Fix Synchrone2::filterValid()
[vchess.git] / client / src / variants / Synchrone1.js
1 import { ChessRules } from "@/base_rules";
2 import { randInt } from "@/utils/alea";
3
4 export class Synchrone1Rules extends ChessRules {
5
6 static get CanAnalyze() {
7 return false;
8 }
9
10 static get ShowMoves() {
11 return "byrow";
12 }
13
14 static get SomeHiddenMoves() {
15 return true;
16 }
17
18 static IsGoodFen(fen) {
19 if (!ChessRules.IsGoodFen(fen)) return false;
20 const fenParsed = V.ParseFen(fen);
21 // 5) Check whiteMove
22 if (
23 (
24 fenParsed.turn == "b" &&
25 // NOTE: do not check really JSON stringified move...
26 (!fenParsed.whiteMove || fenParsed.whiteMove == "-")
27 )
28 ||
29 (fenParsed.turn == "w" && fenParsed.whiteMove != "-")
30 ) {
31 return false;
32 }
33 return true;
34 }
35
36 static IsGoodEnpassant(enpassant) {
37 const epArray = enpassant.split(",");
38 if (![2, 3].includes(epArray.length)) return false;
39 epArray.forEach(epsq => {
40 if (epsq != "-") {
41 const ep = V.SquareToCoords(epsq);
42 if (isNaN(ep.x) || !V.OnBoard(ep)) return false;
43 }
44 });
45 return true;
46 }
47
48 static ParseFen(fen) {
49 const fenParts = fen.split(" ");
50 return Object.assign(
51 { whiteMove: fenParts[5] },
52 ChessRules.ParseFen(fen)
53 );
54 }
55
56 static GenRandInitFen(randomness) {
57 return ChessRules.GenRandInitFen(randomness).slice(0, -1) + "-,- -";
58 }
59
60 getFen() {
61 return super.getFen() + " " + this.getWhitemoveFen();
62 }
63
64 getFenForRepeat() {
65 return super.getFenForRepeat() + "_" + this.getWhitemoveFen();
66 }
67
68 setOtherVariables(fen) {
69 const parsedFen = V.ParseFen(fen);
70 this.setFlags(parsedFen.flags);
71 const epArray = parsedFen.enpassant.split(",");
72 this.epSquares = [];
73 epArray.forEach(epsq => this.epSquares.push(this.getEpSquare(epsq)));
74 this.scanKings();
75 // Also init whiteMove
76 this.whiteMove =
77 parsedFen.whiteMove != "-"
78 ? JSON.parse(parsedFen.whiteMove)
79 : null;
80 }
81
82 scanKings() {
83 this.kingPos = { w: [-1, -1], b: [-1, -1] };
84 for (let i = 0; i < V.size.x; i++) {
85 for (let j = 0; j < V.size.y; j++) {
86 if (this.getPiece(i, j) == V.KING)
87 this.kingPos[this.getColor(i, j)] = [i, j];
88 }
89 }
90 }
91
92 getEnpassantFen() {
93 const L = this.epSquares.length;
94 let res = "";
95 const start = L - 2 - (this.turn == 'b' ? 1 : 0);
96 for (let i=start; i < L; i++) {
97 if (!this.epSquares[i]) res += "-,";
98 else res += V.CoordsToSquare(this.epSquares[i]) + ",";
99 }
100 return res.slice(0, -1);
101 }
102
103 getWhitemoveFen() {
104 if (!this.whiteMove) return "-";
105 return JSON.stringify({
106 start: this.whiteMove.start,
107 end: this.whiteMove.end,
108 appear: this.whiteMove.appear,
109 vanish: this.whiteMove.vanish
110 });
111 }
112
113 getPossibleMovesFrom([x, y]) {
114 let moves = this.filterValid(super.getPotentialMovesFrom([x, y]));
115 if (!this.underCheck(this.getColor(x, y)))
116 // Augment with potential recaptures, except if we are under check
117 Array.prototype.push.apply(moves, this.getRecaptures([x, y]));
118 return moves;
119 }
120
121 // Aux function used to find opponent and self captures
122 getCaptures(from, to, color) {
123 const sliderAttack = (xx, yy, allowedSteps) => {
124 const deltaX = xx - to[0],
125 absDeltaX = Math.abs(deltaX);
126 const deltaY = yy - to[1],
127 absDeltaY = Math.abs(deltaY);
128 const step = [ deltaX / absDeltaX || 0, deltaY / absDeltaY || 0 ];
129 if (
130 // Check that the step is a priori valid:
131 (absDeltaX != absDeltaY && deltaX != 0 && deltaY != 0) ||
132 allowedSteps.every(st => st[0] != step[0] || st[1] != step[1])
133 ) {
134 return null;
135 }
136 let sq = [ to[0] + step[0], to[1] + step[1] ];
137 while (sq[0] != xx || sq[1] != yy) {
138 // NOTE: no need to check OnBoard in this special case
139 if (this.board[sq[0]][sq[1]] != V.EMPTY) return null;
140 sq[0] += step[0];
141 sq[1] += step[1];
142 }
143 return this.getBasicMove([xx, yy], [to[0], to[1]]);
144 };
145 // Can I take on the square 'to' ?
146 // If yes, return the (list of) capturing move(s)
147 const getTargetedCaptures = ([i, j]) => {
148 let move = null;
149 // From [i, j]:
150 switch (this.getPiece(i, j)) {
151 case V.PAWN: {
152 // Pushed pawns move as enemy pawns
153 const shift = (color == 'w' ? 1 : -1);
154 if (to[0] + shift == i && Math.abs(to[1] - j) == 1)
155 move = this.getBasicMove([i, j], to);
156 break;
157 }
158 case V.KNIGHT: {
159 const deltaX = Math.abs(i - to[0]);
160 const deltaY = Math.abs(j - to[1]);
161 if (
162 deltaX + deltaY == 3 &&
163 [1, 2].includes(deltaX) &&
164 [1, 2].includes(deltaY)
165 ) {
166 move = this.getBasicMove([i, j], to);
167 }
168 break;
169 }
170 case V.KING:
171 if (Math.abs(i - to[0]) <= 1 && Math.abs(j - to[1]) <= 1)
172 move = this.getBasicMove([i, j], to);
173 break;
174 case V.ROOK: {
175 move = sliderAttack(i, j, V.steps[V.ROOK]);
176 break;
177 }
178 case V.BISHOP: {
179 move = sliderAttack(i, j, V.steps[V.BISHOP]);
180 break;
181 }
182 case V.QUEEN: {
183 move = sliderAttack(i, j, V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
184 break;
185 }
186 }
187 return move;
188 };
189 let moves = [];
190 if (!!from) {
191 const theMove = getTargetedCaptures(from);
192 if (!!theMove) moves.push(theMove);
193 }
194 else {
195 for (let i=0; i<8; i++) {
196 for (let j=0; j<8; j++) {
197 if (this.getColor(i, j) == color) {
198 const newMove = getTargetedCaptures([i, j]);
199 if (!!newMove) moves.push(newMove);
200 }
201 }
202 }
203 }
204 return this.filterValid(moves);
205 }
206
207 getRecaptures(from) {
208 // 1) Generate all opponent's capturing moves
209 let oppCaptureMoves = [];
210 const color = this.turn;
211 const oppCol = V.GetOppCol(color);
212 for (let i=0; i<8; i++) {
213 for (let j=0; j<8; j++) {
214 if (
215 this.getColor(i, j) == color &&
216 // Do not consider king captures: self-captures of king are forbidden
217 this.getPiece(i, j) != V.KING
218 ) {
219 Array.prototype.push.apply(
220 oppCaptureMoves,
221 this.getCaptures(null, [i, j], oppCol)
222 );
223 }
224 }
225 }
226 // 2) Play each opponent's capture, and see if back-captures are possible:
227 // Lookup table to quickly decide if a move is already in list:
228 let moveSet = {};
229 let moves = [];
230 oppCaptureMoves.forEach(m => {
231 // If another opponent capture with same endpoint already processed, skip
232 const mHash = "m" + m.end.x + m.end.y;
233 if (!moveSet[mHash]) {
234 moveSet[mHash] = true;
235 // Just make enemy piece disappear, to clear potential path:
236 const justDisappear = {
237 appear: [],
238 vanish: [m.vanish[0]]
239 };
240 V.PlayOnBoard(this.board, justDisappear);
241 // Can I take on [m.end.x, m.end.y] ? If yes, add to list:
242 this.getCaptures(from, [m.end.x, m.end.y], color)
243 .forEach(cm => moves.push(cm));
244 V.UndoOnBoard(this.board, justDisappear);
245 }
246 });
247 return moves;
248 }
249
250 getAllValidMoves() {
251 // Return possible moves + potential recaptures
252 return super.getAllValidMoves().concat(this.getRecaptures());
253 }
254
255 filterValid(moves) {
256 if (moves.length == 0) return [];
257 // filterValid can be called when it's "not our turn":
258 const color = moves[0].vanish[0].c;
259 return moves.filter(m => {
260 const piece = m.vanish[0].p;
261 if (piece == V.KING) {
262 this.kingPos[color][0] = m.appear[0].x;
263 this.kingPos[color][1] = m.appear[0].y;
264 }
265 V.PlayOnBoard(this.board, m);
266 let res = !this.underCheck(color);
267 V.UndoOnBoard(this.board, m);
268 if (piece == V.KING) this.kingPos[color] = [m.start.x, m.start.y];
269 return res;
270 });
271 }
272
273 atLeastOneMove(color) {
274 const curTurn = this.turn;
275 this.turn = color;
276 const res = super.atLeastOneMove();
277 this.turn = curTurn;
278 return res;
279 }
280
281 // White and black (partial) moves were played: merge
282 resolveSynchroneMove(move) {
283 const m1 = this.whiteMove;
284 const m2 = move;
285 // For PlayOnBoard (no need for start / end, irrelevant)
286 let smove = {
287 appear: [],
288 vanish: [
289 m1.vanish[0],
290 m2.vanish[0]
291 ]
292 };
293 if ((m1.end.x != m2.end.x) || (m1.end.y != m2.end.y)) {
294 // Easy case: two independant moves (which may (self-)capture)
295 smove.appear.push(m1.appear[0]);
296 smove.appear.push(m2.appear[0]);
297 // "Captured" pieces may have moved:
298 if (m1.appear.length == 2) {
299 // Castle
300 smove.appear.push(m1.appear[1]);
301 smove.vanish.push(m1.vanish[1]);
302 }
303 else if (
304 m1.vanish.length == 2 &&
305 (
306 m1.vanish[1].x != m2.start.x ||
307 m1.vanish[1].y != m2.start.y
308 )
309 ) {
310 smove.vanish.push(m1.vanish[1]);
311 }
312 if (m2.appear.length == 2) {
313 // Castle
314 smove.appear.push(m2.appear[1]);
315 smove.vanish.push(m2.vanish[1]);
316 }
317 else if (
318 m2.vanish.length == 2 &&
319 (
320 m2.vanish[1].x != m1.start.x ||
321 m2.vanish[1].y != m1.start.y
322 )
323 ) {
324 smove.vanish.push(m2.vanish[1]);
325 }
326 }
327 else {
328 // Collision:
329 if (m1.vanish.length == 1 && m2.vanish.length == 1) {
330 // Easy case: both disappear except if one is a king
331 const p1 = m1.vanish[0].p;
332 const p2 = m2.vanish[0].p;
333 if ([p1, p2].includes(V.KING)) {
334 smove.appear.push({
335 x: m1.end.x,
336 y: m1.end.y,
337 p: V.KING,
338 c: (p1 == V.KING ? 'w' : 'b')
339 });
340 }
341 }
342 else {
343 // One move is a self-capture and the other a normal capture:
344 // only the self-capture appears
345 const selfCaptureMove =
346 m1.vanish[1].c == m1.vanish[0].c
347 ? m1
348 : m2;
349 smove.appear.push({
350 x: m1.end.x,
351 y: m1.end.y,
352 p: selfCaptureMove.appear[0].p,
353 c: selfCaptureMove.vanish[0].c
354 });
355 smove.vanish.push({
356 x: m1.end.x,
357 y: m1.end.y,
358 p: selfCaptureMove.vanish[1].p,
359 c: selfCaptureMove.vanish[0].c
360 });
361 }
362 }
363 return smove;
364 }
365
366 play(move) {
367 move.flags = JSON.stringify(this.aggregateFlags()); //save flags (for undo)
368 this.epSquares.push(this.getEpSquare(move));
369 // Do not play on board (would reveal the move...)
370 this.turn = V.GetOppCol(this.turn);
371 this.movesCount++;
372 this.postPlay(move);
373 }
374
375 updateCastleFlags(move) {
376 const firstRank = { 'w': V.size.x - 1, 'b': 0 };
377 move.appear.concat(move.vanish).forEach(av => {
378 for (let c of ['w', 'b']) {
379 if (av.x == firstRank[c] && this.castleFlags[c].includes(av.y)) {
380 const flagIdx = (av.y == this.castleFlags[c][0] ? 0 : 1);
381 this.castleFlags[c][flagIdx] = 8;
382 }
383 }
384 });
385 }
386
387 postPlay(move) {
388 if (this.turn == 'b') {
389 // NOTE: whiteMove is used read-only, so no need to copy
390 this.whiteMove = move;
391 return;
392 }
393
394 // A full turn just ended:
395 const smove = this.resolveSynchroneMove(move);
396 V.PlayOnBoard(this.board, smove);
397 move.whiteMove = this.whiteMove; //for undo
398 this.whiteMove = null;
399
400 // Update king position + flags
401 let kingAppear = { 'w': false, 'b': false };
402 for (let i = 0; i < smove.appear.length; i++) {
403 if (smove.appear[i].p == V.KING) {
404 const c = smove.appear[i].c;
405 kingAppear[c] = true;
406 this.kingPos[c][0] = smove.appear[i].x;
407 this.kingPos[c][1] = smove.appear[i].y;
408 }
409 }
410 for (let i = 0; i < smove.vanish.length; i++) {
411 if (smove.vanish[i].p == V.KING) {
412 const c = smove.vanish[i].c;
413 if (!kingAppear[c]) {
414 this.kingPos[c][0] = -1;
415 this.kingPos[c][1] = -1;
416 }
417 break;
418 }
419 }
420 this.updateCastleFlags(smove);
421 move.smove = smove;
422 }
423
424 undo(move) {
425 this.epSquares.pop();
426 this.disaggregateFlags(JSON.parse(move.flags));
427 if (this.turn == 'w')
428 // Back to the middle of the move
429 V.UndoOnBoard(this.board, move.smove);
430 this.turn = V.GetOppCol(this.turn);
431 this.movesCount--;
432 this.postUndo(move);
433 }
434
435 postUndo(move) {
436 if (this.turn == 'w') {
437 // Reset king positions: scan board (TODO: could be more efficient)
438 this.scanKings();
439 // Also reset whiteMove
440 this.whiteMove = null;
441 }
442 else this.whiteMove = move.whiteMove;
443 }
444
445 getCheckSquares() {
446 const color = this.turn;
447 if (color == 'b') {
448 // kingPos must be reset for appropriate highlighting:
449 var lastMove = JSON.parse(JSON.stringify(this.whiteMove));
450 this.undo(lastMove); //will erase whiteMove, thus saved above
451 }
452 let res = [];
453 if (this.kingPos['w'][0] >= 0 && this.underCheck('w'))
454 res.push(JSON.parse(JSON.stringify(this.kingPos['w'])));
455 if (this.kingPos['b'][0] >= 0 && this.underCheck('b'))
456 res.push(JSON.parse(JSON.stringify(this.kingPos['b'])));
457 if (color == 'b') this.play(lastMove);
458 return res;
459 }
460
461 getCurrentScore() {
462 if (this.turn == 'b')
463 // Turn (white + black) not over yet
464 return "*";
465 // Was a king captured?
466 if (this.kingPos['w'][0] < 0) return "0-1";
467 if (this.kingPos['b'][0] < 0) return "1-0";
468 const whiteCanMove = this.atLeastOneMove('w');
469 const blackCanMove = this.atLeastOneMove('b');
470 if (whiteCanMove && blackCanMove) return "*";
471 // Game over
472 const whiteInCheck = this.underCheck('w');
473 const blackInCheck = this.underCheck('b');
474 if (
475 (whiteCanMove && !this.underCheck('b')) ||
476 (blackCanMove && !this.underCheck('w'))
477 ) {
478 return "1/2";
479 }
480 // Checkmate: could be mutual
481 if (!whiteCanMove && !blackCanMove) return "1/2";
482 return (whiteCanMove ? "1-0" : "0-1");
483 }
484
485 getComputerMove() {
486 const maxeval = V.INFINITY;
487 const color = this.turn;
488 let moves = this.getAllValidMoves();
489 if (moves.length == 0)
490 // TODO: this situation should not happen
491 return null;
492
493 if (Math.random() < 0.5)
494 // Return a random move
495 return moves[randInt(moves.length)];
496
497 // Rank moves at depth 1:
498 // try to capture something (not re-capturing)
499 moves.forEach(m => {
500 V.PlayOnBoard(this.board, m);
501 m.eval = this.evalPosition();
502 V.UndoOnBoard(this.board, m);
503 });
504 moves.sort((a, b) => {
505 return (color == "w" ? 1 : -1) * (b.eval - a.eval);
506 });
507 let candidates = [0];
508 for (let i = 1; i < moves.length && moves[i].eval == moves[0].eval; i++)
509 candidates.push(i);
510 return moves[candidates[randInt(candidates.length)]];
511 }
512
513 getNotation(move) {
514 if (move.appear.length == 2 && move.appear[0].p == V.KING)
515 // Castle
516 return move.end.y < move.start.y ? "0-0-0" : "0-0";
517 // Basic system: piece + init + dest square
518 return (
519 move.vanish[0].p.toUpperCase() +
520 V.CoordsToSquare(move.start) +
521 V.CoordsToSquare(move.end)
522 );
523 }
524
525 };