/*=========================================================================
 *
 *  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 itkStringTools_hxx
#define itkStringTools_hxx


#include <sstream>

namespace itk
{

/////////////////////////////////////////////////////////////////////////////
// helper functions for converting a string to/from a std::vector
/////////////////////////////////////////////////////////////////////////////

/**
 * Function to convert a string to a vector of type std::vector<T>.
 * Number of elements to read is given by the parameter 'count':
 *   = 0, get the number of elements to read from data.size();
 *   > 0, read number of 'count' elements, and resize the data if necessary;
 *   < 0, default value (-1), automatically compute the number from the input stream.
 *
 * An exception will be thrown if errors were encountered during the conversion.
 */
template <typename T>
std::string &
StringTools::ToData(std::string & s, std::vector<T> & data, int count)
{
  std::istringstream iss(s, std::istringstream::in);

  if (count < 0)
  {
    // compute the number of elements to be read from the input stream
    while (iss.good()) // loop until error occurred or reach end of stream
    {
      T value{};
      if (iss >> value)
      {
        data.push_back(value);
      }
    }
    if (!iss.eof())
    {
      iss.exceptions(iss.failbit | iss.badbit);
    }
  }
  else
  {
    iss.exceptions(iss.failbit | iss.badbit);

    // the number of elements to be read is provided by count or, if count is 0, data.size()
    if (count == 0)
    {
      count = static_cast<int>(data.size());
    }
    if (static_cast<size_t>(count) > data.size())
    {
      data.resize(static_cast<size_t>(count));
    }
    for (size_t i = 0; i < static_cast<size_t>(count); ++i)
    {
      T value{};
      iss >> value;
      data[i] = value;
    }
  }

  return s;
}

/**
 * Functions to convert a vector of type std::vector<T> to a string.
 * An exception will be thrown if errors were encountered during the conversion.
 */
template <typename T>
std::string &
StringTools::FromData(std::string & s, const std::vector<T> & data)
{
  std::ostringstream oss(std::ostringstream::out);
  oss.exceptions(oss.badbit);
  for (size_t i = 0; i < data.size(); ++i)
  {
    oss << ' ' << data[i];
  }

  s.append(oss.str());
  return s;
}

/////////////////////////////////////////////////////////////////////////////
// helper functions for converting a string to/from an itk::Array
/////////////////////////////////////////////////////////////////////////////

/**
 * Function to convert a string to an array of type itk::Array<T>.
 * Number of elements to read is given by the parameter 'count':
 *   = 0, get the number of elements to read from data.size();
 *   > 0, read number of 'count' elements, and resize the data if necessary;
 *   < 0, default value (-1), automatically compute the number from the input stream.
 *
 * An exception will be thrown if errors were encountered during the conversion.
 */
template <typename T>
std::string &
StringTools::ToData(std::string & s, Array<T> & data, int count)
{
  std::istringstream iss(s, std::istringstream::in);

  if (count < 0)
  {
    // compute the number of elements to be read from the input stream
    std::vector<T> v;
    while (iss.good()) // loop until error occurred or reach end of stream
    {
      T value{};
      if (iss >> value)
      {
        v.push_back(value);
      }
    }

    if (!iss.eof())
    {
      iss.exceptions(iss.failbit | iss.badbit);
    }

    data.SetSize(static_cast<typename Array<T>::SizeValueType>(v.size()));
    // Note: The data-cast to unsigned int is required
    //       because itk::Array only supports 'unsigned int' number of elements.
    for (unsigned int i = 0; i < v.size(); ++i)
    {
      data[i] = v[i];
    }
  }
  else
  {
    iss.exceptions(iss.failbit | iss.badbit);
    // the number of elements to be read is provided by count or, if count is 0, data.size()
    if (count == 0)
    {
      count = static_cast<int>(data.GetSize());
    }
    if (static_cast<size_t>(count) > data.GetSize())
    {
      data.SetSize(static_cast<size_t>(count));
    }
    for (unsigned int i = 0; i < static_cast<unsigned int>(count); ++i)
    {
      T value{};
      iss >> value;
      data[i] = value;
    }
  }

  return s;
}

/**
 * Functions to convert an array of type itk::Array<T> to a string.
 * An exception will be thrown if errors were encountered during the conversion.
 */
template <typename T>
std::string &
StringTools::FromData(std::string & s, const Array<T> & data)
{
  std::ostringstream oss(std::ostringstream::out);
  oss.exceptions(oss.badbit);
  for (unsigned int i = 0; i < static_cast<unsigned int>(data.GetSize()); ++i)
  {
    oss << ' ' << data[i];
  }

  s.append(oss.str());
  return s;
}

/////////////////////////////////////////////////////////////////////////////
// helper functions for converting a string to/from a basic data type
/////////////////////////////////////////////////////////////////////////////

/**
 * Functions to convert a string to a value of basic data type.
 * An exception will be thrown if errors were encountered during the conversion.
 */
template <typename T>
std::string &
StringTools::ToData(std::string & s, T & data)
{
  std::istringstream iss(s, std::istringstream::in);
  iss.exceptions(iss.failbit | iss.badbit);
  iss >> data;

  return s;
}

/**
 * Functions to convert a value of basic data type to a string.
 * An exception will be thrown if errors were encountered during the conversion.
 */
template <typename T>
std::string &
StringTools::FromData(std::string & s, const T & data)
{
  std::ostringstream oss(std::ostringstream::out);
  oss.exceptions(oss.badbit);
  oss << data;

  s.append(oss.str());
  return s;
}

} // namespace itk

#endif // itkStringTools_hxx