/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2019 linuxdaemon <linuxdaemon.irc@gmail.com>
 *   Copyright (C) 2018, 2021-2022 Sadie Powell <sadie@witchery.services>
 *
 * 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/>.
 */


#pragma once

namespace Who
{
	class EventListener;
	class MatchEventListener;
	class VisibleEventListener;
	class Request;
}

class Who::EventListener
	: public Events::ModuleEventListener
{
public:
	EventListener(Module* mod)
		: ModuleEventListener(mod, "event/who")
	{
	}

	/** Called when a result from WHO is about to be queued.
	 * @param request Details about the WHO request which caused this response.
	 * @param source The user who initiated this WHO request.
	 * @param user The user that this line of the WHO request is about.
	 * @param memb The channel membership of the user or the first visible membership if not targeted at a channel.
	 * @param numeric The numeric which will be sent in response to the request.
	 * @return MOD_RES_ALLOW to explicitly allow the response, MOD_RES_DENY to explicitly deny the
	 *         response, or MOD_RES_PASSTHRU to let another module handle the event.
	 */
	virtual ModResult OnWhoLine(const Request& request, LocalUser* source, User* user, Membership* memb, Numeric::Numeric& numeric) = 0;
};

class Who::MatchEventListener
	: public Events::ModuleEventListener
{
public:
	MatchEventListener(Module* mod)
		: ModuleEventListener(mod, "event/who-match")
	{
	}

	/** Called when a WHO request needs to check if a user matches it.
	 * @param request Details about the WHO request which caused this match attempt.
	 * @param source The user who initiated this WHO request.
	 * @param user The user to attempt to match the WHO request against.
	 * @return MOD_RES_ALLOW to explicitly allow the match, MOD_RES_DENY to explicitly deny the
	 *         match, or MOD_RES_PASSTHRU to let another module handle the event.
	 */
	virtual ModResult OnWhoMatch(const Request& request, LocalUser* source, User* user) = 0;
};

class Who::VisibleEventListener
	: public Events::ModuleEventListener
{
public:
	VisibleEventListener(Module* mod)
		: ModuleEventListener(mod, "event/who-visible")
	{
	}

	/** Called when a WHO request needs to check if a channel is visible.
	 * @param request Details about the WHO request which caused this match attempt.
	 * @param source The user who initiated this WHO request.
	 * @param memb The channel membership of the user to check the visibility of.
	 * @return MOD_RES_ALLOW to explicitly allow the match, MOD_RES_DENY to explicitly deny the
	 *         match, or MOD_RES_PASSTHRU to let another module handle the event.
	 */
	virtual ModResult OnWhoVisible(const Request& request, LocalUser* source, Membership* memb) = 0;
};

class Who::Request
{
public:
	/** The flags for matching users to include. */
	CharState flags;

	/** Whether we are matching using a wildcard or a flag. */
	bool fuzzy_match = false;

	/** The text to match against. */
	std::string matchtext;

	/** If the target was a channel then the matched channel */
	Channel* matchchan = nullptr;

	/** The WHO/WHOX responses we will send to the source. */
	std::vector<Numeric::Numeric> results;

	/** Whether the source requested a WHOX response. */
	bool whox = false;

	/** The fields to include in the WHOX response. */
	CharState whox_fields;

	/** A user specified label for the WHOX response. */
	std::string whox_querytype;

	/** Get the index in the response parameters for the different data fields
	 *
	 * The fields 'r' (realname) and 'd' (hops) will always be missing in a non-WHOX
	 * query, because WHOX splits them to 2 fields, where old WHO has them as one.
	 *
	 * @param flag The field name to look for
	 * @param out The index will be stored in this value
	 * @return True if the field is available, false otherwise
	 */
	virtual bool GetFieldIndex(char flag, size_t& out) const = 0;

protected:
	Request() = default;
};