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         return ChessRules.PIECES.concat(Object.keys(V.ALICE_PIECES));
  34     }
  35
  36     initVariables(fen)
  37     {
  38         super.initVariables(fen);
  39         const fenParts = fen.split(" ");
  40         const position = fenParts[0].split("/");
  41         if (this.kingPos["w"][0] < 0 || this.kingPos["b"][0] < 0)
  42         {
  43             // INIT_COL_XXX won't be used, so no need to set them for Alice kings
  44             for (let i=0; i<position.length; i++)
  45             {
  46                 let k = 0; //column index on board
  47                 for (let j=0; j<position[i].length; j++)
  48                 {
  49                     switch (position[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                             let num = parseInt(position[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         return moves.filter(m => { return !this.underCheck(m, sideBoard); });
 164     }
 165
 166     getAllValidMoves()
 167     {
 168         const color = this.turn;
 169         const oppCol = this.getOppCol(color);
 170         var potentialMoves = [];
 171         let sideBoard = [this.getSideBoard(1), this.getSideBoard(2)];
 172         for (var i=0; i<V.size.x; i++)
 173         {
 174             for (var j=0; j<V.size.y; j++)
 175             {
 176                 if (this.board[i][j] != V.EMPTY && this.getColor(i,j) == color)
 177                 {
 178                     const mirrorSide =
 179                         Object.keys(V.ALICE_CODES).includes(this.getPiece(i,j))
 180                             ? 1
 181                             : 2;
 182                     Array.prototype.push.apply(potentialMoves,
 183                         this.getPotentialMovesFrom([i,j], sideBoard[mirrorSide-1]));
 184                 }
 185             }
 186         }
 187         return this.filterValid(potentialMoves, sideBoard);
 188     }
 189
 190     // Play on sideboards [TODO: only one sideBoard required]
 191     playSide(move, sideBoard)
 192     {
 193         const pieces = Object.keys(V.ALICE_CODES);
 194         move.vanish.forEach(psq => {
 195             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 196             sideBoard[mirrorSide-1][psq.x][psq.y] = V.EMPTY;
 197         });
 198         move.appear.forEach(psq => {
 199             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 200             const piece = (mirrorSide == 1 ? psq.p : V.ALICE_PIECES[psq.p]);
 201             sideBoard[mirrorSide-1][psq.x][psq.y] = psq.c + piece;
 202             if (piece == V.KING)
 203                 this.kingPos[psq.c] = [psq.x,psq.y];
 204         });
 205     }
 206
 207     // Undo on sideboards
 208     undoSide(move, sideBoard)
 209     {
 210         const pieces = Object.keys(V.ALICE_CODES);
 211         move.appear.forEach(psq => {
 212             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 213             sideBoard[mirrorSide-1][psq.x][psq.y] = V.EMPTY;
 214         });
 215         move.vanish.forEach(psq => {
 216             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 217             const piece = (mirrorSide == 1 ? psq.p : V.ALICE_PIECES[psq.p]);
 218             sideBoard[mirrorSide-1][psq.x][psq.y] = psq.c + piece;
 219             if (piece == V.KING)
 220                 this.kingPos[psq.c] = [psq.x,psq.y];
 221         });
 222     }
 223
 224     underCheck(move, sideBoard) //sideBoard arg always provided
 225     {
 226         const color = this.turn;
 227         this.playSide(move, sideBoard); //no need to track flags
 228         const kp = this.kingPos[color];
 229         const mirrorSide = (sideBoard[0][kp[0]][kp[1]] != V.EMPTY ? 1 : 2);
 230         let saveBoard = this.board;
 231         this.board = sideBoard[mirrorSide-1];
 232         let res = this.isAttacked(kp, [this.getOppCol(color)]);
 233         this.board = saveBoard;
 234         this.undoSide(move, sideBoard);
 235         return res;
 236     }
 237
 238     getCheckSquares(move)
 239     {
 240         this.play(move);
 241         const color = this.turn; //opponent
 242         const pieces = Object.keys(V.ALICE_CODES);
 243         const kp = this.kingPos[color];
 244         const mirrorSide = (pieces.includes(this.getPiece(kp[0],kp[1])) ? 1 : 2);
 245         let sideBoard = this.getSideBoard(mirrorSide);
 246         let saveBoard = this.board;
 247         this.board = sideBoard;
 248         let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)])
 249             ? [ JSON.parse(JSON.stringify(this.kingPos[color])) ]
 250             : [ ];
 251         this.board = saveBoard;
 252         this.undo(move);
 253         return res;
 254     }
 255
 256     updateVariables(move)
 257     {
 258         super.updateVariables(move); //standard king
 259         const piece = this.getPiece(move.start.x,move.start.y);
 260         const c = this.getColor(move.start.x,move.start.y);
 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 = this.getColor(move.start.x,move.start.y);
 274         if (this.getPiece(move.start.x,move.start.y) == "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         return Object.assign(
 298             ChessRules.VALUES,
 299             {
 300                 's': 1,
 301                 'u': 5,
 302                 'o': 3,
 303                 'c': 3,
 304                 't': 9,
 305                 'l': 1000,
 306             }
 307         );
 308     }
 309
 310     getNotation(move)
 311     {
 312         if (move.appear.length == 2 && move.appear[0].p == V.KING)
 313         {
 314             if (move.end.y < move.start.y)
 315                 return "0-0-0";
 316             else
 317                 return "0-0";
 318         }
 319
 320         const finalSquare = String.fromCharCode(97 + move.end.y) + (V.size.x-move.end.x);
 321         const piece = this.getPiece(move.start.x, move.start.y);
 322
 323         const captureMark = (move.vanish.length > move.appear.length ? "x" : "");
 324         let pawnMark = "";
 325         if (["p","s"].includes(piece) && captureMark.length == 1)
 326             pawnMark = String.fromCharCode(97 + move.start.y); //start column
 327
 328         // Piece or pawn movement
 329         let notation = piece.toUpperCase() + pawnMark + captureMark + finalSquare;
 330         if (['s','p'].includes(piece) && !['s','p'].includes(move.appear[0].p))
 331         {
 332             // Promotion
 333             notation += "=" + move.appear[0].p.toUpperCase();
 334         }
 335         return notation;
 336     }
 337 }