Commit | Line | Data |
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92342261 BA |
1 | // (Orthodox) Chess rules are defined in ChessRules class. |
2 | // Variants generally inherit from it, and modify some parts. | |
3 | ||
1d184b4c BA |
4 | class PiPo //Piece+Position |
5 | { | |
6 | // o: {piece[p], color[c], posX[x], posY[y]} | |
7 | constructor(o) | |
8 | { | |
9 | this.p = o.p; | |
10 | this.c = o.c; | |
11 | this.x = o.x; | |
12 | this.y = o.y; | |
13 | } | |
14 | } | |
15 | ||
098e8468 | 16 | // TODO: for animation, moves should contains "moving" and "fading" maybe... |
1d184b4c BA |
17 | class Move |
18 | { | |
19 | // o: {appear, vanish, [start,] [end,]} | |
20 | // appear,vanish = arrays of PiPo | |
21 | // start,end = coordinates to apply to trigger move visually (think castle) | |
22 | constructor(o) | |
23 | { | |
24 | this.appear = o.appear; | |
25 | this.vanish = o.vanish; | |
26 | this.start = !!o.start ? o.start : {x:o.vanish[0].x, y:o.vanish[0].y}; | |
27 | this.end = !!o.end ? o.end : {x:o.appear[0].x, y:o.appear[0].y}; | |
28 | } | |
29 | } | |
30 | ||
31 | // NOTE: x coords = top to bottom; y = left to right (from white player perspective) | |
32 | class ChessRules | |
33 | { | |
34 | // Path to pieces | |
35 | static getPpath(b) | |
36 | { | |
37 | return b; //usual pieces in pieces/ folder | |
38 | } | |
39 | // Turn "wb" into "B" (for FEN) | |
40 | static board2fen(b) | |
41 | { | |
42 | return b[0]=='w' ? b[1].toUpperCase() : b[1]; | |
43 | } | |
44 | // Turn "p" into "bp" (for board) | |
45 | static fen2board(f) | |
46 | { | |
47 | return f.charCodeAt()<=90 ? "w"+f.toLowerCase() : "b"+f; | |
48 | } | |
49 | ||
50 | ///////////////// | |
51 | // INITIALIZATION | |
52 | ||
d3334c3a | 53 | // fen == "position flags" |
dfb4afc1 | 54 | constructor(fen, moves) |
1d184b4c | 55 | { |
dfb4afc1 | 56 | this.moves = moves; |
1d184b4c | 57 | // Use fen string to initialize variables, flags and board |
0b7d99ec | 58 | this.board = V.GetBoard(fen); |
2526c041 | 59 | this.setFlags(fen); |
ffbae57a | 60 | this.initVariables(fen); |
1d184b4c BA |
61 | } |
62 | ||
63 | initVariables(fen) | |
64 | { | |
65 | this.INIT_COL_KING = {'w':-1, 'b':-1}; | |
66 | this.INIT_COL_ROOK = {'w':[-1,-1], 'b':[-1,-1]}; | |
92342261 | 67 | this.kingPos = {'w':[-1,-1], 'b':[-1,-1]}; //squares of white and black king |
1d184b4c BA |
68 | const fenParts = fen.split(" "); |
69 | const position = fenParts[0].split("/"); | |
70 | for (let i=0; i<position.length; i++) | |
71 | { | |
6037f1d8 BA |
72 | let k = 0; //column index on board |
73 | for (let j=0; j<position[i].length; j++) | |
1d184b4c BA |
74 | { |
75 | switch (position[i].charAt(j)) | |
76 | { | |
77 | case 'k': | |
6037f1d8 BA |
78 | this.kingPos['b'] = [i,k]; |
79 | this.INIT_COL_KING['b'] = k; | |
1d184b4c BA |
80 | break; |
81 | case 'K': | |
6037f1d8 BA |
82 | this.kingPos['w'] = [i,k]; |
83 | this.INIT_COL_KING['w'] = k; | |
1d184b4c BA |
84 | break; |
85 | case 'r': | |
86 | if (this.INIT_COL_ROOK['b'][0] < 0) | |
6037f1d8 | 87 | this.INIT_COL_ROOK['b'][0] = k; |
1d184b4c | 88 | else |
6037f1d8 | 89 | this.INIT_COL_ROOK['b'][1] = k; |
1d184b4c BA |
90 | break; |
91 | case 'R': | |
92 | if (this.INIT_COL_ROOK['w'][0] < 0) | |
6037f1d8 | 93 | this.INIT_COL_ROOK['w'][0] = k; |
1d184b4c | 94 | else |
6037f1d8 | 95 | this.INIT_COL_ROOK['w'][1] = k; |
1d184b4c BA |
96 | break; |
97 | default: | |
98 | let num = parseInt(position[i].charAt(j)); | |
99 | if (!isNaN(num)) | |
6037f1d8 | 100 | k += (num-1); |
1d184b4c | 101 | } |
6037f1d8 | 102 | k++; |
1d184b4c BA |
103 | } |
104 | } | |
0b7d99ec | 105 | const epSq = (this.moves.length > 0 ? this.getEpSquare(this.lastMove) : undefined); |
1d184b4c | 106 | this.epSquares = [ epSq ]; |
1d184b4c BA |
107 | } |
108 | ||
109 | // Turn diagram fen into double array ["wb","wp","bk",...] | |
110 | static GetBoard(fen) | |
111 | { | |
112 | let rows = fen.split(" ")[0].split("/"); | |
0b7d99ec | 113 | let board = doubleArray(V.size.x, V.size.y, ""); |
1d184b4c BA |
114 | for (let i=0; i<rows.length; i++) |
115 | { | |
116 | let j = 0; | |
117 | for (let indexInRow = 0; indexInRow < rows[i].length; indexInRow++) | |
118 | { | |
119 | let character = rows[i][indexInRow]; | |
120 | let num = parseInt(character); | |
121 | if (!isNaN(num)) | |
122 | j += num; //just shift j | |
123 | else //something at position i,j | |
0b7d99ec | 124 | board[i][j++] = V.fen2board(character); |
1d184b4c BA |
125 | } |
126 | } | |
127 | return board; | |
128 | } | |
129 | ||
dda21a71 | 130 | // Extract (relevant) flags from fen |
2526c041 | 131 | setFlags(fen) |
1d184b4c BA |
132 | { |
133 | // white a-castle, h-castle, black a-castle, h-castle | |
2526c041 BA |
134 | this.castleFlags = {'w': new Array(2), 'b': new Array(2)}; |
135 | let flags = fen.split(" ")[1]; //flags right after position | |
1d184b4c | 136 | for (let i=0; i<4; i++) |
2526c041 | 137 | this.castleFlags[i < 2 ? 'w' : 'b'][i%2] = (flags.charAt(i) == '1'); |
1d184b4c BA |
138 | } |
139 | ||
140 | /////////////////// | |
141 | // GETTERS, SETTERS | |
142 | ||
0b7d99ec BA |
143 | static get size() { return {x:8, y:8}; } |
144 | ||
1d184b4c BA |
145 | // Two next functions return 'undefined' if called on empty square |
146 | getColor(i,j) { return this.board[i][j].charAt(0); } | |
147 | getPiece(i,j) { return this.board[i][j].charAt(1); } | |
148 | ||
149 | // Color | |
0b7d99ec | 150 | getOppCol(color) { return (color=="w" ? "b" : "w"); } |
1d184b4c BA |
151 | |
152 | get lastMove() { | |
153 | const L = this.moves.length; | |
0b7d99ec | 154 | return (L>0 ? this.moves[L-1] : null); |
1d184b4c | 155 | } |
0b7d99ec | 156 | |
1d184b4c | 157 | get turn() { |
0b7d99ec | 158 | return (this.moves.length%2==0 ? 'w' : 'b'); |
1d184b4c BA |
159 | } |
160 | ||
161 | // Pieces codes | |
162 | static get PAWN() { return 'p'; } | |
163 | static get ROOK() { return 'r'; } | |
164 | static get KNIGHT() { return 'n'; } | |
165 | static get BISHOP() { return 'b'; } | |
166 | static get QUEEN() { return 'q'; } | |
167 | static get KING() { return 'k'; } | |
168 | ||
169 | // Empty square | |
170 | static get EMPTY() { return ''; } | |
171 | ||
172 | // Some pieces movements | |
173 | static get steps() { | |
174 | return { | |
175 | 'r': [ [-1,0],[1,0],[0,-1],[0,1] ], | |
176 | 'n': [ [-1,-2],[-1,2],[1,-2],[1,2],[-2,-1],[-2,1],[2,-1],[2,1] ], | |
177 | 'b': [ [-1,-1],[-1,1],[1,-1],[1,1] ], | |
1d184b4c BA |
178 | }; |
179 | } | |
180 | ||
2526c041 BA |
181 | // Aggregates flags into one object |
182 | get flags() { | |
183 | return this.castleFlags; | |
184 | } | |
185 | ||
186 | // Reverse operation | |
187 | parseFlags(flags) | |
188 | { | |
189 | this.castleFlags = flags; | |
190 | } | |
191 | ||
1d184b4c BA |
192 | // En-passant square, if any |
193 | getEpSquare(move) | |
194 | { | |
195 | const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x]; | |
0b7d99ec | 196 | if (this.getPiece(sx,sy) == V.PAWN && Math.abs(sx - ex) == 2) |
1d184b4c BA |
197 | { |
198 | return { | |
199 | x: (sx + ex)/2, | |
200 | y: sy | |
201 | }; | |
202 | } | |
203 | return undefined; //default | |
204 | } | |
205 | ||
dda21a71 | 206 | // Can thing on square1 take thing on square2 |
46302e64 | 207 | canTake([x1,y1], [x2,y2]) |
1d184b4c | 208 | { |
0b7d99ec | 209 | return this.getColor(x1,y1) !== this.getColor(x2,y2); |
1d184b4c BA |
210 | } |
211 | ||
212 | /////////////////// | |
213 | // MOVES GENERATION | |
214 | ||
215 | // All possible moves from selected square (assumption: color is OK) | |
216 | getPotentialMovesFrom([x,y]) | |
217 | { | |
1d184b4c BA |
218 | switch (this.getPiece(x,y)) |
219 | { | |
0b7d99ec | 220 | case V.PAWN: |
46302e64 | 221 | return this.getPotentialPawnMoves([x,y]); |
0b7d99ec | 222 | case V.ROOK: |
46302e64 | 223 | return this.getPotentialRookMoves([x,y]); |
0b7d99ec | 224 | case V.KNIGHT: |
46302e64 | 225 | return this.getPotentialKnightMoves([x,y]); |
0b7d99ec | 226 | case V.BISHOP: |
46302e64 | 227 | return this.getPotentialBishopMoves([x,y]); |
0b7d99ec | 228 | case V.QUEEN: |
46302e64 | 229 | return this.getPotentialQueenMoves([x,y]); |
0b7d99ec | 230 | case V.KING: |
46302e64 | 231 | return this.getPotentialKingMoves([x,y]); |
1d184b4c BA |
232 | } |
233 | } | |
234 | ||
235 | // Build a regular move from its initial and destination squares; tr: transformation | |
46302e64 | 236 | getBasicMove([sx,sy], [ex,ey], tr) |
1d184b4c | 237 | { |
2526c041 | 238 | let mv = new Move({ |
1d184b4c BA |
239 | appear: [ |
240 | new PiPo({ | |
241 | x: ex, | |
242 | y: ey, | |
46302e64 BA |
243 | c: !!tr ? tr.c : this.getColor(sx,sy), |
244 | p: !!tr ? tr.p : this.getPiece(sx,sy) | |
1d184b4c BA |
245 | }) |
246 | ], | |
247 | vanish: [ | |
248 | new PiPo({ | |
249 | x: sx, | |
250 | y: sy, | |
251 | c: this.getColor(sx,sy), | |
252 | p: this.getPiece(sx,sy) | |
253 | }) | |
254 | ] | |
255 | }); | |
256 | ||
257 | // The opponent piece disappears if we take it | |
0b7d99ec | 258 | if (this.board[ex][ey] != V.EMPTY) |
1d184b4c BA |
259 | { |
260 | mv.vanish.push( | |
261 | new PiPo({ | |
262 | x: ex, | |
263 | y: ey, | |
264 | c: this.getColor(ex,ey), | |
265 | p: this.getPiece(ex,ey) | |
266 | }) | |
267 | ); | |
268 | } | |
269 | return mv; | |
270 | } | |
271 | ||
0b7d99ec BA |
272 | // Is (x,y) on the chessboard? |
273 | static OnBoard(x,y) | |
274 | { | |
275 | return (x>=0 && x<V.size.x && y>=0 && y<V.size.y); | |
276 | } | |
277 | ||
1d184b4c | 278 | // Generic method to find possible moves of non-pawn pieces ("sliding or jumping") |
46302e64 | 279 | getSlideNJumpMoves([x,y], steps, oneStep) |
1d184b4c | 280 | { |
46302e64 | 281 | const color = this.getColor(x,y); |
2526c041 | 282 | let moves = []; |
1d184b4c BA |
283 | outerLoop: |
284 | for (let step of steps) | |
285 | { | |
46302e64 BA |
286 | let i = x + step[0]; |
287 | let j = y + step[1]; | |
0b7d99ec | 288 | while (V.OnBoard(i,j) && this.board[i][j] == V.EMPTY) |
1d184b4c | 289 | { |
46302e64 | 290 | moves.push(this.getBasicMove([x,y], [i,j])); |
1d184b4c BA |
291 | if (oneStep !== undefined) |
292 | continue outerLoop; | |
293 | i += step[0]; | |
294 | j += step[1]; | |
295 | } | |
0b7d99ec | 296 | if (V.OnBoard(i,j) && this.canTake([x,y], [i,j])) |
46302e64 | 297 | moves.push(this.getBasicMove([x,y], [i,j])); |
1d184b4c BA |
298 | } |
299 | return moves; | |
300 | } | |
301 | ||
dda21a71 | 302 | // What are the pawn moves from square x,y ? |
46302e64 | 303 | getPotentialPawnMoves([x,y]) |
1d184b4c | 304 | { |
2526c041 BA |
305 | const color = this.turn; |
306 | let moves = []; | |
0b7d99ec | 307 | const [sizeX,sizeY] = [V.size.x,V.size.y]; |
2526c041 | 308 | const shift = (color == "w" ? -1 : 1); |
cf130369 BA |
309 | const firstRank = (color == 'w' ? sizeX-1 : 0); |
310 | const startRank = (color == "w" ? sizeX-2 : 1); | |
311 | const lastRank = (color == "w" ? 0 : sizeX-1); | |
1d184b4c BA |
312 | |
313 | if (x+shift >= 0 && x+shift < sizeX && x+shift != lastRank) | |
314 | { | |
315 | // Normal moves | |
316 | if (this.board[x+shift][y] == V.EMPTY) | |
317 | { | |
46302e64 | 318 | moves.push(this.getBasicMove([x,y], [x+shift,y])); |
1221ac47 | 319 | // Next condition because variants with pawns on 1st rank allow them to jump |
2526c041 | 320 | if ([startRank,firstRank].includes(x) && this.board[x+2*shift][y] == V.EMPTY) |
1d184b4c BA |
321 | { |
322 | // Two squares jump | |
46302e64 | 323 | moves.push(this.getBasicMove([x,y], [x+2*shift,y])); |
1d184b4c BA |
324 | } |
325 | } | |
326 | // Captures | |
0b7d99ec BA |
327 | if (y>0 && this.board[x+shift][y-1] != V.EMPTY |
328 | && this.canTake([x,y], [x+shift,y-1])) | |
1221ac47 | 329 | { |
46302e64 | 330 | moves.push(this.getBasicMove([x,y], [x+shift,y-1])); |
1221ac47 | 331 | } |
0b7d99ec BA |
332 | if (y<sizeY-1 && this.board[x+shift][y+1] != V.EMPTY |
333 | && this.canTake([x,y], [x+shift,y+1])) | |
1221ac47 | 334 | { |
46302e64 | 335 | moves.push(this.getBasicMove([x,y], [x+shift,y+1])); |
1221ac47 | 336 | } |
1d184b4c BA |
337 | } |
338 | ||
339 | if (x+shift == lastRank) | |
340 | { | |
341 | // Promotion | |
68f5ccc8 | 342 | const pawnColor = this.getColor(x,y); //can be different for checkered |
1d184b4c BA |
343 | let promotionPieces = [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN]; |
344 | promotionPieces.forEach(p => { | |
345 | // Normal move | |
346 | if (this.board[x+shift][y] == V.EMPTY) | |
68f5ccc8 | 347 | moves.push(this.getBasicMove([x,y], [x+shift,y], {c:pawnColor,p:p})); |
1d184b4c | 348 | // Captures |
0b7d99ec BA |
349 | if (y>0 && this.board[x+shift][y-1] != V.EMPTY |
350 | && this.canTake([x,y], [x+shift,y-1])) | |
1221ac47 | 351 | { |
68f5ccc8 | 352 | moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:pawnColor,p:p})); |
1221ac47 | 353 | } |
0b7d99ec BA |
354 | if (y<sizeY-1 && this.board[x+shift][y+1] != V.EMPTY |
355 | && this.canTake([x,y], [x+shift,y+1])) | |
1221ac47 | 356 | { |
68f5ccc8 | 357 | moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:pawnColor,p:p})); |
1221ac47 | 358 | } |
1d184b4c BA |
359 | }); |
360 | } | |
361 | ||
362 | // En passant | |
363 | const Lep = this.epSquares.length; | |
0b7d99ec | 364 | const epSquare = (Lep>0 ? this.epSquares[Lep-1] : undefined); |
1d184b4c BA |
365 | if (!!epSquare && epSquare.x == x+shift && Math.abs(epSquare.y - y) == 1) |
366 | { | |
0b7d99ec BA |
367 | const epStep = epSquare.y - y; |
368 | let enpassantMove = this.getBasicMove([x,y], [x+shift,y+epStep]); | |
1d184b4c BA |
369 | enpassantMove.vanish.push({ |
370 | x: x, | |
371 | y: y+epStep, | |
372 | p: 'p', | |
373 | c: this.getColor(x,y+epStep) | |
374 | }); | |
375 | moves.push(enpassantMove); | |
376 | } | |
377 | ||
378 | return moves; | |
379 | } | |
380 | ||
381 | // What are the rook moves from square x,y ? | |
46302e64 | 382 | getPotentialRookMoves(sq) |
1d184b4c | 383 | { |
0b7d99ec | 384 | return this.getSlideNJumpMoves(sq, V.steps[V.ROOK]); |
1d184b4c BA |
385 | } |
386 | ||
387 | // What are the knight moves from square x,y ? | |
46302e64 | 388 | getPotentialKnightMoves(sq) |
1d184b4c | 389 | { |
0b7d99ec | 390 | return this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep"); |
1d184b4c BA |
391 | } |
392 | ||
393 | // What are the bishop moves from square x,y ? | |
46302e64 | 394 | getPotentialBishopMoves(sq) |
1d184b4c | 395 | { |
0b7d99ec | 396 | return this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]); |
1d184b4c BA |
397 | } |
398 | ||
399 | // What are the queen moves from square x,y ? | |
46302e64 | 400 | getPotentialQueenMoves(sq) |
1d184b4c | 401 | { |
a37076f1 | 402 | return this.getSlideNJumpMoves(sq, V.steps[V.ROOK].concat(V.steps[V.BISHOP])); |
1d184b4c BA |
403 | } |
404 | ||
405 | // What are the king moves from square x,y ? | |
46302e64 | 406 | getPotentialKingMoves(sq) |
1d184b4c BA |
407 | { |
408 | // Initialize with normal moves | |
a37076f1 BA |
409 | let moves = this.getSlideNJumpMoves(sq, |
410 | V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep"); | |
46302e64 | 411 | return moves.concat(this.getCastleMoves(sq)); |
1d184b4c BA |
412 | } |
413 | ||
46302e64 | 414 | getCastleMoves([x,y]) |
1d184b4c | 415 | { |
46302e64 | 416 | const c = this.getColor(x,y); |
0b7d99ec | 417 | if (x != (c=="w" ? V.size.x-1 : 0) || y != this.INIT_COL_KING[c]) |
1d184b4c BA |
418 | return []; //x isn't first rank, or king has moved (shortcut) |
419 | ||
1d184b4c BA |
420 | // Castling ? |
421 | const oppCol = this.getOppCol(c); | |
422 | let moves = []; | |
423 | let i = 0; | |
0b7d99ec | 424 | const finalSquares = [ [2,3], [V.size.y-2,V.size.y-3] ]; //king, then rook |
1d184b4c BA |
425 | castlingCheck: |
426 | for (let castleSide=0; castleSide < 2; castleSide++) //large, then small | |
427 | { | |
2526c041 | 428 | if (!this.castleFlags[c][castleSide]) |
1d184b4c BA |
429 | continue; |
430 | // If this code is reached, rooks and king are on initial position | |
431 | ||
432 | // Nothing on the path of the king (and no checks; OK also if y==finalSquare)? | |
433 | let step = finalSquares[castleSide][0] < y ? -1 : 1; | |
434 | for (i=y; i!=finalSquares[castleSide][0]; i+=step) | |
435 | { | |
cf130369 | 436 | if (this.isAttacked([x,i], [oppCol]) || (this.board[x][i] != V.EMPTY && |
1d184b4c BA |
437 | // NOTE: next check is enough, because of chessboard constraints |
438 | (this.getColor(x,i) != c || ![V.KING,V.ROOK].includes(this.getPiece(x,i))))) | |
439 | { | |
440 | continue castlingCheck; | |
441 | } | |
442 | } | |
443 | ||
444 | // Nothing on the path to the rook? | |
445 | step = castleSide == 0 ? -1 : 1; | |
446 | for (i = y + step; i != this.INIT_COL_ROOK[c][castleSide]; i += step) | |
447 | { | |
448 | if (this.board[x][i] != V.EMPTY) | |
449 | continue castlingCheck; | |
450 | } | |
451 | const rookPos = this.INIT_COL_ROOK[c][castleSide]; | |
452 | ||
453 | // Nothing on final squares, except maybe king and castling rook? | |
454 | for (i=0; i<2; i++) | |
455 | { | |
456 | if (this.board[x][finalSquares[castleSide][i]] != V.EMPTY && | |
457 | this.getPiece(x,finalSquares[castleSide][i]) != V.KING && | |
458 | finalSquares[castleSide][i] != rookPos) | |
459 | { | |
460 | continue castlingCheck; | |
461 | } | |
462 | } | |
463 | ||
464 | // If this code is reached, castle is valid | |
465 | moves.push( new Move({ | |
466 | appear: [ | |
467 | new PiPo({x:x,y:finalSquares[castleSide][0],p:V.KING,c:c}), | |
468 | new PiPo({x:x,y:finalSquares[castleSide][1],p:V.ROOK,c:c})], | |
469 | vanish: [ | |
470 | new PiPo({x:x,y:y,p:V.KING,c:c}), | |
471 | new PiPo({x:x,y:rookPos,p:V.ROOK,c:c})], | |
472 | end: Math.abs(y - rookPos) <= 2 | |
473 | ? {x:x, y:rookPos} | |
474 | : {x:x, y:y + 2 * (castleSide==0 ? -1 : 1)} | |
475 | }) ); | |
476 | } | |
477 | ||
478 | return moves; | |
479 | } | |
480 | ||
481 | /////////////////// | |
482 | // MOVES VALIDATION | |
483 | ||
46302e64 | 484 | canIplay(side, [x,y]) |
1d184b4c | 485 | { |
92342261 BA |
486 | return ((side=='w' && this.moves.length%2==0) |
487 | || (side=='b' && this.moves.length%2==1)) | |
46302e64 | 488 | && this.getColor(x,y) == side; |
1d184b4c BA |
489 | } |
490 | ||
491 | getPossibleMovesFrom(sq) | |
492 | { | |
493 | // Assuming color is right (already checked) | |
494 | return this.filterValid( this.getPotentialMovesFrom(sq) ); | |
495 | } | |
496 | ||
92342261 | 497 | // TODO: promotions (into R,B,N,Q) should be filtered only once |
1d184b4c BA |
498 | filterValid(moves) |
499 | { | |
500 | if (moves.length == 0) | |
501 | return []; | |
b8121223 | 502 | return moves.filter(m => { return !this.underCheck(m); }); |
1d184b4c BA |
503 | } |
504 | ||
505 | // Search for all valid moves considering current turn (for engine and game end) | |
46302e64 | 506 | getAllValidMoves() |
1d184b4c | 507 | { |
46302e64 | 508 | const color = this.turn; |
1d184b4c | 509 | const oppCol = this.getOppCol(color); |
c6052161 | 510 | let potentialMoves = []; |
0b7d99ec | 511 | for (let i=0; i<V.size.x; i++) |
1d184b4c | 512 | { |
0b7d99ec | 513 | for (let j=0; j<V.size.y; j++) |
1d184b4c | 514 | { |
92342261 | 515 | // Next condition "!= oppCol" = harmless hack to work with checkered variant |
0b7d99ec | 516 | if (this.board[i][j] != V.EMPTY && this.getColor(i,j) != oppCol) |
1d184b4c BA |
517 | Array.prototype.push.apply(potentialMoves, this.getPotentialMovesFrom([i,j])); |
518 | } | |
519 | } | |
520 | // NOTE: prefer lazy undercheck tests, letting the king being taken? | |
521 | // No: if happen on last 1/2 move, could lead to forbidden moves, wrong evals | |
522 | return this.filterValid(potentialMoves); | |
523 | } | |
9de73b71 | 524 | |
e64a4eff | 525 | // Stop at the first move found |
46302e64 | 526 | atLeastOneMove() |
e64a4eff | 527 | { |
46302e64 | 528 | const color = this.turn; |
e64a4eff | 529 | const oppCol = this.getOppCol(color); |
0b7d99ec | 530 | for (let i=0; i<V.size.x; i++) |
e64a4eff | 531 | { |
0b7d99ec | 532 | for (let j=0; j<V.size.y; j++) |
e64a4eff | 533 | { |
0b7d99ec | 534 | if (this.board[i][j] != V.EMPTY && this.getColor(i,j) != oppCol) |
e64a4eff BA |
535 | { |
536 | const moves = this.getPotentialMovesFrom([i,j]); | |
537 | if (moves.length > 0) | |
538 | { | |
9de73b71 | 539 | for (let k=0; k<moves.length; k++) |
e64a4eff | 540 | { |
9de73b71 | 541 | if (this.filterValid([moves[k]]).length > 0) |
e64a4eff BA |
542 | return true; |
543 | } | |
544 | } | |
545 | } | |
546 | } | |
547 | } | |
548 | return false; | |
549 | } | |
1d184b4c | 550 | |
dda21a71 | 551 | // Check if pieces of color in array 'colors' are attacking square x,y |
46302e64 | 552 | isAttacked(sq, colors) |
1d184b4c | 553 | { |
46302e64 BA |
554 | return (this.isAttackedByPawn(sq, colors) |
555 | || this.isAttackedByRook(sq, colors) | |
556 | || this.isAttackedByKnight(sq, colors) | |
557 | || this.isAttackedByBishop(sq, colors) | |
558 | || this.isAttackedByQueen(sq, colors) | |
559 | || this.isAttackedByKing(sq, colors)); | |
1d184b4c BA |
560 | } |
561 | ||
dda21a71 | 562 | // Is square x,y attacked by 'colors' pawns ? |
46302e64 | 563 | isAttackedByPawn([x,y], colors) |
1d184b4c | 564 | { |
46302e64 | 565 | for (let c of colors) |
1d184b4c | 566 | { |
46302e64 | 567 | let pawnShift = (c=="w" ? 1 : -1); |
0b7d99ec | 568 | if (x+pawnShift>=0 && x+pawnShift<V.size.x) |
1d184b4c | 569 | { |
46302e64 | 570 | for (let i of [-1,1]) |
1d184b4c | 571 | { |
0b7d99ec | 572 | if (y+i>=0 && y+i<V.size.y && this.getPiece(x+pawnShift,y+i)==V.PAWN |
46302e64 BA |
573 | && this.getColor(x+pawnShift,y+i)==c) |
574 | { | |
575 | return true; | |
576 | } | |
1d184b4c BA |
577 | } |
578 | } | |
579 | } | |
580 | return false; | |
581 | } | |
582 | ||
dda21a71 | 583 | // Is square x,y attacked by 'colors' rooks ? |
46302e64 | 584 | isAttackedByRook(sq, colors) |
1d184b4c | 585 | { |
0b7d99ec | 586 | return this.isAttackedBySlideNJump(sq, colors, V.ROOK, V.steps[V.ROOK]); |
1d184b4c BA |
587 | } |
588 | ||
dda21a71 | 589 | // Is square x,y attacked by 'colors' knights ? |
46302e64 | 590 | isAttackedByKnight(sq, colors) |
1d184b4c | 591 | { |
46302e64 | 592 | return this.isAttackedBySlideNJump(sq, colors, |
0b7d99ec | 593 | V.KNIGHT, V.steps[V.KNIGHT], "oneStep"); |
1d184b4c BA |
594 | } |
595 | ||
dda21a71 | 596 | // Is square x,y attacked by 'colors' bishops ? |
46302e64 | 597 | isAttackedByBishop(sq, colors) |
1d184b4c | 598 | { |
0b7d99ec | 599 | return this.isAttackedBySlideNJump(sq, colors, V.BISHOP, V.steps[V.BISHOP]); |
1d184b4c BA |
600 | } |
601 | ||
dda21a71 | 602 | // Is square x,y attacked by 'colors' queens ? |
46302e64 | 603 | isAttackedByQueen(sq, colors) |
1d184b4c | 604 | { |
a37076f1 BA |
605 | return this.isAttackedBySlideNJump(sq, colors, V.QUEEN, |
606 | V.steps[V.ROOK].concat(V.steps[V.BISHOP])); | |
1d184b4c BA |
607 | } |
608 | ||
dda21a71 | 609 | // Is square x,y attacked by 'colors' king(s) ? |
46302e64 | 610 | isAttackedByKing(sq, colors) |
1d184b4c | 611 | { |
a37076f1 BA |
612 | return this.isAttackedBySlideNJump(sq, colors, V.KING, |
613 | V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep"); | |
1d184b4c BA |
614 | } |
615 | ||
1221ac47 | 616 | // Generic method for non-pawn pieces ("sliding or jumping"): |
dda21a71 | 617 | // is x,y attacked by a piece of color in array 'colors' ? |
46302e64 | 618 | isAttackedBySlideNJump([x,y], colors, piece, steps, oneStep) |
1d184b4c BA |
619 | { |
620 | for (let step of steps) | |
621 | { | |
622 | let rx = x+step[0], ry = y+step[1]; | |
0b7d99ec | 623 | while (V.OnBoard(rx,ry) && this.board[rx][ry] == V.EMPTY && !oneStep) |
1d184b4c BA |
624 | { |
625 | rx += step[0]; | |
626 | ry += step[1]; | |
627 | } | |
0b7d99ec BA |
628 | if (V.OnBoard(rx,ry) && this.getPiece(rx,ry) === piece |
629 | && colors.includes(this.getColor(rx,ry))) | |
1d184b4c BA |
630 | { |
631 | return true; | |
632 | } | |
633 | } | |
634 | return false; | |
635 | } | |
636 | ||
dda21a71 | 637 | // Is current player under check after his move ? |
46302e64 | 638 | underCheck(move) |
1d184b4c | 639 | { |
46302e64 | 640 | const color = this.turn; |
1d184b4c | 641 | this.play(move); |
cf130369 | 642 | let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)]); |
1d184b4c BA |
643 | this.undo(move); |
644 | return res; | |
645 | } | |
646 | ||
dda21a71 | 647 | // On which squares is opponent under check after our move ? |
46302e64 | 648 | getCheckSquares(move) |
4b5fe306 BA |
649 | { |
650 | this.play(move); | |
204e289b | 651 | const color = this.turn; //opponent |
cf130369 | 652 | let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)]) |
46302e64 | 653 | ? [ JSON.parse(JSON.stringify(this.kingPos[color])) ] //need to duplicate! |
4b5fe306 BA |
654 | : [ ]; |
655 | this.undo(move); | |
656 | return res; | |
657 | } | |
658 | ||
1d184b4c BA |
659 | // Apply a move on board |
660 | static PlayOnBoard(board, move) | |
661 | { | |
662 | for (let psq of move.vanish) | |
0b7d99ec | 663 | board[psq.x][psq.y] = V.EMPTY; |
1d184b4c BA |
664 | for (let psq of move.appear) |
665 | board[psq.x][psq.y] = psq.c + psq.p; | |
666 | } | |
667 | // Un-apply the played move | |
668 | static UndoOnBoard(board, move) | |
669 | { | |
670 | for (let psq of move.appear) | |
0b7d99ec | 671 | board[psq.x][psq.y] = V.EMPTY; |
1d184b4c BA |
672 | for (let psq of move.vanish) |
673 | board[psq.x][psq.y] = psq.c + psq.p; | |
674 | } | |
675 | ||
d3334c3a | 676 | // Before move is played, update variables + flags |
1d184b4c BA |
677 | updateVariables(move) |
678 | { | |
679 | const piece = this.getPiece(move.start.x,move.start.y); | |
0b7d99ec BA |
680 | const c = this.turn; |
681 | const firstRank = (c == "w" ? V.size.x-1 : 0); | |
1d184b4c BA |
682 | |
683 | // Update king position + flags | |
0b7d99ec | 684 | if (piece == V.KING && move.appear.length > 0) |
1d184b4c BA |
685 | { |
686 | this.kingPos[c][0] = move.appear[0].x; | |
687 | this.kingPos[c][1] = move.appear[0].y; | |
2526c041 | 688 | this.castleFlags[c] = [false,false]; |
1d184b4c BA |
689 | return; |
690 | } | |
691 | const oppCol = this.getOppCol(c); | |
0b7d99ec | 692 | const oppFirstRank = (V.size.x-1) - firstRank; |
1d184b4c BA |
693 | if (move.start.x == firstRank //our rook moves? |
694 | && this.INIT_COL_ROOK[c].includes(move.start.y)) | |
695 | { | |
2526c041 BA |
696 | const flagIdx = (move.start.y == this.INIT_COL_ROOK[c][0] ? 0 : 1); |
697 | this.castleFlags[c][flagIdx] = false; | |
1d184b4c BA |
698 | } |
699 | else if (move.end.x == oppFirstRank //we took opponent rook? | |
aea1443e | 700 | && this.INIT_COL_ROOK[oppCol].includes(move.end.y)) |
1d184b4c | 701 | { |
2526c041 BA |
702 | const flagIdx = (move.end.y == this.INIT_COL_ROOK[oppCol][0] ? 0 : 1); |
703 | this.castleFlags[oppCol][flagIdx] = false; | |
1d184b4c BA |
704 | } |
705 | } | |
706 | ||
dda21a71 BA |
707 | // After move is undo-ed, un-update variables (flags are reset) |
708 | // TODO: more symmetry, by storing flags increment in move... | |
d3334c3a | 709 | unupdateVariables(move) |
1d184b4c | 710 | { |
d3334c3a BA |
711 | // (Potentially) Reset king position |
712 | const c = this.getColor(move.start.x,move.start.y); | |
0b7d99ec | 713 | if (this.getPiece(move.start.x,move.start.y) == V.KING) |
d3334c3a BA |
714 | this.kingPos[c] = [move.start.x, move.start.y]; |
715 | } | |
1d184b4c | 716 | |
15c1295a BA |
717 | // Hash of position+flags+turn after a move is played (to detect repetitions) |
718 | getHashState() | |
331fc58c | 719 | { |
15c1295a | 720 | return hex_md5(this.getFen() + " " + this.turn); |
331fc58c BA |
721 | } |
722 | ||
d3334c3a BA |
723 | play(move, ingame) |
724 | { | |
a3c86ec9 BA |
725 | // DEBUG: |
726 | // if (!this.states) this.states = []; | |
727 | // if (!ingame) this.states.push(JSON.stringify(this.board)); | |
728 | ||
dfb4afc1 | 729 | if (!!ingame) |
6752407b | 730 | move.notation = [this.getNotation(move), this.getLongNotation(move)]; |
dfb4afc1 | 731 | |
2526c041 | 732 | move.flags = JSON.stringify(this.flags); //save flags (for undo) |
d3334c3a BA |
733 | this.updateVariables(move); |
734 | this.moves.push(move); | |
1d184b4c | 735 | this.epSquares.push( this.getEpSquare(move) ); |
0b7d99ec | 736 | V.PlayOnBoard(this.board, move); |
331fc58c BA |
737 | |
738 | if (!!ingame) | |
15c1295a | 739 | move.hash = this.getHashState(); |
1d184b4c BA |
740 | } |
741 | ||
cd4cad04 | 742 | undo(move) |
1d184b4c | 743 | { |
0b7d99ec | 744 | V.UndoOnBoard(this.board, move); |
1d184b4c | 745 | this.epSquares.pop(); |
d3334c3a BA |
746 | this.moves.pop(); |
747 | this.unupdateVariables(move); | |
2526c041 | 748 | this.parseFlags(JSON.parse(move.flags)); |
a3c86ec9 BA |
749 | |
750 | // DEBUG: | |
751 | // if (JSON.stringify(this.board) != this.states[this.states.length-1]) | |
752 | // debugger; | |
753 | // this.states.pop(); | |
1d184b4c BA |
754 | } |
755 | ||
756 | ////////////// | |
757 | // END OF GAME | |
758 | ||
331fc58c | 759 | // Check for 3 repetitions (position + flags + turn) |
1af36beb | 760 | checkRepetition() |
1d184b4c | 761 | { |
15c1295a BA |
762 | if (!this.hashStates) |
763 | this.hashStates = {}; | |
764 | const startIndex = | |
765 | Object.values(this.hashStates).reduce((a,b) => { return a+b; }, 0) | |
766 | // Update this.hashStates with last move (or all moves if continuation) | |
767 | // NOTE: redundant storage, but faster and moderate size | |
768 | for (let i=startIndex; i<this.moves.length; i++) | |
769 | { | |
770 | const move = this.moves[i]; | |
771 | if (!this.hashStates[move.hash]) | |
772 | this.hashStates[move.hash] = 1; | |
773 | else | |
774 | this.hashStates[move.hash]++; | |
775 | } | |
331fc58c | 776 | return Object.values(this.hashStates).some(elt => { return (elt >= 3); }); |
1af36beb | 777 | } |
1d184b4c | 778 | |
dda21a71 | 779 | // Is game over ? And if yes, what is the score ? |
1af36beb BA |
780 | checkGameOver() |
781 | { | |
782 | if (this.checkRepetition()) | |
783 | return "1/2"; | |
784 | ||
785 | if (this.atLeastOneMove()) // game not over | |
1d184b4c | 786 | return "*"; |
1d184b4c BA |
787 | |
788 | // Game over | |
46302e64 | 789 | return this.checkGameEnd(); |
1d184b4c BA |
790 | } |
791 | ||
46302e64 BA |
792 | // No moves are possible: compute score |
793 | checkGameEnd() | |
1d184b4c | 794 | { |
46302e64 | 795 | const color = this.turn; |
1d184b4c | 796 | // No valid move: stalemate or checkmate? |
cf130369 | 797 | if (!this.isAttacked(this.kingPos[color], [this.getOppCol(color)])) |
1d184b4c BA |
798 | return "1/2"; |
799 | // OK, checkmate | |
800 | return color == "w" ? "0-1" : "1-0"; | |
801 | } | |
802 | ||
803 | //////// | |
804 | //ENGINE | |
805 | ||
806 | // Pieces values | |
807 | static get VALUES() { | |
808 | return { | |
809 | 'p': 1, | |
810 | 'r': 5, | |
811 | 'n': 3, | |
812 | 'b': 3, | |
813 | 'q': 9, | |
814 | 'k': 1000 | |
815 | }; | |
816 | } | |
817 | ||
9e42b4dd BA |
818 | static get INFINITY() { |
819 | return 9999; //"checkmate" (unreachable eval) | |
820 | } | |
821 | ||
822 | static get THRESHOLD_MATE() { | |
823 | // At this value or above, the game is over | |
0b7d99ec | 824 | return V.INFINITY; |
9e42b4dd BA |
825 | } |
826 | ||
3c09dc49 BA |
827 | static get SEARCH_DEPTH() { |
828 | return 3; //2 for high branching factor, 4 for small (Loser chess) | |
829 | } | |
830 | ||
1d184b4c | 831 | // Assumption: at least one legal move |
a6abf094 BA |
832 | // NOTE: works also for extinction chess because depth is 3... |
833 | getComputerMove() | |
1d184b4c | 834 | { |
0b7d99ec | 835 | const maxeval = V.INFINITY; |
46302e64 | 836 | const color = this.turn; |
15952ada BA |
837 | // Some variants may show a bigger moves list to the human (Switching), |
838 | // thus the argument "computer" below (which is generally ignored) | |
839 | let moves1 = this.getAllValidMoves("computer"); | |
a6abf094 BA |
840 | |
841 | // Can I mate in 1 ? (for Magnetic & Extinction) | |
842 | for (let i of _.shuffle(_.range(moves1.length))) | |
843 | { | |
844 | this.play(moves1[i]); | |
0b7d99ec BA |
845 | let finish = (Math.abs(this.evalPosition()) >= V.THRESHOLD_MATE); |
846 | if (!finish && !this.atLeastOneMove()) | |
847 | { | |
848 | // Try mate (for other variants) | |
849 | const score = this.checkGameEnd(); | |
850 | if (score != "1/2") | |
851 | finish = true; | |
852 | } | |
a6abf094 BA |
853 | this.undo(moves1[i]); |
854 | if (finish) | |
855 | return moves1[i]; | |
856 | } | |
1d184b4c | 857 | |
06ddfe34 | 858 | // Rank moves using a min-max at depth 2 |
1d184b4c BA |
859 | for (let i=0; i<moves1.length; i++) |
860 | { | |
9e42b4dd | 861 | moves1[i].eval = (color=="w" ? -1 : 1) * maxeval; //very low, I'm checkmated |
1d184b4c | 862 | this.play(moves1[i]); |
68f5ccc8 BA |
863 | let eval2 = undefined; |
864 | if (this.atLeastOneMove()) | |
1d184b4c | 865 | { |
68f5ccc8 BA |
866 | eval2 = (color=="w" ? 1 : -1) * maxeval; //initialized with checkmate value |
867 | // Second half-move: | |
15952ada | 868 | let moves2 = this.getAllValidMoves("computer"); |
68f5ccc8 BA |
869 | for (let j=0; j<moves2.length; j++) |
870 | { | |
871 | this.play(moves2[j]); | |
872 | let evalPos = undefined; | |
873 | if (this.atLeastOneMove()) | |
874 | evalPos = this.evalPosition() | |
875 | else | |
876 | { | |
877 | // Work with scores for Loser variant | |
878 | const score = this.checkGameEnd(); | |
879 | evalPos = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval); | |
880 | } | |
881 | if ((color == "w" && evalPos < eval2) || (color=="b" && evalPos > eval2)) | |
882 | eval2 = evalPos; | |
883 | this.undo(moves2[j]); | |
884 | } | |
885 | } | |
886 | else | |
887 | { | |
888 | const score = this.checkGameEnd(); | |
889 | eval2 = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval); | |
1d184b4c | 890 | } |
92342261 BA |
891 | if ((color=="w" && eval2 > moves1[i].eval) |
892 | || (color=="b" && eval2 < moves1[i].eval)) | |
893 | { | |
1d184b4c | 894 | moves1[i].eval = eval2; |
92342261 | 895 | } |
1d184b4c BA |
896 | this.undo(moves1[i]); |
897 | } | |
898 | moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); }); | |
11a31682 | 899 | //console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; })); |
1d184b4c | 900 | |
3c09dc49 BA |
901 | let candidates = [0]; //indices of candidates moves |
902 | for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++) | |
903 | candidates.push(j); | |
904 | let currentBest = moves1[_.sample(candidates, 1)]; | |
905 | ||
e82cd979 BA |
906 | // From here, depth >= 3: may take a while, so we control time |
907 | const timeStart = Date.now(); | |
908 | ||
a6abf094 | 909 | // Skip depth 3+ if we found a checkmate (or if we are checkmated in 1...) |
0b7d99ec | 910 | if (V.SEARCH_DEPTH >= 3 && Math.abs(moves1[0].eval) < V.THRESHOLD_MATE) |
e64a4eff | 911 | { |
9e42b4dd BA |
912 | for (let i=0; i<moves1.length; i++) |
913 | { | |
e82cd979 BA |
914 | if (Date.now()-timeStart >= 5000) //more than 5 seconds |
915 | return currentBest; //depth 2 at least | |
9e42b4dd BA |
916 | this.play(moves1[i]); |
917 | // 0.1 * oldEval : heuristic to avoid some bad moves (not all...) | |
3c09dc49 | 918 | moves1[i].eval = 0.1*moves1[i].eval + |
0b7d99ec | 919 | this.alphabeta(V.SEARCH_DEPTH-1, -maxeval, maxeval); |
9e42b4dd BA |
920 | this.undo(moves1[i]); |
921 | } | |
922 | moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); }); | |
e64a4eff | 923 | } |
3c09dc49 BA |
924 | else |
925 | return currentBest; | |
68f5ccc8 | 926 | //console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; })); |
1d184b4c | 927 | |
3c09dc49 | 928 | candidates = [0]; |
1d184b4c BA |
929 | for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++) |
930 | candidates.push(j); | |
1d184b4c BA |
931 | return moves1[_.sample(candidates, 1)]; |
932 | } | |
933 | ||
46302e64 | 934 | alphabeta(depth, alpha, beta) |
1d184b4c | 935 | { |
0b7d99ec | 936 | const maxeval = V.INFINITY; |
46302e64 BA |
937 | const color = this.turn; |
938 | if (!this.atLeastOneMove()) | |
1d184b4c | 939 | { |
46302e64 | 940 | switch (this.checkGameEnd()) |
1d184b4c | 941 | { |
68f5ccc8 BA |
942 | case "1/2": |
943 | return 0; | |
944 | default: | |
945 | const score = this.checkGameEnd(); | |
946 | return (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval); | |
1d184b4c BA |
947 | } |
948 | } | |
949 | if (depth == 0) | |
950 | return this.evalPosition(); | |
15952ada | 951 | const moves = this.getAllValidMoves("computer"); |
9e42b4dd | 952 | let v = color=="w" ? -maxeval : maxeval; |
1d184b4c BA |
953 | if (color == "w") |
954 | { | |
955 | for (let i=0; i<moves.length; i++) | |
956 | { | |
957 | this.play(moves[i]); | |
46302e64 | 958 | v = Math.max(v, this.alphabeta(depth-1, alpha, beta)); |
1d184b4c BA |
959 | this.undo(moves[i]); |
960 | alpha = Math.max(alpha, v); | |
961 | if (alpha >= beta) | |
962 | break; //beta cutoff | |
963 | } | |
964 | } | |
965 | else //color=="b" | |
966 | { | |
967 | for (let i=0; i<moves.length; i++) | |
968 | { | |
969 | this.play(moves[i]); | |
46302e64 | 970 | v = Math.min(v, this.alphabeta(depth-1, alpha, beta)); |
1d184b4c BA |
971 | this.undo(moves[i]); |
972 | beta = Math.min(beta, v); | |
973 | if (alpha >= beta) | |
974 | break; //alpha cutoff | |
975 | } | |
976 | } | |
977 | return v; | |
978 | } | |
979 | ||
980 | evalPosition() | |
981 | { | |
1d184b4c | 982 | let evaluation = 0; |
a6abf094 | 983 | // Just count material for now |
0b7d99ec | 984 | for (let i=0; i<V.size.x; i++) |
1d184b4c | 985 | { |
0b7d99ec | 986 | for (let j=0; j<V.size.y; j++) |
1d184b4c | 987 | { |
0b7d99ec | 988 | if (this.board[i][j] != V.EMPTY) |
1d184b4c BA |
989 | { |
990 | const sign = this.getColor(i,j) == "w" ? 1 : -1; | |
0b7d99ec | 991 | evaluation += sign * V.VALUES[this.getPiece(i,j)]; |
1d184b4c BA |
992 | } |
993 | } | |
994 | } | |
995 | return evaluation; | |
996 | } | |
997 | ||
998 | //////////// | |
999 | // FEN utils | |
1000 | ||
dda21a71 | 1001 | // Setup the initial random (assymetric) position |
1d184b4c BA |
1002 | static GenRandInitFen() |
1003 | { | |
32cfcea4 | 1004 | let pieces = { "w": new Array(8), "b": new Array(8) }; |
1d184b4c | 1005 | // Shuffle pieces on first and last rank |
32cfcea4 | 1006 | for (let c of ["w","b"]) |
1d184b4c BA |
1007 | { |
1008 | let positions = _.range(8); | |
1009 | ||
1010 | // Get random squares for bishops | |
1011 | let randIndex = 2 * _.random(3); | |
1012 | let bishop1Pos = positions[randIndex]; | |
1013 | // The second bishop must be on a square of different color | |
1014 | let randIndex_tmp = 2 * _.random(3) + 1; | |
1015 | let bishop2Pos = positions[randIndex_tmp]; | |
1016 | // Remove chosen squares | |
1017 | positions.splice(Math.max(randIndex,randIndex_tmp), 1); | |
1018 | positions.splice(Math.min(randIndex,randIndex_tmp), 1); | |
1019 | ||
1020 | // Get random squares for knights | |
1021 | randIndex = _.random(5); | |
1022 | let knight1Pos = positions[randIndex]; | |
1023 | positions.splice(randIndex, 1); | |
1024 | randIndex = _.random(4); | |
1025 | let knight2Pos = positions[randIndex]; | |
1026 | positions.splice(randIndex, 1); | |
1027 | ||
1028 | // Get random square for queen | |
1029 | randIndex = _.random(3); | |
1030 | let queenPos = positions[randIndex]; | |
1031 | positions.splice(randIndex, 1); | |
1032 | ||
1033 | // Rooks and king positions are now fixed, because of the ordering rook-king-rook | |
1034 | let rook1Pos = positions[0]; | |
1035 | let kingPos = positions[1]; | |
1036 | let rook2Pos = positions[2]; | |
1037 | ||
1038 | // Finally put the shuffled pieces in the board array | |
1039 | pieces[c][rook1Pos] = 'r'; | |
1040 | pieces[c][knight1Pos] = 'n'; | |
1041 | pieces[c][bishop1Pos] = 'b'; | |
1042 | pieces[c][queenPos] = 'q'; | |
1043 | pieces[c][kingPos] = 'k'; | |
1044 | pieces[c][bishop2Pos] = 'b'; | |
1045 | pieces[c][knight2Pos] = 'n'; | |
1046 | pieces[c][rook2Pos] = 'r'; | |
1047 | } | |
2eef6db6 | 1048 | return pieces["b"].join("") + |
1d184b4c | 1049 | "/pppppppp/8/8/8/8/PPPPPPPP/" + |
32cfcea4 | 1050 | pieces["w"].join("").toUpperCase() + |
f3802fcd | 1051 | " 1111"; //add flags |
1d184b4c BA |
1052 | } |
1053 | ||
1054 | // Return current fen according to pieces+colors state | |
1055 | getFen() | |
1056 | { | |
f3802fcd | 1057 | return this.getBaseFen() + " " + this.getFlagsFen(); |
1d184b4c BA |
1058 | } |
1059 | ||
dda21a71 | 1060 | // Position part of the FEN string |
1d184b4c BA |
1061 | getBaseFen() |
1062 | { | |
1063 | let fen = ""; | |
0b7d99ec | 1064 | for (let i=0; i<V.size.x; i++) |
1d184b4c BA |
1065 | { |
1066 | let emptyCount = 0; | |
0b7d99ec | 1067 | for (let j=0; j<V.size.y; j++) |
1d184b4c | 1068 | { |
0b7d99ec | 1069 | if (this.board[i][j] == V.EMPTY) |
1d184b4c BA |
1070 | emptyCount++; |
1071 | else | |
1072 | { | |
1073 | if (emptyCount > 0) | |
1074 | { | |
1075 | // Add empty squares in-between | |
1076 | fen += emptyCount; | |
1077 | emptyCount = 0; | |
1078 | } | |
0b7d99ec | 1079 | fen += V.board2fen(this.board[i][j]); |
1d184b4c BA |
1080 | } |
1081 | } | |
1082 | if (emptyCount > 0) | |
1083 | { | |
1084 | // "Flush remainder" | |
1085 | fen += emptyCount; | |
1086 | } | |
0b7d99ec | 1087 | if (i < V.size.x - 1) |
1d184b4c BA |
1088 | fen += "/"; //separate rows |
1089 | } | |
1090 | return fen; | |
1091 | } | |
1092 | ||
dda21a71 | 1093 | // Flags part of the FEN string |
1d184b4c BA |
1094 | getFlagsFen() |
1095 | { | |
1096 | let fen = ""; | |
1097 | // Add castling flags | |
1098 | for (let i of ['w','b']) | |
1099 | { | |
1100 | for (let j=0; j<2; j++) | |
77e1ec78 | 1101 | fen += (this.castleFlags[i][j] ? '1' : '0'); |
1d184b4c BA |
1102 | } |
1103 | return fen; | |
1104 | } | |
1105 | ||
1106 | // Context: just before move is played, turn hasn't changed | |
1107 | getNotation(move) | |
1108 | { | |
0b7d99ec | 1109 | if (move.appear.length == 2 && move.appear[0].p == V.KING) //castle |
15952ada | 1110 | return (move.end.y < move.start.y ? "0-0-0" : "0-0"); |
1d184b4c BA |
1111 | |
1112 | // Translate final square | |
0b7d99ec | 1113 | const finalSquare = String.fromCharCode(97 + move.end.y) + (V.size.x-move.end.x); |
1d184b4c | 1114 | |
270968d6 | 1115 | const piece = this.getPiece(move.start.x, move.start.y); |
0b7d99ec | 1116 | if (piece == V.PAWN) |
1d184b4c BA |
1117 | { |
1118 | // Pawn move | |
1119 | let notation = ""; | |
5bfb0956 | 1120 | if (move.vanish.length > move.appear.length) |
1d184b4c BA |
1121 | { |
1122 | // Capture | |
270968d6 | 1123 | const startColumn = String.fromCharCode(97 + move.start.y); |
1d184b4c BA |
1124 | notation = startColumn + "x" + finalSquare; |
1125 | } | |
1126 | else //no capture | |
1127 | notation = finalSquare; | |
1128 | if (move.appear.length > 0 && piece != move.appear[0].p) //promotion | |
1129 | notation += "=" + move.appear[0].p.toUpperCase(); | |
1130 | return notation; | |
1131 | } | |
1132 | ||
1133 | else | |
1134 | { | |
1135 | // Piece movement | |
f3c10e18 BA |
1136 | return piece.toUpperCase() + |
1137 | (move.vanish.length > move.appear.length ? "x" : "") + finalSquare; | |
1d184b4c BA |
1138 | } |
1139 | } | |
dfb4afc1 | 1140 | |
6752407b BA |
1141 | // Complete the usual notation, may be required for de-ambiguification |
1142 | getLongNotation(move) | |
1143 | { | |
1144 | const startSquare = | |
0b7d99ec BA |
1145 | String.fromCharCode(97 + move.start.y) + (V.size.x-move.start.x); |
1146 | const finalSquare = String.fromCharCode(97 + move.end.y) + (V.size.x-move.end.x); | |
6752407b BA |
1147 | return startSquare + finalSquare; //not encoding move. But short+long is enough |
1148 | } | |
1149 | ||
dfb4afc1 | 1150 | // The score is already computed when calling this function |
01a135e2 | 1151 | getPGN(mycolor, score, fenStart, mode) |
dfb4afc1 | 1152 | { |
16984853 | 1153 | const zeroPad = x => { return (x<10 ? "0" : "") + x; }; |
dfb4afc1 BA |
1154 | let pgn = ""; |
1155 | pgn += '[Site "vchess.club"]<br>'; | |
1156 | const d = new Date(); | |
5e622704 | 1157 | const opponent = mode=="human" ? "Anonymous" : "Computer"; |
0f51ef98 | 1158 | pgn += '[Variant "' + variant + '"]<br>'; |
92342261 BA |
1159 | pgn += '[Date "' + d.getFullYear() + '-' + (d.getMonth()+1) + |
1160 | '-' + zeroPad(d.getDate()) + '"]<br>'; | |
01a135e2 BA |
1161 | pgn += '[White "' + (mycolor=='w'?'Myself':opponent) + '"]<br>'; |
1162 | pgn += '[Black "' + (mycolor=='b'?'Myself':opponent) + '"]<br>'; | |
04449c97 BA |
1163 | pgn += '[FenStart "' + fenStart + '"]<br>'; |
1164 | pgn += '[Fen "' + this.getFen() + '"]<br>'; | |
762b7c9c | 1165 | pgn += '[Result "' + score + '"]<br><br>'; |
dfb4afc1 | 1166 | |
6752407b | 1167 | // Standard PGN |
dfb4afc1 BA |
1168 | for (let i=0; i<this.moves.length; i++) |
1169 | { | |
1170 | if (i % 2 == 0) | |
1171 | pgn += ((i/2)+1) + "."; | |
6752407b | 1172 | pgn += this.moves[i].notation[0] + " "; |
dfb4afc1 | 1173 | } |
97fc8bf7 | 1174 | pgn += "<br><br>"; |
dfb4afc1 | 1175 | |
6752407b BA |
1176 | // "Complete moves" PGN (helping in ambiguous cases) |
1177 | for (let i=0; i<this.moves.length; i++) | |
1178 | { | |
1179 | if (i % 2 == 0) | |
1180 | pgn += ((i/2)+1) + "."; | |
1181 | pgn += this.moves[i].notation[1] + " "; | |
1182 | } | |
6752407b | 1183 | |
dfb4afc1 BA |
1184 | return pgn; |
1185 | } | |
1d184b4c | 1186 | } |