client/src/variants/Ball.js

   1 import { ChessRules, Move, PiPo } from "@/base_rules";
   2 import { WildebeestRules } from "@/variants/Wildebeest";
   3 import { ArrayFun } from "@/utils/array";
   4 import { shuffle } from "@/utils/alea";
   5
   6 export class BallRules extends ChessRules {
   7   static get PawnSpecs() {
   8     return Object.assign(
   9       {},
  10       ChessRules.PawnSpecs,
  11       { promotions: ChessRules.PawnSpecs.promotions.concat([V.WILDEBEEST]) }
  12     );
  13   }
  14
  15   static get HasFlags() {
  16     return false;
  17   }
  18   static get HasCastle() {
  19     return false;
  20   }
  21
  22   static get WILDEBEEST() {
  23     return 'w';
  24   }
  25
  26   static get BALL() {
  27     // 'b' is already taken:
  28     return "aa";
  29   }
  30
  31   // Special code for "something to fill space" (around goals)
  32   // --> If goal is outside the board (current prototype: it's inside)
  33 //  static get FILL() {
  34 //    return "ff";
  35 //  }
  36
  37   static get HAS_BALL_CODE() {
  38     return {
  39       'p': 's',
  40       'r': 'u',
  41       'n': 'o',
  42       'b': 'c',
  43       'q': 't',
  44       'k': 'l',
  45       'w': 'y'
  46     };
  47   }
  48
  49   static get HAS_BALL_DECODE() {
  50     return {
  51       's': 'p',
  52       'u': 'r',
  53       'o': 'n',
  54       'c': 'b',
  55       't': 'q',
  56       'l': 'k',
  57       'y': 'w'
  58     };
  59   }
  60
  61   static get PIECES() {
  62     return ChessRules.PIECES
  63       .concat([V.WILDEBEEST])
  64       .concat(Object.keys(V.HAS_BALL_DECODE))
  65       .concat(['a']);
  66   }
  67
  68   static board2fen(b) {
  69     if (b == V.BALL) return 'a';
  70     return ChessRules.board2fen(b);
  71   }
  72
  73   static fen2board(f) {
  74     if (f == 'a') return V.BALL;
  75     return ChessRules.fen2board(f);
  76   }
  77
  78   // Check that exactly one ball is on the board
  79   // + at least one piece per color.
  80   static IsGoodPosition(position) {
  81     if (position.length == 0) return false;
  82     const rows = position.split("/");
  83     if (rows.length != V.size.x) return false;
  84     let pieces = { "w": 0, "b": 0 };
  85     const withBall = Object.keys(V.HAS_BALL_DECODE).concat([V.BALL]);
  86     let ballCount = 0;
  87     for (let row of rows) {
  88       let sumElts = 0;
  89       for (let i = 0; i < row.length; i++) {
  90         const lowerRi = row[i].toLowerCase();
  91         if (V.PIECES.includes(lowerRi)) {
  92           if (lowerRi != V.BALL) pieces[row[i] == lowerRi ? "b" : "w"]++;
  93           if (withBall.includes(lowerRi)) ballCount++;
  94           sumElts++;
  95         } else {
  96           const num = parseInt(row[i]);
  97           if (isNaN(num)) return false;
  98           sumElts += num;
  99         }
 100       }
 101       if (sumElts != V.size.y) return false;
 102     }
 103     if (ballCount != 1 || Object.values(pieces).some(v => v == 0))
 104       return false;
 105     return true;
 106   }
 107
 108   getPpath(b) {
 109     let prefix = "";
 110     const withPrefix =
 111       Object.keys(V.HAS_BALL_DECODE)
 112       .concat([V.WILDEBEEST])
 113       .concat(['a']);
 114     if (withPrefix.includes(b[1])) prefix = "Ball/";
 115     return prefix + b;
 116   }
 117
 118   canTake([x1, y1], [x2, y2]) {
 119     // Capture enemy or pass ball to friendly pieces
 120     return (
 121       this.getColor(x1, y1) !== this.getColor(x2, y2) ||
 122       Object.keys(V.HAS_BALL_DECODE).includes(this.board[x1][y1].charAt(1))
 123     );
 124   }
 125
 126   getCheckSquares(color) {
 127     return [];
 128   }
 129
 130   static GenRandInitFen(randomness) {
 131     if (randomness == 0)
 132       return "rnbqkwnbr/ppppppppp/9/9/4a4/9/9/PPPPPPPPP/RNBQKWNBR w 0 -";
 133
 134     let pieces = { w: new Array(9), b: new Array(9) };
 135     for (let c of ["w", "b"]) {
 136       if (c == 'b' && randomness == 1) {
 137         pieces['b'] = pieces['w'];
 138         break;
 139       }
 140
 141       // Get random squares for every piece, totally freely
 142       let positions = shuffle(ArrayFun.range(9));
 143       const composition = ['b', 'b', 'r', 'r', 'n', 'n', 'k', 'q', 'w'];
 144       const rem2 = positions[0] % 2;
 145       if (rem2 == positions[1] % 2) {
 146         // Fix bishops (on different colors)
 147         for (let i=2; i<9; i++) {
 148           if (positions[i] % 2 != rem2)
 149             [positions[1], positions[i]] = [positions[i], positions[1]];
 150         }
 151       }
 152       for (let i = 0; i < 9; i++) pieces[c][positions[i]] = composition[i];
 153     }
 154     return (
 155       pieces["b"].join("") +
 156       "/ppppppppp/9/9/4a4/9/9/PPPPPPPPP/" +
 157       pieces["w"].join("").toUpperCase() +
 158       // En-passant allowed, but no flags
 159       " w 0 -"
 160     );
 161   }
 162
 163   scanKings(fen) {}
 164
 165   static get size() {
 166     return { x: 9, y: 9 };
 167   }
 168
 169   getPiece(i, j) {
 170     const p = this.board[i][j].charAt(1);
 171     if (Object.keys(V.HAS_BALL_DECODE).includes(p))
 172       return V.HAS_BALL_DECODE[p];
 173     return p;
 174   }
 175
 176   static get steps() {
 177     return WildebeestRules.steps;
 178   }
 179
 180   // Because of the ball, getPiece() could be wrong:
 181   // use board[x][y][1] instead (always valid).
 182   getBasicMove([sx, sy], [ex, ey], tr) {
 183     const initColor = this.getColor(sx, sy);
 184     const initPiece = this.board[sx][sy].charAt(1);
 185     let mv = new Move({
 186       appear: [
 187         new PiPo({
 188           x: ex,
 189           y: ey,
 190           c: tr ? tr.c : initColor,
 191           p: tr ? tr.p : initPiece
 192         })
 193       ],
 194       vanish: [
 195         new PiPo({
 196           x: sx,
 197           y: sy,
 198           c: initColor,
 199           p: initPiece
 200         })
 201       ]
 202     });
 203
 204     // Fix "ball holding" indication in case of promotions:
 205     if (!!tr && Object.keys(V.HAS_BALL_DECODE).includes(initPiece))
 206       mv.appear[0].p = V.HAS_BALL_CODE[tr.p];
 207
 208     // The opponent piece disappears if we take it
 209     if (this.board[ex][ey] != V.EMPTY) {
 210       mv.vanish.push(
 211         new PiPo({
 212           x: ex,
 213           y: ey,
 214           c: this.getColor(ex, ey),
 215           p: this.board[ex][ey].charAt(1)
 216         })
 217       );
 218     }
 219
 220     // Post-processing: maybe the ball was taken, or a piece + ball
 221     if (mv.vanish.length == 2) {
 222       if (
 223         // Take the ball?
 224         mv.vanish[1].c == 'a' ||
 225         // Capture a ball-holding piece?
 226         Object.keys(V.HAS_BALL_DECODE).includes(mv.vanish[1].p)
 227       ) {
 228         mv.appear[0].p = V.HAS_BALL_CODE[mv.appear[0].p];
 229       } else if (mv.vanish[1].c == mv.vanish[0].c) {
 230         // Pass the ball: the passing unit does not disappear
 231         mv.appear.push(JSON.parse(JSON.stringify(mv.vanish[0])));
 232         mv.appear[0].p = V.HAS_BALL_CODE[mv.vanish[1].p];
 233         mv.appear[1].p = V.HAS_BALL_DECODE[mv.appear[1].p];
 234       }
 235       // Else: standard capture
 236     }
 237
 238     return mv;
 239   }
 240
 241   // NOTE: if a pawn is captured en-passant, he doesn't hold the ball
 242   // So base implementation is fine.
 243
 244   getPotentialMovesFrom([x, y]) {
 245     if (this.getPiece(x, y) == V.WILDEBEEST)
 246       return this.getPotentialWildebeestMoves([x, y]);
 247     return super.getPotentialMovesFrom([x, y]);
 248   }
 249
 250   getPotentialWildebeestMoves(sq) {
 251     return this.getSlideNJumpMoves(
 252       sq,
 253       V.steps[V.KNIGHT].concat(V.steps[WildebeestRules.CAMEL]),
 254       "oneStep"
 255     );
 256   }
 257
 258   filterValid(moves) {
 259     return moves;
 260   }
 261
 262   // isAttacked: unused here (no checks)
 263
 264   postPlay() {}
 265   postUndo() {}
 266
 267   getCurrentScore() {
 268     // Turn has changed:
 269     const color = V.GetOppCol(this.turn);
 270     const lastRank = (color == "w" ? 0 : 8);
 271     if ([3,4,5].some(
 272       i => {
 273         return (
 274           Object.keys(V.HAS_BALL_DECODE).includes(
 275             this.board[lastRank][i].charAt(1)) &&
 276           this.getColor(lastRank, i) == color
 277         );
 278       }
 279     )) {
 280       // Goal scored!
 281       return color == "w" ? "1-0" : "0-1";
 282     }
 283     if (this.atLeastOneMove()) return "*";
 284     // Stalemate (quite unlikely?)
 285     return "1/2";
 286   }
 287
 288   static get VALUES() {
 289     return {
 290       p: 1,
 291       r: 5,
 292       n: 3,
 293       b: 3,
 294       q: 9,
 295       w: 7,
 296       k: 5,
 297       a: 0 //ball: neutral
 298     };
 299   }
 300
 301   static get SEARCH_DEPTH() {
 302     return 2;
 303   }
 304
 305   evalPosition() {
 306     // Count material:
 307     let evaluation = super.evalPosition();
 308     if (this.board[4][4] == V.BALL)
 309       // Ball not captured yet
 310       return evaluation;
 311     // Ponder depending on ball position
 312     for (let i=0; i<9; i++) {
 313       for (let j=0; j<9; j++) {
 314         if (Object.keys(V.HAS_BALL_DECODE).includes(this.board[i][j][1]))
 315           return evaluation/2 + (this.getColor(i, j) == "w" ? 8 - i : -i);
 316       }
 317     }
 318     return 0; //never reached
 319   }
 320
 321   getNotation(move) {
 322     const finalSquare = V.CoordsToSquare(move.end);
 323     if (move.appear.length == 2)
 324       // A pass: special notation
 325       return V.CoordsToSquare(move.start) + "P" + finalSquare;
 326     const piece = this.getPiece(move.start.x, move.start.y);
 327     if (piece == V.PAWN) {
 328       // Pawn move
 329       let notation = "";
 330       if (move.vanish.length > move.appear.length) {
 331         // Capture
 332         const startColumn = V.CoordToColumn(move.start.y);
 333         notation = startColumn + "x" + finalSquare;
 334       }
 335       else notation = finalSquare;
 336       if (![V.PAWN, V.HAS_BALL_CODE[V.PAWN]].includes(move.appear[0].p)) {
 337         // Promotion
 338         const promotePiece =
 339           V.HAS_BALL_DECODE[move.appear[0].p] || move.appear[0].p;
 340         notation += "=" + promotePiece.toUpperCase();
 341       }
 342       return notation;
 343     }
 344     // Piece movement
 345     return (
 346       piece.toUpperCase() +
 347       (move.vanish.length > move.appear.length ? "x" : "") +
 348       finalSquare
 349     );
 350   }
 351 };