using System;
using System.Runtime.InteropServices;
using System.Text;

namespace Read64bitRegistryFrom32bitApp
{
	public enum RegSAM
	{
		QueryValue = 0x0001,
		SetValue = 0x0002,
		CreateSubKey = 0x0004,
		EnumerateSubKeys = 0x0008,
		Notify = 0x0010,
		CreateLink = 0x0020,
		WOW64_32Key = 0x0200,
		WOW64_64Key = 0x0100,
		WOW64_Res = 0x0300,
		Read = 0x00020019,
		Write = 0x00020006,
		Execute = 0x00020019,
		AllAccess = 0x000f003f
	}

	public static class RegHive
	{
		public static UIntPtr HKEY_LOCAL_MACHINE = new UIntPtr(0x80000002u);
		public static UIntPtr HKEY_CURRENT_USER = new UIntPtr(0x80000001u);
	}

	public static class RegistryWOW6432
	{
		#region Member Variables
		#region Read 64bit Reg from 32bit app
		[DllImport("Advapi32.dll")]
		static extern uint RegOpenKeyEx(
				UIntPtr hKey,
				string lpSubKey,
				uint ulOptions,
				int samDesired,
				out int phkResult);

		[DllImport("Advapi32.dll")]
		static extern uint RegCloseKey(int hKey);

		[DllImport("advapi32.dll", EntryPoint = "RegQueryValueEx")]
		public static extern int RegQueryValueEx(
				int hKey, string lpValueName,
				int lpReserved,
				ref uint lpType,
				System.Text.StringBuilder lpData,
				ref uint lpcbData);
		#endregion
		#endregion

		#region Functions
		static public string GetRegKey64Value(UIntPtr inHive, String inKeyName, String inPropertyName)
		{
			return GetRegKey64Value(inHive, inKeyName, RegSAM.WOW64_64Key, inPropertyName);
		}
		static public string GetRegKey32Value(UIntPtr inHive, String inKeyName, String inPropertyName)
		{
			return GetRegKey64Value(inHive, inKeyName, RegSAM.WOW64_32Key, inPropertyName);
		}
		static public string GetRegKey64Value(UIntPtr inHive, String inKeyName, RegSAM in32or64key, String inPropertyName)
		{
			int hkey = 0;
			try
			{
				uint lResult = RegOpenKeyEx(RegHive.HKEY_LOCAL_MACHINE, inKeyName, 0, (int)RegSAM.QueryValue | (int)in32or64key, out hkey);
				if (0 != lResult) return null;
				uint lpType = 0;
				uint lpcbData = 1024;
				StringBuilder AgeBuffer = new StringBuilder(1024);
				RegQueryValueEx(hkey, inPropertyName, 0, ref lpType, AgeBuffer, ref lpcbData);
				string Age = AgeBuffer.ToString();
				return Age;
			}
			finally
			{
				if (0 != hkey) RegCloseKey(hkey);
			}
		}
		static public bool CheckRegKey64Valid(UIntPtr inHive, String inKeyName)
		{
			return CheckRegKey64Valid(inHive, inKeyName, RegSAM.WOW64_64Key);
		}
		static public bool GetRegKey32Valid(UIntPtr inHive, String inKeyName)
		{
			return CheckRegKey64Valid(inHive, inKeyName, RegSAM.WOW64_32Key);
		}
		static public bool CheckRegKey64Valid(UIntPtr inHive, String inKeyName, RegSAM in32or64key)
		{
			int hkey = 0;
			try
			{
				uint lResult = RegOpenKeyEx(RegHive.HKEY_LOCAL_MACHINE, inKeyName, 0, (int)RegSAM.QueryValue | (int)in32or64key, out hkey);
				if (0 != lResult) return false;
				return true;
			}
			finally
			{
				if (0 != hkey) RegCloseKey(hkey);
			}
		}
		#endregion

		#region Enums
		#endregion
	}
}