path: root/src/backend/taler-merchant-httpd_private-post-orders.c

/*
  This file is part of TALER
  (C) 2014-2023 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_private-post-orders.c
 * @brief the POST /orders handler
 * @author Christian Grothoff
 * @author Marcello Stanisci
 */
#include "platform.h"
#include <jansson.h>
#include <taler/taler_signatures.h>
#include <taler/taler_json_lib.h>
#include "taler-merchant-httpd_private-post-orders.h"
#include "taler-merchant-httpd_exchanges.h"
#include "taler-merchant-httpd_helper.h"
#include "taler-merchant-httpd_private-get-orders.h"


/**
 * How often do we retry the simple INSERT database transaction?
 */
#define MAX_RETRIES 3

/**
 * What is the label under which we find/place the merchant's
 * jurisdiction in the locations list by default?
 */
#define STANDARD_LABEL_MERCHANT_JURISDICTION "_mj"

/**
 * What is the label under which we find/place the merchant's
 * address in the locations list by default?
 */
#define STANDARD_LABEL_MERCHANT_ADDRESS "_ma"


/**
 * Generate the base URL for the given merchant instance.
 *
 * @param connection the MHD connection
 * @param instance_id the merchant instance ID
 * @returns the merchant instance's base URL
 */
static char *
make_merchant_base_url (struct MHD_Connection *connection,
                        const char *instance_id)
{
  struct GNUNET_Buffer buf;

  if (GNUNET_OK !=
      TMH_base_url_by_connection (connection,
                                  instance_id,
                                  &buf))
    return NULL;
  GNUNET_buffer_write_path (&buf,
                            "");
  return GNUNET_buffer_reap_str (&buf);
}


/**
 * Information about a product we are supposed to add to the order
 * based on what we know it from our inventory.
 */
struct InventoryProduct
{
  /**
   * Identifier of the product in the inventory.
   */
  const char *product_id;

  /**
   * Number of units of the product to add to the order.
   */
  uint32_t quantity;
};


/**
 * Handle for a rekey operation where we (re)request
 * the /keys from the exchange.
 */
struct RekeyExchange
{
  /**
   * Kept in a DLL.
   */
  struct RekeyExchange *prev;

  /**
   * Kept in a DLL.
   */
  struct RekeyExchange *next;

  /**
   * order this is for.
   */
  struct OrderContext *oc;

  /**
   * Base URL of the exchange.
   */
  char *url;

  /**
   * Request for keys.
   */
  struct TMH_EXCHANGES_KeysOperation *fo;

};


/**
 * Information we keep per order we are processing.
 */
struct OrderContext
{

  /**
   * Connection of the request.
   */
  struct MHD_Connection *connection;

  /**
   * Kept in a DLL while suspended.
   */
  struct OrderContext *next;

  /**
   * Kept in a DLL while suspended.
   */
  struct OrderContext *prev;

  /**
   * Handler context for the request.
   */
  struct TMH_HandlerContext *hc;

  /**
   * Hash of the POST request data, used to detect
   * idempotent requests.
   */
  struct TALER_MerchantPostDataHashP h_post_data;

  /**
   * Payment deadline.
   */
  struct GNUNET_TIME_Timestamp pay_deadline;

  /**
   * Set to how long refunds will be allowed.
   */
  struct GNUNET_TIME_Relative refund_delay;

  /**
   * Order we are building (modified as we process
   * the request).
   */
  json_t *order;

  /**
   * Array of exchanges we find acceptable for this
   * order.
   */
  json_t *exchanges;

  /**
   * RFC8905 payment target type to find a matching merchant account
   */
  const char *payment_target;

  /**
   * Wire method (and our bank account) we have selected
   * to be included for this order.
   */
  const struct TMH_WireMethod *wm;

  /**
   * Forced requests to /keys to update our exchange
   * information.
   */
  struct RekeyExchange *pending_reload_head;

  /**
   * Forced requests to /keys to update our exchange
   * information.
   */
  struct RekeyExchange *pending_reload_tail;

  /**
   * Claim token for the request.
   */
  struct TALER_ClaimTokenP claim_token;

  /**
   * Length of the @e inventory_products array.
   */
  unsigned int inventory_products_length;

  /**
   * Array of inventory products in the @e order.
   */
  struct InventoryProduct *inventory_products;

  /**
   * array of UUIDs used to reserve products from @a inventory_products.
   */
  struct GNUNET_Uuid *uuids;

  /**
   * Shared key to use with @e pos_algorithm.
   */
  const char *pos_key;

  /**
   * Our order ID. Pointer into @e order.
   */
  const char *order_id;

  /**
   * which product (by offset) is out of stock, UINT_MAX if all were in-stock
   */
  unsigned int out_of_stock_index;

  /**
   * Length of the @e uuids array.
   */
  unsigned int uuids_length;

  /**
   * #GNUNET_YES if suspended.
   */
  enum GNUNET_GenericReturnValue suspended;

  /**
   * Selected algorithm (by template) when we are to
   * generate an OTP code for payment confirmation.
   */
  enum TALER_MerchantConfirmationAlgorithm pos_algorithm;

  /**
   * Current phase of setting up the order.
   */
  enum
  {
    ORDER_PHASE_INIT,
    ORDER_PHASE_MERGE_INVENTORY,
    ORDER_PHASE_ADD_PAYMENT_DETAILS,
    ORDER_PHASE_PATCH_ORDER,
    ORDER_PHASE_SET_EXCHANGES,
    ORDER_PHASE_CHECK_CONTRACT,
    ORDER_PHASE_EXECUTE_ORDER,

    /**
     * Processing is done, we should return #MHD_YES.
     */
    ORDER_PHASE_FINISHED_MHD_YES,

    /**
     * Processing is done, we should return #MHD_NO.
     */
    ORDER_PHASE_FINISHED_MHD_NO
  } phase;

  /**
   * Set to true once we are sure that we have at
   * least one good exchange.
   */
  bool exchange_good;

  /**
   * Did we previously force reloading of /keys from
   * all exchanges? Set to 'true' to prevent us from
   * doing it again (and again...).
   */
  bool forced_reload;

};


/**
 * Kept in a DLL while suspended.
 */
static struct OrderContext *oc_head;

/**
 * Kept in a DLL while suspended.
 */
static struct OrderContext *oc_tail;


void
TMH_force_orders_resume ()
{
  struct OrderContext *oc;

  while (NULL != (oc = oc_head))
  {
    GNUNET_CONTAINER_DLL_remove (oc_head,
                                 oc_tail,
                                 oc);
    oc->suspended = GNUNET_SYSERR;
    MHD_resume_connection (oc->connection);
  }
}


/**
 * Update the phase of @a oc based on @a mret.
 *
 * @param[in,out] oc order to update phase for
 * @param mret #MHD_NO to close with #MHD_NO
 *             #MHD_YES to close with #MHD_YES
 */
static void
finalize_order (struct OrderContext *oc,
                MHD_RESULT mret)
{
  oc->phase = (MHD_YES == mret)
    ? ORDER_PHASE_FINISHED_MHD_YES
    : ORDER_PHASE_FINISHED_MHD_NO;
}


/**
 * Update the phase of @a oc based on @a ret.
 *
 * @param[in,out] oc order to update phase for
 * @param ret #GNUNET_SYSERR to close with #MHD_NO
 *            #GNUNET_NO to close with #MHD_YES
 *            #GNUNET_OK is not allowed!
 */
static void
finalize_order2 (struct OrderContext *oc,
                 enum GNUNET_GenericReturnValue ret)
{
  GNUNET_assert (GNUNET_OK != ret);
  oc->phase = (GNUNET_NO == ret)
    ? ORDER_PHASE_FINISHED_MHD_YES
    : ORDER_PHASE_FINISHED_MHD_NO;
}


/**
 * Generate an error response for @a oc.
 *
 * @param[in,out] oc order context to respond to
 * @param http_status HTTP status code to set
 * @param ec error code to set
 * @param detail error message detail to set
 */
static void
reply_with_error (struct OrderContext *oc,
                  unsigned int http_status,
                  enum TALER_ErrorCode ec,
                  const char *detail)
{
  MHD_RESULT mret;

  mret = TALER_MHD_reply_with_error (oc->connection,
                                     http_status,
                                     ec,
                                     detail);
  finalize_order (oc,
                  mret);
}


/**
 * Clean up memory used by @a cls.
 *
 * @param[in] cls the `struct OrderContext` to clean up
 */
static void
clean_order (void *cls)
{
  struct OrderContext *oc = cls;
  struct RekeyExchange *rx;

  while (NULL != (rx = oc->pending_reload_head))
  {
    GNUNET_CONTAINER_DLL_remove (oc->pending_reload_head,
                                 oc->pending_reload_tail,
                                 rx);
    TMH_EXCHANGES_keys4exchange_cancel (rx->fo);
    GNUNET_free (rx->url);
    GNUNET_free (rx);
  }
  if (NULL != oc->exchanges)
  {
    json_decref (oc->exchanges);
    oc->exchanges = NULL;
  }
  GNUNET_array_grow (oc->inventory_products,
                     oc->inventory_products_length,
                     0);
  GNUNET_array_grow (oc->uuids,
                     oc->uuids_length,
                     0);
  json_decref (oc->order);
  GNUNET_free (oc);
}


/**
 * Execute the database transaction to setup the order.
 *
 * @param[in,out] oc order context
 * @return transaction status, #GNUNET_DB_STATUS_SUCCESS_NO_RESULTS if @a uuids were insufficient to reserve required inventory
 */
static enum GNUNET_DB_QueryStatus
execute_transaction (struct OrderContext *oc)
{
  enum GNUNET_DB_QueryStatus qs;
  struct GNUNET_TIME_Timestamp timestamp;
  uint64_t order_serial;

  if (GNUNET_OK !=
      TMH_db->start (TMH_db->cls,
                     "insert_order"))
  {
    GNUNET_break (0);
    return GNUNET_DB_STATUS_HARD_ERROR;
  }
  /* Setup order */
  qs = TMH_db->insert_order (TMH_db->cls,
                             oc->hc->instance->settings.id,
                             oc->order_id,
                             &oc->h_post_data,
                             oc->pay_deadline,
                             &oc->claim_token,
                             oc->order,  /* called 'contract terms' at database. */
                             oc->pos_key,
                             oc->pos_algorithm);
  if (qs <= 0)
  {
    /* qs == 0: probably instance does not exist (anymore) */
    TMH_db->rollback (TMH_db->cls);
    return qs;
  }
  /* Migrate locks from UUIDs to new order: first release old locks */
  for (unsigned int i = 0; i<oc->uuids_length; i++)
  {
    qs = TMH_db->unlock_inventory (TMH_db->cls,
                                   &oc->uuids[i]);
    if (qs < 0)
    {
      TMH_db->rollback (TMH_db->cls);
      return qs;
    }
    /* qs == 0 is OK here, that just means we did not HAVE any lock under this
       UUID */
  }
  /* Migrate locks from UUIDs to new order: acquire new locks
     (note: this can basically ONLY fail on serializability OR
     because the UUID locks were insufficient for the desired
     quantities). */
  for (unsigned int i = 0; i<oc->inventory_products_length; i++)
  {
    qs = TMH_db->insert_order_lock (
      TMH_db->cls,
      oc->hc->instance->settings.id,
      oc->order_id,
      oc->inventory_products[i].product_id,
      oc->inventory_products[i].quantity);
    if (qs < 0)
    {
      TMH_db->rollback (TMH_db->cls);
      return qs;
    }
    if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
    {
      /* qs == 0: lock acquisition failed due to insufficient stocks */
      TMH_db->rollback (TMH_db->cls);
      oc->out_of_stock_index = i; /* indicate which product is causing the issue */
      return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;
    }
  }
  oc->out_of_stock_index = UINT_MAX;

  /* Get the order serial and timestamp for the order we just created to
     update long-poll clients. */
  qs = TMH_db->lookup_order_summary (TMH_db->cls,
                                     oc->hc->instance->settings.id,
                                     oc->order_id,
                                     &timestamp,
                                     &order_serial);
  if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT != qs)
  {
    TMH_db->rollback (TMH_db->cls);
    return qs;
  }
  TMH_notify_order_change (oc->hc->instance,
                           TMH_OSF_NONE,
                           timestamp,
                           order_serial);
  /* finally, commit transaction (note: if it fails, we ALSO re-acquire
     the UUID locks, which is exactly what we want) */
  qs = TMH_db->commit (TMH_db->cls);
  if (0 > qs)
    return qs;
  return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;   /* 1 == success! */
}


/**
 * Transform an order into a proposal and store it in the
 * database. Write the resulting proposal or an error message
 * of a MHD connection.
 *
 * @param[in,out] oc order context
 */
static void
execute_order (struct OrderContext *oc)
{
  const struct TALER_MERCHANTDB_InstanceSettings *settings =
    &oc->hc->instance->settings;
  struct TALER_Amount total;
  const char *summary;
  const char *fulfillment_msg = NULL;
  const json_t *products;
  const json_t *merchant;
  struct GNUNET_TIME_Timestamp timestamp;
  struct GNUNET_TIME_Timestamp refund_deadline = { 0 };
  struct GNUNET_TIME_Timestamp wire_transfer_deadline;
  struct GNUNET_JSON_Specification spec[] = {
    TALER_JSON_spec_amount ("amount",
                            TMH_currency,
                            &total),
    GNUNET_JSON_spec_string ("order_id",
                             &oc->order_id),
    TALER_JSON_spec_i18n_str ("summary",
                              &summary),
    /**
     * The following entries we don't actually need,
     * except to check that the order is well-formed */
    GNUNET_JSON_spec_array_const ("products",
                                  &products),
    GNUNET_JSON_spec_object_const ("merchant",
                                   &merchant),
    GNUNET_JSON_spec_mark_optional (
      TALER_JSON_spec_i18n_str ("fulfillment_message",
                                &fulfillment_msg),
      NULL),
    GNUNET_JSON_spec_timestamp ("timestamp",
                                &timestamp),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_timestamp ("refund_deadline",
                                  &refund_deadline),
      NULL),
    GNUNET_JSON_spec_timestamp ("pay_deadline",
                                &oc->pay_deadline),
    GNUNET_JSON_spec_timestamp ("wire_transfer_deadline",
                                &wire_transfer_deadline),
    GNUNET_JSON_spec_end ()
  };
  enum GNUNET_DB_QueryStatus qs;

  /* extract fields we need to sign separately */
  {
    enum GNUNET_GenericReturnValue res;

    res = TALER_MHD_parse_json_data (oc->connection,
                                     oc->order,
                                     spec);
    if (GNUNET_OK != res)
    {
      GNUNET_break_op (0);
      finalize_order2 (oc,
                       res);
      return;
    }
  }

  /* check product list in contract is well-formed */
  if (! TMH_products_array_valid (products))
  {
    GNUNET_JSON_parse_free (spec);
    GNUNET_break_op (0);
    reply_with_error (oc,
                      MHD_HTTP_BAD_REQUEST,
                      TALER_EC_GENERIC_PARAMETER_MALFORMED,
                      "order:products");
    return;
  }

  /* Test if we already have an order with this id */
  {
    struct TALER_ClaimTokenP token;
    json_t *contract_terms;
    struct TALER_MerchantPostDataHashP orig_post;

    TMH_db->preflight (TMH_db->cls);
    qs = TMH_db->lookup_order (TMH_db->cls,
                               oc->hc->instance->settings.id,
                               oc->order_id,
                               &token,
                               &orig_post,
                               &contract_terms);
    /* If yes, check for idempotency */
    if (0 > qs)
    {
      GNUNET_break (0);
      TMH_db->rollback (TMH_db->cls);
      GNUNET_JSON_parse_free (spec);
      reply_with_error (oc,
                        MHD_HTTP_INTERNAL_SERVER_ERROR,
                        TALER_EC_GENERIC_DB_FETCH_FAILED,
                        "lookup_order");
      return;
    }
    if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs)
    {
      MHD_RESULT ret;

      json_decref (contract_terms);
      /* Comparing the contract terms is sufficient because all the other
         params get added to it at some point. */
      if (0 == GNUNET_memcmp (&orig_post,
                              &oc->h_post_data))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                    "Order creation idempotent\n");
        ret = TALER_MHD_REPLY_JSON_PACK (
          oc->connection,
          MHD_HTTP_OK,
          GNUNET_JSON_pack_string ("order_id",
                                   oc->order_id),
          GNUNET_JSON_pack_allow_null (
            GNUNET_JSON_pack_data_varsize (
              "token",
              GNUNET_is_zero (&token)
              ? NULL
              : &token,
              sizeof (token))));
        GNUNET_JSON_parse_free (spec);
        finalize_order (oc,
                        ret);
        return;
      }
      /* This request is not idempotent */
      GNUNET_break_op (0);
      reply_with_error (
        oc,
        MHD_HTTP_CONFLICT,
        TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_ALREADY_EXISTS,
        oc->order_id);
      GNUNET_JSON_parse_free (spec);
      return;
    }
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Executing database transaction to create order '%s' for instance '%s'\n",
              oc->order_id,
              settings->id);
  for (unsigned int i = 0; i<MAX_RETRIES; i++)
  {
    TMH_db->preflight (TMH_db->cls);
    qs = execute_transaction (oc);
    if (GNUNET_DB_STATUS_SOFT_ERROR != qs)
      break;
  }
  if (0 >= qs)
  {
    GNUNET_JSON_parse_free (spec);
    /* Special report if retries insufficient */
    if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
    {
      GNUNET_break (0);
      reply_with_error (oc,
                        MHD_HTTP_INTERNAL_SERVER_ERROR,
                        TALER_EC_GENERIC_DB_SOFT_FAILURE,
                        NULL);
      return;
    }
    if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
    {
      /* should be: contract (!) with same order ID
         already exists */
      reply_with_error (
        oc,
        MHD_HTTP_CONFLICT,
        TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_ALREADY_EXISTS,
        oc->order_id);
      return;
    }
    /* Other hard transaction error (disk full, etc.) */
    GNUNET_break (0);
    reply_with_error (
      oc,
      MHD_HTTP_INTERNAL_SERVER_ERROR,
      TALER_EC_GENERIC_DB_COMMIT_FAILED,
      NULL);
    return;
  }

  /* DB transaction succeeded, check for out-of-stock */
  if (oc->out_of_stock_index < UINT_MAX)
  {
    /* We had a product that has insufficient quantities,
       generate the details for the response. */
    struct TALER_MERCHANTDB_ProductDetails pd;
    MHD_RESULT ret;

    memset (&pd,
            0,
            sizeof (pd));
    qs = TMH_db->lookup_product (
      TMH_db->cls,
      oc->hc->instance->settings.id,
      oc->inventory_products[oc->out_of_stock_index].product_id,
      &pd);
    GNUNET_JSON_parse_free (spec);
    switch (qs)
    {
    case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                  "Order creation failed: product out of stock\n");
      ret = TALER_MHD_REPLY_JSON_PACK (
        oc->connection,
        MHD_HTTP_GONE,
        GNUNET_JSON_pack_string (
          "product_id",
          oc->inventory_products[oc->out_of_stock_index].product_id),
        GNUNET_JSON_pack_uint64 (
          "requested_quantity",
          oc->inventory_products[oc->out_of_stock_index].quantity),
        GNUNET_JSON_pack_uint64 (
          "available_quantity",
          pd.total_stock - pd.total_sold - pd.total_lost),
        GNUNET_JSON_pack_allow_null (
          GNUNET_JSON_pack_timestamp (
            "restock_expected",
            pd.next_restock)));
      TALER_MERCHANTDB_product_details_free (&pd);
      finalize_order (oc,
                      ret);
      return;
    case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                  "Order creation failed: unknown product out of stock\n");
      finalize_order (oc,
                      TALER_MHD_REPLY_JSON_PACK (
                        oc->connection,
                        MHD_HTTP_GONE,
                        GNUNET_JSON_pack_string (
                          "product_id",
                          oc->inventory_products[oc->out_of_stock_index].
                          product_id),
                        GNUNET_JSON_pack_uint64 (
                          "requested_quantity",
                          oc->inventory_products[oc->out_of_stock_index].
                          quantity),
                        GNUNET_JSON_pack_uint64 (
                          "available_quantity",
                          0)));
      return;
    case GNUNET_DB_STATUS_SOFT_ERROR:
      GNUNET_break (0);
      reply_with_error (
        oc,
        MHD_HTTP_INTERNAL_SERVER_ERROR,
        TALER_EC_GENERIC_DB_SOFT_FAILURE,
        NULL);
      return;
    case GNUNET_DB_STATUS_HARD_ERROR:
      GNUNET_break (0);
      reply_with_error (
        oc,
        MHD_HTTP_INTERNAL_SERVER_ERROR,
        TALER_EC_GENERIC_DB_FETCH_FAILED,
        NULL);
      return;
    }
    GNUNET_break (0);
    oc->phase = ORDER_PHASE_FINISHED_MHD_NO;
    return;
  } /* end 'out of stock' case */

  /* Everything in-stock, generate positive response */
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Order creation succeeded\n");
  {
    MHD_RESULT ret;

    ret = TALER_MHD_REPLY_JSON_PACK (
      oc->connection,
      MHD_HTTP_OK,
      GNUNET_JSON_pack_string ("order_id",
                               oc->order_id),
      GNUNET_JSON_pack_allow_null (
        GNUNET_JSON_pack_data_varsize (
          "token",
          GNUNET_is_zero (&oc->claim_token)
          ? NULL
          : &oc->claim_token,
          sizeof (oc->claim_token))));
    GNUNET_JSON_parse_free (spec);
    finalize_order (oc,
                    ret);
  }
}


/**
 * Check that the contract is now well-formed.
 *
 * @param[in,out] oc order context
 */
static void
check_contract (struct OrderContext *oc)
{
  struct TALER_PrivateContractHashP h_control;

  switch (TALER_JSON_contract_hash (oc->order,
                                    &h_control))
  {
  case GNUNET_SYSERR:
    GNUNET_break (0);
    reply_with_error (
      oc,
      MHD_HTTP_INTERNAL_SERVER_ERROR,
      TALER_EC_GENERIC_FAILED_COMPUTE_JSON_HASH,
      "could not compute hash of patched order");
    return;
  case GNUNET_NO:
    GNUNET_break_op (0);
    reply_with_error (
      oc,
      MHD_HTTP_BAD_REQUEST,
      TALER_EC_GENERIC_FAILED_COMPUTE_JSON_HASH,
      "order contained unallowed values");
    return;
  case GNUNET_OK:
    oc->phase++;
    return;
  }
  GNUNET_assert (0);
}


/**
 * Compute the set of exchanges that would be acceptable
 * for this order.
 *
 * @param cls our `struct OrderContext`
 * @param url base URL of an exchange (not used)
 * @param exchange internal handle for the exchange
 */
static void
get_acceptable (void *cls,
                const char *url,
                const struct TMH_Exchange *exchange)
{
  struct OrderContext *oc = cls;
  unsigned int priority;
  json_t *j_exchange;
  enum GNUNET_GenericReturnValue res;

  res = TMH_exchange_check_debit (exchange,
                                  oc->wm);
  switch (res)
  {
  case GNUNET_OK:
    priority = 1024;   /* high */
    oc->exchange_good = true;
    break;
  case GNUNET_NO:
    if (oc->forced_reload)
      priority = 0;   /* fresh negative response */
    else
      priority = 512; /* stale negative response */
    break;
  case GNUNET_SYSERR:
    if (oc->forced_reload)
      priority = 256;   /* fresh, no accounts yet */
    else
      priority = 768;  /* stale, no accounts yet */
    break;
  }
  j_exchange = GNUNET_JSON_PACK (
    GNUNET_JSON_pack_string ("url",
                             url),
    GNUNET_JSON_pack_uint64 ("priority",
                             priority),
    GNUNET_JSON_pack_data_auto ("master_pub",
                                TMH_EXCHANGES_get_master_pub (exchange)));
  GNUNET_assert (NULL != j_exchange);
  GNUNET_assert (0 ==
                 json_array_append_new (oc->exchanges,
                                        j_exchange));
}


/**
 * Function called with the result of a #TMH_EXCHANGES_keys4exchange()
 * operation.
 *
 * @param cls closure with our `struct RekeyExchange *`
 * @param keys the keys of the exchange
 * @param exchange representation of the exchange
 */
static void
keys_forced (
  void *cls,
  struct TALER_EXCHANGE_Keys *keys,
  struct TMH_Exchange *exchange)
{
  struct RekeyExchange *rx = cls;
  struct OrderContext *oc = rx->oc;

  rx->fo = NULL;
  GNUNET_CONTAINER_DLL_remove (oc->pending_reload_head,
                               oc->pending_reload_tail,
                               rx);
  if (NULL == keys)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Failed to download %s/keys\n",
                rx->url);
  }
  get_acceptable (oc,
                  rx->url,
                  exchange);
  GNUNET_free (rx->url);
  GNUNET_free (rx);
  if (NULL != oc->pending_reload_head)
    return;
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Resuming order processing after /keys downloads (now have %u accounts)\n",
              (unsigned int) json_array_size (oc->exchanges));
  GNUNET_assert (GNUNET_YES == oc->suspended);
  GNUNET_CONTAINER_DLL_remove (oc_head,
                               oc_tail,
                               oc);
  oc->suspended = GNUNET_NO;
  MHD_resume_connection (oc->connection);
  TALER_MHD_daemon_trigger (); /* we resumed, kick MHD */
}


/**
 * Force re-downloading of /keys from @a exchange,
 * we currently have no acceptable exchange, so we
 * should try to get one.
 *
 * @param cls closure with our `struct OrderContext`
 * @param url base URL of the exchange
 * @param exchange internal handle for the exchange
 */
static void
rekey_exchanges (void *cls,
                 const char *url,
                 const struct TMH_Exchange *exchange)
{
  struct OrderContext *oc = cls;
  struct RekeyExchange *rx;

  rx = GNUNET_new (struct RekeyExchange);
  rx->oc = oc;
  rx->url = GNUNET_strdup (url);
  GNUNET_CONTAINER_DLL_insert (oc->pending_reload_head,
                               oc->pending_reload_tail,
                               rx);
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Forcing download of %s/keys\n",
              url);
  rx->fo = TMH_EXCHANGES_keys4exchange (url,
                                        true,
                                        &keys_forced,
                                        rx);
}


/**
 * Set list of acceptable exchanges in @a oc.
 *
 * @param[in,out] oc order context
 * @return true to suspend execution
 */
static bool
set_exchanges (struct OrderContext *oc)
{
  /* Note: re-building 'oc->exchanges' every time here might be a tad
     expensive; could likely consider caching the result if it starts to
     matter. */
  if (NULL == oc->exchanges)
    oc->exchanges = json_array ();
  TMH_exchange_get_trusted (&get_acceptable,
                            oc);
  if (! oc->exchange_good)
  {
    if (! oc->forced_reload)
    {
      oc->forced_reload = true;
      GNUNET_assert (0 ==
                     json_array_clear (oc->exchanges));
      TMH_exchange_get_trusted (&rekey_exchanges,
                                oc);
    }
    if (NULL != oc->pending_reload_head)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                  "Still trying to re-load /keys\n");
      MHD_suspend_connection (oc->connection);
      oc->suspended = GNUNET_YES;
      GNUNET_CONTAINER_DLL_insert (oc_head,
                                   oc_tail,
                                   oc);
      return true; /* reloads pending */
    }
    if (0 == json_array_size (oc->exchanges))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "Cannot create order: lacking trusted exchanges\n");
      reply_with_error (
        oc,
        MHD_HTTP_CONFLICT,
        TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_NO_EXCHANGES_FOR_WIRE_METHOD,
        oc->wm->wire_method);
      return false;
    }
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Creating order, but possibly without usable trusted exchanges\n");
  }
  /* 'set' is correct here: reference in oc->exchanges released in cleanup_order() */
  GNUNET_assert (0 ==
                 json_object_set (oc->order,
                                  "exchanges",
                                  oc->exchanges));
  oc->phase++;
  return false;
}


/**
 * Add missing fields to the order.  Upon success, continue
 * processing with execute_order().
 *
 * @param[in,out] oc order context
 */
static void
patch_order (struct OrderContext *oc)
{
  const struct TALER_MERCHANTDB_InstanceSettings *settings =
    &oc->hc->instance->settings;
  const char *order_id = NULL;
  const char *fulfillment_url = NULL;
  const char *merchant_base_url = NULL;
  const json_t *jmerchant = NULL;
  const json_t *delivery_location = NULL;
  struct TALER_Amount max_fee = { 0 };
  struct GNUNET_TIME_Timestamp timestamp
    = GNUNET_TIME_UNIT_ZERO_TS;
  struct GNUNET_TIME_Timestamp delivery_date
    = GNUNET_TIME_UNIT_ZERO_TS;
  struct GNUNET_TIME_Timestamp refund_deadline
    = GNUNET_TIME_UNIT_FOREVER_TS;
  struct GNUNET_TIME_Timestamp wire_deadline
    = GNUNET_TIME_UNIT_FOREVER_TS;
  /* auto_refund only needs to be type-checked,
   * mostly because in GNUnet relative times can't
   * be negative.  */
  struct GNUNET_TIME_Relative auto_refund;
  struct GNUNET_JSON_Specification spec[] = {
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_string ("merchant_base_url",
                               &merchant_base_url),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_object_const ("merchant",
                                     &jmerchant),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_string ("order_id",
                               &order_id),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_string ("fulfillment_url",
                               &fulfillment_url),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_timestamp ("timestamp",
                                  &timestamp),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_timestamp ("refund_deadline",
                                  &refund_deadline),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_timestamp ("pay_deadline",
                                  &oc->pay_deadline),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_timestamp ("wire_transfer_deadline",
                                  &wire_deadline),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      TALER_JSON_spec_amount ("max_fee",
                              TMH_currency,
                              &max_fee),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_timestamp ("delivery_date",
                                  &delivery_date),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_relative_time ("auto_refund",
                                      &auto_refund),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_object_const ("delivery_location",
                                     &delivery_location),
      NULL),
    GNUNET_JSON_spec_end ()
  };
  enum GNUNET_GenericReturnValue ret;

  ret = TALER_MHD_parse_json_data (oc->connection,
                                   oc->order,
                                   spec);
  if (GNUNET_OK != ret)
  {
    GNUNET_break_op (0);
    finalize_order2 (oc,
                     ret);
    return;
  }

  /* Add order_id if it doesn't exist. */
  if (NULL == order_id)
  {
    char buf[256];
    time_t timer;
    struct tm *tm_info;
    size_t off;
    uint64_t rand;
    char *last;
    json_t *jbuf;

    time (&timer);
    tm_info = localtime (&timer);
    if (NULL == tm_info)
    {
      GNUNET_JSON_parse_free (spec);
      reply_with_error (
        oc,
        MHD_HTTP_INTERNAL_SERVER_ERROR,
        TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_NO_LOCALTIME,
        NULL);
    }
    off = strftime (buf,
                    sizeof (buf) - 1,
                    "%Y.%j",
                    tm_info);
    /* Check for error state of strftime */
    GNUNET_assert (0 != off);
    buf[off++] = '-';
    rand = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK,
                                     UINT64_MAX);
    last = GNUNET_STRINGS_data_to_string (&rand,
                                          sizeof (uint64_t),
                                          &buf[off],
                                          sizeof (buf) - off);
    GNUNET_assert (NULL != last);
    *last = '\0';
    jbuf = json_string (buf);
    GNUNET_assert (NULL != jbuf);
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Assigning order ID `%s' server-side\n",
                buf);
    GNUNET_break (0 ==
                  json_object_set_new (oc->order,
                                       "order_id",
                                       jbuf));
    order_id = json_string_value (jbuf);
    GNUNET_assert (NULL != order_id);
  }

  /* Patch fulfillment URL with order_id (implements #6467). */
  if (NULL != fulfillment_url)
  {
    const char *pos;

    pos = strstr (fulfillment_url,
                  "${ORDER_ID}");
    if (NULL != pos)
    {
      /* replace ${ORDER_ID} with the real order_id */
      char *nurl;

      /* We only allow one placeholder */
      if (strstr (pos + strlen ("${ORDER_ID}"),
                  "${ORDER_ID}"))
      {
        GNUNET_break_op (0);
        reply_with_error (oc,
                          MHD_HTTP_BAD_REQUEST,
                          TALER_EC_GENERIC_PARAMETER_MALFORMED,
                          "fulfillment_url");
        return;
      }

      GNUNET_asprintf (&nurl,
                       "%.*s%s%s",
                       /* first output URL until ${ORDER_ID} */
                       (int) (pos - fulfillment_url),
                       fulfillment_url,
                       /* replace ${ORDER_ID} with the right order_id */
                       order_id,
                       /* append rest of original URL */
                       pos + strlen ("${ORDER_ID}"));
      /* replace in JSON of the order */
      GNUNET_break (0 ==
                    json_object_set_new (oc->order,
                                         "fulfillment_url",
                                         json_string (nurl)));
      GNUNET_free (nurl);
    }
  }

  /* Check soundness of refund deadline, and that a timestamp
   * is actually present.  */
  {
    struct GNUNET_TIME_Timestamp now = GNUNET_TIME_timestamp_get ();

    /* Add timestamp if it doesn't exist (or is zero) */
    if (GNUNET_TIME_absolute_is_zero (timestamp.abs_time))
    {
      GNUNET_assert (0 ==
                     json_object_set_new (oc->order,
                                          "timestamp",
                                          GNUNET_JSON_from_timestamp (now)));
    }

    /* If no refund_deadline given, set one based on refund_delay.  */
    if (GNUNET_TIME_absolute_is_never (refund_deadline.abs_time))
    {
      if (GNUNET_TIME_relative_is_zero (oc->refund_delay))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                    "Refund delay is zero, no refunds are possible for this order\n");
        refund_deadline = GNUNET_TIME_UNIT_ZERO_TS;
      }
      else
      {
        refund_deadline = GNUNET_TIME_relative_to_timestamp (oc->refund_delay);
      }
      GNUNET_assert (0 ==
                     json_object_set_new (oc->order,
                                          "refund_deadline",
                                          GNUNET_JSON_from_timestamp (
                                            refund_deadline)));
    }
    if ( (! GNUNET_TIME_absolute_is_zero (delivery_date.abs_time)) &&
         (GNUNET_TIME_absolute_is_past (delivery_date.abs_time)) )
    {
      GNUNET_break_op (0);
      reply_with_error (
        oc,
        MHD_HTTP_BAD_REQUEST,
        TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_DELIVERY_DATE_IN_PAST,
        NULL);
      return;
    }
  }

  if (GNUNET_TIME_absolute_is_zero (oc->pay_deadline.abs_time))
  {
    oc->pay_deadline = GNUNET_TIME_relative_to_timestamp (
      settings->default_pay_delay);
    GNUNET_assert (0 ==
                   json_object_set_new (oc->order,
                                        "pay_deadline",
                                        GNUNET_JSON_from_timestamp (
                                          oc->pay_deadline)));
  }
  else if (GNUNET_TIME_absolute_is_past (oc->pay_deadline.abs_time))
  {
    GNUNET_break_op (0);
    reply_with_error (
      oc,
      MHD_HTTP_BAD_REQUEST,
      TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_PAY_DEADLINE_IN_PAST,
      NULL);
    return;
  }
  if ( (! GNUNET_TIME_absolute_is_zero (refund_deadline.abs_time)) &&
       (GNUNET_TIME_absolute_is_past (refund_deadline.abs_time)) )
  {
    GNUNET_break_op (0);
    reply_with_error (
      oc,
      MHD_HTTP_BAD_REQUEST,
      TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_REFUND_DEADLINE_IN_PAST,
      NULL);
    return;
  }

  if (GNUNET_TIME_absolute_is_never (wire_deadline.abs_time))
  {
    struct GNUNET_TIME_Timestamp t;

    t = GNUNET_TIME_relative_to_timestamp (
      GNUNET_TIME_relative_max (settings->default_wire_transfer_delay,
                                oc->refund_delay));
    wire_deadline = GNUNET_TIME_timestamp_max (refund_deadline,
                                               t);
    if (GNUNET_TIME_absolute_is_never (wire_deadline.abs_time))
    {
      GNUNET_break_op (0);
      reply_with_error (
        oc,
        MHD_HTTP_BAD_REQUEST,
        TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_WIRE_DEADLINE_IS_NEVER,
        "order:wire_transfer_deadline");
      return;
    }
    GNUNET_assert (0 ==
                   json_object_set_new (oc->order,
                                        "wire_transfer_deadline",
                                        GNUNET_JSON_from_timestamp (
                                          wire_deadline)));
  }
  if (GNUNET_TIME_timestamp_cmp (wire_deadline,
                                 <,
                                 refund_deadline))
  {
    GNUNET_break_op (0);
    reply_with_error (
      oc,
      MHD_HTTP_BAD_REQUEST,
      TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_REFUND_AFTER_WIRE_DEADLINE,
      "order:wire_transfer_deadline;order:refund_deadline");
    return;
  }

  /* Note: total amount currency match checked
     later in execute_order() */
  if (GNUNET_OK !=
      TALER_amount_is_valid (&max_fee))
  {
    struct TALER_Amount stefan;

    GNUNET_assert (GNUNET_OK ==
                   TALER_amount_set_zero (TMH_currency,
                                          &stefan));
    if (settings->use_stefan)
    {
      /* FIXME: update amount from stefan curve! */
      stefan.value = 5; // FIXME!
    }

    GNUNET_assert (0 ==
                   json_object_set_new (
                     oc->order,
                     "max_fee",
                     TALER_JSON_from_amount (&stefan)));
  }

  if (NULL == merchant_base_url)
  {
    char *url;

    url = make_merchant_base_url (oc->connection,
                                  settings->id);
    if (NULL == url)
    {
      GNUNET_break_op (0);
      reply_with_error (
        oc,
        MHD_HTTP_BAD_REQUEST,
        TALER_EC_GENERIC_PARAMETER_MISSING,
        "order:merchant_base_url");
      return;
    }
    GNUNET_assert (0 ==
                   json_object_set_new (oc->order,
                                        "merchant_base_url",
                                        json_string (url)));
    GNUNET_free (url);
  }
  else if (('\0' == *merchant_base_url) ||
           ('/' != merchant_base_url[strlen (merchant_base_url) - 1]))
  {
    GNUNET_break_op (0);
    reply_with_error (
      oc,
      MHD_HTTP_BAD_REQUEST,
      TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_PROPOSAL_PARSE_ERROR,
      "merchant_base_url is not valid");
    return;
  }

  /* Merchant information must not already be present */
  if (NULL != jmerchant)
  {
    GNUNET_break_op (0);
    reply_with_error (
      oc,
      MHD_HTTP_BAD_REQUEST,
      TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_PROPOSAL_PARSE_ERROR,
      "'merchant' field already set, but must be provided by backend");
    return;
  }

  {
    json_t *jm;

    jm = GNUNET_JSON_PACK (
      GNUNET_JSON_pack_string ("name",
                               settings->name),
      GNUNET_JSON_pack_allow_null (
        GNUNET_JSON_pack_string ("website",
                                 settings->website)),
      GNUNET_JSON_pack_allow_null (
        GNUNET_JSON_pack_string ("email",
                                 settings->email)),
      GNUNET_JSON_pack_allow_null (
        GNUNET_JSON_pack_string ("logo",
                                 settings->logo)));
    GNUNET_assert (NULL != jm);
    {
      json_t *loca;

      /* Handle merchant address */
      loca = settings->address;
      if (NULL != loca)
      {
        loca = json_deep_copy (loca);
        GNUNET_assert (0 ==
                       json_object_set_new (jm,
                                            "address",
                                            loca));
      }
    }
    {
      json_t *locj;

      /* Handle merchant jurisdiction */
      locj = settings->jurisdiction;
      if (NULL != locj)
      {
        locj = json_deep_copy (locj);
        GNUNET_assert (0 ==
                       json_object_set_new (jm,
                                            "jurisdiction",
                                            locj));
      }
    }
    GNUNET_assert (0 ==
                   json_object_set_new (oc->order,
                                        "merchant",
                                        jm));
  }

  GNUNET_assert (0 ==
                 json_object_set_new (oc->order,
                                      "merchant_pub",
                                      GNUNET_JSON_from_data_auto (
                                        &oc->hc->instance->merchant_pub)));

  if (GNUNET_OK !=
      TALER_JSON_contract_seed_forgettable (oc->order))
  {
    reply_with_error (
      oc,
      MHD_HTTP_BAD_REQUEST,
      TALER_EC_GENERIC_JSON_INVALID,
      "could not compute hash of order due to bogus forgettable fields");
    return;
  }

  if ( (NULL != delivery_location) &&
       (! TMH_location_object_valid (delivery_location)) )
  {
    GNUNET_break_op (0);
    reply_with_error (oc,
                      MHD_HTTP_BAD_REQUEST,
                      TALER_EC_GENERIC_PARAMETER_MALFORMED,
                      "delivery_location");
    return;
  }
  oc->phase++;
}


/**
 * Process the @a payment_target and add the details of how the
 * order could be paid to @a order. On success, continue
 * processing with patch_order().
 *
 * @param[in,out] oc order context
 */
static void
add_payment_details (struct OrderContext *oc)
{
  struct TMH_WireMethod *wm;

  wm = oc->hc->instance->wm_head;
  /* Locate wire method that has a matching payment target */
  while ( (NULL != wm) &&
          ( (! wm->active) ||
            ( (NULL != oc->payment_target) &&
              (0 != strcasecmp (oc->payment_target,
                                wm->wire_method) ) ) ) )
    wm = wm->next;
  if (NULL == wm)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "No wire method available for instance '%s'\n",
                oc->hc->instance->settings.id);
    reply_with_error (oc,
                      MHD_HTTP_NOT_FOUND,
                      TALER_EC_MERCHANT_PRIVATE_POST_ORDERS_INSTANCE_CONFIGURATION_LACKS_WIRE,
                      oc->payment_target);
    return;
  }
  oc->wm = wm;
  GNUNET_assert (0 ==
                 json_object_set_new (oc->order,
                                      "h_wire",
                                      GNUNET_JSON_from_data_auto (
                                        &wm->h_wire)));
  GNUNET_assert (0 ==
                 json_object_set_new (oc->order,
                                      "wire_method",
                                      json_string (wm->wire_method)));
  oc->phase++;
}


/**
 * Merge the inventory products into @a order, querying the
 * database about the details of those products. Upon success,
 * continue processing by calling add_payment_details().
 *
 * @param[in,out] oc order context to process
 */
static void
merge_inventory (struct OrderContext *oc)
{
  /**
   * inventory_products => instructions to add products to contract terms
   * order.products => contains products that are not from the backend-managed inventory.
   */
  {
    json_t *jprod = json_object_get (oc->order,
                                     "products");
    if (NULL == jprod)
    {
      GNUNET_assert (0 ==
                     json_object_set_new (oc->order,
                                          "products",
                                          json_array ()));
    }
    else if (! TMH_products_array_valid (jprod))
    {
      reply_with_error (oc,
                        MHD_HTTP_BAD_REQUEST,
                        TALER_EC_GENERIC_PARAMETER_MALFORMED,
                        "order.products");
      return;
    }
  }

  /* Populate products from inventory product array and database */
  {
    json_t *np = json_array ();

    GNUNET_assert (NULL != np);
    for (unsigned int i = 0; i<oc->inventory_products_length; i++)
    {
      struct TALER_MERCHANTDB_ProductDetails pd;
      enum GNUNET_DB_QueryStatus qs;

      qs = TMH_db->lookup_product (TMH_db->cls,
                                   oc->hc->instance->settings.id,
                                   oc->inventory_products[i].product_id,
                                   &pd);
      if (qs <= 0)
      {
        enum TALER_ErrorCode ec = TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
        unsigned int http_status = 0;

        switch (qs)
        {
        case GNUNET_DB_STATUS_HARD_ERROR:
          GNUNET_break (0);
          http_status = MHD_HTTP_INTERNAL_SERVER_ERROR;
          ec = TALER_EC_GENERIC_DB_FETCH_FAILED;
          break;
        case GNUNET_DB_STATUS_SOFT_ERROR:
          GNUNET_break (0);
          http_status = MHD_HTTP_INTERNAL_SERVER_ERROR;
          ec = TALER_EC_GENERIC_DB_SOFT_FAILURE;
          break;
        case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
          GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                      "Product %s from order unknown\n",
                      oc->inventory_products[i].product_id);
          http_status = MHD_HTTP_NOT_FOUND;
          ec = TALER_EC_MERCHANT_GENERIC_PRODUCT_UNKNOWN;
          break;
        case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
          /* case listed to make compilers happy */
          GNUNET_assert (0);
        }
        json_decref (np);
        reply_with_error (oc,
                          http_status,
                          ec,
                          oc->inventory_products[i].product_id);
        return;
      }
      {
        json_t *p;

        p = GNUNET_JSON_PACK (
          GNUNET_JSON_pack_string ("description",
                                   pd.description),
          GNUNET_JSON_pack_object_steal ("description_i18n",
                                         pd.description_i18n),
          GNUNET_JSON_pack_string ("unit",
                                   pd.unit),
          TALER_JSON_pack_amount ("price",
                                  &pd.price),
          GNUNET_JSON_pack_array_steal ("taxes",
                                        pd.taxes),
          GNUNET_JSON_pack_string ("image",
                                   pd.image),
          GNUNET_JSON_pack_uint64 (
            "quantity",
            oc->inventory_products[i].quantity));
        GNUNET_assert (NULL != p);
        GNUNET_assert (0 ==
                       json_array_append_new (np,
                                              p));
      }
      GNUNET_free (pd.description);
      GNUNET_free (pd.unit);
      GNUNET_free (pd.image);
      json_decref (pd.address);
    }
    /* merge into existing products list */
    {
      json_t *xp;

      xp = json_object_get (oc->order,
                            "products");
      GNUNET_assert (NULL != xp);
      json_array_extend (xp, np);
      json_decref (np);
    }
  }
  oc->phase++;
}


static void
parse_order_request (struct OrderContext *oc)
{
  const json_t *ip = NULL;
  const json_t *uuid = NULL;
  bool create_token = true; /* default */
  struct GNUNET_JSON_Specification spec[] = {
    GNUNET_JSON_spec_json ("order",
                           &oc->order),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_relative_time ("refund_delay",
                                      &oc->refund_delay),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_string ("payment_target",
                               &oc->payment_target),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_array_const ("inventory_products",
                                    &ip),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_array_const ("lock_uuids",
                                    &uuid),
      NULL),
    GNUNET_JSON_spec_mark_optional (
      GNUNET_JSON_spec_bool ("create_token",
                             &create_token),
      NULL),
    GNUNET_JSON_spec_end ()
  };
  enum GNUNET_GenericReturnValue ret;

  ret = TALER_MHD_parse_json_data (oc->connection,
                                   oc->hc->request_body,
                                   spec);
  if (GNUNET_OK != ret)
  {
    GNUNET_break_op (0);
    finalize_order2 (oc,
                     ret);
    return;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Refund delay is %s\n",
              GNUNET_TIME_relative2s (oc->refund_delay,
                                      false));
  TMH_db->expire_locks (TMH_db->cls);
  if (create_token)
  {
    GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE,
                                &oc->claim_token,
                                sizeof (oc->claim_token));
  }
  /* Compute h_post_data (for idempotency check) */
  {
    char *req_body_enc;

    /* Dump normalized JSON to string. */
    if (NULL == (req_body_enc
                   = json_dumps (oc->hc->request_body,
                                 JSON_ENCODE_ANY
                                 | JSON_COMPACT
                                 | JSON_SORT_KEYS)))
    {
      GNUNET_break (0);
      GNUNET_JSON_parse_free (spec);
      reply_with_error (oc,
                        MHD_HTTP_INTERNAL_SERVER_ERROR,
                        TALER_EC_GENERIC_ALLOCATION_FAILURE,
                        "request body normalization for hashing");
      return;
    }
    GNUNET_CRYPTO_hash (req_body_enc,
                        strlen (req_body_enc),
                        &oc->h_post_data.hash);
    GNUNET_free (req_body_enc);
  }

  /* parse the inventory_products (optionally given) */
  if (NULL != ip)
  {
    GNUNET_array_grow (oc->inventory_products,
                       oc->inventory_products_length,
                       json_array_size (ip));
    for (unsigned int i = 0; i<oc->inventory_products_length; i++)
    {
      struct InventoryProduct *ipr = &oc->inventory_products[i];
      const char *error_name;
      unsigned int error_line;
      struct GNUNET_JSON_Specification ispec[] = {
        GNUNET_JSON_spec_string ("product_id",
                                 &ipr->product_id),
        GNUNET_JSON_spec_uint32 ("quantity",
                                 &ipr->quantity),
        GNUNET_JSON_spec_end ()
      };

      ret = GNUNET_JSON_parse (json_array_get (ip,
                                               i),
                               ispec,
                               &error_name,
                               &error_line);
      if (GNUNET_OK != ret)
      {
        GNUNET_break_op (0);
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "Product parsing failed at #%u: %s:%u\n",
                    i,
                    error_name,
                    error_line);
        reply_with_error (oc,
                          MHD_HTTP_BAD_REQUEST,
                          TALER_EC_GENERIC_PARAMETER_MALFORMED,
                          "inventory_products");
        return;
      }
    }
  }

  /* parse the lock_uuids (optionally given) */
  if (NULL != uuid)
  {
    GNUNET_array_grow (oc->uuids,
                       oc->uuids_length,
                       json_array_size (uuid));
    for (unsigned int i = 0; i<oc->uuids_length; i++)
    {
      json_t *ui = json_array_get (uuid,
                                   i);

      if (! json_is_string (ui))
      {
        GNUNET_break_op (0);
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "UUID parsing failed at #%u\n",
                    i);
        reply_with_error (oc,
                          MHD_HTTP_BAD_REQUEST,
                          TALER_EC_GENERIC_PARAMETER_MALFORMED,
                          "lock_uuids");
        return;
      }
      TMH_uuid_from_string (json_string_value (ui),
                            &oc->uuids[i]);
    }
  }
  oc->phase++;
}


MHD_RESULT
TMH_private_post_orders_with_pos_secrets (
  const struct TMH_RequestHandler *rh,
  struct MHD_Connection *connection,
  struct TMH_HandlerContext *hc,
  const char *pos_key,
  enum TALER_MerchantConfirmationAlgorithm pos_algorithm)
{
  struct OrderContext *oc = hc->ctx;

  if (NULL == oc)
  {
    oc = GNUNET_new (struct OrderContext);
    hc->ctx = oc;
    hc->cc = &clean_order;
    oc->connection = connection;
    oc->hc = hc;
    oc->pos_key = pos_key;
    oc->pos_algorithm = pos_algorithm;
  }
  while (1)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Processing order in phase %d\n",
                oc->phase);
    switch (oc->phase)
    {
    case ORDER_PHASE_INIT:
      parse_order_request (oc);
      break;
    case ORDER_PHASE_MERGE_INVENTORY:
      merge_inventory (oc);
      break;
    case ORDER_PHASE_ADD_PAYMENT_DETAILS:
      add_payment_details (oc);
      break;
    case ORDER_PHASE_PATCH_ORDER:
      patch_order (oc);
      break;
    case ORDER_PHASE_SET_EXCHANGES:
      if (set_exchanges (oc))
        return MHD_YES;
      break;
    case ORDER_PHASE_CHECK_CONTRACT:
      check_contract (oc);
      break;
    case ORDER_PHASE_EXECUTE_ORDER:
      execute_order (oc);
      break;
    case ORDER_PHASE_FINISHED_MHD_YES:
      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                  "Finished processing order (1)\n");
      return MHD_YES;
    case ORDER_PHASE_FINISHED_MHD_NO:
      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                  "Finished processing order (0)\n");
      return MHD_NO;
    }
  }
}


MHD_RESULT
TMH_private_post_orders (
  const struct TMH_RequestHandler *rh,
  struct MHD_Connection *connection,
  struct TMH_HandlerContext *hc)
{
  return TMH_private_post_orders_with_pos_secrets (rh,
                                                   connection,
                                                   hc,
                                                   NULL,
                                                   TALER_MCA_NONE);
}


/* end of taler-merchant-httpd_private-post-orders.c */