/*
  This file is part of TALER
  (C) 2014, 2015 Christian Grothoff (and other contributing authors)

  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, If not, see <http://www.gnu.org/licenses/>
*/

/**
 * @file include/taler_merchantdb_lib.h
 * @brief database helper functions used by the merchant backend
 * @author Sree Harsha Totakura <sreeharsha@totakura.in>
 */

#ifndef MERCHANT_DB_H
#define MERCHANT_DB_H

#include <gnunet/gnunet_postgres_lib.h>
#include <taler/taler_util.h>



/* Set of values that represent a contract. To be expanded on an
  as-needed basis */
struct TALER_MERCHANTDB_ContractHandle
{
  /* The nounce used when hashing the wire details
    for this contract */
  uint64_t nounce;

  /* The maximum time when the merchant expects the money tranfer
    to his bank account to happen */
  struct GNUNET_TIME_Absolute edate;

  /* The time when this contract was generated */
  struct GNUNET_TIME_Absolute timestamp;

  /* The maximum time until which the merchant could issue a
    refund to the customer */
  struct GNUNET_TIME_Absolute refund_deadline;

  /* The identification number for this contract */
  uint64_t contract_id;

};

/**
 * Connect to postgresql database
 *
 * @param cfg the configuration handle
 * @return connection to the postgresql database; NULL upon error
 */
PGconn *
TALER_MERCHANTDB_connect (const struct GNUNET_CONFIGURATION_Handle *cfg);


/**
 * Disconnect from the database
 *
 * @param conn database handle to close
 */
void
TALER_MERCHANTDB_disconnect (PGconn *conn);


/**
 * Initialize merchant tables
 *
 * @param conn the connection handle to postgres db.
 * @param tmp GNUNET_YES if the tables are to be made temporary i.e. their
 *          contents are dropped when the @a conn is closed
 * @return GNUNET_OK upon success; GNUNET_SYSERR upon failure
 */
int
TALER_MERCHANTDB_initialize (PGconn *conn, int tmp);


/**
 * Inserts a contract record into the database and if successfull returns the
 * serial number of the inserted row.
 *
 * @param conn the database connection
 * @param timestamp the timestamp of this contract
 * @param expiry the time when the contract will expire
 * @param edate when the merchant wants to receive the wire transfer corresponding
 * to this deal (this value is also a field inside the 'wire' JSON format)
 * @param refund deadline until which the merchant can return the paid amount
 * @param amount the taler amount corresponding to the contract
 * @param hash of the stringified JSON corresponding to this contract
 * @param c_id contract's id
 * @param desc descripition of the contract
 * @param nounce a random 64-bit nounce
 * @param product description to identify a product
 * @return #GNUNET_OK on success, #GNUNET_SYSERR upon error
 */
uint32_t
TALER_MERCHANTDB_contract_create (PGconn *conn,
                             const struct GNUNET_TIME_Absolute timestamp,
                             const struct GNUNET_TIME_Absolute expiry,
			     struct GNUNET_TIME_Absolute edate,
			     struct GNUNET_TIME_Absolute refund,
                             const struct TALER_Amount *amount,
			     const struct GNUNET_HashCode *h_contract,
			     uint64_t c_id,
                             const char *desc,
                             uint64_t nounce,
                             uint64_t product);


long long
TALER_MERCHANTDB_contract_get_product (PGconn *conn,
                                  uint64_t contract_id);


/**
 * Update the pending column of a deposit permission
 *
 * @param conn handle to DB
 * @param transaction_id identification number of the deposit to
 * update
 * @param pending true if still pending, false otherwise (i.e. the
 * mint did respond something)
 * @return #GNUNET_OK if successful, #GNUNET_SYSERR upon errors
 */
uint32_t
TALER_MERCHANTDB_deposit_permission_update (PGconn *conn,
                                       uint64_t transaction_id,
				       unsigned int pending);

unsigned int
TALER_MERCHANTDB_checkout_create (PGconn *conn,
                             struct GNUNET_CRYPTO_rsa_PublicKey *coin_pub,
                             uint64_t transaction_id,
                             struct TALER_Amount *amount,
                             struct GNUNET_CRYPTO_rsa_Signature *coin_sig);


long long
TALER_MERCHANTDB_checkout_get_product (PGconn *conn,
                                  struct GNUNET_CRYPTO_rsa_PublicKey *coin_pub);

/**
 * The query gets a contract's nounce and edate used to reproduce
 * a 'wire' JSON object. This function is also useful to check whether
 * a claimed contract existed or not.
 *
 * @param conn handle to the DB
 * @param h_contract the parameter for the row to match against
 * @param nounce where to store the found nounce
 * @param edate where to store the found expiration date
 * @return #GNUNET_OK on success, #GNUNET_SYSERR upon errors
 */
uint32_t
TALER_MERCHANTDB_contract_get_values (PGconn *conn,
                                 const struct GNUNET_HashCode *h_contract,
                                 uint64_t *nounce,
				 struct GNUNET_TIME_Absolute *edate);

#endif  /* MERCHANT_DB_H */

/**
 * Get a set of values representing a contract. This function is meant
 * to obsolete the '_get_contract_values' version.
 *
 * @param h_contract the hashcode of this contract
 * @param contract_handle where to store the results
 * @raturn #GNUNET_OK in case of success, #GNUNET_SYSERR
 * upon errors
 */
uint32_t
TALER_MERCHANTDB_contract_get_handle (PGconn *conn,
                                 const struct GNUNET_HashCode *h_contract,
				 struct TALER_MERCHANTDB_ContractHandle *contract_handle);

/**
 * Store a deposit permission in DB. To be mainly used if /deposit should
 * be retried; also, the merchant can benefit from this information in case
 * he needs to later investigate about some transaction_id.
 * @param conn DB handle
 * @param transaction_id identification number of this payment (which is the
 * same id of the related contract)
 * @param pending if true, this payment got to a persistent state
 * @param which mint is to get this deposit permission
 * @return #GNUNET_OK if successful, #GNUNET_SYSERR upon errors
 */
uint32_t
TALER_MERCHANTDB_deposit_permission_store (PGconn *conn,
                                      const char *deposit_permission,
				      uint64_t transaction_id,
				      unsigned int pending,
				      const char *mint_url);
/* end of merchant-db.h */