//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012-2020 OpenVPN Inc.
//
//    This program is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Affero General Public License Version 3
//    as published by the Free Software Foundation.
//
//    This program is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU Affero General Public License for more details.
//
//    You should have received a copy of the GNU Affero General Public License
//    along with this program in the COPYING file.
//    If not, see <http://www.gnu.org/licenses/>.
//

#ifndef OPENVPN_WIN_EVENT_H
#define OPENVPN_WIN_EVENT_H

#include <windows.h>

#include <string>

#include <openvpn/buffer/bufhex.hpp>
#include <openvpn/win/winerr.hpp>
#include <openvpn/win/scoped_handle.hpp>

namespace openvpn {
  namespace Win {

    // Wrap a standard Windows Event object
    class Event
    {
    public:
      explicit Event(BOOL manual_reset=TRUE)
      {
	event.reset(::CreateEvent(NULL, manual_reset, FALSE, NULL));
	if (!event.defined())
	  {
	    const Win::LastError err;
	    OPENVPN_THROW_EXCEPTION("Win::Event: cannot create Windows event: " << err.message());
	  }
      }

      std::string duplicate_local()
      {
	HANDLE new_handle;
	if (!::DuplicateHandle(GetCurrentProcess(),
			      event(),
			      GetCurrentProcess(),
			      &new_handle,
			      0,
			      FALSE,
			      DUPLICATE_SAME_ACCESS))
	  {
	    const Win::LastError err;
	    OPENVPN_THROW_EXCEPTION("Win::Event: DuplicateHandle failed: " << err.message());
	  }
	return BufHex::render(new_handle);
      }

      void signal_event()
      {
	if (event.defined())
	  {
	    ::SetEvent(event());
	    event.close();
	  }
      }

      void release_event()
      {
	event.close();
      }

      HANDLE operator()() const
      {
	return event();
      }

      void reset(HANDLE h)
      {
	event.reset(h);
      }

    private:
      ScopedHANDLE event;
    };

    // Windows event object that automatically signals in the destructor
    struct DestroyEvent : public Event
    {
      ~DestroyEvent()
      {
	signal_event();
      }
    };

  }
}

#endif