/*
  This file is part of TALER
  Copyright (C) 2023 Taler Systems SA

  TALER 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, or (at your option) any later version.

  TALER 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
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file merchant-tools/taler-merchant-passwd.c
 * @brief Reset access tokens for instances.
 * @author Christian Grothoff
 */
#include "platform.h"
#include <taler/taler_util.h>
#include <taler/taler_dbevents.h>
#include <gnunet/gnunet_util_lib.h>
#include "taler_merchantdb_lib.h"
#include "taler_merchantdb_lib.h"

/**
 * Instance to set password for.
 */
static char *instance;

/**
 * Return value from main().
 */
static int global_ret;

/**
 * Main function that will be run.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 * @param config configuration
 */
static void
run (void *cls,
     char *const *args,
     const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *config)
{
  struct TALER_MERCHANTDB_Plugin *plugin;
  struct GNUNET_CONFIGURATION_Handle *cfg;
  const char *pw = args[0];
  struct TALER_MERCHANTDB_InstanceAuthSettings ias;
  enum GNUNET_DB_QueryStatus qs;

  if (NULL == pw)
    pw = getenv ("TALER_MERCHANT_PASSWORD");
  if (NULL == pw)
  {
    fprintf (stderr,
             "New password not specified (pass on command-line or via TALER_MERCHANT_PASSWORD)\n");
    global_ret = -1;
    return;
  }
  if (0 != strncmp (pw,
                    RFC_8959_PREFIX,
                    strlen (RFC_8959_PREFIX)))
  {
    fprintf (stderr,
             "Invalid password specified, does not begin with `%s'\n",
             RFC_8959_PREFIX);
    global_ret = 1;
    return;
  }
  if (NULL == instance)
    instance = GNUNET_strdup ("default");
  cfg = GNUNET_CONFIGURATION_dup (config);
  if (NULL ==
      (plugin = TALER_MERCHANTDB_plugin_load (cfg)))
  {
    fprintf (stderr,
             "Failed to initialize database plugin.\n");
    global_ret = 1;
    GNUNET_CONFIGURATION_destroy (cfg);
    return;
  }

  GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE,
                              &ias.auth_salt,
                              sizeof (ias.auth_salt));
  GNUNET_assert (GNUNET_YES ==
                 GNUNET_CRYPTO_kdf (&ias.auth_hash,
                                    sizeof (ias.auth_hash),
                                    &ias.auth_salt,
                                    sizeof (ias.auth_salt),
                                    pw,
                                    strlen (pw),
                                    "merchant-instance-auth",
                                    strlen ("merchant-instance-auth"),
                                    NULL,
                                    0));
  if (GNUNET_OK !=
      plugin->connect (plugin->cls))
  {
    fprintf (stderr,
             "Failed to connect to database\n");
    global_ret = 1;
    TALER_MERCHANTDB_plugin_unload (plugin);
    GNUNET_CONFIGURATION_destroy (cfg);
    return;
  }
  qs = plugin->update_instance_auth (plugin->cls,
                                     instance,
                                     &ias);
  switch (qs)
  {
  case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
    {
      struct GNUNET_DB_EventHeaderP es = {
        .size = ntohs (sizeof (es)),
        .type = ntohs (TALER_DBEVENT_MERCHANT_INSTANCE_SETTINGS)
      };

      plugin->event_notify (plugin->cls,
                            &es,
                            instance,
                            strlen (instance) + 1);
    }
    break;
  case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
    fprintf (stderr,
             "Instance `%s' unknown, cannot reset token\n",
             instance);
    global_ret = 2;
    break;
  case GNUNET_DB_STATUS_SOFT_ERROR:
  case GNUNET_DB_STATUS_HARD_ERROR:
    fprintf (stderr,
             "Internal database error.\n");
    global_ret = 3;
    break;
  }
  TALER_MERCHANTDB_plugin_unload (plugin);
  GNUNET_CONFIGURATION_destroy (cfg);
}


/**
 * The main function of the database initialization tool.
 * Used to initialize the Taler Exchange's database.
 *
 * @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_string ('i',
                                 "instance",
                                 "ID",
                                 "which instance to reset the password of",
                                 &instance),

    GNUNET_GETOPT_option_version (PACKAGE_VERSION "-" VCS_VERSION),
    GNUNET_GETOPT_OPTION_END
  };
  enum GNUNET_GenericReturnValue ret;

  /* force linker to link against libtalerutil; if we do
     not do this, the linker may "optimize" libtalerutil
     away and skip #TALER_OS_init(), which we do need */
  (void) TALER_project_data_default ();
  if (GNUNET_OK !=
      GNUNET_STRINGS_get_utf8_args (argc, argv,
                                    &argc, &argv))
    return 4;
  ret = GNUNET_PROGRAM_run (
    argc, argv,
    "taler-merchant-passwd",
    gettext_noop ("Reset instance password"),
    options,
    &run, NULL);
  GNUNET_free_nz ((void *) argv);
  if (GNUNET_SYSERR == ret)
    return 3;
  if (GNUNET_NO == ret)
    return 0;
  return global_ret;
}


/* end of taler-merchant-passwd.c */