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