/*
  This file is part of TALER
  Copyright (C) 2020 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 merchant-tools/taler-merchant-setup-reserve.c
 * @brief Create reserve for tipping
 * @author Christian Grothoff
 */
#include "platform.h"
#include <taler/taler_util.h>
#include <microhttpd.h>
#include <gnunet/gnunet_util_lib.h>
#include "taler_merchant_service.h"

/**
 * How often do we try before giving up?
 */
#define MAX_TRIES 30

/**
 * Return value from main().
 */
static int global_ret;

/**
 * Initial amount the reserve will be filled with.
 */
static struct TALER_Amount initial_amount;

/**
 * Base URL of the merchant (with instance) to create the reserve for.
 */
static char *merchant_base_url;

/**
 * Base URL of the exchange to create the reserve at.
 */
static char *exchange_base_url;

/**
 * Wire method to use.
 */
static char *wire_method;

/**
 * Operation handle.
 */
static struct TALER_MERCHANT_PostReservesHandle *prh;

/**
 * Our context for making HTTP requests.
 */
static struct GNUNET_CURL_Context *ctx;

/**
 * Reschedule context.
 */
static struct GNUNET_CURL_RescheduleContext *rc;

/**
 * Username and password to use for client authentication
 * (optional).
 */
static char *userpass;

/**
 * Type of the client's TLS certificate (optional).
 */
static char *certtype;

/**
 * File with the client's TLS certificate (optional).
 */
static char *certfile;

/**
 * File with the client's TLS private key (optional).
 */
static char *keyfile;

/**
 * This value goes in the Authorization:-header.
 */
static char *apikey;

/**
 * Passphrase to decrypt client's TLS private key file (optional).
 */
static char *keypass;

/**
 * How often have we tried?
 */
static unsigned int tries;

/**
 * Task to do the main work.
 */
static struct GNUNET_SCHEDULER_Task *task;


/**
 * Shutdown task (invoked when the process is being terminated)
 *
 * @param cls NULL
 */
static void
do_shutdown (void *cls)
{
  if (NULL != task)
  {
    GNUNET_SCHEDULER_cancel (task);
    task = NULL;
  }
  if (NULL != ctx)
  {
    GNUNET_CURL_fini (ctx);
    ctx = NULL;
  }
  if (NULL != rc)
  {
    GNUNET_CURL_gnunet_rc_destroy (rc);
    rc = NULL;
  }
  if (NULL != prh)
  {
    TALER_MERCHANT_reserves_post_cancel (prh);
    prh = NULL;
  }
}


/**
 * Function that makes the call to setup the reserve.
 *
 * @param cls NULL
 */
static void
do_request (void *cls);


/**
 * Callbacks of this type are used to work the result of submitting a
 * POST /reserves request to a merchant
 *
 * @param cls closure
 * @param prr response details
 */
static void
result_cb (void *cls,
           const struct TALER_MERCHANT_PostReservesResponse *prr)
{
  (void) cls;
  prh = NULL;
  switch (prr->hr.http_status)
  {
  case MHD_HTTP_OK:
    {
      char res_str[sizeof (prr->details.ok.reserve_pub) * 2 + 1];

      GNUNET_STRINGS_data_to_string (&prr->details.ok.reserve_pub,
                                     sizeof (prr->details.ok.reserve_pub),
                                     res_str,
                                     sizeof (res_str));
      for (unsigned int i = 0; i<prr->details.ok.accounts_len; i++)
      {
        const struct TALER_EXCHANGE_WireAccount *wa
          = &prr->details.ok.accounts[i];
        const char *payto_uri = wa->payto_uri;
        bool skip = false;

        for (unsigned int j = 0; j<wa->credit_restrictions_length; j++)
          if (TALER_EXCHANGE_AR_DENY ==
              wa->credit_restrictions[j].type)
            skip = true;
        if (skip)
          continue;
        if (NULL != strchr (payto_uri, '?'))
          fprintf (stdout,
                   "%s&message=%s\n",
                   payto_uri,
                   res_str);
        else
          fprintf (stdout,
                   "%s?message=%s\n",
                   payto_uri,
                   res_str);
        if (NULL != wa->conversion_url)
          fprintf (stdout,
                   "\tConversion needed: %s\n",
                   wa->conversion_url);
        for (unsigned int j = 0; j<wa->credit_restrictions_length; j++)
        {
          const struct TALER_EXCHANGE_AccountRestriction *cr
            = &wa->credit_restrictions[j];

          switch (cr->type)
          {
          case TALER_EXCHANGE_AR_INVALID:
            GNUNET_assert (0);
            break;
          case TALER_EXCHANGE_AR_DENY:
            GNUNET_assert (0);
            break;
          case TALER_EXCHANGE_AR_REGEX:
            fprintf (stdout,
                     "\tCredit restriction: %s (%s)\n",
                     cr->details.regex.human_hint,
                     cr->details.regex.posix_egrep);
            break;
          }
        }
      }
    }
    break;
  case MHD_HTTP_CONFLICT:
    fprintf (stderr,
             "Conflict trying to setup reserve: %u/%d\nHint: %s\n",
             prr->hr.http_status,
             (int) prr->hr.ec,
             prr->hr.hint);
    global_ret = 1;
    break;
  case MHD_HTTP_INTERNAL_SERVER_ERROR:
  case MHD_HTTP_BAD_GATEWAY:
    tries++;
    if (tries < MAX_TRIES)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "Merchant failed, will try again.\n");
      task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
                                           &do_request,
                                           NULL);
      return;
    }
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Merchant failed too often (%u/%d), giving up\n",
                prr->hr.http_status,
                prr->hr.ec);
    global_ret = 1;
    break;
  default:
    fprintf (stderr,
             "Unexpected backend failure: %u/%d\nHint: %s\n",
             prr->hr.http_status,
             (int) prr->hr.ec,
             prr->hr.hint);
    global_ret = 1;
    break;
  }
  GNUNET_SCHEDULER_shutdown ();
}


/**
 * Main function that will be run.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 * @param config configuration
 */
static void
run (void *cls,
     char *const *args,
     const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *config)
{
  /* setup HTTP client event loop */
  ctx = GNUNET_CURL_init (&GNUNET_CURL_gnunet_scheduler_reschedule,
                          &rc);
  rc = GNUNET_CURL_gnunet_rc_create (ctx);
  if (NULL != userpass)
    GNUNET_CURL_set_userpass (ctx,
                              userpass);
  if (NULL != keyfile)
    GNUNET_CURL_set_tlscert (ctx,
                             certtype,
                             certfile,
                             keyfile,
                             keypass);
  if (NULL != apikey)
  {
    char *auth_header;

    GNUNET_asprintf (&auth_header,
                     "%s: %s",
                     MHD_HTTP_HEADER_AUTHORIZATION,
                     apikey);
    if (GNUNET_OK !=
        GNUNET_CURL_append_header (ctx,
                                   auth_header))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Failed so set %s header, trying without\n",
                  MHD_HTTP_HEADER_AUTHORIZATION);
    }
    GNUNET_free (auth_header);
  }
  /* setup termination logic */
  GNUNET_SCHEDULER_add_shutdown (&do_shutdown,
                                 NULL);
  task = GNUNET_SCHEDULER_add_now (&do_request,
                                   NULL);
}


static void
do_request (void *cls)
{
  (void) cls;
  task = NULL;
  /* run actual (async) operation */
  prh = TALER_MERCHANT_reserves_post (ctx,
                                      merchant_base_url,
                                      &initial_amount,
                                      exchange_base_url,
                                      wire_method,
                                      &result_cb,
                                      NULL);
  if (NULL == prh)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to begin operation with merchant backend!\n");
    global_ret = 2;
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
}


/**
 * The main function for setting up reserves for tipping.
 *
 * @param argc number of arguments from the command line
 * @param argv command line arguments
 * @return 0 ok, 1 on error
 */
int
main (int argc,
      char *const *argv)
{
  struct GNUNET_GETOPT_CommandLineOption options[] = {
    GNUNET_GETOPT_option_mandatory (
      TALER_getopt_get_amount ('a',
                               "amount",
                               "VALUE",
                               "amount to be transferred into the reserve",
                               &initial_amount)),
    GNUNET_GETOPT_option_string ('A',
                                 "auth",
                                 "USERNAME:PASSWORD",
                                 "use the given USERNAME and PASSWORD for client authentication",
                                 &userpass),
    GNUNET_GETOPT_option_string ('C',
                                 "cert",
                                 "CERTFILE",
                                 "name of the TLS client certificate file",
                                 &certfile),
    GNUNET_GETOPT_option_mandatory (
      GNUNET_GETOPT_option_string ('e',
                                   "exchange-url",
                                   "URL",
                                   "base URL of the exchange to create the reserve at",
                                   &exchange_base_url)),
    GNUNET_GETOPT_option_string ('k',
                                 "key",
                                 "KEYFILE",
                                 "file with the private TLS key for TLS client authentication",
                                 &keyfile),
    GNUNET_GETOPT_option_mandatory (
      GNUNET_GETOPT_option_string ('m',
                                   "merchant-url",
                                   "URL",
                                   "base URL of the merchant backend's REST API",
                                   &merchant_base_url)),
    GNUNET_GETOPT_option_string ('p',
                                 "pass",
                                 "KEYFILEPASSPHRASE",
                                 "passphrase needed to decrypt the TLS client private key file",
                                 &keypass),
    GNUNET_GETOPT_option_string ('K',
                                 "apikey",
                                 "APIKEY",
                                 "API key to use in the HTTP request",
                                 &apikey),
    GNUNET_GETOPT_option_string ('t',
                                 "type",
                                 "CERTTYPE",
                                 "type of the TLS client certificate, defaults to PEM if not specified",
                                 &certtype),
    GNUNET_GETOPT_option_version (PACKAGE_VERSION "-" VCS_VERSION),
    GNUNET_GETOPT_option_mandatory (
      GNUNET_GETOPT_option_string ('w',
                                   "wire-method",
                                   "METHOD",
                                   "wire method to use for the wire transfer (i.e. IBAN)",
                                   &wire_method)),
    GNUNET_GETOPT_OPTION_END
  };
  enum GNUNET_GenericReturnValue ret;

  /* force linker to link against libtalerutil; if we do
     not do this, the linker may "optimize" libtalerutil
     away and skip #TALER_OS_init(), which we do need */
  (void) TALER_project_data_default ();
  if (GNUNET_OK !=
      GNUNET_STRINGS_get_utf8_args (argc, argv,
                                    &argc, &argv))
    return 4;
  ret = GNUNET_PROGRAM_run (
    argc, argv,
    "taler-merchant-setup-reserve",
    gettext_noop ("Setup reserve for tipping"),
    options,
    &run, NULL);
  GNUNET_free_nz ((void *) argv);
  if (GNUNET_SYSERR == ret)
    return 3;
  if (GNUNET_NO == ret)
    return 0;
  return global_ret;
}


/* end of taler-merchant-setup-reserve.c */