/*
  To Compile:
    PATH\\TO\\jsc.exe QueryDotnet.js
  
  This example is based on:
     https://docs.microsoft.com/en-us/dotnet/framework/migration-guide/how-to-determine-which-versions-are-installed
 */
import System;
import Microsoft.Win32;

/* The Following is for Checking for .NET version 1 to 4.0 */
function GetVersionFromRegistry(): void 
{
	// Opens the registry key for the .NET Framework entry.
	var ndpKey :RegistryKey = RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, "").
		OpenSubKey("SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\", false);

	/*
	 // As an alternative, if you know the computers you will query are running .NET Framework 4.5 
	 // or later, you can use:
	var ndpKey :RegistryKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).
		OpenSubKey("SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\", false);	
	*/
	for (var versionKeyIndex in ndpKey.GetSubKeyNames())
	{
		var versionKeyName = ndpKey.GetSubKeyNames()[versionKeyIndex];
		if (versionKeyName.StartsWith("v"))
		{
			var versionKey:RegistryKey = ndpKey.OpenSubKey(versionKeyName);
			var name:String = versionKey.GetValue("Version", "");
			var sp:String = versionKey.GetValue("SP", "").ToString();
			var install:String = versionKey.GetValue("Install", "").ToString();
			if (install == "") {
				//no install info, must be later.
				Console.WriteLine(versionKeyName + "  " + name);
			} else 	{
				if (sp != "" && install == "1")
				{
					Console.WriteLine(versionKeyName + "  " + name + "  SP" + sp);
				}
			}
			if (name != "")
			{
				continue;
			}
			
			for (var subKeyIndex in versionKey.GetSubKeyNames())
			{
				var subKeyName = versionKey.GetSubKeyNames()[subKeyIndex]
				var subKey:RegistryKey = versionKey.OpenSubKey(subKeyName);
				name = subKey.GetValue("Version", "");
				if (name != "")
					sp = subKey.GetValue("SP", "").ToString();
				install = subKey.GetValue("Install", "").ToString();
				if (install == ""){
					//no install info, must be later.
					Console.WriteLine(versionKeyName + "  " + name);
				} else {
					if (sp != "" && install == "1")
					{
						Console.WriteLine("  " + subKeyName + "  " + name + "  SP" + sp);
					}
					else if (install == "1")
					{
						Console.WriteLine("  " + subKeyName + "  " + name);
					}
				}
			}
		}
	}
}

GetVersionFromRegistry();

/* The Following Section is to Query for .NET version 4.5 or newer */

function Get45PlusFromRegistry() :void
{
	var subkey:String = "SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\v4\\Full\\";
	var myHKLM :RegistryKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32);
	var ndpKey :RegistryKey = myHKLM.OpenSubKey(subkey,false);
	if (ndpKey != null && ndpKey.GetValue("Release") != null) {
		Console.WriteLine(".NET Framework Version: " + CheckFor45PlusVersion(ndpKey.GetValue("Release")));
	} else {
		Console.WriteLine(".NET Framework Version 4.5 or later is not detected.");
	} 
}

// Checking the version using >= will enable forward compatibility.
function CheckFor45PlusVersion(releaseKey:int) : String
{
	if (releaseKey >= 461808)
		return "4.7.2 or later";
	if (releaseKey >= 461308)
		return "4.7.1";
	if (releaseKey >= 460798)
		return "4.7";
	if (releaseKey >= 394802)
		return "4.6.2";
	if (releaseKey >= 394254)
		return "4.6.1";      
	if (releaseKey >= 393295)
		return "4.6";      
	if (releaseKey >= 379893)
		return "4.5.2";      
	if (releaseKey >= 378675)
		return "4.5.1";      
	if (releaseKey >= 378389)
		return "4.5";      
	// This code should never execute. A non-null release key should mean
	// that 4.5 or later is installed.
	return "No 4.5 or later version detected";
}

Get45PlusFromRegistry()