/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 *
 * Copyright (©) 2005,2006,2007,2008,2009,2010,2011,2012 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 *
 * Deliantra is free software: you can redistribute it and/or modify it under
 * the terms of the Affero GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program 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 Affero GNU General Public License
 * and the GNU General Public License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

/*
 * Socket general functions
 */

#include <global.h>
#include <sproto.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netinet/ip.h>
#include <netdb.h>

#include <unistd.h>
#include <arpa/inet.h>

#include <algorithm>

// use relatively small values, as we do not expect to receive much,
// and we do userspace write buffering
// 8kb limits throughput to roughly 66kb/s
#define SOCKET_RCVBUF  8192
#define SOCKET_SNDBUF 16384

sockvec clients;

/**
 * Initializes a connection. Really, it just sets up the data structure,
 * socket setup is handled elsewhere.  We do send a version to the
 * client.
 */
client::client (int fd, const char *peername)
: fd (fd), host (strdup (peername)),
  socket_ev (this, &client::socket_cb)
{
  refcnt_inc (); // the socket is an external reference

  mss = 1500 - 52; // 1500 typical ethernet frame, 66 typical tcp header overhead

  socket_timeout = 16.;

  {
    struct linger linger_opt;

    linger_opt.l_onoff  = 0;
    linger_opt.l_linger = 0;

    if (setsockopt (fd, SOL_SOCKET, SO_LINGER, &linger_opt, sizeof (struct linger)))
      LOG (llevError, "SO_LINGER: %s\n", strerror (errno));
  }

  {
    int val;

#ifdef SO_RCVBUF
    val = SOCKET_RCVBUF;
    if (setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &val, sizeof (val)))
      LOG (llevError, "SO_RCVBUF: %s\n", strerror (errno));
#endif

#ifdef SO_SNDBUF
    val = SOCKET_SNDBUF;
    if (setsockopt (fd, SOL_SOCKET, SO_SNDBUF, &val, sizeof (val)))
      LOG (llevError, "SO_SNDBUF: %s\n", strerror (errno));
#endif

#ifdef IP_TOS
    val = IPTOS_LOWDELAY;
    if (setsockopt (fd, IPPROTO_IP, IP_TOS, &val, sizeof (val)))
      LOG (llevError, "IP_TOS: %s\n", strerror (errno));
#endif

#ifdef TCP_NODELAY
    val = 1;
    if (setsockopt (fd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof (val)))
      LOG (llevError, "TCP_NODELAY: %s\n", strerror (errno));
#endif

    // set some very aggressive keepalive parameters
#ifdef TCP_KEEPIDLE
    val = 1;
    if (setsockopt (fd, IPPROTO_TCP, TCP_KEEPIDLE, &val, sizeof (val)))
      LOG (llevError, "TCP_KEEPIDLE: %s\n", strerror (errno));
#endif

#ifdef TCP_KEEPCNT
    val = 3;
    if (setsockopt (fd, IPPROTO_TCP, TCP_KEEPCNT, &val, sizeof (val)))
      LOG (llevError, "TCP_KEEPCNT: %s\n", strerror (errno));
#endif

#ifdef TCP_KEEPINTVL
    val = 1;
    if (setsockopt (fd, IPPROTO_TCP, TCP_KEEPINTVL, &val, sizeof (val)))
      LOG (llevError, "TCP_KEEPINTVL: %s\n", strerror (errno));
#endif

    // try to find the mss value in use
#ifdef TCP_MAXSEG
    socklen_t sl = sizeof (val);
    if (!getsockopt (fd, IPPROTO_TCP, TCP_MAXSEG, &val, &sl) && sl == sizeof (val))
      mss = val;
#endif
  }

  if (fcntl (fd, F_SETFL, O_NONBLOCK) == -1)
    LOG (llevError, "InitConnection:  Error on fcntl.\n");

  state = ST_SETUP;
  mapx = 11;
  mapy = 11;
  itemcmd = 1;              /* Default is version item1 command */
  max_rate = 100000 / (1000000 / MAX_TIME); // ~1mbit is assumed per default

  /* Do this so we don't send a face command for the client for
   * this face.  Face 0 is sent to the client to say clear
   * face information.
   */
  faces_sent[0] = true;
  fx_want [FT_FACE] = true; // all clients must support image faces

  socket_ev.set (fd, EV_READ);
  socket_ev.prio (2); // one higher than the ticker priority
  socket_ev.start ();

  // initialisation done, kick it!
  INVOKE_CLIENT (CONNECT, this);

  flush ();

  reset_stats ();

  clients.insert (this);
}

client::~client ()
{
  clients.erase (this);

  mapinfo_queue_clear ();
  free (stats.range);
  free (stats.title);
  free (host);
}

void
client::do_destroy ()
{
  INVOKE_CLIENT (CLIENT_DESTROY, this);
  attachable::do_destroy ();

  if (pl)
    pl->disconnect ();

  if (fd >= 0)
    {
      send_packet ("goodbye");
      flush ();

      close (fd);
    }

  state = ST_DEAD;

  socket_ev.stop ();

  refcnt_dec (); // socket no longer open
}

void
client::reset_stats ()
{
  /* we need to clear these to -1 and not zero - otherwise,
   * if a player quits and starts a new character, we wont
   * send new values to the client, as things like exp start
   * at zero.
   */
  for (int i = 0; i < array_length (last_skill_exp); i++)
    last_skill_exp[i] = -1;

  for (int i = 0; i < array_length (last_resist); i++)
    last_resist[i] = -1;

  last_weapon_sp     = -1;
  last_level         = -1;
  last_stats.exp     = -1;
  last_flags         = 0;
  last_weight        = -1;
  last_weight_limit  = 0;
  last_path_attuned  = 0;
  last_path_repelled = 0;
  last_path_denied   = 0;
  last_speed         = 0;
  last_flags         = 0;

  static living zero_living;
  last_stats = zero_living;
}

client *
client::create (int fd, const char *peername)
{
  client *ns = new client (dup (fd), peername);

  ns->instantiate (); // effectively a nop right now

  return ns;
}