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

namespace TableParser
{
    public class FieldsParserTask
    {
        public static List<string> ParseLine(string line)
        {
            if (line.Length == 0)
                return new List<string> { };
            else if (!line.Contains("\"") && !line.Contains("'"))
                return line.Trim().Split(' ').ToList();
            else
            {
                var fields = new List<string>();
                var i = 0;
                while (i < (line.Trim()).Length)
                {
                    var field = ReadField(line.Trim(), i);
                    fields.Add(field.Value);
                    i += field.Length;
                }
                return fields;
            }
        }

        public static Token QuotesOrNotQuotes(string line, int startIndex, char closeChar)
        {
            var str = "";
            var backslash = 0;
            var newStartIndex = startIndex + 1; //чтобы кавычки не вошли в поле
            while (newStartIndex < line.Length && line[newStartIndex] != closeChar)
            {
                //ищем слеши
                if (line[newStartIndex] == '\\')
                {
                    backslash++;
                    newStartIndex++; //т к \\ = \
                }
                str = str + line[newStartIndex];
                newStartIndex++;
            }
            return new Token(str, startIndex, str.Length + backslash + 2); //т к мы вручную убирали кавычки
        }

        public static Token QuotesOrNotQuotesInside(string line, int startIndex)
        {
            var str = "";
            var backslash = 0;
			var index = startIndex;
            var closeChars = "\'\"".ToCharArray();
            while (index < line.Length && !closeChars.Contains(line[index]))
            {
                if (line[startIndex] == '\\')
                {
                    backslash++;
                    index++;
                }
                str = str + line[index];
                index++;
            }
            return new Token(str, index, str.Length + backslash);
        }

        private static Token ReadField(string line, int startIndex)
        {
            if (line[startIndex] == '\"')
                return QuotesOrNotQuotes(line, startIndex, '\"');
            else if (line[startIndex] == '\'')
                return QuotesOrNotQuotes(line, startIndex, '\'');
            else
                return QuotesOrNotQuotesInside(line, startIndex);
        }
    }
}