/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2020 Michael <michaelhazell@hotmail.com>
 *   Copyright (C) 2019 Matt Schatz <genius3000@g3k.solutions>
 *   Copyright (C) 2018 linuxdaemon <linuxdaemon.irc@gmail.com>
 *   Copyright (C) 2013, 2017-2018, 2020, 2022 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2012-2013, 2016 Attila Molnar <attilamolnar@hush.com>
 *   Copyright (C) 2012, 2019 Robby <robby@chatbelgie.be>
 *   Copyright (C) 2009 John Brooks <special@inspircd.org>
 *   Copyright (C) 2009 Daniel De Graaf <danieldg@inspircd.org>
 *   Copyright (C) 2007-2008 Dennis Friis <peavey@inspircd.org>
 *   Copyright (C) 2006 Craig Edwards <brain@inspircd.org>
 *   Copyright (C) 2005, 2008 Robin Burchell <robin+git@viroteck.net>
 *
 * 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/stats.h"
#include "timeutils.h"
#include "xline.h"

enum
{
	// InspIRCd-specific.
	ERR_BADCHANNEL = 926
};

/** Holds a CBAN item
 */
class CBan final
	: public XLine
{
private:
	std::string matchtext;

public:
	CBan(time_t s_time, unsigned long d, const std::string& src, const std::string& re, const std::string& ch)
		: XLine(s_time, d, src, re, "CBAN")
		, matchtext(ch)
	{
	}

	// XXX I shouldn't have to define this
	bool Matches(User* u) const override
	{
		return false;
	}

	bool Matches(const std::string& s) const override
	{
		return InspIRCd::Match(s, matchtext);
	}

	const std::string& Displayable() const override
	{
		return matchtext;
	}
};

/** An XLineFactory specialized to generate cban pointers
 */
class CBanFactory final
	: public XLineFactory
{
public:
	CBanFactory()
		: XLineFactory("CBAN")
	{
	}

	XLine* Generate(time_t set_time, unsigned long duration, const std::string& source, const std::string& reason, const std::string& xline_specific_mask) override
	{
		return new CBan(set_time, duration, source, reason, xline_specific_mask);
	}

	bool AutoApplyToUserList(XLine* x) override
	{
		return false; // No, we apply to channels.
	}
};

class CommandCBan final
	: public Command
{
public:
	CommandCBan(Module* Creator)
		: Command(Creator, "CBAN", 1, 3)
	{
		access_needed = CmdAccess::OPERATOR;
		syntax = { "<channelmask> [<duration> [:<reason>]]" };
	}

	CmdResult Handle(User* user, const Params& parameters) override
	{
		/* syntax: CBAN #channel time :reason goes here */
		/* 'time' is a human-readable timestring, like 2d3h2s. */

		if (parameters.size() == 1)
		{
			std::string reason;

			if (ServerInstance->XLines->DelLine(parameters[0], "CBAN", reason, user))
			{
				ServerInstance->SNO.WriteToSnoMask('x', "{} removed CBan on {}: {}", user->nick, parameters[0], reason);
			}
			else
			{
				user->WriteNotice("*** CBan " + parameters[0] + " not found on the list.");
				return CmdResult::FAILURE;
			}
		}
		else
		{
			// Adding - XXX todo make this respect <insane> tag perhaps..
			unsigned long duration;
			if (!Duration::TryFrom(parameters[1], duration))
			{
				user->WriteNotice("*** Invalid duration for CBan.");
				return CmdResult::FAILURE;
			}

			const char* reason = (parameters.size() > 2) ? parameters[2].c_str() : "No reason supplied";
			auto* r = new CBan(ServerInstance->Time(), duration, user->nick, reason, parameters[0]);
			if (ServerInstance->XLines->AddLine(r, user))
			{
				if (!duration)
				{
					ServerInstance->SNO.WriteToSnoMask('x', "{} added a permanent CBan on {}: {}", user->nick, parameters[0], reason);
				}
				else
				{
					ServerInstance->SNO.WriteToSnoMask('x', "{} added a timed CBan on {}, expires in {} (on {}): {}",
						user->nick, parameters[0], Duration::ToString(duration),
						Time::ToString(ServerInstance->Time() + duration), reason);
				}
			}
			else
			{
				delete r;
				user->WriteNotice("*** CBan for " + parameters[0] + " already exists");
				return CmdResult::FAILURE;
			}
		}
		return CmdResult::SUCCESS;
	}
};

class ModuleCBan final
	: public Module
	, public Stats::EventListener
{
	CommandCBan mycommand;
	CBanFactory f;

public:
	ModuleCBan()
		: Module(VF_VENDOR | VF_COMMON, "Adds the /CBAN command which allows server operators to prevent channels matching a glob from being created.")
		, Stats::EventListener(this)
		, mycommand(this)
	{
	}

	void init() override
	{
		ServerInstance->XLines->RegisterFactory(&f);
	}

	~ModuleCBan() override
	{
		ServerInstance->XLines->DelAll("CBAN");
		ServerInstance->XLines->UnregisterFactory(&f);
	}

	ModResult OnStats(Stats::Context& stats) override
	{
		if (stats.GetSymbol() != 'C')
			return MOD_RES_PASSTHRU;

		ServerInstance->XLines->InvokeStats("CBAN", stats);
		return MOD_RES_DENY;
	}

	ModResult OnUserPreJoin(LocalUser* user, Channel* chan, const std::string& cname, std::string& privs, const std::string& keygiven, bool override) override
	{
		if (override)
			return MOD_RES_PASSTHRU;

		XLine* rl = ServerInstance->XLines->MatchesLine("CBAN", cname);
		if (rl)
		{
			// Channel is banned.
			user->WriteNumeric(ERR_BADCHANNEL, cname, INSP_FORMAT("Channel {} is CBANed: {}", cname, rl->reason));
			ServerInstance->SNO.WriteGlobalSno('a', "{} tried to join {} which is CBANed ({})",
				user->nick, cname, rl->reason);
			return MOD_RES_DENY;
		}

		return MOD_RES_PASSTHRU;
	}

	void GetLinkData(LinkData& data, std::string& compatdata) override
	{
		// It is assumed that if a server can speak the v4 protocol it can also
		// handle glob patterns for channel bans.
		compatdata.assign("glob");
	}
};

MODULE_INIT(ModuleCBan)