Some fixes + work on Dynamo draft. Also listen for clicks in Board.vue
[vchess.git] / client / src / variants / Eightpieces.js
1 import { ArrayFun } from "@/utils/array";
2 import { randInt } from "@/utils/alea";
3 import { ChessRules, PiPo, Move } from "@/base_rules";
4
5 export class EightpiecesRules extends ChessRules {
6 static get JAILER() {
7 return "j";
8 }
9 static get SENTRY() {
10 return "s";
11 }
12 static get LANCER() {
13 return "l";
14 }
15
16 static get IMAGE_EXTENSION() {
17 // Temporarily, for the time SVG pieces are being designed:
18 return ".png";
19 }
20
21 // Lancer directions *from white perspective*
22 static get LANCER_DIRS() {
23 return {
24 'c': [-1, 0], //north
25 'd': [-1, 1], //N-E
26 'e': [0, 1], //east
27 'f': [1, 1], //S-E
28 'g': [1, 0], //south
29 'h': [1, -1], //S-W
30 'm': [0, -1], //west
31 'o': [-1, -1] //N-W
32 };
33 }
34
35 static get PIECES() {
36 return ChessRules.PIECES
37 .concat([V.JAILER, V.SENTRY])
38 .concat(Object.keys(V.LANCER_DIRS));
39 }
40
41 getPiece(i, j) {
42 const piece = this.board[i][j].charAt(1);
43 // Special lancer case: 8 possible orientations
44 if (Object.keys(V.LANCER_DIRS).includes(piece)) return V.LANCER;
45 return piece;
46 }
47
48 getPpath(b, color, score, orientation) {
49 if ([V.JAILER, V.SENTRY].includes(b[1])) return "Eightpieces/tmp_png/" + b;
50 if (Object.keys(V.LANCER_DIRS).includes(b[1])) {
51 if (orientation == 'w') return "Eightpieces/tmp_png/" + b;
52 // Find opposite direction for adequate display:
53 let oppDir = '';
54 switch (b[1]) {
55 case 'c':
56 oppDir = 'g';
57 break;
58 case 'g':
59 oppDir = 'c';
60 break;
61 case 'd':
62 oppDir = 'h';
63 break;
64 case 'h':
65 oppDir = 'd';
66 break;
67 case 'e':
68 oppDir = 'm';
69 break;
70 case 'm':
71 oppDir = 'e';
72 break;
73 case 'f':
74 oppDir = 'o';
75 break;
76 case 'o':
77 oppDir = 'f';
78 break;
79 }
80 return "Eightpieces/tmp_png/" + b[0] + oppDir;
81 }
82 // TODO: after we have SVG pieces, remove the folder and next prefix:
83 return "Eightpieces/tmp_png/" + b;
84 }
85
86 getPPpath(m, orientation) {
87 return (
88 this.getPpath(
89 m.appear[0].c + m.appear[0].p,
90 null,
91 null,
92 orientation
93 )
94 );
95 }
96
97 static ParseFen(fen) {
98 const fenParts = fen.split(" ");
99 return Object.assign(
100 ChessRules.ParseFen(fen),
101 { sentrypush: fenParts[5] }
102 );
103 }
104
105 static IsGoodFen(fen) {
106 if (!ChessRules.IsGoodFen(fen)) return false;
107 const fenParsed = V.ParseFen(fen);
108 // 5) Check sentry push (if any)
109 if (
110 fenParsed.sentrypush != "-" &&
111 !fenParsed.sentrypush.match(/^([a-h][1-8]){2,2}$/)
112 ) {
113 return false;
114 }
115 return true;
116 }
117
118 getFen() {
119 return super.getFen() + " " + this.getSentrypushFen();
120 }
121
122 getFenForRepeat() {
123 return super.getFenForRepeat() + "_" + this.getSentrypushFen();
124 }
125
126 getSentrypushFen() {
127 const L = this.sentryPush.length;
128 if (!this.sentryPush[L-1]) return "-";
129 let res = "";
130 const spL = this.sentryPush[L-1].length;
131 // Condensate path: just need initial and final squares:
132 return [0, spL - 1]
133 .map(i => V.CoordsToSquare(this.sentryPush[L-1][i]))
134 .join("");
135 }
136
137 setOtherVariables(fen) {
138 super.setOtherVariables(fen);
139 // subTurn == 2 only when a sentry moved, and is about to push something
140 this.subTurn = 1;
141 // Sentry position just after a "capture" (subTurn from 1 to 2)
142 this.sentryPos = null;
143 // Stack pieces' forbidden squares after a sentry move at each turn
144 const parsedFen = V.ParseFen(fen);
145 if (parsedFen.sentrypush == "-") this.sentryPush = [null];
146 else {
147 // Expand init + dest squares into a full path:
148 const init = V.SquareToCoords(parsedFen.sentrypush.substr(0, 2)),
149 dest = V.SquareToCoords(parsedFen.sentrypush.substr(2));
150 let newPath = [init];
151 const delta = ['x', 'y'].map(i => Math.abs(dest[i] - init[i]));
152 // Check that it's not a knight movement:
153 if (delta[0] == 0 || delta[1] == 0 || delta[0] == delta[1]) {
154 const step = ['x', 'y'].map((i, idx) => {
155 return (dest[i] - init[i]) / delta[idx] || 0
156 });
157 let x = init.x + step[0],
158 y = init.y + step[1];
159 while (x != dest.x || y != dest.y) {
160 newPath.push({ x: x, y: y });
161 x += step[0];
162 y += step[1];
163 }
164 }
165 newPath.push(dest);
166 this.sentryPush = [newPath];
167 }
168 }
169
170 static GenRandInitFen(randomness) {
171 if (randomness == 0)
172 // Deterministic:
173 return "jfsqkbnr/pppppppp/8/8/8/8/PPPPPPPP/JDSQKBNR w 0 ahah - -";
174
175 let pieces = { w: new Array(8), b: new Array(8) };
176 let flags = "";
177 // Shuffle pieces on first (and last rank if randomness == 2)
178 for (let c of ["w", "b"]) {
179 if (c == 'b' && randomness == 1) {
180 const lancerIdx = pieces['w'].findIndex(p => {
181 return Object.keys(V.LANCER_DIRS).includes(p);
182 });
183 pieces['b'] =
184 pieces['w'].slice(0, lancerIdx)
185 .concat(['g'])
186 .concat(pieces['w'].slice(lancerIdx + 1));
187 flags += flags;
188 break;
189 }
190
191 let positions = ArrayFun.range(8);
192
193 // Get random squares for bishop and sentry
194 let randIndex = 2 * randInt(4);
195 let bishopPos = positions[randIndex];
196 // The sentry must be on a square of different color
197 let randIndex_tmp = 2 * randInt(4) + 1;
198 let sentryPos = positions[randIndex_tmp];
199 if (c == 'b') {
200 // Check if white sentry is on the same color as ours.
201 // If yes: swap bishop and sentry positions.
202 // NOTE: test % 2 == 1 because there are 7 slashes.
203 if ((pieces['w'].indexOf('s') - sentryPos) % 2 == 1)
204 [bishopPos, sentryPos] = [sentryPos, bishopPos];
205 }
206 positions.splice(Math.max(randIndex, randIndex_tmp), 1);
207 positions.splice(Math.min(randIndex, randIndex_tmp), 1);
208
209 // Get random squares for knight and lancer
210 randIndex = randInt(6);
211 const knightPos = positions[randIndex];
212 positions.splice(randIndex, 1);
213 randIndex = randInt(5);
214 const lancerPos = positions[randIndex];
215 positions.splice(randIndex, 1);
216
217 // Get random square for queen
218 randIndex = randInt(4);
219 const queenPos = positions[randIndex];
220 positions.splice(randIndex, 1);
221
222 // Rook, jailer and king positions are now almost fixed,
223 // only the ordering rook->jailer or jailer->rook must be decided.
224 let rookPos = positions[0];
225 let jailerPos = positions[2];
226 const kingPos = positions[1];
227 flags += V.CoordToColumn(rookPos) + V.CoordToColumn(jailerPos);
228 if (Math.random() < 0.5) [rookPos, jailerPos] = [jailerPos, rookPos];
229
230 pieces[c][rookPos] = "r";
231 pieces[c][knightPos] = "n";
232 pieces[c][bishopPos] = "b";
233 pieces[c][queenPos] = "q";
234 pieces[c][kingPos] = "k";
235 pieces[c][sentryPos] = "s";
236 // Lancer faces north for white, and south for black:
237 pieces[c][lancerPos] = c == 'w' ? 'c' : 'g';
238 pieces[c][jailerPos] = "j";
239 }
240 return (
241 pieces["b"].join("") +
242 "/pppppppp/8/8/8/8/PPPPPPPP/" +
243 pieces["w"].join("").toUpperCase() +
244 " w 0 " + flags + " - -"
245 );
246 }
247
248 canTake([x1, y1], [x2, y2]) {
249 if (this.subTurn == 2)
250 // Only self captures on this subturn:
251 return this.getColor(x1, y1) == this.getColor(x2, y2);
252 return super.canTake([x1, y1], [x2, y2]);
253 }
254
255 // Is piece on square (x,y) immobilized?
256 isImmobilized([x, y]) {
257 const color = this.getColor(x, y);
258 const oppCol = V.GetOppCol(color);
259 for (let step of V.steps[V.ROOK]) {
260 const [i, j] = [x + step[0], y + step[1]];
261 if (
262 V.OnBoard(i, j) &&
263 this.board[i][j] != V.EMPTY &&
264 this.getColor(i, j) == oppCol
265 ) {
266 if (this.getPiece(i, j) == V.JAILER) return [i, j];
267 }
268 }
269 return null;
270 }
271
272 // Because of the lancers, getPiece() could be wrong:
273 // use board[x][y][1] instead (always valid).
274 getBasicMove([sx, sy], [ex, ey], tr) {
275 const initColor = this.getColor(sx, sy);
276 const initPiece = this.board[sx][sy].charAt(1);
277 let mv = new Move({
278 appear: [
279 new PiPo({
280 x: ex,
281 y: ey,
282 c: tr ? tr.c : initColor,
283 p: tr ? tr.p : initPiece
284 })
285 ],
286 vanish: [
287 new PiPo({
288 x: sx,
289 y: sy,
290 c: initColor,
291 p: initPiece
292 })
293 ]
294 });
295
296 // The opponent piece disappears if we take it
297 if (this.board[ex][ey] != V.EMPTY) {
298 mv.vanish.push(
299 new PiPo({
300 x: ex,
301 y: ey,
302 c: this.getColor(ex, ey),
303 p: this.board[ex][ey].charAt(1)
304 })
305 );
306 }
307
308 return mv;
309 }
310
311 canIplay(side, [x, y]) {
312 return (
313 (this.subTurn == 1 && this.turn == side && this.getColor(x, y) == side)
314 ||
315 (this.subTurn == 2 && x == this.sentryPos.x && y == this.sentryPos.y)
316 );
317 }
318
319 getPotentialMovesFrom([x, y]) {
320 // At subTurn == 2, jailers aren't effective (Jeff K)
321 const piece = this.getPiece(x, y);
322 const L = this.sentryPush.length;
323 if (this.subTurn == 1) {
324 const jsq = this.isImmobilized([x, y]);
325 if (!!jsq) {
326 let moves = [];
327 // Special pass move if king:
328 if (piece == V.KING) {
329 moves.push(
330 new Move({
331 appear: [],
332 vanish: [],
333 start: { x: x, y: y },
334 end: { x: jsq[0], y: jsq[1] }
335 })
336 );
337 }
338 else if (piece == V.LANCER && !!this.sentryPush[L-1]) {
339 // A pushed lancer next to the jailer: reorient
340 const color = this.getColor(x, y);
341 const curDir = this.board[x][y].charAt(1);
342 Object.keys(V.LANCER_DIRS).forEach(k => {
343 moves.push(
344 new Move({
345 appear: [{ x: x, y: y, c: color, p: k }],
346 vanish: [{ x: x, y: y, c: color, p: curDir }],
347 start: { x: x, y: y },
348 end: { x: jsq[0], y: jsq[1] }
349 })
350 );
351 });
352 }
353 return moves;
354 }
355 }
356 let moves = [];
357 switch (piece) {
358 case V.JAILER:
359 moves = this.getPotentialJailerMoves([x, y]);
360 break;
361 case V.SENTRY:
362 moves = this.getPotentialSentryMoves([x, y]);
363 break;
364 case V.LANCER:
365 moves = this.getPotentialLancerMoves([x, y]);
366 break;
367 default:
368 moves = super.getPotentialMovesFrom([x, y]);
369 break;
370 }
371 if (!!this.sentryPush[L-1]) {
372 // Delete moves walking back on sentry push path,
373 // only if not a pawn, and the piece is the pushed one.
374 const pl = this.sentryPush[L-1].length;
375 const finalPushedSq = this.sentryPush[L-1][pl-1];
376 moves = moves.filter(m => {
377 if (
378 m.vanish[0].p != V.PAWN &&
379 m.start.x == finalPushedSq.x && m.start.y == finalPushedSq.y &&
380 this.sentryPush[L-1].some(sq => sq.x == m.end.x && sq.y == m.end.y)
381 ) {
382 return false;
383 }
384 return true;
385 });
386 } else if (this.subTurn == 2) {
387 // Put back the sentinel on board:
388 const color = this.turn;
389 moves.forEach(m => {
390 m.appear.push({x: x, y: y, p: V.SENTRY, c: color});
391 });
392 }
393 return moves;
394 }
395
396 getPotentialPawnMoves([x, y]) {
397 const color = this.getColor(x, y);
398 let moves = [];
399 const [sizeX, sizeY] = [V.size.x, V.size.y];
400 let shiftX = (color == "w" ? -1 : 1);
401 if (this.subTurn == 2) shiftX *= -1;
402 const firstRank = color == "w" ? sizeX - 1 : 0;
403 const startRank = color == "w" ? sizeX - 2 : 1;
404 const lastRank = color == "w" ? 0 : sizeX - 1;
405
406 // Pawns might be pushed on 1st rank and attempt to move again:
407 if (!V.OnBoard(x + shiftX, y)) return [];
408
409 const finalPieces =
410 // A push cannot put a pawn on last rank (it goes backward)
411 x + shiftX == lastRank
412 ? Object.keys(V.LANCER_DIRS).concat(
413 [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN, V.SENTRY, V.JAILER])
414 : [V.PAWN];
415 if (this.board[x + shiftX][y] == V.EMPTY) {
416 // One square forward
417 for (let piece of finalPieces) {
418 moves.push(
419 this.getBasicMove([x, y], [x + shiftX, y], {
420 c: color,
421 p: piece
422 })
423 );
424 }
425 if (
426 // 2-squares jumps forbidden if pawn push
427 this.subTurn == 1 &&
428 [startRank, firstRank].includes(x) &&
429 this.board[x + 2 * shiftX][y] == V.EMPTY
430 ) {
431 // Two squares jump
432 moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
433 }
434 }
435 // Captures
436 for (let shiftY of [-1, 1]) {
437 if (
438 y + shiftY >= 0 &&
439 y + shiftY < sizeY &&
440 this.board[x + shiftX][y + shiftY] != V.EMPTY &&
441 this.canTake([x, y], [x + shiftX, y + shiftY])
442 ) {
443 for (let piece of finalPieces) {
444 moves.push(
445 this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
446 c: color,
447 p: piece
448 })
449 );
450 }
451 }
452 }
453
454 // En passant: only on subTurn == 1
455 const Lep = this.epSquares.length;
456 const epSquare = this.epSquares[Lep - 1];
457 if (
458 this.subTurn == 1 &&
459 !!epSquare &&
460 epSquare.x == x + shiftX &&
461 Math.abs(epSquare.y - y) == 1
462 ) {
463 let enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]);
464 enpassantMove.vanish.push({
465 x: x,
466 y: epSquare.y,
467 p: "p",
468 c: this.getColor(x, epSquare.y)
469 });
470 moves.push(enpassantMove);
471 }
472
473 return moves;
474 }
475
476 // Obtain all lancer moves in "step" direction
477 getPotentialLancerMoves_aux([x, y], step, tr) {
478 let moves = [];
479 // Add all moves to vacant squares until opponent is met:
480 const color = this.getColor(x, y);
481 const oppCol =
482 this.subTurn == 1
483 ? V.GetOppCol(color)
484 // at subTurn == 2, consider own pieces as opponent
485 : color;
486 let sq = [x + step[0], y + step[1]];
487 while (V.OnBoard(sq[0], sq[1]) && this.getColor(sq[0], sq[1]) != oppCol) {
488 if (this.board[sq[0]][sq[1]] == V.EMPTY)
489 moves.push(this.getBasicMove([x, y], sq, tr));
490 sq[0] += step[0];
491 sq[1] += step[1];
492 }
493 if (V.OnBoard(sq[0], sq[1]))
494 // Add capturing move
495 moves.push(this.getBasicMove([x, y], sq, tr));
496 return moves;
497 }
498
499 getPotentialLancerMoves([x, y]) {
500 let moves = [];
501 // Add all lancer possible orientations, similar to pawn promotions.
502 // Except if just after a push: allow all movements from init square then
503 const L = this.sentryPush.length;
504 const color = this.getColor(x, y);
505 if (!!this.sentryPush[L-1]) {
506 // Maybe I was pushed
507 const pl = this.sentryPush[L-1].length;
508 if (
509 this.sentryPush[L-1][pl-1].x == x &&
510 this.sentryPush[L-1][pl-1].y == y
511 ) {
512 // I was pushed: allow all directions (for this move only), but
513 // do not change direction after moving, *except* if I keep the
514 // same orientation in which I was pushed.
515 const curDir = V.LANCER_DIRS[this.board[x][y].charAt(1)];
516 Object.values(V.LANCER_DIRS).forEach(step => {
517 const dirCode = Object.keys(V.LANCER_DIRS).find(k => {
518 return (
519 V.LANCER_DIRS[k][0] == step[0] &&
520 V.LANCER_DIRS[k][1] == step[1]
521 );
522 });
523 const dirMoves =
524 this.getPotentialLancerMoves_aux(
525 [x, y],
526 step,
527 { p: dirCode, c: color }
528 );
529 if (curDir[0] == step[0] && curDir[1] == step[1]) {
530 // Keeping same orientation: can choose after
531 let chooseMoves = [];
532 dirMoves.forEach(m => {
533 Object.keys(V.LANCER_DIRS).forEach(k => {
534 let mk = JSON.parse(JSON.stringify(m));
535 mk.appear[0].p = k;
536 moves.push(mk);
537 });
538 });
539 Array.prototype.push.apply(moves, chooseMoves);
540 } else Array.prototype.push.apply(moves, dirMoves);
541 });
542 return moves;
543 }
544 }
545 // I wasn't pushed: standard lancer move
546 const dirCode = this.board[x][y][1];
547 const monodirMoves =
548 this.getPotentialLancerMoves_aux([x, y], V.LANCER_DIRS[dirCode]);
549 // Add all possible orientations aftermove except if I'm being pushed
550 if (this.subTurn == 1) {
551 monodirMoves.forEach(m => {
552 Object.keys(V.LANCER_DIRS).forEach(k => {
553 let mk = JSON.parse(JSON.stringify(m));
554 mk.appear[0].p = k;
555 moves.push(mk);
556 });
557 });
558 return moves;
559 } else {
560 // I'm pushed: add potential nudges
561 let potentialNudges = [];
562 for (let step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) {
563 if (
564 V.OnBoard(x + step[0], y + step[1]) &&
565 this.board[x + step[0]][y + step[1]] == V.EMPTY
566 ) {
567 const newDirCode = Object.keys(V.LANCER_DIRS).find(k => {
568 const codeStep = V.LANCER_DIRS[k];
569 return (codeStep[0] == step[0] && codeStep[1] == step[1]);
570 });
571 potentialNudges.push(
572 this.getBasicMove(
573 [x, y],
574 [x + step[0], y + step[1]],
575 { c: color, p: newDirCode }
576 )
577 );
578 }
579 }
580 return monodirMoves.concat(potentialNudges);
581 }
582 }
583
584 getPotentialSentryMoves([x, y]) {
585 // The sentry moves a priori like a bishop:
586 let moves = super.getPotentialBishopMoves([x, y]);
587 // ...but captures are replaced by special move, if and only if
588 // "captured" piece can move now, considered as the capturer unit.
589 // --> except is subTurn == 2, in this case I don't push anything.
590 if (this.subTurn == 2) return moves.filter(m => m.vanish.length == 1);
591 moves.forEach(m => {
592 if (m.vanish.length == 2) {
593 // Temporarily cancel the sentry capture:
594 m.appear.pop();
595 m.vanish.pop();
596 }
597 });
598 const color = this.getColor(x, y);
599 const fMoves = moves.filter(m => {
600 // Can the pushed unit make any move? ...resulting in a non-self-check?
601 if (m.appear.length == 0) {
602 let res = false;
603 this.play(m);
604 let moves2 = this.getPotentialMovesFrom([m.end.x, m.end.y]);
605 for (let m2 of moves2) {
606 this.play(m2);
607 res = !this.underCheck(color);
608 this.undo(m2);
609 if (res) break;
610 }
611 this.undo(m);
612 return res;
613 }
614 return true;
615 });
616 return fMoves;
617 }
618
619 getPotentialJailerMoves([x, y]) {
620 return super.getPotentialRookMoves([x, y]).filter(m => {
621 // Remove jailer captures
622 return m.vanish[0].p != V.JAILER || m.vanish.length == 1;
623 });
624 }
625
626 getPotentialKingMoves(sq) {
627 const moves = this.getSlideNJumpMoves(
628 sq,
629 V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
630 "oneStep"
631 );
632 return (
633 this.subTurn == 1
634 ? moves.concat(this.getCastleMoves(sq))
635 : moves
636 );
637 }
638
639 atLeastOneMove() {
640 // If in second-half of a move, we already know that a move is possible
641 if (this.subTurn == 2) return true;
642 return super.atLeastOneMove();
643 }
644
645 filterValid(moves) {
646 if (moves.length == 0) return [];
647 const basicFilter = (m, c) => {
648 this.play(m);
649 const res = !this.underCheck(c);
650 this.undo(m);
651 return res;
652 };
653 // Disable check tests for sentry pushes,
654 // because in this case the move isn't finished
655 let movesWithoutSentryPushes = [];
656 let movesWithSentryPushes = [];
657 moves.forEach(m => {
658 // Second condition below for special king "pass" moves
659 if (m.appear.length > 0 || m.vanish.length == 0)
660 movesWithoutSentryPushes.push(m);
661 else movesWithSentryPushes.push(m);
662 });
663 const color = this.turn;
664 const oppCol = V.GetOppCol(color);
665 const filteredMoves =
666 movesWithoutSentryPushes.filter(m => basicFilter(m, color));
667 // If at least one full move made, everything is allowed.
668 // Else: forbid checks and captures.
669 return (
670 this.movesCount >= 2
671 ? filteredMoves
672 : filteredMoves.filter(m => {
673 return (m.vanish.length <= 1 && basicFilter(m, oppCol));
674 })
675 ).concat(movesWithSentryPushes);
676 }
677
678 getAllValidMoves() {
679 if (this.subTurn == 1) return super.getAllValidMoves();
680 // Sentry push:
681 const sentrySq = [this.sentryPos.x, this.sentryPos.y];
682 return this.filterValid(this.getPotentialMovesFrom(sentrySq));
683 }
684
685 isAttacked(sq, color) {
686 return (
687 super.isAttacked(sq, color) ||
688 this.isAttackedByLancer(sq, color) ||
689 this.isAttackedBySentry(sq, color)
690 // The jailer doesn't capture.
691 );
692 }
693
694 isAttackedBySlideNJump([x, y], color, piece, steps, oneStep) {
695 for (let step of steps) {
696 let rx = x + step[0],
697 ry = y + step[1];
698 while (V.OnBoard(rx, ry) && this.board[rx][ry] == V.EMPTY && !oneStep) {
699 rx += step[0];
700 ry += step[1];
701 }
702 if (
703 V.OnBoard(rx, ry) &&
704 this.getPiece(rx, ry) == piece &&
705 this.getColor(rx, ry) == color &&
706 !this.isImmobilized([rx, ry])
707 ) {
708 return true;
709 }
710 }
711 return false;
712 }
713
714 isAttackedByPawn([x, y], color) {
715 const pawnShift = (color == "w" ? 1 : -1);
716 if (x + pawnShift >= 0 && x + pawnShift < V.size.x) {
717 for (let i of [-1, 1]) {
718 if (
719 y + i >= 0 &&
720 y + i < V.size.y &&
721 this.getPiece(x + pawnShift, y + i) == V.PAWN &&
722 this.getColor(x + pawnShift, y + i) == color &&
723 !this.isImmobilized([x + pawnShift, y + i])
724 ) {
725 return true;
726 }
727 }
728 }
729 return false;
730 }
731
732 isAttackedByLancer([x, y], color) {
733 for (let step of V.steps[V.ROOK].concat(V.steps[V.BISHOP])) {
734 // If in this direction there are only enemy pieces and empty squares,
735 // and we meet a lancer: can he reach us?
736 // NOTE: do not stop at first lancer, there might be several!
737 let coord = { x: x + step[0], y: y + step[1] };
738 let lancerPos = [];
739 while (
740 V.OnBoard(coord.x, coord.y) &&
741 (
742 this.board[coord.x][coord.y] == V.EMPTY ||
743 this.getColor(coord.x, coord.y) == color
744 )
745 ) {
746 if (
747 this.getPiece(coord.x, coord.y) == V.LANCER &&
748 !this.isImmobilized([coord.x, coord.y])
749 ) {
750 lancerPos.push({x: coord.x, y: coord.y});
751 }
752 coord.x += step[0];
753 coord.y += step[1];
754 }
755 for (let xy of lancerPos) {
756 const dir = V.LANCER_DIRS[this.board[xy.x][xy.y].charAt(1)];
757 if (dir[0] == -step[0] && dir[1] == -step[1]) return true;
758 }
759 }
760 return false;
761 }
762
763 // Helper to check sentries attacks:
764 selfAttack([x1, y1], [x2, y2]) {
765 const color = this.getColor(x1, y1);
766 const oppCol = V.GetOppCol(color);
767 const sliderAttack = (allowedSteps, lancer) => {
768 const deltaX = x2 - x1,
769 absDeltaX = Math.abs(deltaX);
770 const deltaY = y2 - y1,
771 absDeltaY = Math.abs(deltaY);
772 const step = [ deltaX / absDeltaX || 0, deltaY / absDeltaY || 0 ];
773 if (
774 // Check that the step is a priori valid:
775 (absDeltaX != absDeltaY && deltaX != 0 && deltaY != 0) ||
776 allowedSteps.every(st => st[0] != step[0] || st[1] != step[1])
777 ) {
778 return false;
779 }
780 let sq = [ x1 + step[0], y1 + step[1] ];
781 while (sq[0] != x2 || sq[1] != y2) {
782 if (
783 // NOTE: no need to check OnBoard in this special case
784 (!lancer && this.board[sq[0]][sq[1]] != V.EMPTY) ||
785 (!!lancer && this.getColor(sq[0], sq[1]) == oppCol)
786 ) {
787 return false;
788 }
789 sq[0] += step[0];
790 sq[1] += step[1];
791 }
792 return true;
793 };
794 switch (this.getPiece(x1, y1)) {
795 case V.PAWN: {
796 // Pushed pawns move as enemy pawns
797 const shift = (color == 'w' ? 1 : -1);
798 return (x1 + shift == x2 && Math.abs(y1 - y2) == 1);
799 }
800 case V.KNIGHT: {
801 const deltaX = Math.abs(x1 - x2);
802 const deltaY = Math.abs(y1 - y2);
803 return (
804 deltaX + deltaY == 3 &&
805 [1, 2].includes(deltaX) &&
806 [1, 2].includes(deltaY)
807 );
808 }
809 case V.ROOK:
810 return sliderAttack(V.steps[V.ROOK]);
811 case V.BISHOP:
812 return sliderAttack(V.steps[V.BISHOP]);
813 case V.QUEEN:
814 return sliderAttack(V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
815 case V.LANCER: {
816 // Special case: as long as no enemy units stands in-between,
817 // it attacks (if it points toward the king).
818 const allowedStep = V.LANCER_DIRS[this.board[x1][y1].charAt(1)];
819 return sliderAttack([allowedStep], "lancer");
820 }
821 // No sentries or jailer tests: they cannot self-capture
822 }
823 return false;
824 }
825
826 isAttackedBySentry([x, y], color) {
827 // Attacked by sentry means it can self-take our king.
828 // Just check diagonals of enemy sentry(ies), and if it reaches
829 // one of our pieces: can I self-take?
830 const myColor = V.GetOppCol(color);
831 let candidates = [];
832 for (let i=0; i<V.size.x; i++) {
833 for (let j=0; j<V.size.y; j++) {
834 if (
835 this.getPiece(i,j) == V.SENTRY &&
836 this.getColor(i,j) == color &&
837 !this.isImmobilized([i, j])
838 ) {
839 for (let step of V.steps[V.BISHOP]) {
840 let sq = [ i + step[0], j + step[1] ];
841 while (
842 V.OnBoard(sq[0], sq[1]) &&
843 this.board[sq[0]][sq[1]] == V.EMPTY
844 ) {
845 sq[0] += step[0];
846 sq[1] += step[1];
847 }
848 if (
849 V.OnBoard(sq[0], sq[1]) &&
850 this.getColor(sq[0], sq[1]) == myColor
851 ) {
852 candidates.push([ sq[0], sq[1] ]);
853 }
854 }
855 }
856 }
857 }
858 for (let c of candidates)
859 if (this.selfAttack(c, [x, y])) return true;
860 return false;
861 }
862
863 // Jailer doesn't capture or give check
864
865 prePlay(move) {
866 if (move.appear.length == 0 && move.vanish.length == 1)
867 // The sentry is about to push a piece: subTurn goes from 1 to 2
868 this.sentryPos = { x: move.end.x, y: move.end.y };
869 if (this.subTurn == 2 && move.vanish[0].p != V.PAWN) {
870 // A piece is pushed: forbid array of squares between start and end
871 // of move, included (except if it's a pawn)
872 let squares = [];
873 if ([V.KNIGHT,V.KING].includes(move.vanish[0].p))
874 // short-range pieces: just forbid initial square
875 squares.push({ x: move.start.x, y: move.start.y });
876 else {
877 const deltaX = move.end.x - move.start.x;
878 const deltaY = move.end.y - move.start.y;
879 const step = [
880 deltaX / Math.abs(deltaX) || 0,
881 deltaY / Math.abs(deltaY) || 0
882 ];
883 for (
884 let sq = {x: move.start.x, y: move.start.y};
885 sq.x != move.end.x || sq.y != move.end.y;
886 sq.x += step[0], sq.y += step[1]
887 ) {
888 squares.push({ x: sq.x, y: sq.y });
889 }
890 }
891 // Add end square as well, to know if I was pushed (useful for lancers)
892 squares.push({ x: move.end.x, y: move.end.y });
893 this.sentryPush.push(squares);
894 } else this.sentryPush.push(null);
895 }
896
897 play(move) {
898 this.prePlay(move);
899 move.flags = JSON.stringify(this.aggregateFlags());
900 this.epSquares.push(this.getEpSquare(move));
901 V.PlayOnBoard(this.board, move);
902 // Is it a sentry push? (useful for undo)
903 move.sentryPush = (this.subTurn == 2);
904 if (this.subTurn == 1) this.movesCount++;
905 if (move.appear.length == 0 && move.vanish.length == 1) this.subTurn = 2;
906 else {
907 // Turn changes only if not a sentry "pre-push"
908 this.turn = V.GetOppCol(this.turn);
909 this.subTurn = 1;
910 }
911 this.postPlay(move);
912 }
913
914 postPlay(move) {
915 if (move.vanish.length == 0 || this.subTurn == 2)
916 // Special pass move of the king, or sentry pre-push: nothing to update
917 return;
918 const c = move.vanish[0].c;
919 const piece = move.vanish[0].p;
920 const firstRank = c == "w" ? V.size.x - 1 : 0;
921
922 if (piece == V.KING) {
923 this.kingPos[c][0] = move.appear[0].x;
924 this.kingPos[c][1] = move.appear[0].y;
925 this.castleFlags[c] = [V.size.y, V.size.y];
926 return;
927 }
928 // Update castling flags if rooks are moved
929 const oppCol = V.GetOppCol(c);
930 const oppFirstRank = V.size.x - 1 - firstRank;
931 if (
932 move.start.x == firstRank && //our rook moves?
933 this.castleFlags[c].includes(move.start.y)
934 ) {
935 const flagIdx = (move.start.y == this.castleFlags[c][0] ? 0 : 1);
936 this.castleFlags[c][flagIdx] = V.size.y;
937 } else if (
938 move.end.x == oppFirstRank && //we took opponent rook?
939 this.castleFlags[oppCol].includes(move.end.y)
940 ) {
941 const flagIdx = (move.end.y == this.castleFlags[oppCol][0] ? 0 : 1);
942 this.castleFlags[oppCol][flagIdx] = V.size.y;
943 }
944 }
945
946 undo(move) {
947 this.epSquares.pop();
948 this.disaggregateFlags(JSON.parse(move.flags));
949 V.UndoOnBoard(this.board, move);
950 // Decrement movesCount except if the move is a sentry push
951 if (!move.sentryPush) this.movesCount--;
952 if (this.subTurn == 2) this.subTurn = 1;
953 else {
954 this.turn = V.GetOppCol(this.turn);
955 if (move.sentryPush) this.subTurn = 2;
956 }
957 this.postUndo(move);
958 }
959
960 postUndo(move) {
961 super.postUndo(move);
962 this.sentryPush.pop();
963 }
964
965 static get VALUES() {
966 return Object.assign(
967 { l: 4.8, s: 2.8, j: 3.8 }, //Jeff K. estimations
968 ChessRules.VALUES
969 );
970 }
971
972 getComputerMove() {
973 const maxeval = V.INFINITY;
974 const color = this.turn;
975 let moves1 = this.getAllValidMoves();
976
977 if (moves1.length == 0)
978 // TODO: this situation should not happen
979 return null;
980
981 const setEval = (move, next) => {
982 const score = this.getCurrentScore();
983 const curEval = move.eval;
984 if (score != "*") {
985 move.eval =
986 score == "1/2"
987 ? 0
988 : (score == "1-0" ? 1 : -1) * maxeval;
989 } else move.eval = this.evalPosition();
990 if (
991 // "next" is defined after sentry pushes
992 !!next && (
993 !curEval ||
994 color == 'w' && move.eval > curEval ||
995 color == 'b' && move.eval < curEval
996 )
997 ) {
998 move.second = next;
999 }
1000 };
1001
1002 // Just search_depth == 1 (because of sentries. TODO: can do better...)
1003 moves1.forEach(m1 => {
1004 this.play(m1);
1005 if (this.subTurn == 1) setEval(m1);
1006 else {
1007 // Need to play every pushes and count:
1008 const moves2 = this.getAllValidMoves();
1009 moves2.forEach(m2 => {
1010 this.play(m2);
1011 setEval(m1, m2);
1012 this.undo(m2);
1013 });
1014 }
1015 this.undo(m1);
1016 });
1017
1018 moves1.sort((a, b) => {
1019 return (color == "w" ? 1 : -1) * (b.eval - a.eval);
1020 });
1021 let candidates = [0];
1022 for (let j = 1; j < moves1.length && moves1[j].eval == moves1[0].eval; j++)
1023 candidates.push(j);
1024 const choice = moves1[candidates[randInt(candidates.length)]];
1025 return (!choice.second ? choice : [choice, choice.second]);
1026 }
1027
1028 // For moves notation:
1029 static get LANCER_DIRNAMES() {
1030 return {
1031 'c': "N",
1032 'd': "NE",
1033 'e': "E",
1034 'f': "SE",
1035 'g': "S",
1036 'h': "SW",
1037 'm': "W",
1038 'o': "NW"
1039 };
1040 }
1041
1042 getNotation(move) {
1043 // Special case "king takes jailer" is a pass move
1044 if (move.appear.length == 0 && move.vanish.length == 0) return "pass";
1045 let notation = undefined;
1046 if (this.subTurn == 2) {
1047 // Do not consider appear[1] (sentry) for sentry pushes
1048 const simpleMove = {
1049 appear: [move.appear[0]],
1050 vanish: move.vanish,
1051 start: move.start,
1052 end: move.end
1053 };
1054 notation = super.getNotation(simpleMove);
1055 } else notation = super.getNotation(move);
1056 if (Object.keys(V.LANCER_DIRNAMES).includes(move.vanish[0].p))
1057 // Lancer: add direction info
1058 notation += "=" + V.LANCER_DIRNAMES[move.appear[0].p];
1059 else if (
1060 move.vanish[0].p == V.PAWN &&
1061 Object.keys(V.LANCER_DIRNAMES).includes(move.appear[0].p)
1062 ) {
1063 // Fix promotions in lancer:
1064 notation = notation.slice(0, -1) +
1065 "L:" + V.LANCER_DIRNAMES[move.appear[0].p];
1066 }
1067 return notation;
1068 }
1069 };