/*============================================================================

The Medical Imaging Interaction Toolkit (MITK)

Copyright (c) German Cancer Research Center (DKFZ)
All rights reserved.

Use of this source code is governed by a 3-clause BSD license that can be
found in the LICENSE file.

============================================================================*/

#include <QmitkCallbackFromGUIThread.h>

#include <QApplication>
#include <QEvent>

/// This kind of object is posted into the Qt event queue in order to call some method from the GUI thread
class QmitkCallbackEvent : public QEvent
{
public:
  QmitkCallbackEvent(itk::Command *cmd, itk::EventObject *e) : QEvent(QEvent::User), m_Command(cmd), m_Event(e) {}
  ~QmitkCallbackEvent() override { delete m_Event; }
  itk::Command *command() { return m_Command; }
  itk::EventObject *itkevent() { return m_Event; }
protected:
  itk::Command::Pointer m_Command;
  itk::EventObject *m_Event;
};

QmitkCallbackFromGUIThread::QmitkCallbackFromGUIThread()
{
  mitk::CallbackFromGUIThread::RegisterImplementation(this);
}

QmitkCallbackFromGUIThread::~QmitkCallbackFromGUIThread()
{
}

void QmitkCallbackFromGUIThread::CallThisFromGUIThread(itk::Command *cmd, itk::EventObject *e)
{
  QApplication::instance()->postEvent(this, new QmitkCallbackEvent(cmd, e));
}

bool QmitkCallbackFromGUIThread::event(QEvent *e)
{
  QmitkCallbackEvent *event(dynamic_cast<QmitkCallbackEvent *>(e));

  if (!event)
    return false;

  itk::Command *cmd(event->command());

  if (cmd)
  {
    if (event->itkevent())
    {
      cmd->Execute((const itk::Object *)nullptr, // no itk::Object here
                   *(event->itkevent()));
    }
    else
    {
      const itk::NoEvent dummyEvent;
      cmd->Execute((const itk::Object *)nullptr, // no itk::Object here
                   dummyEvent);
    }
  }

  return true;
}
