/*=========================================================================
 *
 *  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 itkNumericTraitsVariableLengthVectorPixel_h
#define itkNumericTraitsVariableLengthVectorPixel_h

#include "itkVariableLengthVector.h"

// This work is part of the National Alliance for Medical Image Computing
// (NAMIC), funded by the National Institutes of Health through the NIH Roadmap
// for Medical Research, Grant U54 EB005149.

namespace itk
{
/**
 * \brief Define numeric traits for VariableLengthVector.
 * \tparam T Component type of VariableLengthVector
 *
 * We provide here a generic implementation based on creating types of
 * VariableLengthVector whose components are the types of the NumericTraits from
 * the original VariableLengthVector components. This implementation require
 * support for partial specializations, since it is based on the
 * concept that:
 *   NumericTraits<VariableLengthVector< T > >  is defined piecewise by
 *   VariableLengthVector< NumericTraits< T > >
 *
 * \note The Zero(), One(), min() and max() methods here take
 * references to a pixel as input.  This is due to the fact that the
 * length of the VariableLengthVector is not known until
 * run-time. Since the most common use of Zero and One is for
 * comparison purposes or initialization of sums etc, this might just
 * as easily be re-written with a pixel passed in as a reference and
 * the length is inferred from this pixel.
 *
 * \sa NumericTraits
 * \ingroup DataRepresentation
 * \ingroup ITKCommon
 */
template <typename T>
class NumericTraits<VariableLengthVector<T>>
{
public:
  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;

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

  using Self = VariableLengthVector<T>;

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

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

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

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

  /** Type for real-valued scalar operations. */
  using RealType = VariableLengthVector<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 & a)
  {
    Self b(a.Size());

    b.Fill(NumericTraits<T>::max());
    return b;
  }

  static const Self
  min(const Self & a)
  {
    Self b(a.Size());

    b.Fill(NumericTraits<T>::min());
    return b;
  }

  static const Self
  ZeroValue(const Self & a)
  {
    Self b(a.Size());

    b.Fill(T{});
    return b;
  }

  static const Self
  OneValue(const Self & a)
  {
    Self b(a.Size());

    b.Fill(NumericTraits<T>::OneValue());
    return b;
  }

  static const Self
  NonpositiveMin(const Self & a)
  {
    Self b(a.Size());
    b.Fill(NumericTraits<T>::NonpositiveMin());
    return b;
  }

  static bool
  IsPositive(const Self & a)
  {
    bool flag = false;
    for (unsigned int i = 0; i < GetLength(a); ++i)
    {
      if (a[i] > ValueType{})
      {
        flag = true;
      }
    }
    return flag;
  }

  static bool
  IsNonpositive(const Self & a)
  {
    bool flag = false;
    for (unsigned int i = 0; i < GetLength(a); ++i)
    {
      if (!(a[i] > 0.0))
      {
        flag = true;
      }
    }
    return flag;
  }

  static bool
  IsNegative(const Self & a)
  {
    bool flag = false;
    for (unsigned int i = 0; i < GetLength(a); ++i)
    {
      if (a[i] < ValueType{})
      {
        flag = true;
      }
    }
    return flag;
  }

  static bool
  IsNonnegative(const Self & a)
  {
    bool flag = false;
    for (unsigned int i = 0; i < GetLength(a); ++i)
    {
      if (!(a[i] < 0.0))
      {
        flag = true;
      }
    }
    return flag;
  }

  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;


  /** Resize the input vector to the specified size. */
  static void
  SetLength(VariableLengthVector<T> & m, const unsigned int s)
  {
    m.SetSize(s);
    m.Fill(T{});
  }

  /** Return the size of the vector. */
  static unsigned int
  GetLength(const VariableLengthVector<T> & m)
  {
    return m.GetSize();
  }

  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 < GetLength(v); ++i)
    {
      mv[i] = v[i];
    }
  }
};
} // end namespace itk

#endif // itkNumericTraitsVariableLengthVector_h
