/// <summary>
/// Loads ChessBoard from Forsyth-Edwards Notation<br/>
/// ex.:<br/>
/// rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1
/// </summary>
/// <param name="fen">FEN string to load</param>
/// <returns>ChessBoard with according positions</returns>
/// <exception cref="ChessArgumentException">Given FEN string didn't match the Regex pattern</exception>
public static ChessBoard LoadFromFen(string fen)
{
var(succeeded, exception) = FenBoardBuilder.TryLoad(fen, out var builder);
if (!succeeded && exception is not null)
{
throw exception;
}
return(BuildBoardFromFen(builder));
}
/// <summary>
/// Tries to load
/// ChessBoard from Forsyth-Edwards Notation<br/>
/// ex.:<br/>
/// rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1
/// </summary>
/// <param name="fen">FEN string to load</param>
/// <param name="board">Result with loaded board</param>
/// <returns>Whether load is succeeded</returns>
public static bool TryLoadFromFen(string fen, [NotNullWhen(true)] out ChessBoard?board)
{
var(succeeded, _) = FenBoardBuilder.TryLoad(fen, out var builder);
if (!succeeded)
{
board = null;
return(false);
}
board = BuildBoardFromFen(builder);
return(true);
}
public static (bool succeeded, ChessException?exception) TryLoad(string pgn, out ChessBoard?board)
{
board = new();
var headersMatches = Regexes.regexHeaders.Matches(pgn);
if (headersMatches.Count > 0)
{
// Extracting headers
for (int i = 0; i < headersMatches.Count; i++)
{
// [Black "Geras1mleo"]
// Groups[1] = Black
// Groups[2] = Geras1mleo
board.headers.Add(headersMatches[i].Groups[1].Value,
headersMatches[i].Groups[2].Value);
}
}
// San move can occur in header ex. in nickname of player => remove headers from string
pgn = Regexes.regexHeaders.Replace(pgn, "");
// Loading fen if exist
if (board.headers.TryGetValue("FEN", out var fen))
{
var(succeeded, exception) = FenBoardBuilder.TryLoad(fen, out board.FenBuilder);
if (!succeeded)
{
board = null;
return(false, exception);
}
board.pieces = board.FenBuilder.Pieces;
board.HandleKingChecked();
board.HandleEndGame();
if (board.IsEndGame)
{
return(true, null);
}
}
// Remove all alternatives
pgn = Regexes.regexAlternatives.Replace(pgn, "");
// Remove all comments
pgn = Regexes.regexComments.Replace(pgn, "");
// Todo Save Alternative moves(bracnhes) and Comments for moves
var movesMatches = Regexes.regexSanMoves.Matches(pgn);
// Execute all found moves
for (int i = 0; i < movesMatches.Count; i++)
{
var(succeeded, exception) = SanBuilder.TryParse(board, movesMatches[i].Value, out var move, true);
if (!succeeded)
{
board = null;
return(false, exception);
}
// If san parsing succeeded => move is valid
board.executedMoves.Add(move);
board.DropPieceToNewPosition(move);
board.moveIndex = board.executedMoves.Count - 1;
}
board.HandleKingChecked();
board.HandleEndGame();
// If not actual end game but game is in fact ended => someone resigned
if (!board.IsEndGame)
{
if (pgn.Contains("1-0"))
{
board.Resign(PieceColor.Black);
}
else if (pgn.Contains("0-1"))
{
board.Resign(PieceColor.White);
}
else if (pgn.Contains("1/2-1/2"))
{
board.Draw();
}
}
return(true, null);
}
