using System;
using System.Collections.Generic;
using System.IO;
using System.Xml.Linq;
using System.Linq;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace mirror
{

   class Ftp
   {
       public String server;
       private int port;

       private TcpClient client;
       private NetworkStream stream;

       public Ftp(String server, int port)
       {
           this.server = server;
           this.port = port;
       }

       public void Connect()
       {
           client = new TcpClient();
           client.Connect(this.server, this.port);
           stream = client.GetStream();

           byte[] buffer = new byte[1024];
           int bytes = stream.Read(buffer, 0, buffer.Length);

           String response = Encoding.ASCII.GetString(buffer, 0, bytes);
           int responseState = Convert.ToInt32(response.Substring(0, 3));


       }

       public String SendText(String message, int responseExpected)
       {
           byte[] text = Encoding.ASCII.GetBytes(message);
           stream.Write(text, 0, text.Length);

           byte[] buffer = new byte[1024];
           int bytes = stream.Read(buffer, 0, buffer.Length);
           String response = Encoding.ASCII.GetString(buffer, 0, bytes);

           int responseState = -1;
           if (response != null)
           {
               responseState = Convert.ToInt32(response.Substring(0, 3));
           }

           return response;
       }

       public int CountPort(String serverResponse)
       {
           String response = serverResponse.Substring(serverResponse.IndexOf("(") + 1);
           response = response.Remove(response.Length - 4);
           String[] nums = response.Split(',');
           int first = Int32.Parse(nums[nums.Length - 2]);
           int second = Int32.Parse(nums[nums.Length - 1]);

           return (first * 256 + second);
       }

       public void Disconnect()
       {
           SendText("QUIT\r\n", 221);
           stream.Close();
           client.Close();
       }

       public void Receive()
       {
           byte[] buffer = new byte[1024];
           int bytes = stream.Read(buffer, 0, buffer.Length);
           String response = Encoding.ASCII.GetString(buffer, 0, bytes);

           //Console.WriteLine("Odpowiedz serwera:\n" + response);
       }

       public String List()
       {
           this.SendText("TYPE A\r\n", 200);

           String passiveModeResponse = this.SendText("PASV\r\n", 227);

           int downloadPort = this.CountPort(passiveModeResponse);

           FtpData ftpDataConnection = new FtpData();
           ftpDataConnection.Connect(server, downloadPort);

           this.SendText("LIST\r\n", 150);

           String list = ftpDataConnection.ReceiveText(225);
           ftpDataConnection.Disconnect();

           this.Receive();

           this.SendText("TYPE I\r\n", 200);

           return list;
       }


       public void SetWriteTime(String filename, String localDirectory)
       {
           String passiveModeResponse = this.SendText("PASV\r\n", 227);
           int newPort = this.CountPort(passiveModeResponse);

           FtpData ftpDataConnection = new FtpData();
           ftpDataConnection.Connect(server, newPort);

           //pobranie daty modyfikacji
           String mdtm = this.SendText("MDTM " + filename + "\r\n", 213);

           ftpDataConnection.Disconnect();

           int year = Int32.Parse(mdtm.Substring(4, 4));
           int month = Int32.Parse(mdtm.Substring(8, 2));
           int day = Int32.Parse(mdtm.Substring(10, 2));
           int hours = Int32.Parse(mdtm.Substring(12, 2));
           int minutes = Int32.Parse(mdtm.Substring(14, 2));
           int seconds = Int32.Parse(mdtm.Substring(16, 2));

           File.SetLastWriteTime(localDirectory + "/" + filename, new DateTime(year, month, day, hours, minutes, seconds));
       }
    }

   class FtpData
   {
       private TcpClient client;
       private NetworkStream stream;

       public void Connect(String server, int port)
       {
           client = new TcpClient();
           client.Connect(server, port);
           stream = client.GetStream();
       }

       public void Disconnect()
       {
           byte[] text = Encoding.ASCII.GetBytes("QUIT\r\n");
           stream.Write(text, 0, text.Length);
           stream.Close();
           client.Close();
       }

       public String ReceiveText(int expectedResponse)
       {
           byte[] buffer = new byte[900000];
           String response = "";
           int bytesRead = 0;

           do
           {
               bytesRead = stream.Read(buffer, 0, buffer.Length);
               response += Encoding.ASCII.GetString(buffer, 0, bytesRead);
           }
           while (stream.DataAvailable);

           if ((response != "") && (response.Substring(0, 3) == expectedResponse.ToString()))
           {
               Console.WriteLine("Blad! Jedno polaczenie danych jest juz otwarte!\n");
               Console.WriteLine("Odpowiedz serwera:\n" + response);
               this.Disconnect();
               Console.ReadLine();
               Environment.Exit(0);
           }
           if (response != "")
           {
               response = response.Remove(response.Length - 1);
               Console.WriteLine(response);
           }
           return response;
       }

   }


   class Program
    {
        static void Main(string[] args)
        {
            XDocument xdoc = XDocument.Load("app.xml");
            String server = xdoc.Descendants("server").First().Value;
            String user = xdoc.Descendants("user").First().Value;
            String serverDirectory = xdoc.Descendants("serverDirectory").First().Value;
            String localDirectory = xdoc.Descendants("localDirectory").First().Value;
            int port;

            try
            {
                server = args[0].Substring(args[0].IndexOf('@') + 1, args[0].IndexOf("/") - args[0].IndexOf('@') - 1);
                port = 21;
                user = args[0].Substring(0, args[0].IndexOf('@'));
                serverDirectory = args[0].Substring(args[0].IndexOf('/') + 1);
                localDirectory = args[1];
                Console.WriteLine();
            }
            catch (Exception e)
            {
                Console.WriteLine("Blad! Niepoprawne argumenty.");
                Console.Write(e.ToString());
                return;
            }

            int maxLevel = -1;
            if (args.Length == 3)
            {
                maxLevel = Int32.Parse(args[2].Substring(1, args[2].Length - 1));
            }

            //połączenie kontrolne
            Ftp ftp = new Ftp(server, port);
            ftp.Connect();
            Console.WriteLine("Połączono");
            //autentykacja
            ftp.SendText("USER " + user + "\r\n", 331);
            Console.WriteLine("Prosze wprowadzic haslo:");
            String password = ReadPassword();
            Console.WriteLine("\n");
            ftp.SendText("PASS " + new String('*', password.Length) + "\r\n", 230);

            //przejście do interesującego nas katalogu
            ftp.SendText("CWD " + serverDirectory + "\r\n", 250);

            //utworzenie lokalnego katalogu (jeśli nie istnieje)
            if (!Directory.Exists(localDirectory))
            {
                Directory.CreateDirectory(localDirectory);
            }

            //tryb tekstowy
            ftp.SendText("TYPE A\r\n", 200);

            String passiveModeResponse = ftp.SendText("PASV\r\n", 227);

            int downloadPort = ftp.CountPort(passiveModeResponse);

            //połączenie danych
            FtpData ftpDataConnection = new FtpData();
            ftpDataConnection.Connect(ftp.server, downloadPort);

            ftp.SendText("LIST\r\n", 150);

            //odbieranie listy
            String list = ftpDataConnection.ReceiveText(225);
            //zamknięcie połączenia danych
            ftpDataConnection.Disconnect();

            //info czy transfer zakończył się sukcesem
            ftp.Receive();

            //tryb binarny (odbiór plików)
            ftp.SendText("TYPE I\r\n", 200);

            String[] elements = list.Split('\n');
            String[] info;

            foreach(String element in elements)
            {
                info = element.Split(' ');

                //jeśli element jest plikiem
                if (info.Length >= 20 && element.ElementAt(0) == '-')
                {
                    String filename = info[info.Length - 1].Remove(info[info.Length - 1].Length - 1);
                    //jeśli plik nie istnieje w katalogu lokalnym to go pobieramy
                    if (!File.Exists(localDirectory + "/" + filename))
                    {
                    }
                    else //jeśli istnieje to porównujemy daty modyfikacji
                    {
                        String mdtm = ftp.SendText("MDTM " + filename + "\r\n", 213);
                        int year = Int32.Parse(mdtm.Substring(4, 4));
                        int month = Int32.Parse(mdtm.Substring(8, 2));
                        int day = Int32.Parse(mdtm.Substring(10, 2));
                        int hours = Int32.Parse(mdtm.Substring(12, 2));
                        int minutes = Int32.Parse(mdtm.Substring(14, 2));
                        int seconds = Int32.Parse(mdtm.Substring(16, 2));

                        DateTime newTime = new DateTime(year, month, day, hours, minutes, seconds);
                        DateTime oldTime = File.GetLastWriteTime(localDirectory + "/" + filename);


                    }
                }
                else if (info.Length >= 20 && element.ElementAt(0) == 'd') //jeśli element jest katalogiem
                {
                    String directoryName = info[info.Length - 1].Remove(info[info.Length - 1].Length - 1);

                    if (!Directory.Exists(localDirectory + "/" + directoryName))
                    {
                        Directory.CreateDirectory(localDirectory + "/" + directoryName);
                    }
                    if (maxLevel != 0) // limit nieustawiony lub 0 to pobieramy zawartość
                    {
                        String serverDirectoryPath = serverDirectory + directoryName;
                        ftp.SendText("CWD " + directoryName + "/\r\n", 250);
                        ftp.SendText("CDUP\r\n", 250);
                    }

                }
            }

            ftp.Disconnect();

            Console.ReadLine();
        }

       public static String ReadPassword()
       {
           String password = "";
           char key;

           while ((key = Console.ReadKey(true).KeyChar) != '\r')
           {
               if (key == '\b' && password.Length > 0)
               {
                   Console.Write("\b \b");
                   password = password.Remove(password.Length - 1, 1);
               }
               else if (Char.IsLetterOrDigit(key))
               {
                   Console.Write("*");
                   password = password + key;
               }
           }

           return password;
       }
    }
}