/*=========================================================================
*
*  Copyright Insight Software Consortium
*
*  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.
*
*=========================================================================*/

/**
 * Test program for GPUGradientAnisotropicDiffusionImageFilter class
 */
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkGradientAnisotropicDiffusionImageFilter.h"
#include "itkTimeProbe.h"
#include "itkImageRegionIterator.h"

#include "itkOpenCLUtil.h"
#include "itkGPUImage.h"
#include "itkGPUKernelManager.h"
#include "itkGPUContextManager.h"
#include "itkGPUImageToImageFilter.h"
#include "itkGPUGradientAnisotropicDiffusionImageFilter.h"

template< unsigned int VImageDimension >
int runGPUGradientAnisotropicDiffusionImageFilterTest(const std::string& inFile, const std::string& outFile)
{
  typedef float InputPixelType;
  typedef float OutputPixelType;

  typedef itk::GPUImage< InputPixelType,  VImageDimension >   InputImageType;
  typedef itk::GPUImage< OutputPixelType, VImageDimension >   OutputImageType;

  typedef itk::ImageFileReader< InputImageType  >  ReaderType;
  typedef itk::ImageFileWriter< OutputImageType >  WriterType;

  typename ReaderType::Pointer reader = ReaderType::New();
  typename WriterType::Pointer writer = WriterType::New();

  reader->SetFileName( inFile );
  writer->SetFileName( outFile );

  // Create CPU/GPU anistorpic diffusion filter
  typedef itk::GradientAnisotropicDiffusionImageFilter< InputImageType, OutputImageType > CPUAnisoDiffFilterType;
  typedef itk::GPUGradientAnisotropicDiffusionImageFilter< InputImageType, OutputImageType > GPUAnisoDiffFilterType;

  typename CPUAnisoDiffFilterType::Pointer CPUFilter = CPUAnisoDiffFilterType::New();
  typename GPUAnisoDiffFilterType::Pointer GPUFilter = GPUAnisoDiffFilterType::New();

  reader->Update();

  // -------

  // test 1~8 threads for CPU
  std::vector<int> nThreadVec;
  nThreadVec.push_back(1);
  nThreadVec.push_back(2);
  nThreadVec.push_back(4);
  nThreadVec.push_back(8);
  nThreadVec.push_back(128);

  for(unsigned int idx = 0; idx < nThreadVec.size(); idx++)
  {
    int nThreads = nThreadVec[idx];
    itk::TimeProbe cputimer;
    cputimer.Start();

    CPUFilter->SetNumberOfThreads( nThreads );

    CPUFilter->SetInput( reader->GetOutput() );
    CPUFilter->SetNumberOfIterations( 10 );
    CPUFilter->SetTimeStep( 0.0625 );//125 );
    CPUFilter->SetConductanceParameter( 3.0 );
    CPUFilter->UseImageSpacingOn();
    CPUFilter->Update();

    cputimer.Stop();

    std::cout << "CPU Anisotropic diffusion took " << cputimer.GetMean() << " seconds with "
              << CPUFilter->GetNumberOfThreads() << " threads.\n" << std::endl;

    // -------

    if (idx == nThreadVec.size()-1)
    {
      itk::TimeProbe gputimer;
      gputimer.Start();

      GPUFilter->SetInput( reader->GetOutput() );
      GPUFilter->SetNumberOfIterations( 10 );
      GPUFilter->SetTimeStep( 0.0625 );//125 );
      GPUFilter->SetConductanceParameter( 3.0 );
      GPUFilter->UseImageSpacingOn();
      try
      {
        GPUFilter->Update();
      }
      catch (itk::ExceptionObject& excp)
      {
        std::cout << "Caught exception during GPUFilter->Update() " << excp << std::endl;
        return EXIT_FAILURE;
      }

      try
      {
        GPUFilter->GetOutput()->UpdateBuffers(); // synchronization point
      }
      catch (itk::ExceptionObject& excp)
      {
        std::cout << "Caught exception during GPUFilter->GetOutput()->UpdateBuffers() " << excp << std::endl;
        return EXIT_FAILURE;
      }


      gputimer.Stop();
      std::cout << "GPU Anisotropic diffusion took " << gputimer.GetMean() << " seconds.\n" << std::endl;

      // ---------------
      // RMS Error check
      // ---------------

      double diff = 0;
      unsigned int nPix = 0;
      itk::ImageRegionIterator<OutputImageType> cit(CPUFilter->GetOutput(), CPUFilter->GetOutput()->GetLargestPossibleRegion());
      itk::ImageRegionIterator<OutputImageType> git(GPUFilter->GetOutput(), GPUFilter->GetOutput()->GetLargestPossibleRegion());

      for(cit.GoToBegin(), git.GoToBegin(); !cit.IsAtEnd(); ++cit, ++git)
      {
        double err = (double)(cit.Get()) - (double)(git.Get());
        diff += err*err;
        nPix++;
      }
      writer->SetInput( GPUFilter->GetOutput() ); // copy GPU->CPU implicilty

      // execute pipeline filter and write output
      writer->Update();

      if (nPix > 0)
      {
        double RMSError = sqrt( diff / (double)nPix );
        std::cout << "RMS Error : " << RMSError << std::endl;
        double RMSThreshold = 2.5e-6;
        if (itk::Math::isnan(RMSError))
        {
          std::cout << "RMS Error is NaN! nPix: " << nPix << std::endl;
          return EXIT_FAILURE;
        }
        if (RMSError > RMSThreshold)
        {
          std::cout << "RMS Error exceeds threshold (" << RMSThreshold << ")" << std::endl;
          return EXIT_FAILURE;
        }
      }
      else
      {
        std::cout << "No pixels in output!" << std::endl;
        return EXIT_FAILURE;
      }
    }

  }

  GPUFilter = ITK_NULLPTR; // explicit GPU object destruction test
  itk::GPUContextManager::GetInstance()->DestroyInstance(); // GPUContextManager singleton destruction test
  return EXIT_SUCCESS;
}

int itkGPUGradientAnisotropicDiffusionImageFilterTest(int argc, char *argv[])
{
  if(!itk::IsGPUAvailable())
  {
    std::cerr << "OpenCL-enabled GPU is not present." << std::endl;
    return EXIT_FAILURE;
  }

  if( argc <  3 )
  {
    std::cerr << "Error: missing arguments" << std::endl;
    std::cerr << "inputfile outputfile [num_dimensions]" << std::endl;
    return EXIT_FAILURE;
  }

  std::string inFile( argv[1] );
  std::string outFile( argv[2] );

  unsigned int dim = 3;
  if( argc >= 4 )
  {
    dim = atoi( argv[3] );
  }

  if( dim == 2 )
  {
    return runGPUGradientAnisotropicDiffusionImageFilterTest<2>(inFile, outFile);
  }
  else if( dim == 3 )
  {
    return runGPUGradientAnisotropicDiffusionImageFilterTest<3>(inFile, outFile);
  }
  else
  {
    std::cerr << "Error: only 2 or 3 dimensions allowed, " << dim << " selected." << std::endl;
    return EXIT_FAILURE;
  }
}