using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.Windows.Forms;

namespace NetOpenVpnGui
{
    class Runner
    {
        private UdpClient net_send;
        private IPEndPoint net_send_port;
        private UdpClient net_gets;
        private IPEndPoint net_gets_port;
        private string messageReceivedString;
        private bool messageReceived;
        private bool net_init = false;
        public Runner(String p)
        {
            this.service = p;
        }

        public bool run_service()
        {
            return this.send("service start " + this.service);
        }

        public bool stop_service()
        {
            return this.send("service stop " + this.service);
        }

        public bool check_service()
        {
            return this.send("service status " + this.service);
        }

        private bool send(string p)
        {
            this.init();
            byte[] data = Encoding.UTF8.GetBytes(p);
            this.net_send.Send(data, data.Length, this.net_send_port);
            //net_gets.Receive(ref net_gets_port);

            UdpState s = new UdpState();
            s.e = net_gets_port;
            s.u = net_gets;
            this.messageReceived = false;
            net_gets.BeginReceive(new AsyncCallback(ReceiveCallback), s);
            int i=0;
            while (!this.messageReceived && i++<100)
            {
                System.Threading.Thread.Sleep(100);
            }
            if (!this.messageReceived)
            {
                this.close();
                return false;
            }
            this.close();
            return Boolean.Parse(this.messageReceivedString);

        }

        private void close()
        {
            if (this.net_init)
            {
                this.net_init = false;
                this.net_gets.Close();
                this.net_send.Close();
            }
        }

        private void init()
        {
            if (!this.net_init)
            {
                this.net_init = true;
                this.net_send = new UdpClient();
                this.net_gets = new UdpClient(34524);
                this.net_send_port = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 34523);
                this.net_gets_port = new IPEndPoint(IPAddress.Loopback, 0);
            }
        }



        private void ReceiveCallback(IAsyncResult ar)
        {
            UdpClient u = (UdpClient)((UdpState)(ar.AsyncState)).u;
            IPEndPoint e = (IPEndPoint)((UdpState)(ar.AsyncState)).e;
            try
            {
                Byte[] receiveBytes = u.EndReceive(ar, ref e);
                this.messageReceivedString = Encoding.UTF8.GetString(receiveBytes);
                this.messageReceived = true;
            }
            catch (Exception)
            {
                this.messageReceivedString = "";
                this.messageReceived = false;
            }
            
        }


        public string service { get; set; }
    }

    public class UdpState
    {
        public IPEndPoint e;
        public UdpClient u;
    }
}