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964eda04 BA |
1 | import { ChessRules, PiPo } from "@/base_rules"; |
2 | import { randInt } from "@/utils/alea"; | |
3 | ||
4 | export class SwapRules extends ChessRules { | |
7e8a7ea1 | 5 | |
964eda04 BA |
6 | setOtherVariables(fen) { |
7 | super.setOtherVariables(fen); | |
8 | // Local stack of swaps | |
9 | this.swaps = []; | |
10 | const smove = V.ParseFen(fen).smove; | |
11 | if (smove == "-") this.swaps.push(null); | |
12 | else { | |
13 | this.swaps.push({ | |
14 | start: ChessRules.SquareToCoords(smove.substr(0, 2)), | |
15 | end: ChessRules.SquareToCoords(smove.substr(2)) | |
16 | }); | |
17 | } | |
18 | this.subTurn = 1; | |
19 | } | |
20 | ||
21 | static ParseFen(fen) { | |
22 | return Object.assign( | |
23 | ChessRules.ParseFen(fen), | |
24 | { smove: fen.split(" ")[5] } | |
25 | ); | |
26 | } | |
27 | ||
28 | static IsGoodFen(fen) { | |
29 | if (!ChessRules.IsGoodFen(fen)) return false; | |
30 | const fenParts = fen.split(" "); | |
31 | if (fenParts.length != 6) return false; | |
32 | if (fenParts[5] != "-" && !fenParts[5].match(/^([a-h][1-8]){2}$/)) | |
33 | return false; | |
34 | return true; | |
35 | } | |
36 | ||
37 | getPPpath(m) { | |
1349f848 | 38 | if (m.appear.length == 1) return super.getPPpath(m); |
964eda04 BA |
39 | // Swap promotion: |
40 | return m.appear[1].c + m.appear[1].p; | |
41 | } | |
42 | ||
43 | getSwapMoves([x1, y1], [x2, y2]) { | |
44 | let move = super.getBasicMove([x1, y1], [x2, y2]); | |
45 | move.appear.push( | |
46 | new PiPo({ | |
47 | x: x1, | |
48 | y: y1, | |
49 | c: this.getColor(x2, y2), | |
50 | p: this.getPiece(x2, y2) | |
51 | }) | |
52 | ); | |
53 | const lastRank = (move.appear[1].c == 'w' ? 0 : 7); | |
54 | if (move.appear[1].p == V.PAWN && move.appear[1].x == lastRank) { | |
55 | // Promotion: | |
56 | move.appear[1].p = V.ROOK; | |
57 | let moves = [move]; | |
58 | [V.KNIGHT, V.BISHOP, V.QUEEN].forEach(p => { | |
59 | let m = JSON.parse(JSON.stringify(move)); | |
60 | m.appear[1].p = p; | |
61 | moves.push(m); | |
62 | }); | |
63 | return moves; | |
64 | } | |
65 | return [move]; | |
66 | } | |
67 | ||
68 | getPotentialMovesFrom([x, y]) { | |
69 | if (this.subTurn == 1) return super.getPotentialMovesFrom([x, y]); | |
70 | // SubTurn == 2: only swaps | |
71 | let moves = []; | |
72 | const color = this.turn; | |
73 | const piece = this.getPiece(x, y); | |
74 | const addSmoves = (i, j) => { | |
0e0ffddd | 75 | if (this.getPiece(i, j) != piece || this.getColor(i, j) != color) |
964eda04 BA |
76 | Array.prototype.push.apply(moves, this.getSwapMoves([x, y], [i, j])); |
77 | }; | |
78 | switch (piece) { | |
79 | case V.PAWN: { | |
80 | const forward = (color == 'w' ? -1 : 1); | |
81 | const startRank = (color == 'w' ? [6, 7] : [0, 1]); | |
82 | if ( | |
83 | x == startRank && | |
84 | this.board[x + forward][y] == V.EMPTY && | |
85 | this.board[x + 2 * forward][y] != V.EMPTY | |
86 | ) { | |
87 | // Swap using 2 squares move | |
88 | addSmoves(x + 2 * forward, y); | |
89 | } | |
90 | for (let shift of [-1, 0, 1]) { | |
91 | const [i, j] = [x + forward, y + shift]; | |
92 | if (V.OnBoard(i, j) && this.board[i][j] != V.EMPTY) addSmoves(i, j); | |
93 | } | |
94 | break; | |
95 | } | |
96 | case V.KNIGHT: | |
97 | V.steps[V.KNIGHT].forEach(s => { | |
98 | const [i, j] = [x + s[0], y + s[1]]; | |
99 | if (V.OnBoard(i, j) && this.board[i][j] != V.EMPTY) addSmoves(i, j); | |
100 | }); | |
101 | break; | |
102 | case V.KING: | |
103 | V.steps[V.ROOK].concat(V.steps[V.BISHOP]).forEach(s => { | |
104 | const [i, j] = [x + s[0], y + s[1]]; | |
105 | if (V.OnBoard(i, j) && this.board[i][j] != V.EMPTY) addSmoves(i, j); | |
106 | }); | |
107 | break; | |
108 | case V.ROOK: | |
109 | case V.BISHOP: | |
110 | case V.QUEEN: { | |
111 | const steps = | |
112 | piece != V.QUEEN | |
113 | ? V.steps[piece] | |
114 | : V.steps[V.ROOK].concat(V.steps[V.BISHOP]); | |
115 | steps.forEach(s => { | |
116 | let [i, j] = [x + s[0], y + s[1]]; | |
117 | while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) { | |
118 | i += s[0]; | |
119 | j += s[1]; | |
120 | } | |
121 | if (V.OnBoard(i, j) && this.board[i][j] != V.EMPTY) addSmoves(i, j); | |
122 | }); | |
123 | break; | |
124 | } | |
125 | } | |
126 | return moves; | |
127 | } | |
128 | ||
129 | // Does m2 un-do m1 ? (to disallow undoing swaps) | |
130 | oppositeSwaps(m1, m2) { | |
131 | return ( | |
132 | !!m1 && | |
133 | m1.start.x == m2.start.x && | |
134 | m1.end.x == m2.end.x && | |
135 | m1.start.y == m2.start.y && | |
136 | m1.end.y == m2.end.y | |
137 | ); | |
138 | } | |
139 | ||
140 | filterValid(moves) { | |
141 | const fmoves = super.filterValid(moves); | |
142 | if (this.subTurn == 1) return fmoves; | |
143 | return fmoves.filter(m => { | |
144 | const L = this.swaps.length; //at least 1: init from FEN | |
145 | return !this.oppositeSwaps(this.swaps[L - 1], m); | |
146 | }); | |
147 | } | |
148 | ||
4313762d | 149 | static GenRandInitFen(options) { |
964eda04 | 150 | // Add empty smove: |
4313762d | 151 | return ChessRules.GenRandInitFen(options) + " -"; |
964eda04 BA |
152 | } |
153 | ||
154 | getSmoveFen() { | |
155 | const L = this.swaps.length; | |
156 | return ( | |
157 | !this.swaps[L - 1] | |
158 | ? "-" | |
159 | : ChessRules.CoordsToSquare(this.swaps[L - 1].start) + | |
160 | ChessRules.CoordsToSquare(this.swaps[L - 1].end) | |
161 | ); | |
162 | } | |
163 | ||
164 | getFen() { | |
165 | return super.getFen() + " " + this.getSmoveFen(); | |
166 | } | |
167 | ||
168 | getFenForRepeat() { | |
169 | return super.getFenForRepeat() + "_" + this.getSmoveFen(); | |
170 | } | |
171 | ||
172 | getCurrentScore() { | |
173 | const L = this.swaps.length; | |
174 | if (this.movesCount >= 2 && !this.swaps[L-1]) | |
175 | // Opponent had no swap moves: I win | |
176 | return (this.turn == "w" ? "1-0" : "0-1"); | |
177 | if (this.atLeastOneMove()) return "*"; | |
178 | // No valid move: I lose | |
179 | return (this.turn == "w" ? "0-1" : "1-0"); | |
180 | } | |
181 | ||
182 | noSwapAfter(move) { | |
183 | this.subTurn = 2; | |
184 | const res = !this.atLeastOneMove(); | |
185 | this.subTurn = 1; | |
186 | return res; | |
187 | } | |
188 | ||
189 | play(move) { | |
190 | move.flags = JSON.stringify(this.aggregateFlags()); | |
191 | move.turn = [this.turn, this.subTurn]; | |
192 | V.PlayOnBoard(this.board, move); | |
193 | let epSq = undefined; | |
194 | if (this.subTurn == 1) epSq = this.getEpSquare(move); | |
195 | if (this.movesCount == 0) { | |
196 | // First move in game | |
197 | this.turn = "b"; | |
198 | this.epSquares.push(epSq); | |
199 | this.movesCount = 1; | |
200 | } | |
201 | // Any swap available after move? If no, skip subturn 2 | |
202 | else if (this.subTurn == 1 && this.noSwapAfter(move)) { | |
203 | this.turn = V.GetOppCol(this.turn); | |
204 | this.epSquares.push(epSq); | |
205 | move.noSwap = true; | |
206 | this.movesCount++; | |
207 | } | |
208 | else { | |
209 | if (this.subTurn == 2) { | |
210 | this.turn = V.GetOppCol(this.turn); | |
211 | this.swaps.push({ start: move.start, end: move.end }); | |
212 | } | |
213 | else { | |
214 | this.epSquares.push(epSq); | |
215 | this.movesCount++; | |
216 | } | |
217 | this.subTurn = 3 - this.subTurn; | |
218 | } | |
219 | this.postPlay(move); | |
220 | } | |
221 | ||
222 | postPlay(move) { | |
223 | const firstRank = { 7: 'w', 0: 'b' }; | |
224 | // Did some king move? | |
225 | move.appear.forEach(a => { | |
226 | if (a.p == V.KING) { | |
227 | this.kingPos[a.c] = [a.x, a.y]; | |
228 | this.castleFlags[a.c] = [V.size.y, V.size.y]; | |
229 | } | |
230 | }); | |
231 | for (let coords of [move.start, move.end]) { | |
232 | if ( | |
233 | Object.keys(firstRank).includes(coords.x) && | |
234 | this.castleFlags[firstRank[coords.x]].includes(coords.y) | |
235 | ) { | |
236 | const c = firstRank[coords.x]; | |
237 | const flagIdx = (coords.y == this.castleFlags[c][0] ? 0 : 1); | |
238 | this.castleFlags[c][flagIdx] = V.size.y; | |
239 | } | |
240 | } | |
241 | } | |
242 | ||
243 | undo(move) { | |
244 | this.disaggregateFlags(JSON.parse(move.flags)); | |
245 | V.UndoOnBoard(this.board, move); | |
246 | if (move.turn[1] == 1) { | |
247 | // The move may not be full, but is fully undone: | |
248 | this.epSquares.pop(); | |
249 | // Moves counter was just incremented: | |
250 | this.movesCount--; | |
251 | } | |
252 | else | |
253 | // Undo the second half of a move | |
254 | this.swaps.pop(); | |
255 | this.turn = move.turn[0]; | |
256 | this.subTurn = move.turn[1]; | |
257 | this.postUndo(move); | |
258 | } | |
259 | ||
260 | postUndo(move) { | |
261 | // Did some king move? | |
262 | move.vanish.forEach(v => { | |
263 | if (v.p == V.KING) this.kingPos[v.c] = [v.x, v.y]; | |
264 | }); | |
265 | } | |
266 | ||
267 | // No alpha-beta here, just adapted min-max at depth 2(+1) | |
268 | getComputerMove() { | |
269 | const maxeval = V.INFINITY; | |
270 | const color = this.turn; | |
271 | const oppCol = V.GetOppCol(this.turn); | |
272 | ||
f52671e5 BA |
273 | // NOTE: searching best (half) move for opponent turn is a bit too slow. |
274 | // => Only 2 half moves depth here. | |
964eda04 BA |
275 | |
276 | const moves11 = this.getAllValidMoves(); | |
277 | if (this.movesCount == 0) | |
278 | // Just play first move at random: | |
279 | return moves11[randInt(moves11.length)]; | |
280 | let bestMove = undefined; | |
281 | // Rank moves using a min-max at depth 2 | |
282 | for (let i = 0; i < moves11.length; i++) { | |
283 | this.play(moves11[i]); | |
284 | if (!!moves11[i].noSwap) { | |
285 | // I lose | |
286 | if (!bestMove) bestMove = { | |
287 | moves: moves11[i], | |
288 | eval: (color == 'w' ? -maxeval : maxeval) | |
289 | }; | |
290 | } | |
291 | else { | |
292 | let moves12 = this.getAllValidMoves(); | |
293 | for (let j = 0; j < moves12.length; j++) { | |
294 | this.play(moves12[j]); | |
964eda04 BA |
295 | const evalMove = this.evalPosition() + 0.05 - Math.random() / 10; |
296 | if ( | |
297 | !bestMove || | |
298 | (color == 'w' && evalMove > bestMove.eval) || | |
299 | (color == 'b' && evalMove < bestMove.eval) | |
300 | ) { | |
301 | bestMove = { | |
302 | moves: [moves11[i], moves12[j]], | |
303 | eval: evalMove | |
304 | }; | |
305 | } | |
306 | this.undo(moves12[j]); | |
307 | } | |
308 | } | |
309 | this.undo(moves11[i]); | |
310 | } | |
311 | return bestMove.moves; | |
312 | } | |
313 | ||
314 | getNotation(move) { | |
315 | if (move.appear.length == 1) | |
316 | // Normal move | |
317 | return super.getNotation(move); | |
318 | if (move.appear[0].p == V.KING && move.appear[1].p == V.ROOK) | |
319 | // Castle | |
320 | return (move.end.y < move.start.y ? "0-0-0" : "0-0"); | |
321 | // Swap | |
322 | return "S" + V.CoordsToSquare(move.start) + V.CoordsToSquare(move.end); | |
323 | } | |
7e8a7ea1 | 324 | |
964eda04 | 325 | }; |