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