/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2018 linuxdaemon <linuxdaemon.irc@gmail.com>
 *   Copyright (C) 2013, 2017-2018, 2020 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2012-2013 Attila Molnar <attilamolnar@hush.com>
 *   Copyright (C) 2012, 2019 Robby <robby@chatbelgie.be>
 *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
 *   Copyright (C) 2008 Thomas Stagner <aquanight@inspircd.org>
 *   Copyright (C) 2007-2008 Robin Burchell <robin+git@viroteck.net>
 *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
 *   Copyright (C) 2006, 2010 Craig Edwards <brain@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 "modules/exemption.h"

typedef insp::flat_map<std::string, std::string, irc::insensitive_swo> censor_t;

class ModuleCensor : public Module
{
 private:
	CheckExemption::EventProvider exemptionprov;
	censor_t censors;
	SimpleUserModeHandler cu;
	SimpleChannelModeHandler cc;

 public:
	ModuleCensor()
		: Module(VF_VENDOR, "Allows the server administrator to define inappropriate phrases that are not allowed to be used in private or channel messages.")
		, exemptionprov(this)
		, cu(this, "u_censor", 'G')
		, cc(this, "censor", 'G')
	{
	}

	// format of a config entry is <badword text="shit" replace="poo">
	ModResult OnUserPreMessage(User* user, const MessageTarget& target, MessageDetails& details) override
	{
		if (!IS_LOCAL(user))
			return MOD_RES_PASSTHRU;

		switch (target.type)
		{
			case MessageTarget::TYPE_USER:
			{
				User* targuser = target.Get<User>();
				if (!targuser->IsModeSet(cu))
					return MOD_RES_PASSTHRU;
				break;
			}

			case MessageTarget::TYPE_CHANNEL:
			{
				Channel* targchan = target.Get<Channel>();
				if (!targchan->IsModeSet(cc))
					return MOD_RES_PASSTHRU;

				ModResult result = CheckExemption::Call(exemptionprov, user, targchan, "censor");
				if (result == MOD_RES_ALLOW)
					return MOD_RES_PASSTHRU;
				break;
			}

			default:
				return MOD_RES_PASSTHRU;
		}

		for (censor_t::iterator index = censors.begin(); index != censors.end(); index++)
		{
			size_t censorpos;
			while ((censorpos = irc::find(details.text, index->first)) != std::string::npos)
			{
				if (index->second.empty())
				{
					const std::string msg = InspIRCd::Format("Your message to this channel contained a banned phrase (%s) and was blocked.", index->first.c_str());
					if (target.type == MessageTarget::TYPE_CHANNEL)
						user->WriteNumeric(Numerics::CannotSendTo(target.Get<Channel>(), msg));
					else
						user->WriteNumeric(Numerics::CannotSendTo(target.Get<User>(), msg));
					return MOD_RES_DENY;
				}

				details.text.replace(censorpos, index->first.size(), index->second);
			}
		}
		return MOD_RES_PASSTHRU;
	}

	void ReadConfig(ConfigStatus& status) override
	{
		/*
		 * reload our config file on rehash - we must destroy and re-allocate the classes
		 * to call the constructor again and re-read our data.
		 */
		censor_t newcensors;

		for (auto& [_, tag] : ServerInstance->Config->ConfTags("badword"))
		{
			const std::string text = tag->getString("text");
			if (text.empty())
				throw ModuleException("<badword:text> is empty! at " + tag->source.str());

			const std::string replace = tag->getString("replace");
			newcensors[text] = replace;
		}
		censors.swap(newcensors);
	}
};

MODULE_INIT(ModuleCensor)
