'update'

[vchess.git] / client / src / variants / Wildebeest.js

import { ChessRules } from "@/base_rules";
import { ArrayFun } from "@/utils/array";
import { sample, randInt } from "@/utils/alea";

export const VariantRules = class  WildebeestRules extends ChessRules
{
  static getPpath(b)
  {
    return ([V.CAMEL,V.WILDEBEEST].includes(b[1]) ? "Wildebeest/" : "") + b;
  }

  static get size() { return {x:10,y:11}; }

  static get CAMEL() { return 'c'; }
  static get WILDEBEEST() { return 'w'; }

  static get PIECES()
  {
    return ChessRules.PIECES.concat([V.CAMEL,V.WILDEBEEST]);
  }

  static get steps()
  {
    return Object.assign(
      ChessRules.steps, //add camel moves:
      {'c': [ [-3,-1],[-3,1],[-1,-3],[-1,3],[1,-3],[1,3],[3,-1],[3,1] ]}
    );
  }

  static IsGoodEnpassant(enpassant)
  {
    if (enpassant != "-")
    {
      const squares = enpassant.split(",");
      if (squares.length > 2)
        return false;
      for (let sq of squares)
      {
        const ep = V.SquareToCoords(sq);
        if (isNaN(ep.x) || !V.OnBoard(ep))
          return false;
      }
    }
    return true;
  }

  // There may be 2 enPassant squares (if pawn jump 3 squares)
  getEnpassantFen()
  {
    const L = this.epSquares.length;
    if (!this.epSquares[L-1])
      return "-"; //no en-passant
    let res = "";
    this.epSquares[L-1].forEach(sq => {
      res += V.CoordsToSquare(sq) + ",";
    });
    return res.slice(0,-1); //remove last comma
  }

  // En-passant after 2-sq or 3-sq jumps
  getEpSquare(moveOrSquare)
  {
    if (!moveOrSquare)
      return undefined;
    if (typeof moveOrSquare === "string")
    {
      const square = moveOrSquare;
      if (square == "-")
        return undefined;
      let res = [];
      square.split(",").forEach(sq => {
        res.push(V.SquareToCoords(sq));
      });
      return res;
    }
    // Argument is a move:
    const move = moveOrSquare;
    const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x];
    if (this.getPiece(sx,sy) == V.PAWN && Math.abs(sx - ex) >= 2)
    {
      const step = (ex-sx) / Math.abs(ex-sx);
      let res = [{
        x: sx + step,
        y: sy
      }];
      if (sx + 2*step != ex) //3-squares move
      {
        res.push({
          x: sx + 2*step,
          y: sy
        });
      }
      return res;
    }
    return undefined; //default
  }

  getPotentialMovesFrom([x,y])
  {
    switch (this.getPiece(x,y))
    {
      case V.CAMEL:
        return this.getPotentialCamelMoves([x,y]);
      case V.WILDEBEEST:
        return this.getPotentialWildebeestMoves([x,y]);
      default:
        return super.getPotentialMovesFrom([x,y])
    }
  }

  // Pawns jump 2 or 3 squares, and promote to queen or wildebeest
  getPotentialPawnMoves([x,y])
  {
    const color = this.turn;
    let moves = [];
    const [sizeX,sizeY] = [V.size.x,V.size.y];
    const shiftX = (color == "w" ? -1 : 1);
    const startRanks = (color == "w" ? [sizeX-2,sizeX-3] : [1,2]);
    const lastRank = (color == "w" ? 0 : sizeX-1);
    const finalPieces = x + shiftX == lastRank
      ? [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN]
      : [V.PAWN];

    if (this.board[x+shiftX][y] == V.EMPTY)
    {
      // One square forward
      for (let piece of finalPieces)
        moves.push(this.getBasicMove([x,y], [x+shiftX,y], {c:color,p:piece}));
      if (startRanks.includes(x))
      {
        if (this.board[x+2*shiftX][y] == V.EMPTY)
        {
          // Two squares jump
          moves.push(this.getBasicMove([x,y], [x+2*shiftX,y]));
          if (x==startRanks[0] && this.board[x+3*shiftX][y] == V.EMPTY)
          {
            // Three squares jump
            moves.push(this.getBasicMove([x,y], [x+3*shiftX,y]));
          }
        }
      }
    }
    // Captures
    for (let shiftY of [-1,1])
    {
      if (y + shiftY >= 0 && y + shiftY < sizeY
        && this.board[x+shiftX][y+shiftY] != V.EMPTY
        && this.canTake([x,y], [x+shiftX,y+shiftY]))
      {
        for (let piece of finalPieces)
        {
          moves.push(this.getBasicMove([x,y], [x+shiftX,y+shiftY],
            {c:color,p:piece}));
        }
      }
    }

    // En passant
    const Lep = this.epSquares.length;
    const epSquare = this.epSquares[Lep-1];
    if (!!epSquare)
    {
      for (let epsq of epSquare)
      {
        // TODO: some redundant checks
        if (epsq.x == x+shiftX && Math.abs(epsq.y - y) == 1)
        {
          var enpassantMove = this.getBasicMove([x,y], [epsq.x,epsq.y]);
          // WARNING: the captured pawn may be diagonally behind us,
          // if it's a 3-squares jump and we take on 1st passing square
          const px = (this.board[x][epsq.y] != V.EMPTY ? x : x - shiftX);
          enpassantMove.vanish.push({
            x: px,
            y: epsq.y,
            p: 'p',
            c: this.getColor(px,epsq.y)
          });
          moves.push(enpassantMove);
        }
      }
    }

    return moves;
  }

  // TODO: wildebeest castle

  getPotentialCamelMoves(sq)
  {
    return this.getSlideNJumpMoves(sq, V.steps[V.CAMEL], "oneStep");
  }

  getPotentialWildebeestMoves(sq)
  {
    return this.getSlideNJumpMoves(
      sq, V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]), "oneStep");
  }

  isAttacked(sq, colors)
  {
    return super.isAttacked(sq, colors)
      || this.isAttackedByCamel(sq, colors)
      || this.isAttackedByWildebeest(sq, colors);
  }

  isAttackedByCamel(sq, colors)
  {
    return this.isAttackedBySlideNJump(sq, colors,
      V.CAMEL, V.steps[V.CAMEL], "oneStep");
  }

  isAttackedByWildebeest(sq, colors)
  {
    return this.isAttackedBySlideNJump(sq, colors, V.WILDEBEEST,
      V.steps[V.KNIGHT].concat(V.steps[V.CAMEL]), "oneStep");
  }

  getCurrentScore()
  {
    if (this.atLeastOneMove()) // game not over
      return "*";

    // No valid move: game is lost (stalemate is a win)
    return (this.turn == "w" ? "0-1" : "1-0");
  }

  static get VALUES() {
    return Object.assign(
      ChessRules.VALUES,
      {'c': 3, 'w': 7} //experimental
    );
  }

  static get SEARCH_DEPTH() { return 2; }

  static GenRandInitFen()
  {
    let pieces = { "w": new Array(10), "b": new Array(10) };
    for (let c of ["w","b"])
    {
      let positions = ArrayFun.range(11);

      // Get random squares for bishops + camels (different colors)
      let randIndexes = sample(ArrayFun.range(6), 2)
        .map(i => { return 2*i; });
      let bishop1Pos = positions[randIndexes[0]];
      let camel1Pos = positions[randIndexes[1]];
      // The second bishop (camel) must be on a square of different color
      let randIndexes_tmp = sample(ArrayFun.range(5), 2)
        .map(i => { return 2*i+1; });
      let bishop2Pos = positions[randIndexes_tmp[0]];
      let camel2Pos = positions[randIndexes_tmp[1]];
      for (let idx of randIndexes.concat(randIndexes_tmp)
        .sort((a,b) => { return b-a; })) //largest indices first
      {
        positions.splice(idx, 1);
      }

      let randIndex = randInt(7);
      let knight1Pos = positions[randIndex];
      positions.splice(randIndex, 1);
      randIndex = randInt(6);
      let knight2Pos = positions[randIndex];
      positions.splice(randIndex, 1);

      randIndex = randInt(5);
      let queenPos = positions[randIndex];
      positions.splice(randIndex, 1);

      // Random square for wildebeest
      randIndex = randInt(4);
      let wildebeestPos = positions[randIndex];
      positions.splice(randIndex, 1);

      let rook1Pos = positions[0];
      let kingPos = positions[1];
      let rook2Pos = positions[2];

      pieces[c][rook1Pos] = 'r';
      pieces[c][knight1Pos] = 'n';
      pieces[c][bishop1Pos] = 'b';
      pieces[c][queenPos] = 'q';
      pieces[c][camel1Pos] = 'c';
      pieces[c][camel2Pos] = 'c';
      pieces[c][wildebeestPos] = 'w';
      pieces[c][kingPos] = 'k';
      pieces[c][bishop2Pos] = 'b';
      pieces[c][knight2Pos] = 'n';
      pieces[c][rook2Pos] = 'r';
    }
    return pieces["b"].join("") +
      "/ppppppppppp/11/11/11/11/11/11/PPPPPPPPPPP/" +
      pieces["w"].join("").toUpperCase() +
      " w 0 1111 -";
  }
}