void nntp_hcache_update(struct NntpMboxData *mdata, struct HeaderCache *hc)
{

  char buf[32] = { 0 };
  bool old = false;
  anum_t first = 0, last = 0;

  /* fetch previous values of first and last */
  size_t dlen = 0;
  char *hdata = mutt_hcache_fetch_raw(hc, "index", 5, &dlen);
  if (hdata)
  {
    mutt_debug(LL_DEBUG2, "mutt_hcache_fetch index: %s\n", (char *) hdata);
    if ((dlen > 0) && (hdata[dlen - 1] == '\0') &&
        sscanf(hdata, ANUM " " ANUM, &first, &last) == 2)
    {
      old = true;
      mdata->last_cached = last;

      /* clean removed headers from cache */
      for (anum_t current = first; current <= last; current++)
      {
        if ((current >= mdata->first_message) && (current <= mdata->last_message))
          continue;

        snprintf(buf, sizeof(buf), ANUM, current);
        mutt_debug(LL_DEBUG2, "mutt_hcache_delete_record %s\n", buf);
        mutt_hcache_delete_record(hc, buf, strlen(buf));
      }
    }
    mutt_hcache_free_raw(hc, (void **) &hdata);
  }

  /* store current values of first and last */
  if (!old || (mdata->first_message != first) || (mdata->last_message != last))
  {
    snprintf(buf, sizeof(buf), ANUM " " ANUM, mdata->first_message, mdata->last_message);
    mutt_debug(LL_DEBUG2, "mutt_hcache_store index: %s\n", buf);
    mutt_hcache_store_raw(hc, "index", 5, buf, strlen(buf) + 1);
  }
}

void nntp_clear_cache(struct NntpAccountData *adata)
{
  char file[PATH_MAX] = { 0 };
  char *fp = NULL;
  struct dirent *entry = NULL;
  DIR *dp = NULL;

  if (!adata || !adata->cacheable)
    return;

  cache_expand(file, sizeof(file), &adata->conn->account, NULL);
  dp = opendir(file);
  if (dp)
  {
    mutt_strn_cat(file, sizeof(file), "/", 1);
    fp = file + strlen(file);
    while ((entry = readdir(dp)))
    {
      char *group = entry->d_name;
      struct stat st = { 0 };
      struct NntpMboxData *mdata = NULL;
      struct NntpMboxData tmp_mdata;

      if (mutt_str_equal(group, ".") || mutt_str_equal(group, ".."))
        continue;
      *fp = '\0';
      mutt_strn_cat(file, sizeof(file), group, strlen(group));
      if (stat(file, &st) != 0)
        continue;

#ifdef USE_HCACHE
      if (S_ISREG(st.st_mode))
      {
        char *ext = group + strlen(group) - 7;
        if ((strlen(group) < 8) || !mutt_str_equal(ext, ".hcache"))
          continue;
        *ext = '\0';
      }
      else
#endif
          if (!S_ISDIR(st.st_mode))
        continue;

      const bool c_save_unsubscribed = cs_subset_bool(NeoMutt->sub, "save_unsubscribed");
      mdata = mutt_hash_find(adata->groups_hash, group);

    }
    closedir(dp);
  }
}

struct NntpAccountData *nntp_select_server(struct Mailbox *m, const char *server, bool leave_lock)
{
  /* news server already exists */
  // adata = conn->data;
    if (rc > 0)
      nntp_clear_cache(adata);
    if ((rc < 0) || !leave_lock)
      nntp_newsrc_close(adata);

  return adata;
}