| 1 | // TODO: to detect oppositeMoves, we need last move --> encoded in FEN |
| 2 | // + local moves stack (for AlphaBeta) + lastMove (in FEN) |
| 3 | |
| 4 | import { ChessRules } from "@/base_rules"; |
| 5 | |
| 6 | export const VariantRules = class CheckeredRules extends ChessRules |
| 7 | { |
| 8 | static getPpath(b) |
| 9 | { |
| 10 | return b[0]=='c' ? "Checkered/"+b : b; |
| 11 | } |
| 12 | |
| 13 | static board2fen(b) |
| 14 | { |
| 15 | const checkered_codes = { |
| 16 | 'p': 's', |
| 17 | 'q': 't', |
| 18 | 'r': 'u', |
| 19 | 'b': 'c', |
| 20 | 'n': 'o', |
| 21 | }; |
| 22 | if (b[0]=="c") |
| 23 | return checkered_codes[b[1]]; |
| 24 | return ChessRules.board2fen(b); |
| 25 | } |
| 26 | |
| 27 | static fen2board(f) |
| 28 | { |
| 29 | // Tolerate upper-case versions of checkered pieces (why not?) |
| 30 | const checkered_pieces = { |
| 31 | 's': 'p', |
| 32 | 'S': 'p', |
| 33 | 't': 'q', |
| 34 | 'T': 'q', |
| 35 | 'u': 'r', |
| 36 | 'U': 'r', |
| 37 | 'c': 'b', |
| 38 | 'C': 'b', |
| 39 | 'o': 'n', |
| 40 | 'O': 'n', |
| 41 | }; |
| 42 | if (Object.keys(checkered_pieces).includes(f)) |
| 43 | return 'c'+checkered_pieces[f]; |
| 44 | return ChessRules.fen2board(f); |
| 45 | } |
| 46 | |
| 47 | static get PIECES() |
| 48 | { |
| 49 | return ChessRules.PIECES.concat(['s','t','u','c','o']); |
| 50 | } |
| 51 | |
| 52 | static IsGoodFlags(flags) |
| 53 | { |
| 54 | // 4 for castle + 16 for pawns |
| 55 | return !!flags.match(/^[01]{20,20}$/); |
| 56 | } |
| 57 | |
| 58 | setFlags(fenflags) |
| 59 | { |
| 60 | super.setFlags(fenflags); //castleFlags |
| 61 | this.pawnFlags = |
| 62 | { |
| 63 | "w": [...Array(8).fill(true)], //pawns can move 2 squares? |
| 64 | "b": [...Array(8).fill(true)], |
| 65 | }; |
| 66 | if (!fenflags) |
| 67 | return; |
| 68 | const flags = fenflags.substr(4); //skip first 4 digits, for castle |
| 69 | for (let c of ['w','b']) |
| 70 | { |
| 71 | for (let i=0; i<8; i++) |
| 72 | this.pawnFlags[c][i] = (flags.charAt((c=='w'?0:8)+i) == '1'); |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | aggregateFlags() |
| 77 | { |
| 78 | return [this.castleFlags, this.pawnFlags]; |
| 79 | } |
| 80 | |
| 81 | disaggregateFlags(flags) |
| 82 | { |
| 83 | this.castleFlags = flags[0]; |
| 84 | this.pawnFlags = flags[1]; |
| 85 | } |
| 86 | |
| 87 | canTake([x1,y1], [x2,y2]) |
| 88 | { |
| 89 | const color1 = this.getColor(x1,y1); |
| 90 | const color2 = this.getColor(x2,y2); |
| 91 | // Checkered aren't captured |
| 92 | return color1 != color2 && color2 != 'c' && (color1 != 'c' || color2 != this.turn); |
| 93 | } |
| 94 | |
| 95 | // Post-processing: apply "checkerization" of standard moves |
| 96 | getPotentialMovesFrom([x,y]) |
| 97 | { |
| 98 | let standardMoves = super.getPotentialMovesFrom([x,y]); |
| 99 | const lastRank = this.turn == "w" ? 0 : 7; |
| 100 | if (this.getPiece(x,y) == V.KING) |
| 101 | return standardMoves; //king has to be treated differently (for castles) |
| 102 | let moves = []; |
| 103 | standardMoves.forEach(m => { |
| 104 | if (m.vanish[0].p == V.PAWN) |
| 105 | { |
| 106 | if (Math.abs(m.end.x-m.start.x)==2 && !this.pawnFlags[this.turn][m.start.y]) |
| 107 | return; //skip forbidden 2-squares jumps |
| 108 | if (this.board[m.end.x][m.end.y] == V.EMPTY && m.vanish.length==2 |
| 109 | && this.getColor(m.start.x,m.start.y) == 'c') |
| 110 | { |
| 111 | return; //checkered pawns cannot take en-passant |
| 112 | } |
| 113 | } |
| 114 | if (m.vanish.length == 1) |
| 115 | moves.push(m); //no capture |
| 116 | else |
| 117 | { |
| 118 | // A capture occured (m.vanish.length == 2) |
| 119 | m.appear[0].c = "c"; |
| 120 | moves.push(m); |
| 121 | if (m.appear[0].p != m.vanish[1].p //avoid promotions (already treated): |
| 122 | && (m.vanish[0].p != V.PAWN || m.end.x != lastRank)) |
| 123 | { |
| 124 | // Add transformation into captured piece |
| 125 | let m2 = JSON.parse(JSON.stringify(m)); |
| 126 | m2.appear[0].p = m.vanish[1].p; |
| 127 | moves.push(m2); |
| 128 | } |
| 129 | } |
| 130 | }); |
| 131 | return moves; |
| 132 | } |
| 133 | |
| 134 | canIplay(side, [x,y]) |
| 135 | { |
| 136 | return (side == this.turn && [side,'c'].includes(this.getColor(x,y))); |
| 137 | } |
| 138 | |
| 139 | // Does m2 un-do m1 ? (to disallow undoing checkered moves) |
| 140 | oppositeMoves(m1, m2) |
| 141 | { |
| 142 | return m1.appear.length == 1 && m2.appear.length == 1 |
| 143 | && m1.vanish.length == 1 && m2.vanish.length == 1 |
| 144 | && m1.start.x == m2.end.x && m1.end.x == m2.start.x |
| 145 | && m1.start.y == m2.end.y && m1.end.y == m2.start.y |
| 146 | && m1.appear[0].c == m2.vanish[0].c && m1.appear[0].p == m2.vanish[0].p |
| 147 | && m1.vanish[0].c == m2.appear[0].c && m1.vanish[0].p == m2.appear[0].p; |
| 148 | } |
| 149 | |
| 150 | filterValid(moves) |
| 151 | { |
| 152 | if (moves.length == 0) |
| 153 | return []; |
| 154 | const color = this.turn; |
| 155 | return moves.filter(m => { |
| 156 | const L = this.moves.length; |
| 157 | if (L > 0 && this.oppositeMoves(this.moves[L-1], m)) |
| 158 | return false; |
| 159 | this.play(m); |
| 160 | const res = !this.underCheck(color); |
| 161 | this.undo(m); |
| 162 | return res; |
| 163 | }); |
| 164 | } |
| 165 | |
| 166 | isAttackedByPawn([x,y], colors) |
| 167 | { |
| 168 | for (let c of colors) |
| 169 | { |
| 170 | const color = (c=="c" ? this.turn : c); |
| 171 | let pawnShift = (color=="w" ? 1 : -1); |
| 172 | if (x+pawnShift>=0 && x+pawnShift<8) |
| 173 | { |
| 174 | for (let i of [-1,1]) |
| 175 | { |
| 176 | if (y+i>=0 && y+i<8 && this.getPiece(x+pawnShift,y+i)==V.PAWN |
| 177 | && this.getColor(x+pawnShift,y+i)==c) |
| 178 | { |
| 179 | return true; |
| 180 | } |
| 181 | } |
| 182 | } |
| 183 | } |
| 184 | return false; |
| 185 | } |
| 186 | |
| 187 | underCheck(color) |
| 188 | { |
| 189 | return this.isAttacked(this.kingPos[color], [V.GetOppCol(color),'c']); |
| 190 | } |
| 191 | |
| 192 | getCheckSquares(color) |
| 193 | { |
| 194 | // Artifically change turn, for checkered pawns |
| 195 | this.turn = V.GetOppCol(color); |
| 196 | const kingAttacked = this.isAttacked( |
| 197 | this.kingPos[color], [V.GetOppCol(color),'c']); |
| 198 | let res = kingAttacked |
| 199 | ? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate! |
| 200 | : []; |
| 201 | this.turn = color; |
| 202 | return res; |
| 203 | } |
| 204 | |
| 205 | updateVariables(move) |
| 206 | { |
| 207 | super.updateVariables(move); |
| 208 | // Does this move turn off a 2-squares pawn flag? |
| 209 | const secondRank = [1,6]; |
| 210 | if (secondRank.includes(move.start.x) && move.vanish[0].p == V.PAWN) |
| 211 | this.pawnFlags[move.start.x==6 ? "w" : "b"][move.start.y] = false; |
| 212 | } |
| 213 | |
| 214 | getCurrentScore() |
| 215 | { |
| 216 | if (this.atLeastOneMove()) // game not over |
| 217 | return "*"; |
| 218 | |
| 219 | const color = this.turn; |
| 220 | // Artifically change turn, for checkered pawns |
| 221 | this.turn = V.GetOppCol(this.turn); |
| 222 | const res = this.isAttacked(this.kingPos[color], [V.GetOppCol(color),'c']) |
| 223 | ? (color == "w" ? "0-1" : "1-0") |
| 224 | : "1/2"; |
| 225 | this.turn = V.GetOppCol(this.turn); |
| 226 | return res; |
| 227 | } |
| 228 | |
| 229 | evalPosition() |
| 230 | { |
| 231 | let evaluation = 0; |
| 232 | //Just count material for now, considering checkered neutral (...) |
| 233 | for (let i=0; i<V.size.x; i++) |
| 234 | { |
| 235 | for (let j=0; j<V.size.y; j++) |
| 236 | { |
| 237 | if (this.board[i][j] != V.EMPTY) |
| 238 | { |
| 239 | const sqColor = this.getColor(i,j); |
| 240 | const sign = sqColor == "w" ? 1 : (sqColor=="b" ? -1 : 0); |
| 241 | evaluation += sign * V.VALUES[this.getPiece(i,j)]; |
| 242 | } |
| 243 | } |
| 244 | } |
| 245 | return evaluation; |
| 246 | } |
| 247 | |
| 248 | static GenRandInitFen() |
| 249 | { |
| 250 | const randFen = ChessRules.GenRandInitFen(); |
| 251 | // Add 16 pawns flags: |
| 252 | return randFen.replace(" w 0 1111", " w 0 11111111111111111111"); |
| 253 | } |
| 254 | |
| 255 | getFlagsFen() |
| 256 | { |
| 257 | let fen = super.getFlagsFen(); |
| 258 | // Add pawns flags |
| 259 | for (let c of ['w','b']) |
| 260 | { |
| 261 | for (let i=0; i<8; i++) |
| 262 | fen += this.pawnFlags[c][i] ? '1' : '0'; |
| 263 | } |
| 264 | return fen; |
| 265 | } |
| 266 | |
| 267 | getNotation(move) |
| 268 | { |
| 269 | if (move.appear.length == 2) |
| 270 | { |
| 271 | // Castle |
| 272 | if (move.end.y < move.start.y) |
| 273 | return "0-0-0"; |
| 274 | else |
| 275 | return "0-0"; |
| 276 | } |
| 277 | |
| 278 | // Translate final square |
| 279 | const finalSquare = V.CoordsToSquare(move.end); |
| 280 | |
| 281 | const piece = this.getPiece(move.start.x, move.start.y); |
| 282 | if (piece == V.PAWN) |
| 283 | { |
| 284 | // Pawn move |
| 285 | let notation = ""; |
| 286 | if (move.vanish.length > 1) |
| 287 | { |
| 288 | // Capture |
| 289 | const startColumn = V.CoordToColumn(move.start.y); |
| 290 | notation = startColumn + "x" + finalSquare + |
| 291 | "=" + move.appear[0].p.toUpperCase(); |
| 292 | } |
| 293 | else //no capture |
| 294 | { |
| 295 | notation = finalSquare; |
| 296 | if (move.appear.length > 0 && piece != move.appear[0].p) //promotion |
| 297 | notation += "=" + move.appear[0].p.toUpperCase(); |
| 298 | } |
| 299 | return notation; |
| 300 | } |
| 301 | |
| 302 | else |
| 303 | { |
| 304 | // Piece movement |
| 305 | return piece.toUpperCase() + (move.vanish.length > 1 ? "x" : "") + finalSquare |
| 306 | + (move.vanish.length > 1 ? "=" + move.appear[0].p.toUpperCase() : ""); |
| 307 | } |
| 308 | } |
| 309 | } |