#include "platform.h"
#include <jansson.h>
#include <taler/taler_signatures.h>
#include <gnunet/gnunet_util_lib.h>
#include "merchant.h"
#include "merchant_db.h"
#include "taler_merchant_contract_lib.h"


/* TODO: make this file a library, and programmatically call the following
 * functions */

/**
 * Macro to round microseconds to seconds in GNUNET_TIME_* structs.
 */
#define ROUND_TO_SECS(name,us_field) name.us_field -= name.us_field % (1000 * 1000)

/**
 * Shorthand for exit jumps.
 */
#define EXITIF(cond)                                              \
  do {                                                            \
    if (cond) { GNUNET_break (0); goto EXITIF_exit; }             \
  } while (0)

/**
* Generate the hash containing the information (= a nounce + merchant's IBAN) to
* redeem money from mint in a subsequent /deposit operation
* @param nounce the nounce
* @param wire the merchant's wire details
* @return the hash to be included in the contract's blob
*
*/

static struct GNUNET_HashCode
hash_wireformat (uint64_t nounce, const struct MERCHANT_WIREFORMAT_Sepa *wire)
{
  struct GNUNET_HashContext *hc;
  struct GNUNET_HashCode hash;

  hc = GNUNET_CRYPTO_hash_context_start ();
  GNUNET_CRYPTO_hash_context_read (hc, wire->iban, strlen (wire->iban));
  GNUNET_CRYPTO_hash_context_read (hc, wire->name, strlen (wire->name));
  GNUNET_CRYPTO_hash_context_read (hc, wire->bic, strlen (wire->bic));
  nounce = GNUNET_htonll (nounce);
  GNUNET_CRYPTO_hash_context_read (hc, &nounce, sizeof (nounce));
  GNUNET_CRYPTO_hash_context_finish (hc, &hash);
  return hash;
}

/**
 * Take the global wire details and return a JSON containing them,
 * compliantly with the Taler's API.
 * @param wire the merchant's wire details
 * @param nounce the nounce for hashing the wire details with
 * @param edate when the beneficiary wants this transfer to take place
 * @return JSON representation of the wire details, NULL upon errors
 */

json_t *
MERCHANT_get_wire_json (const struct MERCHANT_WIREFORMAT_Sepa *wire,
                        uint64_t nounce,
                        const struct GNUNET_TIME_Absolute edate)

{
  
  json_t *root;
  json_t *j_edate;
  json_t *j_nounce;

  nounce = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_NONCE, UINT64_MAX);
  j_nounce = json_integer (nounce);
  j_edate = TALER_json_from_abs (edate);

  if (NULL == (root = json_pack ("{s:s, s:s, s:s, s:s, s:o}",
                                 "type", "SEPA",
		                 "IBAN", wire->iban,
		                 "name", wire->name,
		                 "BIC", wire->bic,
		                 "edate", j_edate,
		                 "r", json_integer_value (j_nounce))))
    return NULL;

  return root;
}



/**
* Take from the frontend the (partly) generated contract and fill
* the missing values in it; for example, the SEPA details.
* Moreover, it stores the contract in the DB.
* @param j_contract parsed contract, originated by the frontend. It will be
* hold the new values.
* @param db_conn the handle to the local DB
* @param contract where to store the (subset of the) contract to be (still) signed
* @param timestamp contract's timestamp (shall be generated by the merchant)
* @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 nounce the nounce used to hash the wire details
* @param contract_str where to store the (stringified) contract
* @return GNUNET_OK on success; GNUNET_SYSERR upon errors
*/

/**
* TODO: inspect reference counting and, accordingly, free those json_t*(s)
* still allocated */

uint32_t
MERCHANT_handle_contract (const json_t *j_contract,
                          PGconn *db_conn,
			  struct Contract *contract,
			  struct GNUNET_TIME_Absolute timestamp,
			  struct GNUNET_TIME_Absolute expiry,
			  struct GNUNET_TIME_Absolute edate,
			  uint64_t nounce,
			  const char *contract_str)
{
  json_t *j_amount;
  json_int_t j_product_id;
  json_int_t j_trans_id;

  struct TALER_Amount amount;



  /* Extracting values useful for DB work. Only gettable from the JSON
  since they are generated by the frontend */
  if (-1 == json_unpack (j_contract, "{s:o, s:I, s:{s:{s:I}}}",
                         "amount", &j_amount,
			 "trans_id", &j_trans_id,
			 "details", "items",
			 "product_id", &j_product_id))
  {
    printf ("no unpacking\n");
    return GNUNET_SYSERR;
  }

  /* needed for DB work */
  TALER_json_to_amount (j_amount, &amount); // produces a WARNING..

  contract_str = json_dumps (j_contract, JSON_COMPACT | JSON_PRESERVE_ORDER);
  GNUNET_CRYPTO_hash (contract_str, strlen (contract_str) + 1,
                      &contract->h_contract_details);
  contract->purpose.purpose = htonl (TALER_SIGNATURE_MERCHANT_CONTRACT);
  contract->purpose.size = htonl (sizeof (struct Contract));

  // DB mgmt
  if (GNUNET_SYSERR == MERCHANT_DB_contract_create (db_conn,
                                                    timestamp,
						    expiry,
						    edate,
                                                    &amount,
                                                    &contract->h_contract_details,
 					            (uint64_t) j_trans_id, // safe?
                                                    contract_str,
                                                    nounce,
                                                    (uint64_t) j_product_id))
    return GNUNET_SYSERR;

  return GNUNET_OK;
}