private bool IsInReach(Square square)
{
if (square.IsOccupied() &&
square.Piece.Color == Color)
{
return false;
}
return IsFreeBetween(square);
}
private IEnumerable<Square> GetSquaresInDirection(Square square, Func<Square, Square> directionFunc)
{
var squareInDirection = directionFunc(square);
var squares = new List<Square>();
if (CanMoveTo(squareInDirection))
{
squares.Add(squareInDirection);
if (squareInDirection.IsFree())
{
squares.AddRange(GetSquaresInDirection(squareInDirection, directionFunc));
}
}
return squares;
}
protected bool IsKingInCheckAfterMove(SquareIdentifier squareIdentifier)
{
var board = CurrentSquare.Board;
var squareBefore = CurrentSquare;
var squareAfter = board[squareIdentifier];
var pieceAtNewSquare = squareAfter.Piece;
CurrentSquare.Piece = null;
CurrentSquare = squareAfter;
squareAfter.Piece = this;
var isInCheckAfterMove = board.IsInCheck(Color);
squareBefore.Piece = this;
squareAfter.Piece = pieceAtNewSquare;
CurrentSquare = squareBefore;
return isInCheckAfterMove;
}
private bool IsFreeBetween(Square square)
{
if (CurrentSquare.Identifier.Rank == square.Identifier.Rank)
{
var oneCloserSquare = square.Identifier.File < CurrentSquare.Identifier.File
? square.SquareToTheRight
: square.SquareToTheLeft;
return oneCloserSquare.Equals(CurrentSquare) ||
(oneCloserSquare.IsFree() && IsFreeBetween(oneCloserSquare));
}
if (CurrentSquare.Identifier.File == square.Identifier.File)
{
var oneCloserSquare = square.Identifier.Rank < CurrentSquare.Identifier.Rank
? square.SquareAbove
: square.SquareBelow;
return oneCloserSquare.Equals(CurrentSquare) ||
(oneCloserSquare.IsFree() && IsFreeBetween(oneCloserSquare));
}
return false;
}
public Board()
{
History = new MoveHistory();
for (var i = 0; i < 8; i++)
{
for (var j = 0; j < 8; j++)
{
_squares[i, j] = new Square();
}
}
InitializePosition("a1", new Rook { Color = Army.White });
InitializePosition("b1", new Knight { Color = Army.White });
InitializePosition("c1", new Bishop { Color = Army.White });
InitializePosition("d1", new Queen { Color = Army.White });
InitializePosition("e1", new King { Color = Army.White });
InitializePosition("f1", new Bishop { Color = Army.White });
InitializePosition("g1", new Knight { Color = Army.White });
InitializePosition("h1", new Rook { Color = Army.White });
InitializePosition("a2", new Pawn { Color = Army.White });
InitializePosition("b2", new Pawn { Color = Army.White });
InitializePosition("c2", new Pawn { Color = Army.White });
InitializePosition("d2", new Pawn { Color = Army.White });
InitializePosition("e2", new Pawn { Color = Army.White });
InitializePosition("f2", new Pawn { Color = Army.White });
InitializePosition("g2", new Pawn { Color = Army.White });
InitializePosition("h2", new Pawn { Color = Army.White });
InitializePosition("a3", null);
InitializePosition("b3", null);
InitializePosition("c3", null);
InitializePosition("d3", null);
InitializePosition("e3", null);
InitializePosition("f3", null);
InitializePosition("g3", null);
InitializePosition("h3", null);
InitializePosition("a4", null);
InitializePosition("b4", null);
InitializePosition("c4", null);
InitializePosition("d4", null);
InitializePosition("e4", null);
InitializePosition("f4", null);
InitializePosition("g4", null);
InitializePosition("h4", null);
InitializePosition("a5", null);
InitializePosition("b5", null);
InitializePosition("c5", null);
InitializePosition("d5", null);
InitializePosition("e5", null);
InitializePosition("f5", null);
InitializePosition("g5", null);
InitializePosition("h5", null);
InitializePosition("a6", null);
InitializePosition("b6", null);
InitializePosition("c6", null);
InitializePosition("d6", null);
InitializePosition("e6", null);
InitializePosition("f6", null);
InitializePosition("g6", null);
InitializePosition("h6", null);
InitializePosition("a7", new Pawn { Color = Army.Black });
InitializePosition("b7", new Pawn { Color = Army.Black });
InitializePosition("c7", new Pawn { Color = Army.Black });
InitializePosition("d7", new Pawn { Color = Army.Black });
InitializePosition("e7", new Pawn { Color = Army.Black });
InitializePosition("f7", new Pawn { Color = Army.Black });
InitializePosition("g7", new Pawn { Color = Army.Black });
InitializePosition("h7", new Pawn { Color = Army.Black });
InitializePosition("a8", new Rook { Color = Army.Black });
InitializePosition("b8", new Knight { Color = Army.Black });
InitializePosition("c8", new Bishop { Color = Army.Black });
InitializePosition("d8", new Queen { Color = Army.Black });
InitializePosition("e8", new King { Color = Army.Black });
InitializePosition("f8", new Bishop { Color = Army.Black });
InitializePosition("g8", new Knight { Color = Army.Black });
InitializePosition("h8", new Rook { Color = Army.Black });
}
private bool CanMoveTo(Square square)
{
return square != null && (square.IsFree() || square.Piece.Color != Color);
}
private bool IsPromotionSquare(Square square)
{
return Color == Army.White
? square.Identifier.Rank == '8'
: square.Identifier.Rank == '1';
}
private bool IsEnPassantMove(Square move)
{
if (move.Identifier.Rank == '6')
{
var lastMove = move.Board.History.Moves.LastOrDefault();
if (lastMove != null)
{
if (lastMove.MovedPiece is Pawn && lastMove.From.File == move.Identifier.File && lastMove.To.File == move.Identifier.File)
{
if (Color == Army.White && lastMove.From.Rank == '7' && lastMove.To.Rank == '5')
{
return true;
}
if (lastMove.From.Rank == '2' && lastMove.To.Rank == '4')
{
return true;
}
}
}
}
return false;
}
private Square GetMoveOneForwardSquare(Square from)
{
var newSquare = Color == Army.White
? from.SquareAbove
: from.SquareBelow;
return newSquare != null && newSquare.IsFree()
? newSquare
: null;
}