//=========================================================================
//  Copyright (c) Kitware, Inc.
//  All rights reserved.
//  See LICENSE.txt for details.
//
//  This software is distributed WITHOUT ANY WARRANTY; without even
//  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
//  PURPOSE.  See the above copyright notice for more information.
//=========================================================================

#include "smtk/attribute/Attribute.h"
#include "smtk/attribute/ComponentItem.h"
#include "smtk/attribute/Definition.h"
#include "smtk/attribute/DoubleItem.h"
#include "smtk/attribute/FileItem.h"
#include "smtk/attribute/IntItem.h"
#include "smtk/attribute/Resource.h"
#include "smtk/attribute/ResourceItem.h"
#include "smtk/attribute/StringItem.h"
#include "smtk/attribute/VoidItem.h"

#include "smtk/io/AttributeReader.h"
#include "smtk/io/ExportMesh.h"
#include "smtk/io/ImportMesh.h"
#include "smtk/io/Logger.h"
#include "smtk/io/WriteMesh.h"

#include "smtk/mesh/core/PointField.h"
#include "smtk/mesh/utility/Create.h"
#include "smtk/mesh/utility/Metrics.h"

#include "smtk/model/EntityRef.h"
#include "smtk/model/Face.h"
#include "smtk/model/Model.h"
#include "smtk/model/utility/InterpolateField.h"

#include "smtk/session/mesh/Resource.h"
#include "smtk/session/mesh/operators/Import.h"

#include "smtk/session/vtk/RegisterVTKBackend.h"
#include "smtk/session/vtk/Resource.h"
#include "smtk/session/vtk/operators/Import.h"

#include "smtk/resource/Component.h"

#include "smtk/common/testing/cxx/helpers.h"

//force to use filesystem version 3
#define BOOST_FILESYSTEM_VERSION 3
#include <boost/filesystem.hpp>
using namespace boost::filesystem;

#include <array>

namespace
{
// SMTK_DATA_DIR is a define setup by cmake
std::string data_root = SMTK_DATA_DIR;
std::string write_root = SMTK_SCRATCH_DIR;

void cleanup(const std::string& file_path)
{
  //first verify the file exists
  ::boost::filesystem::path path(file_path);
  if (::boost::filesystem::is_regular_file(path))
  {
    //remove the file_path if it exists.
    ::boost::filesystem::remove(path);
  }
}

// A test attribute description that allows association and has a double item.
// clang-format off
const char* testInput = R"(
<?xml version="1.0"?>
<SMTK_AttributeResource Version="4">
  <Definitions>
    <AttDef Type="Example">
      <AssociationsDef>
        <Accepts><Resource Name="smtk::model::Resource"/></Accepts>
      </AssociationsDef>
      <ItemDefinitions>
        <Double Name="interpolation value"/>
      </ItemDefinitions>
    </AttDef>
  </Definitions>
  <Attributes>
    <Att Name="att1" Type="Example"/>
    <Att Name="att2" Type="Example"/>
    <Att Name="att3" Type="Example"/>
    <Att Name="att4" Type="Example"/>
  </Attributes>
</SMTK_AttributeResource>)";
// clang-format on

// A testing structure to perform regression testing against the results of
// interpolation.
class HistogramFieldData
{
public:
  HistogramFieldData(std::size_t nBins, double min, double max)
    : m_min(min)
    , m_max(max)
  {
    m_hist.resize(nBins, 0);
  }

  const std::vector<std::size_t>& histogram() const { return m_hist; }

protected:
  std::vector<std::size_t> m_hist;
  double m_min;
  double m_max;
};

class HistogramPointFieldData
  : public smtk::mesh::PointForEach
  , public HistogramFieldData
{
public:
  HistogramPointFieldData(std::size_t nBins, double min, double max, smtk::mesh::PointField& pf)
    : HistogramFieldData(nBins, min, max)
    , m_pointField(pf)
  {
  }

  void forPoints(
    const smtk::mesh::HandleRange& pointIds,
    std::vector<double>& /*xyz*/,
    bool& /*coordinatesModified*/) override
  {
    std::vector<double> values(pointIds.size());
    m_pointField.get(pointIds, values.data());
    for (auto& value : values)
    {
      std::size_t bin = static_cast<std::size_t>((value - m_min) / (m_max - m_min) * m_hist.size());

      ++m_hist[bin];
    }
  }

protected:
  smtk::mesh::PointField& m_pointField;
};

smtk::session::mesh::Resource::Ptr readMeshResource(const std::string& importFilePath)
{
  smtk::session::mesh::Resource::Ptr resource;
  {
    auto importOp = smtk::session::mesh::Import::create();

    if (!importOp)
    {
      std::cerr << "No import operator\n";
      return nullptr;
    }

    importOp->parameters()->findFile("filename")->setValue(importFilePath);
    importOp->parameters()->findVoid("construct hierarchy")->setIsEnabled(false);

    smtk::operation::Operation::Result importOpResult = importOp->operate();

    if (
      importOpResult->findInt("outcome")->value() !=
      static_cast<int>(smtk::operation::Operation::Outcome::SUCCEEDED))
    {
      std::cerr << "Import operator failed\n";
      return nullptr;
    }

    // Retrieve the resulting resource
    smtk::attribute::ResourceItemPtr resourceItem =
      std::dynamic_pointer_cast<smtk::attribute::ResourceItem>(
        importOpResult->findResource("resourcesCreated"));

    // Access the generated resource
    resource = std::dynamic_pointer_cast<smtk::session::mesh::Resource>(resourceItem->value());

    // Retrieve the resulting model
    smtk::attribute::ComponentItemPtr componentItem =
      std::dynamic_pointer_cast<smtk::attribute::ComponentItem>(
        importOpResult->findComponent("model"));

    // Access the generated model
    smtk::model::Entity::Ptr modelEntity =
      std::dynamic_pointer_cast<smtk::model::Entity>(componentItem->value());

    smtk::model::Model model = modelEntity->referenceAs<smtk::model::Model>();

    if (!model.isValid())
    {
      std::cerr << "Import operator returned an invalid model\n";
      return nullptr;
    }
  }
  return resource;
}

smtk::session::vtk::Resource::Ptr readVTKResource(const std::string& importFilePath)
{
  smtk::session::vtk::RegisterVTKBackend::registerClass();

  smtk::session::vtk::Resource::Ptr resource;
  {
    auto importOp = smtk::session::vtk::Import::create();

    if (!importOp)
    {
      std::cerr << "No import operator\n";
      return nullptr;
    }

    importOp->parameters()->findFile("filename")->setValue(importFilePath);

    smtk::operation::Operation::Result importOpResult = importOp->operate();

    if (
      importOpResult->findInt("outcome")->value() !=
      static_cast<int>(smtk::operation::Operation::Outcome::SUCCEEDED))
    {
      std::cerr << "Import operator failed\n";
      return nullptr;
    }

    // Retrieve the resulting resource
    smtk::attribute::ResourceItemPtr resourceItem =
      std::dynamic_pointer_cast<smtk::attribute::ResourceItem>(
        importOpResult->findResource("resourcesCreated"));

    // Access the generated resource
    resource = std::dynamic_pointer_cast<smtk::session::vtk::Resource>(resourceItem->value());

    // Retrieve the resulting model
    smtk::attribute::ComponentItemPtr componentItem =
      std::dynamic_pointer_cast<smtk::attribute::ComponentItem>(
        importOpResult->findComponent("model"));

    // Access the generated model
    smtk::model::Entity::Ptr modelEntity =
      std::dynamic_pointer_cast<smtk::model::Entity>(componentItem->value());

    smtk::model::Model model = modelEntity->referenceAs<smtk::model::Model>();

    if (!model.isValid())
    {
      std::cerr << "Import operator returned an invalid model\n";
      return nullptr;
    }
  }
  return resource;
}
} // namespace

int TestInterpolateAnnotatedValues(int argc, char* argv[])
{
  (void)argc;
  (void)argv;

  for (int testNumber = 0; testNumber < 2; ++testNumber)
  {
    std::string importFilePath(data_root);
    importFilePath += "/mesh/2d/test2D.2dm";

    // Import a model resource.
    smtk::model::Resource::Ptr resource;
    std::array<double, 6> extent;
    if (testNumber == 0)
    {
      resource = readMeshResource(importFilePath);
      extent = smtk::mesh::utility::extent(
        std::dynamic_pointer_cast<smtk::session::mesh::Resource>(resource)->resource()->meshes());
    }
    else
    {
      smtk::mesh::Resource::Ptr meshResource = smtk::mesh::Resource::create();
      smtk::io::importMesh(importFilePath, meshResource);
      extent = smtk::mesh::utility::extent(meshResource->meshes());

      std::string write_path(write_root);
      write_path += "/" + smtk::common::UUID::random().toString() + ".exo";
      smtk::io::exportMesh(write_path, meshResource);

      resource = readVTKResource(write_path);
      cleanup(write_path);
    }

    if (resource == nullptr)
    {
      return 1;
    }

    // Access all of the model's faces
    smtk::model::EntityRefs currentEnts =
      resource->entitiesMatchingFlagsAs<smtk::model::EntityRefs>(smtk::model::FACE);
    if (currentEnts.empty())
    {
      std::cerr << "No faces!" << std::endl;
      return 1;
    }

    // Arrange the model faces with a consistent ordering
    std::vector<smtk::model::EntityRef> eRefs(currentEnts.begin(), currentEnts.end());
    std::sort(
      eRefs.begin(),
      eRefs.end(),
      [](const smtk::model::EntityRef& lhs, const smtk::model::EntityRef& rhs) {
        return lhs.name() < rhs.name();
      });

    // Construct the test attribute resource
    smtk::attribute::ResourcePtr resptr = smtk::attribute::Resource::create();
    smtk::attribute::Resource& attResource(*resptr.get());
    smtk::io::Logger logger;
    smtk::io::AttributeReader reader;

    if (reader.readContents(resptr, testInput, logger))
    {
      std::cerr << "Encountered Errors while reading input data\n";
      std::cerr << logger.convertToString();
      return 2;
    }

    // Access the attribute resource's definitions
    std::vector<smtk::attribute::DefinitionPtr> defs;
    attResource.definitions(defs);
    if (defs.size() != 1)
    {
      std::cerr << "Unexpected number of definitions: " << defs.size() << "\n";
      std::cerr << logger.convertToString();
      return 2;
    }

    // Access the attribute resource's attributes
    std::vector<smtk::attribute::AttributePtr> atts;
    attResource.attributes(atts);
    if (atts.size() != 4)
    {
      std::cerr << "Unexpected number of attributes: " << atts.size() << "\n";
      std::cerr << logger.convertToString();
      return 2;
    }

    // For each attribute, associate the attribute to a model face and assign it
    // a value
    for (std::size_t i = 0; i < 4; i++)
    {
      atts[i]->associate(eRefs[i].component());
      atts[i]->findDouble("interpolation value")->setValue(i + 1.);
    }

    // Construct a grid of sample points
    std::array<double, 3> origin = { extent[0], extent[2], extent[4] };
    std::array<double, 3> size = { (extent[1] - extent[0]),
                                   (extent[3] - extent[2]),
                                   (extent[5] - extent[4]) };

    // Offset the grid from the model surface
    origin[2] += .25;

    smtk::mesh::ResourcePtr gridResource = smtk::mesh::Resource::create();

    // Construct a mapping from a unit box to the input box
    std::function<std::array<double, 3>(std::array<double, 3>)> fn = [&](std::array<double, 3> x) {
      return std::array<double, 3>(
        { { origin[0] + size[0] * x[0], origin[1] + size[1] * x[1], origin[2] + size[2] * x[2] } });
    };

    std::array<std::size_t, 2> disc = { { 50, 20 } };

    std::array<smtk::mesh::MeshSet, 5> sampleGrid =
      smtk::mesh::utility::createUniformGrid(gridResource, disc, fn);

    // Remove superfluous meshes (we are only interested in the surface mesh, not
    // its edges)
    for (std::size_t i = 1; i < 5; i++)
    {
      gridResource->removeMeshes(sampleGrid[i]);
    }

    // Access the points of the sample grid
    std::vector<double> pts;
    sampleGrid[0].points().get(pts);

    // Compute the interpolation weights for the sample grid points
    std::vector<smtk::model::Weights> weights = smtk::model::computeWeights(pts, defs[0]);

    // Compute the interpolated values for the sample grid points
    std::vector<double> values =
      smtk::model::inverseDistanceWeighting(weights, "interpolation value", 2);

    // For testing, assign the interpolated values to the sample grid as a point
    // field
    sampleGrid[0].createPointField(
      "interpolation", 1, smtk::mesh::FieldType::Double, values.data());

    bool debug = false;
    if (debug)
    {
      //write out the mesh.
      std::string write_path(write_root);
      write_path += "/" + smtk::common::UUID::random().toString() + ".h5m";

      smtk::io::WriteMesh write;
      bool result = write(write_path, gridResource);
      if (!result)
      {
        test(result, "failed to properly write out a valid hdf5 resource");
      }
    }

    // Histogram the resulting points and compare against expected values.
    std::vector<std::size_t> histogram;
    smtk::mesh::PointField pointField = gridResource->meshes().pointField("interpolation");
    HistogramPointFieldData histogramPointFieldData(10, .5, 4.5, pointField);
    smtk::mesh::for_each(gridResource->meshes().points(), histogramPointFieldData);
    histogram = histogramPointFieldData.histogram();

    std::array<std::size_t, 10> expectedForMeshSession = {
      { 0, 301, 84, 112, 69, 55, 109, 100, 241, 0 }
    };
    std::array<std::size_t, 10> expectedForVTKSession = {
      { 0, 303, 81, 112, 70, 55, 109, 101, 240, 0 }
    };

    std::size_t counter = 0;
    for (auto& bin : histogram)
    {
      if (
        bin !=
        (testNumber == 0 ? expectedForMeshSession[counter++] : expectedForVTKSession[counter++]))
      {
        std::cerr << "\"interpolate annotations\" produced unexpected results\n";
        return 1;
      }
    }
  }

  return 0;
}
