Commit | Line | Data |
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829f6574 | 1 | import { ChessRules } from "@/base_rules"; |
5fde3a01 | 2 | import { randInt } from "@/utils/alea"; |
829f6574 | 3 | |
b406466b | 4 | export class Doublemove2Rules extends ChessRules { |
7e8a7ea1 | 5 | |
6808d7a1 | 6 | static IsGoodEnpassant(enpassant) { |
e71161fb BA |
7 | const squares = enpassant.split(","); |
8 | if (squares.length > 2) return false; | |
9 | for (let sq of squares) { | |
10 | if (sq != "-") { | |
dac39588 | 11 | const ep = V.SquareToCoords(sq); |
6808d7a1 | 12 | if (isNaN(ep.x) || !V.OnBoard(ep)) return false; |
dac39588 BA |
13 | } |
14 | } | |
15 | return true; | |
16 | } | |
6e62b1c7 | 17 | |
dac39588 | 18 | // There may be 2 enPassant squares (if 2 pawns jump 2 squares in same turn) |
6808d7a1 | 19 | getEnpassantFen() { |
e71161fb BA |
20 | return this.epSquares[this.epSquares.length - 1].map( |
21 | epsq => epsq === undefined | |
22 | ? "-" //no en-passant | |
23 | : V.CoordsToSquare(epsq) | |
24 | ).join(","); | |
dac39588 | 25 | } |
6e62b1c7 | 26 | |
6808d7a1 | 27 | setOtherVariables(fen) { |
dac39588 BA |
28 | const parsedFen = V.ParseFen(fen); |
29 | this.setFlags(parsedFen.flags); | |
e71161fb BA |
30 | this.epSquares = [parsedFen.enpassant.split(",").map(sq => { |
31 | if (sq != "-") return V.SquareToCoords(sq); | |
32 | return undefined; | |
33 | })]; | |
3a2a7b5f | 34 | this.scanKings(fen); |
dac39588 BA |
35 | // Extract subTurn from turn indicator: "w" (first move), or |
36 | // "w1" or "w2" white subturn 1 or 2, and same for black | |
af34341d BA |
37 | this.turn = parsedFen.turn; |
38 | this.subTurn = 1; | |
dac39588 | 39 | } |
6e62b1c7 | 40 | |
32f6285e | 41 | getEnpassantCaptures([x, y], shiftX) { |
dac39588 | 42 | let moves = []; |
dac39588 BA |
43 | // En passant: always OK if subturn 1, |
44 | // OK on subturn 2 only if enPassant was played at subturn 1 | |
45 | // (and if there are two e.p. squares available). | |
46 | const Lep = this.epSquares.length; | |
6808d7a1 | 47 | const epSquares = this.epSquares[Lep - 1]; //always at least one element |
dac39588 BA |
48 | let epSqs = []; |
49 | epSquares.forEach(sq => { | |
6808d7a1 | 50 | if (sq) epSqs.push(sq); |
dac39588 | 51 | }); |
6808d7a1 | 52 | if (epSqs.length == 0) return moves; |
32f6285e | 53 | const oppCol = V.GetOppCol(this.getColor(x, y)); |
6808d7a1 BA |
54 | for (let sq of epSqs) { |
55 | if ( | |
56 | this.subTurn == 1 || | |
57 | (epSqs.length == 2 && | |
58 | // Was this en-passant capture already played at subturn 1 ? | |
59 | // (Or maybe the opponent filled the en-passant square with a piece) | |
60 | this.board[epSqs[0].x][epSqs[0].y] != V.EMPTY) | |
61 | ) { | |
62 | if ( | |
63 | sq.x == x + shiftX && | |
64 | Math.abs(sq.y - y) == 1 && | |
dac39588 | 65 | // Add condition "enemy pawn must be present" |
6808d7a1 BA |
66 | this.getPiece(x, sq.y) == V.PAWN && |
67 | this.getColor(x, sq.y) == oppCol | |
68 | ) { | |
69 | let epMove = this.getBasicMove([x, y], [sq.x, sq.y]); | |
dac39588 BA |
70 | epMove.vanish.push({ |
71 | x: x, | |
72 | y: sq.y, | |
6808d7a1 | 73 | p: "p", |
dac39588 BA |
74 | c: oppCol |
75 | }); | |
76 | moves.push(epMove); | |
77 | } | |
78 | } | |
79 | } | |
dac39588 BA |
80 | return moves; |
81 | } | |
6e62b1c7 | 82 | |
34bfe151 | 83 | isAttacked() { |
bc0b9205 | 84 | // Goal is king capture => no checks |
b406466b BA |
85 | return false; |
86 | } | |
87 | ||
88 | filterValid(moves) { | |
bc0b9205 BA |
89 | return moves; |
90 | } | |
91 | ||
92 | getCheckSquares() { | |
93 | return []; | |
94 | } | |
95 | ||
96 | getCurrentScore() { | |
97 | const color = this.turn; | |
98 | if (this.kingPos[color][0] < 0) return (color == 'w' ? "0-1" : "1-0"); | |
99 | return "*"; | |
b406466b BA |
100 | } |
101 | ||
6808d7a1 | 102 | play(move) { |
dac39588 | 103 | move.flags = JSON.stringify(this.aggregateFlags()); |
dac39588 BA |
104 | V.PlayOnBoard(this.board, move); |
105 | const epSq = this.getEpSquare(move); | |
b406466b BA |
106 | if (this.subTurn == 2) { |
107 | let lastEpsq = this.epSquares[this.epSquares.length - 1]; | |
108 | lastEpsq.push(epSq); | |
dac39588 | 109 | this.turn = V.GetOppCol(this.turn); |
b406466b BA |
110 | } |
111 | else { | |
dac39588 | 112 | this.epSquares.push([epSq]); |
9842aca2 | 113 | this.movesCount++; |
964eda04 BA |
114 | if ( |
115 | this.movesCount == 1 || | |
116 | // King is captured at subTurn 1? | |
117 | (move.vanish.length == 2 && move.vanish[1].p == V.KING) | |
118 | ) { | |
119 | this.turn = "b"; | |
120 | } | |
dac39588 | 121 | } |
b406466b | 122 | if (this.movesCount > 1) this.subTurn = 3 - this.subTurn; |
3a2a7b5f BA |
123 | this.postPlay(move); |
124 | } | |
125 | ||
126 | postPlay(move) { | |
b406466b | 127 | const c = move.vanish[0].c; |
3a2a7b5f BA |
128 | const piece = move.vanish[0].p; |
129 | const firstRank = c == "w" ? V.size.x - 1 : 0; | |
130 | ||
737a5daf | 131 | if (piece == V.KING) { |
bc0b9205 | 132 | this.kingPos[c] = [move.appear[0].x, move.appear[0].y]; |
0d5335de | 133 | this.castleFlags[c] = [V.size.y, V.size.y]; |
3a2a7b5f BA |
134 | return; |
135 | } | |
136 | const oppCol = V.GetOppCol(c); | |
964eda04 | 137 | if (move.vanish.length == 2 && move.vanish[1].p == V.KING) { |
bc0b9205 BA |
138 | // Opponent's king is captured, game over |
139 | this.kingPos[oppCol] = [-1, -1]; | |
964eda04 BA |
140 | move.captureKing = true; //for undo |
141 | } | |
3a2a7b5f BA |
142 | const oppFirstRank = V.size.x - 1 - firstRank; |
143 | if ( | |
144 | move.start.x == firstRank && //our rook moves? | |
145 | this.castleFlags[c].includes(move.start.y) | |
146 | ) { | |
147 | const flagIdx = (move.start.y == this.castleFlags[c][0] ? 0 : 1); | |
148 | this.castleFlags[c][flagIdx] = V.size.y; | |
bc0b9205 | 149 | } |
737a5daf | 150 | if ( |
3a2a7b5f BA |
151 | move.end.x == oppFirstRank && //we took opponent rook? |
152 | this.castleFlags[oppCol].includes(move.end.y) | |
153 | ) { | |
154 | const flagIdx = (move.end.y == this.castleFlags[oppCol][0] ? 0 : 1); | |
155 | this.castleFlags[oppCol][flagIdx] = V.size.y; | |
156 | } | |
dac39588 | 157 | } |
6e62b1c7 | 158 | |
6808d7a1 | 159 | undo(move) { |
dac39588 BA |
160 | this.disaggregateFlags(JSON.parse(move.flags)); |
161 | V.UndoOnBoard(this.board, move); | |
964eda04 | 162 | if (this.subTurn == 2 || this.movesCount == 1 || !!move.captureKing) { |
dac39588 | 163 | this.epSquares.pop(); |
9842aca2 | 164 | this.movesCount--; |
b406466b BA |
165 | if (this.movesCount == 0) this.turn = "w"; |
166 | } | |
167 | else { | |
6808d7a1 | 168 | let lastEpsq = this.epSquares[this.epSquares.length - 1]; |
dac39588 | 169 | lastEpsq.pop(); |
b406466b | 170 | this.turn = V.GetOppCol(this.turn); |
dac39588 | 171 | } |
b406466b | 172 | if (this.movesCount > 0) this.subTurn = 3 - this.subTurn; |
bc0b9205 | 173 | this.postUndo(move); |
dac39588 | 174 | } |
6e62b1c7 | 175 | |
bc0b9205 BA |
176 | postUndo(move) { |
177 | if (move.vanish.length == 2 && move.vanish[1].p == V.KING) | |
178 | // Opponent's king was captured | |
179 | this.kingPos[move.vanish[1].c] = [move.vanish[1].x, move.vanish[1].y]; | |
180 | super.postUndo(move); | |
dac39588 | 181 | } |
0596f5e7 | 182 | |
bc0b9205 | 183 | // No alpha-beta here, just adapted min-max at depth 2(+1) |
6808d7a1 | 184 | getComputerMove() { |
bc0b9205 | 185 | const maxeval = V.INFINITY; |
dac39588 | 186 | const color = this.turn; |
bc0b9205 BA |
187 | const oppCol = V.GetOppCol(this.turn); |
188 | ||
189 | // Search best (half) move for opponent turn | |
190 | const getBestMoveEval = () => { | |
191 | let score = this.getCurrentScore(); | |
192 | if (score != "*") return maxeval * (score == "1-0" ? 1 : -1); | |
193 | let moves = this.getAllValidMoves(); | |
194 | let res = oppCol == "w" ? -maxeval : maxeval; | |
195 | for (let m of moves) { | |
196 | this.play(m); | |
197 | score = this.getCurrentScore(); | |
198 | if (score != "*") { | |
199 | // King captured | |
200 | this.undo(m); | |
201 | return maxeval * (score == "1-0" ? 1 : -1); | |
202 | } | |
203 | const evalPos = this.evalPosition(); | |
204 | res = oppCol == "w" ? Math.max(res, evalPos) : Math.min(res, evalPos); | |
205 | this.undo(m); | |
206 | } | |
207 | return res; | |
208 | }; | |
209 | ||
5d75c82c BA |
210 | const moves11 = this.getAllValidMoves(); |
211 | if (this.movesCount == 0) | |
212 | // First white move at random: | |
213 | return moves11[randInt(moves11.length)]; | |
737a5daf BA |
214 | let doubleMove = null; |
215 | let bestEval = Number.POSITIVE_INFINITY * (color == 'w' ? -1 : 1); | |
5d75c82c | 216 | // Rank moves using a min-max at depth 2 |
6808d7a1 | 217 | for (let i = 0; i < moves11.length; i++) { |
dac39588 | 218 | this.play(moves11[i]); |
5d75c82c | 219 | const moves12 = this.getAllValidMoves(); |
b406466b BA |
220 | for (let j = 0; j < moves12.length; j++) { |
221 | this.play(moves12[j]); | |
737a5daf BA |
222 | // Small fluctuations to uniformize play a little |
223 | const evalM = getBestMoveEval() + 0.05 - Math.random() / 10 | |
224 | if ( | |
225 | (color == 'w' && evalM > bestEval) || | |
226 | (color == 'b' && evalM < bestEval) | |
227 | ) { | |
228 | doubleMove = [moves11[i], moves12[j]]; | |
229 | bestEval = evalM; | |
230 | } | |
b406466b | 231 | this.undo(moves12[j]); |
dac39588 BA |
232 | } |
233 | this.undo(moves11[i]); | |
234 | } | |
737a5daf BA |
235 | // TODO: not always the best move played (why ???) |
236 | return doubleMove; | |
dac39588 | 237 | } |
7e8a7ea1 | 238 | |
6808d7a1 | 239 | }; |