/*
     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/>.
*/

/**
 * @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;

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

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

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

  (void) cls;
  (void) args;
  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"));
      ret = 1;
      return;
    }
    diff = GNUNET_CONFIGURATION_get_diff (def,
                                          cfg);
    cfg = diff;
  }
  if ( ((! rewrite) && (NULL == section)) || list_sections)
  {
    if (! list_sections)
    {
      fprintf (stderr,
               _("--section argument is required\n"));
    }
    fprintf (stderr,
             _("The following sections are available:\n"));
    GNUNET_CONFIGURATION_iterate_sections (cfg,
                                           &print_section_name,
                                           NULL);
    ret = 1;
    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);
	  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);
	  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"));
      ret = 1;
      goto cleanup;
    }
    out = GNUNET_CONFIGURATION_dup (cfg);
    GNUNET_CONFIGURATION_set_value_string (out,
                                           section,
                                           option,
                                           value);
  }
  if ( (NULL != diff) || (NULL != out) )
  {
    if (GNUNET_OK !=
	GNUNET_CONFIGURATION_write ((NULL == out) ? diff : out,
                                    cfgfile))
      ret = 2;
  }
  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 ("obtain option of value as a filename (with $-expansion)"),
			       &is_filename),
    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
  };
  if (GNUNET_OK !=
      GNUNET_STRINGS_get_utf8_args (argc, argv,
                                    &argc, &argv))
    return 2;

  ret = (GNUNET_OK ==
	 GNUNET_PROGRAM_run (argc,
                             argv,
                             "gnunet-config [OPTIONS]",
			     gettext_noop ("Manipulate GNUnet configuration files"),
			     options,
                             &run, NULL)) ? 0 : ret;
  GNUNET_free ((void*) argv);
  return ret;
}

/* end of gnunet-config.c */