/*
 * Distributed under the OSI-approved Apache License, Version 2.0.  See
 * accompanying file Copyright.txt for details.
 *
 * HDF5ReaderP.cpp
 *
 *  Created on: March 20, 2017
 *      Author: Junmin
 */

#include "HDF5ReaderP.h"

#include "adios2/ADIOSMPI.h"

namespace adios
{

HDF5Reader::HDF5Reader(ADIOS &adios, const std::string name,
                       const std::string accessMode, MPI_Comm mpiComm,
                       const Method &method)
: Engine(adios, "HDF5Reader", name, accessMode, mpiComm,
         method, 
         " HDF5Reader constructor (or call to ADIOS Open).\n")
{
  Init();
  MPI_Comm_rank(mpiComm, &_mpi_rank);
  MPI_Comm_size(mpiComm, &_mpi_size);

}

HDF5Reader::~HDF5Reader() {}

void HDF5Reader::Init()
{
  if (m_AccessMode != "r" && m_AccessMode != "read")
    {
        throw std::invalid_argument(
            "ERROR: HDF5Reader doesn't support access mode " + m_AccessMode +
            ", in call to ADIOS Open or HDF5Reader constructor\n");
    }

    _H5File.H5_Init(m_Name, m_MPIComm, false);
    _H5File.GetNumTimeSteps();
}


Variable<void> * HDF5Reader::InquireVariable(const std::string &variableName,
					     const bool readIn )
{
  std::cout<<"Not implemented: HDF5Reder::InquireVariable()"<<std::endl;
}

Variable<char> * HDF5Reader::InquireVariableChar(const std::string &variableName,
						 const bool readIn )
{}

Variable<unsigned char> * HDF5Reader::InquireVariableUChar(const std::string &variableName,
							     const bool readIn )
{}

Variable<short> * HDF5Reader::InquireVariableShort(const std::string &variableName,
						   const bool readIn )
{}

Variable<unsigned short> * HDF5Reader::InquireVariableUShort(const std::string &variableName,
							       const bool readIn)
{}



Variable<int> *HDF5Reader::InquireVariableInt(const std::string &variableName,
					      const bool)
{}

Variable<unsigned int> *HDF5Reader::InquireVariableUInt(const std::string &variableName,
							const bool)
{}

Variable<long int> *HDF5Reader::InquireVariableLInt(const std::string &variableName,
						    const bool)
{}

Variable<unsigned long int> *
HDF5Reader::InquireVariableULInt(const std::string &variableName,
				 const bool)
{}

Variable<long long int> *
HDF5Reader::InquireVariableLLInt(const std::string &variableName,
				 const bool)
{}

Variable<unsigned long long int> * 
HDF5Reader::InquireVariableULLInt(const std::string &variableName,
				  const bool)
{}

Variable<float> *HDF5Reader::InquireVariableFloat(const std::string &variableName,
						  const bool)
{}

Variable<double> *HDF5Reader::InquireVariableDouble(const std::string &variableName,
						    const bool)
{
 
  if (_mpi_rank == 0) {
    std::cout<<" ... reading var: "<<variableName<<std::endl;
  }
  int totalts = _H5File.GetNumTimeSteps();

  if (_mpi_rank == 0) {
    std::cout<<" ... I saw total timesteps: "<<totalts<<std::endl;
  }

  while (true) {    
    double values[1];
    UseHDFRead(variableName, values, H5T_NATIVE_DOUBLE);    
    Variable<double> v = m_ADIOS.DefineVariable<double>("junk", adios::Dims{8});
    ReadMe(v, values, H5T_NATIVE_DOUBLE);    
    if (_H5File._currentTimeStep >= totalts-1) {
      break;
    }
    _H5File.H5_Advance(totalts);    
  }
}

Variable<long double> * HDF5Reader::InquireVariableLDouble(const std::string &variableName,
							   const bool)
{}

Variable<std::complex<float>> * HDF5Reader::InquireVariableCFloat(const std::string &variableName,
								  const bool)
{}

Variable<std::complex<double>> * HDF5Reader::InquireVariableCDouble(const std::string &variableName,
				   const bool)
{}

Variable<std::complex<long double>>* HDF5Reader::InquireVariableCLDouble(const std::string &variableName,
									     const bool)
{}

VariableCompound * HDF5Reader::InquireVariableCompound(const std::string &variableName,
						       const bool readIn)
{}

template <class T>
void HDF5Reader::ReadMe(Variable<T> variable, T *data_array, hid_t h5type)
{
  hid_t datasetID = H5Dopen(_H5File._group_id, variable.m_Name.c_str(), H5P_DEFAULT);

  if (_mpi_rank == 0) {
    std::cout<<" hdf5 reading variable: "<<variable.m_Name<<" timestep: "<<_H5File._currentTimeStep<<std::endl;
  }
  
  if (datasetID < 0) {
    return;
  }

  hid_t filespace = H5Dget_space(datasetID);

  if (filespace < 0) {
    return;
  }

  int ndims = variable.m_GlobalDimensions.size();
  std::vector<hsize_t> count, offset, stride;

  int elementsRead = 1;
  for (int i = 0; i < ndims; i++)
    {
      count.push_back(variable.m_LocalDimensions[i]);
      offset.push_back(variable.m_Offsets[i]);
      stride.push_back(1);
      elementsRead *= variable.m_LocalDimensions[i];
    }

  hid_t ret=H5Sselect_hyperslab(filespace, H5S_SELECT_SET, offset.data(), stride.data(), count.data(), NULL);			  
  if (ret < 0) {
    return;
  }

  hid_t mem_dataspace = H5Screate_simple (ndims, count.data(), NULL);

  //T  data_array[elementsRead];
  ret = H5Dread(datasetID, h5type, mem_dataspace, filespace, H5P_DEFAULT, data_array);

  for (int i=0; i<elementsRead; i++) {
    std::cout<<"... ts "<<_H5File._currentTimeStep<<", "<<data_array[i]<<std::endl;
  }

  H5Sclose(mem_dataspace);

  H5Sclose(filespace);
  H5Dclose(datasetID);  
}


  
template<class T>
void HDF5Reader::UseHDFRead(const std::string& variableName, T* values, hid_t h5type)
{
  hid_t datasetID = H5Dopen(_H5File._group_id, variableName.c_str(), H5P_DEFAULT);
  if (_mpi_rank == 0) {
    std::cout<<" opened to read: "<<variableName<<std::endl;
  }
  
  if (datasetID < 0) {
    return;
  }
  hid_t filespace = H5Dget_space(datasetID);

  if (filespace < 0) {
    return;
  }
  int ndims      = H5Sget_simple_extent_ndims(filespace);
  hsize_t dims[ndims];
  herr_t status_n  = H5Sget_simple_extent_dims(filespace, dims, NULL);

  hsize_t start[ndims]={0}, count[ndims]={0}, stride[ndims]={1};

  int totalElements = 1;
  for (int i=0; i<ndims; i++) {
    std::cout<<" ["<<i<<"] th dimension: "<<dims[i]<<std::endl;
    count[i] = dims[i];
    totalElements *= dims[i];
  }
  
  start[0] = _mpi_rank * dims[0]/_mpi_size;
  count[0] = dims[0]/_mpi_size;
  if (_mpi_rank ==  _mpi_size -1) {
    count[0] = dims[0] - count[0]*(_mpi_size - 1);
    std::cout<<" rank = "<<_mpi_rank<<", count="<<count[0]<<std::endl;
  }

  hid_t ret=H5Sselect_hyperslab(filespace, H5S_SELECT_SET, start, stride, count, NULL);			  
  if (ret < 0) {
    return;
  }

  hid_t mem_dataspace = H5Screate_simple (ndims, count, NULL);

  int elementsRead = 1; 
  for (int i=0; i<ndims; i++) {
    elementsRead *= count[i];
  }

  T  data_array[elementsRead];
  ret = H5Dread(datasetID, h5type, mem_dataspace, filespace, H5P_DEFAULT, data_array);

  for (int i=0; i<elementsRead; i++) {
    std::cout<<"... rank "<<_mpi_rank<<"   , "<<data_array[i]<<std::endl;
  }

  H5Sclose(mem_dataspace);

  H5Sclose(filespace);
  H5Dclose(datasetID);
}
  

void HDF5Reader::Advance(float timeout_sec)
{
  int totalts = _H5File.GetNumTimeSteps();
  _H5File.H5_Advance(totalts);
}

void HDF5Reader::Close(const int transportIndex)
{
    _H5File.H5_Close();
}

} // end namespace adios