// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause

#include "vtkCellGridReader.h"

#include "vtkCellAttribute.h"
#include "vtkCellGridIOQuery.h"
#include "vtkCellMetadata.h"
#include "vtkDataArray.h"
#include "vtkDataSetAttributes.h"
#include "vtkFiltersCellGrid.h"
#include "vtkIOCellGrid.h"
#include "vtkObjectFactory.h"
#include "vtkStringToken.h"

#include <array>
#include <sstream>

namespace
{

int ArrayTypeToEnum(const std::string& arrayType)
{
  int result = -1;
  if (arrayType == "int")
  {
    result = VTK_INT;
  }
  else if (arrayType == "vtktypeuint8")
  {
    result = VTK_TYPE_UINT8;
  }
  else if (arrayType == "vtktypeint8")
  {
    result = VTK_TYPE_INT8;
  }
  else if (arrayType == "vtktypeuint16")
  {
    result = VTK_TYPE_UINT16;
  }
  else if (arrayType == "vtktypeint16")
  {
    result = VTK_TYPE_INT16;
  }
  else if (arrayType == "vtktypeuint32")
  {
    result = VTK_TYPE_UINT32;
  }
  else if (arrayType == "vtktypeint32")
  {
    result = VTK_TYPE_INT32;
  }
  else if (arrayType == "vtktypeuint64")
  {
    result = VTK_TYPE_UINT64;
  }
  else if (arrayType == "vtktypeint64")
  {
    result = VTK_TYPE_INT64;
  }
  else if (arrayType == "double")
  {
    result = VTK_DOUBLE;
  }
  else if (arrayType == "float")
  {
    result = VTK_FLOAT;
  }
  return result;
}

template <typename T>
void AppendArrayData(T* data, const nlohmann::json& values)
{
  auto valueVector = values.get<std::vector<T>>();
  vtkIdType ii = 0;
  for (const auto& value : valueVector)
  {
    data[ii] = value;
    ++ii;
  }
}

void addCachedRange(vtkCellGridRangeQuery::CacheMap& rangeCache, vtkCellAttribute* attribute,
  const nlohmann::json& rangeInfo)
{
  auto& ranges(rangeCache[attribute]);
  int nc = attribute->GetNumberOfComponents();
  ranges.resize(nc + 2);
  for (const auto& entry : rangeInfo.items())
  {
    int comp;
    if (entry.key() == "L₁")
    {
      comp = 1;
    }
    else if (entry.key() == "L₂")
    {
      comp = 0;
    }
    else
    {
      comp = std::stoi(entry.key()) + 2;
      if (comp < 2 || comp > attribute->GetNumberOfComponents() + 2)
      {
        vtkWarningWithObjectMacro(attribute,
          "Range for unexpected component " << (comp - 2) << " of " << attribute->GetName().Data()
                                            << ".");
        comp = 0;
      }
    }
    ranges[comp].FiniteRange[0] = entry.value().at("min");
    ranges[comp].FiniteRange[1] = entry.value().at("max");
    ranges[comp].FiniteRangeTime.Modified();
    ranges[comp].EntireRangeTime = vtkTimeStamp();
  }
}

} // anonymous namespace

VTK_ABI_NAMESPACE_BEGIN
vtkStandardNewMacro(vtkCellGridReader);

vtkCellGridReader::vtkCellGridReader()
{
  this->SetNumberOfInputPorts(0);
  vtkFiltersCellGrid::RegisterCellsAndResponders();
  vtkIOCellGrid::RegisterCellsAndResponders();
}

vtkCellGridReader::~vtkCellGridReader()
{
  this->SetFileName(nullptr);
}

void vtkCellGridReader::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os, indent);
  os << indent << "FileName: \"" << (this->FileName ? this->FileName : "(none)") << "\"\n";
}

int vtkCellGridReader::RequestInformation(
  vtkInformation* request, vtkInformationVector** inputVector, vtkInformationVector* outputVector)
{
  if (!this->Superclass::RequestInformation(request, inputVector, outputVector))
  {
    return 0;
  }

  // Read file metadata
  // Make sure we have a file to read.
  if (!this->FileName)
  {
    vtkErrorMacro("A FileName must be specified.");
    return 0;
  }

  std::string fileNameAsString(this->FileName);

  if (fileNameAsString.find('\\') != std::string::npos)
  {
    vtksys::SystemTools::ConvertToUnixSlashes(fileNameAsString);
  }

  if (!vtksys::SystemTools::FileIsFullPath(fileNameAsString))
  {
    fileNameAsString = vtksys::SystemTools::CollapseFullPath(fileNameAsString);
  }

  if (this->FileName != fileNameAsString)
  {
    this->SetFileName(fileNameAsString.c_str());
  }

  // TODO: Load metadata if not done previously
  //       Add this info to the output vtkInformation
  // vtkInformation* info = outputVector->GetInformationObject(0);
  // info->Append(vtkStreamingDemandDrivenPipeline::TIME_STEPS(), i * period);
  // info->Set(vtkStreamingDemandDrivenPipeline::TIME_RANGE(), timeRange.data(), 2);
  return 1;
}

bool vtkCellGridReader::FromJSON(const nlohmann::json& jj, vtkCellGrid* output)
{
  auto jtype = jj.find("data-type");
  if (jtype == jj.end() || jtype->get<std::string>() != "cell-grid")
  {
    vtkErrorMacro("Data type is missing or incorrect.");
    return false;
  }

  auto jArrayGroup = jj.find("arrays");
  if (jArrayGroup == jj.end() || !jArrayGroup->is_object())
  {
    vtkErrorMacro("Missing arrays section.");
    return false;
  }

  auto jAttributes = jj.find("attributes");
  if (jAttributes == jj.end() || !jAttributes->is_array())
  {
    vtkErrorMacro("Missing attributes section.");
    return false;
  }

  auto jCellTypes = jj.find("cell-types");
  if (jCellTypes == jj.end() || !jCellTypes->is_array())
  {
    vtkErrorMacro("Missing cell-types section.");
    return false;
  }

  bool skipVersionChecks = false;
  auto jSchemaName = jj.find("schema-name");
  auto jSchemaVersion = jj.find("schema-version");
  if (jSchemaName == jj.end() || jSchemaVersion == jj.end())
  {
    vtkWarningMacro("No schema name and version provided. Skipping version checks.");
    skipVersionChecks = true;
  }
  if (!skipVersionChecks)
  {
    auto jFormatVersion = jj.find("format-version");
    if (jFormatVersion == jj.end() || jFormatVersion->get<std::uint32_t>() > 1)
    {
      vtkErrorMacro("File format version missing or newer than reader code.");
      return false;
    }
    if (jSchemaName->get<std::string>() != "dg leaf")
    {
      vtkErrorMacro("Expecting a schema name of 'dg leaf'.");
      return false;
    }
    if (jSchemaVersion->get<std::uint32_t>() > 1)
    {
      vtkErrorMacro("Cannot read a schema newer than v1.");
      return false;
    }
    output->SetSchema(jSchemaName->get<std::string>(), jSchemaVersion->get<std::uint32_t>());
  }

  std::uint32_t contentVersion = 0;
  auto jContentVersion = jj.find("content-version");
  if (jContentVersion != jj.end())
  {
    contentVersion = jContentVersion->get<std::uint32_t>();
    output->SetContentVersion(contentVersion);
  }

  output->Initialize();

  for (const auto& jGroupEntry : jArrayGroup->items())
  {
    if (!jGroupEntry.value().is_array())
    {
      vtkWarningMacro("Skipping " << jGroupEntry.key());
      continue;
    }
    auto* arrayGroup = output->GetAttributes(vtkStringToken(jGroupEntry.key()).GetId());
    for (const auto& jArrayEntry : jGroupEntry.value().items())
    {
      auto arrayName = jArrayEntry.value()["name"].get<std::string>();
      auto arrayType = jArrayEntry.value()["type"].get<std::string>();
      auto arrayComps = jArrayEntry.value()["components"].get<int>();
      auto arrayTuples = jArrayEntry.value()["tuples"].get<vtkIdType>();
      auto* array = vtkDataArray::CreateDataArray(ArrayTypeToEnum(arrayType));
      array->SetNumberOfComponents(arrayComps);
      array->SetNumberOfTuples(arrayTuples);
      array->SetName(arrayName.c_str());
      switch (array->GetDataType())
      {
        vtkTemplateMacro(AppendArrayData(
          static_cast<VTK_TT*>(array->GetVoidPointer(0)), jArrayEntry.value()["data"]));
      }
      arrayGroup->AddArray(array);
      array->FastDelete();
      auto arrayIsScalars = jArrayEntry.value().find("default_scalars");
      if (arrayIsScalars != jArrayEntry.value().end() && arrayIsScalars->get<bool>())
      {
        arrayGroup->SetScalars(array);
      }
      auto arrayIsVec = jArrayEntry.value().find("default_vectors");
      if (arrayIsVec != jArrayEntry.value().end() && arrayIsVec->get<bool>())
      {
        arrayGroup->SetVectors(array);
      }
    }
  }

  for (const auto& jCellTypeEntry : *jCellTypes)
  {
    if (!jCellTypeEntry.is_object() || jCellTypeEntry.find("type") == jCellTypeEntry.end())
    {
      vtkWarningMacro("Skipping a malformed cell-type entry." << jCellTypeEntry.dump(2));
      continue;
    }
    auto cellType = vtkStringToken(jCellTypeEntry["type"].get<std::string>());
    auto cell = vtkCellMetadata::NewInstance(cellType, output);
    (void)cell;
  }

  std::vector<vtkCellAttribute*> attributeList;
  for (const auto& jAttribute : *jAttributes)
  {
    if (!jAttribute.is_object() || jAttribute.find("name") == jAttribute.end() ||
      jAttribute.find("space") == jAttribute.end() ||
      jAttribute.find("components") == jAttribute.end() ||
      jAttribute.find("cell-info") == jAttribute.end())
    {
      vtkWarningMacro("Skipping malformed cell-attribute entry. " << jAttribute.dump(2));
      continue;
    }
    auto attributeName = vtkStringToken(jAttribute["name"].get<std::string>());
    auto attributeSpace = vtkStringToken(jAttribute["space"].get<std::string>());
    auto shapeIt = jAttribute.find("shape");
    bool attributeIsShape = !(shapeIt == jAttribute.end() || !shapeIt->get<bool>());
    auto attributeComps = jAttribute["components"].get<int>();
    vtkNew<vtkCellAttribute> attribute;
    attribute->Initialize(attributeName, attributeSpace, attributeComps);
    attributeList.push_back(attribute);
    output->AddCellAttribute(attribute);
    if (attributeIsShape)
    {
      output->SetShapeAttribute(attribute);
    }
    auto rangeIt = jAttribute.find("range");
    if (rangeIt != jAttribute.end())
    {
      addCachedRange(output->GetRangeCache(), attribute, *rangeIt);
    }
  }

  // Finally, although we have created vtkCellMetadata objects per the JSON,
  // we have not configured them. Now that the arrays and attributes are
  // present, use a query/responder to do so.
  this->Query->PrepareToDeserialize(*jCellTypes, *jAttributes, attributeList);
  if (!output->Query(this->Query))
  {
    return false;
  }

  return true;
}

int vtkCellGridReader::RequestData(
  vtkInformation*, vtkInformationVector**, vtkInformationVector* outputVector)
{
  // Get the output
  vtkCellGrid* output = vtkCellGrid::GetData(outputVector);

  // Make sure we have a file to read.
  if (!this->FileName)
  {
    vtkErrorMacro("A FileName must be specified.");
    return 0;
  }

  // Check the file's validity.
  std::ifstream file(this->FileName);
  if (!file.good())
  {
    vtkErrorMacro("Cannot read file \"" << this->FileName << "\".");
    return 0;
  }

  nlohmann::json jj;
  if (file.peek() == '{')
  {
    // Read the file into nlohmann json.
    try
    {
      jj = nlohmann::json::parse(file);
    }
    catch (...)
    {
      vtkErrorMacro("Cannot parse file \"" << this->FileName << "\".");
      return 0;
    }
  }
  else
  {
    std::string datatype;
    std::string format;
    std::string version;
    file >> datatype;
    file >> format;
    file >> version;
    if (!file.good() || datatype != "vtkCellGrid" || format != "MessagePack" || version != "v1")
    {
      vtkErrorMacro("Cannot parse binary header of \"" << this->FileName << "\","
                                                       << " type " << datatype << " format "
                                                       << format << " version " << version << ".");
      return 0;
    }
    file.get(); // Skip the newline character after the version number.

    // Compute the remaining size of the file that holds message-pack data.
    auto start = file.tellg();
    file.seekg(0, std::ios::end);
    auto end = file.tellg();
    file.seekg(start, std::ios::beg);
    // Use 'char' instead of 'uint8_t' to avoid the following clang >= 19 error:
    // "implicit instantiation of undefined template 'std::char_traits<unsigned char>'"
    std::vector<char> data;
    data.resize(end - start);
    auto readSize = data.size() / sizeof(std::istream::char_type) +
      (data.size() % sizeof(std::istream::char_type) ? 1 : 0);
    file.read(reinterpret_cast<std::istream::char_type*>(data.data()), readSize);
    try
    {
      // The final "false" below allows the data to not be fully consumed,
      // which may happen if sizeof(istream::char_type) > 1. In the future,
      // it may also happen that a file contains multiple JSON streams.
      jj = nlohmann::json::from_msgpack(data.begin(), data.end(), false);
    }
    catch (...)
    {
      vtkErrorMacro("Cannot parse MessagePack data of \""
        << this->FileName << "\","
        << " type " << datatype << " format " << format << " version " << version << ".");
      return 0;
    }
  }

  bool status = this->FromJSON(jj, output);
  return status ? 1 : 0;
}
VTK_ABI_NAMESPACE_END
