using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Net.NetworkInformation;

using System.Runtime.InteropServices;

using System.Runtime.InteropServices.ComTypes;

using System.Diagnostics;

using NETWORKLIST;

namespace SharpDisplayManager

{

	public class NetworkManager: INetworkListManagerEvents, IDisposable

    {

		public delegate void OnConnectivityChangedDelegate(NetworkManager aNetworkManager, NLM_CONNECTIVITY aConnectivity);

		public event OnConnectivityChangedDelegate OnConnectivityChanged;

		private int iCookie = 0;

        private IConnectionPoint iConnectionPoint;

        private INetworkListManager iNetworkListManager;

		public NetworkManager()

		{

			iNetworkListManager = new NetworkListManager();

			ConnectToNetworkListManagerEvents();

		}

		public void Dispose()

		{

			//Not sure why this is not working form here

			//Possibly because something is doing automatically before we get there

			//DisconnectFromNetworkListManagerEvents();

		}

		public INetworkListManager NetworkListManager

		{

			get { return iNetworkListManager; }

		}

		public void ConnectivityChanged(NLM_CONNECTIVITY newConnectivity)

		{

			//Fire our event

			OnConnectivityChanged(this, newConnectivity);

		}

		public void ConnectToNetworkListManagerEvents()

		{

			Debug.WriteLine("Subscribing to INetworkListManagerEvents");

			IConnectionPointContainer icpc = (IConnectionPointContainer)iNetworkListManager;

			//similar event subscription can be used for INetworkEvents and INetworkConnectionEvents

			Guid tempGuid = typeof(INetworkListManagerEvents).GUID;

			icpc.FindConnectionPoint(ref tempGuid, out iConnectionPoint);

			iConnectionPoint.Advise(this, out iCookie);

		}

		public void DisconnectFromNetworkListManagerEvents()

		{

			Debug.WriteLine("Un-subscribing to INetworkListManagerEvents");

			iConnectionPoint.Unadvise(iCookie);

		} 

		/// <summary>

		/// Indicates whether any network connection is available

		/// Filter connections below a specified speed, as well as virtual network cards.

		/// </summary>

		/// <returns>

		///     <c>true</c> if a network connection is available; otherwise, <c>false</c>.

		/// </returns>

		public static bool IsAvailable()

		{

			return IsAvailable(0);

		}

		/// <summary>

		/// Indicates whether any network connection is available.

		/// Filter connections below a specified speed, as well as virtual network cards.

		/// </summary>

		/// <param name="minimumSpeed">The minimum speed required. Passing 0 will not filter connection using speed.</param>

		/// <returns>

		///     <c>true</c> if a network connection is available; otherwise, <c>false</c>.

		/// </returns>

		public static bool IsAvailable(long minimumSpeed)

		{

			if (!NetworkInterface.GetIsNetworkAvailable())

				return false;

			foreach (NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces())

			{

				// discard because of standard reasons

				if ((ni.OperationalStatus != OperationalStatus.Up) ||

					(ni.NetworkInterfaceType == NetworkInterfaceType.Loopback) ||

					(ni.NetworkInterfaceType == NetworkInterfaceType.Tunnel))

					continue;

				// this allow to filter modems, serial, etc.

				// I use 10000000 as a minimum speed for most cases

				if (ni.Speed < minimumSpeed)

					continue;

				// discard virtual cards (virtual box, virtual pc, etc.)

				if ((ni.Description.IndexOf("virtual", StringComparison.OrdinalIgnoreCase) >= 0) ||

					(ni.Name.IndexOf("virtual", StringComparison.OrdinalIgnoreCase) >= 0))

					continue;

				// discard "Microsoft Loopback Adapter", it will not show as NetworkInterfaceType.Loopback but as Ethernet Card.

				if (ni.Description.Equals("Microsoft Loopback Adapter", StringComparison.OrdinalIgnoreCase))

					continue;

				return true;

			}

			return false;

		}

		/// <summary>

		/// 

		/// </summary>

		/// <returns></returns>

		public static bool HasInternet()

		{

			return false;

			//ConnectionProfile connections = NetworkInformation.GetInternetConnectionProfile();

			//bool internet = connections != null && connections.GetNetworkConnectivityLevel() == NetworkConnectivityLevel.InternetAccess;

			//return internet;

		}

	}

}