/*=========================================================================
 *
 *  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 itkMixtureModelComponentBase_hxx
#define itkMixtureModelComponentBase_hxx

namespace itk::Statistics
{
template <typename TSample>
MixtureModelComponentBase<TSample>::MixtureModelComponentBase()
  : m_Sample(nullptr)
  , m_MinimalParametersChange(1.0e-06)
  , m_MembershipFunction(nullptr)
  , m_ParametersModified(true)
{}

template <typename TSample>
void
MixtureModelComponentBase<TSample>::PrintSelf(std::ostream & os, Indent indent) const
{
  Superclass::PrintSelf(os, indent);

  os << indent << "Sample: ";
  if (m_Sample != nullptr)
  {
    os << m_Sample << std::endl;
  }
  else
  {
    os << "not set." << std::endl;
  }

  os << indent << "Membership Function: ";
  if (m_MembershipFunction != nullptr)
  {
    os << m_MembershipFunction << std::endl;
  }
  else
  {
    os << "not instantiated yet." << std::endl;
  }

  os << indent << "Weights Array: ";
  os << m_Weights << std::endl;

  os << indent << "Parameters are modified: " << m_ParametersModified << std::endl;
}

template <typename TSample>
void
MixtureModelComponentBase<TSample>::SetSample(const TSample * sample)
{
  m_Sample = sample;
  m_Weights = WeightArrayType(m_Sample->Size());
}

template <typename TSample>
const TSample *
MixtureModelComponentBase<TSample>::GetSample() const
{
  return m_Sample;
}

template <typename TSample>
void
MixtureModelComponentBase<TSample>::SetParameters(const ParametersType & parameters)
{
  if (m_Parameters != parameters)
  {
    m_Parameters = parameters;
    this->AreParametersModified(true);
  }
}

template <typename TSample>
bool
MixtureModelComponentBase<TSample>::AreParametersModified()
{
  return m_ParametersModified;
}

template <typename TSample>
void
MixtureModelComponentBase<TSample>::AreParametersModified(bool flag)
{
  m_ParametersModified = flag;
}

template <typename TSample>
void
MixtureModelComponentBase<TSample>::SetMembershipFunction(MembershipFunctionType * function)
{
  m_MembershipFunction = function;
}

template <typename TSample>
auto
MixtureModelComponentBase<TSample>::GetMembershipFunction() -> MembershipFunctionType *
{
  return m_MembershipFunction;
}

template <typename TSample>
inline double
MixtureModelComponentBase<TSample>::Evaluate(MeasurementVectorType & measurements)
{
  return m_MembershipFunction->Evaluate(measurements);
}

template <typename TSample>
inline void
MixtureModelComponentBase<TSample>::SetWeight(unsigned int index, double value)
{
  if (index < m_Weights.size())
  {
    (m_Weights)[index] = value;
  }
  else
  {
    itkExceptionStringMacro("Weight array is not allocated.");
  }
}

template <typename TSample>
inline double
MixtureModelComponentBase<TSample>::GetWeight(unsigned int index) const
{
  if (index < m_Weights.Size())
  {
    return m_Weights[index];
  }

  itkExceptionStringMacro("Weight array is not allocated.");
}

template <typename TSample>
void
MixtureModelComponentBase<TSample>::Update()
{
  this->GenerateData();
}
} // namespace itk::Statistics

#endif
