/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2012-2015, 2018 Attila Molnar <attilamolnar@hush.com>
 *   Copyright (C) 2012-2013, 2017-2018, 2020 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2012 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/>.
 */


#pragma once

/** Used to indicate the result of trying to execute a command. */
enum CmdResult
{
	/** The command exists but its execution failed. */
	CMD_FAILURE = 0,

	/** The command exists and its execution succeeded. */
	CMD_SUCCESS = 1,

	/* The command does not exist. */
	CMD_INVALID = 2
};

/** Flag for commands that are only allowed from servers */
const char FLAG_SERVERONLY = 7; // technically anything nonzero below 'A' works

/** Translation types for translation of parameters to UIDs.
 * This allows the core commands to not have to be aware of how UIDs
 * work (making it still possible to write other linking modules which
 * do not use UID (but why would you want to?)
 */
enum TranslateType
{
	TR_TEXT,		/* Raw text, leave as-is */
	TR_NICK,		/* Nickname, translate to UUID for server->server */
	TR_CUSTOM		/* Custom translation handled by EncodeParameter/DecodeParameter */
};

/** Routing types for a command. Any command which is created defaults
 * to having its command broadcasted on success. This behaviour may be
 * overridden to one of the route types shown below (see the #defines
 * below for more information on each one's behaviour)
 */
enum RouteType
{
	ROUTE_TYPE_LOCALONLY,
	ROUTE_TYPE_BROADCAST,
	ROUTE_TYPE_UNICAST,
	ROUTE_TYPE_MESSAGE,
	ROUTE_TYPE_OPT_BCAST,
	ROUTE_TYPE_OPT_UCAST
};

/** Defines routing information for a command, containing a destination
 * server id (if applicable) and a routing type from the enum above.
 */
struct RouteDescriptor
{
	/** Routing type from the enum above
	 */
	RouteType type;
	/** For unicast, the destination server's name
	 */
	std::string serverdest;

	/** For unicast, the destination Server
	 */
	Server* server;

	/** Create a RouteDescriptor
	 */
	RouteDescriptor(RouteType t, const std::string &d)
		: type(t), serverdest(d), server(NULL) { }

	RouteDescriptor(RouteType t, Server* srv)
		: type(t), server(srv) { }
};

/** Do not route this command */
#define ROUTE_LOCALONLY (RouteDescriptor(ROUTE_TYPE_LOCALONLY, ""))
/** Route this command to all servers, fail if not understood */
#define ROUTE_BROADCAST (RouteDescriptor(ROUTE_TYPE_BROADCAST, ""))
/** Route this command to a single server (do nothing if own server name specified) */
#define ROUTE_UNICAST(x) (RouteDescriptor(ROUTE_TYPE_UNICAST, x))
/** Route this command as a message with the given target (any of user, #channel, @#channel, $servermask) */
#define ROUTE_MESSAGE(x) (RouteDescriptor(ROUTE_TYPE_MESSAGE, x))
/** Route this command to all servers wrapped via ENCAP, so ignored if not understood */
#define ROUTE_OPT_BCAST (RouteDescriptor(ROUTE_TYPE_OPT_BCAST, ""))
/** Route this command to a single server wrapped via ENCAP, so ignored if not understood */
#define ROUTE_OPT_UCAST(x) (RouteDescriptor(ROUTE_TYPE_OPT_UCAST, x))

/** A structure that defines a command. Every command available
 * in InspIRCd must be defined as derived from Command.
 */
class CoreExport CommandBase : public ServiceProvider
{
 public:
	/** Encapsulates parameters to a command. */
	class Params : public std::vector<std::string>
	{
	 private:
		/* IRCv3 message tags. */
		ClientProtocol::TagMap tags;

	 public:
		/** Initializes a new instance from parameter and tag references.
		 * @param paramsref Message parameters.
		 * @param tagsref IRCv3 message tags.
		 */
		Params(const std::vector<std::string>& paramsref, const ClientProtocol::TagMap& tagsref)
			: std::vector<std::string>(paramsref)
			, tags(tagsref)
		{
		}

		/** Initializes a new instance from parameter iterators.
		 * @param first The first element in the parameter array.
		 * @param last The last element in the parameter array.
		 */
		template<typename Iterator>
		Params(Iterator first, Iterator last)
			: std::vector<std::string>(first, last)
		{
		}

		/** Initializes a new empty instance. */
		Params() { }

		/** Retrieves the IRCv3 message tags. */
		const ClientProtocol::TagMap& GetTags() const { return tags; }
	};

	/** Minimum number of parameters command takes
	*/
	const unsigned int min_params;

	/** Maximum number of parameters command takes.
	 * This is used by the command parser to join extra parameters into one last param.
	 * If not set, no munging is done to this command.
	 */
	const unsigned int max_params;

	/** True if the command allows an empty last parameter.
	 * When false and the last parameter is empty, it's popped BEFORE
	 * checking there are enough params, etc. (i.e. the handler won't
	 * be called if there aren't enough params after popping the empty
	 * param).
	 * True by default
	 */
	bool allow_empty_last_param;

	/** Translation type list for possible parameters, used to tokenize
	 * parameters into UIDs and SIDs etc.
	 */
	std::vector<TranslateType> translation;

	/** Create a new command.
	 * @param me The module which created this command.
	 * @param cmd Command name. This must be UPPER CASE.
	 * @param minpara Minimum parameters required for the command.
	 * @param maxpara Maximum number of parameters this command may have - extra parameters
	 * will be tossed into one last space-separated param.
	 */
	CommandBase(Module* me, const std::string& cmd, unsigned int minpara = 0, unsigned int maxpara = 0);

	virtual RouteDescriptor GetRouting(User* user, const CommandBase::Params& parameters);

	/** Encode a parameter for server->server transmission.
	 * Used for parameters for which the translation type is TR_CUSTOM.
	 * @param parameter The parameter to encode. Can be modified in place.
	 * @param index The parameter index (0 == first parameter).
	 */
	virtual void EncodeParameter(std::string& parameter, unsigned int index);

	virtual ~CommandBase();
};

class CoreExport Command : public CommandBase
{
 protected:
	/** Initializes a new instance of the Command class.
	 * @param me The module which created this instance.
	 * @param cmd The name of the command.
	 * @param minpara The minimum number of parameters that the command accepts.
	 * @param maxpara The maximum number of parameters that the command accepts.
	 */
	Command(Module* me, const std::string& cmd, unsigned int minpara = 0, unsigned int maxpara = 0);

 public:
	/** Unregisters this command from the command parser. */
	~Command() CXX11_OVERRIDE;

	/** The user modes required to be able to execute this command. */
	unsigned char flags_needed;

	/** Whether the command will not be forwarded by the linking module even if it comes via ENCAP. */
	bool force_manual_route;

	/** The number of seconds worth of penalty that executing this command gives. */
	unsigned int Penalty;

	/** The number of times this command has been executed. */
	unsigned long use_count;

	/** If non-empty then the syntax of the parameter for this command. */
	std::string syntax;

	/** Whether the command can be issued before registering. */
	bool works_before_reg;

	/** Handle the command from a user.
	 * @param user The user who issued the command.
	 * @param parameters The parameters for the command.
	 * @return Returns CMD_FAILURE on failure, CMD_SUCCESS on success, or CMD_INVALID
	 *         if the command was malformed.
	 */
	virtual CmdResult Handle(User* user, const Params& parameters) = 0;

	/** Registers this command with the command parser. */
	void RegisterService() CXX11_OVERRIDE;

	/** Tells the user they did not specify enough parameters.
	 * @param user The user who issued the command.
	 * @param parameters The parameters for the command.
	 */
	virtual void TellNotEnoughParameters(LocalUser* user, const Params& parameters);

	/** Tells the user they need to be registered to execute this command.
	 * @param user The user who issued the command.
	 * @param parameters The parameters for the command.
	 */
	virtual void TellNotRegistered(LocalUser* user, const Params& parameters);
};

class CoreExport SplitCommand : public Command
{
protected:
	/** Initializes a new instance of the SplitCommand class.
	 * @param me The module which created this instance.
	 * @param cmd The name of the command.
	 * @param minpara The minimum number of parameters that the command accepts.
	 * @param maxpara The maximum number of parameters that the command accepts.
	 */
	SplitCommand(Module* me, const std::string& cmd, unsigned int minpara = 0, unsigned int maxpara = 0);

 public:
	/** @copydoc Command::Handle */
	CmdResult Handle(User* user, const Params& parameters) CXX11_OVERRIDE;

	/** Handle the command from a local user.
	 * @param user The user who issued the command.
	 * @param parameters The parameters for the command.
	 * @return Returns CMD_FAILURE on failure, CMD_SUCCESS on success, or CMD_INVALID
	 *         if the command was malformed.
	 */
	virtual CmdResult HandleLocal(LocalUser* user, const Params& parameters);

	/** Handle the command from a remote user.
	 * @param user The user who issued the command.
	 * @param parameters The parameters for the command.
	 * @return Returns CMD_FAILURE on failure, CMD_SUCCESS on success, or CMD_INVALID
	 *         if the command was malformed.
	 */
	virtual CmdResult HandleRemote(RemoteUser* user, const Params& parameters);

	/** Handle the command from a server user.
	 * @param user The user who issued the command.
	 * @param parameters The parameters for the command.
	 * @return Returns CMD_FAILURE on failure, CMD_SUCCESS on success, or CMD_INVALID
	 *         if the command was malformed.
	 */
	virtual CmdResult HandleServer(FakeUser* user, const Params& parameters);
};

/** Shortcut macros for defining translation lists
 */
#define TRANSLATE1(x1)	translation.push_back(x1);
#define TRANSLATE2(x1,x2)  translation.push_back(x1);translation.push_back(x2);
#define TRANSLATE3(x1,x2,x3)  translation.push_back(x1);translation.push_back(x2);translation.push_back(x3);
#define TRANSLATE4(x1,x2,x3,x4)  translation.push_back(x1);translation.push_back(x2);translation.push_back(x3);translation.push_back(x4);
#define TRANSLATE5(x1,x2,x3,x4,x5)  translation.push_back(x1);translation.push_back(x2);translation.push_back(x3);translation.push_back(x4);\
	translation.push_back(x5);
#define TRANSLATE6(x1,x2,x3,x4,x5,x6)  translation.push_back(x1);translation.push_back(x2);translation.push_back(x3);translation.push_back(x4);\
	translation.push_back(x5);translation.push_back(x6);
#define TRANSLATE7(x1,x2,x3,x4,x5,x6,x7)  translation.push_back(x1);translation.push_back(x2);translation.push_back(x3);translation.push_back(x4);\
	translation.push_back(x5);translation.push_back(x6);translation.push_back(x7);
#define TRANSLATE8(x1,x2,x3,x4,x5,x6,x7,x8)  translation.push_back(x1);translation.push_back(x2);translation.push_back(x3);translation.push_back(x4);\
	translation.push_back(x5);translation.push_back(x6);translation.push_back(x7);translation.push_back(x8);
