/*=========================================================================
 *
 *  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 itkNumericTraitsDiffusionTensor3DPixel_h
#define itkNumericTraitsDiffusionTensor3DPixel_h

#include "itkNumericTraits.h"
#include "itkDiffusionTensor3D.h"

// This file is meant to define numeric traits for tensor pixels types in itk

namespace itk
{
/**
 * \brief Define numeric traits for DiffusionTensor3D.
 * \tparam T Component type of DiffusionTensor3D
 *
 * We provide here a generic implementation based on creating types of
 * DiffusionTensor3D whose components are the types of the NumericTraits from
 * the original DiffusionTensor3D components. This implementation require
 * support for partial specializations, since it is based on the
 * concept that:
 *   NumericTraits<DiffusionTensor3D< T > >  is defined piecewise by
 *   DiffusionTensor3D< NumericTraits< T > >
 *
 * \sa NumericTraits
 * \ingroup DataRepresentation
 * \ingroup ITKCommon
 */
template <typename T>
class NumericTraits<DiffusionTensor3D<T>>
{
private:
  using ElementAbsType = typename NumericTraits<T>::AbsType;
  using ElementAccumulateType = typename NumericTraits<T>::AccumulateType;
  using ElementFloatType = typename NumericTraits<T>::FloatType;
  using ElementPrintType = typename NumericTraits<T>::PrintType;
  using ElementRealType = typename NumericTraits<T>::RealType;

public:
  /** Return the type of the native component type. */
  using ValueType = T;

  using Self = DiffusionTensor3D<T>;

  /** Unsigned component type */
  using AbsType = DiffusionTensor3D<ElementAbsType>;

  /** Accumulation of addition and multiplication. */
  using AccumulateType = DiffusionTensor3D<ElementAccumulateType>;

  /** Typedef for operations that use floating point instead of real precision
   */
  using FloatType = DiffusionTensor3D<ElementFloatType>;

  /** Return the type that can be printed. */
  using PrintType = DiffusionTensor3D<ElementPrintType>;

  /** Type for real-valued scalar operations. */
  using RealType = DiffusionTensor3D<ElementRealType>;

  /** Type for real-valued scalar operations. */
  using ScalarRealType = ElementRealType;

  /** Measurement vector type */
  using MeasurementVectorType = Self;

  /** Component wise defined element
   *
   * \note minimum value for floating pointer types is defined as
   * minimum positive normalize value.
   */
  static const Self
  max(const Self &)
  {
    return MakeFilled<Self>(NumericTraits<T>::max());
  }

  static const Self
  min(const Self &)
  {
    return MakeFilled<Self>(NumericTraits<T>::min());
  }

  static const Self
  max()
  {
    return MakeFilled<Self>(NumericTraits<T>::max());
  }

  static const Self
  min()
  {
    return MakeFilled<Self>(NumericTraits<T>::min());
  }

  static const Self
  NonpositiveMin()
  {
    return MakeFilled<Self>(NumericTraits<T>::NonpositiveMin());
  }

  static const Self
  ZeroValue()
  {
    return Self{};
  }

  static const Self
  OneValue()
  {
    return MakeFilled<Self>(NumericTraits<T>::OneValue());
  }

  static const Self
  NonpositiveMin(const Self &)
  {
    return NonpositiveMin();
  }

  static const Self
  ZeroValue(const Self &)
  {
    return ZeroValue();
  }

  static const Self
  OneValue(const Self &)
  {
    return OneValue();
  }

  static constexpr bool IsSigned = std::is_signed_v<ValueType>;
  static constexpr bool IsInteger = std::is_integral_v<ValueType>;
  static constexpr bool IsComplex = NumericTraits<ValueType>::IsComplex;

  /** Fixed length vectors cannot be resized, so an exception will
   *  be thrown if the input size is not valid.  In this case, the
   *  only valid size is 6. If the size is valid the tensor will be
   *  filled with zeros. */
  static void
  SetLength(DiffusionTensor3D<T> & m, const unsigned int s)
  {
    if (s != 6)
    {
      itkGenericExceptionMacro("Cannot set the size of a DiffusionTensor3D "
                               "to anything other than 6.");
    }
    m.Fill(T{});
  }

  /** Return the size of the tensor. Always returns 6. */
  static unsigned int
  GetLength(const DiffusionTensor3D<T> &)
  {
    return 6;
  }

  /** Return the size of the tensor. Always returns 6. */
  static unsigned int
  GetLength()
  {
    return 6;
  }

  static void
  AssignToArray(const Self & v, MeasurementVectorType & mv)
  {
    mv = v;
  }

  template <typename TArray>
  static void
  AssignToArray(const Self & v, TArray & mv)
  {
    for (unsigned int i = 0; i < 6; ++i)
    {
      mv[i] = v[i];
    }
  }

  /** \note: the functions are preferred over the member variables as
   * they are defined for all partial specialization
   */
  static const Self ITKCommon_EXPORT Zero;
  static const Self ITKCommon_EXPORT One;
};
} // end namespace itk

#endif // itkNumericTraitsTensorPixel_h
