/*=========================================================================
 *
 *  Copyright UMC Utrecht and contributors
 *
 *  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
 *
 *        http://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 elxPowell_hxx
#define elxPowell_hxx

#include "elxPowell.h"
#include <iomanip>
#include <string>
#include <vnl/vnl_math.h>

namespace elastix
{

/**
 * ***************** BeforeRegistration ***********************
 */

template <typename TElastix>
void
Powell<TElastix>::BeforeRegistration()
{
  /** Add the target cell "stepsize" to IterationInfo.*/
  this->AddTargetCellToIterationInfo("2:Metric");
  this->AddTargetCellToIterationInfo("3:StepSize");
  this->AddTargetCellToIterationInfo("4:||Gradient||");

  /** Format the metric and stepsize as floats */
  this->GetIterationInfoAt("2:Metric") << std::showpoint << std::fixed;
  this->GetIterationInfoAt("3:StepSize") << std::showpoint << std::fixed;
  this->GetIterationInfoAt("4:||Gradient||") << std::showpoint << std::fixed;

} // end BeforeRegistration


/**
 * ***************** BeforeEachResolution ***********************
 */

template <typename TElastix>
void
Powell<TElastix>::BeforeEachResolution()
{
  /** Get the current resolution level.*/
  auto level = static_cast<unsigned int>(this->m_Registration->GetAsITKBaseType()->GetCurrentLevel());

  /** Set the value tolerance.*/
  double valueTolerance = 1e-8;
  this->m_Configuration->ReadParameter(valueTolerance, "ValueTolerance", this->GetComponentLabel(), level, 0);
  this->SetValueTolerance(valueTolerance);

  /** Set the MaximumStepLength.*/
  double maxStepLength = 16.0 / std::pow(2.0, static_cast<int>(level));
  this->m_Configuration->ReadParameter(maxStepLength, "MaximumStepLength", this->GetComponentLabel(), level, 0);
  this->SetStepLength(maxStepLength);

  /** Set the MinimumStepLength.*/
  double stepTolerance = 0.5 / std::pow(2.0, static_cast<int>(level));
  this->m_Configuration->ReadParameter(stepTolerance, "StepTolerance", this->GetComponentLabel(), level, 0);
  this->SetStepTolerance(stepTolerance);

  /** Set the maximumNumberOfIterations.*/
  unsigned int maximumNumberOfIterations = 500;
  this->m_Configuration->ReadParameter(
    maximumNumberOfIterations, "MaximumNumberOfIterations", this->GetComponentLabel(), level, 0);
  this->SetMaximumIteration(maximumNumberOfIterations);

} // end BeforeEachResolution


/**
 * ***************** AfterEachIteration *************************
 */

template <typename TElastix>
void
Powell<TElastix>::AfterEachIteration()
{
  /** Print some information */
  this->GetIterationInfoAt("2:Metric") << this->GetValue();
  this->GetIterationInfoAt("3:StepSize") << this->GetStepLength();
} // end AfterEachIteration


/**
 * ***************** AfterEachResolution *************************
 */

template <typename TElastix>
void
Powell<TElastix>::AfterEachResolution()
{
  /**
   * enum   StopConditionType {   GradientMagnitudeTolerance = 1, StepTooSmall,
   * ImageNotAvailable, CostFunctionError, MaximumNumberOfIterations
   */
  std::string stopcondition = this->GetStopConditionDescription();

  /** Print the stopping condition */
  log::info(std::ostringstream{} << "Stopping condition: " << stopcondition << ".");

} // end AfterEachResolution


/**
 * ******************* AfterRegistration ************************
 */

template <typename TElastix>
void
Powell<TElastix>::AfterRegistration()
{
  /** Print the best metric value */
  double bestValue = this->GetValue();
  log::info(std::ostringstream{} << '\n' << "Final metric value  = " << bestValue);

} // end AfterRegistration


/**
 * ******************* SetInitialPosition ***********************
 */

template <typename TElastix>
void
Powell<TElastix>::SetInitialPosition(const ParametersType & param)
{
  /** Override the implementation in itkOptimizer.h, to
   * ensure that the scales array and the parameters
   * array have the same size.
   */

  /** Call the Superclass' implementation. */
  this->Superclass1::SetInitialPosition(param);

  /** Set the scales array to the same size if the size has been changed */
  if (const std::size_t paramsize{ param.Size() }; this->GetScales().Size() != paramsize)
  {
    this->SetScales(ScalesType(paramsize, 1.0));
  }

  /** \todo to optimizerbase? */

} // end SetInitialPosition


} // end namespace elastix

#endif // end #ifndef elxPowell_hxx
