using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TextFilter
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length < 3)
            {
                Console.WriteLine("Format:\r\nTextFilter.exe input.txt output.txt findWord1,findWord2");
                return;
            }

            string infile = args[0];
            string outfile = args[1];
            string[] find = args[2].Split(',');
            bool findOne = find.Length == 1;
            Console.WriteLine("In: " + infile);
            Console.WriteLine("Out: " + outfile);
            Console.WriteLine("Find: " + String.Join(",", find));

            if (!File.Exists(infile))
            {
                Console.WriteLine("Input file " + infile + " not exist!");
                return;
            }

            DateTime startTime = DateTime.Now;
            Console.WriteLine("Start time : " + startTime);
            int counter = 0;

            using (StreamWriter sw = new StreamWriter(outfile))
            {
                using (StreamReader sr = new StreamReader(infile))
                {
                    String line;
                    while ((line = sr.ReadLine()) != null)
                    {
                        if ((findOne && line.Contains(find[0])) || find.Any(x => line.Contains(x)))
                        {
                            if (++counter % 100 == 0)
                            {
                                sw.Flush();
                                Console.WriteLine(counter + " : " + line);
                            }
                            sw.WriteLine(line);
                        }
                    }
                }
            }

            Console.WriteLine("Done. Filtering time : " + (DateTime.Now - startTime));
            Console.ReadLine();
        }
    }
}