using System;
using System.Collections.Generic;
using System.Net.Sockets;
using System.Threading;
using System.Net;
using System.Diagnostics;

namespace TCPServerService
{
    class RegistrationThread
    {
        int port;
        private Socket socket;
        private List<ReadThread> allThreads = new List<ReadThread>();

        public bool checkForPings = true;

        public RegistrationThread(int registrationPort)
        {
            port = registrationPort;           
        }

        public void handleConnection()
        {
            Utils.WriteEventLog(Program.COMPANY, "Registration Thread - Initialized on Port " + port, EventLogEntryType.Information, 34500); 
            TcpListener myListener = new TcpListener(IPAddress.Any, port);
            myListener.Start();
            int count = 0;
            while (true)
            {
                try
                {
                    socket = myListener.AcceptSocket();                    
                    String clientIP = ((IPEndPoint)socket.RemoteEndPoint).Address.ToString();

                    Utils.WriteEventLog(Program.COMPANY, "IP " + clientIP + " connected", EventLogEntryType.Information, 34500);                     
                    Service1.listOFSocket.Add(socket);
                    Utils.WriteEventLog(Program.COMPANY, "Total connections: " + Service1.listOFSocket.Count, EventLogEntryType.Information, 34500);
                    //Service1.writeToFile(string.Format("Total connections: {0} {1}", Service1.listOFSocket.Count.ToString(), DateTime.Now.ToString()));
                    ReadThread RegistrationConnection = new ReadThread(socket);
                    RegistrationConnection.OnReadException += RegistrationConnection_OnReadException;
                    Thread LocationThreadObj = new Thread(new ThreadStart(RegistrationConnection.handleConnection));
                    LocationThreadObj.IsBackground = true;
                    LocationThreadObj.Start();
                    allThreads.Add(RegistrationConnection);
                }
                catch (Exception e)
                {
                    Utils.WriteEventLog(Program.COMPANY, "Ex in appserver:Registration thread: " + e.ToString(), EventLogEntryType.Error, 23456);
                    //Form1.appDead = true;
                }
                Thread.Sleep(1);


                if (count++ > 5000)
                {

                    RemoveClient(null);

                    count = 0;

                }
            }
            //myListener.Stop();
        }

        private void RegistrationConnection_OnReadException(string clientIP)
        {
            RemoveClient(clientIP);
        }

        private Object _lock = new Object();

        private void RemoveClient(String clientIP)
        {
            lock (_lock)
            {
                try
                {
                    // create list to store the threads that needs to be removed 
                    List<ReadThread> toRemove = new List<ReadThread>();

                    // iterate all active threads to search for lost pings
                    foreach (ReadThread thread in allThreads)
                    {
                        bool pingExpired = checkForPings && (ReadThread.PING_INTERVAL_SEC * 3) < (DateTime.Now - thread.lastPingTime).TotalSeconds;

                        //Utils.WriteEventLog(Program.COMPANY, "PING: " + thread.lastPingTime.ToShortDateString() + " | | | " 
                        //    + (DateTime.Now - thread.lastPingTime).TotalSeconds, EventLogEntryType.SuccessAudit, 23456);

                        // if 3 pings were lost 
                        if (pingExpired || (clientIP != null && thread.clientIP.Equals(clientIP)))
                        {
                            try
                            {
                                Utils.WriteEventLog(Program.COMPANY, $"Closing socket with {thread.clientIP} {(pingExpired ? "due to lost PINGS" : "closed socket")}", EventLogEntryType.Warning, 23456);
                                // close connection, remove it and then flag it as to be removed
                                thread.socket.Close();
                                Service1.listOFSocket.Remove(thread.socket);
                                toRemove.Add(thread);
                            }
                            catch (Exception ex)
                            {
                                Utils.WriteEventLog(Program.COMPANY, "Unable to close socket: " + ex.ToString(), EventLogEntryType.Error, 23456);
                            }
                        }
                    }

                    // remove all threads that are closed due to inactive ping
                    foreach (ReadThread thread in toRemove)
                    {
                        thread.isRunning = false;
                        allThreads.Remove(thread);
                    }
                }
                catch(Exception ex)
                {
                    Utils.WriteEventLog(Program.COMPANY, "Error removing client : " + ex.ToString(), EventLogEntryType.Error, 23456);
                }
            }
        }


        public void onUdpSendingFailed(String clientIP)
        {
            RemoveClient(clientIP);
        }
    }
}