client/src/variants/Football.js

   1 import { ChessRules } from "@/base_rules";
   2 import { randInt, shuffle } from "@/utils/alea";
   3 import { ArrayFun } from "@/utils/array";
   4
   5 export class FootballRules extends ChessRules {
   6
   7   static get HasEnpassant() {
   8     return false;
   9   }
  10
  11   static get HasFlags() {
  12     return false;
  13   }
  14
  15   static get size() {
  16     return { x: 9, y: 9 };
  17   }
  18
  19   static get Lines() {
  20     return [
  21       // White goal:
  22       [[0, 4], [0, 5]],
  23       [[0, 5], [1, 5]],
  24       [[1, 4], [0, 4]],
  25       // Black goal:
  26       [[9, 4], [9, 5]],
  27       [[9, 5], [8, 5]],
  28       [[8, 4], [9, 4]]
  29     ];
  30   }
  31
  32   static get BALL() {
  33     // 'b' is already taken:
  34     return "aa";
  35   }
  36
  37   // Check that exactly one ball is on the board
  38   // + at least one piece per color.
  39   static IsGoodPosition(position) {
  40     if (position.length == 0) return false;
  41     const rows = position.split("/");
  42     if (rows.length != V.size.x) return false;
  43     let pieces = { "w": 0, "b": 0 };
  44     let ballCount = 0;
  45     for (let row of rows) {
  46       let sumElts = 0;
  47       for (let i = 0; i < row.length; i++) {
  48         const lowerRi = row[i].toLowerCase();
  49         if (!!lowerRi.match(/^[a-z]$/)) {
  50           if (V.PIECES.includes(lowerRi))
  51             pieces[row[i] == lowerRi ? "b" : "w"]++;
  52           else if (lowerRi == 'a') ballCount++;
  53           else return false;
  54           sumElts++;
  55         }
  56         else {
  57           const num = parseInt(row[i], 10);
  58           if (isNaN(num)) return false;
  59           sumElts += num;
  60         }
  61       }
  62       if (sumElts != V.size.y) return false;
  63     }
  64     if (ballCount != 1 || Object.values(pieces).some(v => v == 0))
  65       return false;
  66     return true;
  67   }
  68
  69   static board2fen(b) {
  70     if (b == V.BALL) return 'a';
  71     return ChessRules.board2fen(b);
  72   }
  73
  74   static fen2board(f) {
  75     if (f == 'a') return V.BALL;
  76     return ChessRules.fen2board(f);
  77   }
  78
  79   getPpath(b) {
  80     if (b == V.BALL) return "Football/ball";
  81     return b;
  82   }
  83
  84   canIplay(side, [x, y]) {
  85     return (
  86       side == this.turn &&
  87       (this.board[x][y] == V.BALL || this.getColor(x, y) == side)
  88     );
  89   }
  90
  91   // No checks or king tracking etc. But, track ball
  92   setOtherVariables() {
  93     // Stack of "kicked by" coordinates, to avoid infinite loops
  94     this.kickedBy = [ {} ];
  95     this.subTurn = 1;
  96     this.ballPos = [-1, -1];
  97     for (let i=0; i < V.size.x; i++) {
  98       for (let j=0; j< V.size.y; j++) {
  99         if (this.board[i][j] == V.BALL) {
 100           this.ballPos = [i, j];
 101           return;
 102         }
 103       }
 104     }
 105   }
 106
 107   static GenRandInitFen(options) {
 108     if (options.randomness == 0)
 109       return "rnbq1knbr/9/9/9/4a4/9/9/9/RNBQ1KNBR w 0";
 110
 111     let pieces = { w: new Array(8), b: new Array(8) };
 112     for (let c of ["w", "b"]) {
 113       if (c == 'b' && options.randomness == 1) {
 114         pieces['b'] = pieces['w'];
 115         break;
 116       }
 117
 118       // Get random squares for every piece, totally freely
 119       let positions = shuffle(ArrayFun.range(8));
 120       const composition = ['b', 'b', 'r', 'r', 'n', 'n', 'k', 'q'];
 121       // Fix bishops (on different colors)
 122       const realOddity =
 123         (pos) => { return (pos <= 3 ? pos % 2 : (pos + 1) % 2); };
 124       const rem2 = realOddity(positions[0]);
 125       if (rem2 == realOddity(positions[1])) {
 126         for (let i=2; i<8; i++) {
 127           if (realOddity(positions[i]) != rem2) {
 128             [positions[1], positions[i]] = [positions[i], positions[1]];
 129             break;
 130           }
 131         }
 132       }
 133       for (let i = 0; i < 8; i++) pieces[c][positions[i]] = composition[i];
 134     }
 135     const piecesB = pieces["b"].join("") ;
 136     const piecesW = pieces["w"].join("").toUpperCase();
 137     return (
 138       piecesB.substr(0, 4) + "1" + piecesB.substr(4) +
 139       "/9/9/9/4a4/9/9/9/" +
 140       piecesW.substr(0, 4) + "1" + piecesW.substr(4) +
 141       " w 0"
 142     );
 143   }
 144
 145   tryKickFrom([x, y]) {
 146     const bp = this.ballPos;
 147     const emptySquare = (i, j) => {
 148       return V.OnBoard(i, j) && this.board[i][j] == V.EMPTY;
 149     };
 150     // Kick the (adjacent) ball from x, y with current turn:
 151     const step = [bp[0] - x, bp[1] - y];
 152     const piece = this.getPiece(x, y);
 153     let moves = [];
 154     if (piece == V.KNIGHT) {
 155       // The knight case is particular
 156       V.steps[V.KNIGHT].forEach(s => {
 157         const [i, j] = [bp[0] + s[0], bp[1] + s[1]];
 158         if (
 159           V.OnBoard(i, j) &&
 160           this.board[i][j] == V.EMPTY &&
 161           (
 162             // In a corner? Then, allow all ball moves
 163             ([0, 8].includes(bp[0]) && [0, 8].includes(bp[1])) ||
 164             // Do not end near the knight
 165             (Math.abs(i - x) >= 2 || Math.abs(j - y) >= 2)
 166           )
 167         ) {
 168           moves.push(super.getBasicMove(bp, [i, j]));
 169         }
 170       });
 171     }
 172     else {
 173       let compatible = false,
 174           oneStep = false;
 175       switch (piece) {
 176         case V.ROOK:
 177           compatible = (step[0] == 0 || step[1] == 0);
 178           break;
 179         case V.BISHOP:
 180           compatible = (step[0] != 0 && step[1] != 0);
 181           break;
 182         case V.QUEEN:
 183           compatible = true;
 184           break;
 185         case V.KING:
 186           compatible = true;
 187           oneStep = true;
 188           break;
 189       }
 190       if (!compatible) return [];
 191       let [i, j] = [bp[0] + step[0], bp[1] + step[1]];
 192       const horizontalStepOnGoalRow =
 193         ([0, 8].includes(bp[0]) && step.some(s => s == 0));
 194       if (
 195         emptySquare(i, j) &&
 196         (this.movesCount >= 2 || j != 4 || ![0, 8].includes(i)) &&
 197         (!horizontalStepOnGoalRow || j != 4)
 198       ) {
 199         moves.push(super.getBasicMove(bp, [i, j]));
 200         if (!oneStep) {
 201           do {
 202             i += step[0];
 203             j += step[1];
 204             if (!emptySquare(i, j)) break;
 205             if (
 206               (this.movesCount >= 2 || j != 4 || ![0, 8].includes(i)) &&
 207               (!horizontalStepOnGoalRow || j != 4)
 208             ) {
 209               moves.push(super.getBasicMove(bp, [i, j]));
 210             }
 211           } while (true);
 212         }
 213       }
 214       // Try the other direction (TODO: experimental)
 215       [i, j] = [bp[0] - 2*step[0], bp[1] - 2*step[1]];
 216       if (
 217         emptySquare(i, j) &&
 218         (this.movesCount >= 2 || j != 4 || ![0, 8].includes(i)) &&
 219         (!horizontalStepOnGoalRow || j != 4)
 220       ) {
 221         moves.push(super.getBasicMove(bp, [i, j]));
 222         if (!oneStep) {
 223           do {
 224             i -= step[0];
 225             j -= step[1];
 226             if (!emptySquare(i, j)) break;
 227             if (
 228               (this.movesCount >= 2 || j != 4 || ![0, 8].includes(i)) &&
 229               (!horizontalStepOnGoalRow || j != 4)
 230             ) {
 231               moves.push(super.getBasicMove(bp, [i, j]));
 232             }
 233           } while (true);
 234         }
 235       }
 236     }
 237     const kickedFrom = x + "-" + y;
 238     moves.forEach(m => m.start.by = kickedFrom)
 239     return moves;
 240   }
 241
 242   getPotentialMovesFrom([x, y], computer) {
 243     const piece = this.getPiece(x, y);
 244     if (V.PIECES.includes(piece)) {
 245       if (this.subTurn > 1) return [];
 246       const moves = super.getPotentialMovesFrom([x, y])
 247                     .filter(m => m.end.y != 4 || ![0, 8].includes(m.end.x));
 248       // If bishop stuck in a corner: allow to jump over the next obstacle
 249       if (
 250         moves.length == 0 && piece == V.BISHOP &&
 251         [0, 8].includes(x) && [0, 8].includes(y)
 252       ) {
 253         const indX = x == 0 ? [1, 2] : [7, 6];
 254         const indY = y == 0 ? [1, 2] : [7, 6];
 255         if (
 256           this.board[indX[0]][indY[0]] != V.EMPTY &&
 257           this.board[indX[1]][indY[1]] == V.EMPTY
 258         ) {
 259           return [super.getBasicMove([x, y], [indX[1], indY[1]])];
 260         }
 261       }
 262       return moves;
 263     }
 264     // Kicking the ball: look for adjacent pieces.
 265     const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
 266     const c = this.turn;
 267     let moves = [];
 268     let kicks = {};
 269     let adjacentPieces = false;
 270     for (let s of steps) {
 271       const [i, j] = [x + s[0], y + s[1]];
 272       if (
 273         V.OnBoard(i, j) &&
 274         this.board[i][j] != V.EMPTY &&
 275         this.getColor(i, j) == c
 276       ) {
 277         const kmoves = this.tryKickFrom([i, j]);
 278         kmoves.forEach(km => {
 279           const key = V.CoordsToSquare(km.start) + V.CoordsToSquare(km.end);
 280           if (!kicks[key]) {
 281             moves.push(km);
 282             kicks[key] = true;
 283           }
 284         });
 285         if (!adjacentPieces) adjacentPieces = true;
 286       }
 287     }
 288     if (adjacentPieces) {
 289       // Add the "end" move (even if no valid kicks)
 290       outerLoop: for (let i=0; i < V.size.x; i++) {
 291         for (let j=0; j < V.size.y; j++) {
 292           if (this.board[i][j] != V.EMPTY && this.getColor(i, j) == c) {
 293             moves.push({
 294               appear: [], vanish: [],
 295               start: { x: x, y: y }, end: { x: i, y: j }
 296             });
 297             if (computer) break outerLoop; //no choice for computer
 298           }
 299         }
 300       }
 301     }
 302     return moves;
 303   }
 304
 305   canTake() {
 306     return false;
 307   }
 308
 309   // Extra arg "computer" to avoid trimming all redundant pass moves:
 310   getAllPotentialMoves(computer) {
 311     const color = this.turn;
 312     let potentialMoves = [];
 313     for (let i = 0; i < V.size.x; i++) {
 314       for (let j = 0; j < V.size.y; j++) {
 315         if (this.board[i][j] != V.EMPTY && this.getColor(i, j) == color) {
 316           Array.prototype.push.apply(
 317             potentialMoves,
 318             this.getPotentialMovesFrom([i, j], computer)
 319           );
 320         }
 321       }
 322     }
 323     return potentialMoves;
 324   }
 325
 326   getAllValidMoves() {
 327     return this.filterValid(this.getAllPotentialMoves("computer"));
 328   }
 329
 330   filterValid(moves) {
 331     const L = this.kickedBy.length;
 332     const kb = this.kickedBy[L-1];
 333     return moves.filter(m => !m.start.by || !kb[m.start.by]);
 334   }
 335
 336   getCheckSquares() {
 337     return [];
 338   }
 339
 340   allowAnotherPass(color) {
 341     // Two cases: a piece moved, or the ball moved.
 342     // In both cases, check our pieces and ball proximity,
 343     // so the move played doesn't matter (if ball position updated)
 344     const bp = this.ballPos;
 345     const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
 346     for (let s of steps) {
 347       const [i, j] = [this.ballPos[0] + s[0], this.ballPos[1] + s[1]];
 348       if (
 349         V.OnBoard(i, j) &&
 350         this.board[i][j] != V.EMPTY &&
 351         this.getColor(i, j) == color
 352       ) {
 353         return true; //potentially...
 354       }
 355     }
 356     return false;
 357   }
 358
 359   prePlay(move) {
 360     if (move.appear[0].p == 'a')
 361       this.ballPos = [move.appear[0].x, move.appear[0].y];
 362   }
 363
 364   play(move) {
 365     // Special message saying "passes are over"
 366     const passesOver = (move.vanish.length == 0);
 367     if (!passesOver) {
 368       this.prePlay(move);
 369       V.PlayOnBoard(this.board, move);
 370     }
 371     move.turn = [this.turn, this.subTurn]; //easier undo
 372     if (passesOver || !this.allowAnotherPass(this.turn)) {
 373       this.turn = V.GetOppCol(this.turn);
 374       this.subTurn = 1;
 375       this.movesCount++;
 376       this.kickedBy.push( {} );
 377     }
 378     else {
 379       this.subTurn++;
 380       if (!!move.start.by) {
 381         const L = this.kickedBy.length;
 382         this.kickedBy[L-1][move.start.by] = true;
 383       }
 384     }
 385   }
 386
 387   undo(move) {
 388     const passesOver = (move.vanish.length == 0);
 389     if (move.turn[0] != this.turn) {
 390       [this.turn, this.subTurn] = move.turn;
 391       this.movesCount--;
 392       this.kickedBy.pop();
 393     }
 394     else {
 395       this.subTurn--;
 396       if (!!move.start.by) {
 397         const L = this.kickedBy.length;
 398         delete this.kickedBy[L-1][move.start.by];
 399       }
 400     }
 401     if (!passesOver) {
 402       V.UndoOnBoard(this.board, move);
 403       this.postUndo(move);
 404     }
 405   }
 406
 407   postUndo(move) {
 408     if (move.vanish[0].p == 'a')
 409       this.ballPos = [move.vanish[0].x, move.vanish[0].y];
 410   }
 411
 412   getCurrentScore() {
 413     if (this.board[0][4] == V.BALL) return "1-0";
 414     if (this.board[8][4] == V.BALL) return "0-1";
 415     return "*";
 416   }
 417
 418   getComputerMove() {
 419     let initMoves = this.getAllValidMoves();
 420     if (initMoves.length == 0) return null;
 421     let moves = JSON.parse(JSON.stringify(initMoves));
 422     let mvArray = [];
 423     let mv = null;
 424     // Just play random moves (for now at least. TODO?)
 425     const c = this.turn;
 426     while (moves.length > 0) {
 427       mv = moves[randInt(moves.length)];
 428       mvArray.push(mv);
 429       this.play(mv);
 430       if (mv.vanish.length == 1 && this.allowAnotherPass(c))
 431         // Potential kick
 432         moves = this.getPotentialMovesFrom(this.ballPos);
 433       else break;
 434     }
 435     for (let i = mvArray.length - 1; i >= 0; i--) this.undo(mvArray[i]);
 436     return (mvArray.length > 1 ? mvArray : mvArray[0]);
 437   }
 438
 439   // NOTE: evalPosition() is wrong, but unused since bot plays at random
 440
 441   getNotation(move) {
 442     if (move.vanish.length == 0) return "pass";
 443     if (move.vanish[0].p != 'a') return super.getNotation(move);
 444     // Kick: simple notation (TODO?)
 445     return V.CoordsToSquare(move.end);
 446   }
 447
 448 };