public/javascripts/variants/Alice.js

   1 // NOTE: alternative implementation, probably cleaner = use only 1 board
   2 class AliceRules extends ChessRules
   3 {
   4     static get ALICE_PIECES()
   5     {
   6         return {
   7             's': 'p',
   8             't': 'q',
   9             'u': 'r',
  10             'c': 'b',
  11             'o': 'n',
  12             'l': 'k',
  13         };
  14     }
  15     static get ALICE_CODES()
  16     {
  17         return {
  18             'p': 's',
  19             'q': 't',
  20             'r': 'u',
  21             'b': 'c',
  22             'n': 'o',
  23             'k': 'l',
  24         };
  25     }
  26
  27     static getPpath(b)
  28     {
  29         return (Object.keys(this.ALICE_PIECES).includes(b[1]) ? "Alice/" : "") + b;
  30     }
  31
  32     static get PIECES()
  33     {
  34         return ChessRules.PIECES.concat(Object.keys(V.ALICE_PIECES));
  35     }
  36
  37     setOtherVariables(fen)
  38     {
  39         super.setOtherVariables(fen);
  40         const rows = V.ParseFen(fen).position.split("/");
  41         if (this.kingPos["w"][0] < 0 || this.kingPos["b"][0] < 0)
  42         {
  43             // INIT_COL_XXX won't be required if Alice kings are found (means 'king moved')
  44             for (let i=0; i<rows.length; i++)
  45             {
  46                 let k = 0; //column index on board
  47                 for (let j=0; j<rows[i].length; j++)
  48                 {
  49                     switch (rows[i].charAt(j))
  50                     {
  51                         case 'l':
  52                             this.kingPos['b'] = [i,k];
  53                             break;
  54                         case 'L':
  55                             this.kingPos['w'] = [i,k];
  56                             break;
  57                         default:
  58                             const num = parseInt(rows[i].charAt(j));
  59                             if (!isNaN(num))
  60                                 k += (num-1);
  61                     }
  62                     k++;
  63                 }
  64             }
  65         }
  66     }
  67
  68     // Return the (standard) color+piece notation at a square for a board
  69     getSquareOccupation(i, j, mirrorSide)
  70     {
  71         const piece = this.getPiece(i,j);
  72         if (mirrorSide==1 && Object.keys(V.ALICE_CODES).includes(piece))
  73             return this.board[i][j];
  74         else if (mirrorSide==2 && Object.keys(V.ALICE_PIECES).includes(piece))
  75             return this.getColor(i,j) + V.ALICE_PIECES[piece];
  76         return "";
  77     }
  78
  79     // Build board of the given (mirror)side
  80     getSideBoard(mirrorSide)
  81     {
  82         // Build corresponding board from complete board
  83         let sideBoard = doubleArray(V.size.x, V.size.y, "");
  84         for (let i=0; i<V.size.x; i++)
  85         {
  86             for (let j=0; j<V.size.y; j++)
  87                 sideBoard[i][j] = this.getSquareOccupation(i, j, mirrorSide);
  88         }
  89         return sideBoard;
  90     }
  91
  92     // NOTE: castle & enPassant https://www.chessvariants.com/other.dir/alice.html
  93     getPotentialMovesFrom([x,y], sideBoard)
  94     {
  95         const pieces = Object.keys(V.ALICE_CODES);
  96         const codes = Object.keys(V.ALICE_PIECES);
  97         const mirrorSide = (pieces.includes(this.getPiece(x,y)) ? 1 : 2);
  98
  99         // Search valid moves on sideBoard
 100         let saveBoard = this.board;
 101         this.board = sideBoard || this.getSideBoard(mirrorSide);
 102         let moves = super.getPotentialMovesFrom([x,y]);
 103         this.board = saveBoard;
 104
 105         // Finally filter impossible moves
 106         let res = moves.filter(m => {
 107             if (m.appear.length == 2) //castle
 108             {
 109                 // appear[i] must be an empty square on the other board
 110                 for (let psq of m.appear)
 111                 {
 112                     if (this.getSquareOccupation(psq.x,psq.y,3-mirrorSide) != V.EMPTY)
 113                         return false;
 114                 }
 115             }
 116             else if (this.board[m.end.x][m.end.y] != V.EMPTY)
 117             {
 118                 // Attempt to capture
 119                 const piece = this.getPiece(m.end.x,m.end.y);
 120                 if ((mirrorSide==1 && codes.includes(piece))
 121                     || (mirrorSide==2 && pieces.includes(piece)))
 122                 {
 123                     return false;
 124                 }
 125             }
 126             // If the move is computed on board1, m.appear change for Alice pieces.
 127             if (mirrorSide==1)
 128             {
 129                 m.appear.forEach(psq => { //forEach: castling taken into account
 130                     psq.p = V.ALICE_CODES[psq.p]; //goto board2
 131                 });
 132             }
 133             else //move on board2: mark vanishing pieces as Alice
 134             {
 135                 m.vanish.forEach(psq => {
 136                     psq.p = V.ALICE_CODES[psq.p];
 137                 });
 138             }
 139             // Fix en-passant captures
 140             if (m.vanish[0].p == V.PAWN && m.vanish.length == 2
 141                 && this.board[m.end.x][m.end.y] == V.EMPTY)
 142             {
 143                 m.vanish[1].c = this.getOppCol(this.getColor(x,y));
 144                 // In the special case of en-passant, if
 145                 //  - board1 takes board2 : vanish[1] --> Alice
 146                 //  - board2 takes board1 : vanish[1] --> normal
 147                 let van = m.vanish[1];
 148                 if (mirrorSide==1 && codes.includes(this.getPiece(van.x,van.y)))
 149                     van.p = V.ALICE_CODES[van.p];
 150                 else if (mirrorSide==2 && pieces.includes(this.getPiece(van.x,van.y)))
 151                     van.p = V.ALICE_PIECES[van.p];
 152             }
 153             return true;
 154         });
 155         return res;
 156     }
 157
 158     filterValid(moves)
 159     {
 160         if (moves.length == 0)
 161             return [];
 162         let sideBoard = [this.getSideBoard(1), this.getSideBoard(2)];
 163         const color = this.turn;
 164         return moves.filter(m => {
 165             this.playSide(m, sideBoard); //no need to track flags
 166             const res = !this.underCheck(color, sideBoard);
 167             this.undoSide(m, sideBoard);
 168             return res;
 169         });
 170     }
 171
 172     getAllValidMoves()
 173     {
 174         const color = this.turn;
 175         const oppCol = this.getOppCol(color);
 176         var potentialMoves = [];
 177         let sideBoard = [this.getSideBoard(1), this.getSideBoard(2)];
 178         for (var i=0; i<V.size.x; i++)
 179         {
 180             for (var j=0; j<V.size.y; j++)
 181             {
 182                 if (this.board[i][j] != V.EMPTY && this.getColor(i,j) == color)
 183                 {
 184                     const mirrorSide =
 185                         Object.keys(V.ALICE_CODES).includes(this.getPiece(i,j))
 186                             ? 1
 187                             : 2;
 188                     Array.prototype.push.apply(potentialMoves,
 189                         this.getPotentialMovesFrom([i,j], sideBoard[mirrorSide-1]));
 190                 }
 191             }
 192         }
 193         return this.filterValid(potentialMoves, sideBoard);
 194     }
 195
 196     // Play on sideboards [TODO: only one sideBoard required]
 197     playSide(move, sideBoard)
 198     {
 199         const pieces = Object.keys(V.ALICE_CODES);
 200         move.vanish.forEach(psq => {
 201             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 202             sideBoard[mirrorSide-1][psq.x][psq.y] = V.EMPTY;
 203         });
 204         move.appear.forEach(psq => {
 205             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 206             const piece = (mirrorSide == 1 ? psq.p : V.ALICE_PIECES[psq.p]);
 207             sideBoard[mirrorSide-1][psq.x][psq.y] = psq.c + piece;
 208             if (piece == V.KING)
 209                 this.kingPos[psq.c] = [psq.x,psq.y];
 210         });
 211     }
 212
 213     // Undo on sideboards
 214     undoSide(move, sideBoard)
 215     {
 216         const pieces = Object.keys(V.ALICE_CODES);
 217         move.appear.forEach(psq => {
 218             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 219             sideBoard[mirrorSide-1][psq.x][psq.y] = V.EMPTY;
 220         });
 221         move.vanish.forEach(psq => {
 222             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 223             const piece = (mirrorSide == 1 ? psq.p : V.ALICE_PIECES[psq.p]);
 224             sideBoard[mirrorSide-1][psq.x][psq.y] = psq.c + piece;
 225             if (piece == V.KING)
 226                 this.kingPos[psq.c] = [psq.x,psq.y];
 227         });
 228     }
 229
 230     underCheck(color, sideBoard) //sideBoard arg always provided
 231     {
 232         const kp = this.kingPos[color];
 233         const mirrorSide = (sideBoard[0][kp[0]][kp[1]] != V.EMPTY ? 1 : 2);
 234         let saveBoard = this.board;
 235         this.board = sideBoard[mirrorSide-1];
 236         let res = this.isAttacked(kp, [this.getOppCol(color)]);
 237         this.board = saveBoard;
 238         return res;
 239     }
 240
 241     getCheckSquares(color)
 242     {
 243         const pieces = Object.keys(V.ALICE_CODES);
 244         const kp = this.kingPos[color];
 245         const mirrorSide = (pieces.includes(this.getPiece(kp[0],kp[1])) ? 1 : 2);
 246         let sideBoard = this.getSideBoard(mirrorSide);
 247         let saveBoard = this.board;
 248         this.board = sideBoard;
 249         let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)])
 250             ? [ JSON.parse(JSON.stringify(this.kingPos[color])) ]
 251             : [ ];
 252         this.board = saveBoard;
 253         return res;
 254     }
 255
 256     updateVariables(move)
 257     {
 258         super.updateVariables(move); //standard king
 259         const piece = move.vanish[0].p;
 260         const c = move.vanish[0].c;
 261         // "l" = Alice king
 262         if (piece == "l")
 263         {
 264             this.kingPos[c][0] = move.appear[0].x;
 265             this.kingPos[c][1] = move.appear[0].y;
 266             this.castleFlags[c] = [false,false];
 267         }
 268     }
 269
 270     unupdateVariables(move)
 271     {
 272         super.unupdateVariables(move);
 273         const c = move.vanish[0].c;
 274         if (move.vanish[0].p == "l")
 275             this.kingPos[c] = [move.start.x, move.start.y];
 276     }
 277
 278     checkGameEnd()
 279     {
 280         const pieces = Object.keys(V.ALICE_CODES);
 281         const color = this.turn;
 282         const kp = this.kingPos[color];
 283         const mirrorSide = (pieces.includes(this.getPiece(kp[0],kp[1])) ? 1 : 2);
 284         let sideBoard = this.getSideBoard(mirrorSide);
 285         let saveBoard = this.board;
 286         this.board = sideBoard;
 287         let res = "*";
 288         if (!this.isAttacked(this.kingPos[color], [this.getOppCol(color)]))
 289             res = "1/2";
 290         else
 291             res = (color == "w" ? "0-1" : "1-0");
 292         this.board = saveBoard;
 293         return res;
 294     }
 295
 296     static get VALUES()
 297     {
 298         return Object.assign(
 299             ChessRules.VALUES,
 300             {
 301                 's': 1,
 302                 'u': 5,
 303                 'o': 3,
 304                 'c': 3,
 305                 't': 9,
 306                 'l': 1000,
 307             }
 308         );
 309     }
 310
 311     getNotation(move)
 312     {
 313         if (move.appear.length == 2 && move.appear[0].p == V.KING)
 314         {
 315             if (move.end.y < move.start.y)
 316                 return "0-0-0";
 317             else
 318                 return "0-0";
 319         }
 320
 321         const finalSquare = V.CoordsToSquare(move.end);
 322         const piece = this.getPiece(move.start.x, move.start.y);
 323
 324         const captureMark = (move.vanish.length > move.appear.length ? "x" : "");
 325         let pawnMark = "";
 326         if (["p","s"].includes(piece) && captureMark.length == 1)
 327             pawnMark = V.CoordToColumn(move.start.y); //start column
 328
 329         // Piece or pawn movement
 330         let notation = piece.toUpperCase() + pawnMark + captureMark + finalSquare;
 331         if (['s','p'].includes(piece) && !['s','p'].includes(move.appear[0].p))
 332         {
 333             // Promotion
 334             notation += "=" + move.appear[0].p.toUpperCase();
 335         }
 336         return notation;
 337     }
 338 }
 339
 340 const VariantRules = AliceRules;