variants/Checkered/class.js

   1 import ChessRules from "/base_rules.js";
   2 import PiPo from "/utils/PiPo.js";
   3 import Move from "/utils/Move.js";
   4
   5 export default class CheckeredRules extends ChessRules {
   6
   7   static get Options() {
   8     return {
   9       select: C.Options.select,
  10       input: [
  11         {
  12           label: "Allow switching",
  13           variable: "withswitch",
  14           type: "checkbox",
  15           defaut: false
  16         }
  17       ],
  18       styles: [
  19         "balance",
  20         "capture",
  21         "cylinder",
  22         "doublemove",
  23         "madrasi",
  24         "progressive",
  25         "recycle",
  26         "teleport"
  27       ]
  28     };
  29   }
  30
  31   static GetColorClass(c) {
  32     if (c == 'c')
  33       return "checkered";
  34     return C.GetColorClass(c);
  35   }
  36
  37   static board2fen(b) {
  38     const checkered_codes = {
  39       p: "s",
  40       q: "t",
  41       r: "u",
  42       b: "c",
  43       n: "o"
  44     };
  45     if (b[0] == "c")
  46       return checkered_codes[b[1]];
  47     return super.board2fen(b);
  48   }
  49
  50   static fen2board(f) {
  51     // Tolerate upper-case versions of checkered pieces (why not?)
  52     const checkered_pieces = {
  53       s: "p",
  54       S: "p",
  55       t: "q",
  56       T: "q",
  57       u: "r",
  58       U: "r",
  59       c: "b",
  60       C: "b",
  61       o: "n",
  62       O: "n"
  63     };
  64     if (Object.keys(checkered_pieces).includes(f))
  65       return "c" + checkered_pieces[f];
  66     return super.fen2board(f);
  67   }
  68
  69   genRandInitBaseFen() {
  70     let res = super.genRandInitBaseFen();
  71     res.o.flags += "1".repeat(16); //pawns flags
  72     return res;
  73   }
  74
  75   getPartFen(o) {
  76     return Object.assign(
  77       {
  78         "cmove": o.init ? "-" : this.getCmoveFen(),
  79         "stage": o.init ? "1" : this.getStageFen()
  80       },
  81       super.getPartFen(o)
  82     );
  83   }
  84
  85   getCmoveFen() {
  86     if (!this.cmove)
  87       return "-";
  88     return (
  89       C.CoordsToSquare(this.cmove.start) + C.CoordsToSquare(this.cmove.end)
  90     );
  91   }
  92
  93   getStageFen() {
  94     return (this.stage + this.sideCheckered);
  95   }
  96
  97   getFlagsFen() {
  98     let fen = super.getFlagsFen();
  99     // Add pawns flags
 100     for (let c of ["w", "b"]) {
 101       for (let i = 0; i < 8; i++)
 102         fen += (this.pawnFlags[c][i] ? "1" : "0");
 103     }
 104     return fen;
 105   }
 106
 107   getPawnShift(color) {
 108     return super.getPawnShift(color == 'c' ? this.turn : color);
 109   }
 110
 111   getOppCols(color) {
 112     if (this.stage == 1)
 113       return super.getOppCols(color).concat(['c']);
 114     // Stage 2: depends if color is w+b or checkered
 115     if (color == this.sideCheckered)
 116       return ['w', 'b'];
 117     return ['c'];
 118   }
 119
 120   pieces(color, x, y) {
 121     let baseRes = super.pieces(color, x, y);
 122     if (
 123       this.getPiece(x, y) == 'p' &&
 124       this.stage == 2 &&
 125       this.getColor(x, y) == 'c'
 126     ) {
 127       // Checkered pawns on stage 2 are bidirectional
 128       const initRank = ((color == 'w' && x >= 6) || (color == 'b' && x <= 1));
 129       baseRes['p'] = {
 130         "class": "pawn",
 131         moves: [
 132           {
 133             steps: [[1, 0], [-1, 0]],
 134             range: (initRank ? 2 : 1)
 135           }
 136         ],
 137         attack: [
 138           {
 139             steps: [[1, 1], [1, -1], [-1, 1], [-1, -1]],
 140             range: 1
 141           }
 142         ]
 143       };
 144     }
 145     const checkered = {
 146       's': {"class": "checkered-pawn", moveas: 'p'},
 147       'u': {"class": "checkered-rook", moveas: 'r'},
 148       'o': {"class": "checkered-knight", moveas: 'n'},
 149       'c': {"class": "checkered-bishop", moveas: 'b'},
 150       't': {"class": "checkered-queen", moveas: 'q'}
 151     };
 152     return Object.assign(baseRes, checkered);
 153   }
 154
 155   setOtherVariables(fenParsed) {
 156     super.setOtherVariables(fenParsed);
 157     // Non-capturing last checkered move (if any)
 158     const cmove = fenParsed.cmove;
 159     if (cmove == "-") this.cmove = null;
 160     else {
 161       this.cmove = {
 162         start: C.SquareToCoords(cmove.substr(0, 2)),
 163         end: C.SquareToCoords(cmove.substr(2))
 164       };
 165     }
 166     // Stage 1: as Checkered2. Stage 2: checkered pieces are autonomous
 167     const stageInfo = fenParsed.stage;
 168     this.stage = parseInt(stageInfo[0], 10);
 169     this.sideCheckered = (this.stage == 2 ? stageInfo[1] : "");
 170   }
 171
 172   setFlags(fenflags) {
 173     super.setFlags(fenflags); //castleFlags
 174     this.pawnFlags = {
 175       w: [...Array(8)], //pawns can move 2 squares?
 176       b: [...Array(8)]
 177     };
 178     const flags = fenflags.substr(4); //skip first 4 letters, for castle
 179     for (let c of ["w", "b"]) {
 180       for (let i = 0; i < 8; i++)
 181         this.pawnFlags[c][i] = flags.charAt((c == "w" ? 0 : 8) + i) == "1";
 182     }
 183   }
 184
 185   getEpSquare(moveOrSquare) {
 186     // At stage 2, all pawns can be captured en-passant
 187     if (
 188       this.stage == 2 ||
 189       typeof moveOrSquare !== "object" ||
 190       (moveOrSquare.appear.length > 0 && moveOrSquare.appear[0].c != 'c')
 191     )
 192       return super.getEpSquare(moveOrSquare);
 193     // Checkered or switch move: no en-passant
 194     return undefined;
 195   }
 196
 197   getCmove(move) {
 198     // No checkered move to undo at stage 2:
 199     if (this.stage == 1 && move.vanish.length == 1 && move.appear[0].c == "c")
 200       return {start: move.start, end: move.end};
 201     return null;
 202   }
 203
 204   canTake([x1, y1], [x2, y2]) {
 205     const color1 = this.getColor(x1, y1);
 206     const color2 = this.getColor(x2, y2);
 207     if (this.stage == 2) {
 208       // Black & White <-- takes --> Checkered
 209       const color1 = this.getColor(x1, y1);
 210       const color2 = this.getColor(x2, y2);
 211       return color1 != color2 && [color1, color2].includes('c');
 212     }
 213     return (
 214       color1 != color2 &&
 215       color2 != "c" && //checkered aren't captured
 216       (color1 != "c" || color2 != this.turn)
 217     );
 218   }
 219
 220   postProcessPotentialMoves(moves) {
 221     if (this.stage == 2 || moves.length == 0)
 222       return moves;
 223     const color = this.turn;
 224     // Apply "checkerization" of standard moves
 225     const lastRank = (color == "w" ? 0 : 7);
 226     const [x, y] = [moves[0].start.x, moves[0].start.y];
 227     const piece = this.getPiece(x, y);
 228     // King is treated differently: it never turn checkered
 229     if (piece == 'k' && this.stage == 1) {
 230       // If at least one checkered piece, allow switching:
 231       if (
 232         this.options["withswitch"] &&
 233         this.board.some(b => b.some(cell => cell[0] == 'c'))
 234       ) {
 235         const oppKingPos = this.searchKingPos(C.GetOppTurn(this.turn))[0];
 236         moves.push(
 237           new Move({
 238             start: { x: x, y: y },
 239             end: {x: oppKingPos[0], y: oppKingPos[1]},
 240             appear: [],
 241             vanish: []
 242           })
 243         );
 244       }
 245       return moves;
 246     }
 247     if (piece == 'p') {
 248       // Filter out forbidden pawn moves
 249       moves = moves.filter(m => {
 250         if (m.vanish.length > 0 && m.vanish[0].p == 'p') {
 251           if (
 252             Math.abs(m.end.x - m.start.x) == 2 &&
 253             !this.pawnFlags[this.turn][m.start.y]
 254           ) {
 255             return false; //forbidden 2-squares jumps
 256           }
 257           if (
 258             this.board[m.end.x][m.end.y] == "" &&
 259             m.vanish.length == 2 &&
 260             this.getColor(m.start.x, m.start.y) == "c"
 261           ) {
 262             return false; //checkered pawns cannot take en-passant
 263           }
 264         }
 265         return true;
 266       });
 267     }
 268     let extraMoves = [];
 269     moves.forEach(m => {
 270       if (m.vanish.length == 2 && m.appear.length == 1) {
 271         // A capture occured
 272         m.appear[0].c = "c";
 273         if (
 274           m.appear[0].p != m.vanish[1].p &&
 275           // No choice if promotion:
 276           (m.vanish[0].p != 'p' || m.end.x != lastRank)
 277         ) {
 278           // Add transformation into captured piece
 279           let m2 = JSON.parse(JSON.stringify(m));
 280           m2.appear[0].p = m.vanish[1].p;
 281           extraMoves.push(m2);
 282         }
 283       }
 284     });
 285     return moves.concat(extraMoves);
 286   }
 287
 288   canIplay(x, y) {
 289     if (this.stage == 2) {
 290       const color = this.getColor(x, y);
 291       return (
 292         this.turn == this.sideCheckered
 293           ? color == 'c'
 294           : ['w', 'b'].includes(color)
 295       );
 296     }
 297     return (
 298       this.playerColor == this.turn &&
 299       [this.turn, "c"].includes(this.getColor(x, y))
 300     );
 301   }
 302
 303   // Does m2 un-do m1 ? (to disallow undoing checkered moves)
 304   oppositeMoves(m1, m2) {
 305     return (
 306       !!m1 &&
 307       m2.appear.length == 1 &&
 308       m2.vanish.length == 1 &&
 309       m2.appear[0].c == "c" &&
 310       m1.start.x == m2.end.x &&
 311       m1.end.x == m2.start.x &&
 312       m1.start.y == m2.end.y &&
 313       m1.end.y == m2.start.y
 314     );
 315   }
 316
 317   filterValid(moves) {
 318     const color = this.turn;
 319     if (this.stage == 2 && this.sideCheckered == color)
 320       // Checkered cannot be under check (no king)
 321       return moves;
 322     let kingPos = super.searchKingPos(color);
 323     if (this.stage == 2)
 324       // Must consider both kings (attacked by checkered side)
 325       kingPos = [kingPos, super.searchKingPos(C.GetOppTurn(this.turn))];
 326     const oppCols = this.getOppCols(color);
 327     return moves.filter(m => {
 328       this.playOnBoard(m);
 329       let res = true;
 330       if (this.stage == 1)
 331         res = !this.oppositeMoves(this.cmove, m);
 332       if (res && m.appear.length > 0)
 333         res = !this.underCheck(kingPos, oppCols);
 334       this.undoOnBoard(m);
 335       return res;
 336     });
 337   }
 338
 339   atLeastOneMove(color) {
 340     const myCols = [color, 'c'];
 341     for (let i = 0; i < this.size.x; i++) {
 342       for (let j = 0; j < this.size.y; j++) {
 343         const colIJ = this.getColor(i, j);
 344         if (
 345           this.board[i][j] != "" &&
 346           (
 347             (this.stage == 1 && myCols.includes(colIJ)) ||
 348             (this.stage == 2 &&
 349               (
 350                 (this.sideCheckered == color && colIJ == 'c') ||
 351                 (this.sideCheckered != color && ['w', 'b'].includes(colIJ))
 352               )
 353             )
 354           )
 355         ) {
 356           const moves = this.getPotentialMovesFrom([i, j]);
 357           if (moves.some(m => this.filterValid([m]).length >= 1))
 358             return true;
 359         }
 360       }
 361     }
 362     return false;
 363   }
 364
 365   underCheck(square_s, oppCols) {
 366     if (this.stage == 2 && oppCol != this.sideCheckered)
 367       return false; //checkered pieces is me, I'm not under check
 368     return square_s.some(sq => super.underAttack(sq, oppCols));
 369   }
 370
 371   prePlay(move) {
 372     if (move.appear.length > 0 && move.vanish.length > 0) {
 373       super.prePlay(move);
 374       if (
 375         [1, 6].includes(move.start.x) &&
 376         move.vanish[0].p == 'p' &&
 377         Math.abs(move.end.x - move.start.x) == 2
 378       ) {
 379         // This move turns off a 2-squares pawn flag
 380         this.pawnFlags[move.start.x == 6 ? "w" : "b"][move.start.y] = false;
 381       }
 382     }
 383   }
 384
 385   postPlay(move) {
 386     if (move.appear.length == 0 && move.vanish.length == 0) {
 387       this.stage = 2;
 388       this.sideCheckered = this.turn;
 389     }
 390     else
 391       super.postPlay(move);
 392     this.cmove = this.getCmove(move);
 393   }
 394
 395   tryChangeTurn(move) {
 396     if (move.appear.length > 0 && move.vanish.length > 0)
 397       super.tryChangeTurn(move);
 398   }
 399
 400   getCurrentScore() {
 401     const color = this.turn;
 402     if (this.stage == 1) {
 403       if (this.atLeastOneMove(color))
 404         return "*";
 405       // Artifically change turn, for checkered pawns
 406       const oppTurn = C.GetOppTurn(color);
 407       this.turn = oppTurn;
 408       const kingPos = super.searchKingPos(color)[0];
 409       let res = "1/2";
 410       if (super.underAttack(kingPos, [oppTurn, 'c']))
 411         res = (color == "w" ? "0-1" : "1-0");
 412       this.turn = color;
 413       return res;
 414     }
 415     // Stage == 2:
 416     if (this.sideCheckered == color) {
 417       // Check if remaining checkered pieces: if none, I lost
 418       if (this.board.some(b => b.some(cell => cell[0] == 'c'))) {
 419         if (!this.atLeastOneMove(color))
 420           return "1/2";
 421         return "*";
 422       }
 423       return (color == 'w' ? "0-1" : "1-0");
 424     }
 425     if (this.atLeastOneMove(color))
 426       return "*";
 427     let res = super.underAttack(super.searchKingPos(color)[0], ['c']);
 428     if (!res)
 429       res = super.underAttack(super.searchKingPos(oppCol)[0], ['c']);
 430     if (res)
 431       return (color == 'w' ? "0-1" : "1-0");
 432     return "1/2";
 433   }
 434
 435 };