/*
  This file is part of TALER
  Copyright (C) 2014-2018 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 taler-wire.c
 * @brief Utility performing wire transfers.
 * @author Marcello Stanisci
 * @author Christian Grothoff
 */

#include <platform.h>
#include <gnunet/gnunet_util_lib.h>
#include <taler/taler_util.h>
#include <taler/taler_wire_lib.h>

/**
 * If set to GNUNET_YES, then we'll ask the bank for a list
 * of transactions from the account mentioned in the config
 * section.
 */
int history;

/**
 * If set to GNUNET_YES, then we'll ask the bank to execute a
 * wire transfer.
 */
int transfer;

/**
 * Name of the wire plugin to use with the bank.
 */
char *plugin_name;

/**
 * Global return code.
 */
unsigned int global_ret = 1;

/**
 * When a wire transfer is being performed, this value
 * specifies the amount to wire-transfer.  It's given in
 * the usual CURRENCY:X[.Y] format.
 */
char *amount;

/**
 * Base32 encoding of a transaction ID.  When asking the
 * bank for a transaction history, all the results will
 * have a transaction ID settled *after* this one.
 */
char *since_when;

/**
 * Which config section has the credentials to access the bank.
 */
char *account_section; 

/**
 * URL identifying the account that is going to receive the
 * wire transfer.
 */
char *destination_account_url;

/**
 * Handle for the wire transfer preparation task.
 */
struct TALER_WIRE_PrepareHandle *ph;

/**
 * Wire plugin handle.
 */
struct TALER_WIRE_Plugin *plugin_handle;


/**
 * Callback used to process ONE entry in the transaction
 * history returned by the bank.
 *
 * @param cls closure
 * @param ec taler error code
 * @param dir direction of the transfer
 * @param row_off identification of the position at
 *        which we are querying
 * @param row_off_size number of bytes in @a row_off
 * @param details details about the wire transfer
 * @return #GNUNET_OK to continue, #GNUNET_SYSERR to
 *         abort iteration
 */
int
history_cb (void *cls,
            enum TALER_ErrorCode ec,
            enum TALER_BANK_Direction dir,
            const void *row_off,
            size_t row_off_size,
            const struct TALER_WIRE_TransferDetails *details)
{
  char *row_off_enc;

  if (TALER_BANK_DIRECTION_NONE == dir)
  {
    fprintf (stdout,
             "End of transactions list.\n");
    global_ret = 0;
    GNUNET_SCHEDULER_shutdown ();
    return GNUNET_NO;
  }

  row_off_enc = GNUNET_STRINGS_data_to_string_alloc (row_off,
                                                     row_off_size);
  /* Give more details on screen (??) */
  fprintf (stdout,
           "%s\n",
           row_off_enc);

  GNUNET_free (row_off_enc);

  return GNUNET_OK;
}

/**
 * Callback that processes the outcome of a wire transfer
 * execution.
 */
void
confirmation_cb (void *cls,
                 int success,
                 const void *row_id,
                 size_t row_id_size,
                 const char *emsg)
{
  if (GNUNET_YES != success)
  {
    fprintf (stderr,
             "The wire transfer didn't execute correctly.\n"); 
    GNUNET_assert (NULL != emsg);
    fprintf (stderr,
             emsg);
    GNUNET_SCHEDULER_shutdown ();
    return;
  }

  fprintf (stdout,
           "Wire transfer executed successfully.\n");

  global_ret = 0;
  GNUNET_SCHEDULER_shutdown ();
}


/**
 * Takes prepared blob and executes the wire-transfer.
 *
 * @param cls NULL.
 * @param buf prepared wire transfer data.
 * @param buf_size size of the prepared wire transfer data.
 */
void
prepare_cb (void *cls,
            const char *buf,
            size_t buf_size)
{
  struct TALER_WIRE_ExecuteHandle *eh;

  if (NULL == (eh = plugin_handle->execute_wire_transfer
      (plugin_handle->cls,
      buf,
      buf_size,
      confirmation_cb,
      NULL)))
  {
    fprintf (stderr,
             "Could not execute the wire transfer\n"); 

    plugin_handle->prepare_wire_transfer_cancel
      (plugin_handle->cls,
       ph);

    plugin_handle->execute_wire_transfer_cancel
      (plugin_handle->cls,
       eh);

    GNUNET_SCHEDULER_shutdown ();
  }
}


/**
 * Ask the bank to execute a wire transfer.
 */
void
execute_wire_transfer ()
{
  struct TALER_Amount a;
  struct TALER_WireTransferIdentifierRawP wtid;

  if (NULL == amount)
  {
    fprintf (stderr,
             "The option -a: AMOUNT, is mandatory.\n");
    GNUNET_SCHEDULER_shutdown ();
    return;
  }

  if (GNUNET_OK != TALER_string_to_amount (amount,
                                           &a))
  {
    fprintf (stderr,
             "Amount string incorrect.\n"); 
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  if (NULL == destination_account_url)
  {
    fprintf (stderr,
             "Please give destination"
             " account URL (--destination/-d)\n"); 
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  if (NULL == (ph = plugin_handle->prepare_wire_transfer
    (plugin_handle->cls,
     account_section,
     destination_account_url,
     &a,
     "http://exchange.example.com/",
     &wtid, /* Any value will do.  */
     prepare_cb,
     NULL)))
  {
    fprintf (stderr,
             "Could not prepare the wire transfer\n");
    GNUNET_SCHEDULER_shutdown ();
  }
}

/**
 * Ask the bank the list of transactions for the bank account
 * mentioned in the config section given by the user.
 */
void
execute_history ()
{
  size_t bin_len = 0;
  void *since_when_bin = NULL;

  if (NULL != since_when)
  {
    bin_len = (strlen (since_when) * 5) / 8;

    since_when_bin = GNUNET_malloc (bin_len);
    GNUNET_assert
      (GNUNET_OK == GNUNET_STRINGS_string_to_data
        (since_when,
         strlen (since_when),
         since_when_bin,
         bin_len));
  }

  if (NULL == plugin_handle->get_history
      (plugin_handle->cls,
       account_section,
       TALER_BANK_DIRECTION_BOTH,
       since_when_bin,
       bin_len,
       -10,
       history_cb,
       NULL))
  {
    fprintf (stderr,
             "Could not request the transaction history.\n");
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
}

/**
 * Gets executed upon shutdown.  Main duty is
 * wire-plugin unloading.
 *
 * @param cls closure.
 */
void
do_shutdown (void *cls)
{
  TALER_WIRE_plugin_unload (plugin_handle);
}

/**
 * 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 cfg configuration
 */
static void
run (void *cls,
     char *const *args,
     const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  if (NULL == account_section)
  {
    fprintf (stderr,
             "The option: -s ACCOUNT-SECTION, is mandatory.\n");
    return;
  }

  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string
      (cfg,
       account_section,
       "plugin",
       &plugin_name))
  {
    fprintf (stderr,
             "Could not find the 'plugin' value under %s\n",
             account_section);
    return;
  }

  plugin_handle = TALER_WIRE_plugin_load (cfg,
                                          plugin_name);
  if (NULL == plugin_handle)
  {
    fprintf (stderr,
             "Could not load the wire plugin\n");
    return;
  }

  if (GNUNET_YES == history)
    execute_history ();
  else if (GNUNET_YES == transfer)
    execute_wire_transfer ();
  else
    fprintf (stderr,
           "Please give either --history/-H or --transfer/t\n");

  GNUNET_SCHEDULER_add_shutdown (&do_shutdown,
                                 NULL);
}

/**
 * Main function of taler-wire.  This tool is used to command the
 * execution of wire transfers from the command line.  Its main
 * purpose is to test whether the bank and exchange can speak the
 * same protocol of a certain wire plugin.
 *
 * @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_flag ('H',
                               "history",
                               "Ask to get a list of 10"
                               " transactions.",
                               &history),

    GNUNET_GETOPT_option_flag ('t',
                               "transfer",
                               "Execute a wire transfer.",
                               &transfer),

    GNUNET_GETOPT_option_string ('w',
                                 "since-when",
                                 "SW",
                                 "When asking the bank for"
                                 " transactions history, this"
                                 " option commands that all the"
                                 " results should have IDs settled"
                                 " after SW.  If not given, then"
                                 " the 10 youngest transactions"
                                 " are returned.",
                                 &since_when),

    GNUNET_GETOPT_option_string ('s',
                                 "section",
                                 "ACCOUNT-SECTION",
                                 "Which config section has the"
                                 " credentials to access the"
                                 " bank.  Mandatory.\n",
                                 &account_section),

    GNUNET_GETOPT_option_string ('a',
                                 "amount",
                                 "AMOUNT",
                                 "Specify the amount to transfer.",
                                 &amount),

    GNUNET_GETOPT_option_string ('d',
                                 "destination",
                                 "PAYTO-URL",
                                 "Destination account for the"
                                 " wire transfer.",
                                 &destination_account_url),
    GNUNET_GETOPT_OPTION_END
  };

  GNUNET_assert
    (GNUNET_OK == GNUNET_log_setup ("taler-wire",
                                    "WARNING",
                                    NULL)); /* filename */
  GNUNET_PROGRAM_run
    (argc,
     argv,
     "taler-wire",
     "CLI bank client.",
     options,
     &run,
     NULL);

  return global_ret;
}