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         const color = this.getColor(x,y);
  99
 100         // Search valid moves on sideBoard
 101         let saveBoard = this.board;
 102         this.board = sideBoard || this.getSideBoard(mirrorSide);
 103         let moves = super.getPotentialMovesFrom([x,y])
 104             .filter(m => {
 105                 // Filter out king moves which result in under-check position on
 106                 // current board (before mirror traversing)
 107                 let aprioriValid = true;
 108                 if (m.appear[0].p == V.KING)
 109                 {
 110                     this.play(m);
 111                     if (this.underCheck(color))
 112                         aprioriValid = false;
 113                     this.undo(m);
 114                 }
 115                 return aprioriValid;
 116             });
 117         this.board = saveBoard;
 118
 119         // Finally filter impossible moves
 120         let res = moves.filter(m => {
 121             if (m.appear.length == 2) //castle
 122             {
 123                 // appear[i] must be an empty square on the other board
 124                 for (let psq of m.appear)
 125                 {
 126                     if (this.getSquareOccupation(psq.x,psq.y,3-mirrorSide) != V.EMPTY)
 127                         return false;
 128                 }
 129             }
 130             else if (this.board[m.end.x][m.end.y] != V.EMPTY)
 131             {
 132                 // Attempt to capture
 133                 const piece = this.getPiece(m.end.x,m.end.y);
 134                 if ((mirrorSide==1 && codes.includes(piece))
 135                     || (mirrorSide==2 && pieces.includes(piece)))
 136                 {
 137                     return false;
 138                 }
 139             }
 140             // If the move is computed on board1, m.appear change for Alice pieces.
 141             if (mirrorSide==1)
 142             {
 143                 m.appear.forEach(psq => { //forEach: castling taken into account
 144                     psq.p = V.ALICE_CODES[psq.p]; //goto board2
 145                 });
 146             }
 147             else //move on board2: mark vanishing pieces as Alice
 148             {
 149                 m.vanish.forEach(psq => {
 150                     psq.p = V.ALICE_CODES[psq.p];
 151                 });
 152             }
 153             // Fix en-passant captures
 154             if (m.vanish[0].p == V.PAWN && m.vanish.length == 2
 155                 && this.board[m.end.x][m.end.y] == V.EMPTY)
 156             {
 157                 m.vanish[1].c = V.GetOppCol(this.getColor(x,y));
 158                 // In the special case of en-passant, if
 159                 //  - board1 takes board2 : vanish[1] --> Alice
 160                 //  - board2 takes board1 : vanish[1] --> normal
 161                 let van = m.vanish[1];
 162                 if (mirrorSide==1 && codes.includes(this.getPiece(van.x,van.y)))
 163                     van.p = V.ALICE_CODES[van.p];
 164                 else if (mirrorSide==2 && pieces.includes(this.getPiece(van.x,van.y)))
 165                     van.p = V.ALICE_PIECES[van.p];
 166             }
 167             return true;
 168         });
 169         return res;
 170     }
 171
 172     filterValid(moves)
 173     {
 174         if (moves.length == 0)
 175             return [];
 176         let sideBoard = [this.getSideBoard(1), this.getSideBoard(2)];
 177         const color = this.turn;
 178         return moves.filter(m => {
 179             this.playSide(m, sideBoard); //no need to track flags
 180             const res = !this.underCheck(color, sideBoard);
 181             this.undoSide(m, sideBoard);
 182             return res;
 183         });
 184     }
 185
 186     getAllValidMoves()
 187     {
 188         const color = this.turn;
 189         const oppCol = V.GetOppCol(color);
 190         var potentialMoves = [];
 191         let sideBoard = [this.getSideBoard(1), this.getSideBoard(2)];
 192         for (var i=0; i<V.size.x; i++)
 193         {
 194             for (var j=0; j<V.size.y; j++)
 195             {
 196                 if (this.board[i][j] != V.EMPTY && this.getColor(i,j) == color)
 197                 {
 198                     const mirrorSide =
 199                         Object.keys(V.ALICE_CODES).includes(this.getPiece(i,j))
 200                             ? 1
 201                             : 2;
 202                     Array.prototype.push.apply(potentialMoves,
 203                         this.getPotentialMovesFrom([i,j], sideBoard[mirrorSide-1]));
 204                 }
 205             }
 206         }
 207         return this.filterValid(potentialMoves, sideBoard);
 208     }
 209
 210     // Play on sideboards [TODO: only one sideBoard required]
 211     playSide(move, sideBoard)
 212     {
 213         const pieces = Object.keys(V.ALICE_CODES);
 214         move.vanish.forEach(psq => {
 215             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 216             sideBoard[mirrorSide-1][psq.x][psq.y] = V.EMPTY;
 217         });
 218         move.appear.forEach(psq => {
 219             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 220             const piece = (mirrorSide == 1 ? psq.p : V.ALICE_PIECES[psq.p]);
 221             sideBoard[mirrorSide-1][psq.x][psq.y] = psq.c + piece;
 222             if (piece == V.KING)
 223                 this.kingPos[psq.c] = [psq.x,psq.y];
 224         });
 225     }
 226
 227     // Undo on sideboards
 228     undoSide(move, sideBoard)
 229     {
 230         const pieces = Object.keys(V.ALICE_CODES);
 231         move.appear.forEach(psq => {
 232             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 233             sideBoard[mirrorSide-1][psq.x][psq.y] = V.EMPTY;
 234         });
 235         move.vanish.forEach(psq => {
 236             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 237             const piece = (mirrorSide == 1 ? psq.p : V.ALICE_PIECES[psq.p]);
 238             sideBoard[mirrorSide-1][psq.x][psq.y] = psq.c + piece;
 239             if (piece == V.KING)
 240                 this.kingPos[psq.c] = [psq.x,psq.y];
 241         });
 242     }
 243
 244     underCheck(color, sideBoard) //sideBoard arg always provided
 245     {
 246         const kp = this.kingPos[color];
 247         const mirrorSide = (sideBoard[0][kp[0]][kp[1]] != V.EMPTY ? 1 : 2);
 248         let saveBoard = this.board;
 249         this.board = sideBoard[mirrorSide-1];
 250         let res = this.isAttacked(kp, [V.GetOppCol(color)]);
 251         this.board = saveBoard;
 252         return res;
 253     }
 254
 255     getCheckSquares(color)
 256     {
 257         const pieces = Object.keys(V.ALICE_CODES);
 258         const kp = this.kingPos[color];
 259         const mirrorSide = (pieces.includes(this.getPiece(kp[0],kp[1])) ? 1 : 2);
 260         let sideBoard = this.getSideBoard(mirrorSide);
 261         let saveBoard = this.board;
 262         this.board = sideBoard;
 263         let res = this.isAttacked(this.kingPos[color], [V.GetOppCol(color)])
 264             ? [ JSON.parse(JSON.stringify(this.kingPos[color])) ]
 265             : [ ];
 266         this.board = saveBoard;
 267         return res;
 268     }
 269
 270     updateVariables(move)
 271     {
 272         super.updateVariables(move); //standard king
 273         const piece = move.vanish[0].p;
 274         const c = move.vanish[0].c;
 275         // "l" = Alice king
 276         if (piece == "l")
 277         {
 278             this.kingPos[c][0] = move.appear[0].x;
 279             this.kingPos[c][1] = move.appear[0].y;
 280             this.castleFlags[c] = [false,false];
 281         }
 282     }
 283
 284     unupdateVariables(move)
 285     {
 286         super.unupdateVariables(move);
 287         const c = move.vanish[0].c;
 288         if (move.vanish[0].p == "l")
 289             this.kingPos[c] = [move.start.x, move.start.y];
 290     }
 291
 292     checkGameEnd()
 293     {
 294         const pieces = Object.keys(V.ALICE_CODES);
 295         const color = this.turn;
 296         const kp = this.kingPos[color];
 297         const mirrorSide = (pieces.includes(this.getPiece(kp[0],kp[1])) ? 1 : 2);
 298         let sideBoard = this.getSideBoard(mirrorSide);
 299         let saveBoard = this.board;
 300         this.board = sideBoard;
 301         let res = "*";
 302         if (!this.isAttacked(this.kingPos[color], [V.GetOppCol(color)]))
 303             res = "1/2";
 304         else
 305             res = (color == "w" ? "0-1" : "1-0");
 306         this.board = saveBoard;
 307         return res;
 308     }
 309
 310     static get VALUES()
 311     {
 312         return Object.assign(
 313             ChessRules.VALUES,
 314             {
 315                 's': 1,
 316                 'u': 5,
 317                 'o': 3,
 318                 'c': 3,
 319                 't': 9,
 320                 'l': 1000,
 321             }
 322         );
 323     }
 324
 325     getNotation(move)
 326     {
 327         if (move.appear.length == 2 && move.appear[0].p == V.KING)
 328         {
 329             if (move.end.y < move.start.y)
 330                 return "0-0-0";
 331             else
 332                 return "0-0";
 333         }
 334
 335         const finalSquare = V.CoordsToSquare(move.end);
 336         const piece = this.getPiece(move.start.x, move.start.y);
 337
 338         const captureMark = (move.vanish.length > move.appear.length ? "x" : "");
 339         let pawnMark = "";
 340         if (["p","s"].includes(piece) && captureMark.length == 1)
 341             pawnMark = V.CoordToColumn(move.start.y); //start column
 342
 343         // Piece or pawn movement
 344         let notation = piece.toUpperCase() + pawnMark + captureMark + finalSquare;
 345         if (['s','p'].includes(piece) && !['s','p'].includes(move.appear[0].p))
 346         {
 347             // Promotion
 348             notation += "=" + move.appear[0].p.toUpperCase();
 349         }
 350         return notation;
 351     }
 352 }