| 1 | import { ChessRules, PiPo } from "@/base_rules"; |
| 2 | import { randInt } from "@/utils/alea"; |
| 3 | |
| 4 | export class SwapRules extends ChessRules { |
| 5 | |
| 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) { |
| 38 | if (m.appear.length == 1) return super.getPPpath(m); |
| 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) => { |
| 75 | if (this.getPiece(i, j) != piece || this.getColor(i, j) != color) |
| 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 | |
| 149 | static GenRandInitFen(options) { |
| 150 | // Add empty smove: |
| 151 | return ChessRules.GenRandInitFen(options) + " -"; |
| 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 | |
| 273 | // NOTE: searching best (half) move for opponent turn is a bit too slow. |
| 274 | // => Only 2 half moves depth here. |
| 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]); |
| 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 | } |
| 324 | |
| 325 | }; |