/*
  This file is part of TALER
  (C) 2014-2021 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 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 taler-merchant-httpd_post-orders-ID-paid.c
 * @brief handling of POST /orders/$ID/paid requests
 * @author Christian Grothoff
 */
#include "platform.h"
#include <taler/taler_dbevents.h>
#include <taler/taler_signatures.h>
#include <taler/taler_json_lib.h>
#include <taler/taler_exchange_service.h>
#include "taler-merchant-httpd_post-orders-ID-paid.h"


/**
 * Use database to notify other clients about the
 * session being captured.
 *
 * @param hc http context
 * @param session_id the captured session
 * @param fulfillment_url the URL that is now paid for by @a session_id
 */
static void
trigger_session_notification (struct TMH_HandlerContext *hc,
                              const char *session_id,
                              const char *fulfillment_url)
{
  struct TMH_SessionEventP session_eh = {
    .header.size = htons (sizeof (session_eh)),
    .header.type = htons (TALER_DBEVENT_MERCHANT_SESSION_CAPTURED),
    .merchant_pub = hc->instance->merchant_pub
  };

  GNUNET_CRYPTO_hash (session_id,
                      strlen (session_id),
                      &session_eh.h_session_id);
  GNUNET_CRYPTO_hash (fulfillment_url,
                      strlen (fulfillment_url),
                      &session_eh.h_fulfillment_url);
  TMH_db->event_notify (TMH_db->cls,
                        &session_eh.header,
                        NULL,
                        0);
}


MHD_RESULT
TMH_post_orders_ID_paid (const struct TMH_RequestHandler *rh,
                         struct MHD_Connection *connection,
                         struct TMH_HandlerContext *hc)
{
  struct TALER_PaymentResponsePS pr = {
    .purpose.purpose = htonl (TALER_SIGNATURE_MERCHANT_PAYMENT_OK),
    .purpose.size = htonl (sizeof (pr))
  };
  const char *order_id = hc->infix;
  struct TALER_MerchantSignatureP merchant_sig;
  const char *session_id;
  json_t *contract_terms;
  const char *fulfillment_url;
  enum GNUNET_DB_QueryStatus qs;

  {
    struct GNUNET_JSON_Specification spec[] = {
      GNUNET_JSON_spec_fixed_auto ("sig",
                                   &merchant_sig),
      GNUNET_JSON_spec_fixed_auto ("h_contract",
                                   &pr.h_contract_terms),
      GNUNET_JSON_spec_string ("session_id",
                               &session_id),
      GNUNET_JSON_spec_end ()
    };
    enum GNUNET_GenericReturnValue res;

    res = TALER_MHD_parse_json_data (connection,
                                     hc->request_body,
                                     spec);
    if (GNUNET_YES != res)
    {
      GNUNET_break_op (0);
      return (GNUNET_NO == res)
             ? MHD_YES
             : MHD_NO;
    }
  }


  if (GNUNET_OK !=
      GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MERCHANT_PAYMENT_OK,
                                  &pr,
                                  &merchant_sig.eddsa_sig,
                                  &hc->instance->merchant_pub.eddsa_pub))
  {
    GNUNET_break_op (0);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_FORBIDDEN,
                                       TALER_EC_MERCHANT_POST_ORDERS_ID_PAID_COIN_SIGNATURE_INVALID,
                                       NULL);
  }

  TMH_db->preflight (TMH_db->cls);
  {
    uint64_t order_serial;

    qs = TMH_db->lookup_contract_terms (TMH_db->cls,
                                        hc->instance->settings.id,
                                        order_id,
                                        &contract_terms,
                                        &order_serial,
                                        NULL);
  }
  if (0 > qs)
  {
    /* single, read-only SQL statements should never cause
       serialization problems */
    GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR != qs);
    /* Always report on hard error as well to enable diagnostics */
    GNUNET_break (GNUNET_DB_STATUS_HARD_ERROR == qs);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
                                       TALER_EC_GENERIC_DB_FETCH_FAILED,
                                       "lookup_contract_terms");
  }
  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Unknown order id given: `%s'\n",
                order_id);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_NOT_FOUND,
                                       TALER_EC_MERCHANT_GENERIC_ORDER_UNKNOWN,
                                       order_id);
  }

  {
    struct TALER_PrivateContractHash h_contract_terms;

    if (GNUNET_OK !=
        TALER_JSON_contract_hash (contract_terms,
                                  &h_contract_terms))
    {
      GNUNET_break (0);
      json_decref (contract_terms);
      return TALER_MHD_reply_with_error (connection,
                                         MHD_HTTP_INTERNAL_SERVER_ERROR,
                                         TALER_EC_GENERIC_FAILED_COMPUTE_JSON_HASH,
                                         NULL);
    }
    if (0 != GNUNET_memcmp (&pr.h_contract_terms,
                            &h_contract_terms))
    {
      json_decref (contract_terms);
      return TALER_MHD_reply_with_error (connection,
                                         MHD_HTTP_BAD_REQUEST,
                                         TALER_EC_MERCHANT_POST_ORDERS_ID_PAID_CONTRACT_HASH_MISMATCH,
                                         NULL);
    }
  }


  fulfillment_url
    = json_string_value (json_object_get (contract_terms,
                                          "fulfillment_url"));
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Marking contract %s with %s/%s as paid\n",
              order_id,
              session_id,
              fulfillment_url);
  qs = TMH_db->mark_contract_paid (TMH_db->cls,
                                   hc->instance->settings.id,
                                   &pr.h_contract_terms,
                                   session_id);
  /* If the order was paid already, we get qs == 0. */
  if (0 > qs)
  {
    GNUNET_break (0);
    json_decref (contract_terms);
    return TALER_MHD_reply_with_error (connection,
                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
                                       TALER_EC_GENERIC_DB_STORE_FAILED,
                                       "mark_contract_paid");
  }

  /* Wake everybody up who waits for this fulfillment_url and session_id */
  if ( (NULL != fulfillment_url) &&
       (NULL != session_id) )
    trigger_session_notification (hc,
                                  session_id,
                                  fulfillment_url);
  /* fulfillment_url is part of the contract_terms */
  json_decref (contract_terms);
  return TALER_MHD_reply_static (connection,
                                 MHD_HTTP_NO_CONTENT,
                                 NULL,
                                 NULL,
                                 0);
}


/* end of taler-merchant-httpd_post-orders-ID-paid.c */