ChessDotNet.Piece.GetFenCharacter C# (CSharp) Method

        public abstract char GetFenCharacter();
        public abstract bool IsValidMove(Move move, ChessGame game);

        protected virtual string GetSanForMove(Move move, Piece movingPiece, bool isCapture, CastlingType castle, List <Position> ambiguities)
        {
            if (castle == CastlingType.KingSide)
            {
                return("O-O");
            }
            if (castle == CastlingType.QueenSide)
            {
                return("O-O-O");
            }

            bool needsUnambigFile = false;
            bool needsUnambigRank = false;

            if (ambiguities.Count > 0)
            {
                foreach (Position amb in ambiguities)
                {
                    if (amb.Rank == move.OriginalPosition.Rank)
                    {
                        needsUnambigFile = true;
                    }
                    if (amb.File == move.OriginalPosition.File)
                    {
                        needsUnambigRank = true;
                    }
                }
                if (!needsUnambigFile && !needsUnambigRank)
                {
                    needsUnambigFile = true;
                }
            }

            StringBuilder sanBuilder = new StringBuilder();

            if (!(movingPiece is Pawn))
            {
                sanBuilder.Append(char.ToUpperInvariant(movingPiece.GetFenCharacter()));
            }
            else if (isCapture)
            {
                sanBuilder.Append(move.OriginalPosition.File.ToString().ToLowerInvariant());
                needsUnambigFile = false;
                needsUnambigRank = false;
            }
            if (needsUnambigFile)
            {
                sanBuilder.Append(move.OriginalPosition.File.ToString().ToLowerInvariant());
            }
            if (needsUnambigRank)
            {
                sanBuilder.Append(move.OriginalPosition.Rank.ToString());
            }
            if (isCapture)
            {
                sanBuilder.Append("x");
            }
            sanBuilder.Append(move.NewPosition.ToString().ToLowerInvariant());
            if (move.Promotion.HasValue)
            {
                sanBuilder.Append("=");
                sanBuilder.Append(move.Promotion.Value);
            }
            if (IsWinner(ChessUtilities.GetOpponentOf(WhoseTurn)))
            {
                sanBuilder.Append("#");
            }
            else if (IsInCheck(WhoseTurn))
            {
                sanBuilder.Append("+");
            }
            return(sanBuilder.ToString());
        }