/*
 * Copyright (C) 2005-2020 Centre National d'Etudes Spatiales (CNES)
 *
 * 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.
 */

#include "otbImage.h"
#include "otbVectorImage.h"
#include "otbImageFileReader.h"
#include "otbImageFileWriter.h"

#include "otbProjectiveProjectionImageFilter.h"
#include "otbMatrixImageFilter.h"
#include "otbVectorImageToMatrixImageFilter.h"
#include "otbStreamingStatisticsImageFilter.h"
#include "otbStreamingStatisticsVectorImageFilter.h"

const unsigned int Dimension = 2;
typedef double     PixelType;
typedef double     PrecisionType;

typedef otb::Image<PixelType, Dimension>       ImageType;
typedef otb::VectorImage<PixelType, Dimension> VectorImageType;
typedef otb::ImageFileReader<VectorImageType> ReaderType;
typedef otb::ProjectiveProjectionImageFilter<VectorImageType, VectorImageType, PrecisionType> ProjectiveProjectionImageFilterType;
typedef otb::MatrixImageFilter<VectorImageType, VectorImageType> MatrixImageFilterType;
typedef otb::VectorImageToMatrixImageFilter<VectorImageType>       VectorImageToMatrixImageFilterType;
typedef otb::ImageFileWriter<VectorImageType>                      WriterType;
typedef otb::StreamingStatisticsVectorImageFilter<VectorImageType> StreamingStatisticsVectorImageFilterType;
typedef otb::StreamingStatisticsImageFilter<ImageType>             StreamingStatisticsImageFilterType;

typedef StreamingStatisticsVectorImageFilterType::MatrixType MatrixType;


int otbProjectiveProjectionTestHighSNR(int itkNotUsed(argc), char* argv[])
{
  const char*        inputImage   = argv[1];
  const unsigned int nbEndmembers = atoi(argv[2]);
  const char*        outputImage  = argv[3];


  ReaderType::Pointer readerImage = ReaderType::New();
  readerImage->SetFileName(inputImage);

  std::cout << "Computing image stats" << std::endl;
  StreamingStatisticsVectorImageFilterType::Pointer statsInput = StreamingStatisticsVectorImageFilterType::New();

  statsInput->SetInput(readerImage->GetOutput());
  statsInput->Update();

  std::cout << "Computing SVD of correlation matrix" << std::endl;
  // Take the correlation matrix
  vnl_matrix<PrecisionType> R = statsInput->GetCorrelation().GetVnlMatrix();

  // Apply SVD
  vnl_svd<PrecisionType>    svd(R);
  vnl_matrix<PrecisionType> U  = svd.U();
  vnl_matrix<PrecisionType> Ud = U.get_n_columns(0, nbEndmembers).transpose();

  std::cout << "Apply dimensionnality reduction" << std::endl;
  // Xd = Ud.'*M;
  MatrixImageFilterType::Pointer mulUd = MatrixImageFilterType::New();
  mulUd->SetInput(readerImage->GetOutput());
  mulUd->SetMatrix(Ud);
  mulUd->MatrixByVectorOn();
  mulUd->UpdateOutputInformation();

  VectorImageType::Pointer Xd = mulUd->GetOutput();

  // Compute mean(Xd)
  std::cout << "Compute mean(Xd)" << std::endl;
  StreamingStatisticsVectorImageFilterType::Pointer statsXd = StreamingStatisticsVectorImageFilterType::New();
  statsXd->SetInput(Xd);
  statsXd->Update();
  VectorImageType::PixelType Xdmean = statsXd->GetMean();

  // Compute Xd ./ repmat( sum( Xd .* repmat(u, [1 N]) ) , [d 1]);
  // -> divides each pixel component by the dot product <Xd(i, j), mean(Xd)>
  std::cout << "Compute projective projection" << std::endl;
  ProjectiveProjectionImageFilterType::Pointer proj = ProjectiveProjectionImageFilterType::New();
  proj->SetInput(Xd);
  proj->GetModifiableFunctor().SetProjectionDirection(Xdmean);

  std::cout << "Write output" << std::endl;
  WriterType::Pointer writer = WriterType::New();
  writer->SetFileName(outputImage);
  writer->SetInput(proj->GetOutput());
  writer->Update();

  return EXIT_SUCCESS;
}
