/*
  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 taler-merchant-httpd_spa.c
 * @brief logic to load the single page app (/)
 * @author Christian Grothoff
 */
#include "platform.h"
#include <gnunet/gnunet_util_lib.h>
#include <taler/taler_util.h>
#include <taler/taler_mhd_lib.h>
#include "taler-merchant-httpd_statics.h"
#include <gnunet/gnunet_mhd_compat.h>


/**
 * SPA, compressed.
 */
static struct MHD_Response *zspa;

/**
 * SPA, vanilla.
 */
static struct MHD_Response *spa;


MHD_RESULT
TMH_return_spa (const struct TMH_RequestHandler *rh,
                struct MHD_Connection *connection,
                struct TMH_HandlerContext *hc)
{
  if ( (MHD_YES ==
        TALER_MHD_can_compress (connection)) &&
       (NULL != zspa) )
    return MHD_queue_response (connection,
                               MHD_HTTP_OK,
                               zspa);
  return MHD_queue_response (connection,
                             MHD_HTTP_OK,
                             spa);
}


int
TMH_spa_init ()
{
  char *dn;
  int fd;
  struct stat sb;

  {
    char *path;

    path = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_DATADIR);
    if (NULL == path)
    {
      GNUNET_break (0);
      return GNUNET_SYSERR;
    }
    GNUNET_asprintf (&dn,
                     "%s/merchant/spa/spa.html",
                     path);
    GNUNET_free (path);
  }

  /* finally open template */
  fd = open (dn,
             O_RDONLY);
  if (-1 == fd)
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                              "open",
                              dn);
    GNUNET_free (dn);
    return GNUNET_SYSERR;
  }
  if (0 !=
      fstat (fd,
             &sb))
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                              "open",
                              dn);
    GNUNET_break (0 == close (fd));
    GNUNET_free (dn);
    return GNUNET_SYSERR;
  }

  {
    void *in;
    ssize_t r;
    size_t csize;

    in = GNUNET_malloc_large (sb.st_size);
    if (NULL == in)
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
                           "malloc");
      GNUNET_break (0 == close (fd));
      GNUNET_free (dn);
      return GNUNET_SYSERR;
    }
    r = read (fd,
              in,
              sb.st_size);
    if ( (-1 == r) ||
         (sb.st_size != (size_t) r) )
    {
      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                                "read",
                                dn);
      GNUNET_free (in);
      GNUNET_break (0 == close (fd));
      GNUNET_free (dn);
      return GNUNET_SYSERR;
    }
    csize = (size_t) r;
    if (MHD_YES ==
        TALER_MHD_body_compress (&in,
                                 &csize))
    {
      zspa = MHD_create_response_from_buffer (csize,
                                              in,
                                              MHD_RESPMEM_MUST_FREE);
      if (NULL != zspa)
      {
        if (MHD_NO ==
            MHD_add_response_header (zspa,
                                     MHD_HTTP_HEADER_CONTENT_ENCODING,
                                     "deflate"))
        {
          GNUNET_break (0);
          MHD_destroy_response (zspa);
          zspa = NULL;
        }
        GNUNET_break (MHD_YES ==
                      MHD_add_response_header (zspa,
                                               MHD_HTTP_HEADER_CONTENT_TYPE,
                                               "text/html"));
      }
    }
    else
    {
      GNUNET_free (in);
    }
  }

  spa = MHD_create_response_from_fd (sb.st_size,
                                     fd);
  if (NULL == spa)
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                              "open",
                              dn);
    GNUNET_break (0 == close (fd));
    GNUNET_free (dn);
    if (NULL != zspa)
    {
      MHD_destroy_response (zspa);
      zspa = NULL;
    }
    return GNUNET_SYSERR;
  }
  GNUNET_free (dn);
  GNUNET_break (MHD_YES ==
                MHD_add_response_header (spa,
                                         MHD_HTTP_HEADER_CONTENT_TYPE,
                                         "text/html"));
  return GNUNET_OK;
}


/**
 * Nicely shut down.
 */
void __attribute__ ((destructor))
get_spa_fini ()
{
  if (NULL != spa)
  {
    MHD_destroy_response (spa);
    spa = NULL;
  }
  if (NULL != zspa)
  {
    MHD_destroy_response (zspa);
    zspa = NULL;
  }
}