using System;
using Microsoft.Win32;


namespace RobvanderWoude
{
	internal class WinVerCL
	{
		static readonly string progver = "1.00";


		static int Main( string[] args )
		{
			// Old NT versioning system, as in VER command
			string os = Environment.OSVersion.VersionString;
			Console.WriteLine( );
			Console.WriteLine( os );
			Console.WriteLine( );

			// Friendly version name, as in WinVer command
			string displayversion, osbuild, productname, ubr;
			try
			{
				// try forcing accessing 64-bit registry first, otherwise the program may choose 32-bit even on 64-bit systems
				using ( RegistryKey hklm64 = RegistryKey.OpenBaseKey( RegistryHive.LocalMachine, RegistryView.Registry64 ) )
				{
					using ( RegistryKey currentversion = hklm64.OpenSubKey( "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion" ) )
					{
						productname = currentversion.GetValue( "Productname", "Unknown" ).ToString( );
						displayversion = currentversion.GetValue( "DisplayVersion", "" ).ToString( );
						osbuild = currentversion.GetValue( "CurrentBuildNumber", "Unknown" ).ToString( );
						ubr = currentversion.GetValue( "UBR", "" ).ToString( );
					}
				}
			}
			catch
			{
				using ( RegistryKey hklm32 = RegistryKey.OpenBaseKey( RegistryHive.LocalMachine, RegistryView.Registry32 ) )
				{
					using ( RegistryKey currentversion = hklm32.OpenSubKey( "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion" ) )
					{
						productname = currentversion.GetValue( "Productname", "Unknown" ).ToString( );
						displayversion = currentversion.GetValue( "DisplayVersion", "" ).ToString( );
						osbuild = currentversion.GetValue( "CurrentBuildNumber", "Unknown" ).ToString( );
						ubr = currentversion.GetValue( "UBR", "" ).ToString( );
					}
				}
			}
			if ( !string.IsNullOrWhiteSpace( ubr ) )
			{
				osbuild = String.Format( "{0}.{1}", osbuild, ubr );
			}
			Console.WriteLine( "{0} {1} (OS Build {2})", productname, displayversion, osbuild );
			Console.WriteLine( );

			return 0;
		}
	}
}