/*=========================================================================
 *
 *  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 itkVariableSizeMatrix_hxx
#define itkVariableSizeMatrix_hxx

#include "itkNumericTraits.h"

namespace itk
{
template <typename T>
VariableSizeMatrix<T>::VariableSizeMatrix(unsigned int rows, unsigned int cols)
  : m_Matrix(rows, cols)
{}

/**
 *  Product by a Vector
 */
template <typename T>
Array<T> VariableSizeMatrix<T>::operator*(const Array<T> & vect) const
{
  unsigned int rows = this->Rows();
  unsigned int cols = this->Cols();

  if (vect.Size() != cols)
  {
    itkGenericExceptionMacro("Matrix with " << this->Cols() << " columns cannot be "
                                            << "multiplied with array of length: " << vect.Size());
  }

  Array<T> result(rows);
  for (unsigned int r = 0; r < rows; ++r)
  {
    T sum{};
    for (unsigned int c = 0; c < cols; ++c)
    {
      sum += m_Matrix(r, c) * vect[c];
    }
    result[r] = sum;
  }
  return result;
}

/**
 *  Product by a matrix
 */
template <typename T>
VariableSizeMatrix<T> VariableSizeMatrix<T>::operator*(const Self & matrix) const
{
  if (this->Cols() != matrix.Rows())
  {
    itkGenericExceptionMacro("Matrix with size (" << this->Rows() << ',' << this->Cols()
                                                  << ") cannot be multiplied by matrix with size (" << matrix.Rows()
                                                  << ',' << matrix.Cols() << ')');
  }
  Self result;
  result = m_Matrix * matrix.m_Matrix;
  return result;
}

/**
 *  Matrix Addition
 */
template <typename T>
VariableSizeMatrix<T>
VariableSizeMatrix<T>::operator+(const Self & matrix) const
{
  if ((matrix.Rows() != this->Rows()) || (matrix.Cols() != this->Cols()))
  {
    itkGenericExceptionMacro("Matrix with size (" << matrix.Rows() << ',' << matrix.Cols()
                                                  << ") cannot be added to a matrix with size (" << this->Rows() << ','
                                                  << this->Cols() << ')');
  }

  Self result(this->Rows(), this->Cols());
  for (unsigned int r = 0; r < this->Rows(); ++r)
  {
    for (unsigned int c = 0; c < this->Cols(); ++c)
    {
      result.m_Matrix(r, c) = m_Matrix(r, c) + matrix.m_Matrix(r, c);
    }
  }
  return result;
}

/**
 *  Matrix Addition in-place
 */
template <typename T>
const VariableSizeMatrix<T> &
VariableSizeMatrix<T>::operator+=(const Self & matrix)
{
  if ((matrix.Rows() != this->Rows()) || (matrix.Cols() != this->Cols()))
  {
    itkGenericExceptionMacro("Matrix with size (" << matrix.Rows() << ',' << matrix.Cols()
                                                  << ") cannot be added to a matrix with size (" << this->Rows() << ','
                                                  << this->Cols() << ')');
  }

  for (unsigned int r = 0; r < this->Rows(); ++r)
  {
    for (unsigned int c = 0; c < this->Cols(); ++c)
    {
      m_Matrix(r, c) += matrix.m_Matrix(r, c);
    }
  }
  return *this;
}

/**
 *  Matrix Subtraction
 */
template <typename T>
VariableSizeMatrix<T>
VariableSizeMatrix<T>::operator-(const Self & matrix) const
{
  if ((matrix.Rows() != this->Rows()) || (matrix.Cols() != this->Cols()))
  {
    itkGenericExceptionMacro("Matrix with size (" << matrix.Rows() << ',' << matrix.Cols()
                                                  << ") cannot be subtracted from matrix with size (" << this->Rows()
                                                  << ',' << this->Cols() << ')');
  }

  Self result(this->Rows(), this->Cols());
  for (unsigned int r = 0; r < this->Rows(); ++r)
  {
    for (unsigned int c = 0; c < this->Cols(); ++c)
    {
      result.m_Matrix(r, c) = m_Matrix(r, c) - matrix.m_Matrix(r, c);
    }
  }
  return result;
}

/**
 *  Matrix subtraction in-place
 */
template <typename T>
const VariableSizeMatrix<T> &
VariableSizeMatrix<T>::operator-=(const Self & matrix)
{
  if ((matrix.Rows() != this->Rows()) || (matrix.Cols() != this->Cols()))
  {
    itkGenericExceptionMacro("Matrix with size (" << matrix.Rows() << ',' << matrix.Cols()
                                                  << ") cannot be subtracted from matrix with size (" << this->Rows()
                                                  << ',' << this->Cols() << ')');
  }

  for (unsigned int r = 0; r < this->Rows(); ++r)
  {
    for (unsigned int c = 0; c < this->Cols(); ++c)
    {
      m_Matrix(r, c) -= matrix.m_Matrix(r, c);
    }
  }
  return *this;
}

template <typename T>
VariableSizeMatrix<T> &
VariableSizeMatrix<T>::operator-()
{
  for (unsigned int r = 0; r < this->Rows(); ++r)
  {
    for (unsigned int c = 0; c < this->Cols(); ++c)
    {
      m_Matrix(r, c) = -m_Matrix(r, c);
    }
  }
  return *this;
}

/**
 *  Product by a vnl_matrix
 */
template <typename T>
vnl_matrix<T> VariableSizeMatrix<T>::operator*(const vnl_matrix<T> & matrix) const
{
  return m_Matrix * matrix;
}

/**
 *  Product by a matrix
 */
template <typename T>
void
VariableSizeMatrix<T>::operator*=(const Self & matrix)
{
  m_Matrix *= matrix.m_Matrix;
}

/**
 *  Product by a vnl_matrix
 */
template <typename T>
void
VariableSizeMatrix<T>::operator*=(const vnl_matrix<T> & matrix)
{
  m_Matrix *= matrix;
}

/**
 *  Product by a vnl_vector
 */
template <typename T>
vnl_vector<T> VariableSizeMatrix<T>::operator*(const vnl_vector<T> & vc) const
{
  return m_Matrix * vc;
}
} // end namespace itk

#endif
