client/src/variants/Alice.js

   1 import { ChessRules } from "@/base_rules";
   2 // NOTE: alternative implementation, probably cleaner = use only 1 board
   3 export const VariantRules = class AliceRules extends ChessRules
   4 {
   5     static get ALICE_PIECES()
   6     {
   7         return {
   8             's': 'p',
   9             't': 'q',
  10             'u': 'r',
  11             'c': 'b',
  12             'o': 'n',
  13             'l': 'k',
  14         };
  15     }
  16     static get ALICE_CODES()
  17     {
  18         return {
  19             'p': 's',
  20             'q': 't',
  21             'r': 'u',
  22             'b': 'c',
  23             'n': 'o',
  24             'k': 'l',
  25         };
  26     }
  27
  28     static getPpath(b)
  29     {
  30         return (Object.keys(this.ALICE_PIECES).includes(b[1]) ? "Alice/" : "") + b;
  31     }
  32
  33     static get PIECES()
  34     {
  35         return ChessRules.PIECES.concat(Object.keys(V.ALICE_PIECES));
  36     }
  37
  38     setOtherVariables(fen)
  39     {
  40         super.setOtherVariables(fen);
  41         const rows = V.ParseFen(fen).position.split("/");
  42         if (this.kingPos["w"][0] < 0 || this.kingPos["b"][0] < 0)
  43         {
  44             // INIT_COL_XXX won't be required if Alice kings are found (means 'king moved')
  45             for (let i=0; i<rows.length; i++)
  46             {
  47                 let k = 0; //column index on board
  48                 for (let j=0; j<rows[i].length; j++)
  49                 {
  50                     switch (rows[i].charAt(j))
  51                     {
  52                         case 'l':
  53                             this.kingPos['b'] = [i,k];
  54                             break;
  55                         case 'L':
  56                             this.kingPos['w'] = [i,k];
  57                             break;
  58                         default:
  59                             const num = parseInt(rows[i].charAt(j));
  60                             if (!isNaN(num))
  61                                 k += (num-1);
  62                     }
  63                     k++;
  64                 }
  65             }
  66         }
  67     }
  68
  69     // Return the (standard) color+piece notation at a square for a board
  70     getSquareOccupation(i, j, mirrorSide)
  71     {
  72         const piece = this.getPiece(i,j);
  73         if (mirrorSide==1 && Object.keys(V.ALICE_CODES).includes(piece))
  74             return this.board[i][j];
  75         else if (mirrorSide==2 && Object.keys(V.ALICE_PIECES).includes(piece))
  76             return this.getColor(i,j) + V.ALICE_PIECES[piece];
  77         return "";
  78     }
  79
  80     // Build board of the given (mirror)side
  81     getSideBoard(mirrorSide)
  82     {
  83         // Build corresponding board from complete board
  84         let sideBoard = doubleArray(V.size.x, V.size.y, "");
  85         for (let i=0; i<V.size.x; i++)
  86         {
  87             for (let j=0; j<V.size.y; j++)
  88                 sideBoard[i][j] = this.getSquareOccupation(i, j, mirrorSide);
  89         }
  90         return sideBoard;
  91     }
  92
  93     // NOTE: castle & enPassant https://www.chessvariants.com/other.dir/alice.html
  94     getPotentialMovesFrom([x,y], sideBoard)
  95     {
  96         const pieces = Object.keys(V.ALICE_CODES);
  97         const codes = Object.keys(V.ALICE_PIECES);
  98         const mirrorSide = (pieces.includes(this.getPiece(x,y)) ? 1 : 2);
  99         const color = this.getColor(x,y);
 100
 101         // Search valid moves on sideBoard
 102         let saveBoard = this.board;
 103         this.board = sideBoard || this.getSideBoard(mirrorSide);
 104         let moves = super.getPotentialMovesFrom([x,y])
 105             .filter(m => {
 106                 // Filter out king moves which result in under-check position on
 107                 // current board (before mirror traversing)
 108                 let aprioriValid = true;
 109                 if (m.appear[0].p == V.KING)
 110                 {
 111                     this.play(m);
 112                     if (this.underCheck(color))
 113                         aprioriValid = false;
 114                     this.undo(m);
 115                 }
 116                 return aprioriValid;
 117             });
 118         this.board = saveBoard;
 119
 120         // Finally filter impossible moves
 121         let res = moves.filter(m => {
 122             if (m.appear.length == 2) //castle
 123             {
 124                 // appear[i] must be an empty square on the other board
 125                 for (let psq of m.appear)
 126                 {
 127                     if (this.getSquareOccupation(psq.x,psq.y,3-mirrorSide) != V.EMPTY)
 128                         return false;
 129                 }
 130             }
 131             else if (this.board[m.end.x][m.end.y] != V.EMPTY)
 132             {
 133                 // Attempt to capture
 134                 const piece = this.getPiece(m.end.x,m.end.y);
 135                 if ((mirrorSide==1 && codes.includes(piece))
 136                     || (mirrorSide==2 && pieces.includes(piece)))
 137                 {
 138                     return false;
 139                 }
 140             }
 141             // If the move is computed on board1, m.appear change for Alice pieces.
 142             if (mirrorSide==1)
 143             {
 144                 m.appear.forEach(psq => { //forEach: castling taken into account
 145                     psq.p = V.ALICE_CODES[psq.p]; //goto board2
 146                 });
 147             }
 148             else //move on board2: mark vanishing pieces as Alice
 149             {
 150                 m.vanish.forEach(psq => {
 151                     psq.p = V.ALICE_CODES[psq.p];
 152                 });
 153             }
 154             // Fix en-passant captures
 155             if (m.vanish[0].p == V.PAWN && m.vanish.length == 2
 156                 && this.board[m.end.x][m.end.y] == V.EMPTY)
 157             {
 158                 m.vanish[1].c = V.GetOppCol(this.getColor(x,y));
 159                 // In the special case of en-passant, if
 160                 //  - board1 takes board2 : vanish[1] --> Alice
 161                 //  - board2 takes board1 : vanish[1] --> normal
 162                 let van = m.vanish[1];
 163                 if (mirrorSide==1 && codes.includes(this.getPiece(van.x,van.y)))
 164                     van.p = V.ALICE_CODES[van.p];
 165                 else if (mirrorSide==2 && pieces.includes(this.getPiece(van.x,van.y)))
 166                     van.p = V.ALICE_PIECES[van.p];
 167             }
 168             return true;
 169         });
 170         return res;
 171     }
 172
 173     filterValid(moves)
 174     {
 175         if (moves.length == 0)
 176             return [];
 177         let sideBoard = [this.getSideBoard(1), this.getSideBoard(2)];
 178         const color = this.turn;
 179         return moves.filter(m => {
 180             this.playSide(m, sideBoard); //no need to track flags
 181             const res = !this.underCheck(color, sideBoard);
 182             this.undoSide(m, sideBoard);
 183             return res;
 184         });
 185     }
 186
 187     getAllValidMoves()
 188     {
 189         const color = this.turn;
 190         const oppCol = V.GetOppCol(color);
 191         var potentialMoves = [];
 192         let sideBoard = [this.getSideBoard(1), this.getSideBoard(2)];
 193         for (var i=0; i<V.size.x; i++)
 194         {
 195             for (var j=0; j<V.size.y; j++)
 196             {
 197                 if (this.board[i][j] != V.EMPTY && this.getColor(i,j) == color)
 198                 {
 199                     const mirrorSide =
 200                         Object.keys(V.ALICE_CODES).includes(this.getPiece(i,j))
 201                             ? 1
 202                             : 2;
 203                     Array.prototype.push.apply(potentialMoves,
 204                         this.getPotentialMovesFrom([i,j], sideBoard[mirrorSide-1]));
 205                 }
 206             }
 207         }
 208         return this.filterValid(potentialMoves, sideBoard);
 209     }
 210
 211     // Play on sideboards [TODO: only one sideBoard required]
 212     playSide(move, sideBoard)
 213     {
 214         const pieces = Object.keys(V.ALICE_CODES);
 215         move.vanish.forEach(psq => {
 216             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 217             sideBoard[mirrorSide-1][psq.x][psq.y] = V.EMPTY;
 218         });
 219         move.appear.forEach(psq => {
 220             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 221             const piece = (mirrorSide == 1 ? psq.p : V.ALICE_PIECES[psq.p]);
 222             sideBoard[mirrorSide-1][psq.x][psq.y] = psq.c + piece;
 223             if (piece == V.KING)
 224                 this.kingPos[psq.c] = [psq.x,psq.y];
 225         });
 226     }
 227
 228     // Undo on sideboards
 229     undoSide(move, sideBoard)
 230     {
 231         const pieces = Object.keys(V.ALICE_CODES);
 232         move.appear.forEach(psq => {
 233             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 234             sideBoard[mirrorSide-1][psq.x][psq.y] = V.EMPTY;
 235         });
 236         move.vanish.forEach(psq => {
 237             const mirrorSide = (pieces.includes(psq.p) ? 1 : 2);
 238             const piece = (mirrorSide == 1 ? psq.p : V.ALICE_PIECES[psq.p]);
 239             sideBoard[mirrorSide-1][psq.x][psq.y] = psq.c + piece;
 240             if (piece == V.KING)
 241                 this.kingPos[psq.c] = [psq.x,psq.y];
 242         });
 243     }
 244
 245     underCheck(color, sideBoard) //sideBoard arg always provided
 246     {
 247         const kp = this.kingPos[color];
 248         const mirrorSide = (sideBoard[0][kp[0]][kp[1]] != V.EMPTY ? 1 : 2);
 249         let saveBoard = this.board;
 250         this.board = sideBoard[mirrorSide-1];
 251         let res = this.isAttacked(kp, [V.GetOppCol(color)]);
 252         this.board = saveBoard;
 253         return res;
 254     }
 255
 256     getCheckSquares(color)
 257     {
 258         const pieces = Object.keys(V.ALICE_CODES);
 259         const kp = this.kingPos[color];
 260         const mirrorSide = (pieces.includes(this.getPiece(kp[0],kp[1])) ? 1 : 2);
 261         let sideBoard = this.getSideBoard(mirrorSide);
 262         let saveBoard = this.board;
 263         this.board = sideBoard;
 264         let res = this.isAttacked(this.kingPos[color], [V.GetOppCol(color)])
 265             ? [ JSON.parse(JSON.stringify(this.kingPos[color])) ]
 266             : [ ];
 267         this.board = saveBoard;
 268         return res;
 269     }
 270
 271     updateVariables(move)
 272     {
 273         super.updateVariables(move); //standard king
 274         const piece = move.vanish[0].p;
 275         const c = move.vanish[0].c;
 276         // "l" = Alice king
 277         if (piece == "l")
 278         {
 279             this.kingPos[c][0] = move.appear[0].x;
 280             this.kingPos[c][1] = move.appear[0].y;
 281             this.castleFlags[c] = [false,false];
 282         }
 283     }
 284
 285     unupdateVariables(move)
 286     {
 287         super.unupdateVariables(move);
 288         const c = move.vanish[0].c;
 289         if (move.vanish[0].p == "l")
 290             this.kingPos[c] = [move.start.x, move.start.y];
 291     }
 292
 293     checkGameEnd()
 294     {
 295         const pieces = Object.keys(V.ALICE_CODES);
 296         const color = this.turn;
 297         const kp = this.kingPos[color];
 298         const mirrorSide = (pieces.includes(this.getPiece(kp[0],kp[1])) ? 1 : 2);
 299         let sideBoard = this.getSideBoard(mirrorSide);
 300         let saveBoard = this.board;
 301         this.board = sideBoard;
 302         let res = "*";
 303         if (!this.isAttacked(this.kingPos[color], [V.GetOppCol(color)]))
 304             res = "1/2";
 305         else
 306             res = (color == "w" ? "0-1" : "1-0");
 307         this.board = saveBoard;
 308         return res;
 309     }
 310
 311     static get VALUES()
 312     {
 313         return Object.assign(
 314             ChessRules.VALUES,
 315             {
 316                 's': 1,
 317                 'u': 5,
 318                 'o': 3,
 319                 'c': 3,
 320                 't': 9,
 321                 'l': 1000,
 322             }
 323         );
 324     }
 325
 326     getNotation(move)
 327     {
 328         if (move.appear.length == 2 && move.appear[0].p == V.KING)
 329         {
 330             if (move.end.y < move.start.y)
 331                 return "0-0-0";
 332             else
 333                 return "0-0";
 334         }
 335
 336         const finalSquare = V.CoordsToSquare(move.end);
 337         const piece = this.getPiece(move.start.x, move.start.y);
 338
 339         const captureMark = (move.vanish.length > move.appear.length ? "x" : "");
 340         let pawnMark = "";
 341         if (["p","s"].includes(piece) && captureMark.length == 1)
 342             pawnMark = V.CoordToColumn(move.start.y); //start column
 343
 344         // Piece or pawn movement
 345         let notation = piece.toUpperCase() + pawnMark + captureMark + finalSquare;
 346         if (['s','p'].includes(piece) && !['s','p'].includes(move.appear[0].p))
 347         {
 348             // Promotion
 349             notation += "=" + move.appear[0].p.toUpperCase();
 350         }
 351         return notation;
 352     }
 353 }