Improve FEN length for Eightpieces variant
[vchess.git] / client / src / variants / Apocalypse.js
1 import { ChessRules } from "@/base_rules";
2 import { randInt } from "@/utils/alea";
3
4 export class ApocalypseRules extends ChessRules {
5 static get PawnSpecs() {
6 return Object.assign(
7 {},
8 ChessRules.PawnSpecs,
9 {
10 twoSquares: false,
11 promotions: [V.KNIGHT]
12 }
13 );
14 }
15
16 static get HasCastle() {
17 return false;
18 }
19
20 static get HasEnpassant() {
21 return false;
22 }
23
24 static get CanAnalyze() {
25 return false;
26 }
27
28 static get ShowMoves() {
29 return "byrow";
30 }
31
32 getPPpath(m) {
33 // Show the piece taken, if any, and not multiple pawns:
34 if (m.vanish.length == 1) return "Apocalypse/empty";
35 return m.vanish[1].c + m.vanish[1].p;
36 }
37
38 static get PIECES() {
39 return [V.PAWN, V.KNIGHT];
40 }
41
42 static IsGoodPosition(position) {
43 if (position.length == 0) return false;
44 const rows = position.split("/");
45 if (rows.length != V.size.x) return false;
46 // At least one pawn per color
47 let pawns = { "p": 0, "P": 0 };
48 for (let row of rows) {
49 let sumElts = 0;
50 for (let i = 0; i < row.length; i++) {
51 if (['P','p'].includes(row[i])) pawns[row[i]]++;
52 if (V.PIECES.includes(row[i].toLowerCase())) sumElts++;
53 else {
54 const num = parseInt(row[i]);
55 if (isNaN(num)) return false;
56 sumElts += num;
57 }
58 }
59 if (sumElts != V.size.y) return false;
60 }
61 if (Object.values(pawns).some(v => v == 0))
62 return false;
63 return true;
64 }
65
66 static IsGoodFen(fen) {
67 if (!ChessRules.IsGoodFen(fen)) return false;
68 const fenParsed = V.ParseFen(fen);
69 // 4) Check whiteMove
70 if (
71 (
72 fenParsed.turn == "b" &&
73 // NOTE: do not check really JSON stringified move...
74 (!fenParsed.whiteMove || fenParsed.whiteMove == "-")
75 )
76 ||
77 (fenParsed.turn == "w" && fenParsed.whiteMove != "-")
78 ) {
79 return false;
80 }
81 return true;
82 }
83
84 static IsGoodFlags(flags) {
85 return !!flags.match(/^[0-2]{2,2}$/);
86 }
87
88 aggregateFlags() {
89 return this.penaltyFlags;
90 }
91
92 disaggregateFlags(flags) {
93 this.penaltyFlags = flags;
94 }
95
96 static ParseFen(fen) {
97 const fenParts = fen.split(" ");
98 return Object.assign(
99 ChessRules.ParseFen(fen),
100 { whiteMove: fenParts[4] }
101 );
102 }
103
104 static get size() {
105 return { x: 5, y: 5 };
106 }
107
108 static GenRandInitFen() {
109 return "npppn/p3p/5/P3P/NPPPN w 0 00 -";
110 }
111
112 getFen() {
113 return super.getFen() + " " + this.getWhitemoveFen();
114 }
115
116 getFenForRepeat() {
117 return super.getFenForRepeat() + "_" + this.getWhitemoveFen();
118 }
119
120 getFlagsFen() {
121 return (
122 this.penaltyFlags['w'].toString() + this.penaltyFlags['b'].toString()
123 );
124 }
125
126 setOtherVariables(fen) {
127 const parsedFen = V.ParseFen(fen);
128 this.setFlags(parsedFen.flags);
129 // Also init whiteMove
130 this.whiteMove =
131 parsedFen.whiteMove != "-"
132 ? JSON.parse(parsedFen.whiteMove)
133 : null;
134 }
135
136 setFlags(fenflags) {
137 this.penaltyFlags = {
138 'w': parseInt(fenflags[0]),
139 'b': parseInt(fenflags[1])
140 };
141 }
142
143 getWhitemoveFen() {
144 if (!this.whiteMove) return "-";
145 return JSON.stringify({
146 start: this.whiteMove.start,
147 end: this.whiteMove.end,
148 appear: this.whiteMove.appear,
149 vanish: this.whiteMove.vanish,
150 illegal: this.whiteMove.illegal
151 });
152 }
153
154 getSpeculations(moves, sq) {
155 let moveSet = {};
156 moves.forEach(m => {
157 const mHash = "m" + m.start.x + m.start.y + m.end.x + m.end.y;
158 moveSet[mHash] = true;
159 });
160 const color = this.turn;
161 this.turn = V.GetOppCol(color);
162 const oppMoves = super.getAllValidMoves();
163 this.turn = color;
164 // For each opponent's move, generate valid moves [from sq if same color]
165 let speculations = [];
166 oppMoves.forEach(m => {
167 V.PlayOnBoard(this.board, m);
168 const newValidMoves =
169 !!sq
170 ? (
171 this.getColor(sq[0], sq[1]) == color
172 ? super.getPotentialMovesFrom(sq)
173 : []
174 )
175 : super.getAllValidMoves();
176 newValidMoves.forEach(vm => {
177 const mHash = "m" + vm.start.x + vm.start.y + vm.end.x + vm.end.y;
178 if (!moveSet[mHash]) {
179 moveSet[mHash] = true;
180 vm.illegal = true; //potentially illegal!
181 speculations.push(vm);
182 }
183 });
184 V.UndoOnBoard(this.board, m);
185 });
186 return speculations;
187 }
188
189 getPossibleMovesFrom([x, y]) {
190 const possibleMoves = super.getPotentialMovesFrom([x, y])
191 // Augment potential moves with opponent's moves speculation:
192 return possibleMoves.concat(this.getSpeculations(possibleMoves, [x, y]));
193 }
194
195 getAllValidMoves() {
196 // Return possible moves + potentially valid moves
197 const validMoves = super.getAllValidMoves();
198 return validMoves.concat(this.getSpeculations(validMoves));
199 }
200
201 addPawnMoves([x1, y1], [x2, y2], moves) {
202 let finalPieces = [V.PAWN];
203 const color = this.turn;
204 const lastRank = (color == "w" ? 0 : V.size.x - 1);
205 if (x2 == lastRank) {
206 // If 0 or 1 horsemen, promote in knight
207 let knightCounter = 0;
208 let emptySquares = [];
209 for (let i = 0; i < V.size.x; i++) {
210 for (let j = 0; j < V.size.y; j++) {
211 if (this.board[i][j] == V.EMPTY) emptySquares.push([i, j]);
212 else if (
213 this.getColor(i, j) == color &&
214 this.getPiece(i, j) == V.KNIGHT
215 ) {
216 knightCounter++;
217 }
218 }
219 }
220 if (knightCounter <= 1) finalPieces = [V.KNIGHT];
221 else {
222 // Generate all possible landings, maybe capturing something on the way
223 let capture = undefined;
224 if (this.board[x2][y2] != V.EMPTY) {
225 capture = JSON.parse(JSON.stringify({
226 x: x2,
227 y: y2,
228 c: this.getColor(x2, y2),
229 p: this.getPiece(x2, y2)
230 }));
231 }
232 emptySquares.forEach(sq => {
233 if (sq[0] != lastRank) {
234 let newMove = this.getBasicMove([x1, y1], [sq[0], sq[1]]);
235 if (!!capture) newMove.vanish.push(capture);
236 moves.push(newMove);
237 }
238 });
239 return;
240 }
241 }
242 let tr = null;
243 for (let piece of finalPieces) {
244 tr = (piece != V.PAWN ? { c: color, p: piece } : null);
245 moves.push(this.getBasicMove([x1, y1], [x2, y2], tr));
246 }
247 }
248
249 filterValid(moves) {
250 // No checks:
251 return moves;
252 }
253
254 atLeastOneMove(color) {
255 const curTurn = this.turn;
256 this.turn = color;
257 const res = super.atLeastOneMove();
258 this.turn = curTurn;
259 return res;
260 }
261
262 // White and black (partial) moves were played: merge
263 resolveSynchroneMove(move) {
264 let m1 = this.whiteMove;
265 let m2 = move;
266 const movingLikeCapture = (m) => {
267 const shift = (m.vanish[0].c == 'w' ? -1 : 1);
268 return (
269 m.start.x + shift == m.end.x &&
270 Math.abs(m.end.y - m.start.y) == 1
271 );
272 };
273 const isPossible = (m, other) => {
274 return (
275 (
276 m.vanish[0].p == V.KNIGHT &&
277 (
278 m.vanish.length == 1 ||
279 m.vanish[1].c != m.vanish[0].c ||
280 // Self-capture attempt
281 (
282 !other.illegal &&
283 other.end.x == m.end.x &&
284 other.end.y == m.end.y
285 )
286 )
287 )
288 ||
289 (
290 m.vanish[0].p == V.PAWN &&
291 !other.illegal &&
292 (
293 (
294 // Promotion attempt
295 m.end.x == (m.vanish[0].c == "w" ? 0 : V.size.x - 1) &&
296 other.vanish.length == 2 &&
297 other.vanish[1].p == V.KNIGHT &&
298 other.vanish[1].c == m.vanish[0].c
299 )
300 ||
301 (
302 // Moving attempt
303 !movingLikeCapture(m) &&
304 other.start.x == m.end.x &&
305 other.start.y == m.end.y
306 )
307 ||
308 (
309 // Capture attempt
310 movingLikeCapture(m) &&
311 other.end.x == m.end.x &&
312 other.end.y == m.end.y
313 )
314 )
315 )
316 );
317 };
318 if (!!m1.illegal && !isPossible(m1, m2)) {
319 // Either an anticipated capture of something which didn't move
320 // (or not to the right square), or a push through blocus.
321 // ==> Just discard the move, and add a penalty point
322 this.penaltyFlags[m1.vanish[0].c]++;
323 m1.isNull = true;
324 }
325 if (!!m2.illegal && !isPossible(m2, m1)) {
326 this.penaltyFlags[m2.vanish[0].c]++;
327 m2.isNull = true;
328 }
329 if (!!m1.isNull) m1 = null;
330 if (!!m2.isNull) m2 = null;
331 // If one move is illegal, just execute the other
332 if (!m1 && !!m2) return m2;
333 if (!m2 && !!m1) return m1;
334 // For PlayOnBoard (no need for start / end, irrelevant)
335 let smove = {
336 appear: [],
337 vanish: []
338 };
339 if (!m1 && !m2) return smove;
340 // Both moves are now legal or at least possible:
341 smove.vanish.push(m1.vanish[0]);
342 smove.vanish.push(m2.vanish[0]);
343 if ((m1.end.x != m2.end.x) || (m1.end.y != m2.end.y)) {
344 // Easy case: two independant moves
345 smove.appear.push(m1.appear[0]);
346 smove.appear.push(m2.appear[0]);
347 // "Captured" pieces may have moved:
348 if (
349 m1.vanish.length == 2 &&
350 (
351 m1.vanish[1].x != m2.start.x ||
352 m1.vanish[1].y != m2.start.y
353 )
354 ) {
355 smove.vanish.push(m1.vanish[1]);
356 }
357 if (
358 m2.vanish.length == 2 &&
359 (
360 m2.vanish[1].x != m1.start.x ||
361 m2.vanish[1].y != m1.start.y
362 )
363 ) {
364 smove.vanish.push(m2.vanish[1]);
365 }
366 } else {
367 // Collision: priority to the anticipated capture, if any.
368 // If ex-aequo: knight wins (higher risk), or both disappears.
369 // Then, priority to the knight vs pawn: remains.
370 // Finally: both disappears.
371 let remain = null;
372 const p1 = m1.vanish[0].p;
373 const p2 = m2.vanish[0].p;
374 if (!!m1.illegal && !m2.illegal) remain = { c: 'w', p: p1 };
375 else if (!!m2.illegal && !m1.illegal) remain = { c: 'b', p: p2 };
376 if (!remain) {
377 // Either both are illegal or both are legal
378 if (p1 == V.KNIGHT && p2 == V.PAWN) remain = { c: 'w', p: p1 };
379 else if (p2 == V.KNIGHT && p1 == V.PAWN) remain = { c: 'b', p: p2 };
380 // If remain is still null: same type same risk, both disappear
381 }
382 if (!!remain) {
383 smove.appear.push({
384 x: m1.end.x,
385 y: m1.end.y,
386 p: remain.p,
387 c: remain.c
388 });
389 }
390 }
391 return smove;
392 }
393
394 play(move) {
395 // Do not play on board (would reveal the move...)
396 move.flags = JSON.stringify(this.aggregateFlags());
397 this.turn = V.GetOppCol(this.turn);
398 this.movesCount++;
399 this.postPlay(move);
400 }
401
402 postPlay(move) {
403 if (this.turn == 'b') {
404 // NOTE: whiteMove is used read-only, so no need to copy
405 this.whiteMove = move;
406 return;
407 }
408 // A full turn just ended:
409 const smove = this.resolveSynchroneMove(move);
410 V.PlayOnBoard(this.board, smove);
411 move.whiteMove = this.whiteMove; //for undo
412 this.whiteMove = null;
413 move.smove = smove;
414 }
415
416 undo(move) {
417 this.disaggregateFlags(JSON.parse(move.flags));
418 if (this.turn == 'w')
419 // Back to the middle of the move
420 V.UndoOnBoard(this.board, move.smove);
421 this.turn = V.GetOppCol(this.turn);
422 this.movesCount--;
423 this.postUndo(move);
424 }
425
426 postUndo(move) {
427 if (this.turn == 'w') this.whiteMove = null;
428 else this.whiteMove = move.whiteMove;
429 }
430
431 getCheckSquares(color) {
432 return [];
433 }
434
435 getCurrentScore() {
436 if (this.turn == 'b')
437 // Turn (white + black) not over yet
438 return "*";
439 // Count footmen: if a side has none, it loses
440 let fmCount = { 'w': 0, 'b': 0 };
441 for (let i=0; i<5; i++) {
442 for (let j=0; j<5; j++) {
443 if (this.board[i][j] != V.EMPTY && this.getPiece(i, j) == V.PAWN)
444 fmCount[this.getColor(i, j)]++;
445 }
446 }
447 if (Object.values(fmCount).some(v => v == 0)) {
448 if (fmCount['w'] == 0 && fmCount['b'] == 0)
449 // Everyone died
450 return "1/2";
451 if (fmCount['w'] == 0) return "0-1";
452 return "1-0"; //fmCount['b'] == 0
453 }
454 // Check penaltyFlags: if a side has 2 or more, it loses
455 if (Object.values(this.penaltyFlags).every(v => v == 2)) return "1/2";
456 if (this.penaltyFlags['w'] == 2) return "0-1";
457 if (this.penaltyFlags['b'] == 2) return "1-0";
458 if (!this.atLeastOneMove('w') || !this.atLeastOneMove('b'))
459 // Stalemate (should be very rare)
460 return "1/2";
461 return "*";
462 }
463
464 getComputerMove() {
465 const maxeval = V.INFINITY;
466 const color = this.turn;
467 let moves = this.getAllValidMoves();
468 if (moves.length == 0)
469 // TODO: this situation should not happen
470 return null;
471
472 // Rank moves at depth 1:
473 let validMoves = [];
474 let illegalMoves = [];
475 moves.forEach(m => {
476 // Warning: m might be illegal!
477 if (!m.illegal) {
478 V.PlayOnBoard(this.board, m);
479 m.eval = this.evalPosition();
480 V.UndoOnBoard(this.board, m);
481 validMoves.push(m);
482 } else illegalMoves.push(m);
483 });
484
485 const illegalRatio = illegalMoves.length / moves.length;
486 if (Math.random() < illegalRatio)
487 // Return a random illegal move
488 return illegalMoves[randInt(illegalMoves.length)];
489
490 validMoves.sort((a, b) => {
491 return (color == "w" ? 1 : -1) * (b.eval - a.eval);
492 });
493 let candidates = [0];
494 for (
495 let i = 1;
496 i < validMoves.length && validMoves[i].eval == moves[0].eval;
497 i++
498 ) {
499 candidates.push(i);
500 }
501 return validMoves[candidates[randInt(candidates.length)]];
502 }
503
504 getNotation(move) {
505 // Basic system: piece + init + dest square
506 return (
507 (move.vanish[0].p == V.KNIGHT ? "N" : "") +
508 V.CoordsToSquare(move.start) +
509 V.CoordsToSquare(move.end)
510 );
511 }
512 };