/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2017 B00mX0r <b00mx0r@aureus.pw>
 *   Copyright (C) 2013, 2018, 2020, 2022 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2012-2013, 2016, 2018 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) 2007 Robin Burchell <robin+git@viroteck.net>
 *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
 *   Copyright (C) 2004, 2006, 2008 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/invite.h"

enum
{
	// From UnrealIRCd.
	ERR_CANNOTKNOCK = 480,

	// From ircd-ratbox.
	RPL_KNOCK = 710,
	RPL_KNOCKDLVR = 711,
	ERR_CHANOPEN = 713,
	ERR_KNOCKONCHAN = 714
};

/** Handles the /KNOCK command
 */
class CommandKnock : public Command
{
 private:
	SimpleChannelModeHandler& noknockmode;
	ChanModeReference inviteonlymode;
	Invite::API inviteapi;

 public:
	bool sendnotice;
	bool sendnumeric;
	CommandKnock(Module* Creator, SimpleChannelModeHandler& Noknockmode)
		: Command(Creator,"KNOCK", 2, 2)
		, noknockmode(Noknockmode)
		, inviteonlymode(Creator, "inviteonly")
		, inviteapi(Creator)
	{
		syntax = "<channel> :<reason>";
		Penalty = 5;
	}

	CmdResult Handle(User* user, const Params& parameters) CXX11_OVERRIDE
	{
		Channel* c = ServerInstance->FindChan(parameters[0]);
		if (!c)
		{
			user->WriteNumeric(Numerics::NoSuchChannel(parameters[0]));
			return CMD_FAILURE;
		}

		if (c->HasUser(user))
		{
			user->WriteNumeric(ERR_KNOCKONCHAN, c->name, InspIRCd::Format("Can't KNOCK on %s, you are already on that channel.", c->name.c_str()));
			return CMD_FAILURE;
		}

		if (c->IsModeSet(noknockmode))
		{
			user->WriteNumeric(ERR_CANNOTKNOCK, InspIRCd::Format("Can't KNOCK on %s, +K is set.", c->name.c_str()));
			return CMD_FAILURE;
		}

		if (!c->IsModeSet(inviteonlymode))
		{
			user->WriteNumeric(ERR_CHANOPEN, c->name, InspIRCd::Format("Can't KNOCK on %s, channel is not invite only so knocking is pointless!", c->name.c_str()));
			return CMD_FAILURE;
		}

		// Work out who we should send the knock to.
		char status;
		switch (inviteapi->GetAnnounceState())
		{
			case Invite::ANNOUNCE_ALL:
			{
				status = 0;
				break;
			}

			case Invite::ANNOUNCE_DYNAMIC:
			{
				PrefixMode* mh = ServerInstance->Modes.FindNearestPrefixMode(HALFOP_VALUE);
				status = mh->GetPrefix() ? mh->GetPrefix() : '@';
				break;
			}

			default:
			{
				status = '@';
				break;
			}
		}

		if (sendnotice)
		{
			c->WriteNotice(InspIRCd::Format("User %s is KNOCKing on %s (%s)", user->nick.c_str(), c->name.c_str(), parameters[1].c_str()), status);
			user->WriteNotice("KNOCKing on " + c->name);
		}

		if (sendnumeric)
		{
			Numeric::Numeric numeric(RPL_KNOCK);
			numeric.push(c->name).push(user->GetFullHost()).push("is KNOCKing: " + parameters[1]);

			ClientProtocol::Messages::Numeric numericmsg(numeric, c->name);
			c->Write(ServerInstance->GetRFCEvents().numeric, numericmsg, status);

			user->WriteNumeric(RPL_KNOCKDLVR, c->name, "KNOCKing on channel");
		}

		return CMD_SUCCESS;
	}

	RouteDescriptor GetRouting(User* user, const Params& parameters) CXX11_OVERRIDE
	{
		return ROUTE_OPT_BCAST;
	}
};

class ModuleKnock : public Module
{
	SimpleChannelModeHandler kn;
	CommandKnock cmd;

 public:
	ModuleKnock()
		: kn(this, "noknock", 'K')
		, cmd(this, kn)
	{
	}

	void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
	{
		std::string knocknotify = ServerInstance->Config->ConfValue("knock")->getString("notify");
		if (stdalgo::string::equalsci(knocknotify, "numeric"))
		{
			cmd.sendnotice = false;
			cmd.sendnumeric = true;
		}
		else if (stdalgo::string::equalsci(knocknotify, "both"))
		{
			cmd.sendnotice = true;
			cmd.sendnumeric = true;
		}
		else
		{
			cmd.sendnotice = true;
			cmd.sendnumeric = false;
		}
	}

	Version GetVersion() CXX11_OVERRIDE
	{
		return Version("Adds the /KNOCK command which allows users to request access to an invite-only channel and channel mode K (noknock) which allows channels to disable usage of this command.", VF_OPTCOMMON | VF_VENDOR);
	}
};

MODULE_INIT(ModuleKnock)
