/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997 Jukka Santala (Donwulff)
 *  Copyright (c) 2000-2018 ircd-hybrid development team
 *
 *  This program 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 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 GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 *  USA
 */

/*! \file m_watch.c
 * \brief Includes required functions for processing the WATCH command.
 * \version $Id: m_watch.c 8436 2018-03-29 09:04:53Z michael $
 */

#include "stdinc.h"
#include "client.h"
#include "irc_string.h"
#include "ircd.h"
#include "numeric.h"
#include "conf.h"
#include "send.h"
#include "parse.h"
#include "modules.h"
#include "user.h"
#include "watch.h"
#include "isupport.h"


/*
 * RPL_NOWON        - Online at the moment (Succesfully added to WATCH-list)
 * RPL_NOWOFF       - Offline at the moment (Succesfully added to WATCH-list)
 * RPL_WATCHOFF     - Succesfully removed from WATCH-list.
 * ERR_TOOMANYWATCH - Take a guess :>  Too many WATCH entries.
 */
static void
show_watch(struct Client *source_p, const char *name,
           enum irc_numerics rpl1, enum irc_numerics rpl2)
{
  const struct Client *target_p;

  if ((target_p = find_person(source_p, name)))
    sendto_one_numeric(source_p, &me, rpl1,
                       target_p->name, target_p->username,
                       target_p->host, target_p->tsinfo);
  else
    sendto_one_numeric(source_p, &me, rpl2, name, "*", "*", 0);
}

/*! \brief WATCH command handler
 *
 * \param source_p Pointer to allocated Client struct from which the message
 *                 originally comes from.  This can be a local or remote client.
 * \param parc     Integer holding the number of supplied arguments.
 * \param parv     Argument vector where parv[0] .. parv[parc-1] are non-NULL
 *                 pointers.
 * \note Valid arguments for this command are:
 *      - parv[0] = command
 *      - parv[1] = watch options
 */
static int
m_watch(struct Client *source_p, int parc, char *parv[])
{
  dlink_node *node;
  char *p = NULL;
  char def[2] = "l";
  unsigned int list_requested = 0;

  /*
   * Default to 'l' - list who's currently online
   */
  if (parc < 2)
    parv[1] = def;

  for (char *s = strtok_r(parv[1], ", ", &p); s;
             s = strtok_r(NULL,    ", ", &p))
  {
    char *user;
    if ((user = strchr(s, '!')))
      *user = '\0'; /* Not used */

    /*
     * Prefix of "+", they want to add a name to their WATCH list.
     */
    if (*s == '+')
    {
      if (*(s + 1))
      {
        if (dlink_list_length(&source_p->connection->watches) >=
            ConfigGeneral.max_watch)
        {
          sendto_one_numeric(source_p, &me, ERR_TOOMANYWATCH, s + 1, ConfigGeneral.max_watch);
          continue;
        }

        if (valid_nickname(s + 1, 1))
          watch_add_to_hash_table(s + 1, source_p);
      }

      show_watch(source_p, s + 1, RPL_NOWON, RPL_NOWOFF);
      continue;
    }

    /*
     * Prefix of "-", coward wants to remove somebody from their
     * WATCH list.  So do it. :-)
     */
    if (*s == '-')
    {
      watch_del_from_hash_table(s + 1, source_p);
      show_watch(source_p, s + 1, RPL_WATCHOFF, RPL_WATCHOFF);
      continue;
    }

    /*
     * Fancy "C" or "c", they want to nuke their WATCH list and start
     * over, so be it.
     */
    if (*s == 'C' || *s == 'c')
    {
      watch_del_watch_list(source_p);
      continue;
    }

    /*
     * Now comes the fun stuff, "S" or "s" returns a status report of
     * their WATCH list. I imagine this could be CPU intensive if
     * it's done alot, perhaps an auto-lag on this?
     */
    if (*s == 'S' || *s == 's')
    {
      char buf[IRCD_BUFSIZE] = "";
      unsigned int count = 0;

      if (list_requested & 0x1)
        continue;

      list_requested |= 0x1;

      /*
       * Send a list of how many users they have on their WATCH list
       * and how many WATCH lists they are on.
       */
      const struct Watch *watch;
      if ((watch = watch_find_hash(source_p->name)))
        count = dlink_list_length(&watch->watched_by);

      sendto_one_numeric(source_p, &me, RPL_WATCHSTAT,
                 dlink_list_length(&source_p->connection->watches), count);

      /*
       * Send a list of everybody in their WATCH list. Be careful
       * not to buffer overflow.
       */
      if ((node = source_p->connection->watches.head) == NULL)
      {
        sendto_one_numeric(source_p, &me, RPL_ENDOFWATCHLIST, *s);
        continue;
      }

      watch = node->data;
      strlcpy(buf, watch->name, sizeof(buf));

      count = strlen(source_p->name) + strlen(me.name) + 10 + strlen(buf);

      while ((node = node->next))
      {
        watch = node->data;

        if (count + strlen(watch->name) + 1 > IRCD_BUFSIZE - 2)
        {
          sendto_one_numeric(source_p, &me, RPL_WATCHLIST, buf);
          buf[0] = '\0';
          count = strlen(source_p->name) + strlen(me.name) + 10;
        }

        strlcat(buf, " ", sizeof(buf));
        strlcat(buf, watch->name, sizeof(buf));
        count += strlen(watch->name) + 1;
      }

      sendto_one_numeric(source_p, &me, RPL_WATCHLIST, buf);
      sendto_one_numeric(source_p, &me, RPL_ENDOFWATCHLIST, *s);
      continue;
    }

    /*
     * Well that was fun, NOT.  Now they want a list of everybody in
     * their WATCH list AND if they are online or offline? Sheesh,
     * greedy aren't we?
     */
    if (*s == 'L' || *s == 'l')
    {
      if (list_requested & 0x2)
        continue;

      list_requested |= 0x2;

      DLINK_FOREACH(node, source_p->connection->watches.head)
      {
        const struct Watch *watch = node->data;
        const struct Client *target_p;

        if ((target_p = find_person(source_p, watch->name)))
          sendto_one_numeric(source_p, &me, RPL_NOWON,
                             target_p->name, target_p->username,
                             target_p->host, target_p->tsinfo);

        /*
         * But actually, only show them offline if it's a capital
         * 'L' (full list wanted).
         */
        else if (*s == 'L')
          sendto_one_numeric(source_p, &me, RPL_NOWOFF, watch->name,
                             "*", "*", watch->lasttime);
      }

      sendto_one_numeric(source_p, &me, RPL_ENDOFWATCHLIST, *s);
      continue;
    }

    /* Hmm.. unknown prefix character.. Ignore it. :-) */
  }

  return 0;
}

static struct Message watch_msgtab =
{
  .cmd = "WATCH",
  .args_max = 1,
  .handlers[UNREGISTERED_HANDLER] = m_unregistered,
  .handlers[CLIENT_HANDLER] = m_watch,
  .handlers[SERVER_HANDLER] = m_ignore,
  .handlers[ENCAP_HANDLER] = m_ignore,
  .handlers[OPER_HANDLER] = m_watch
};

static void
module_init(void)
{
  mod_add_cmd(&watch_msgtab);
  isupport_add("WATCH", NULL, ConfigGeneral.max_watch);
}

static void
module_exit(void)
{
  mod_del_cmd(&watch_msgtab);
  isupport_delete("WATCH");
}

struct module module_entry =
{
  .version = "$Revision: 8436 $",
  .modinit = module_init,
  .modexit = module_exit,
};