/*
     This file is part of GNUnet.
     Copyright (C) 2012 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet 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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */

/**
 * @file util/gnunet-config.c
 * @brief tool to access and manipulate GNUnet configuration files
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_util_lib.h"


/**
 * Name of the section
 */
static char *section;

/**
 * Name of the option
 */
static char *option;

/**
 * Value to set
 */
static char *value;

/**
 * Backend to check if the respective plugin is
 * loadable. NULL if no check is to be performed.
 * The value is the "basename" of the plugin to load.
 */
static char *backend_check;

/**
 * Treat option as a filename.
 */
static int is_filename;

/**
 * Whether to show the sections.
 */
static int list_sections;

/**
 * Return value from 'main'.
 */
static int global_ret;

/**
 * Should we generate a configuration file that is clean and
 * only contains the deltas to the defaults?
 */
static int rewrite;


/**
 * Print each option in a given section.
 *
 * @param cls closure
 * @param section name of the section
 * @param option name of the option
 * @param value value of the option
 */
static void
print_option(void *cls,
             const char *section,
             const char *option,
             const char *value)
{
  const struct GNUNET_CONFIGURATION_Handle *cfg = cls;

  (void)section;
  if (is_filename)
    {
      char *value_fn;
      char *fn;

      GNUNET_assert(GNUNET_OK ==
                    GNUNET_CONFIGURATION_get_value_filename(cfg,
                                                            section,
                                                            option,
                                                            &value_fn));
      fn = GNUNET_STRINGS_filename_expand(value_fn);
      if (NULL == fn)
        fn = value_fn;
      else
        GNUNET_free(value_fn);
      fprintf(stdout, "%s = %s\n", option, fn);
      GNUNET_free(fn);
    }
  else
    {
      fprintf(stdout, "%s = %s\n", option, value);
    }
}


/**
 * Print out given section name.
 *
 * @param cls unused
 * @param section a section in the configuration file
 */
static void
print_section_name(void *cls, const char *section)
{
  (void)cls;
  fprintf(stdout, "%s\n", section);
}


/**
 * Main function that will be run by the scheduler.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving,
 *                                                     can be NULL!)
 * @param cfg configuration
 */
static void
run(void *cls,
    char *const *args,
    const char *cfgfile,
    const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  struct GNUNET_CONFIGURATION_Handle *out = NULL;
  struct GNUNET_CONFIGURATION_Handle *diff = NULL;
  char *cfg_fn;

  (void)cls;
  (void)args;
  if (NULL != backend_check)
    {
      char *name;

      GNUNET_asprintf(&name, "libgnunet_plugin_%s", backend_check);
      global_ret = (GNUNET_OK == GNUNET_PLUGIN_test(name)) ? 0 : 77;
      GNUNET_free(name);
      return;
    }
  if (rewrite)
    {
      struct GNUNET_CONFIGURATION_Handle *def;

      def = GNUNET_CONFIGURATION_create();
      if (GNUNET_OK != GNUNET_CONFIGURATION_load(def, NULL))
        {
          fprintf(stderr, _("failed to load configuration defaults"));
          global_ret = 1;
          return;
        }
      diff = GNUNET_CONFIGURATION_get_diff(def, cfg);
      cfg = diff;
    }
  if (((!rewrite) && (NULL == section)) || list_sections)
    {
      if (!list_sections)
        {
          fprintf(stderr,
                  _("%s or %s argument is required\n"),
                  "--section",
                  "--list-sections");
          global_ret = 1;
        }
      else
        {
          fprintf(stderr, _("The following sections are available:\n"));
          GNUNET_CONFIGURATION_iterate_sections(cfg, &print_section_name, NULL);
        }
      goto cleanup;
    }

  if ((NULL != section) && (NULL == value))
    {
      if (NULL == option)
        {
          GNUNET_CONFIGURATION_iterate_section_values(cfg,
                                                      section,
                                                      &print_option,
                                                      (void *)cfg);
        }
      else
        {
          if (is_filename)
            {
              if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename(cfg,
                                                                       section,
                                                                       option,
                                                                       &value))
                {
                  GNUNET_log_config_missing(GNUNET_ERROR_TYPE_ERROR, section, option);
                  global_ret = 3;
                  goto cleanup;
                }
            }
          else
            {
              if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string(cfg,
                                                                     section,
                                                                     option,
                                                                     &value))
                {
                  GNUNET_log_config_missing(GNUNET_ERROR_TYPE_ERROR, section, option);
                  global_ret = 3;
                  goto cleanup;
                }
            }
          fprintf(stdout, "%s\n", value);
        }
    }
  else if (NULL != section)
    {
      if (NULL == option)
        {
          fprintf(stderr, _("--option argument required to set value\n"));
          global_ret = 1;
          goto cleanup;
        }
      out = GNUNET_CONFIGURATION_dup(cfg);
      GNUNET_CONFIGURATION_set_value_string(out, section, option, value);
    }
  cfg_fn = NULL;
  if (NULL == cfgfile)
    {
      const char *xdg = getenv("XDG_CONFIG_HOME");
      if (NULL != xdg)
        GNUNET_asprintf(&cfg_fn,
                        "%s%s%s",
                        xdg,
                        DIR_SEPARATOR_STR,
                        GNUNET_OS_project_data_get()->config_file);
      else
        cfg_fn = GNUNET_strdup(GNUNET_OS_project_data_get()->user_config_file);
      cfgfile = cfg_fn;
    }
  if ((NULL != diff) || (NULL != out))
    {
      if (GNUNET_OK !=
          GNUNET_CONFIGURATION_write((NULL == out) ? diff : out, cfgfile))
        global_ret = 2;
    }
  GNUNET_free_non_null(cfg_fn);
  if (NULL != out)
    GNUNET_CONFIGURATION_destroy(out);
cleanup:
  if (NULL != diff)
    GNUNET_CONFIGURATION_destroy(diff);
}


/**
 * Program to manipulate configuration files.
 *
 * @param argc number of arguments from the command line
 * @param argv command line arguments
 * @return 0 ok, 1 on error
 */
int
main(int argc, char *const *argv)
{
  struct GNUNET_GETOPT_CommandLineOption options[] =
  { GNUNET_GETOPT_option_flag(
      'f',
      "filename",
      gettext_noop("interpret option value as a filename (with $-expansion)"),
      &is_filename),
    GNUNET_GETOPT_option_exclusive(GNUNET_GETOPT_option_string(
                                     'b',
                                     "supported-backend",
                                     "BACKEND",
                                     gettext_noop(
                                       "test if the current installation supports the specified BACKEND"),
                                     &backend_check)),
    GNUNET_GETOPT_option_string('s',
                                "section",
                                "SECTION",
                                gettext_noop(
                                  "name of the section to access"),
                                &section),
    GNUNET_GETOPT_option_string('o',
                                "option",
                                "OPTION",
                                gettext_noop("name of the option to access"),
                                &option),
    GNUNET_GETOPT_option_string('V',
                                "value",
                                "VALUE",
                                gettext_noop("value to set"),
                                &value),
    GNUNET_GETOPT_option_flag('S',
                              "list-sections",
                              gettext_noop(
                                "print available configuration sections"),
                              &list_sections),
    GNUNET_GETOPT_option_flag(
      'w',
      "rewrite",
      gettext_noop(
        "write configuration file that only contains delta to defaults"),
      &rewrite),
    GNUNET_GETOPT_OPTION_END };
  int ret;

  if (GNUNET_OK != GNUNET_STRINGS_get_utf8_args(argc, argv, &argc, &argv))
    return 2;

  ret =
    GNUNET_PROGRAM_run(argc,
                       argv,
                       "gnunet-config [OPTIONS]",
                       gettext_noop("Manipulate GNUnet configuration files"),
                       options,
                       &run,
                       NULL);
  GNUNET_free((void *)argv);
  if (GNUNET_OK == ret)
    return global_ret;
  return ret;
}

/* end of gnunet-config.c */