internal static bool IsPlayerInCheck(Player player, ChessGame board)
{
Player opponent = RevertPlayer(player);
IEnumerable <Square> opponentOwnedSquares = s_allSquares.Where(sq => board[sq.File, sq.Rank]?.Owner == opponent);
Square playerKingSquare = s_allSquares.First(sq => new King(player).Equals(board[sq.File, sq.Rank]));
return((from opponentOwnedSquare in opponentOwnedSquares
let piece = board[opponentOwnedSquare.File, opponentOwnedSquare.Rank]
let move = new Move(opponentOwnedSquare, playerKingSquare, opponent, PawnPromotion.Queen) // Added PawnPromotion in the Move because omitting it causes a bug when King in its rank is in a check by a pawn.
where piece.IsValidGameMove(move, board)
select piece).Any());
}
/* TODO: Still not sure where to implement it, but I may need methods:
* TODO: bool CanClaimDraw + bool ClaimDraw + OfferDraw
*/
/// <summary>Gets the valid moves of the given <see cref="ChessGame"/>.</summary>
/// <param name="board">The <see cref="ChessGame"/> that you want to get its valid moves.</param>
/// <returns>Returns a list of the valid moves.</returns>
public static List <Move> GetValidMoves(ChessGame board)
{
Player player = board.WhoseTurn;
var validMoves = new List <Move>();
IEnumerable <Square> playerOwnedSquares = s_allSquares.Where(sq => board[sq]?.Owner == player);
Square[] nonPlayerOwnedSquares = s_allSquares.Where(sq => board[sq]?.Owner != player).ToArray(); // Converting to array to avoid "Possible multiple enumeration" as suggested by ReSharper.
foreach (Square playerOwnedSquare in playerOwnedSquares)
{
validMoves.AddRange(nonPlayerOwnedSquares
.Select(nonPlayerOwnedSquare => new Move(playerOwnedSquare, nonPlayerOwnedSquare, player))
.Where(move => ChessGame.IsValidMove(move, board)));
}
return(validMoves);
}
/// <summary>Gets the valid moves of the given <see cref="ChessGame"/> that has a specific given source <see cref="Square"/>.</summary>
/// <param name="source">The source <see cref="Square"/> that you're looking for its valid moves.</param>
/// <param name="board">The <see cref="ChessGame"/> that you want to get its valid moves from the specified square.</param>
/// <returns>Returns a list of the valid moves that has the given source square.</returns>
///
public static List <Move> GetValidMovesOfSourceSquare(Square source, ChessGame board)
{
var validMoves = new List <Move>();
Piece piece = board[source];
if (piece == null || piece.Owner != board.WhoseTurn)
{
return(validMoves);
}
Player player = piece.Owner;
Square[] nonPlayerOwnedSquares = s_allSquares.Where(sq => board[sq]?.Owner != player).ToArray();
validMoves.AddRange(nonPlayerOwnedSquares
.Select(nonPlayerOwnedSquare => new Move(source, nonPlayerOwnedSquare, player, PawnPromotion.Queen)) // If promoteTo is null, valid pawn promotion will cause exception. Need to implement this better and cleaner in the future.
.Where(move => ChessGame.IsValidMove(move, board)));
return(validMoves);
}
/* TODO: Still not sure where to implement it, but I may need methods:
* TODO: bool CanClaimDraw + bool ClaimDraw + OfferDraw
*/
/// <summary>Gets the valid moves of the given <see cref="ChessGame"/>.</summary>
/// <param name="board">The <see cref="ChessGame"/> that you want to get its valid moves.</param>
/// <returns>Returns a list of the valid moves.</returns>
public static List <Move> GetValidMoves(ChessGame board)
{
// Although nullable is enabled and board is non-nullable ref type, this check is needed
// because this is a public method that can be used by an application that doesn't have
// nullable enabled.
_ = board ?? throw new ArgumentNullException(nameof(board));
Player player = board.WhoseTurn;
var validMoves = new List <Move>();
IEnumerable <Square> playerOwnedSquares = s_allSquares.Where(sq => board[sq.File, sq.Rank]?.Owner == player);
Square[] nonPlayerOwnedSquares = s_allSquares.Where(sq => board[sq.File, sq.Rank]?.Owner != player).ToArray(); // Converting to array to avoid "Possible multiple enumeration" as suggested by ReSharper.
foreach (Square playerOwnedSquare in playerOwnedSquares)
{
validMoves.AddRange(nonPlayerOwnedSquares
.Select(nonPlayerOwnedSquare => new Move(playerOwnedSquare, nonPlayerOwnedSquare, player))
.Where(move => ChessGame.IsValidMove(move, board)));
}
return(validMoves);
}
internal Square(ChessGame game, int file, int rank)
{
Game = game;
FileIndex = file;
RankIndex = rank;
}
