using System;
using System.ComponentModel;
using System.Runtime.InteropServices;

namespace UncRock
{
    public static class Permissions
    {
        [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool LookupPrivilegeValue(string lpsystemname, string lpname, [MarshalAs(UnmanagedType.Struct)] ref Luid lpLuid);

        [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool AdjustTokenPrivileges(IntPtr tokenhandle, [MarshalAs(UnmanagedType.Bool)] bool disableAllPrivileges, [MarshalAs(UnmanagedType.Struct)] ref TokenPrivledges newstate, uint bufferlength, IntPtr previousState, IntPtr returnlength);

        internal const int SePrivledgeEnabled = 0x00000002;
        internal const int ErrorNotAllAssigned = 1300;
        internal const UInt32 TokenQuery = 0x0008;
        internal const UInt32 TokenAdjustPrivledges = 0x0020;

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        internal static extern IntPtr GetCurrentProcess();

        [DllImport("Advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool OpenProcessToken(IntPtr processHandle, uint desiredAccesss, out IntPtr tokenHandle);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern Boolean CloseHandle(IntPtr hObject);

        [StructLayout(LayoutKind.Sequential)]
        internal struct Luid
        {
            internal Int32 LowPart;
            internal UInt32 HighPart;
        }

        [StructLayout(LayoutKind.Sequential)]
        internal struct TokenPrivledges
        {
            internal Int32 PrivilegeCount;
            internal Luid Luid;
            internal Int32 Attributes;
        }
        public static void EnablePrivilege(string securityEntity)
        {

            string securityEntityValue = securityEntity;
            try
            {
                Luid locallyUniqueIdentifier = new Luid();

                if (LookupPrivilegeValue(null, securityEntityValue, ref locallyUniqueIdentifier))
                {
                    TokenPrivledges tokenPrivledges = new TokenPrivledges();
                    tokenPrivledges.PrivilegeCount = 1;
                    tokenPrivledges.Attributes = SePrivledgeEnabled;
                    tokenPrivledges.Luid = locallyUniqueIdentifier;

                    IntPtr tokenHandle = IntPtr.Zero;
                    try
                    {
                        IntPtr currentProcess = GetCurrentProcess();
                        if (OpenProcessToken(currentProcess, TokenAdjustPrivledges | TokenQuery, out tokenHandle))
                        {
                            if (AdjustTokenPrivileges(tokenHandle, false, ref tokenPrivledges, 1024, IntPtr.Zero, IntPtr.Zero))
                            {
                                Int32 lastError = Marshal.GetLastWin32Error();
                                if (lastError == ErrorNotAllAssigned)
                                {
                                    Win32Exception win32Exception = new Win32Exception();
                                    throw new InvalidOperationException("AdjustTokenPrivileges fail.", win32Exception);
                                }
                            }
                            else
                            {
                                Win32Exception win32Exception = new Win32Exception();
                                throw new InvalidOperationException("AdjustTokenPrivileges fail.", win32Exception);
                            }
                        }
                        else
                        {
                            Win32Exception win32Exception = new Win32Exception();

                            string exceptionMessage = "OpenProcessToken fail. Process: " + currentProcess.ToInt32().ToString();

                            throw new InvalidOperationException(exceptionMessage, win32Exception);
                        }
                    }
                    finally
                    {
                        if (tokenHandle != IntPtr.Zero)
                            CloseHandle(tokenHandle);
                    }
                }
                else
                {
                    Win32Exception win32Exception = new Win32Exception();

                    string exceptionMessage = "LookupPrivilegeValue failed. SecurityEntityValue: " + securityEntityValue.ToString();

                    throw new InvalidOperationException(exceptionMessage, win32Exception);
                }
            }
            catch (Exception e)
            {
                string exceptionMessage = "GrandPrivilege failed. SecurityEntity: " + securityEntityValue.ToString();

                throw new InvalidOperationException(exceptionMessage, e);
            }
        }


    }
}