/*=========================================================================
 *
 *  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.
 *
 *=========================================================================*/

#include "itkListSample.h"
#include "itkKdTreeGenerator.h"
#include "itkTestingMacros.h"

#include <iostream>
#include <fstream>


int
itkKdTreeTest2(int argc, char * argv[])
{

  if (argc < 4)
  {
    std::cerr << "Missing parameters." << std::endl;
    std::cerr << "Usage: " << itkNameOfTestExecutableMacro(argv);
    std::cerr << " pointsInputFile  bucketSize graphvizDotOutputFile" << std::endl;
    return EXIT_FAILURE;
  }

  constexpr unsigned int Dimension = 2;
  using MeasurementValueType = float;

  using MeasurementVectorType = itk::Vector<MeasurementValueType, Dimension>;

  using SampleType = itk::Statistics::ListSample<MeasurementVectorType>;
  auto sample = SampleType::New();
  sample->SetMeasurementVectorSize(Dimension);

  MeasurementVectorType mv;
  MeasurementVectorType queryPoint;

  std::ifstream pntFile;

  pntFile.open(argv[1], std::ios_base::in | std::ios_base::binary);

  pntFile >> mv[0] >> mv[1];

  do
  {
    sample->PushBack(mv);
    pntFile >> mv[0] >> mv[1];
  } while (!pntFile.eof());

  pntFile.close();

  using TreeGeneratorType = itk::Statistics::KdTreeGenerator<SampleType>;
  auto treeGenerator = TreeGeneratorType::New();

  const unsigned int bucketSize = std::stoi(argv[2]);

  treeGenerator->SetSample(sample);
  treeGenerator->SetBucketSize(bucketSize);
  treeGenerator->Update();

  using TreeType = TreeGeneratorType::KdTreeType;

  bool testFailed = false;

  TreeType::Pointer tree = treeGenerator->GetOutput();

  using DistanceMetricType = itk::Statistics::EuclideanDistanceMetric<MeasurementVectorType>;
  auto distanceMetric = DistanceMetricType::New();

  DistanceMetricType::OriginType origin(Dimension);

  //
  // Print out the tree structure to the console
  //
  tree->PrintTree(std::cout);


  for (unsigned int k = 0; k < sample->Size(); ++k)
  {

    queryPoint = sample->GetMeasurementVector(k);

    for (unsigned int i = 0; i < sample->GetMeasurementVectorSize(); ++i)
    {
      origin[i] = queryPoint[i];
    }

    std::cout << "----------------------------------" << std::endl;

    std::cout << "Origin = " << origin << std::endl;

    distanceMetric->SetOrigin(origin);

    unsigned int                           numberOfNeighbors = 1;
    TreeType::InstanceIdentifierVectorType neighbors;

    tree->Search(queryPoint, numberOfNeighbors, neighbors);

    std::cout << "kd-tree knn search result:" << std::endl
              << "query point = [" << queryPoint << ']' << std::endl
              << "k = " << numberOfNeighbors << std::endl;
    std::cout << "measurement vector : distance" << std::endl;

    for (unsigned int i = 0; i < numberOfNeighbors; ++i)
    {
      const double distance = distanceMetric->Evaluate(tree->GetMeasurementVector(neighbors[i]));

      std::cout << '[' << tree->GetMeasurementVector(neighbors[i]) << "] : " << distance << std::endl;

      if (distance > itk::Math::eps)
      {
        testFailed = true;
      }
    }
  }


  //
  // Plot out the tree structure to the console in the format used by Graphviz dot
  //
  std::ofstream plotFile;
  plotFile.open(argv[3]);
  tree->PlotTree(plotFile);
  plotFile.close();


  if (testFailed)
  {
    std::cerr << "Incorrect distance was found" << std::endl;
    return EXIT_FAILURE;
  }

  return EXIT_SUCCESS;
}