/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef itkOpenCVVideoCapture_h
#define itkOpenCVVideoCapture_h

#include <string>

// Include the required header with OpenCV > 2.X
#include "opencv2/core/version.hpp"
#if !defined(CV_VERSION_EPOCH)
// OpenCV 3.x
#  include "opencv2/videoio.hpp"
#else
// OpenCV 2.4.x
#  include "highgui.h"
#endif

#include "itkVideoStream.h"

namespace itk
{

/**
 * \class OpenCVVideoCapture
 * \brief This class implements OpenCV's VideoCapture API and takes an itk
 * VideoStream as input
 *
 * This implementation of cv::VideoCapture provides the additional method
 * open( itk::VideoStream* ) to "open" video data from an ITK pipeline. The
 * traditional open methods will throw exceptions, so it can only be used to
 * access the output of an ITK video pipeline from an OpenCV capture context.
 *
 * \ingroup ITKVideoBridgeOpenCV
 */
template <typename TVideoStream>
class ITK_TEMPLATE_EXPORT OpenCVVideoCapture : public cv::VideoCapture
{
public:
  using VideoStreamType = TVideoStream;
  using Self = OpenCVVideoCapture<VideoStreamType>;
  using FrameType = typename VideoStreamType::FrameType;
  using PixelType = typename FrameType::PixelType;
  static constexpr unsigned int Dimensions = FrameType::ImageDimension;
  /** Constructor that initializes internal VideoStream to null */
  OpenCVVideoCapture();

  /** Constructor that takes a VideoStream as input */
  OpenCVVideoCapture(VideoStreamType * videoStream);

  /** Destructor that does nothing. The VideoStream will be freed by the source
   * that generated it. */
  virtual ~OpenCVVideoCapture() {}

  /** \see LightObject::GetNameOfClass() */
  itkVirtualGetNameOfClassMacro(OpenCVVideoCapture);

  // Open, close functionality

  /** overload reading from file and camera just to throw exceptions */
  virtual bool
  open(const std::string &)
  {
    itkExceptionMacro("itk::OpenCVVideoCapture::open(filename) -> If you just want "
                      "to read from a file, use cv::VideoCapture since there is nothing to be "
                      "gained using itk's version.");
  }

  virtual bool
  open(int)
  {
    itkExceptionMacro("itk::OpenCVVideoCapture::open(device) -> If you just want "
                      "to read from a device, use cv::VideoCapture since there is nothing to be "
                      "gained using itk's version.");
  }

  /** Add an open method that takes a TemporalDataObject. This checks to make
   * sure that it can be cast to a VideoStream */
  virtual bool
  open(VideoStreamType * videoStream);

  /** Check if the VideoStream is null */
  virtual bool
  isOpened() const
  {
    return m_VideoStream == 0;
  }

  /** Just set the internal pointer to null. Let the upstream filters take care
   * of actually freeing the memory */
  virtual void
  release();

  // Frame access

  /** Grab the next frame from the VideoStream */
  virtual bool
  grab();

  /** Access the current frame of the VideoStream */
  virtual bool
  retrieve(cv::Mat & image, int channel = 0);

  /** Stream the next frame into the provided image.
   * Equivalent to grab() + retrieve(image, 0) */
  virtual Self &
  operator>>(cv::Mat & image);

  /** Non-operator version of >>'s functionality */
  virtual bool
  read(cv::Mat & image);

  // Properties

  /** Set a property */
  virtual bool
  set(int propId, double value);

  /** Get a property */
  virtual double
  get(int propId);

protected:
  /** Internal VideoStream */
  VideoStreamType * m_VideoStream{};

  /** Property members */
  double m_FpS{};
  int    m_FourCC{};

}; // end class VideoCapture

} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkOpenCVVideoCapture.hxx"
#endif

#endif