/*
     This file is part of libmicrohttpd
     Copyright (C) 2016 Christian Grothoff

     libmicrohttpd 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 2, or (at your
     option) any later version.

     libmicrohttpd 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 libmicrohttpd; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
*/

/**
 * @file test_upgrade_common.c
 * @brief Shared logic for testcases for libmicrohttpd upgrading a connection
 * @author Christian Grothoff
 */


/**
 * Thread we use to run the interaction with the upgraded socket.
 */
static pthread_t pt;

/**
 * Will be set to the upgraded socket.
 */
static MHD_socket usock;

/**
 * Thread we use to run the interaction with the upgraded socket.
 */
static pthread_t pt_client;

/**
 * Flag set to 1 once the test is finished.
 */
static int done;

/**
 * Change itc FD options to be non-blocking.
 *
 * @param fd the FD to manipulate
 * @return non-zero if succeeded, zero otherwise
 */
static void
make_blocking (MHD_socket fd)
{
  int flags;

  flags = fcntl (fd, F_GETFL);
  if (-1 == flags)
    return;
  if ((flags & ~O_NONBLOCK) != flags)
    if (-1 == fcntl (fd, F_SETFL, flags & ~O_NONBLOCK))
      abort ();
}


static void
send_all (MHD_socket sock,
          const char *text)
{
  size_t len = strlen (text);
  ssize_t ret;

  make_blocking (sock);
  for (size_t off = 0; off < len; off += ret)
    {
      ret = write (sock,
                   &text[off],
                   len - off);
      if (-1 == ret)
        {
          if (EAGAIN == errno)
            {
              ret = 0;
              continue;
            }
          abort ();
        }
    }
}


/**
 * Read character-by-character until we
 * get '\r\n\r\n'.
 */
static void
recv_hdr (MHD_socket sock)
{
  unsigned int i;
  char next;
  char c;
  ssize_t ret;

  make_blocking (sock);
  next = '\r';
  i = 0;
  while (i < 4)
    {
      ret = read (sock,
                  &c,
                  1);
      if (-1 == ret)
        {
          if (EAGAIN == errno)
            {
              ret = 0;
              continue;
            }
          abort ();
        }
      if (0 == ret)
        continue;
      if (c == next)
        {
          i++;
          if (next == '\r')
            next = '\n';
          else
            next = '\r';
          continue;
        }
      if (c == '\r')
        {
          i = 1;
          next = '\n';
          continue;
        }
      i = 0;
      next = '\r';
    }
}


static void
recv_all (MHD_socket sock,
          const char *text)
{
  size_t len = strlen (text);
  char buf[len];
  ssize_t ret;

  make_blocking (sock);
  for (size_t off = 0; off < len; off += ret)
    {
      ret = read (sock,
                  &buf[off],
                  len - off);
      if (-1 == ret)
        {
          if (EAGAIN == errno)
            {
              ret = 0;
              continue;
            }
          abort ();
        }
    }
  if (0 != strncmp (text, buf, len))
    abort();
}


/**
 * Main function for the thread that runs the interaction with
 * the upgraded socket.
 *
 * @param cls the handle for the upgrade
 */
static void *
run_usock (void *cls)
{
  struct MHD_UpgradeResponseHandle *urh = cls;

  send_all (usock,
            "Hello");
  recv_all (usock,
            "World");
  send_all (usock,
            "Finished");
  MHD_upgrade_action (urh,
                      MHD_UPGRADE_ACTION_CLOSE);
  return NULL;
}


/**
 * Main function for the thread that runs the client-side of the
 * interaction with the upgraded socket.
 *
 * @param cls the client socket
 */
static void *
run_usock_client (void *cls)
{
  MHD_socket *sock = cls;

  send_all (*sock,
            "GET / HTTP/1.1\r\nConnection: Upgrade\r\n\r\n");
  recv_hdr (*sock);
  recv_all (*sock,
            "Hello");
  send_all (*sock,
            "World");
  recv_all (*sock,
            "Finished");
  MHD_socket_close_ (*sock);
  done = 1;
  return NULL;
}


/**
 * Function called after a protocol "upgrade" response was sent
 * successfully and the socket should now be controlled by some
 * protocol other than HTTP.
 *
 * Any data received on the socket will be made available in
 * 'data_in'.  The function should update 'data_in_size' to
 * reflect the number of bytes consumed from 'data_in' (the remaining
 * bytes will be made available in the next call to the handler).
 *
 * Any data that should be transmitted on the socket should be
 * stored in 'data_out'.  '*data_out_size' is initially set to
 * the available buffer space in 'data_out'.  It should be set to
 * the number of bytes stored in 'data_out' (which can be zero).
 *
 * The return value is a BITMASK that indicates how the function
 * intends to interact with the event loop.  It can request to be
 * notified for reading, writing, request to UNCORK the send buffer
 * (which MHD is allowed to ignore, if it is not possible to uncork on
 * the local platform), to wait for the 'external' select loop to
 * trigger another round.  It is also possible to specify "no events"
 * to terminate the connection; in this case, the
 * #MHD_RequestCompletedCallback will be called and all resources of
 * the connection will be released.
 *
 * Except when in 'thread-per-connection' mode, implementations
 * of this function should never block (as it will still be called
 * from within the main event loop).
 *
 * @param cls closure, whatever was given to #MHD_create_response_for_upgrade().
 * @param connection original HTTP connection handle,
 *                   giving the function a last chance
 *                   to inspect the original HTTP request
 * @param con_cls last value left in `*con_cls` in the `MHD_AccessHandlerCallback`
 * @param extra_in if we happened to have read bytes after the
 *                 HTTP header already (because the client sent
 *                 more than the HTTP header of the request before
 *                 we sent the upgrade response),
 *                 these are the extra bytes already read from @a sock
 *                 by MHD.  The application should treat these as if
 *                 it had read them from @a sock.
 * @param extra_in_size number of bytes in @a extra_in
 * @param sock socket to use for bi-directional communication
 *        with the client.  For HTTPS, this may not be a socket
 *        that is directly connected to the client and thus certain
 *        operations (TCP-specific setsockopt(), getsockopt(), etc.)
 *        may not work as expected (as the socket could be from a
 *        socketpair() or a TCP-loopback)
 * @param urh argument for #MHD_upgrade_action()s on this @a connection.
 *        Applications must eventually use this function to perform the
 *        close() action on the @a sock.
 */
static void
upgrade_cb (void *cls,
            struct MHD_Connection *connection,
            void *con_cls,
            const char *extra_in,
            size_t extra_in_size,
            MHD_socket sock,
            struct MHD_UpgradeResponseHandle *urh)
{
  usock = sock;
  if (0 != extra_in_size)
    abort ();
  pthread_create (&pt,
                  NULL,
                  &run_usock,
                  urh);
}


/**
 * A client has requested the given url using the given method
 * (#MHD_HTTP_METHOD_GET, #MHD_HTTP_METHOD_PUT,
 * #MHD_HTTP_METHOD_DELETE, #MHD_HTTP_METHOD_POST, etc).  The callback
 * must call MHD callbacks to provide content to give back to the
 * client and return an HTTP status code (i.e. #MHD_HTTP_OK,
 * #MHD_HTTP_NOT_FOUND, etc.).
 *
 * @param cls argument given together with the function
 *        pointer when the handler was registered with MHD
 * @param url the requested url
 * @param method the HTTP method used (#MHD_HTTP_METHOD_GET,
 *        #MHD_HTTP_METHOD_PUT, etc.)
 * @param version the HTTP version string (i.e.
 *        #MHD_HTTP_VERSION_1_1)
 * @param upload_data the data being uploaded (excluding HEADERS,
 *        for a POST that fits into memory and that is encoded
 *        with a supported encoding, the POST data will NOT be
 *        given in upload_data and is instead available as
 *        part of #MHD_get_connection_values; very large POST
 *        data *will* be made available incrementally in
 *        @a upload_data)
 * @param upload_data_size set initially to the size of the
 *        @a upload_data provided; the method must update this
 *        value to the number of bytes NOT processed;
 * @param con_cls pointer that the callback can set to some
 *        address and that will be preserved by MHD for future
 *        calls for this request; since the access handler may
 *        be called many times (i.e., for a PUT/POST operation
 *        with plenty of upload data) this allows the application
 *        to easily associate some request-specific state.
 *        If necessary, this state can be cleaned up in the
 *        global #MHD_RequestCompletedCallback (which
 *        can be set with the #MHD_OPTION_NOTIFY_COMPLETED).
 *        Initially, `*con_cls` will be NULL.
 * @return #MHD_YES if the connection was handled successfully,
 *         #MHD_NO if the socket must be closed due to a serios
 *         error while handling the request
 */
static int
ahc_upgrade (void *cls,
             struct MHD_Connection *connection,
             const char *url,
             const char *method,
             const char *version,
             const char *upload_data,
             size_t *upload_data_size,
             void **con_cls)
{
  struct MHD_Response *resp;
  int ret;

  resp = MHD_create_response_for_upgrade (&upgrade_cb,
                                          NULL);
  MHD_add_response_header (resp,
                           MHD_HTTP_HEADER_UPGRADE,
                           "Hello World Protocol");
  ret = MHD_queue_response (connection,
                            MHD_HTTP_SWITCHING_PROTOCOLS,
                            resp);
  MHD_destroy_response (resp);
  return ret;
}


/**
 * Run the MHD external event loop using select.
 *
 * @param daemon daemon to run it for
 * @param flags the flags the daemon was started with
 */
static void
run_mhd_select_loop (struct MHD_Daemon *daemon)
{
  fd_set rs;
  fd_set ws;
  fd_set es;
  MHD_socket max_fd;
  MHD_UNSIGNED_LONG_LONG to;
  struct timeval tv;

  while (! done)
    {
      FD_ZERO (&rs);
      FD_ZERO (&ws);
      FD_ZERO (&es);
      max_fd = -1;
      to = 1000;

      if (MHD_YES !=
          MHD_get_fdset (daemon,
                         &rs,
                         &ws,
                         &es,
                         &max_fd))
        abort ();
      MHD_get_timeout (daemon,
                       &to);
      tv.tv_sec = to / 1000;
      tv.tv_usec = 1000 * (to % 1000);
      select (max_fd + 1,
              &rs,
              &ws,
              &es,
              &tv);
      MHD_run_from_select (daemon,
                           &rs,
                           &ws,
                           &es);
    }
}


/**
 * Run the MHD external event loop using select.
 *
 * @param daemon daemon to run it for
 * @param flags the flags the daemon was started with
 */
static void
run_mhd_poll_loop (struct MHD_Daemon *daemon)
{
  abort (); /* currently not implementable with existing MHD API */
}


/**
 * Run the MHD external event loop using select.
 *
 * @param daemon daemon to run it for
 * @param flags the flags the daemon was started with
 */
static void
run_mhd_epoll_loop (struct MHD_Daemon *daemon)
{
  const union MHD_DaemonInfo *di;
  MHD_socket ep;
  fd_set rs;
  MHD_UNSIGNED_LONG_LONG to;
  struct timeval tv;

  di = MHD_get_daemon_info (daemon,
                            MHD_DAEMON_INFO_EPOLL_FD);
  ep = di->listen_fd;
  while (! done)
    {
      FD_ZERO (&rs);
      to = 1000;

      FD_SET (ep, &rs);
      MHD_get_timeout (daemon,
                       &to);
      tv.tv_sec = to / 1000;
      tv.tv_usec = 1000 * (to % 1000);
      select (ep + 1,
              &rs,
              NULL,
              NULL,
              &tv);
      MHD_run (daemon);
    }
}


/**
 * Run the MHD external event loop using select.
 *
 * @param daemon daemon to run it for
 * @param flags the flags the daemon was started with
 */
static void
run_mhd_loop (struct MHD_Daemon *daemon,
              int flags)
{
  if (0 != (flags & MHD_USE_POLL))
    run_mhd_poll_loop (daemon);
#if EPOLL_SUPPORT
  else if (0 != (flags & MHD_USE_EPOLL))
    run_mhd_epoll_loop (daemon);
#endif
  else
    run_mhd_select_loop (daemon);
}