/*=========================================================================
 *
 *  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 itkPyCommand_h
#define itkPyCommand_h

#include "itkCommand.h"

// The python header defines _POSIX_C_SOURCE without a preceding #undef
#undef _POSIX_C_SOURCE
#undef _XOPEN_SOURCE
#include "Python.h"

namespace itk
{

/** \class PyCommand
 *  \brief Command subclass that calls a Python callable object, e.g.
 *  a Python function.
 *
 * With this class, arbitrary Python callable objects (e.g. functions)
 * can be associated with an instance to be used in AddObserver calls.
 * This is analogous to itk::TclCommand, but then a tad more flexible.;)
 *
 * This class was contributed by Charl P. Botha <cpbotha |AT| ieee.org>
 */
class PyCommand : public Command
{
public:
  ///! Standard "Self" typedef.
  using Self = PyCommand;

  ///! Smart pointer type alias support
  using Pointer = SmartPointer<Self>;

  ///! Run-time type information (and related methods).
  itkOverrideGetNameOfClassMacro(PyCommand);

  ///! Method for creation through the object factory.
  itkNewMacro(Self);

  /**
   * Assign a Python callable object to be used.  You don't have to keep
   * a binding to the callable, PyCommand will also take out a reference
   * to make sure the Callable sticks around.
   */
  void
  SetCommandCallable(PyObject * obj);

  PyObject *
  GetCommandCallable();

  void
  Execute(Object *, const EventObject &);
  void
  Execute(const Object *, const EventObject &);

protected:
  PyCommand();
  ~PyCommand();
  void
  PyExecute();
  PyCommand(const Self &); // Not implemented.
  PyCommand &
  operator=(const Self &); // Not implemented.

private:
  PyObject * m_Object;
  PyObject * m_EmptyArgumentList;
};


} // namespace itk

#endif // _itkPyCommand_h