1 import { ChessRules
, Move
, PiPo
} from "@/base_rules";
2 import { randInt
} from "@/utils/alea";
4 export class DynamoRules
extends ChessRules
{
5 // TODO: later, allow to push out pawns on a and h files
6 static get HasEnpassant() {
10 canIplay(side
, [x
, y
]) {
11 // Sometimes opponent's pieces can be moved directly
15 setOtherVariables(fen
) {
16 super.setOtherVariables(fen
);
18 // Local stack of "action moves"
20 const amove
= V
.ParseFen(fen
).amove
;
22 const amoveParts
= amove
.split("/");
24 // No need for start & end
29 if (amoveParts
[i
] != "-") {
30 amoveParts
[i
].split(".").forEach(av
=> {
32 const xy
= V
.SquareToCoords(av
.substr(2));
33 move[i
== 0 ? "appear" : "vanish"].push(
44 this.amoves
.push(move);
47 // Stack "first moves" (on subTurn 1) to merge and check opposite moves
51 static ParseFen(fen
) {
53 ChessRules
.ParseFen(fen
),
54 { amove: fen
.split(" ")[4] }
58 static IsGoodFen(fen
) {
59 if (!ChessRules
.IsGoodFen(fen
)) return false;
60 const fenParts
= fen
.split(" ");
61 if (fenParts
.length
!= 5) return false;
62 if (fenParts
[4] != "-") {
63 // TODO: a single regexp instead.
64 // Format is [bpa2[.wpd3]] || '-'/[bbc3[.wrd5]] || '-'
65 const amoveParts
= fenParts
[4].split("/");
66 if (amoveParts
.length
!= 2) return false;
67 for (let part
of amoveParts
) {
69 for (let psq
of part
.split("."))
70 if (!psq
.match(/^[a-r]{3}[1-8]$/)) return false;
78 return super.getFen() + " " + this.getAmoveFen();
82 return super.getFenForRepeat() + "_" + this.getAmoveFen();
86 const L
= this.amoves
.length
;
87 if (L
== 0) return "-";
89 ["appear","vanish"].map(
91 if (mpart
.length
== 0) return "-";
93 this.amoves
[L
-1][mpart
].map(
95 const square
= V
.CoordsToSquare({ x: av
.x
, y: av
.y
});
96 return av
.c
+ av
.p
+ square
;
106 // Captures don't occur (only pulls & pushes)
110 // Step is right, just add (push/pull) moves in this direction
111 // Direction is assumed normalized.
112 getMovesInDirection([x
, y
], [dx
, dy
], nbSteps
) {
113 nbSteps
= nbSteps
|| 8; //max 8 steps anyway
114 let [i
, j
] = [x
+ dx
, y
+ dy
];
116 const color
= this.getColor(x
, y
);
117 const piece
= this.getPiece(x
, y
);
118 const lastRank
= (color
== 'w' ? 0 : 7);
120 while (V
.OnBoard(i
, j
) && this.board
[i
][j
] == V
.EMPTY
) {
121 if (i
== lastRank
&& piece
== V
.PAWN
) {
122 // Promotion by push or pull
123 V
.PawnSpecs
.promotions
.forEach(p
=> {
124 let move = super.getBasicMove([x
, y
], [i
, j
], { c: color
, p: p
});
128 else moves
.push(super.getBasicMove([x
, y
], [i
, j
]));
129 if (++counter
> nbSteps
) break;
133 if (!V
.OnBoard(i
, j
) && piece
!= V
.KING
) {
134 // Add special "exit" move, by "taking king"
137 start: { x: x
, y: y
},
138 end: { x: this.kingPos
[color
][0], y: this.kingPos
[color
][1] },
140 vanish: [{ x: x
, y: y
, c: color
, p: piece
}]
147 // Normalize direction to know the step
148 getNormalizedDirection([dx
, dy
]) {
149 const absDir
= [Math
.abs(dx
), Math
.abs(dy
)];
151 if (absDir
[0] != 0 && absDir
[1] != 0 && absDir
[0] != absDir
[1])
153 divisor
= Math
.min(absDir
[0], absDir
[1]);
155 // Standard slider (or maybe a pawn or king: same)
156 divisor
= Math
.max(absDir
[0], absDir
[1]);
157 return [dx
/ divisor
, dy
/ divisor
];
160 // There was something on x2,y2, maybe our color, pushed/pulled.
161 // Also, the pushed/pulled piece must exit the board.
162 isAprioriValidExit([x1
, y1
], [x2
, y2
], color2
) {
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
) {
175 return !V
.OnBoard(i
, j
);
177 switch (this.getPiece(x1
, y1
)) {
180 x1
+ pawnShift
== x2
&&
182 (color1
== color2
&& x2
== lastRank
&& y1
== y2
) ||
183 (color1
!= color2
&& deltaY
== 1 && !V
.OnBoard(x2
, 2 * y2
- y1
))
187 if (x1
!= x2
&& y1
!= y2
) return false;
188 return checkSlider();
191 deltaX
+ deltaY
== 3 &&
192 (deltaX
== 1 || deltaY
== 1) &&
193 !V
.OnBoard(2 * x2
- x1
, 2 * y2
- y1
)
196 if (deltaX
!= deltaY
) return false;
197 return checkSlider();
199 if (deltaX
!= 0 && deltaY
!= 0 && deltaX
!= deltaY
) return false;
200 return checkSlider();
205 !V
.OnBoard(2 * x2
- x1
, 2 * y2
- y1
)
211 // NOTE: for pushes, play the pushed piece first.
212 // for pulls: play the piece doing the action first
213 // NOTE: to push a piece out of the board, make it slide until its king
214 getPotentialMovesFrom([x
, y
]) {
215 const color
= this.turn
;
216 if (this.subTurn
== 1) {
217 const getMoveHash
= (m
) => {
218 return V
.CoordsToSquare(m
.start
) + V
.CoordsToSquare(m
.end
);
220 const addMoves
= (dir
, nbSteps
) => {
222 this.getMovesInDirection([x
, y
], [-dir
[0], -dir
[1]], nbSteps
)
223 .filter(m
=> !movesHash
[getMoveHash(m
)]);
224 newMoves
.forEach(m
=> { movesHash
[getMoveHash(m
)] = true; });
225 Array
.prototype.push
.apply(moves
, newMoves
);
227 // Free to play any move (if piece of my color):
229 this.getColor(x
, y
) == color
230 ? super.getPotentialMovesFrom([x
, y
])
232 const pawnShift
= (color
== 'w' ? -1 : 1);
233 const pawnStartRank
= (color
== 'w' ? 6 : 1);
234 // Structure to avoid adding moves twice (can be action & move)
236 moves
.forEach(m
=> { movesHash
[getMoveHash(m
)] = true; });
237 // [x, y] is pushed by 'color'
238 for (let step
of V
.steps
[V
.KNIGHT
]) {
239 const [i
, j
] = [x
+ step
[0], y
+ step
[1]];
242 this.board
[i
][j
] != V
.EMPTY
&&
243 this.getColor(i
, j
) == color
&&
244 this.getPiece(i
, j
) == V
.KNIGHT
249 for (let step
of V
.steps
[V
.ROOK
].concat(V
.steps
[V
.BISHOP
])) {
250 let [i
, j
] = [x
+ step
[0], y
+ step
[1]];
251 while (V
.OnBoard(i
, j
) && this.board
[i
][j
] == V
.EMPTY
) {
257 this.board
[i
][j
] != V
.EMPTY
&&
258 this.getColor(i
, j
) == color
260 const deltaX
= Math
.abs(i
- x
);
261 const deltaY
= Math
.abs(j
- y
);
262 // Can a priori go both ways, except with pawns
263 switch (this.getPiece(i
, j
)) {
266 (x
- i
) / deltaX
== pawnShift
&&
270 const pColor
= this.getColor(x
, y
);
271 if (pColor
== color
&& deltaY
== 0) {
273 const maxSteps
= (i
== pawnStartRank
&& deltaX
== 1 ? 2 : 1);
274 addMoves(step
, maxSteps
);
276 else if (pColor
!= color
&& deltaY
== 1 && deltaX
== 1)
282 if (deltaX
== 0 || deltaY
== 0) addMoves(step
);
285 if (deltaX
== deltaY
) addMoves(step
);
288 if (deltaX
== 0 || deltaY
== 0 || deltaX
== deltaY
)
292 if (deltaX
<= 1 && deltaY
<= 1) addMoves(step
, 1);
299 // If subTurn == 2 then we should have a first move,
300 // which restrict what we can play now: only in the first move direction
301 // NOTE: no need for knight or pawn checks, because the move will be
302 // naturally limited in those cases.
303 const L
= this.firstMove
.length
;
304 const fm
= this.firstMove
[L
-1];
305 if (fm
.appear
.length
== 2 && fm
.vanish
.length
== 2)
306 // Castle: no real move playable then.
308 if (fm
.appear
.length
== 0) {
309 // Piece at subTurn 1 just exited the board.
310 // Can I be a piece which caused the exit?
312 this.isAprioriValidExit(
314 [fm
.start
.x
, fm
.start
.y
],
319 const dir
= this.getNormalizedDirection(
320 [fm
.start
.x
- x
, fm
.start
.y
- y
]);
321 return this.getMovesInDirection([x
, y
], dir
);
325 const dirM
= this.getNormalizedDirection(
326 [fm
.end
.x
- fm
.start
.x
, fm
.end
.y
- fm
.start
.y
]);
327 const dir
= this.getNormalizedDirection(
328 [fm
.start
.x
- x
, fm
.start
.y
- y
]);
329 // Normalized directions should match
330 if (dir
[0] == dirM
[0] && dir
[1] == dirM
[1]) {
331 // And nothing should stand between [x, y] and the square fm.start
332 let [i
, j
] = [x
+ dir
[0], y
+ dir
[1]];
334 (i
!= fm
.start
.x
|| j
!= fm
.start
.y
) &&
335 this.board
[i
][j
] == V
.EMPTY
340 if (i
== fm
.start
.x
&& j
== fm
.start
.y
)
341 return this.getMovesInDirection([x
, y
], dir
);
347 // Does m2 un-do m1 ? (to disallow undoing actions)
348 oppositeMoves(m1
, m2
) {
349 const isEqual
= (av1
, av2
) => {
350 // Precondition: av1 and av2 length = 2
351 for (let av
of av1
) {
352 const avInAv2
= av2
.find(elt
=> {
360 if (!avInAv2
) return false;
365 m1
.appear
.length
== 2 &&
366 m2
.appear
.length
== 2 &&
367 m1
.vanish
.length
== 2 &&
368 m2
.vanish
.length
== 2 &&
369 isEqual(m1
.appear
, m2
.vanish
) &&
370 isEqual(m1
.vanish
, m2
.appear
)
374 getAmove(move1
, move2
) {
375 // Just merge (one is action one is move, one may be empty)
377 appear: move1
.appear
.concat(move2
.appear
),
378 vanish: move1
.vanish
.concat(move2
.vanish
)
383 const color
= this.turn
;
384 if (this.subTurn
== 1) {
385 return moves
.filter(m
=> {
386 // A move is valid either if it doesn't result in a check,
387 // or if a second move is possible to counter the check
388 // (not undoing a potential move + action of the opponent)
390 let res
= this.underCheck(color
);
392 const moves2
= this.getAllPotentialMoves();
393 for (let m2
of moves2
) {
395 const res2
= this.underCheck(color
);
407 const Lf
= this.firstMove
.length
;
408 const La
= this.amoves
.length
;
409 if (La
== 0) return super.filterValid(moves
);
413 // Move shouldn't undo another:
414 const amove
= this.getAmove(this.firstMove
[Lf
-1], m
);
415 return !this.oppositeMoves(this.amoves
[La
-1], amove
);
421 isAttackedBySlideNJump([x
, y
], color
, piece
, steps
, oneStep
) {
422 for (let step
of steps
) {
423 let rx
= x
+ step
[0],
425 while (V
.OnBoard(rx
, ry
) && this.board
[rx
][ry
] == V
.EMPTY
&& !oneStep
) {
431 this.getPiece(rx
, ry
) == piece
&&
432 this.getColor(rx
, ry
) == color
434 // Continue some steps in the same direction (pull)
439 this.board
[rx
][ry
] == V
.EMPTY
&&
445 if (!V
.OnBoard(rx
, ry
)) return true;
446 // Step in the other direction (push)
451 this.board
[rx
][ry
] == V
.EMPTY
&&
457 if (!V
.OnBoard(rx
, ry
)) return true;
463 isAttackedByPawn([x
, y
], color
) {
464 const lastRank
= (color
== 'w' ? 0 : 7);
466 // The king can be pushed out by a pawn only on last rank
468 const pawnShift
= (color
== "w" ? 1 : -1);
469 for (let i
of [-1, 1]) {
473 this.getPiece(x
+ pawnShift
, y
+ i
) == V
.PAWN
&&
474 this.getColor(x
+ pawnShift
, y
+ i
) == color
483 if (this.subTurn
== 2)
486 return super.getCurrentScore();
490 // If subTurn == 2 && square is empty && !underCheck,
491 // then return an empty move, allowing to "pass" subTurn2
494 this.board
[square
[0]][square
[1]] == V
.EMPTY
&&
495 !this.underCheck(this.turn
)
498 start: { x: -1, y: -1 },
499 end: { x: -1, y: -1 },
508 move.flags
= JSON
.stringify(this.aggregateFlags());
509 V
.PlayOnBoard(this.board
, move);
510 if (this.subTurn
== 2) {
511 const L
= this.firstMove
.length
;
512 this.amoves
.push(this.getAmove(this.firstMove
[L
-1], move));
513 this.turn
= V
.GetOppCol(this.turn
);
516 else this.firstMove
.push(move);
517 this.subTurn
= 3 - this.subTurn
;
522 if (move.start
.x
< 0) return;
523 for (let a
of move.appear
)
524 if (a
.p
== V
.KING
) this.kingPos
[a
.c
] = [a
.x
, a
.y
];
525 this.updateCastleFlags(move);
528 updateCastleFlags(move) {
529 const firstRank
= { 'w': V
.size
.x
- 1, 'b': 0 };
530 for (let v
of move.vanish
) {
531 if (v
.p
== V
.KING
) this.castleFlags
[v
.c
] = [V
.size
.y
, V
.size
.y
];
532 else if (v
.x
== firstRank
[v
.c
] && this.castleFlags
[v
.c
].includes(v
.y
)) {
533 const flagIdx
= (v
.y
== this.castleFlags
[v
.c
][0] ? 0 : 1);
534 this.castleFlags
[v
.c
][flagIdx
] = V
.size
.y
;
540 this.disaggregateFlags(JSON
.parse(move.flags
));
541 V
.UndoOnBoard(this.board
, move);
542 if (this.subTurn
== 1) {
543 this.turn
= V
.GetOppCol(this.turn
);
546 else this.firstMove
.pop();
547 this.subTurn
= 3 - this.subTurn
;
552 // (Potentially) Reset king position
553 for (let v
of move.vanish
)
554 if (v
.p
== V
.KING
) this.kingPos
[v
.c
] = [v
.x
, v
.y
];
558 let moves
= this.getAllValidMoves();
559 if (moves
.length
== 0) return null;
560 // "Search" at depth 1 for now
561 const maxeval
= V
.INFINITY
;
562 const color
= this.turn
;
564 start: { x: -1, y: -1 },
565 end: { x: -1, y: -1 },
571 m
.eval
= (color
== "w" ? -1 : 1) * maxeval
;
572 const moves2
= this.getAllValidMoves().concat([emptyMove
]);
574 moves2
.forEach(m2
=> {
576 const score
= this.getCurrentScore();
578 if (score
!= "1/2") {
579 if (score
!= "*") mvEval
= (score
== "1-0" ? 1 : -1) * maxeval
;
580 else mvEval
= this.evalPosition();
583 (color
== 'w' && mvEval
> m
.eval
) ||
584 (color
== 'b' && mvEval
< m
.eval
)
593 moves
.sort((a
, b
) => {
594 return (color
== "w" ? 1 : -1) * (b
.eval
- a
.eval
);
596 let candidates
= [0];
597 for (let i
= 1; i
< moves
.length
&& moves
[i
].eval
== moves
[0].eval
; i
++)
599 const mIdx
= candidates
[randInt(candidates
.length
)];
600 const move2
= moves
[mIdx
].next
;
601 delete moves
[mIdx
]["next"];
602 return [moves
[mIdx
], move2
];
606 if (move.start
.x
< 0)
607 // A second move is always required, but may be empty
609 const initialSquare
= V
.CoordsToSquare(move.start
);
610 const finalSquare
= V
.CoordsToSquare(move.end
);
611 if (move.appear
.length
== 0)
612 // Pushed or pulled out of the board
613 return initialSquare
+ "R";
614 return move.appear
[0].p
.toUpperCase() + initialSquare
+ finalSquare
;