namespace Tools;

using System.IO;
using System.Runtime.InteropServices;

/// <summary>
/// Wrapper for the "NET USE" functionality.
/// Connect to a network resource, e.g. a network share under a different user.
/// </summary>
/// <remarks>
/// Encapsulate an instance into a using-directive like e.g.:
/// ...
/// using ( new NetworkConnection( @"\\myshare", true, "myUsername", "myPassword" ) )
/// {
///     ...
///     [code that connects to the network share under the new user context]
///     ...
/// }
/// ...
/// </remarks>
[PublicAPI]
public sealed class NetworkConnection : IDisposable
{
	private string? _networkName;

	public NetworkConnection(
		string networkName,
		bool activate,
		string userName,
		string password)
	{
		if (activate)
		{
			doNetUse(networkName, userName, password);
		}
	}

	private void doNetUse(string networkName, string userName, string password)
	{
		var netResource = new NetResource
		{
			Scope = ResourceScope.GlobalNetwork,
			ResourceType = ResourceType.Disk,
			DisplayType = ResourceDisplaytype.Share,
			RemoteName = networkName
		};

		var result = WNetAddConnection2(
			netResource,
			password,
			userName,
			0);

		if (result != 0)
		{
			throw new IOException($"Error connecting to remote share '{networkName}': {result}", result);
		}

		_networkName = networkName;
	}

	~NetworkConnection()
	{
		doDispose();
	}

	public void Dispose()
	{
		doDispose();
		GC.SuppressFinalize(this);
	}

	private void doDispose()
	{
		if (!string.IsNullOrEmpty(_networkName))
		{
			var nn = _networkName;
			_networkName = null;
			var result = WNetCancelConnection2(nn, 0, true);
			Trace.TraceInformation("Result for canceling network connection: {0}.", result);
		}
	}

	[DllImport(@"mpr.dll", CharSet = CharSet.Unicode)]
	private static extern int WNetAddConnection2(
		NetResource netResource,
		string password,
		string username,
		int flags);

	[DllImport(@"mpr.dll", CharSet = CharSet.Unicode)]
	private static extern int WNetCancelConnection2(
		string? name,
		int flags,
		bool force);
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public class NetResource
{
	// ReSharper disable NotAccessedField.Global
	// ReSharper disable NotAccessedField.Global
	// ReSharper disable UnusedMember.Global
	public ResourceScope Scope;
	public ResourceType ResourceType;
	public ResourceDisplaytype DisplayType;
	public int Usage;
	public string? LocalName;
	public string? RemoteName;
	public string? Comment;
	public string? Provider;
	// ReSharper restore UnusedMember.Global
	// ReSharper restore NotAccessedField.Global
	// ReSharper restore UnusedMember.Global
}

public enum ResourceScope
{
	// ReSharper disable NotAccessedField.Global
	// ReSharper disable UnusedMember.Global
	Connected = 1,
	GlobalNetwork,
	Remembered,
	Recent,
	Context
	// ReSharper restore UnusedMember.Global
	// ReSharper restore UnusedMember.Global
};

public enum ResourceType
{
	// ReSharper disable UnusedMember.Global
	// ReSharper disable UnusedMember.Global
	Any = 0,
	Disk = 1,
	Print = 2,
	Reserved = 8,
	// ReSharper restore UnusedMember.Global
	// ReSharper restore UnusedMember.Global
}

public enum ResourceDisplaytype
{
	// ReSharper disable UnusedMember.Global
	// ReSharper disable UnusedMember.Global
	Generic = 0x0,
	Domain = 0x01,
	Server = 0x02,
	Share = 0x03,
	File = 0x04,
	Group = 0x05,
	Network = 0x06,
	Root = 0x07,
	Shareadmin = 0x08,
	Directory = 0x09,
	Tree = 0x0a,
	Ndscontainer = 0x0b
	// ReSharper restore UnusedMember.Global
	// ReSharper restore UnusedMember.Global
}