/*******************************************************************************
 *
 * TRIQS: a Toolbox for Research in Interacting Quantum Systems
 *
 * Copyright (C) 2011-2014 by O. Parcollet
 *
 * TRIQS is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * TRIQS. If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/
#include "./base.hpp"

namespace triqs {
namespace h5 {

 //------------------------------------------------

 // dataspace from lengths and strides. Correct for the complex. strides must be >0
 dataspace dataspace_from_LS(int R, bool is_complex, hsize_t const *Ltot, hsize_t const *L, hsize_t const *S,
                             hsize_t const *offset) {
  int rank = R + (is_complex ? 1 : 0);
  hsize_t totdimsf[rank], dimsf[rank], stridesf[rank], offsetf[rank]; // dataset dimensions
  for (size_t u = 0; u < R; ++u) {
   offsetf[u] = (offset ? offset[u] : 0);
   dimsf[u] = L[u];
   totdimsf[u] = Ltot[u];
   stridesf[u] = S[u];
  }
  if (is_complex) {
   offsetf[rank - 1] = 0;
   dimsf[rank - 1] = 2;
   totdimsf[rank - 1] = 2;
   stridesf[rank - 1] = 1;
  }

  dataspace ds = H5Screate_simple(rank, totdimsf, NULL);
  if (!ds.is_valid()) TRIQS_RUNTIME_ERROR << "Cannot create the dataset";

  herr_t err = H5Sselect_hyperslab(ds, H5S_SELECT_SET, offsetf, stridesf, dimsf, NULL);
  if (err < 0) TRIQS_RUNTIME_ERROR << "Cannot set hyperslab";

  return ds;
 }

 /****************** Write string attribute *********************************************/

 void write_string_attribute(hid_t id, std::string name, std::string value) {

  datatype strdatatype = H5Tcopy(H5T_C_S1);
  auto status = H5Tset_size(strdatatype, value.size() + 1);
  // auto status = H5Tset_size(strdatatype, H5T_VARIABLE);
  if (status < 0) TRIQS_RUNTIME_ERROR << "Internal error in H5Tset_size";

  dataspace space = H5Screate(H5S_SCALAR);

  attribute attr = H5Acreate2(id, name.c_str(), strdatatype, space, H5P_DEFAULT, H5P_DEFAULT);
  if (!attr.is_valid()) TRIQS_RUNTIME_ERROR << "Cannot create the attribute " << name;

  status = H5Awrite(attr, strdatatype, (void *)(value.c_str()));
  if (status < 0) TRIQS_RUNTIME_ERROR << "Cannot write the attribute " << name;
 }


 /****************** Read string attribute *********************************************/

 /// Return the attribute name of obj, and "" if the attribute does not exist.
 std::string read_string_attribute(hid_t id, std::string name) {

  // if the attribute is not present, return 0
  if (H5LTfind_attribute(id, name.c_str()) == 0) return ""; // not present

  attribute attr = H5Aopen(id, name.c_str(), H5P_DEFAULT);
  if (!attr.is_valid()) TRIQS_RUNTIME_ERROR << "Cannot open the attribute " << name;

  dataspace space = H5Aget_space(attr);

  int rank = H5Sget_simple_extent_ndims(space);
  if (rank != 0) TRIQS_RUNTIME_ERROR << "Reading a string attribute and got rank !=0";

  datatype strdatatype = H5Aget_type(attr);

  std::vector<char> buf(H5Aget_storage_size(attr) + 1, 0x00);
  auto err = H5Aread(attr, strdatatype, (void *)(&buf[0]));
  if (err < 0) TRIQS_RUNTIME_ERROR << "Cannot read the attribute " << name;

  std::string ret = "";
  ret.append(&(buf.front()));
  return ret;
 }
}
}