/*
 * Copyright (C) 1999-2011 Insight Software Consortium
 * Copyright (C) 2005-2020 Centre National d'Etudes Spatiales (CNES)
 * Copyright (C) 2016-2019 IRSTEA
 *
 * This file is part of Orfeo Toolbox
 *
 *     https://www.orfeo-toolbox.org/
 *
 * 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
 *
 * 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 __StreamingStatisticsMosaicFilter_hxx
#define __StreamingStatisticsMosaicFilter_hxx

#include "otbStreamingStatisticsMosaicFilter.h"

namespace otb
{

template <class TInputImage, class TOutputImage, class TInternalValueType>
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::PersistentStatisticsMosaicFilter()
{

  // allocate the data objects for the outputs which are
  // just decorators around pixel types
  // 1: means
  // 2: stdevs
  // 3: means of products
  // 4: mins
  // 5: maxs
  for (int i = 1; i < 6; ++i)
  {
    typename RealMatrixListObjectType::Pointer output = static_cast<RealMatrixListObjectType*>(this->MakeOutput(i).GetPointer());
    this->itk::ProcessObject::SetNthOutput(i, output.GetPointer());
  }

  // allocate the data objects for the outputs which are
  // just decorators around real matrices
  //
  // 6: count
  typename RealMatrixObjectType::Pointer output = static_cast<RealMatrixObjectType*>(this->MakeOutput(6).GetPointer());
  this->itk::ProcessObject::SetNthOutput(6, output.GetPointer());
}

/*
 * Make output
 */
template <class TInputImage, class TOutputImage, class TInternalValueType>
typename itk::DataObject::Pointer
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::MakeOutput(DataObjectPointerArraySizeType output)
{
  itkDebugMacro(<< "Entering MakeOutput(" << output << ")");
  if (output == 0)
  {
    return static_cast<itk::DataObject*>(TOutputImage::New().GetPointer());
  }
  else if (output == 6)
  {
    return static_cast<itk::DataObject*>(RealMatrixObjectType::New().GetPointer());
  }
  return static_cast<itk::DataObject*>(RealMatrixListObjectType::New().GetPointer());
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetMeansOutput()
{
  return static_cast<RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(1));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetStdsOutput()
{
  return static_cast<RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(2));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetMeansOfProductsOutput()
{
  return static_cast<RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(3));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetMinsOutput()
{
  return static_cast<RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(4));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetMaxsOutput()
{
  return static_cast<RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(5));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetAreasOutput()
{
  return static_cast<RealMatrixObjectType*>(this->itk::ProcessObject::GetOutput(6));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
const typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetMeansOutput() const
{
  return static_cast<const RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(1));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
const typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetStdsOutput() const
{
  return static_cast<const RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(2));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
const typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetMeansOfProductsOutput() const
{
  return static_cast<const RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(3));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
const typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetMinsOutput() const
{
  return static_cast<const RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(4));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
const typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixListObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetMaxsOutput() const
{
  return static_cast<const RealMatrixListObjectType*>(this->itk::ProcessObject::GetOutput(5));
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
const typename PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::RealMatrixObjectType*
PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::GetAreasOutput() const
{
  return static_cast<const RealMatrixObjectType*>(this->itk::ProcessObject::GetOutput(6));
}

/**
 * Reset() implementation
 */
template <class TInputImage, class TOutputImage, class TInternalValueType>
void PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::Reset()
{
  itkDebugMacro(<< "Entering Reset()");

  Superclass::GenerateOutputInformation();

  // Prepare threads result
  const unsigned int numberOfThreads = this->GetNumberOfThreads();
  const unsigned int nBands          = this->GetNumberOfBands();
  const unsigned int nbImages        = this->GetNumberOfInputImages();

  itkDebugMacro(<< "\nN threads: " << numberOfThreads << "\nN bands: " << nBands << "\nN images: " << nbImages);

  m_InternalThreadResults.clear();
  for (unsigned int threadId = 0; threadId < numberOfThreads; threadId++)
  {
    // Create a clean empty container for each thread
    ThreadResultsContainer threadResult(nBands, nbImages * nbImages);
    m_InternalThreadResults.push_back(threadResult);
  }
}

template <class TInputImage, class TOutputImage, class TInternalValueType>
void PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::AllocateOutputs()
{
  itkDebugMacro(<< "Entering AllocateOutputs()");
  // This is commented to prevent the streaming of the whole image for the first stream strip
  // It shall not cause any problem because the output image of this filter is not intended to be used.
  // InputImagePointer image = const_cast< TInputImage * >( this->GetInput() );
  // this->GraftOutput( image );
  // Nothing that needs to be allocated for the remaining outputs
}

/*
 * Synthetize() implementation
 */
template <class TInputImage, class TOutputImage, class TInternalValueType>
void PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::Synthetize()
{
  itkDebugMacro(<< "Entering Synthetize()");

  const unsigned int nBands   = Superclass::GetNumberOfBands();
  const unsigned int nbImages = this->GetNumberOfInputImages();

  // Merge threads result
  ThreadResultsContainer finalResults = ThreadResultsContainer(nBands, nbImages * nbImages);
  for (const auto& res : m_InternalThreadResults)
  {
    finalResults.Update(res);
  }

  // Compute final outputs
  m_Means.clear();
  m_Stds.clear();
  m_ProdMeans.clear();
  m_Mins.clear();
  m_Maxs.clear();
  m_Area = RealMatrixType(nbImages, nbImages, 0);

  for (unsigned int band = 0; band < nBands; band++)
  {
    RealMatrixType mean(nbImages, nbImages, 0);
    RealMatrixType prodmean(nbImages, nbImages, 0);
    RealMatrixType stdev(nbImages, nbImages, 0);
    RealMatrixType min(nbImages, nbImages, itk::NumericTraits<InputImageInternalPixelType>::max());
    RealMatrixType max(nbImages, nbImages, itk::NumericTraits<InputImageInternalPixelType>::NonpositiveMin());

    for (unsigned int i = 0; i < nbImages; i++)
    {
      for (unsigned int j = 0; j < nbImages; j++)
      {

        const InternalValueType count  = finalResults.m_count[i * nbImages + j];
        const InternalValueType sum    = finalResults.m_sum[band][i * nbImages + j];
        const InternalValueType cosum  = finalResults.m_cosum[band][i * nbImages + j];
        const InternalValueType sqSum  = finalResults.m_sqSum[band][i * nbImages + j];
        const InternalValueType minVal = finalResults.m_min[band][i * nbImages + j];
        const InternalValueType maxVal = finalResults.m_max[band][i * nbImages + j];

        // Update area
        m_Area[i][j] = count;

        // Update Min and Max
        if (minVal < min[i][j])
          min[i][j] = minVal;
        if (maxVal > max[i][j])
          max[i][j] = maxVal;

        // Update Mean, Std and Mean of products
        if (count > 0)
        {
          mean[i][j]     = sum / (static_cast<InternalValueType>(count));
          prodmean[i][j] = cosum / (static_cast<InternalValueType>(count));

          // Unbiased estimate
          InternalValueType variance = (sqSum - (sum * sum / static_cast<InternalValueType>(count))) / (static_cast<InternalValueType>(count) - 1);
          if (variance > 0)
          {
            stdev[i][j] = vcl_sqrt(variance);
          }
        }
      }
    }
    m_Means.push_back(mean);
    m_Stds.push_back(stdev);
    m_ProdMeans.push_back(prodmean);
    m_Mins.push_back(min);
    m_Maxs.push_back(max);

  } // next band

  this->GetMeansOutput()->Set(m_Means);
  this->GetStdsOutput()->Set(m_Stds);
  this->GetMeansOfProductsOutput()->Set(m_ProdMeans);
  this->GetMinsOutput()->Set(m_Mins);
  this->GetMaxsOutput()->Set(m_Maxs);
  this->GetAreasOutput()->Set(m_Area);
}

/**
 * Processing
 */
template <class TInputImage, class TOutputImage, class TInternalValueType>
void PersistentStatisticsMosaicFilter<TInputImage, TOutputImage, TInternalValueType>::ThreadedGenerateData(const OutputImageRegionType& outputRegionForThread,
                                                                                                           itk::ThreadIdType threadId)
{

  // Debug info
  itkDebugMacro(<< "Actually executing thread " << threadId << " in region " << outputRegionForThread);

  // Support progress methods/callbacks
  itk::ProgressReporter progress(this, threadId, outputRegionForThread.GetNumberOfPixels());

  // Get number of input images
  const unsigned int nbOfInputImages = this->GetNumberOfInputImages();

  // Get number of used inputs
  const unsigned int nbOfUsedInputImages = Superclass::GetNumberOfUsedInputImages();

  // Iterate through the thread region
  IteratorType outputIt(this->GetOutput(), outputRegionForThread);

  // Prepare input pointers, interpolators, and valid regions (input images)
  typename std::vector<InputImageType*>         currentImage;
  typename std::vector<InterpolatorPointerType> interp;
  Superclass::PrepareImageAccessors(currentImage, interp);

  // temporary variables
  OutputImagePointType geoPoint;

  for (outputIt.GoToBegin(); !outputIt.IsAtEnd(); ++outputIt)
  {

    // Update progress
    progress.CompletedPixel();

    // Overlap descriptor for the current pixel (yes/no + value)
    std::vector<unsigned int>        overlapImagesIndices;
    std::vector<InputImagePixelType> overlapPixelValue;

    // Current pixel --> Geographical point
    this->GetOutput()->TransformIndexToPhysicalPoint(outputIt.GetIndex(), geoPoint);

    // Loop on used input images
    for (unsigned int i = 0; i < nbOfUsedInputImages; i++)
    {

      // Check if the point is inside the transformed thread region
      // (i.e. the region in the current input image which match the thread
      // region)
      if (interp[i]->IsInsideBuffer(geoPoint))
      {

        // Compute the interpolated pixel value
        InputImagePixelType interpolatedPixel = interp[i]->Evaluate(geoPoint);

        // Put image index + image pixel value into memory
        if (Superclass::IsPixelNotEmpty(interpolatedPixel))
        {
          overlapImagesIndices.push_back(Superclass::GetUsedInputImageIndice(i));
          overlapPixelValue.push_back(interpolatedPixel);
        }

      } // point inside buffer
    }   // next image

    // Update thread result

    // Nb of overlaps at the current pixel
    unsigned int nbOfOverlappingPixels = overlapImagesIndices.size();

    // Loop on overlapping pixels
    for (unsigned int i = 0; i < nbOfOverlappingPixels; i++)
    {
      // Index of the image whose comes the current overlapping pixel
      unsigned int imageIndex = overlapImagesIndices.at(i);

      // We need to sum this pixel to all overlaps ij
      InputImagePixelType pixel = overlapPixelValue.at(i);

      for (unsigned int j = 0; j < nbOfOverlappingPixels; j++)
      {
        //				if (i!=j)
        {
          // Index of the other image which share this overlapping pixel
          unsigned int otherImageIndex = overlapImagesIndices.at(j);

          // Pixel value of the other image which share this overlapping pixel
          InputImagePixelType otherPixel = overlapPixelValue.at(j);

          // Update
          m_InternalThreadResults.at(threadId).Update(pixel, otherPixel, imageIndex * nbOfInputImages + otherImageIndex);
        }
      }
    } // loop on overlapping pixels

  } // next output pixel
}

} // end namespace gtb

#endif