import os
import winim/clr
import sugar, strutils

const code = """
  using System;
  using System.Reflection;
  using System.Runtime.InteropServices;
  using System.Management;

  public class EventHelper {
    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
    public delegate void CallbackType([MarshalAs(UnmanagedType.IUnknown)] Object arg);

    public EventArrivedEventHandler MakeHandler(IntPtr cb) {
      return new EventArrivedEventHandler(delegate(Object sender, EventArrivedEventArgs e) {
        Marshal.GetDelegateForFunctionPointer(cb, typeof(CallbackType)).DynamicInvoke(sender);
      });
    }

    public void SetEventArrived(ManagementEventWatcher watcher, EventArrivedEventHandler handler) {
      watcher.EventArrived += handler;
    }
  }
"""

proc eventHandler(sender: ptr IUnknown) {.stdcall.} =
  echo toCLRVariant(sender)
  echo "I'm in the event handler, neat!"

proc test1() =
  var res: CLRVariant = compile(code, ["System.dll", "System.Management.dll"])
  if res.Errors.Count != 0:
    for error in res.Errors:
      echo error
    quit()


  var sysmgmt = load("System.Management")
  var query = sysmgmt.new("System.Management.WqlEventQuery", "SELECT * FROM __InstanceOperationEvent WITHIN 1 WHERE TargetInstance ISA 'Win32_PnPEntity'")
  var watcher = sysmgmt.new("System.Management.ManagementEventWatcher", query)

  var eventHelper = res.CompiledAssembly.new("EventHelper")
  var handler = eventHelper.MakeHandler(eventHandler[])

  eventHelper.SetEventArrived(watcher, handler)

  watcher.Start()

  while true:
    sleep(1000)

test1()