TableParser

using System.Collections.Generic;
using System.Linq;

namespace TableParser
{
    public class FieldsParserTask
    {
        public static List<string> ParseLine(string line)
        {
            var list = new List<string>();
            if (line.Length == 0)
                return list;
            var quoteIndex = 0;
            var simple = GetFirstFieldType(line);
            MainBlock(line, list, quoteIndex, simple);
            return list;
        }

        public static void MainBlock(string line, List<string> list, int quoteIndex, bool simple)
        {
            for (var i = 0; i < line.Length; i++)
            {
                if (simple)
                {
                    i = GetIndexNextToToken(line, quoteIndex);
                    if (i == -1)
                    {
                        list = AddFieldWithoutClosingQuote(line, list, quoteIndex);
                        return;
                    }
                    else
                        if (i != line.IndexOfAny(new char[] { '\'', '\"' }))
                            i += quoteIndex + 1;
                    simple = false;
                    list = AddSimpleField(line, list, quoteIndex, i);
                    quoteIndex = i;
                    continue;
                }
                if (!simple)
                    ComplexField(line, list, ref quoteIndex, ref simple, ref i);
            }
        }

        private static void ComplexField(string line, List<string> list, ref int quoteIndex, ref bool simple, ref int i)
        {
            for (var k = quoteIndex + 1; k < line.Length; k++)
            {
                if (line[k] == '\\')
                {
                    k++;
                    continue;
                }
                if (line[k] == line[quoteIndex])
                {
                    i = k;
                    list.Add(DeleteSlash(line.Substring(quoteIndex + 1, k - quoteIndex - 1)));
                    quoteIndex = k;
                    simple = true;
                    break;
                }
                if (k + 1 == line.Length)
                {
                    i = line.Length - 1;
                    list.Add(DeleteSlash(line.Substring(quoteIndex + 1)));
                    break;
                }
            }
        }

        public static List<string> AddSimpleField(string line, List<string> list, int quoteIndex, int i)
        {
            if (quoteIndex == 0)
                list.AddRange(GetSplitedSimpleField(line.Substring(quoteIndex, i - quoteIndex)));
            else
                list.AddRange(GetSplitedSimpleField(line.Substring(quoteIndex + 1, i - quoteIndex - 1)));
            return list;
        }

        public static List<string> AddFieldWithoutClosingQuote(string line, List<string> list, int quoteIndex)
        {
            if (quoteIndex != 0)
                quoteIndex++;
            list.AddRange(line.Substring(quoteIndex)
                .Split(' ')
                .Where(x => x != ""));
            return list;
        }

        public static int GetIndexNextToToken(string line, int quoteIndex)
        {
            var i = 0;
            if (quoteIndex != 0)
                i = line.Substring(quoteIndex + 1).IndexOfAny(new char[] { '\'', '\"' });
            else
                i = line.IndexOfAny(new char[] { '\'', '\"' });
            return i;
        }

        public static bool GetFirstFieldType(string line)
        {
            var simple = true;
            if (line[0] == '\'' || line[0] == '\"')
                simple = false;
            return simple;
        }

        public static List<string> GetSplitedSimpleField(string line)
        {
            return line
                     .ToString()
                     .Split(' ')
                     .Where(x => x != "")
                     .ToList();
        }

        public static string DeleteSlash(string line)
        {
            return line
                .Replace("\\\\", "\\")
                .Replace("\\'", "'")
                .Replace("\\\"", "\"");
        }
    }
}