/*       +------------------------------------+
 *       | Inspire Internet Relay Chat Daemon |
 *       +------------------------------------+
 *
 *  InspIRCd: (C) 2002-2010 InspIRCd Development Team
 * See: http://wiki.inspircd.org/Credits
 *
 * This program is free but copyrighted software; see
 *            the file COPYING for details.
 *
 * ---------------------------------------------------
 */


#include "inspircd.h"
#include "account.h"

/* $ModDesc: Provides channel mode +r for channel registration */

/* The last_activity extension item: last part from the channel, used to implement expiry */
class ChanExpiryExtItem : public ExtensionItem
{
	public:
	ChanExpiryExtItem (Module *owner) : ExtensionItem ("last_activity", owner)
	{

	}
	/* a function to get pointer to the timestamp for a given channel */
	time_t get (const Extensible *container) const
	{
		return reinterpret_cast<time_t> (get_raw (container));
	}
	void set (Extensible *container, time_t value)
	{
		set_raw (container, reinterpret_cast<void *> (value));
	}
	void unset (Extensible *container)
	{
		unset_raw (container);
	}
	void free (void *value)
	{
	}
	/* task of this function is to make the given string into the time_t and to put it in the extension item for the given container */
	void unserialize (SerializeFormat format, Extensible *container, const std::string &value)
	{
		/* independently of the format, the string is always the timestamp */
		/* if nothing happens, we are sure that no one will normally send the metadata except netburst */
		/* if this will be a netburst, we are sure no one will unset it, it just won't be send at all */
		/* so string can't be empty, and thus, the extension item's value can be not found, but can't be 0 */
		/* get the null terminated string from the std::string class, convert it to the integer/time_t */
		time_t newtime = atol (value.c_str ( ));
		/* if newtime is less or equal than the current time set then don't change */
		if (newtime <= get (container))
			return;
		/* if not */
		set (container, newtime);
	}
	std::string serialize (SerializeFormat format, const Extensible *container, void *item) const
	{
		/* we got a value, if it is null then return empty string to deny sending metadata */
		/* if it is not null, it's a pointer to time_t, so cast it, convert to string and return */
		if (!item) return "";
		time_t v = reinterpret_cast<time_t> (item);
		return ConvToStr (v);
	}
};

/* database reader reads the channel database and returns structure with it */
/* structure for single entry */
struct EntryDescriptor
{
	std::string name, ts, topicset, topicsetby, topic, modes, registrant;
};
class DatabaseReader
{
	/* the entry descriptor */
	EntryDescriptor entry;
	/* file */
	FILE *fd;
 public:
	/* constructor, opens the file */
	DatabaseReader (std::string filename)
	{
		/* initialize */
		fd = NULL;
		/* open the file */
		fd = fopen (filename.c_str ( ), "r");
		/* if we can't open the file, return. */
		if (!fd) return;
	}
	/* destructor will close the file */
	~DatabaseReader ( )
	{
		/* if fd is not null, close it */
		if (fd) fclose (fd);
	}
	/* get next entry */
	EntryDescriptor *next ( )
	{
		/* if fd is NULL, fake eof */
		if (!fd) return 0;
		/* clear data */
		entry.name = "";
		entry.ts = "";
		entry.registrant = "";
		entry.topicset = "";
		entry.topicsetby = "";
		entry.modes = "";
		entry.topic = "";
		std::string str;
		/* read single characters from the file and add them to the string, end at EOF or \n, ignore \r */
		while (1)
		{
			int c = fgetc (fd);
			if ((c == EOF) || ((unsigned char)c == '\n')) break;
			if ((unsigned char)c == '\r') continue;
			str.push_back ((unsigned char)c);
		}
		/* ready to parse the line */
		if (str == "") return 0;
		std::string token;
		irc::spacesepstream sep(str);
		/* get first one */
		bool res = sep.GetToken (token);
		/* malformed if it is not chaninfo */
		if (token != "chaninfo" || !res)
		{
			ServerInstance->Logs->Log ("MODULE", DEFAULT, "malformed channel database");
			return 0;
		}
		/* okay, read channel name */
		res = sep.GetToken (token);
		/* name was get, but if it's the last token, database is malformed */
		if (!res)
		{
			ServerInstance->Logs->Log ("MODULE", DEFAULT, "malformed channel database");
			return 0;
		}
		/* save name */
		entry.name = token;
		/* get next token, if it's the last one, db is malformed */
		res = sep.GetToken (token);
		if (!res)
		{
			ServerInstance->Logs->Log ("MODULE", DEFAULT, "malformed channel database");
			return 0;
		}
		/* set channel timestamp */
			entry.ts = token;
		/* get the last token */
		res = sep.GetToken (token);
		/* this time we ignore things after this token */
		/* set registrant */
		entry.registrant = token;
		/* initial entry read, read next lines in a loop until end, eof means malformed database again */
		while (1)
		{
			str.clear ( );
			/* read the line */
			while (1)
			{
				int c = fgetc (fd);
				if (c == EOF)
				{
					ServerInstance->Logs->Log ("MODULE", DEFAULT, "malformed channel database");
					return 0;
				}
					unsigned char c2 = (unsigned char)c;
				if (c2 == '\n') break;
				if (c2 == '\r') continue;
				str.push_back (c2);
			}
			irc::spacesepstream sep2(str);
			/* get the token */
			if (str == "")
			{
				ServerInstance->Logs->Log ("MODULE", DEFAULT, "malformed channel database");
				return 0;
			}
			res = sep2.GetToken (token);
			/* break the loop if token is "end" */
			if (token == "end") break;
			/* it is not, so the large if statement there */
			else if (token == "topic")
			{
				/* topic info, if end then it is malformed */
				if (sep2.StreamEnd ( ))
				{
					ServerInstance->Logs->Log ("MODULE", DEFAULT, "malformed topic declaration in channel database for channel %s", entry.name.c_str ( ));
				}
				/* if not, then read topic set time */
				res = sep2.GetToken (token);
				/* if end then malformed */
				if (!res)
				{
					ServerInstance->Logs->Log ("MODULE", DEFAULT, "malformed topic declaration in channel database for channel %s", entry.name.c_str ( ));
				}
				/* save that */
				entry.topicset = token;
				/* get next token */
				res = sep2.GetToken (token);
				/* if last then malformed */
				if (!res)
				{
					ServerInstance->Logs->Log ("MODULE", DEFAULT, "malformed topic declaration in channel database for channel %s", entry.name.c_str ( ));
				}
				entry.topicsetby = token;
				/* get rest of the declaration into the topic string, this is a topic */
				entry.topic = sep2.GetRemaining ( );
			} else if (token == "modes")
			{
				/* modes token, used for representing modes, it's the easier one, just load remaining data */
				if (sep2.StreamEnd ( ))
				{
					ServerInstance->Logs->Log ("MODULE", DEFAULT, "malformed modes declaration in channel database for channel %s", entry.name.c_str ( ));
					continue;
				}
				entry.modes = sep2.GetRemaining ( );
			}
		}
		/* return entry address */
		return &entry;
	}
};
/* class being a database writer, gets a database file name on construct */
class DatabaseWriter
{
	/* file stream */
	FILE *fd;
	std::string dbname, tmpname;
	ModeHandler *mh;
	/* public */
	public:
	/* constructor */
	DatabaseWriter (std::string filename, ModeHandler *handler)
	{
		fd = NULL;
		dbname = filename;
		tmpname = filename + ".tmp";
		mh = handler;
		/* ready, open temporary database */
		fd = fopen (tmpname.c_str ( ), "w");
		if (!fd)
		{
			ServerInstance->Logs->Log ("MODULE", DEFAULT, "cannot save to the channel database");
		}
	}
	/* destructor */
	~DatabaseWriter ( )
	{
		if (fd)
		{
			/* saving has been ended, close the database and flush buffers */
			fclose (fd);
			/* rename the database file */
			if (rename (tmpname.c_str ( ), dbname.c_str ( )) == -1)
			{
				ServerInstance->Logs->Log ("MODULE", DEFAULT, "can't rename the database file");
			}
		}
	}
	/* save the single channel */
	void next (Channel *chan)
	{
		if (!fd) return;
		/* first, construct the chaninfo line */
		std::string line;
		line.append ("chaninfo ").append (chan->name).append (" ").append (ConvToStr(chan->age))
			.append (" ").append (chan->IsModeSet(mh) ? chan->GetModeParameter (mh) : "-").append ("\n");
		if (fputs (line.c_str ( ), fd) == EOF)
		{
			ServerInstance->Logs->Log ("MODULE", DEFAULT, "unable to write the channel entry");
			fclose (fd);
			fd = NULL;
			return;
		}
		/* now, write the topic if present */
		if (!chan->topic.empty ( ))
		{
			line.clear ( );
			line.append ("topic ").append (ConvToStr (chan->topicset)).append (" ").append (chan->setby).append (" ").append (chan->topic).append ("\n");
			if (fputs (line.c_str ( ), fd) == EOF)
			{
				ServerInstance->Logs->Log ("MODULE", DEFAULT, "unable to write channel's topic declaration");
				fclose (fd);
				fd = NULL;
				return;
			}
		}
		/* get all channel modes */
		line.clear ( );
		irc::modestacker ms;
		chan->ChanModes (ms, MODELIST_FULL);
		line.append ("modes ").append (ms.popModeLine (FORMAT_PERSIST, INT_MAX, INT_MAX)).append ("\nend\n");
		if (fputs (line.c_str ( ), fd) == EOF)
		{
			ServerInstance->Logs->Log ("MODULE", DEFAULT, "can't write mode declaration");
			fclose (fd);
			fd = NULL;
			return;
		}
	}
};
/* class for handling +r mode */
class RegisterModeHandler : public ParamChannelModeHandler
{
 public:
	ChanExpiryExtItem last_activity;
	dynamic_reference<AccountProvider> account;
	bool verbose;
	int chanlimit;
	RegisterModeHandler(Module *me) : ParamChannelModeHandler(me, "registered", 'r'),
		last_activity(me), account("account")
	{
		/* set properties. */
		list = false;
		fixed_letter = false;
		oper = false;
		m_paramtype = TR_TEXT;
		levelrequired = OP_VALUE;
		verbose = true;
		chanlimit = 10;
	}

	void OnParameterMissing (User *user, User*, Channel *chan, std::string &param)
	{
		// put the user's own account name in the parameter, if missing
		if (account)
			param = account->GetAccountName(user);
	}
	/* make access checks */
	void AccessCheck(ModePermissionData& perm)
	{
		std::string acctname = account ? account->GetAccountName(perm.source) : "";

		if (perm.mc.adding)
		{
			if (perm.chan->IsModeSet(this))
			{
				perm.ErrorNumeric(ERR_CHANOPRIVSNEEDED, "%s :You must unregister the channel to change its registrants",
					perm.chan->name.c_str());
				perm.result = MOD_RES_DENY;
				return;
			}
			if (perm.source->HasPrivPermission("channels/set-registration", false))
			{
				perm.result = MOD_RES_ALLOW;
				return;
			}
			/* new functionality, you can't register any channel if you don't have the oper privilege and chanlimit == 0 */
			if (chanlimit == 0)
			{
				perm.ErrorNumeric (ERR_NOPRIVILEGES, ":Permission denied - only IRC operators may register channels");
				perm.result = MOD_RES_DENY;
				return;
			}
			/* calculate how many channels the user has registered himself */
			int chans = 0;
			for (chan_hash::const_iterator it = ServerInstance->chanlist->begin ( ); it != ServerInstance->chanlist->end ( ); it++)
			{
				if (it->second->IsModeSet (this))
				{
					irc::commasepstream registrantnames (it->second->GetModeParameter (this));
					std::string token;
					registrantnames.GetToken (token);
					if (token == acctname) chans++;
				}
			}
			/* check for limit */
			if (chans >= chanlimit)
			{
				perm.ErrorNumeric(ERR_CHANOPRIVSNEEDED, "%s :You can't register more than %i channels under one account", perm.chan->name.c_str(), chans);
				perm.result = MOD_RES_DENY;
				return;
			}
			/* otherwise, you can only set it to your own account name */
			irc::commasepstream registrantnames(perm.mc.value);
			std::string registrantname;
			/* if the account name was not given, is empty or is not equal to the given parameter, deny */
			if (acctname.empty() || !registrantnames.GetToken(registrantname) || acctname != registrantname)
			{
				perm.ErrorNumeric(ERR_CHANOPRIVSNEEDED, "%s :You must be logged in to the first account in the registrant list",
					perm.chan->name.c_str());
				perm.result = MOD_RES_DENY;
			}
		}
		else
		{
			/* removing a mode: must be a registrant */
			if (acctname.empty())
			{
				// not logged in: different error message
				perm.ErrorNumeric(ERR_CHANOPRIVSNEEDED, "%s :You must be logged in to an account to unregister a channel",
					perm.chan->name.c_str());
				perm.result = MOD_RES_DENY;
				return;
			}
			irc::commasepstream registrantnames(perm.chan->GetModeParameter(this));
			std::string registrantname;
			while (registrantnames.GetToken(registrantname))
			{
				if (acctname == registrantname)
				{
					// go ahead and skip the rest of the checks
					perm.result = MOD_RES_ALLOW;
					return;
				}
			}
			// no matching account name
			perm.ErrorNumeric(ERR_CHANOPRIVSNEEDED, "%s :Only a registrant of a channel may unregister it",
				perm.chan->name.c_str());
			perm.result = MOD_RES_DENY;
		}
	}

	ModeAction OnModeChange (User *source, User*, Channel *chan, std::string &param, bool adding)
	{
		if (adding)
		{
			std::string now = chan->GetModeParameter(this);
			if (param == now)
				return MODEACTION_DENY;
			if (!now.empty())
			{
				ServerInstance->SNO->WriteToSnoMask(IS_LOCAL(source) ? 'r' : 'R', "%s changed registration of %s from %s to %s",
					source->GetFullHost().c_str(), chan->name.c_str(), now.c_str(), param.c_str());
				if (verbose)
					chan->WriteChannel(ServerInstance->FakeClient, "NOTICE %s :This channel has been reregistered (%s -> %s)",
						chan->name.c_str(), now.c_str(), param.c_str());
			}
			/* servers are expected to notice their reasons themselves */
			else if (!IS_SERVER(source))
			{
				/* first, send a message to all ircops with snomask +r set */
				ServerInstance->SNO->WriteToSnoMask (IS_LOCAL (source) ? 'r' : 'R', "%s registered channel %s to account %s", source->GetFullHost ( ).c_str ( ), chan->name.c_str ( ), param.c_str ( ));
				/* now, send similar to channel */
				if (verbose)
					chan->WriteChannel (ServerInstance->FakeClient, "NOTICE %s :This channel has been registered",
					chan->name.c_str ( ));
			}
			chan->SetModeParam (this, param);
		}
		else
		{
			/* servers are expected to notice their reasons themselves */
			if (!IS_SERVER(source))
			{
				/* it is set, so first send a server notice to all ircops using +r snomask that this channel has been unregistered */
				ServerInstance->SNO->WriteToSnoMask (IS_LOCAL (source) ? 'r' : 'R', "channel %s unregistered by %s", chan->name.c_str ( ), source->GetFullHost ( ).c_str ( ));
				/* then send this important message to the channel as the notice */
				if (verbose)
					chan->WriteChannel (ServerInstance->FakeClient, "NOTICE %s :This channel has been unregistered",
					chan->name.c_str ( ));
			}
			chan->SetModeParam(this, "");
			last_activity.unset(chan);
			/* now, if usercount is 0, delete the channel */
			if (!chan->GetUserCounter())
				chan->DelUser(ServerInstance->FakeClient);
		}
		return MODEACTION_ALLOW;
	}

	void set_prefixrequired (ModeHandler *mh)
	{
		levelrequired = mh->GetPrefixRank();
	}
};

class ChannelRegistrationModule : public Module
{
 private:
	/* some config variables */
	std::string chandb;
	bool dirty;
	time_t expiretime;
	/* modehandler handling registration mode */
	RegisterModeHandler mh;
	/* check if the channel given as a parameter expired */
	bool Expired (Channel *chan)
	{
		/* if mode +r is not set, it didn't */
		if (!chan->IsModeSet (&mh)) return false;
		/* if +P was set, it didn't too */
		if (chan->IsModeSet ("permanent")) return false;
		/* channel is the user-owned channel without noexpire set, so it expires, but we must check if it expired now */
		if (ServerInstance->Time ( ) - expiretime >= mh.last_activity.get (chan)) return true;
		return false;
	}
	/* write the channel database */
	void WriteDatabase ( )
	{
		/* step1: create the database writer that opens the temporary database file for writing */
		DatabaseWriter db (chandb, &mh);
		/* ready, start a loop */
		for (chan_hash::const_iterator i = ServerInstance->chanlist->begin ( ); i != ServerInstance->chanlist->end ( ); i++)
		{
			/* write the channel if it has mode set */
			if ((i->second->IsModeSet (&mh)) || i->second->IsModeSet ("permanent")) db.next (i->second);
		}
		/* completed all iterations, function now goes down, that will destruct the database writer */
		/* while destruction, it will close the temporary file and rename it to a real database file, completing write process */
	}
	/* read the channel database */
	void ReadDatabase ( )
	{
		/* create the reader object and open the database */
		DatabaseReader db (chandb);
		/* start the database read loop */
		EntryDescriptor *entry;
		while ((entry = db.next ( )))
		{
			/* we get a database entry */
			/* so if channel name doesn't start with #, give an error and continue */
			if (entry->name[0] != '#')
			{
				ServerInstance->Logs->Log ("MODULE", DEFAULT, "invalid channel name in channel database");
				continue;
			}
			/* entry is valid */
			/* try to find the channel */
			Channel *chan = ServerInstance->FindChan (entry->name);
			/* now, things that will be done depends on if channel was found or not */
			if (chan)
			{
				/* if it was found, then channel timestamp becomes not important, only things needing to be set is the registrant status, do it */
				/* if registrant is -, set +P instead */
				if (entry->registrant == "-")
				{
					irc::modestacker ms;
					irc::modechange mc("permanent");
					if (mc.mode.GetID())
						ms.push(mc);
					ServerInstance->SendMode(ServerInstance->FakeClient, chan, ms, false);
				}
				/* if not, set +r */
				else
				{
					/* create the mode stacker */
					irc::modestacker ms;
					/* we need to push the mode change */
					ms.push (irc::modechange ("registered", entry->registrant));
					/* make the server process and apply the mode change */
					ServerInstance->Modes->Process (ServerInstance->FakeClient, chan, ms);
					/* we don't do it below because channel doesn't exist then */
					/* but in this situation, channel exists and there are users on it, they must know that mode has been changed */
					/* send that info to them */
					ServerInstance->Modes->Send (ServerInstance->FakeClient, chan, ms);
				}
			} else
			{
				/* channel does not exist, allocate it, it will be constructed and added to the network as an empty channel */
				chan = new Channel (entry->name, atol (entry->ts.c_str ( )));
				/* empty modeless channel added and allocated */
				/* so, channel exists in the network, then if topic is not empty, set data */
				if (!entry->topic.empty ( ))
				{
					chan->topic = entry->topic;
					chan->topicset = atol (entry->topicset.c_str ( ));
					chan->setby = entry->topicsetby;
				}
				/* if modestring is not empty, then set all modes in it */
				if (!entry->modes.empty ( ))
				{
					/* create sepstream */
					irc::spacesepstream sep(entry->modes);
					/* create modestacker for stacking all mode changes */
					irc::modestacker ms;
					/* spacesepstream is used to iterate through all modes that were saved for a channel */
					/* modestacker ms is used to stack them */
					/* iterate through the mode list */
					while (!sep.StreamEnd ( ))
					{
						/* get the mode to be applied */
						std::string token, name, value;
						sep.GetToken (token);
						/* the mode looks like name=value unless it doesn't have any value then it's just name */
						/* find the position of = sign */
						size_t namepos = token.find ('=');
						/* if we didn't find anything, set name to the token because mode is... valueless */
						if (namepos == std::string::npos) name = token;
						/* if it found that = sign, we have both name and value */
						else
						{
							/* it found it, name is string before the character, value is the string after it */
							name = token.substr (0, namepos);
							value = token.substr (namepos + 1);
						}
						/* mode name and value found, we can now add it to the modestacker */
						/* hmm, or we can't, reason is that letters are separate in user and channel modes, but mode names are not, so what if this thing we're setting is
						an user mode? */
						/* to check that, we must find the mode */
						ModeHandler *mc = ServerInstance->Modes->FindMode (name);
						/* those actions will be taken only if mode was found and if it's the channel mode */
						if (mc && mc->GetModeType ( ) == MODETYPE_CHANNEL)
						{
							/* mode was found and is not an user mode but a channel mode, push it to the modestacker, we use id instead of name for quicker push because we
							have the mode handler now */
							ms.push (irc::modechange (mc->id, value));
						}
					}
					/* okay, all modes were pushed, modestacker can now produce the mode line */
					/* so, process all mode changes and apply them on a channel */
					ServerInstance->Modes->Process (ServerInstance->FakeClient, chan, ms);
				}
				/* if some error was found like no modes line, set registrant or permanent */
				if ((!chan->IsModeSet (&mh)) || (!chan->IsModeSet ("permanent")))
				{
					irc::modestacker ms2;
					if (entry->registrant != "-")
						ms2.push (irc::modechange ("registered", entry->registrant));
					else {
						irc::modechange mc("permanent");
						if (mc.mode.GetID())
							ms2.push(mc);
					}
					ServerInstance->Modes->Process (ServerInstance->FakeClient, chan, ms2);
				}
				/* channel is empty, and thus, should be checked for expiry, but we can't do it while we have no last activity timestamp, so set it */
				if (chan->IsModeSet (&mh))
					mh.last_activity.set (chan, ServerInstance->Time ( ));
			}
		}
	}
 public:
	/* module constructor, for initializing stuff */
	ChannelRegistrationModule ( ) : mh (this)
	{
	}
	/* get module version and flags. */
	Version GetVersion ( )
	{
		return Version("Provides channel mode +r for channel registration", VF_VENDOR);
	}
	void init ( )
	{
		/* enable the snomask for channel registration */
		ServerInstance->SNO->EnableSnomask ('r', "CHANREGISTER");
		/* attach events */
		Implementation eventlist[] = {I_OnCheckJoin, I_OnPermissionCheck, I_OnChannelPreDelete, I_OnBackgroundTimer, I_OnMode,
		I_OnPostTopicChange, I_OnRawMode, I_OnUserQuit, I_OnUserPart, I_OnUserKick, I_OnGarbageCollect};
		ServerInstance->Modules->Attach (eventlist, this, 11);
		/* add a new service that is a new channel mode handler for handling channel registration mode */
		ServerInstance->Modules->AddService (mh);
		/* register a new extension item with the name last_activity */
		ServerInstance->Modules->AddService(mh.last_activity);
		/* rehash procedures finished, read the database if we have one */
		if (!chandb.empty())
			ReadDatabase ( );
		/* after database read, it's possible some channels must be updated, do it now */
		dirty = true;
	}
	/* rehash event */
	void ReadConfig(ConfigReadStatus&)
	{
		/* try to download the tag from the config system */
		ConfigTag *chregistertag = ServerInstance->Config->ConfValue ("chanregister");
		/* get the prefix mode */
		std::string prefixmode = chregistertag->getString ("prefix", "op");
		/* get the channel database */
		chandb = chregistertag->getString ("chandb", "");
		/* get the expire time and convert it to time_t */
		expiretime = ServerInstance->Duration (chregistertag->getString ("expiretime", "21d"));
		/* set verbose directly in a modehandler */
		mh.verbose = chregistertag->getBool ("verbose", true);
		/* set channel limit in a modehandler too */
		mh.chanlimit = chregistertag->getInt ("limit", 10);
		/* check if prefix exists, if not, throw an exception */
		ModeHandler *prefixmodehandler = ServerInstance->Modes->FindMode (prefixmode);
		if (!prefixmodehandler)
			throw CoreException ("Module providing the configured prefix is not loaded");
		mh.set_prefixrequired (prefixmodehandler);
	}
	/* OnCheckJoin - this is an event for checking permissions of some user to join some channel, it is used to allow joining by registrants even when
banned */
	void OnCheckJoin (ChannelPermissionData &joindata)
	{
		/* if channel is null, it's not something that is done on channels, or it is but channel is being created, so no registrant in it */
		if (!joindata.chan)
			return;
		/* return if mode is not set and channel is unregistered */
		if (!joindata.chan->IsModeSet (&mh))
			return;
		/* get user's account name */
		std::string acctname = mh.account ? mh.account->GetAccountName(joindata.source) : "";
		/* if account is not found or empty, we can be really sure that we really aren't registrant of any channel */
		if (acctname.empty())
			return;
		/* it is set and we have parameter, get it */
		irc::commasepstream registrantnames(joindata.chan->GetModeParameter(&mh));
		std::string registrantname;
		while (registrantnames.GetToken(registrantname))
		{
			if (acctname == registrantname)
			{
				/* if registrantname and account name are the same, override */
				joindata.result = MOD_RES_ALLOW;
				return;
			}
		}
	}
	/* check permissions */
	void OnPermissionCheck (PermissionData &perm)
	{
		/* if channel is null, proceed normally */
		if (!perm.chan)
			return;
		/* if not, but name of permission is join, proceed normally because it was checked */
		if (perm.name == "join")
			return;
		/* if +r mode is changed, return */
		if (perm.name == "mode/registered")
			return;
		/* if anything is ok, but mode +r is unset, return and check perms normally */
		if (!perm.chan->IsModeSet (&mh))
			return;
		/* if set, get the registrant account name */
		/* get account name of the current user */
		std::string acctname = mh.account ? mh.account->GetAccountName(perm.source) : "";
		/* if user is not logged in then return */
		if (acctname.empty())
			return;
		irc::commasepstream registrantnames(perm.chan->GetModeParameter(&mh));
		std::string registrantname;
		while (registrantnames.GetToken(registrantname))
		{
			if (acctname == registrantname)
			{
				/* if ok, then set result to allow if registrant name matches account name */
				perm.result = MOD_RES_ALLOW;
				return;
			}
		}
	}
	/* called before channel is being deleted */
	ModResult OnChannelPreDelete (Channel *chan)
	{
		/* return 1 to prevent channel deletion if channel is registered */
		if (chan->IsModeSet(&mh))
			return MOD_RES_DENY;
		/* in other case, return 0, to allow channel deletion */
		return MOD_RES_PASSTHRU;
	}
	/* called on background timer to write all channels to disk if they were changed */
	void OnBackgroundTimer (time_t cur)
	{
		/* if not dirty then don't do anything */
		if (!dirty)
			return;
		/* dirty, one of registered channels was changed, save it */
		if (!chandb.empty())
			WriteDatabase ( );
		/* clear dirty to prevent next savings */
		dirty = false;
	}
	/* after the topic has been changed, call this to check if channel was registered */
	void OnPostTopicChange (User *user, Channel *chan, const std::string &topic)
	{
		/* if the channel is not registered, don't do anything, but if channel has been registered, this must be saved, so mark database as to be saved */
		if ((chan->IsModeSet (&mh)) || (chan->IsModeSet ("permanent")))
			dirty = true;
	}
	/* this event is called after each modechange */
	void OnMode (User *user, Extensible *target, const irc::modestacker &modes)
	{
		Channel *chan = IS_CHANNEL(target);
		if (!chan)
			return;
		/* if it's a registered channel, then the database was changed and must be saved */
		if ((chan->IsModeSet (&mh)) || (chan->IsModeSet ("permanent")))
			dirty = true;
	}
	/* when someone unsets +r, OnMode event won't mark the database as requiring saving, but it requires to be saved, and because of this, this event
	handler is needed */
	/* it catches all mode changes, and sets database as dirty if register mode is being removed */
	ModResult OnRawMode (User *user, Channel *chan, irc::modechange &mc)
	{
		/* if mode is being removed and this is our mode then mark as dirty */
		if (!mc.adding)
		{
			ModeHandler *mh2 = ServerInstance->Modes->FindMode ("permanent");
			if (mc.mode == mh.id)
				dirty = true;
			if (mh2 && mc.mode == mh2->id)
				dirty = true;
		}
		/* this is the only thing this module does, so pass through */
		return MOD_RES_PASSTHRU;
	}
	/* this is called when some user parts a channel and is used to record the time user parted as the last activity time */
	/* this is done only if channel is registered, and is used only when it's empty */
	void OnUserPart (Membership *memb, std::string &msg, CUList &except_list)
	{
		/* we have some membership, let's set this last part time now */
		if (memb->chan->IsModeSet (&mh))
			mh.last_activity.set (memb->chan, ServerInstance->Time ( ));
	}
	/* called when the user is being kicked, it's also used for setting last activity time */
	void OnUserKick (User *source, Membership *memb, const std::string &reason, CUList &except_list)
	{
		/* the same */
		if (memb->chan->IsModeSet (&mh))
			mh.last_activity.set (memb->chan, ServerInstance->Time ( ));
	}
	/* if user quits, set last activity time for each channel he was in that are registered */
	void OnUserQuit (User *user, const std::string &msg, const std::string &opermsg)
	{
		/* iterate through a channel list */
		for (UCListIter it = user->chans.begin ( ); it != user->chans.end ( ); it++)
		{
			/* for each membership, check if channel is registered, if it is, set last activity time for it */
			if (it->chan->IsModeSet (&mh))
				mh.last_activity.set (it->chan, ServerInstance->Time ( ));
		}
	}
	/* called once a hour to expire expired channels */
	void OnGarbageCollect ( )
	{
		/* iterate through all channels */
		for (chan_hash::const_iterator it = ServerInstance->chanlist->begin ( ); it != ServerInstance->chanlist->end ( ); it++)
		{
			/* check if the channel was expired and is empty at the same time */
			if (it->second->GetUserCounter ( ) == 0 && Expired (it->second))
			{
				/* send a notice */
				ServerInstance->SNO->WriteGlobalSno ('r', "Channel %s was expired", it->second->name.c_str ( ));
				/* send mode -r */
				irc::modestacker ms;
				ms.push (irc::modechange (mh.id, "", false));
				ServerInstance->SendMode (ServerInstance->FakeClient, it->second, ms, true);
			}
		}
	}
	void Prioritize()
	{
		// database reading may depend on channel modes being loaded
		ServerInstance->Modules->SetPriority(this, I_ModuleInit, PRIORITY_LAST);
	}
};
/* register the module */
MODULE_INIT(ChannelRegistrationModule)