/*       +------------------------------------+
 *       | 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 <stdarg.h>

/* $ModDesc: Allows for opered clients to join channels without being seen, similar to unreal 3.1 +I mode */
/* $ModDepends: core 2.0 */

class InvisibleMode : public ModeHandler
{
 public:
	InvisibleMode(Module* Creator) : ModeHandler(Creator, "invis-oper", 'Q', PARAM_NONE, MODETYPE_USER)
	{
		oper = true;
	}

	~InvisibleMode()
	{
	}

	ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string &parameter, bool adding)
	{
		if (dest->IsModeSet('Q') != adding)
		{
			dest->SetMode('Q', adding);

			/* Fix for bug #379 reported by stealth. On +/-Q make m_watch think the user has signed on/off */
			Module* m = ServerInstance->Modules->Find("m_watch.so");

			/* This must come before setting/unsetting the handler */
			if (m && adding)
				m->OnUserQuit(dest, "Connection closed", "Connection closed");

			/* User appears to vanish or appear from nowhere */
			for (UCListIter f = dest->chans.begin(); f != dest->chans.end(); f++)
			{
				const UserMembList *ulist = (*f)->GetUsers();
				char tb[MAXBUF];

				snprintf(tb,MAXBUF,":%s %s %s", dest->GetFullHost().c_str(), adding ? "PART" : "JOIN", (*f)->name.c_str());
				std::string out = tb;
				Membership* memb = (**f).GetUser(dest);
				std::string ms = memb->modes;
				for(unsigned int i=0; i < memb->modes.length(); i++)
					ms.append(" ").append(dest->nick);


				for (UserMembCIter i = ulist->begin(); i != ulist->end(); i++)
				{
					/* User only appears to vanish for non-opers */
					if (IS_LOCAL(i->first) && !IS_OPER(i->first))
					{
						i->first->Write(out);
						if (!ms.empty() && !adding)
							i->first->WriteServ("MODE %s +%s", (**f).name.c_str(), ms.c_str());
					}
				}
			}

			ServerInstance->SNO->WriteToSnoMask('a', "\2NOTICE\2: Oper %s has become %svisible (%cQ)", dest->GetFullHost().c_str(), adding ? "in" : "", adding ? '+' : '-');
			return MODEACTION_ALLOW;
		}
		else
		{
			return MODEACTION_DENY;
		}
	}
};

class ModuleInvisible : public Module
{
 private:
	InvisibleMode qm;
	bool hidejoin;
	bool hidelist;
	bool hidemode;
	bool hidewho;
	bool hidemsg;
	bool hidewhois;
	bool hidestats;
	bool evade;
	bool safety;

	bool override_active;

 public:
	ModuleInvisible() : qm(this), override_active(false)
	{
	}

	void init()
	{
		ServerInstance->Modules->AddService(qm);

		/* Yeah i know people can take this out. I'm not about to obfuscate code just to be a pain in the ass. */
		ServerInstance->Users->ServerNoticeAll("*** m_invisible.so has just been loaded on this network. For more information, please visit http://inspircd.org/wiki/Modules/invisible");
		Implementation eventlist[] = {
			I_OnUserPreMessage, I_OnUserPreNotice, I_OnUserJoin,
			I_OnBuildNeighborList, I_OnSendWhoLine, I_OnNamesListItem,
			I_OnRehash, I_OnUserPreNotice, I_OnWhoisLine, I_OnRawMode,
			I_OnPreMode, I_OnUserPreNick, I_OnUserPart, I_OnStats, I_OnUserPreKick
		};
		ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
		OnRehash(NULL);
	}

	void OnRehash(User*)
	{
		ConfigTag* tag = ServerInstance->Config->ConfValue("invisible");
		hidejoin = tag->getBool("join", true);
		hidelist = tag->getBool("list", true);
		hidewho = tag->getBool("who", true);
		hidemsg = tag->getBool("msg", true);
		hidemode = tag->getBool("mode", true);
		hidewhois = tag->getBool("whois", true);
		hidestats = tag->getBool("stats", true);
		evade = tag->getBool("evade", true);
		safety = tag->getBool("safety", false);
	}

	Version GetVersion()
	{
		return Version("Allows opers to join channels invisibly", VF_COMMON);
	}

	static void BuildExcept(Membership* memb, CUList& excepts)
	{
		const UserMembList* users = memb->chan->GetUsers();
		for(UserMembCIter i = users->begin(); i != users->end(); i++)
			if (memb->user != i->first && IS_LOCAL(i->first) && !i->first->HasPrivPermission("invisible/see"))
				excepts.insert(i->first);
	}

	void OnUserJoin(Membership* memb, bool sync, bool created, CUList& excepts)
	{
		if (hidejoin && memb->user->IsModeSet('Q'))
		{
			BuildExcept(memb, excepts);
			ServerInstance->SNO->WriteToSnoMask('a', "\2NOTICE\2: Oper %s has joined %s invisibly (+Q)",
				memb->user->GetFullHost().c_str(), memb->chan->name.c_str());
		}
	}

	void OnUserPart(Membership* memb, std::string& partmessage, CUList& except_list)
	{
		if (memb->user->IsModeSet('Q'))
			BuildExcept(memb, except_list);
	}

	void OnBuildNeighborList(User* source, UserChanList &include, std::map<User*,bool> &exceptions)
	{
		if (hidewho && source->IsModeSet('Q'))
			include.clear();
	}

	ModResult OnUserPreKick(User* source, Membership* memb, const std::string& reason)
	{
		if (!hidemode || !IS_LOCAL(source) || !memb->user->IsModeSet('Q'))
			return MOD_RES_PASSTHRU;

		source->WriteNumeric(401, "%s %s :No such nick/channel", source->nick.c_str(), memb->user->nick.c_str());
		return MOD_RES_DENY;
	}

	ModResult OnStats(char symbol, User* user, std::vector<std::string>& results)
	{
		if (!hidestats || symbol != 'P')
			return MOD_RES_PASSTHRU;

		// Steal some logic from cmd_stats.cpp
		unsigned int idx = 0;
		std::string sn(ServerInstance->Config->ServerName);
		for (std::list<User*>::const_iterator i = ServerInstance->Users->all_opers.begin(); i != ServerInstance->Users->all_opers.end(); ++i)
		{
			User* oper = *i;
			if (!ServerInstance->ULine(oper->server) && !oper->IsModeSet('Q'))
			{
				results.push_back(sn+" 249 " + user->nick + " :" + oper->nick + " (" + oper->ident + "@" + oper->dhost + ") Idle: " +
						(IS_LOCAL(oper) ? ConvToStr(ServerInstance->Time() - oper->idle_lastmsg) + " secs" : "unavailable"));
				idx++;
			}
		}
		results.push_back(sn+" 249 "+user->nick+" :"+ConvToStr(idx)+" OPER(s)");

		return MOD_RES_DENY;
	}

	ModResult OnUserPreNick(User* user, const std::string& newnick)
	{
		User* nick = ServerInstance->FindNick(newnick);
		if (evade && nick && IS_LOCAL(user) && nick->IsModeSet('Q') && nick != user)
			// Hahaha you'll never catch me!
			nick->ChangeNick(nick->uuid);

		return MOD_RES_PASSTHRU;
	}

	ModResult OnRawMode(User* user, Channel* chan, const char mode, const std::string& param, bool adding, int pcnt)
	{
		if (!hidemode || override_active || !chan | !IS_LOCAL(user))
			return MOD_RES_PASSTHRU;

		User* nick = ServerInstance->FindNick(param);
		ModeHandler* mh = ServerInstance->Modes->FindMode(mode, MODETYPE_CHANNEL);
		if (!nick || !mh->GetPrefixRank())
			return MOD_RES_PASSTHRU;

		if (nick->IsModeSet('Q'))
		{
			user->WriteNumeric(401, "%s %s :No such nick/channel",user->nick.c_str(), param.c_str());
			return MOD_RES_DENY;
		}

		return MOD_RES_PASSTHRU;
	}

	ModResult OnPreMode(User* source, User* dest, Channel* channel, const std::vector<std::string>& parameters)
	{
		if (override_active || !IS_LOCAL(source))
			return MOD_RES_PASSTHRU;

		if (safety && channel && source->IsModeSet('Q'))
		{
			if (parameters.size() < 2 || parameters[1] != "!")
			{
				source->WriteServ("NOTICE %s :*** Blocked message. You are hidden and safety is on. Place ' ! ' between channel and modes to override.", source->nick.c_str());
				return MOD_RES_DENY;
			}

			std::vector<std::string> params = parameters;
			params.erase(params.begin() + 1);
			override_active = true;
			ServerInstance->Modes->Process(params, source);
			override_active = false;
			return MOD_RES_DENY;
		}
		return MOD_RES_PASSTHRU;
	}

	ModResult OnWhoisLine(User* user, User* dest, int& numeric, std::string& text)
	{
		if (!hidewhois || (!IS_OPER(user) && !dest->IsModeSet('Q')))
			return MOD_RES_PASSTHRU;

		if (numeric == 318)
			return MOD_RES_ALLOW;

		return MOD_RES_DENY;
	}

	/* No privmsg response when hiding - submitted by Eric at neowin */
	ModResult OnUserPreNotice(User* user,void* dest,int target_type, std::string &text, char status, CUList &exempt_list)
	{
		if (safety && IS_LOCAL(user) && user->IsModeSet('Q'))
		{
			// Don't block messages to other opers
			if (target_type == TYPE_USER && IS_OPER(static_cast<User*>(dest)))
				return MOD_RES_PASSTHRU;

			if (text[0] != '!')
			{
				user->WriteServ("NOTICE %s :*** Blocked message. You are hidden and safety is on. Prefix message with ! to override.", user->nick.c_str());
				return MOD_RES_DENY;
			}
			text = text.substr(1);
		}
		else if ((target_type == TYPE_USER) && (IS_LOCAL(user)))
		{
			User* target = (User*)dest;
			if(hidemsg && target->IsModeSet('Q') && !IS_OPER(user))
			{
				user->WriteNumeric(401, "%s %s :No such nick/channel",user->nick.c_str(), target->nick.c_str());
				return MOD_RES_DENY;
			}
		}
		return MOD_RES_PASSTHRU;
	}

	ModResult OnUserPreMessage(User* user,void* dest,int target_type, std::string &text, char status, CUList &exempt_list)
	{
		return OnUserPreNotice(user, dest, target_type, text, status, exempt_list);
	}

	void OnSendWhoLine(User* source, const std::vector<std::string>& params, User* user, std::string& line)
	{
		if (hidewho && user->IsModeSet('Q') && !IS_OPER(source))
			line.clear();
	}

	void OnNamesListItem(User* issuer, Membership* memb, std::string &prefixes, std::string &nick)
	{
		if (hidelist && memb->user->IsModeSet('Q') && !IS_OPER(issuer))
			nick.clear();
	}
};

MODULE_INIT(ModuleInvisible)