using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using Modbus.Device;      //for modbus master
using System.Net;         //for tcp client
using System.Net.Sockets;
using System.Threading;

namespace ReConnect
{
    class Program
    {
        [DllImport("WININET", CharSet = CharSet.Auto)]
        static extern bool InternetGetConnectedState(ref InternetConnectionState lpdwFlags, int dwReserved);
        enum InternetConnectionState : int
        {
            INTERNET_CONNECTION_MODEM = 0x1,
            INTERNET_CONNECTION_LAN = 0x2,
            INTERNET_CONNECTION_PROXY = 0x4,
            INTERNET_RAS_INSTALLED = 0x10,
            INTERNET_CONNECTION_OFFLINE = 0x20,
            INTERNET_CONNECTION_CONFIGURED = 0x40
        }

        private static TcpClient tcpClient;
        private static ModbusIpMaster master;
        
        static void Main(string[] args)
        {
            // connect to Modbus TCP Server
            bool NetworkIsOk = Connect();
            // read the input register 0~9 (30001~30010) of the device slave ID 1.
            //document->Modbus.Device.Namespace->ModbusMaster Class->ReadInputRegisters Method
            byte slaveID = 1;
            ushort startAddress = 0;
            ushort numOfPoints = 10;
            while (true)
            {
                try
                {
                    if (NetworkIsOk)
                    {
                        ushort[] register = master.ReadInputRegisters(slaveID, startAddress, numOfPoints);
                        for (int index = 0; index < register.Length; index++)
                            Console.WriteLine(string.Format("register[{0}] = {1}", index, register[index]));
                    }
                    else
                    {
                        NetworkIsOk = Connect();
                        Console.WriteLine("Network:" + NetworkIsOk.ToString());
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                    Thread.Sleep(10000);
                    NetworkIsOk = false;
                }
                Thread.Sleep(1000);
            }
        }

        private static bool Connect()
        {
            string ipAddress = "192.168.1.100";
            int tcpPort = 502;
            if (master != null)
                master.Dispose();
            if (tcpClient != null)
                tcpClient.Close();

            if (CheckInternet())
            {
                try
                {
                    tcpClient = new TcpClient(ipAddress, tcpPort);

                    // create Modbus TCP Master by the tcp client
                    //document->Modbus.Device.Namespace->ModbusIpMaster Class->Create Method
                    master = ModbusIpMaster.CreateIp(tcpClient);
                    return true;
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.StackTrace + "==>" + ex.Message);
                    return false;
                }
            }
            return false;

        }
        private static bool CheckInternet()
        {
            //http://msdn.microsoft.com/en-us/library/windows/desktop/aa384702(v=vs.85).aspx
            InternetConnectionState flag = InternetConnectionState.INTERNET_CONNECTION_LAN;
            return InternetGetConnectedState(ref flag, 0);
        }
    }
}