/*
   This file is part of TALER
   Copyright (C) 2022,2023 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 backenddb/pg_lookup_orders.c
 * @brief Implementation of the lookup_orders function for Postgres
 * @author Iván Ávalos
 * @author Christian Grothoff
 */
#include "platform.h"
#include <taler/taler_error_codes.h>
#include <taler/taler_dbevents.h>
#include <taler/taler_pq_lib.h>
#include "pg_lookup_orders.h"
#include "pg_helper.h"

/**
 * Context used for TMH_PG_lookup_orders().
 */
struct LookupOrdersContext
{
  /**
   * Function to call with the results.
   */
  TALER_MERCHANTDB_OrdersCallback cb;

  /**
   * Closure for @a cb.
   */
  void *cb_cls;

  /**
   * Did database result extraction fail?
   */
  bool extract_failed;
};


/**
 * Function to be called with the results of a SELECT statement
 * that has returned @a num_results results about orders.
 *
 * @param[in,out] cls of type `struct LookupOrdersContext *`
 * @param result the postgres result
 * @param num_results the number of results in @a result
 */
static void
lookup_orders_cb (void *cls,
                  PGresult *result,
                  unsigned int num_results)
{
  struct LookupOrdersContext *plc = cls;

  for (unsigned int i = 0; i < num_results; i++)
  {
    char *order_id;
    uint64_t order_serial;
    struct GNUNET_TIME_Timestamp ts;
    struct GNUNET_PQ_ResultSpec rs[] = {
      GNUNET_PQ_result_spec_string ("order_id",
                                    &order_id),
      GNUNET_PQ_result_spec_uint64 ("order_serial",
                                    &order_serial),
      GNUNET_PQ_result_spec_timestamp ("creation_time",
                                       &ts),
      GNUNET_PQ_result_spec_end
    };

    if (GNUNET_OK !=
        GNUNET_PQ_extract_result (result,
                                  rs,
                                  i))
    {
      GNUNET_break (0);
      plc->extract_failed = true;
      return;
    }
    plc->cb (plc->cb_cls,
             order_id,
             order_serial,
             ts);
    GNUNET_PQ_cleanup_result (rs);
  }
}


enum GNUNET_DB_QueryStatus
TMH_PG_lookup_orders (void *cls,
                      const char *instance_id,
                      const struct TALER_MERCHANTDB_OrderFilter *of,
                      TALER_MERCHANTDB_OrdersCallback cb,
                      void *cb_cls)
{
  struct PostgresClosure *pg = cls;
  struct LookupOrdersContext plc = {
    .cb = cb,
    .cb_cls = cb_cls
  };
  uint64_t limit = (of->delta > 0) ? of->delta : -of->delta;
  struct GNUNET_PQ_QueryParam params[] = {
    /* $1 */
    GNUNET_PQ_query_param_string (instance_id),
    GNUNET_PQ_query_param_uint64 (&limit),
    GNUNET_PQ_query_param_uint64 (&of->start_row),
    GNUNET_PQ_query_param_timestamp (&of->date),
    GNUNET_PQ_query_param_bool ((TALER_EXCHANGE_YNA_ALL == of->paid)),
    /* $6 */
    GNUNET_PQ_query_param_bool ((TALER_EXCHANGE_YNA_YES == of->paid)),
    GNUNET_PQ_query_param_bool ((TALER_EXCHANGE_YNA_ALL == of->refunded)),
    GNUNET_PQ_query_param_bool ((TALER_EXCHANGE_YNA_YES == of->refunded)),
    GNUNET_PQ_query_param_bool ((TALER_EXCHANGE_YNA_ALL == of->wired)),
    GNUNET_PQ_query_param_bool ((TALER_EXCHANGE_YNA_YES == of->wired)),
    /* $11 */
    GNUNET_PQ_query_param_bool (NULL == of->session_id),
    NULL == of->session_id
    ? GNUNET_PQ_query_param_null ()
    : GNUNET_PQ_query_param_string (of->session_id),
    GNUNET_PQ_query_param_bool (NULL == of->fulfillment_url),
    NULL == of->fulfillment_url
    ? GNUNET_PQ_query_param_null ()
    : GNUNET_PQ_query_param_string (of->fulfillment_url),
    GNUNET_PQ_query_param_end
  };
  enum GNUNET_DB_QueryStatus qs;
  char stmt[128];

  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Looking up orders, using filter paid:%d, refunded: %d, wired: %d\n",
              of->paid,
              of->refunded,
              of->wired);
  GNUNET_snprintf (stmt,
                   sizeof (stmt),
                   "lookup_orders_%s",
                   (of->delta > 0) ? "inc" : "dec");
  PREPARE (pg,
           "lookup_orders_dec",
           "(SELECT"
           " order_id"
           ",order_serial"
           ",creation_time"
           " FROM merchant_orders"
           " WHERE merchant_orders.merchant_serial="
           "     (SELECT merchant_serial "
           "        FROM merchant_instances"
           "        WHERE merchant_id=$1)"
           "   AND"
           "    order_serial < $3"
           "   AND"
           "    creation_time < $4"
           "   AND ($5 OR "
           "    NOT CAST($6 AS BOOL))" /* unclaimed orders are never paid */
           "   AND ($7 OR "
           "    NOT CAST($8 AS BOOL))"/* unclaimed orders are never refunded */
           "   AND ($9 OR "
           "    NOT CAST($10 AS BOOL))" /* unclaimed orders are never wired */
           "   AND"
           "    order_serial NOT IN"
           "     (SELECT order_serial"
           "      FROM merchant_contract_terms)" /* only select unclaimed orders */
           "   AND ($11 OR "
           "     ($12 = session_id))"
           "   AND ($13 OR "
           "     ($14 = fulfillment_url))"
           " ORDER BY order_serial DESC"
           " LIMIT $2)"
           "UNION " /* union ensures elements are distinct! */
           "(SELECT"
           " order_id"
           ",order_serial"
           ",creation_time"
           " FROM merchant_contract_terms"
           " WHERE merchant_contract_terms.merchant_serial="
           "     (SELECT merchant_serial "
           "        FROM merchant_instances"
           "        WHERE merchant_id=$1)"
           "   AND"
           "    order_serial < $3"
           "   AND"
           "    creation_time < $4"
           "   AND ($5 OR "
           "    (CAST($6 AS BOOL) = paid))"
           "   AND ($7 OR "
           "    (CAST($8 AS BOOL) = (order_serial IN"
           "     (SELECT order_serial "
           "      FROM merchant_refunds))))"
           "   AND ($9 OR"
           "     (CAST($10 AS BOOL) = wired))"
           "   AND ($11 OR "
           "     ($12 = session_id))"
           "   AND ($13 OR "
           "     ($14 = fulfillment_url))"
           " ORDER BY order_serial DESC"
           " LIMIT $2)"
           " ORDER BY order_serial DESC"
           " LIMIT $2");

  PREPARE (pg,
           "lookup_orders_inc",
           "(SELECT"
           " order_id"
           ",order_serial"
           ",creation_time"
           " FROM merchant_orders"
           " WHERE merchant_orders.merchant_serial="
           "     (SELECT merchant_serial "
           "        FROM merchant_instances"
           "        WHERE merchant_id=$1)"
           "   AND"
           "    order_serial > $3"
           "   AND"
           "    creation_time > $4"
           "   AND ($5 OR "
           "    NOT CAST($6 AS BOOL))" /* unclaimed orders are never paid */
           "   AND ($7 OR "
           "    NOT CAST($8 AS BOOL))"/* unclaimed orders are never refunded */
           "   AND ($9 OR "
           "    NOT CAST($10 AS BOOL))" /* unclaimed orders are never wired */
           "   AND"
           "    (order_serial NOT IN"
           "     (SELECT order_serial"
           "      FROM merchant_contract_terms))" /* only select unclaimed orders */
           "   AND ($11 OR "
           "     ($12 = session_id))"
           "   AND ($13 OR "
           "     ($14 = fulfillment_url))"
           " ORDER BY order_serial ASC"
           " LIMIT $2)"
           "UNION " /* union ensures elements are distinct! */
           "(SELECT"
           " order_id"
           ",order_serial"
           ",creation_time"
           " FROM merchant_contract_terms"
           " WHERE merchant_contract_terms.merchant_serial="
           "     (SELECT merchant_serial "
           "        FROM merchant_instances"
           "        WHERE merchant_id=$1)"
           "   AND"
           "    order_serial > $3"
           "   AND"
           "    creation_time > $4"
           "   AND ($5 OR "
           "    (CAST($6 AS BOOL) = paid))"
           "   AND ($7 OR "
           "    (CAST($8 AS BOOL) = (order_serial IN"
           "     (SELECT order_serial "
           "      FROM merchant_refunds))))"
           "   AND ($9 OR"
           "    (CAST($10 AS BOOL) = wired))"
           "   AND ($11 OR "
           "     ($12 = session_id))"
           "   AND ($13 OR "
           "     ($14 = fulfillment_url))"
           " ORDER BY order_serial ASC"
           " LIMIT $2)"
           " ORDER BY order_serial ASC"
           " LIMIT $2");

  qs = GNUNET_PQ_eval_prepared_multi_select (pg->conn,
                                             stmt,
                                             params,
                                             &lookup_orders_cb,
                                             &plc);
  if (plc.extract_failed)
    return GNUNET_DB_STATUS_HARD_ERROR;
  return qs;
}