/*
  This file is part of TALER
  Copyright (C) 2020, 2021 Taler Systems SA

  TALER 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, 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 Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License along with
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file taler-exchange-httpd_management_auditors.c
 * @brief Handle request to add auditor.
 * @author Christian Grothoff
 */
#include "platform.h"
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <jansson.h>
#include <microhttpd.h>
#include <pthread.h>
#include "taler_json_lib.h"
#include "taler_mhd_lib.h"
#include "taler-exchange-httpd_management.h"
#include "taler-exchange-httpd_responses.h"
#include "taler-exchange-httpd_keys.h"


/**
 * Closure for the #add_auditor transaction.
 */
struct AddAuditorContext
{
  /**
   * Master signature to store.
   */
  struct TALER_MasterSignatureP master_sig;

  /**
   * Auditor public key this is about.
   */
  struct TALER_AuditorPublicKeyP auditor_pub;

  /**
   * Auditor URL this is about.
   */
  const char *auditor_url;

  /**
   * Human readable name of the auditor.
   */
  const char *auditor_name;

  /**
   * Timestamp for checking against replay attacks.
   */
  struct GNUNET_TIME_Absolute validity_start;

};


/**
 * Function implementing database transaction to add an auditor.  Runs the
 * transaction logic; IF it returns a non-error code, the transaction logic
 * MUST NOT queue a MHD response.  IF it returns an hard error, the
 * transaction logic MUST queue a MHD response and set @a mhd_ret.  IF it
 * returns the soft error code, the function MAY be called again to retry and
 * MUST not queue a MHD response.
 *
 * @param cls closure with a `struct AddAuditorContext`
 * @param connection MHD request which triggered the transaction
 * @param session database session to use
 * @param[out] mhd_ret set to MHD response status for @a connection,
 *             if transaction failed (!)
 * @return transaction status
 */
static enum GNUNET_DB_QueryStatus
add_auditor (void *cls,
             struct MHD_Connection *connection,
             struct TALER_EXCHANGEDB_Session *session,
             MHD_RESULT *mhd_ret)
{
  struct AddAuditorContext *aac = cls;
  struct GNUNET_TIME_Absolute last_date;
  enum GNUNET_DB_QueryStatus qs;

  qs = TEH_plugin->lookup_auditor_timestamp (TEH_plugin->cls,
                                             session,
                                             &aac->auditor_pub,
                                             &last_date);
  if (qs < 0)
  {
    if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
      return qs;
    GNUNET_break (0);
    *mhd_ret = TALER_MHD_reply_with_error (connection,
                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
                                           TALER_EC_GENERIC_DB_FETCH_FAILED,
                                           "lookup auditor");
    return qs;
  }
  if ( (0 < qs) &&
       (last_date.abs_value_us > aac->validity_start.abs_value_us) )
  {
    *mhd_ret = TALER_MHD_reply_with_error (
      connection,
      MHD_HTTP_CONFLICT,
      TALER_EC_EXCHANGE_MANAGEMENT_AUDITOR_MORE_RECENT_PRESENT,
      NULL);
    return GNUNET_DB_STATUS_HARD_ERROR;
  }
  if (0 == qs)
    qs = TEH_plugin->insert_auditor (TEH_plugin->cls,
                                     session,
                                     &aac->auditor_pub,
                                     aac->auditor_url,
                                     aac->auditor_name,
                                     aac->validity_start);
  else
    qs = TEH_plugin->update_auditor (TEH_plugin->cls,
                                     session,
                                     &aac->auditor_pub,
                                     aac->auditor_url,
                                     aac->auditor_name,
                                     aac->validity_start,
                                     true);
  if (qs < 0)
  {
    GNUNET_break (0);
    if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
      return qs;
    *mhd_ret = TALER_MHD_reply_with_error (connection,
                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
                                           TALER_EC_GENERIC_DB_STORE_FAILED,
                                           "add auditor");
    return qs;
  }
  TEH_keys_update_states ();
  return qs;
}


MHD_RESULT
TEH_handler_management_auditors (
  struct MHD_Connection *connection,
  const json_t *root)
{
  struct AddAuditorContext aac;
  struct GNUNET_JSON_Specification spec[] = {
    GNUNET_JSON_spec_fixed_auto ("master_sig",
                                 &aac.master_sig),
    GNUNET_JSON_spec_fixed_auto ("auditor_pub",
                                 &aac.auditor_pub),
    GNUNET_JSON_spec_string ("auditor_url",
                             &aac.auditor_url),
    GNUNET_JSON_spec_string ("auditor_name",
                             &aac.auditor_name),
    TALER_JSON_spec_absolute_time ("validity_start",
                                   &aac.validity_start),
    GNUNET_JSON_spec_end ()
  };
  MHD_RESULT res;
  enum GNUNET_GenericReturnValue ret;

  ret = TALER_MHD_parse_json_data (connection,
                                   root,
                                   spec);
  if (GNUNET_SYSERR == ret)
    return MHD_NO;   /* hard failure */
  if (GNUNET_NO == ret)
    return MHD_YES;   /* failure */
  if (GNUNET_OK !=
      TALER_exchange_offline_auditor_add_verify (
        &aac.auditor_pub,
        aac.auditor_url,
        aac.validity_start,
        &TEH_master_public_key,
        &aac.master_sig))
  {
    GNUNET_break_op (0);
    return TALER_MHD_reply_with_error (
      connection,
      MHD_HTTP_FORBIDDEN,
      TALER_EC_EXCHANGE_MANAGEMENT_AUDITOR_ADD_SIGNATURE_INVALID,
      NULL);
  }

  ret = TEH_DB_run_transaction (connection,
                                "add auditor",
                                &res,
                                &add_auditor,
                                &aac);
  if (GNUNET_SYSERR == ret)
    return res;
  return TALER_MHD_reply_static (
    connection,
    MHD_HTTP_NO_CONTENT,
    NULL,
    NULL,
    0);
}


/* end of taler-exchange-httpd_management_auditors.c */