using System;
using System.Diagnostics;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;

namespace MelonVPNCore
{
    public static class DaemonSocketServer
    {
        public static void StartServer()
        {
            IPHostEntry host = Dns.GetHostEntry("localhost");
            IPAddress ipAddress = host.AddressList[0];
            IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 22035);

            try
            {
                Socket listener = new Socket(ipAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
                listener.Bind(localEndPoint);
                listener.Listen(10);

                Process currentVpnProcess = null;
                string lastClientUpdate = Messages.EOF;

                while (true)
                {
                    Socket handler = listener.Accept();

                    string data = null;
                    byte[] bytes = null;

                    while (true)
                    {
                        bytes = new byte[1024];
                        int bytesRec = handler.Receive(bytes);
                        data += Encoding.ASCII.GetString(bytes, 0, bytesRec);
                        if (data.IndexOf(Messages.EOF, StringComparison.CurrentCulture) > -1) break;
                    }

                    if (data.StartsWith(Messages.ClientListStartMsg, StringComparison.CurrentCulture))
                    {
                        lastClientUpdate = data;
                        Client.SendCustomMessage(lastClientUpdate, true);
                    }
                    else if (data == Messages.StatusMsg)
                    {
                        Console.WriteLine("Status requested");
                        if (currentVpnProcess != null && !currentVpnProcess.HasExited)
                        {
                            Console.WriteLine("Sending response: online");
                            Client.SendDataMessage(DataMessage.Online, true);
                            Client.SendCustomMessage(lastClientUpdate, true);
                        }
                        else
                        {
                            Console.WriteLine("Sending response: offline");
                            Client.SendDataMessage(DataMessage.Offline, true);
                            Client.SendCustomMessage(Messages.ClientListEmptyMsg, true);
                        }
                    }
                    else if (data == Messages.StartMsg)
                    {
                        if (currentVpnProcess == null)
                        {
                            Console.WriteLine("Starting VPN");
                            try
                            {
                                Console.WriteLine("Starting embedded process");
                                currentVpnProcess = new Process
                                {
                                    StartInfo = new ProcessStartInfo("simple-vpn", "client /etc/melon-vpn/client.cfg")
                                };
                                currentVpnProcess.Exited += delegate
                                  {
                                      Client.SendDataMessage(DataMessage.Offline, true);
                                      currentVpnProcess = null;
                                  };
                                currentVpnProcess.Start();
                                Console.WriteLine("Sending online reply");
                                Thread.Sleep(1500);
                                Client.SendDataMessage(DataMessage.Online, true);
                            }
                            catch (Exception e)
                            {
                                Console.WriteLine("There was an error. But I fixed it.");
                                Console.WriteLine("It looked like this: " + e);
                                currentVpnProcess = null;
                                Client.SendDataMessage(DataMessage.Error, true);
                                Client.SendCustomMessage(Messages.ClientListEmptyMsg, true);
                            }
                        }
                        else
                        {
                            Console.WriteLine("VPN already started");
                        }
                    }
                    else if (data == Messages.StopMsg)
                    {
                        if (currentVpnProcess != null)
                        {
                            Console.WriteLine("Stopping VPN");
                            try
                            {
                                Console.WriteLine("Stopping embedded process");
                                currentVpnProcess.Kill();
                                currentVpnProcess = null;
                                Console.WriteLine("Sending offline reply");
                                Client.SendDataMessage(DataMessage.Offline, true);
                                Client.SendCustomMessage(Messages.ClientListEmptyMsg, true);
                            }
                            catch (Exception e)
                            {
                                Console.WriteLine("There was an error. But I fixed it.");
                                Console.WriteLine("It looked like this: " + e);
                                currentVpnProcess = null;
                                Client.SendDataMessage(DataMessage.Error, true);
                                Client.SendCustomMessage(Messages.ClientListEmptyMsg, true);
                            }
                        }
                        else
                        {
                            Console.WriteLine("VPN already stopped");
                        }
                    }

                    Client.SendDataMessage(DataMessage.Blank, true);

                    handler.Shutdown(SocketShutdown.Both);
                    handler.Close();
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }
        }
    }
}