/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  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
 *
 *         http://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 itkOneHiddenLayerBackPropagationNeuralNetwork_h
#define itkOneHiddenLayerBackPropagationNeuralNetwork_h

#include "itkMultilayerNeuralNetworkBase.h"
#include "itkBackPropagationLayer.h"
#include "itkSigmoidTransferFunction.h"
#include "itkLogSigmoidTransferFunction.h"
#include "itkTanSigmoidTransferFunction.h"
#include "itkHardLimitTransferFunction.h"
#include "itkSignedHardLimitTransferFunction.h"
#include "itkGaussianTransferFunction.h"
#include "itkIdentityTransferFunction.h"
#include "itkSumInputFunction.h"


namespace itk
{
namespace Statistics
{
/** \class OneHiddenLayerBackPropagationNeuralNetwork
 * \brief This is the itkOneHiddenLayerBackPropagationNeuralNetwork class.
 *
 * \ingroup ITKNeuralNetworks
 */

template<typename TMeasurementVector, typename TTargetVector>
class ITK_TEMPLATE_EXPORT OneHiddenLayerBackPropagationNeuralNetwork :
    public MultilayerNeuralNetworkBase<TMeasurementVector, TTargetVector, BackPropagationLayer<TMeasurementVector, TTargetVector> >
{
public:
  typedef OneHiddenLayerBackPropagationNeuralNetwork       Self;
  typedef MultilayerNeuralNetworkBase<TMeasurementVector, TTargetVector, BackPropagationLayer<TMeasurementVector, TTargetVector> >
                                                           Superclass;
  typedef SmartPointer<Self>                               Pointer;
  typedef SmartPointer<const Self>                         ConstPointer;

  typedef typename Superclass::ValueType             ValueType;
  typedef typename Superclass::MeasurementVectorType MeasurementVectorType;
  typedef typename Superclass::TargetVectorType      TargetVectorType;
  typedef typename Superclass::NetworkOutputType     NetworkOutputType;

  typedef typename Superclass::LayerInterfaceType    LayerInterfaceType;
  typedef typename Superclass::LearningLayerType     LearningLayerType;

  typedef typename Superclass::WeightVectorType      WeightVectorType;
  typedef typename Superclass::LayerVectorType       LayerVectorType;

  typedef typename Superclass::TransferFunctionInterfaceType
                                                     TransferFunctionInterfaceType;
  typedef typename Superclass::InputFunctionInterfaceType
                                                     InputFunctionInterfaceType;

  /** Method for creation through the object factory. */
  itkTypeMacro(OneHiddenLayerBackPropagationNeuralNetwork,
               MultilayerNeuralNetworkBase);
  itkNewMacro(Self);

  //Add the layers to the network.
  // 1 input, 1 hidden, 1 output
  void Initialize() ITK_OVERRIDE;

  itkSetMacro(NumOfInputNodes, unsigned int);
  itkGetConstReferenceMacro(NumOfInputNodes, unsigned int);

  itkSetMacro(NumOfFirstHiddenNodes, unsigned int);
  itkGetConstReferenceMacro(NumOfFirstHiddenNodes, unsigned int);

  itkSetMacro(NumOfOutputNodes, unsigned int);
  itkGetConstReferenceMacro(NumOfOutputNodes, unsigned int);

  itkSetMacro(FirstHiddenLayerBias, ValueType);
  itkGetConstReferenceMacro(FirstHiddenLayerBias, ValueType);

//#define __USE_OLD_INTERFACE  Comment out to ensure that new interface works
#ifdef __USE_OLD_INTERFACE
  //Original Function name before consistency naming changes
  inline void SetNumOfHiddenNodes(const unsigned int & x) { SetNumOfFirstHiddenNodes(x); }
  inline unsigned int GetNumOfHiddenNodes(void) const { return GetNumOfFirstHiddenNodes(); }
  inline void SetHiddenLayerBias(const ValueType & bias) { SetFirstHiddenLayerBias(bias); }
  ValueType GetHiddenLayerBias(void) const { return GetFirstHiddenLayerBias();}
#endif
  itkSetMacro(OutputLayerBias, ValueType);
  itkGetConstReferenceMacro(OutputLayerBias, ValueType);

  virtual NetworkOutputType GenerateOutput(TMeasurementVector samplevector) ITK_OVERRIDE;

  void SetInputFunction(InputFunctionInterfaceType* f);
  void SetInputTransferFunction(TransferFunctionInterfaceType* f);
#ifdef __USE_OLD_INTERFACE
  //Original Function name before consistency naming changes
  inline void SetHiddenTransferFunction(TransferFunctionInterfaceType* f) { SetFirstHiddenTransferFunction (f); }
#endif
  void SetFirstHiddenTransferFunction(TransferFunctionInterfaceType* f);
  void SetOutputTransferFunction(TransferFunctionInterfaceType* f);

protected:

  OneHiddenLayerBackPropagationNeuralNetwork();
  virtual ~OneHiddenLayerBackPropagationNeuralNetwork() ITK_OVERRIDE {};

  /** Method to print the object. */
  virtual void PrintSelf( std::ostream& os, Indent indent ) const ITK_OVERRIDE;

private:

  unsigned int m_NumOfInputNodes;
  unsigned int m_NumOfFirstHiddenNodes;
  unsigned int m_NumOfOutputNodes;

  ValueType m_FirstHiddenLayerBias;
  ValueType m_OutputLayerBias;

  typename InputFunctionInterfaceType::Pointer    m_InputFunction;
  typename TransferFunctionInterfaceType::Pointer m_InputTransferFunction;
  typename TransferFunctionInterfaceType::Pointer m_FirstHiddenTransferFunction;
  typename TransferFunctionInterfaceType::Pointer m_OutputTransferFunction;
};

} // end namespace Statistics
} // end namespace itk

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

#endif