#include "./group.hpp"
#include "./base.hpp"

namespace triqs {
namespace h5 {

 group::group(h5::file f) : h5_object() {
  id = H5Gopen2(f, "/", H5P_DEFAULT);
  if (id < 0) TRIQS_RUNTIME_ERROR << "Can not open the root group / in the file " << f.name();
 }

 group::group(h5_object obj) : h5_object(std::move(obj)) {
  if (!H5Iis_valid(this->id)) TRIQS_RUNTIME_ERROR << "Invalid input in group constructor from id";
  if (H5Iget_type(this->id) != H5I_GROUP) TRIQS_RUNTIME_ERROR << "Group constructor must take the id of a group or a file ";
 }

 group::group(hid_t id_) : group(h5_object(id_)){}

 void group::_write_triqs_hdf5_data_scheme(const char *a) { h5::write_string_attribute(id, "TRIQS_HDF5_data_scheme", a); }

 std::string group::read_triqs_hdf5_data_scheme() const { return read_string_attribute(id, "TRIQS_HDF5_data_scheme"); }

 std::string group::name() const {
  char _n[1];
  ssize_t size = H5Iget_name(id, _n, 1); // first call, get the size only
  std::vector<char> buf(size + 1, 0x00);
  H5Iget_name(id, buf.data(), 1); // now get the name
  std::string res = "";
  res.append(&(buf.front()));
  return res;
 }

 bool group::has_key(std::string const &key) const { return H5Lexists(id, key.c_str(), H5P_DEFAULT); }

 void group::unlink_key_if_exists(std::string const &key) const {
  if (!has_key(key)) return;
  //auto err = H5Gunlink(id, key.c_str()); // deprecated function
  auto err = H5Ldelete(id, key.c_str(),H5P_DEFAULT);
  if (err < 0) TRIQS_RUNTIME_ERROR << "Can not unlink object " << key << " in group " << name();
 }

 group group::open_group(std::string const &key) const {
  if (!has_key(key)) TRIQS_RUNTIME_ERROR << "no subgroup " << key << " in the group";
  hid_t sg = H5Gopen2(id, key.c_str(), H5P_DEFAULT);
  if (sg < 0) TRIQS_RUNTIME_ERROR << "Error in opening the subgroup " << key;
  return group(sg);
 }

 /// Open an existing DataSet. Throw it if does not exists
 dataset group::open_dataset(std::string const &key) const {
  if (!has_key(key)) TRIQS_RUNTIME_ERROR << "no dataset " << key << " in the group";
  dataset ds = H5Dopen2(id, key.c_str(), H5P_DEFAULT);
  if (!ds.is_valid()) TRIQS_RUNTIME_ERROR << "Can not open dataset " << key << " in the group" << name();
  return ds;
 }

 /**
  * \brief Create a subgroup.
  * \param key  The name of the subgroup
  * \param delete_if_exists  Unlink the group if it exists
  */
 group group::create_group(std::string const &key, bool delete_if_exists) const {
  unlink_key_if_exists(key);
  hid_t id_g = H5Gcreate2(id, key.c_str(), H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
  if (id_g < 0) TRIQS_RUNTIME_ERROR << "Can not create the subgroup " << key << " of the group" << name();
  return group(id_g);
 }

 /**
  * \brief Create a dataset.
  * \param key The name of the subgroup
  *
  * NB : It unlinks the dataset if it exists.
  */
 dataset group::create_dataset(std::string const &key, datatype ty, dataspace sp, hid_t pl) const {
  unlink_key_if_exists(key);
  dataset ds = H5Dcreate2(id, key.c_str(), ty, sp, H5P_DEFAULT, pl, H5P_DEFAULT);
  if (!ds.is_valid()) TRIQS_RUNTIME_ERROR << "Can not create the dataset " << key << " in the group" << name();
  return ds;
 }

 //----------------------------------------------------------
 // Keep as an example of H5LTset_attribute_string
 /*
 void group::write_string_attribute (std::string const & obj_name, std::string const & attr_name, std::string const & value){
  herr_t err = H5LTset_attribute_string(id, obj_name.c_str(), attr_name.c_str(), value.c_str());
  if (err<0) TRIQS_RUNTIME_ERROR << "Error in setting attribute of "<< obj_name<<" named "<< attr_name << " to " << value;
 }
*/
 //-----------------------------------------------------------------------

 // C callbacks for the next functions using H5Literate
 extern "C" {
 herr_t get_group_elements_name_ds(hid_t loc_id, const char *name, const H5L_info_t *info, void *opdata) {
  H5O_info_t object_info;
  herr_t err = H5Oget_info_by_name(loc_id, name, &object_info, H5P_DEFAULT);
  if (err < 0) TRIQS_RUNTIME_ERROR << "get_group_elements_name_ds internal";
  if (object_info.type == H5O_TYPE_DATASET) static_cast<std::vector<std::string> *>(opdata)->push_back(name);
  return 0;
 }
 herr_t get_group_elements_name_grp(hid_t loc_id, const char *name, const H5L_info_t *info, void *opdata) {
  H5O_info_t object_info;
  herr_t err = H5Oget_info_by_name(loc_id, name, &object_info, H5P_DEFAULT);
  if (err < 0) TRIQS_RUNTIME_ERROR << "get_group_elements_name_grp internal";
  if (object_info.type == H5O_TYPE_GROUP) static_cast<std::vector<std::string> *>(opdata)->push_back(name);
  return 0;
 }
 }
 //-----------------------------------------------------------------------

 std::vector<std::string> group::get_all_subgroup_names() const {
  std::vector<std::string> grp_name;
  int r = H5Literate(id, H5_INDEX_NAME, H5_ITER_NATIVE, NULL, get_group_elements_name_grp, static_cast<void *>(&grp_name));
  if (r != 0) TRIQS_RUNTIME_ERROR << "Iteration over subgroups of group " << name() << "failed";
  return grp_name;
 }

 std::vector<std::string> group::get_all_dataset_names() const {
  std::vector<std::string> ds_name;
  int r = H5Literate(id, H5_INDEX_NAME, H5_ITER_NATIVE, NULL, get_group_elements_name_ds, static_cast<void *>(&ds_name));
  if (r != 0) TRIQS_RUNTIME_ERROR << "Iteration over datasets of group " << name() << "failed";
  return ds_name;
 }
}
}