using System;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
namespace Searchers
{

    public class Searcher
    {

        public static bool isExist(string fileName)
        {
            string errorMessage= "The file: " + fileName + " could not be found!";

            if (!File.Exists(fileName))
            {
                Console.WriteLine(errorMessage);
                return false;
            }
            else
            {
                return true;
            }


        }
        public static int GetWordsCount(string file)
        {
            var result = file.Split(' ').ToList();
            return result.Count;

        }
        public static int GetSymbolsCount(string file)
        {
            var counter = 0;
            foreach (var symbols in file)
            {
                counter++;
            }
            return counter;
        }
        public static void Result(string fileName)
        {

            var readOnlyFile = File.ReadAllText(fileName);
            Console.WriteLine("===============================");
            Console.WriteLine(readOnlyFile);
            Console.WriteLine("===============================");
            Console.WriteLine("The file contains " + GetSymbolsCount(readOnlyFile) + " symbols");
            Console.WriteLine("The file contains ~ " + GetWordsCount(readOnlyFile) + " words");

            Console.WriteLine("Type a word to search");



            String searchInput = Console.ReadLine();
            while (searchInput != "!!exit")
            {
                String pattern = "\\b";
                pattern += searchInput;
                pattern += "\\b";
                int count = Regex.Matches(File.ReadAllText(fileName),
              pattern,
              RegexOptions.IgnoreCase).Count;
                // IgnoreCase = ignore case sens
                Console.WriteLine(" --- {0}  ===> {1}",searchInput,count);
                Console.WriteLine("Search a new word, or type !!exit");

                searchInput = Console.ReadLine();

            }

            // Do not forget to escape the pattern!

        }
        public static void Main()
        {
            // To search dinamically, just ask for a file:
            Console.WriteLine("Enter a file to search. Example: words.txt");

            String fileName = Console.ReadLine().Trim();

            if (isExist(fileName))
            {
                Result(fileName);
            }
            else
            {
                Console.WriteLine("Please enter a valid file name!");
                fileName = Console.ReadLine();
                if (isExist(fileName))
                {
                    Result(fileName);
                }
            }


        }
    }
}