/*
  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 Lesser General Public License as published by the Free Software
  Foundation; either version 2.1, 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 Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License along with
  TALER; see the file COPYING.LGPL.  If not, see
  <http://www.gnu.org/licenses/>
*/
/**
 * @file merchant_api_common.c
 * @brief Implementation of common logic for libtalermerchant
 * @author Christian Grothoff
 */
#include "platform.h"
#include <curl/curl.h>
#include <jansson.h>
#include <microhttpd.h> /* just for HTTP status codes */
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_uri_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_merchant_service.h"
#include <taler/taler_json_lib.h>


void
TALER_MERCHANT_parse_error_details_ (const json_t *response,
                                     unsigned int http_status,
                                     struct TALER_MERCHANT_HttpResponse *hr)
{
  const json_t *jc;

  memset (hr, 0, sizeof (*hr));
  hr->reply = response;
  hr->http_status = http_status;
  if (NULL == response)
  {
    hr->ec = TALER_EC_GENERIC_INVALID_RESPONSE;
    return;
  }
  hr->ec = TALER_JSON_get_error_code (response);
  hr->hint = TALER_JSON_get_error_hint (response);

  /* handle 'exchange_http_status' */
  jc = json_object_get (response,
                        "exchange_http_status");
  /* The caller already knows that the JSON represents an error,
     so we are dealing with a missing error code here.  */
  if (NULL == jc)
    return; /* no need to bother with exchange_code/hint if we had no status */
  if (! json_is_integer (jc))
  {
    GNUNET_break_op (0);
    return;
  }
  hr->exchange_http_status = (unsigned int) json_integer_value (jc);

  /* handle 'exchange_reply' */
  jc = json_object_get (response,
                        "exchange_reply");
  if (! json_is_object (jc))
  {
    GNUNET_break_op (0);
  }
  else
  {
    hr->exchange_reply = jc;
  }

  /* handle 'exchange_code' */
  jc = json_object_get (response,
                        "exchange_code");
  /* The caller already knows that the JSON represents an error,
     so we are dealing with a missing error code here.  */
  if (NULL == jc)
    return; /* no need to bother with exchange-hint if we had no code */
  if (! json_is_integer (jc))
  {
    GNUNET_break_op (0);
    hr->exchange_code = TALER_EC_INVALID;
  }
  else
  {
    hr->exchange_code = (enum TALER_ErrorCode) json_integer_value (jc);
  }

  /* handle 'exchange-hint' */
  jc = json_object_get (response,
                        "exchange-hint");
  /* The caller already knows that the JSON represents an error,
     so we are dealing with a missing error code here.  */
  if (NULL == jc)
    return;
  if (! json_is_string (jc))
  {
    GNUNET_break_op (0);
  }
  else
  {
    hr->exchange_hint = json_string_value (jc);
  }
}


char *
TALER_MERCHANT_baseurl_add_instance (const char *base_url,
                                     const char *instance_id)
{
  char *ret;
  bool end_sl;

  if ('\0' == *base_url)
  {
    GNUNET_break (0);
    return NULL;
  }
  end_sl = '/' == base_url[strlen (base_url) - 1];

  GNUNET_asprintf (&ret,
                   (end_sl)
                   ? "%sinstances/%s/"
                   : "%s/instances/%s/",
                   base_url,
                   instance_id);
  return ret;
}


int
TALER_MERCHANT_parse_pay_uri (const char *pay_uri,
                              struct TALER_MERCHANT_PayUriData *parse_data)
{
  char *cp = GNUNET_strdup (pay_uri);
  struct GNUNET_Uri u;

  if (0 !=
      GNUNET_uri_parse (&u,
                        cp))
  {
    GNUNET_free (cp);
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  if ((0 != strcasecmp ("taler",
                        u.scheme)) &&
      (0 != strcasecmp ("taler+http",
                        u.scheme)))
  {
    fprintf (stderr,
             "Bad schema %s\n",
             u.scheme);
    GNUNET_free (cp);
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  parse_data->use_http = (0 == strcasecmp ("taler+http",
                                           u.scheme));
  if (0 != strcasecmp ("pay",
                       u.host))
  {
    GNUNET_break_op (0);
    GNUNET_free (cp);
    return GNUNET_SYSERR;
  }

  {
    char *order_id;
    char *mpp;
    char *session_id = strrchr (u.path,
                                '/');
    struct TALER_ClaimTokenP *claim_token = NULL;

    if (NULL == session_id)
    {
      GNUNET_break_op (0);
      GNUNET_free (cp);
      return GNUNET_SYSERR;
    }
    *session_id = '\0';
    ++session_id;

    order_id = strrchr (u.path,
                        '/');
    if (NULL == order_id)
    {
      GNUNET_break_op (0);
      GNUNET_free (cp);
      return GNUNET_SYSERR;
    }
    *order_id = '\0';
    ++order_id;
    mpp = strchr (u.path,
                  '/');
    if (NULL != mpp)
    {
      *mpp = '\0';
      ++mpp;
    }

    {
      char *ct_str = u.query;
      char *ct_data;

      if (NULL != ct_str)
      {
        ct_data = strchr (u.query,
                          '=');
        if (NULL == ct_data)
        {
          GNUNET_break_op (0);
          GNUNET_free (cp);
          return GNUNET_SYSERR;
        }
        *ct_data = '\0';
        ++ct_data;
        claim_token = GNUNET_new (struct TALER_ClaimTokenP);
        if ( (0 != strcmp ("c",
                           u.query)) ||
             (GNUNET_OK !=
              GNUNET_STRINGS_string_to_data (ct_data,
                                             strlen (ct_data),
                                             claim_token,
                                             sizeof (*claim_token))) )
        {
          GNUNET_break_op (0);
          GNUNET_free (claim_token);
          GNUNET_free (cp);
          return GNUNET_SYSERR;
        }
      }
    }

    parse_data->merchant_prefix_path
      = (NULL == mpp)
        ? NULL
        : GNUNET_strdup (mpp);
    parse_data->merchant_host = GNUNET_strdup (u.path);
    parse_data->order_id = GNUNET_strdup (order_id);
    parse_data->session_id
      = (0 < strlen (session_id))
        ? GNUNET_strdup (session_id)
        : NULL;
    parse_data->claim_token = claim_token;
    parse_data->ssid
      = (NULL == u.fragment)
        ? NULL
        : GNUNET_strdup (u.fragment);
  }
  GNUNET_free (cp);
  return GNUNET_OK;
}


void
TALER_MERCHANT_parse_pay_uri_free (
  struct TALER_MERCHANT_PayUriData *parse_data)
{
  GNUNET_free (parse_data->merchant_host);
  GNUNET_free (parse_data->merchant_prefix_path);
  GNUNET_free (parse_data->order_id);
  GNUNET_free (parse_data->session_id);
  GNUNET_free (parse_data->claim_token);
  GNUNET_free (parse_data->ssid);
}


int
TALER_MERCHANT_parse_refund_uri (
  const char *refund_uri,
  struct TALER_MERCHANT_RefundUriData *parse_data)
{
  char *cp = GNUNET_strdup (refund_uri);
  struct GNUNET_Uri u;

  if (0 !=
      GNUNET_uri_parse (&u,
                        cp))
  {
    GNUNET_free (cp);
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  if ((0 != strcasecmp ("taler",
                        u.scheme)) &&
      (0 != strcasecmp ("taler+http",
                        u.scheme)))
  {
    GNUNET_free (cp);
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  parse_data->use_http = (0 == strcasecmp ("taler+http",
                                           u.scheme));

  if (0 != strcasecmp ("refund",
                       u.host))
  {
    GNUNET_break_op (0);
    GNUNET_free (cp);
    return GNUNET_SYSERR;
  }

  {
    char *order_id;
    char *last_seg = strrchr (u.path,
                              '/');

    if (NULL == last_seg)
    {
      GNUNET_break_op (0);
      GNUNET_free (cp);
      return GNUNET_SYSERR;
    }
    *last_seg = '\0';
    ++last_seg;

    order_id = strrchr (u.path,
                        '/');
    if (NULL == order_id)
    {
      GNUNET_break_op (0);
      GNUNET_free (cp);
      return GNUNET_SYSERR;
    }
    *order_id = '\0';
    ++order_id;
    if (0 != strlen (last_seg))
    {
      GNUNET_break_op (0);
      GNUNET_free (cp);
      return GNUNET_SYSERR;
    }

    {
      char *mpp;

      mpp = strchr (u.path,
                    '/');
      if (NULL != mpp)
      {
        *mpp = '\0';
        ++mpp;
      }

      parse_data->merchant_prefix_path
        = (NULL == mpp)
          ? NULL
          : GNUNET_strdup (mpp);
    }
    parse_data->merchant_host = GNUNET_strdup (u.path);
    parse_data->order_id = GNUNET_strdup (order_id);
    parse_data->ssid
      = (NULL == u.fragment)
        ? NULL
        : GNUNET_strdup (u.fragment);
  }
  GNUNET_free (cp);
  return GNUNET_OK;
}


void
TALER_MERCHANT_parse_refund_uri_free (
  struct TALER_MERCHANT_RefundUriData *parse_data)
{
  GNUNET_free (parse_data->merchant_host);
  GNUNET_free (parse_data->merchant_prefix_path);
  GNUNET_free (parse_data->order_id);
  GNUNET_free (parse_data->ssid);
}