/*=========================================================================

  Program:   ParaView
  Module:    vtkDataObjectToConduit.cxx

  Copyright (c) Kitware, Inc.
  All rights reserved.
  See Copyright.txt or http://www.paraview.org/HTML/Copyright.html 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 "vtkDataObjectToConduit.h"

#include "vtkAOSDataArrayTemplate.h"
#include "vtkCellData.h"
#include "vtkDataArray.h"
#include "vtkDataObject.h"
#include "vtkDataSet.h"
#include "vtkFieldData.h"
#include "vtkImageData.h"
#include "vtkLogger.h"
#include "vtkPointData.h"
#include "vtkPointSet.h"
#include "vtkPoints.h"
#include "vtkRectilinearGrid.h"
#include "vtkSOADataArrayTemplate.h"
#include "vtkStructuredGrid.h"
#include "vtkTypeFloat32Array.h"
#include "vtkTypeFloat64Array.h"
#include "vtkTypeInt16Array.h"
#include "vtkTypeInt32Array.h"
#include "vtkTypeInt64Array.h"
#include "vtkTypeInt8Array.h"
#include "vtkTypeUInt16Array.h"
#include "vtkTypeUInt32Array.h"
#include "vtkTypeUInt64Array.h"
#include "vtkTypeUInt8Array.h"
#include "vtkUnstructuredGrid.h"

#include <catalyst_conduit.hpp>

namespace
{

//----------------------------------------------------------------------------
bool IsMixedShape(vtkUnstructuredGrid* unstructured_grid)
{
  auto* cell_types = unstructured_grid->GetDistinctCellTypesArray();
  return cell_types->GetNumberOfTuples() > 1;
}

//----------------------------------------------------------------------------
bool IsSignedIntegralType(int data_type)
{
  constexpr bool is_char_type_signed = (CHAR_MIN == SCHAR_MIN) && (CHAR_MAX == SCHAR_MAX);

  return (is_char_type_signed && (data_type == VTK_CHAR)) || (data_type == VTK_SIGNED_CHAR) ||
    (data_type == VTK_SHORT) || (data_type == VTK_INT) || (data_type == VTK_LONG) ||
    (data_type == VTK_ID_TYPE) || (data_type == VTK_LONG_LONG) || (data_type == VTK_TYPE_INT64);
}

//----------------------------------------------------------------------------
bool IsUnsignedIntegralType(int data_type)
{
  constexpr bool is_char_type_signed = (CHAR_MIN == SCHAR_MIN) && (CHAR_MAX == SCHAR_MAX);

  return (!is_char_type_signed && (data_type == VTK_CHAR)) || (data_type == VTK_UNSIGNED_CHAR) ||
    (data_type == VTK_UNSIGNED_SHORT) || (data_type == VTK_UNSIGNED_INT) ||
    (data_type == VTK_UNSIGNED_LONG) || (data_type == VTK_ID_TYPE) ||
    (data_type == VTK_UNSIGNED_LONG_LONG);
}

//----------------------------------------------------------------------------
bool IsFloatType(int data_type)
{
  return ((data_type == VTK_FLOAT) || (data_type == VTK_DOUBLE));
}

//----------------------------------------------------------------------------
bool ConvertDataArrayToMCArray(
  vtkDataArray* data_array, int offset, int stride, conduit_cpp::Node& conduit_node)
{
  stride = std::max(stride, 1);
  conduit_index_t number_of_elements = data_array->GetNumberOfValues() / stride;

  int data_type = data_array->GetDataType();
  int data_type_size = data_array->GetDataTypeSize();
  int array_type = data_array->GetArrayType();

  if (array_type != vtkAbstractArray::AoSDataArrayTemplate)
  {
    vtkLog(ERROR, "Unsupported data array type: " << data_array->GetDataTypeAsString());
    return false;
  }

  // The code below uses the legacy GetVoidPointer on purpose to get zero copy.
  bool is_supported = true;
  if (IsSignedIntegralType(data_type))
  {
    switch (data_type_size)
    {
      case 1:
        conduit_node.set_external_int8_ptr((conduit_int8*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_int8), stride * sizeof(conduit_int8));
        break;

      case 2:
        conduit_node.set_external_int16_ptr((conduit_int16*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_int16), stride * sizeof(conduit_int16));
        break;

      case 4:
        conduit_node.set_external_int32_ptr((conduit_int32*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_int32), stride * sizeof(conduit_int32));
        break;

      case 8:
        conduit_node.set_external_int64_ptr((conduit_int64*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_int64), stride * sizeof(conduit_int64));
        break;

      default:
        is_supported = false;
    }
  }
  else if (IsUnsignedIntegralType(data_type))
  {
    switch (data_type_size)
    {
      case 1:
        conduit_node.set_external_uint8_ptr((conduit_uint8*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_uint8), stride * sizeof(conduit_uint8));
        break;

      case 2:
        conduit_node.set_external_uint16_ptr((conduit_uint16*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_uint16), stride * sizeof(conduit_uint16));
        break;

      case 4:
        conduit_node.set_external_uint32_ptr((conduit_uint32*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_uint32), stride * sizeof(conduit_uint32));
        break;

      case 8:
        conduit_node.set_external_uint64_ptr((conduit_uint64*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_uint64), stride * sizeof(conduit_uint64));
        break;

      default:
        is_supported = false;
    }
  }
  else if (IsFloatType(data_type))
  {
    switch (data_type_size)
    {
      case 4:
        conduit_node.set_external_float32_ptr((conduit_float32*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_float32), stride * sizeof(conduit_float32));
        break;

      case 8:
        conduit_node.set_external_float64_ptr((conduit_float64*)data_array->GetVoidPointer(0),
          number_of_elements, offset * sizeof(conduit_float64), stride * sizeof(conduit_float64));
        break;

      default:
        is_supported = false;
    }
  }

  if (!is_supported)
  {
    vtkLog(ERROR,
      "Unsupported data array type: " << data_array->GetDataTypeAsString()
                                      << " size: " << data_type_size << " type: " << array_type);
  }

  return is_supported;
}

//----------------------------------------------------------------------------
bool ConvertDataArrayToMCArray(vtkDataArray* data_array, conduit_cpp::Node& conduit_node)
{
  return ConvertDataArrayToMCArray(data_array, 0, 0, conduit_node);
}

//----------------------------------------------------------------------------
bool ConvertPoints(vtkPoints* points, conduit_cpp::Node& x_values_node,
  conduit_cpp::Node& y_values_node, conduit_cpp::Node& z_values_node)
{
  if (auto data_array = points->GetData())
  {
    return ConvertDataArrayToMCArray(data_array, 0, 3, x_values_node) &&
      ConvertDataArrayToMCArray(data_array, 1, 3, y_values_node) &&
      ConvertDataArrayToMCArray(data_array, 2, 3, z_values_node);
  }

  return false;
}

//----------------------------------------------------------------------------
bool FillTopology(vtkDataSet* data_set, conduit_cpp::Node& conduit_node)
{
  if (auto imageData = vtkImageData::SafeDownCast(data_set))
  {
    auto coords_node = conduit_node["coordsets/coords"];

    coords_node["type"] = "uniform";

    int* dimensions = imageData->GetDimensions();
    coords_node["dims/i"] = dimensions[0];
    coords_node["dims/j"] = dimensions[1];
    coords_node["dims/k"] = dimensions[2];

    double* origin = imageData->GetOrigin();
    coords_node["origin/x"] = origin[0];
    coords_node["origin/y"] = origin[1];
    coords_node["origin/z"] = origin[2];

    double* spacing = imageData->GetSpacing();
    coords_node["spacing/dx"] = spacing[0];
    coords_node["spacing/dy"] = spacing[1];
    coords_node["spacing/dz"] = spacing[2];

    auto topologies_node = conduit_node["topologies/mesh"];
    topologies_node["type"] = "uniform";
    topologies_node["coordset"] = "coords";
  }
  else if (auto rectilinear_grid = vtkRectilinearGrid::SafeDownCast(data_set))
  {
    auto coords_node = conduit_node["coordsets/coords"];

    coords_node["type"] = "rectilinear";

    auto x_values_node = coords_node["values/x"];
    if (!ConvertDataArrayToMCArray(rectilinear_grid->GetXCoordinates(), x_values_node))
    {
      vtkLog(ERROR, "Failed ConvertDataArrayToMCArray for values/x");
      return false;
    }

    auto y_values_node = coords_node["values/y"];
    if (!ConvertDataArrayToMCArray(rectilinear_grid->GetYCoordinates(), y_values_node))
    {
      vtkLog(ERROR, "Failed ConvertDataArrayToMCArray for values/y");
      return false;
    }

    auto z_values_node = coords_node["values/z"];
    if (!ConvertDataArrayToMCArray(rectilinear_grid->GetZCoordinates(), z_values_node))
    {
      vtkLog(ERROR, "Failed ConvertDataArrayToMCArray for values/z");
      return false;
    }

    auto topologies_node = conduit_node["topologies/mesh"];
    topologies_node["type"] = "rectilinear";
    topologies_node["coordset"] = "coords";
  }
  else if (auto structured_grid = vtkStructuredGrid::SafeDownCast(data_set))
  {
    auto coords_node = conduit_node["coordsets/coords"];

    coords_node["type"] = "explicit";

    auto x_values_node = coords_node["values/x"];
    auto y_values_node = coords_node["values/y"];
    auto z_values_node = coords_node["values/z"];

    if (!ConvertPoints(structured_grid->GetPoints(), x_values_node, y_values_node, z_values_node))
    {
      vtkLog(ERROR, "Failed ConvertPoints for structured grid");
      return false;
    }

    auto topologies_node = conduit_node["topologies/mesh"];
    topologies_node["type"] = "structured";
    topologies_node["coordset"] = "coords";
    int* dimensions = structured_grid->GetDimensions();
    topologies_node["elements/dims/i"] = dimensions[0];
    topologies_node["elements/dims/j"] = dimensions[1];
    topologies_node["elements/dims/k"] = dimensions[2];
  }
  else if (auto unstructured_grid = vtkUnstructuredGrid::SafeDownCast(data_set))
  {
    if (IsMixedShape(unstructured_grid))
    {
      vtkLogF(ERROR, "Unstructured type with mixed shape type unsupported.");
      return false;
    }

    auto coords_node = conduit_node["coordsets/coords"];

    coords_node["type"] = "explicit";

    auto x_values_node = coords_node["values/x"];
    auto y_values_node = coords_node["values/y"];
    auto z_values_node = coords_node["values/z"];

    auto* points = unstructured_grid->GetPoints();

    if (points)
    {
      if (!ConvertPoints(points, x_values_node, y_values_node, z_values_node))
      {
        vtkLogF(ERROR, "ConvertPoints failed for unstructured grid.");
        return false;
      }
    }
    else
    {
      x_values_node = std::vector<float>();
      y_values_node = std::vector<float>();
      z_values_node = std::vector<float>();
    }

    auto topologies_node = conduit_node["topologies/mesh"];
    topologies_node["type"] = "unstructured";
    topologies_node["coordset"] = "coords";

    int cell_type = VTK_VERTEX;
    const auto number_of_cells = unstructured_grid->GetNumberOfCells();
    if (number_of_cells > 0)
    {
      cell_type = unstructured_grid->GetCellType(0);
    }

    switch (cell_type)
    {
      case VTK_HEXAHEDRON:
        topologies_node["elements/shape"] = "hex";
        break;
      case VTK_TETRA:
        topologies_node["elements/shape"] = "tet";
        break;
      case VTK_QUAD:
        topologies_node["elements/shape"] = "quad";
        break;
      case VTK_TRIANGLE:
        topologies_node["elements/shape"] = "tri";
        break;
      case VTK_LINE:
        topologies_node["elements/shape"] = "line";
        break;
      case VTK_VERTEX:
        topologies_node["elements/shape"] = "point";
        break;
      default:
        vtkLog(ERROR, << "Unsupported cell type in unstructured grid. Cell type: "
                      << vtkCellTypes::GetClassNameFromTypeId(cell_type));
        return false;
    }

    auto cell_connectivity = unstructured_grid->GetCells();
    auto connectivity_node = topologies_node["elements/connectivity"];

    if (!ConvertDataArrayToMCArray(cell_connectivity->GetConnectivityArray(), connectivity_node))
    {
      vtkLogF(ERROR, "ConvertDataArrayToMCArray failed for unstructured grid.");
      return false;
    }
  }
  else
  {
    vtkLog(ERROR, "Unsupported data set type: " << data_set->GetClassName());
    return false;
  }

  return true;
}

//----------------------------------------------------------------------------
bool FillFields(
  vtkFieldData* field_data, const std::string& association, conduit_cpp::Node& conduit_node)
{
  bool is_success = true;

  int array_count = field_data->GetNumberOfArrays();
  for (int array_index = 0; is_success && array_index < array_count; ++array_index)
  {
    auto array = field_data->GetArray(array_index);
    auto name = array->GetName();
    if (!name)
    {
      vtkLogF(WARNING, "Unamed array, it will be ignored.");
      continue;
    }

    auto field_node = conduit_node["fields"][name];
    field_node["association"] = association;
    field_node["topology"] = "mesh";
    field_node["volume_dependent"] = "false";

    auto values_node = field_node["values"];
    is_success = ConvertDataArrayToMCArray(array, values_node);
  }

  return is_success;
}

//----------------------------------------------------------------------------
bool FillFields(vtkDataSet* data_set, conduit_cpp::Node& conduit_node)
{
  if (auto cell_data = data_set->GetCellData())
  {
    if (!FillFields(cell_data, "element", conduit_node))
    {
      vtkVLog(vtkLogger::VERBOSITY_ERROR, "FillFields with element failed.");
      return false;
    }
  }

  if (auto point_data = data_set->GetPointData())
  {
    if (!FillFields(point_data, "vertex", conduit_node))
    {
      vtkVLog(vtkLogger::VERBOSITY_ERROR, "FillFields with vertex failed.");
      return false;
    }
  }

  if (auto field_data = data_set->GetFieldData())
  {
    if (field_data->GetNumberOfArrays() > 0)
    {
      vtkVLog(vtkLogger::VERBOSITY_WARNING,
        "Field without associated topology is not supported by conduit. Will be ignored.");
    }
  }

  return true;
}

//----------------------------------------------------------------------------
bool FillConduitNodeFromDataSet(vtkDataSet* data_set, conduit_cpp::Node& conduit_node)
{
  return FillTopology(data_set, conduit_node) && FillFields(data_set, conduit_node);
}

} // anonymous namespace

namespace vtkDataObjectToConduit
{

//----------------------------------------------------------------------------
bool FillConduitNode(vtkDataObject* data_object, conduit_cpp::Node& conduit_node)
{
  auto data_set = vtkDataSet::SafeDownCast(data_object);
  if (!data_set)
  {
    vtkLogF(ERROR, "Only Data Set objects are supported in vtkDataObjectToConduit.");
    return false;
  }

  return FillConduitNodeFromDataSet(data_set, conduit_node);
}

} // vtkDataObjectToConduit namespace
