/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2009 Daniel De Graaf <danieldg@inspircd.org>
 *   Copyright (C) 2008 Pippijn van Steenhoven <pip88nl@gmail.com>
 *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
 *   Copyright (C) 2007 Robin Burchell <robin+git@viroteck.net>
 *   Copyright (C) 2006-2007 Oliver Lupton <oliverlupton@gmail.com>
 *
 * 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"

/* $ModDesc: Attempt to block /amsg, at least some of the irritating mIRC scripts. */

enum BlockAction { IBLOCK_KILL, IBLOCK_KILLOPERS, IBLOCK_NOTICE, IBLOCK_NOTICEOPERS, IBLOCK_SILENT };
/*	IBLOCK_NOTICE		- Send a notice to the user informing them of what happened.
 *	IBLOCK_NOTICEOPERS	- Send a notice to the user informing them and send an oper notice.
 *	IBLOCK_SILENT		- Generate no output, silently drop messages.
 *	IBLOCK_KILL			- Kill the user with the reason "Global message (/amsg or /ame) detected".
 *	IBLOCK_KILLOPERS	- As above, but send an oper notice as well. This is the default.
 */

/** Holds a blocked message's details
 */
class BlockedMessage
{
 public:
	std::string message;
	irc::string target;
	time_t sent;

	BlockedMessage(const std::string &msg, const irc::string &tgt, time_t when)
	: message(msg), target(tgt), sent(when)
	{
	}
};

class ModuleBlockAmsg : public Module
{
	int ForgetDelay;
	BlockAction action;
	SimpleExtItem<BlockedMessage> blockamsg;

 public:
	ModuleBlockAmsg() : blockamsg("blockamsg", this)
	{
	}

	void init() CXX11_OVERRIDE
	{
		this->OnRehash(NULL);
		ServerInstance->Modules->AddService(blockamsg);
		Implementation eventlist[] = { I_OnRehash, I_OnPreCommand };
		ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
	}

	Version GetVersion() CXX11_OVERRIDE
	{
		return Version("Attempt to block /amsg, at least some of the irritating mIRC scripts.",VF_VENDOR);
	}

	void OnRehash(User* user) CXX11_OVERRIDE
	{
		ConfigTag* tag = ServerInstance->Config->ConfValue("blockamsg");
		ForgetDelay = tag->getInt("delay", -1);
		std::string act = tag->getString("action");

		if(act == "notice")
			action = IBLOCK_NOTICE;
		else if(act == "noticeopers")
			action = IBLOCK_NOTICEOPERS;
		else if(act == "silent")
			action = IBLOCK_SILENT;
		else if(act == "kill")
			action = IBLOCK_KILL;
		else
			action = IBLOCK_KILLOPERS;
	}

	ModResult OnPreCommand(std::string &command, std::vector<std::string> &parameters, LocalUser *user, bool validated, const std::string &original_line) CXX11_OVERRIDE
	{
		// Don't do anything with unregistered users
		if (user->registered != REG_ALL)
			return MOD_RES_PASSTHRU;

		if ((validated) && (parameters.size() >= 2) && ((command == "PRIVMSG") || (command == "NOTICE")))
		{
			// parameters[0] should have the target(s) in it.
			// I think it will be faster to first check if there are any commas, and if there are then try and parse it out.
			// Most messages have a single target so...

			int targets = 1;
			int userchans = 0;

			if(*parameters[0].c_str() != '#')
			{
				// Decrement if the first target wasn't a channel.
				targets--;
			}

			for(const char* c = parameters[0].c_str(); *c; c++)
				if((*c == ',') && *(c+1) && (*(c+1) == '#'))
					targets++;

			/* targets should now contain the number of channel targets the msg/notice was pointed at.
			 * If the msg/notice was a PM there should be no channel targets and 'targets' should = 0.
			 * We don't want to block PMs so...
			 */
			if(targets == 0)
			{
				return MOD_RES_PASSTHRU;
			}

			userchans = user->chans.size();

			// Check that this message wasn't already sent within a few seconds.
			BlockedMessage* m = blockamsg.get(user);

			// If the message is identical and within the time.
			// We check the target is *not* identical, that'd straying into the realms of flood control. Which isn't what we're doing...
			// OR
			// The number of target channels is equal to the number of channels the sender is on..a little suspicious.
			// Check it's more than 1 too, or else users on one channel would have fun.
			if((m && (m->message == parameters[1]) && (m->target != parameters[0]) && (ForgetDelay != -1) && (m->sent >= ServerInstance->Time()-ForgetDelay)) || ((targets > 1) && (targets == userchans)))
			{
				// Block it...
				if(action == IBLOCK_KILLOPERS || action == IBLOCK_NOTICEOPERS)
					ServerInstance->SNO->WriteToSnoMask('a', "%s had an /amsg or /ame denied", user->nick.c_str());

				if(action == IBLOCK_KILL || action == IBLOCK_KILLOPERS)
					ServerInstance->Users->QuitUser(user, "Attempted to global message (/amsg or /ame)");
				else if(action == IBLOCK_NOTICE || action == IBLOCK_NOTICEOPERS)
					user->WriteServ( "NOTICE %s :Global message (/amsg or /ame) denied", user->nick.c_str());

				return MOD_RES_DENY;
			}

			if(m)
			{
				// If there's already a BlockedMessage allocated, use it.
				m->message = parameters[1];
				m->target = parameters[0].c_str();
				m->sent = ServerInstance->Time();
			}
			else
			{
				m = new BlockedMessage(parameters[1], parameters[0].c_str(), ServerInstance->Time());
				blockamsg.set(user, m);
			}
		}
		return MOD_RES_PASSTHRU;
	}
};

MODULE_INIT(ModuleBlockAmsg)
