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