#include <vtkActor.h>
#include <vtkCommand.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkObjectFactory.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>

#include <vtkTestFilter.h>

class CustomStyle : public vtkInteractorStyleTrackballCamera
{
public:
  static CustomStyle* New();
  vtkTypeMacro(CustomStyle, vtkInteractorStyleTrackballCamera);

  CustomStyle()
  {
    this->Actor = vtkSmartPointer<vtkActor>::New();
    this->Mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    this->Filter = vtkSmartPointer<vtkTestFilter>::New();
  }

  void CallbackFunction(vtkObject* caller, long unsigned int eventId,
                        void* callData)
  {
    std::cout << "CustomStyle::CallbackFunction called." << std::endl;
    vtkPolyData* intermediate = this->Filter->GetIntermediateOutput();
    intermediate->Modified();
    this->Mapper->SetInput(intermediate);
    this->Renderer->ResetCamera();
    this->Renderer->Render();
    this->Interactor->GetRenderWindow()->Render();
  }

  void OnKeyPress()
  {
    // Get the keypress
    std::string key = this->Interactor->GetKeySym();

    if (key == "s") // 'S'tart
    {
      this->Renderer->AddActor(this->Actor);
      this->Filter->AddObserver(this->Filter->RefreshEvent, this,
                                &CustomStyle::CallbackFunction);
      this->Filter->Update();

      this->Actor->SetMapper(this->Mapper);
    }

    // Forward events
    vtkInteractorStyleTrackballCamera::OnKeyPress();
  }

  vtkRenderer* Renderer;
  vtkSmartPointer<vtkActor> Actor;
  vtkSmartPointer<vtkPolyDataMapper> Mapper;
  vtkSmartPointer<vtkTestFilter> Filter;
};
vtkStandardNewMacro(CustomStyle);

int main(int argc, char* argv[])
{
  // Create a renderer, render window, and interactor
  vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow =
      vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
      vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  renderer->SetBackground(1, 1, 1); // White

  vtkSmartPointer<CustomStyle> style = vtkSmartPointer<CustomStyle>::New();
  style->Renderer = renderer;

  renderWindowInteractor->SetInteractorStyle(style);
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}
