false;
579 }
580 return true;
581 };
582 // All appear and vanish arrays must have the same length
583 const mL = m1.appear.length;
584 return (
585 m2.appear.length == mL &&
586 m1.vanish.length == mL &&
587 m2.vanish.length == mL &&
588 isEqual(m1.appear, m2.vanish) &&
589 isEqual(m1.vanish, m2.appear)
590 );
591 }
592
593 getAmove(move1, move2) {
594 // Just merge (one is action one is move, one may be empty)
595 return {
596 appear: move1.appear.concat(move2.appear),
597 vanish: move1.vanish.concat(move2.vanish)
598 }
599 }
600
601 filterValid(moves) {
602 const color = this.turn;
603 const La = this.amoves.length;
604 if (this.subTurn == 1) {
605 return moves.filter(m => {
606 // A move is valid either if it doesn't result in a check,
607 // or if a second move is possible to counter the check
608 // (not undoing a potential move + action of the opponent)
609 this.play(m);
610 let res = this.underCheck(color);
611 if (this.subTurn == 2) {
612 let isOpposite = La > 0 && this.oppositeMoves(this.amoves[La-1], m);
613 if (res || isOpposite) {
614 const moves2 = this.getAllPotentialMoves();
615 for (let m2 of moves2) {
616 this.play(m2);
617 const res2 = this.underCheck(color);
618 const amove = this.getAmove(m, m2);
619 isOpposite =
620 La > 0 && this.oppositeMoves(this.amoves[La-1], amove);
621 this.undo(m2);
622 if (!res2 && !isOpposite) {
623 res = false;
624 break;
625 }
626 }
627 }
628 }
629 this.undo(m);
630 return !res;
631 });
632 }
633 if (La == 0) return super.filterValid(moves);
634 const Lf = this.firstMove.length;
635 return (
636 super.filterValid(
637 moves.filter(m => {
638 // Move shouldn't undo another:
639 const amove = this.getAmove(this.firstMove[Lf-1], m);
640 return !this.oppositeMoves(this.amoves[La-1], amove);
641 })
642 )
643 );
644 }
645
646 isAttackedBySlideNJump([x, y], color, piece, steps, oneStep) {
647 for (let step of steps) {
648 let rx = x + step[0],
649 ry = y + step[1];
650 while (V.OnBoard(rx, ry) && this.board[rx][ry] == V.EMPTY && !oneStep) {
651 rx += step[0];
652 ry += step[1];
653 }
654 if (
655 V.OnBoard(rx, ry) &&
656 this.getPiece(rx, ry) == piece &&
657 this.getColor(rx, ry) == color
658 ) {
659 // Continue some steps in the same direction (pull)
660 rx += step[0];
661 ry += step[1];
662 while (
663 V.OnBoard(rx, ry) &&
664 this.board[rx][ry] == V.EMPTY &&
665 !oneStep
666 ) {
667 rx += step[0];
668 ry += step[1];
669 }
670 if (!V.OnBoard(rx, ry)) return true;
671 // Step in the other direction (push)
672 rx = x - step[0];
673 ry = y - step[1];
674 while (
675 V.OnBoard(rx, ry) &&
676 this.board[rx][ry] == V.EMPTY &&
677 !oneStep
678 ) {
679 rx -= step[0];
680 ry -= step[1];
681 }
682 if (!V.OnBoard(rx, ry)) return true;
683 }
684 }
685 return false;
686 }
687
688 isAttackedByPawn([x, y], color) {
689 // The king can be pushed out by a pawn on last rank or near the edge
690 const pawnShift = (color == "w" ? 1 : -1);
691 for (let i of [-1, 1]) {
692 if (
693 V.OnBoard(x + pawnShift, y + i) &&
694 this.board[x + pawnShift][y + i] != V.EMPTY &&
695 this.getPiece(x + pawnShift, y + i) == V.PAWN &&
696 this.getColor(x + pawnShift, y + i) == color
697 ) {
698 if (!V.OnBoard(x - pawnShift, y - i)) return true;
699 }
700 }
701 return false;
702 }
703
704 static OnTheEdge(x, y) {
705 return (x == 0 || x == 7 || y == 0 || y == 7);
706 }
707
708 isAttackedByKing([x, y], color) {
709 // Attacked if I'm on the edge and the opponent king just next,
710 // but not on the edge.
711 if (V.OnTheEdge(x, y)) {
712 for (let step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) {
713 const [i, j] = [x + step[0], y + step[1]];
714 if (
715 V.OnBoard(i, j) &&
716 !V.OnTheEdge(i, j) &&
717 this.board[i][j] != V.EMPTY &&
718 this.getPiece(i, j) == V.KING
719 // NOTE: since only one king of each color, and (x, y) is occupied
720 // by our king, no need to check other king's color.
721 ) {
722 return true;
723 }
724 }
725 }
726 return false;
727 }
728
729 // No consideration of color: all pieces could be played
730 getAllPotentialMoves() {
731 let potentialMoves = [];
732 for (let i = 0; i < V.size.x; i++) {
733 for (let j = 0; j < V.size.y; j++) {
734 if (this.board[i][j] != V.EMPTY) {
735 Array.prototype.push.apply(
736 potentialMoves,
737 this.getPotentialMovesFrom([i, j])
738 );
739 }
740 }
741 }
742 return potentialMoves;
743 }
744
745 getEmptyMove() {
746 return new Move({
747 start: { x: -1, y: -1 },
748 end: { x: -1, y: -1 },
749 appear: [],
750 vanish: []
751 });
752 }
753
754 doClick(square) {
755 // A click to promote a piece on subTurn 2 would trigger this.
756 // For now it would then return [NaN, NaN] because surrounding squares
757 // have no IDs in the promotion modal. TODO: improve this?
758 if (isNaN(square[0])) return null;
759 // If subTurn == 2 && square is empty && !underCheck && !isOpposite,
760 // then return an empty move, allowing to "pass" subTurn2
761 const La = this.amoves.length;
762 const Lf = this.firstMove.length;
763 if (
764 this.subTurn == 2 &&
765 this.board[square[0]][square[1]] == V.EMPTY &&
766 !this.underCheck(this.turn) &&
767 (La == 0 || !this.oppositeMoves(this.amoves[La-1], this.firstMove[Lf-1]))
768 ) {
769 return this.getEmptyMove();
770 }
771 return null;
772 }
773
774 play(move) {
775 if (this.subTurn == 1 && move.vanish.length == 0) {
776 // Patch to work with old format: (TODO: remove later)
777 move.ignore = true;
778 return;
779 }
780 const color = this.turn;
781 move.subTurn = this.subTurn; //for undo
782 const gotoNext = (mv) => {
783 const L = this.firstMove.length;
784 this.amoves.push(this.getAmove(this.firstMove[L-1], mv));
785 this.turn = V.GetOppCol(color);
786 this.subTurn = 1;
787 this.movesCount++;
788 };
789 move.flags = JSON.stringify(this.aggregateFlags());
790 V.PlayOnBoard(this.board, move);
791 if (this.subTurn == 2) gotoNext(move);
792 else {
793 this.subTurn = 2;
794 this.firstMove.push(move);
795 this.toNewKingPos(move);
796 if (
797 // Condition is true on empty arrays:
798 this.getAllPotentialMoves().every(m => {
799 V.PlayOnBoard(this.board, m);
800 this.toNewKingPos(m);
801 const res = this.underCheck(color);
802 V.UndoOnBoard(this.board, m);
803 this.toOldKingPos(m);
804 return res;
805 })
806 ) {
807 // No valid move at subTurn 2
808 gotoNext(this.getEmptyMove());
809 }
810 this.toOldKingPos(move);
811 }
812 this.postPlay(move);
813 }
814
815 toNewKingPos(move) {
816 for (let a of move.appear)
817 if (a.p == V.KING) this.kingPos[a.c] = [a.x, a.y];
818 }
819
820 postPlay(move) {
821 if (move.start.x < 0) return;
822 this.toNewKingPos(move);
823 this.updateCastleFlags(move);
824 }
825
826 updateCastleFlags(move) {
827 const firstRank = { 'w': V.size.x - 1, 'b': 0 };
828 for (let v of move.vanish) {
829 if (v.p == V.KING) this.castleFlags[v.c] = [V.size.y, V.size.y];
830 else if (v.x == firstRank[v.c] && this.castleFlags[v.c].includes(v.y)) {
831 const flagIdx = (v.y == this.castleFlags[v.c][0] ? 0 : 1);
832 this.castleFlags[v.c][flagIdx] = V.size.y;
833 }
834 }
835 }
836
837 undo(move) {
838 if (!!move.ignore) return; //TODO: remove that later
839 this.disaggregateFlags(JSON.parse(move.flags));
840 V.UndoOnBoard(this.board, move);
841 if (this.subTurn == 1) {
842 this.amoves.pop();
843 this.turn = V.GetOppCol(this.turn);
844 this.movesCount--;
845 }
846 if (move.subTurn == 1) this.firstMove.pop();
847 this.subTurn = move.subTurn;
848 this.toOldKingPos(move);
849 }
850
851 toOldKingPos(move) {
852 // (Potentially) Reset king position
853 for (let v of move.vanish)
854 if (v.p == V.KING) this.kingPos[v.c] = [v.x, v.y];
855 }
856
857 getComputerMove() {
858 let moves = this.getAllValidMoves();
859 if (moves.length == 0) return null;
860 // "Search" at depth 1 for now
861 const maxeval = V.INFINITY;
862 const color = this.turn;
863 const emptyMove = {
864 start: { x: -1, y: -1 },
865 end: { x: -1, y: -1 },
866 appear: [],
867 vanish: []
868 };
869 moves.forEach(m => {
870 this.play(m);
871 if (this.turn != color) m.eval = this.evalPosition();
872 else {
873 m.eval = (color == "w" ? -1 : 1) * maxeval;
874 const moves2 = this.getAllValidMoves().concat([emptyMove]);
875 m.next = moves2[0];
876 moves2.forEach(m2 => {
877 this.play(m2);
878 const score = this.getCurrentScore();
879 let mvEval = 0;
880 if (score != "1/2") {
881 if (score != "*") mvEval = (score == "1-0" ? 1 : -1) * maxeval;
882 else mvEval = this.evalPosition();
883 }
884 if (
885 (color == 'w' && mvEval > m.eval) ||
886 (color == 'b' && mvEval < m.eval)
887 ) {
888 m.eval = mvEval;
889 m.next = m2;
890 }
891 this.undo(m2);
892 });
893 }
894 this.undo(m);
895 });
896 moves.sort((a, b) => {
897 return (color == "w" ? 1 : -1) * (b.eval - a.eval);
898 });
899 let candidates = [0];
900 for (let i = 1; i < moves.length && moves[i].eval == moves[0].eval; i++)
901 candidates.push(i);
902 const mIdx = candidates[randInt(candidates.length)];
903 if (!moves[mIdx].next) return moves[mIdx];
904 const move2 = moves[mIdx].next;
905 delete moves[mIdx]["next"];
906 return [moves[mIdx], move2];
907 }
908
909 getNotation(move) {
910 if (move.start.x < 0)
911 // A second move is always required, but may be empty
912 return "-";
913 const initialSquare = V.CoordsToSquare(move.start);
914 const finalSquare = V.CoordsToSquare(move.end);
915 if (move.appear.length == 0)
916 // Pushed or pulled out of the board
917 return initialSquare + "R";
918 return move.appear[0].p.toUpperCase() + initialSquare + finalSquare;
919 }
920
921 };