/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
 *   Copyright (C) 2006-2008 Robin Burchell <robin+git@viroteck.net>
 *   Copyright (C) 2006, 2008 Oliver Lupton <oliverlupton@gmail.com>
 *   Copyright (C) 2008 Pippijn van Steenhoven <pip88nl@gmail.com>
 *   Copyright (C) 2003-2008 Craig Edwards <craigedwards@brainbox.cc>
 *   Copyright (C) 2008 Thomas Stagner <aquanight@inspircd.org>
 *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
 *
 * This file is part of InspIRCd.  InspIRCd 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, version 2.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */


#include "inspircd.h"
#include "listmode.h"
#include <cstdarg>
#include "mode.h"

namespace
{
	ChanModeReference ban(NULL, "ban");
	ChanModeReference inviteonlymode(NULL, "inviteonly");
	ChanModeReference keymode(NULL, "key");
	ChanModeReference limitmode(NULL, "limit");
	ChanModeReference secretmode(NULL, "secret");
	ChanModeReference privatemode(NULL, "private");
	UserModeReference invisiblemode(NULL, "invisible");
}

Channel::Channel(const std::string &cname, time_t ts)
	: name(cname), age(ts), topicset(0)
{
	if (!ServerInstance->chanlist.insert(std::make_pair(cname, this)).second)
		throw CoreException("Cannot create duplicate channel " + cname);
}

void Channel::SetMode(ModeHandler* mh, bool on)
{
	modes[mh->GetId()] = on;
}

void Channel::SetTopic(User* u, const std::string& ntopic)
{
	this->topic.assign(ntopic, 0, ServerInstance->Config->Limits.MaxTopic);
	this->setby.assign(ServerInstance->Config->FullHostInTopic ? u->GetFullHost() : u->nick, 0, 128);
	this->WriteChannel(u, "TOPIC %s :%s", this->name.c_str(), this->topic.c_str());
	this->topicset = ServerInstance->Time();

	FOREACH_MOD(OnPostTopicChange, (u, this, this->topic));
}

Membership* Channel::AddUser(User* user)
{
	Membership*& memb = userlist[user];
	if (memb)
		return NULL;

	memb = new Membership(user, this);
	return memb;
}

void Channel::DelUser(User* user)
{
	UserMembIter it = userlist.find(user);
	if (it != userlist.end())
		DelUser(it);
}

void Channel::CheckDestroy()
{
	if (!userlist.empty())
		return;

	ModResult res;
	FIRST_MOD_RESULT(OnChannelPreDelete, res, (this));
	if (res == MOD_RES_DENY)
		return;

	chan_hash::iterator iter = ServerInstance->chanlist.find(this->name);
	/* kill the record */
	if (iter != ServerInstance->chanlist.end())
	{
		FOREACH_MOD(OnChannelDelete, (this));
		ServerInstance->chanlist.erase(iter);
	}

	ClearInvites();
	ServerInstance->GlobalCulls.AddItem(this);
}

void Channel::DelUser(const UserMembIter& membiter)
{
	Membership* memb = membiter->second;
	memb->cull();
	delete memb;
	userlist.erase(membiter);

	// If this channel became empty then it should be removed
	CheckDestroy();
}

Membership* Channel::GetUser(User* user)
{
	UserMembIter i = userlist.find(user);
	if (i == userlist.end())
		return NULL;
	return i->second;
}

void Channel::SetDefaultModes()
{
	ServerInstance->Logs->Log("CHANNELS", LOG_DEBUG, "SetDefaultModes %s",
		ServerInstance->Config->DefaultModes.c_str());
	irc::spacesepstream list(ServerInstance->Config->DefaultModes);
	std::string modeseq;
	std::string parameter;

	list.GetToken(modeseq);

	for (std::string::iterator n = modeseq.begin(); n != modeseq.end(); ++n)
	{
		ModeHandler* mode = ServerInstance->Modes->FindMode(*n, MODETYPE_CHANNEL);
		if (mode)
		{
			if (mode->IsPrefixMode())
				continue;

			if (mode->GetNumParams(true))
				list.GetToken(parameter);
			else
				parameter.clear();

			mode->OnModeChange(ServerInstance->FakeClient, ServerInstance->FakeClient, this, parameter, true);
		}
	}
}

/*
 * add a channel to a user, creating the record for it if needed and linking
 * it to the user record
 */
Channel* Channel::JoinUser(LocalUser* user, std::string cname, bool override, const std::string& key)
{
	if (user->registered != REG_ALL)
	{
		ServerInstance->Logs->Log("CHANNELS", LOG_DEBUG, "Attempted to join unregistered user " + user->uuid + " to channel " + cname);
		return NULL;
	}

	/*
	 * We don't restrict the number of channels that remote users or users that are override-joining may be in.
	 * We restrict local users to MaxChans channels.
	 * We restrict local operators to OperMaxChans channels.
	 * This is a lot more logical than how it was formerly. -- w00t
	 */
	if (!override)
	{
		if (user->HasPrivPermission("channels/high-join-limit"))
		{
			if (user->chans.size() >= ServerInstance->Config->OperMaxChans)
			{
				user->WriteNumeric(ERR_TOOMANYCHANNELS, "%s :You are on too many channels", cname.c_str());
				return NULL;
			}
		}
		else
		{
			unsigned int maxchans = user->GetClass()->maxchans;
			if (!maxchans)
				maxchans = ServerInstance->Config->MaxChans;
			if (user->chans.size() >= maxchans)
			{
				user->WriteNumeric(ERR_TOOMANYCHANNELS, "%s :You are on too many channels", cname.c_str());
				return NULL;
			}
		}
	}

	// Crop channel name if it's too long
	if (cname.length() > ServerInstance->Config->Limits.ChanMax)
		cname.resize(ServerInstance->Config->Limits.ChanMax);

	Channel* chan = ServerInstance->FindChan(cname);
	bool created_by_local = (chan == NULL); // Flag that will be passed to modules in the OnUserJoin() hook later
	std::string privs; // Prefix mode(letter)s to give to the joining user

	if (!chan)
	{
		privs = ServerInstance->Config->DefaultModes.substr(0, ServerInstance->Config->DefaultModes.find(' '));

		if (override == false)
		{
			// Ask the modules whether they're ok with the join, pass NULL as Channel* as the channel is yet to be created
			ModResult MOD_RESULT;
			FIRST_MOD_RESULT(OnUserPreJoin, MOD_RESULT, (user, NULL, cname, privs, key));
			if (MOD_RESULT == MOD_RES_DENY)
				return NULL; // A module wasn't happy with the join, abort
		}

		chan = new Channel(cname, ServerInstance->Time());
		// Set the default modes on the channel (<options:defaultmodes>)
		chan->SetDefaultModes();
	}
	else
	{
		/* Already on the channel */
		if (chan->HasUser(user))
			return NULL;

		if (override == false)
		{
			ModResult MOD_RESULT;
			FIRST_MOD_RESULT(OnUserPreJoin, MOD_RESULT, (user, chan, cname, privs, key));

			// A module explicitly denied the join and (hopefully) generated a message
			// describing the situation, so we may stop here without sending anything
			if (MOD_RESULT == MOD_RES_DENY)
				return NULL;

			// If no module returned MOD_RES_DENY or MOD_RES_ALLOW (which is the case
			// most of the time) then proceed to check channel modes +k, +i, +l and bans,
			// in this order.
			// If a module explicitly allowed the join (by returning MOD_RES_ALLOW),
			// then this entire section is skipped
			if (MOD_RESULT == MOD_RES_PASSTHRU)
			{
				std::string ckey = chan->GetModeParameter(keymode);
				bool invited = user->IsInvited(chan);
				bool can_bypass = ServerInstance->Config->InvBypassModes && invited;

				if (!ckey.empty())
				{
					FIRST_MOD_RESULT(OnCheckKey, MOD_RESULT, (user, chan, key));
					if (!MOD_RESULT.check((ckey == key) || can_bypass))
					{
						// If no key provided, or key is not the right one, and can't bypass +k (not invited or option not enabled)
						user->WriteNumeric(ERR_BADCHANNELKEY, "%s :Cannot join channel (Incorrect channel key)", chan->name.c_str());
						return NULL;
					}
				}

				if (chan->IsModeSet(inviteonlymode))
				{
					FIRST_MOD_RESULT(OnCheckInvite, MOD_RESULT, (user, chan));
					if (!MOD_RESULT.check(invited))
					{
						user->WriteNumeric(ERR_INVITEONLYCHAN, "%s :Cannot join channel (Invite only)", chan->name.c_str());
						return NULL;
					}
				}

				std::string limit = chan->GetModeParameter(limitmode);
				if (!limit.empty())
				{
					FIRST_MOD_RESULT(OnCheckLimit, MOD_RESULT, (user, chan));
					if (!MOD_RESULT.check((chan->GetUserCounter() < atol(limit.c_str()) || can_bypass)))
					{
						user->WriteNumeric(ERR_CHANNELISFULL, "%s :Cannot join channel (Channel is full)", chan->name.c_str());
						return NULL;
					}
				}

				if (chan->IsBanned(user) && !can_bypass)
				{
					user->WriteNumeric(ERR_BANNEDFROMCHAN, "%s :Cannot join channel (You're banned)", chan->name.c_str());
					return NULL;
				}

				/*
				 * If the user has invites for this channel, remove them now
				 * after a successful join so they don't build up.
				 */
				if (invited)
				{
					user->RemoveInvite(chan);
				}
			}
		}
	}

	// We figured that this join is allowed and also created the
	// channel if it didn't exist before, now do the actual join
	chan->ForceJoin(user, &privs, false, created_by_local);
	return chan;
}

void Channel::ForceJoin(User* user, const std::string* privs, bool bursting, bool created_by_local)
{
	if (IS_SERVER(user))
	{
		ServerInstance->Logs->Log("CHANNELS", LOG_DEBUG, "Attempted to join server user " + user->uuid + " to channel " + this->name);
		return;
	}

	Membership* memb = this->AddUser(user);
	if (!memb)
		return; // Already on the channel

	user->chans.push_front(memb);

	if (privs)
	{
		// If the user was granted prefix modes (in the OnUserPreJoin hook, or he's a
		// remote user and his own server set the modes), then set them internally now
		for (std::string::const_iterator i = privs->begin(); i != privs->end(); ++i)
		{
			PrefixMode* mh = ServerInstance->Modes->FindPrefixMode(*i);
			if (mh)
			{
				std::string nick = user->nick;
				// Set the mode on the user
				mh->OnModeChange(ServerInstance->FakeClient, NULL, this, nick, true);
			}
		}
	}

	// Tell modules about this join, they have the chance now to populate except_list with users we won't send the JOIN (and possibly MODE) to
	CUList except_list;
	FOREACH_MOD(OnUserJoin, (memb, bursting, created_by_local, except_list));

	this->WriteAllExcept(user, false, 0, except_list, "JOIN :%s", this->name.c_str());

	/* Theyre not the first ones in here, make sure everyone else sees the modes we gave the user */
	if ((GetUserCounter() > 1) && (!memb->modes.empty()))
	{
		std::string ms = memb->modes;
		for(unsigned int i=0; i < memb->modes.length(); i++)
			ms.append(" ").append(user->nick);

		except_list.insert(user);
		this->WriteAllExcept(user, !ServerInstance->Config->CycleHostsFromUser, 0, except_list, "MODE %s +%s", this->name.c_str(), ms.c_str());
	}

	if (IS_LOCAL(user))
	{
		if (this->topicset)
		{
			user->WriteNumeric(RPL_TOPIC, "%s :%s", this->name.c_str(), this->topic.c_str());
			user->WriteNumeric(RPL_TOPICTIME, "%s %s %lu", this->name.c_str(), this->setby.c_str(), (unsigned long)this->topicset);
		}
		this->UserList(user);
	}

	FOREACH_MOD(OnPostJoin, (memb));
}

bool Channel::IsBanned(User* user)
{
	ModResult result;
	FIRST_MOD_RESULT(OnCheckChannelBan, result, (user, this));

	if (result != MOD_RES_PASSTHRU)
		return (result == MOD_RES_DENY);

	ListModeBase* banlm = static_cast<ListModeBase*>(*ban);
	const ListModeBase::ModeList* bans = banlm->GetList(this);
	if (bans)
	{
		for (ListModeBase::ModeList::const_iterator it = bans->begin(); it != bans->end(); it++)
		{
			if (CheckBan(user, it->mask))
				return true;
		}
	}
	return false;
}

bool Channel::CheckBan(User* user, const std::string& mask)
{
	ModResult result;
	FIRST_MOD_RESULT(OnCheckBan, result, (user, this, mask));
	if (result != MOD_RES_PASSTHRU)
		return (result == MOD_RES_DENY);

	// extbans were handled above, if this is one it obviously didn't match
	if ((mask.length() <= 2) || (mask[1] == ':'))
		return false;

	std::string::size_type at = mask.find('@');
	if (at == std::string::npos)
		return false;

	const std::string nickIdent = user->nick + "!" + user->ident;
	std::string prefix = mask.substr(0, at);
	if (InspIRCd::Match(nickIdent, prefix, NULL))
	{
		std::string suffix = mask.substr(at + 1);
		if (InspIRCd::Match(user->host, suffix, NULL) ||
			InspIRCd::Match(user->dhost, suffix, NULL) ||
			InspIRCd::MatchCIDR(user->GetIPString(), suffix, NULL))
			return true;
	}
	return false;
}

ModResult Channel::GetExtBanStatus(User *user, char type)
{
	ModResult rv;
	FIRST_MOD_RESULT(OnExtBanCheck, rv, (user, this, type));
	if (rv != MOD_RES_PASSTHRU)
		return rv;

	ListModeBase* banlm = static_cast<ListModeBase*>(*ban);
	const ListModeBase::ModeList* bans = banlm->GetList(this);
	if (bans)
	{
		for (ListModeBase::ModeList::const_iterator it = bans->begin(); it != bans->end(); ++it)
		{
			if (CheckBan(user, it->mask))
				return MOD_RES_DENY;
		}
	}
	return MOD_RES_PASSTHRU;
}

/* Channel::PartUser
 * Remove a channel from a users record, remove the reference to the Membership object
 * from the channel and destroy it.
 */
void Channel::PartUser(User *user, std::string &reason)
{
	UserMembIter membiter = userlist.find(user);

	if (membiter != userlist.end())
	{
		Membership* memb = membiter->second;
		CUList except_list;
		FOREACH_MOD(OnUserPart, (memb, reason, except_list));

		WriteAllExcept(user, false, 0, except_list, "PART %s%s%s", this->name.c_str(), reason.empty() ? "" : " :", reason.c_str());

		// Remove this channel from the user's chanlist
		user->chans.erase(memb);
		// Remove the Membership from this channel's userlist and destroy it
		this->DelUser(membiter);
	}
}

void Channel::KickUser(User* src, User* victim, const std::string& reason, Membership* srcmemb)
{
	UserMembIter victimiter = userlist.find(victim);
	Membership* memb = ((victimiter != userlist.end()) ? victimiter->second : NULL);

	if (!memb)
	{
		src->WriteNumeric(ERR_USERNOTINCHANNEL, "%s %s :They are not on that channel", victim->nick.c_str(), this->name.c_str());
		return;
	}

	// Do the following checks only if the KICK is done by a local user;
	// each server enforces its own rules.
	if (IS_LOCAL(src))
	{
		// Modules are allowed to explicitly allow or deny kicks done by local users
		ModResult res;
		FIRST_MOD_RESULT(OnUserPreKick, res, (src,memb,reason));
		if (res == MOD_RES_DENY)
			return;

		if (res == MOD_RES_PASSTHRU)
		{
			if (!srcmemb)
				srcmemb = GetUser(src);
			unsigned int them = srcmemb ? srcmemb->getRank() : 0;
			unsigned int req = HALFOP_VALUE;
			for (std::string::size_type i = 0; i < memb->modes.length(); i++)
			{
				ModeHandler* mh = ServerInstance->Modes->FindMode(memb->modes[i], MODETYPE_CHANNEL);
				if (mh && mh->GetLevelRequired() > req)
					req = mh->GetLevelRequired();
			}

			if (them < req)
			{
				src->WriteNumeric(ERR_CHANOPRIVSNEEDED, "%s :You must be a channel %soperator",
					this->name.c_str(), req > HALFOP_VALUE ? "" : "half-");
				return;
			}
		}
	}

	CUList except_list;
	FOREACH_MOD(OnUserKick, (src, memb, reason, except_list));

	WriteAllExcept(src, false, 0, except_list, "KICK %s %s :%s", name.c_str(), victim->nick.c_str(), reason.c_str());

	victim->chans.erase(memb);
	this->DelUser(victimiter);
}

void Channel::WriteChannel(User* user, const char* text, ...)
{
	std::string textbuffer;
	VAFORMAT(textbuffer, text, text);
	this->WriteChannel(user, textbuffer);
}

void Channel::WriteChannel(User* user, const std::string &text)
{
	const std::string message = ":" + user->GetFullHost() + " " + text;

	for (UserMembIter i = userlist.begin(); i != userlist.end(); i++)
	{
		if (IS_LOCAL(i->first))
			i->first->Write(message);
	}
}

void Channel::WriteChannelWithServ(const std::string& ServName, const char* text, ...)
{
	std::string textbuffer;
	VAFORMAT(textbuffer, text, text);
	this->WriteChannelWithServ(ServName, textbuffer);
}

void Channel::WriteChannelWithServ(const std::string& ServName, const std::string &text)
{
	const std::string message = ":" + (ServName.empty() ? ServerInstance->Config->ServerName : ServName) + " " + text;

	for (UserMembIter i = userlist.begin(); i != userlist.end(); i++)
	{
		if (IS_LOCAL(i->first))
			i->first->Write(message);
	}
}

/* write formatted text from a source user to all users on a channel except
 * for the sender (for privmsg etc) */
void Channel::WriteAllExceptSender(User* user, bool serversource, char status, const char* text, ...)
{
	std::string textbuffer;
	VAFORMAT(textbuffer, text, text);
	this->WriteAllExceptSender(user, serversource, status, textbuffer);
}

void Channel::WriteAllExcept(User* user, bool serversource, char status, CUList &except_list, const char* text, ...)
{
	std::string textbuffer;
	VAFORMAT(textbuffer, text, text);
	textbuffer = ":" + (serversource ? ServerInstance->Config->ServerName : user->GetFullHost()) + " " + textbuffer;
	this->RawWriteAllExcept(user, serversource, status, except_list, textbuffer);
}

void Channel::WriteAllExcept(User* user, bool serversource, char status, CUList &except_list, const std::string &text)
{
	const std::string message = ":" + (serversource ? ServerInstance->Config->ServerName : user->GetFullHost()) + " " + text;
	this->RawWriteAllExcept(user, serversource, status, except_list, message);
}

void Channel::RawWriteAllExcept(User* user, bool serversource, char status, CUList &except_list, const std::string &out)
{
	unsigned int minrank = 0;
	if (status)
	{
		PrefixMode* mh = ServerInstance->Modes->FindPrefix(status);
		if (mh)
			minrank = mh->GetPrefixRank();
	}
	for (UserMembIter i = userlist.begin(); i != userlist.end(); i++)
	{
		if (IS_LOCAL(i->first) && (except_list.find(i->first) == except_list.end()))
		{
			/* User doesn't have the status we're after */
			if (minrank && i->second->getRank() < minrank)
				continue;

			i->first->Write(out);
		}
	}
}

void Channel::WriteAllExceptSender(User* user, bool serversource, char status, const std::string& text)
{
	CUList except_list;
	except_list.insert(user);
	this->WriteAllExcept(user, serversource, status, except_list, std::string(text));
}

const char* Channel::ChanModes(bool showkey)
{
	static std::string scratch;
	std::string sparam;

	scratch.clear();

	/* This was still iterating up to 190, Channel::modes is only 64 elements -- Om */
	for(int n = 0; n < 64; n++)
	{
		ModeHandler* mh = ServerInstance->Modes->FindMode(n + 65, MODETYPE_CHANNEL);
		if (mh && IsModeSet(mh))
		{
			scratch.push_back(n + 65);

			ParamModeBase* pm = mh->IsParameterMode();
			if (!pm)
				continue;

			if (n == 'k' - 65 && !showkey)
			{
				sparam += " <key>";
			}
			else
			{
				sparam += ' ';
				pm->GetParameter(this, sparam);
			}
		}
	}

	scratch += sparam;
	return scratch.c_str();
}

/* compile a userlist of a channel into a string, each nick seperated by
 * spaces and op, voice etc status shown as @ and +, and send it to 'user'
 */
void Channel::UserList(User *user)
{
	bool has_privs = user->HasPrivPermission("channels/auspex");
	if (this->IsModeSet(secretmode) && !this->HasUser(user) && !has_privs)
	{
		user->WriteNumeric(ERR_NOSUCHNICK, "%s :No such nick/channel", this->name.c_str());
		return;
	}

	std::string list;
	list.push_back(this->IsModeSet(secretmode) ? '@' : this->IsModeSet(privatemode) ? '*' : '=');
	list.push_back(' ');
	list.append(this->name).append(" :");
	std::string::size_type pos = list.size();

	bool has_one = false;

	/* Improvement by Brain - this doesnt change in value, so why was it inside
	 * the loop?
	 */
	bool has_user = this->HasUser(user);

	std::string prefixlist;
	std::string nick;
	for (UserMembIter i = userlist.begin(); i != userlist.end(); ++i)
	{
		if ((!has_user) && (i->first->IsModeSet(invisiblemode)) && (!has_privs))
		{
			/*
			 * user is +i, and source not on the channel, does not show
			 * nick in NAMES list
			 */
			continue;
		}

		Membership* memb = i->second;

		prefixlist.clear();
		prefixlist.push_back(memb->GetPrefixChar());
		nick = i->first->nick;

		FOREACH_MOD(OnNamesListItem, (user, memb, prefixlist, nick));

		/* Nick was nuked, a module wants us to skip it */
		if (nick.empty())
			continue;

		if (list.size() + prefixlist.length() + nick.length() + 1 > 480)
		{
			/* list overflowed into multiple numerics */
			user->WriteNumeric(RPL_NAMREPLY, list);

			// Erase all nicks, keep the constant part
			list.erase(pos);
			has_one = false;
		}

		list.append(prefixlist).append(nick).push_back(' ');

		has_one = true;
	}

	/* if whats left in the list isnt empty, send it */
	if (has_one)
	{
		user->WriteNumeric(RPL_NAMREPLY, list);
	}

	user->WriteNumeric(RPL_ENDOFNAMES, "%s :End of /NAMES list.", this->name.c_str());
}

/* returns the status character for a given user on a channel, e.g. @ for op,
 * % for halfop etc. If the user has several modes set, the highest mode
 * the user has must be returned.
 */
char Membership::GetPrefixChar() const
{
	char pf = 0;
	unsigned int bestrank = 0;

	for (std::string::const_iterator i = modes.begin(); i != modes.end(); ++i)
	{
		PrefixMode* mh = ServerInstance->Modes->FindPrefixMode(*i);
		if (mh && mh->GetPrefixRank() > bestrank && mh->GetPrefix())
		{
			bestrank = mh->GetPrefixRank();
			pf = mh->GetPrefix();
		}
	}
	return pf;
}

unsigned int Membership::getRank()
{
	char mchar = modes.c_str()[0];
	unsigned int rv = 0;
	if (mchar)
	{
		PrefixMode* mh = ServerInstance->Modes->FindPrefixMode(mchar);
		if (mh)
			rv = mh->GetPrefixRank();
	}
	return rv;
}

const char* Membership::GetAllPrefixChars() const
{
	static char prefix[64];
	int ctr = 0;

	for (std::string::const_iterator i = modes.begin(); i != modes.end(); ++i)
	{
		PrefixMode* mh = ServerInstance->Modes->FindPrefixMode(*i);
		if (mh && mh->GetPrefix())
			prefix[ctr++] = mh->GetPrefix();
	}
	prefix[ctr] = 0;

	return prefix;
}

unsigned int Channel::GetPrefixValue(User* user)
{
	UserMembIter m = userlist.find(user);
	if (m == userlist.end())
		return 0;
	return m->second->getRank();
}

bool Membership::SetPrefix(PrefixMode* delta_mh, bool adding)
{
	char prefix = delta_mh->GetModeChar();
	for (unsigned int i = 0; i < modes.length(); i++)
	{
		char mchar = modes[i];
		PrefixMode* mh = ServerInstance->Modes->FindPrefixMode(mchar);
		if (mh && mh->GetPrefixRank() <= delta_mh->GetPrefixRank())
		{
			modes = modes.substr(0,i) +
				(adding ? std::string(1, prefix) : "") +
				modes.substr(mchar == prefix ? i+1 : i);
			return adding != (mchar == prefix);
		}
	}
	if (adding)
		modes.push_back(prefix);
	return adding;
}

void Invitation::Create(Channel* c, LocalUser* u, time_t timeout)
{
	if ((timeout != 0) && (ServerInstance->Time() >= timeout))
		// Expired, don't bother
		return;

	ServerInstance->Logs->Log("INVITATION", LOG_DEBUG, "Invitation::Create chan=%s user=%s", c->name.c_str(), u->uuid.c_str());

	Invitation* inv = Invitation::Find(c, u, false);
	if (inv)
	{
		 if ((inv->expiry == 0) || (inv->expiry > timeout))
			return;
		inv->expiry = timeout;
		ServerInstance->Logs->Log("INVITATION", LOG_DEBUG, "Invitation::Create changed expiry in existing invitation %p", (void*) inv);
	}
	else
	{
		inv = new Invitation(c, u, timeout);
		c->invites.push_front(inv);
		u->invites.push_front(inv);
		ServerInstance->Logs->Log("INVITATION", LOG_DEBUG, "Invitation::Create created new invitation %p", (void*) inv);
	}
}

Invitation* Invitation::Find(Channel* c, LocalUser* u, bool check_expired)
{
	ServerInstance->Logs->Log("INVITATION", LOG_DEBUG, "Invitation::Find chan=%s user=%s check_expired=%d", c ? c->name.c_str() : "NULL", u ? u->uuid.c_str() : "NULL", check_expired);
	if (!u || u->invites.empty())
		return NULL;

	Invitation* result = NULL;
	for (InviteList::iterator i = u->invites.begin(); i != u->invites.end(); )
	{
		Invitation* inv = *i;
		++i;

		if ((check_expired) && (inv->expiry != 0) && (inv->expiry <= ServerInstance->Time()))
		{
			/* Expired invite, remove it. */
			std::string expiration = InspIRCd::TimeString(inv->expiry);
			ServerInstance->Logs->Log("INVITATION", LOG_DEBUG, "Invitation::Find ecountered expired entry: %p expired %s", (void*) inv, expiration.c_str());
			delete inv;
		}
		else
		{
			/* Is it what we're searching for? */
			if (inv->chan == c)
			{
				result = inv;
				break;
			}
		}
	}

	ServerInstance->Logs->Log("INVITATION", LOG_DEBUG, "Invitation::Find result=%p", (void*) result);
	return result;
}

Invitation::~Invitation()
{
	// Remove this entry from both lists
	chan->invites.erase(this);
	user->invites.erase(this);
	ServerInstance->Logs->Log("INVITEBASE", LOG_DEBUG, "Invitation::~ %p", (void*) this);
}