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

namespace TextAnalysis
{
    static class SentencesParserTask
    {
        static char[] separatorCharacters = new char[] {'.', '!', '?', ';', ':', '(', ')'};

        public static List<List<string>> ParseSentences(string text)
        {
            var sentencesList = new List<List<string>>();
            string[] workText = GetWorkingText(ref text);
            foreach (var word in workText)
            {
                if (word != "")
                {
                    word.Trim();
                    var list = findOutWordList(word + " ");
                    if (list != null)
                        sentencesList.Add(list);
                }

            }
            Console.WriteLine(string.Join(", ", sentencesList));
            return sentencesList;
        }
        private static string[] GetWorkingText(ref string text)
        {
            text = text.ToLower();
            var workText = @text.Split(separatorCharacters);
            return workText;
        }

        private static List<string> findOutWordList(string word)
        {
            var wordList = new List<string>();
            var strBuilder = new StringBuilder();
            foreach (var symbol in word)
            {
                if (char.IsLetter(symbol) || symbol == '\'')
                {
                    strBuilder.Append(symbol);
                }
                else
                {
                    var finWord = strBuilder.ToString();
                    finWord.Trim();
                    if (finWord != "")
                    {
                        wordList.Add(finWord);
                        strBuilder = new StringBuilder();
                    }
                }
            }
            return wordList;
        }
    }
}