| 1 | class MagneticRules extends ChessRules |
| 2 | { |
| 3 | getEpSquare(move) |
| 4 | { |
| 5 | return undefined; //no en-passant |
| 6 | } |
| 7 | |
| 8 | // Complete a move with magnetic actions |
| 9 | applyMagneticLaws([x,y], move) |
| 10 | { |
| 11 | const standardMove = JSON.parse(JSON.stringify(move)); |
| 12 | this.play(standardMove); |
| 13 | const color = this.getColor(x,y); |
| 14 | const [sizeX,sizeY] = VariantRules.size; |
| 15 | for (let step of [[-1,0],[1,0],[0,-1],[0,1]]) |
| 16 | { |
| 17 | let [i,j] = [x+step[0],y+step[1]]; |
| 18 | while (i>=0 && i<sizeX && j>=0 && j<sizeY) |
| 19 | { |
| 20 | if (this.board[i][j] != VariantRules.EMPTY) |
| 21 | { |
| 22 | // Found something. Same color or not? |
| 23 | if (this.getColor(i,j) != color) |
| 24 | { |
| 25 | // Attraction |
| 26 | if ((Math.abs(i-x)>=2 || Math.abs(j-y)>=2) |
| 27 | && this.getPiece(i,j) != VariantRules.KING) |
| 28 | { |
| 29 | move.vanish.push( |
| 30 | new PiPo({ |
| 31 | p:this.getPiece(i,j), |
| 32 | c:this.getColor(i,j), |
| 33 | x:i, |
| 34 | y:j |
| 35 | }) |
| 36 | ); |
| 37 | move.appear.push( |
| 38 | new PiPo({ |
| 39 | p:this.getPiece(i,j), |
| 40 | c:this.getColor(i,j), |
| 41 | x:x+step[0], |
| 42 | y:y+step[1] |
| 43 | }) |
| 44 | ); |
| 45 | } |
| 46 | } |
| 47 | else |
| 48 | { |
| 49 | // Repulsion |
| 50 | if (this.getPiece(i,j) != VariantRules.KING) |
| 51 | { |
| 52 | // Push it until we meet an obstacle or edge of the board |
| 53 | let [ii,jj] = [i+step[0],j+step[1]]; |
| 54 | while (ii>=0 && ii<sizeX && jj>=0 && jj<sizeY) |
| 55 | { |
| 56 | if (this.board[ii][jj] != VariantRules.EMPTY) |
| 57 | break; |
| 58 | ii += step[0]; |
| 59 | jj += step[1]; |
| 60 | } |
| 61 | ii -= step[0]; |
| 62 | jj -= step[1]; |
| 63 | if (Math.abs(ii-i)>=1 || Math.abs(jj-j)>=1) |
| 64 | { |
| 65 | move.vanish.push( |
| 66 | new PiPo({ |
| 67 | p:this.getPiece(i,j), |
| 68 | c:this.getColor(i,j), |
| 69 | x:i, |
| 70 | y:j |
| 71 | }) |
| 72 | ); |
| 73 | move.appear.push( |
| 74 | new PiPo({ |
| 75 | p:this.getPiece(i,j), |
| 76 | c:this.getColor(i,j), |
| 77 | x:ii, |
| 78 | y:jj |
| 79 | }) |
| 80 | ); |
| 81 | } |
| 82 | } |
| 83 | } |
| 84 | break; |
| 85 | } |
| 86 | i += step[0]; |
| 87 | j += step[1]; |
| 88 | } |
| 89 | } |
| 90 | this.undo(standardMove); |
| 91 | } |
| 92 | |
| 93 | // TODO: when pawn is pushed to 8th rank, apply promotions (similar change as in Checkered) |
| 94 | getBasicMove([sx,sy], [ex,ey], tr) |
| 95 | { |
| 96 | var mv = new Move({ |
| 97 | appear: [ |
| 98 | new PiPo({ |
| 99 | x: ex, |
| 100 | y: ey, |
| 101 | c: !!tr ? tr.c : this.getColor(sx,sy), |
| 102 | p: !!tr ? tr.p : this.getPiece(sx,sy) |
| 103 | }) |
| 104 | ], |
| 105 | vanish: [ |
| 106 | new PiPo({ |
| 107 | x: sx, |
| 108 | y: sy, |
| 109 | c: this.getColor(sx,sy), |
| 110 | p: this.getPiece(sx,sy) |
| 111 | }) |
| 112 | ] |
| 113 | }); |
| 114 | |
| 115 | if (this.board[ex][ey] != VariantRules.EMPTY) |
| 116 | { |
| 117 | mv.vanish.push( |
| 118 | new PiPo({ |
| 119 | x: ex, |
| 120 | y: ey, |
| 121 | c: this.getColor(ex,ey), |
| 122 | p: this.getPiece(ex,ey) |
| 123 | }) |
| 124 | ); |
| 125 | } |
| 126 | this.applyMagneticLaws([ex,ey], mv); |
| 127 | return mv; |
| 128 | } |
| 129 | |
| 130 | getPotentialPawnMoves([x,y]) |
| 131 | { |
| 132 | const color = this.getColor(x,y); |
| 133 | var moves = []; |
| 134 | var V = VariantRules; |
| 135 | const [sizeX,sizeY] = VariantRules.size; |
| 136 | let shift = (color == "w" ? -1 : 1); |
| 137 | let startRank = (color == "w" ? sizeY-2 : 1); |
| 138 | let firstRank = (color == 'w' ? sizeY-1 : 0); |
| 139 | let lastRank = (color == "w" ? 0 : sizeY-1); |
| 140 | |
| 141 | if (x+shift >= 0 && x+shift < sizeX && x+shift != lastRank) |
| 142 | { |
| 143 | // Normal moves |
| 144 | if (this.board[x+shift][y] == V.EMPTY) |
| 145 | { |
| 146 | moves.push(this.getBasicMove([x,y], [x+shift,y])); |
| 147 | if ([startRank,firstRank].includes(x) && this.board[x+2*shift][y] == V.EMPTY) |
| 148 | { |
| 149 | // Two squares jump |
| 150 | moves.push(this.getBasicMove([x,y], [x+2*shift,y])); |
| 151 | } |
| 152 | } |
| 153 | // Captures |
| 154 | if (y>0 && this.canTake([x,y], [x+shift,y-1]) && this.board[x+shift][y-1] != V.EMPTY) |
| 155 | moves.push(this.getBasicMove([x,y], [x+shift,y-1])); |
| 156 | if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1]) && this.board[x+shift][y+1] != V.EMPTY) |
| 157 | moves.push(this.getBasicMove([x,y], [x+shift,y+1])); |
| 158 | } |
| 159 | |
| 160 | if (x+shift == lastRank) |
| 161 | { |
| 162 | // Promotion |
| 163 | let promotionPieces = [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN]; |
| 164 | promotionPieces.forEach(p => { |
| 165 | // Normal move |
| 166 | if (this.board[x+shift][y] == V.EMPTY) |
| 167 | moves.push(this.getBasicMove([x,y], [x+shift,y], {c:color,p:p})); |
| 168 | // Captures |
| 169 | if (y>0 && this.canTake([x,y], [x+shift,y-1]) && this.board[x+shift][y-1] != V.EMPTY) |
| 170 | moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:color,p:p})); |
| 171 | if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1]) && this.board[x+shift][y+1] != V.EMPTY) |
| 172 | moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:color,p:p})); |
| 173 | }); |
| 174 | } |
| 175 | |
| 176 | // No en passant |
| 177 | |
| 178 | return moves; |
| 179 | } |
| 180 | |
| 181 | getCastleMoves([x,y]) |
| 182 | { |
| 183 | const c = this.getColor(x,y); |
| 184 | if (x != (c=="w" ? 7 : 0) || y != this.INIT_COL_KING[c]) |
| 185 | return []; //x isn't first rank, or king has moved (shortcut) |
| 186 | |
| 187 | const V = VariantRules; |
| 188 | |
| 189 | // Castling ? |
| 190 | const oppCol = this.getOppCol(c); |
| 191 | let moves = []; |
| 192 | let i = 0; |
| 193 | const finalSquares = [ [2,3], [6,5] ]; //king, then rook |
| 194 | castlingCheck: |
| 195 | for (let castleSide=0; castleSide < 2; castleSide++) //large, then small |
| 196 | { |
| 197 | if (!this.flags[c][castleSide]) |
| 198 | continue; |
| 199 | // If this code is reached, rooks and king are on initial position |
| 200 | |
| 201 | // Nothing on the path of the king (and no checks; OK also if y==finalSquare)? |
| 202 | let step = finalSquares[castleSide][0] < y ? -1 : 1; |
| 203 | for (i=y; i!=finalSquares[castleSide][0]; i+=step) |
| 204 | { |
| 205 | if (this.isAttacked([x,i], oppCol) || (this.board[x][i] != V.EMPTY && |
| 206 | // NOTE: next check is enough, because of chessboard constraints |
| 207 | (this.getColor(x,i) != c || ![V.KING,V.ROOK].includes(this.getPiece(x,i))))) |
| 208 | { |
| 209 | continue castlingCheck; |
| 210 | } |
| 211 | } |
| 212 | |
| 213 | // Nothing on the path to the rook? |
| 214 | step = castleSide == 0 ? -1 : 1; |
| 215 | for (i = y + step; i != this.INIT_COL_ROOK[c][castleSide]; i += step) |
| 216 | { |
| 217 | if (this.board[x][i] != V.EMPTY) |
| 218 | continue castlingCheck; |
| 219 | } |
| 220 | const rookPos = this.INIT_COL_ROOK[c][castleSide]; |
| 221 | |
| 222 | // Nothing on final squares, except maybe king and castling rook? |
| 223 | for (i=0; i<2; i++) |
| 224 | { |
| 225 | if (this.board[x][finalSquares[castleSide][i]] != V.EMPTY && |
| 226 | this.getPiece(x,finalSquares[castleSide][i]) != V.KING && |
| 227 | finalSquares[castleSide][i] != rookPos) |
| 228 | { |
| 229 | continue castlingCheck; |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | // If this code is reached, castle is valid |
| 234 | let cmove = new Move({ |
| 235 | appear: [ |
| 236 | new PiPo({x:x,y:finalSquares[castleSide][0],p:V.KING,c:c}), |
| 237 | new PiPo({x:x,y:finalSquares[castleSide][1],p:V.ROOK,c:c})], |
| 238 | vanish: [ |
| 239 | new PiPo({x:x,y:y,p:V.KING,c:c}), |
| 240 | new PiPo({x:x,y:rookPos,p:V.ROOK,c:c})], |
| 241 | end: Math.abs(y - rookPos) <= 2 |
| 242 | ? {x:x, y:rookPos} |
| 243 | : {x:x, y:y + 2 * (castleSide==0 ? -1 : 1)} |
| 244 | }); |
| 245 | this.applyMagneticLaws([x,finalSquares[castleSide][1]], cmove); |
| 246 | moves.push(cmove); |
| 247 | } |
| 248 | |
| 249 | return moves; |
| 250 | } |
| 251 | |
| 252 | // TODO: verify this assertion |
| 253 | // atLeastOneMove() |
| 254 | // { |
| 255 | // return true; //always at least one possible move |
| 256 | // } |
| 257 | |
| 258 | underCheck(move) |
| 259 | { |
| 260 | return false; //there is no check |
| 261 | } |
| 262 | |
| 263 | getCheckSquares(move) |
| 264 | { |
| 265 | const c = this.getOppCol(this.turn); //opponent |
| 266 | const saveKingPos = this.kingPos[c]; //king might be taken |
| 267 | this.play(move); |
| 268 | // The only way to be "under check" is to have lost the king (thus game over) |
| 269 | let res = this.kingPos[c][0] < 0 |
| 270 | ? [ JSON.parse(JSON.stringify(saveKingPos)) ] |
| 271 | : [ ]; |
| 272 | this.undo(move); |
| 273 | return res; |
| 274 | } |
| 275 | |
| 276 | updateVariables(move) |
| 277 | { |
| 278 | super.updateVariables(move); |
| 279 | const c = this.getColor(move.start.x,move.start.y); |
| 280 | if (c != this.getColor(move.end.x,move.end.y) |
| 281 | && this.board[move.end.x][move.end.y] != VariantRules.EMPTY |
| 282 | && this.getPiece(move.end.x,move.end.y) == VariantRules.KING) |
| 283 | { |
| 284 | // We took opponent king ! |
| 285 | const oppCol = this.getOppCol(c); |
| 286 | this.kingPos[oppCol] = [-1,-1]; |
| 287 | this.flags[oppCol] = [false,false]; |
| 288 | } |
| 289 | } |
| 290 | |
| 291 | unupdateVariables(move) |
| 292 | { |
| 293 | super.unupdateVariables(move); |
| 294 | const c = this.getColor(move.start.x,move.start.y); |
| 295 | const oppCol = this.getOppCol(c); |
| 296 | if (this.kingPos[oppCol][0] < 0) |
| 297 | { |
| 298 | // Last move took opponent's king |
| 299 | for (let psq of move.vanish) |
| 300 | { |
| 301 | if (psq.p == 'k') |
| 302 | { |
| 303 | this.kingPos[oppCol] = [psq.x, psq.y]; |
| 304 | break; |
| 305 | } |
| 306 | } |
| 307 | } |
| 308 | } |
| 309 | |
| 310 | checkGameOver() |
| 311 | { |
| 312 | if (this.checkRepetition()) |
| 313 | return "1/2"; |
| 314 | |
| 315 | const color = this.turn; |
| 316 | // TODO: do we need "atLeastOneMove()"? |
| 317 | if (this.atLeastOneMove() && this.kingPos[color][0] >= 0) |
| 318 | return "*"; |
| 319 | |
| 320 | return this.checkGameEnd(); |
| 321 | } |
| 322 | |
| 323 | checkGameEnd() |
| 324 | { |
| 325 | // No valid move: our king disappeared |
| 326 | return this.turn == "w" ? "0-1" : "1-0"; |
| 327 | } |
| 328 | } |