[user/henk/code/inspircd.git] / include / mode.h

/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2013-2016 Attila Molnar <attilamolnar@hush.com>
 *   Copyright (C) 2012-2013, 2017-2021 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2012 Robby <robby@chatbelgie.be>
 *   Copyright (C) 2009 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) 2006-2008, 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

#include "ctables.h"
#include "modechange.h"

/**
 * Holds the values for different type of modes
 * that can exist, USER or CHANNEL type.
 */
enum ModeType
{
        /** User mode */
        MODETYPE_USER = 0,
        /** Channel mode */
        MODETYPE_CHANNEL = 1
};

/**
 * Holds mode actions - modes can be allowed or denied.
 */
enum ModeAction
{
        MODEACTION_DENY = 0, /* Drop the mode change, AND a parameter if its a parameterized mode */
        MODEACTION_ALLOW = 1 /* Allow the mode */
};

/**
 * These fixed values can be used to proportionally compare module-defined prefixes to known values.
 * For example, if your module queries a Channel, and is told that user 'joebloggs' has the prefix
 * '$', and you dont know what $ means, then you can compare it to these three values to determine
 * its worth against them. For example if '$' had a value of 15000, you would know it is of higher
 * status than voice, but lower status than halfop.
 * No two modes should have equal prefix values.
 */
enum PrefixModeValue
{
        /* +v */
        VOICE_VALUE     =       10000,
        /* +h */
        HALFOP_VALUE    =       20000,
        /* +o */
        OP_VALUE        =       30000
};

enum ParamSpec
{
        /** No parameters */
        PARAM_NONE,
        /** Parameter required on mode setting only */
        PARAM_SETONLY,
        /** Parameter always required */
        PARAM_ALWAYS
};

class PrefixMode;
class ListModeBase;
class ParamModeBase;

/** Each mode is implemented by ONE ModeHandler class.
 * You must derive ModeHandler and add the child class to
 * the list of modes handled by the ircd, using
 * ModeParser::AddMode. When the mode you implement is
 * set by a user, the virtual function OnModeChange is
 * called. If you specify a value greater than 0 for
 * parameters_on or parameters_off, then when the mode is
 * set or unset respectively, std::string &parameter will
 * contain the parameter given by the user, else it will
 * contain an empty string. You may alter this parameter
 * string, and if you alter it to an empty string, and your
 * mode is expected to have a parameter, then this is
 * equivalent to returning MODEACTION_DENY.
 */
class CoreExport ModeHandler : public ServiceProvider
{
 public:
        typedef size_t Id;

        enum Class
        {
                MC_PREFIX,
                MC_LIST,
                MC_PARAM,
                MC_OTHER
        };

 private:
        /** The opaque id of this mode assigned by the mode parser
         */
        Id modeid;

 protected:
        /** What kind of parameters does the mode take?
         */
        ParamSpec parameters_taken;

        /**
         * The mode letter you're implementing.
         */
        char mode;

        /**
         * True if the mode requires oper status
         * to set.
         */
        bool oper;

        /**
         * Mode is a 'list' mode. The behaviour
         * of your mode is now set entirely within
         * the class as of the 1.1 api, rather than
         * inside the mode parser as in the 1.0 api,
         * so the only use of this value (along with
         * IsListMode()) is for the core to determine
         * whether your module can produce 'lists' or not
         * (e.g. banlists, etc)
         */
        bool list;

        /**
         * The mode type, either MODETYPE_USER or
         * MODETYPE_CHANNEL.
         */
        ModeType m_type;

        /** The object type of this mode handler
         */
        const Class type_id;

        /** The prefix rank required to set this mode on channels. */
        unsigned int ranktoset;

        /** The prefix rank required to unset this mode on channels. */
        unsigned int ranktounset;

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

 public:
        /**
         * The constructor for ModeHandler initializes the mode handler.
         * The constructor of any class you derive from ModeHandler should
         * probably call this constructor with the parameters set correctly.
         * @param me The module which created this mode
         * @param name A one-word name for the mode
         * @param modeletter The mode letter you wish to handle
         * @param params Parameters taken by the mode
         * @param type Type of the mode (MODETYPE_USER or MODETYPE_CHANNEL)
         * @param mclass The object type of this mode handler, one of ModeHandler::Class
         */
        ModeHandler(Module* me, const std::string& name, char modeletter, ParamSpec params, ModeType type, Class mclass = MC_OTHER);
        CullResult cull() CXX11_OVERRIDE;
        virtual ~ModeHandler();

        /** Register this object in the ModeParser
         */
        void RegisterService() CXX11_OVERRIDE;

        /**
         * Returns true if the mode is a list mode
         */
        bool IsListMode() const { return list; }

        /**
         * Check whether this mode is a prefix mode
         * @return non-NULL if this mode is a prefix mode, NULL otherwise
         */
        PrefixMode* IsPrefixMode();

        /**
         * Check whether this mode is a prefix mode
         * @return non-NULL if this mode is a prefix mode, NULL otherwise
         */
        const PrefixMode* IsPrefixMode() const;

        /**
         * Check whether this mode handler inherits from ListModeBase
         * @return non-NULL if this mode handler inherits from ListModeBase, NULL otherwise
         */
        ListModeBase* IsListModeBase();

        /**
         * Check whether this mode handler inherits from ListModeBase
         * @return non-NULL if this mode handler inherits from ListModeBase, NULL otherwise
         */
        const ListModeBase* IsListModeBase() const;

        /**
         * Check whether this mode handler inherits from ParamModeBase
         * @return non-NULL if this mode handler inherits from ParamModeBase, NULL otherwise
         */
        ParamModeBase* IsParameterMode();

        /**
         * Check whether this mode handler inherits from ParamModeBase
         * @return non-NULL if this mode handler inherits from ParamModeBase, NULL otherwise
         */
        const ParamModeBase* IsParameterMode() const;

        /**
         * Returns the mode's type
         */
        inline ModeType GetModeType() const { return m_type; }
        /**
         * Returns true if the mode can only be set/unset by an oper
         */
        inline bool NeedsOper() const { return oper; }
        /**
         * Check if the mode needs a parameter for adding or removing
         * @param adding True to check if the mode needs a parameter when setting, false to check if the mode needs a parameter when unsetting
         * @return True if the mode needs a parameter for the specified action, false if it doesn't
         */
        bool NeedsParam(bool adding) const;
        /**
         * Returns the mode character this handler handles.
         * @return The mode character
         */
        char GetModeChar() const { return mode; }

        /** Return the id of this mode which is used in User::modes and
         * Channel::modes as the index to determine whether a mode is set.
         */
        Id GetId() const { return modeid; }

        /** For user modes, return the current parameter, if any
         */
        virtual std::string GetUserParameter(const User* user) const;

        /**
         * Called when a channel mode change access check for your mode occurs.
         * @param source Contains the user setting the mode.
         * @param channel contains the destination channel the modes are being set on.
         * @param parameter The parameter for your mode. This is modifiable.
         * @param adding This value is true when the mode is being set, or false when it is being unset.
         * @return allow, deny, or passthru to check against the required level
         */
        virtual ModResult AccessCheck(User* source, Channel* channel, std::string &parameter, bool adding);

        /**
         * Called when a mode change for your mode occurs.
         * @param source Contains the user setting the mode.
         * @param dest For usermodes, contains the destination user the mode is being set on. For channelmodes, this is an undefined value.
         * @param channel For channel modes, contains the destination channel the modes are being set on. For usermodes, this is an undefined value.
         * @param parameter The parameter for your mode, if you indicated that your mode requires a parameter when being set or unset. Note that
         * if you alter this value, the new value becomes the one displayed and send out to the network, also, if you set this to an empty string
         * but you specified your mode REQUIRES a parameter, this is equivalent to returning MODEACTION_DENY and will prevent the mode from being
         * displayed.
         * @param adding This value is true when the mode is being set, or false when it is being unset.
         * @return MODEACTION_ALLOW to allow the mode, or MODEACTION_DENY to prevent the mode, also see the description of 'parameter'.
         */
        virtual ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string &parameter, bool adding); /* Can change the mode parameter as its a ref */

        /**
         * If your mode is a listmode, then this method will be called for displaying an item list, e.g. on MODE \#channel +modechar
         * without any parameter or other modes in the command.
         * @param user The user issuing the command
         * @param channel The channel they're requesting an item list of (e.g. a banlist, or an exception list etc)
         */
        virtual void DisplayList(User* user, Channel* channel);

        /** In the event that the mode should be given a parameter, and no parameter was provided, this method is called.
         * This allows you to give special information to the user, or handle this any way you like.
         * @param user The user issuing the mode change
         * @param dest For user mode changes, the target of the mode. For channel mode changes, NULL.
         * @param channel For channel mode changes, the target of the mode. For user mode changes, NULL.
         */
        virtual void OnParameterMissing(User* user, User* dest, Channel* channel);

        /** Called when a user attempts to set a mode and the parameter is invalid.
         * @param user The user issuing the mode change
         * @param targetchannel Either the channel target or NULL if changing a user mode.
         * @param targetuser Either the user target or NULL if changing a channel mode.
         * @param parameter The invalid parameter.
         */
        virtual void OnParameterInvalid(User* user, Channel* targetchannel, User* targetuser, const std::string& parameter);


        /**
         * If your mode is a listmode, this method will be called to display an empty list (just the end of list numeric)
         * @param user The user issuing the command
         * @param channel The channel they're requesting an item list of (e.g. a banlist, or an exception list etc)
         */
        virtual void DisplayEmptyList(User* user, Channel* channel);

        /**
         * If your mode needs special action during a server sync to determine which side wins when comparing timestamps,
         * override this function and use it to return true or false. The default implementation just returns true if
         * theirs < ours. This will only be called for non-listmodes with parameters, when adding the mode and where
         * theirs == ours (therefore the default implementation will always return false).
         * @param their_param Their parameter if the mode has a parameter
         * @param our_param Our parameter if the mode has a parameter
         * @param channel The channel we are checking against
         * @return True if the other side wins the merge, false if we win the merge for this mode.
         */
        virtual bool ResolveModeConflict(std::string &their_param, const std::string &our_param, Channel* channel);

        /**
         * When a MODETYPE_USER mode handler is being removed, the core will call this method for every user on the server.
         * The usermode will be removed using the appropriate server mode using InspIRCd::SendMode().
         * @param user The user which the server wants to remove your mode from
         */
        void RemoveMode(User* user);

        /**
         * When a MODETYPE_CHANNEL mode handler is being removed, the server will call this method for every channel on the server.
         * The mode handler has to populate the given modestacker with mode changes that remove the mode from the channel.
         * The default implementation of this method can remove all kinds of channel modes except listmodes.
         * In the case of listmodes, the entire list of items must be added to the modestacker (which is handled by ListModeBase,
         * so if you inherit from it or your mode can be removed by the default implementation then you do not have to implement
         * this function).
         * @param channel The channel which the server wants to remove your mode from
         * @param changelist Mode change list to populate with the removal of this mode
         */
        virtual void RemoveMode(Channel* channel, Modes::ChangeList& changelist);

        /** Retrieves the level required to modify this mode.
         * @param adding Whether the mode is being added or removed.
         */
        inline unsigned int GetLevelRequired(bool adding) const
        {
                return adding ? ranktoset : ranktounset;
        }

        /** Retrieves the syntax of the parameter for this mode. */
        const std::string& GetSyntax() const { return syntax; }

        friend class ModeParser;
};

/**
 * Prefix modes are channel modes that grant a specific rank to members having prefix mode set.
 * They require a parameter when setting and unsetting; the parameter is always a member of the channel.
 * A prefix mode may be set on any number of members on a channel, but for a given member a given prefix
 * mode is either set or not set, in other words members cannot have the same prefix mode set more than once.
 *
 * A rank of a member is defined as the rank given by the 'strongest' prefix mode that member has.
 * Other parts of the IRCd use this rank to determine whether a channel action is allowable for a user or not.
 * The rank of a prefix mode is constant, i.e. the same rank value is given to all users having that prefix mode set.
 *
 * Note that it is possible that the same action requires a different rank on a different channel;
 * for example changing the topic on a channel having +t set requires a rank that is >= than the rank of a halfop,
 * but there is no such restriction when +t isn't set.
 */
class CoreExport PrefixMode : public ModeHandler
{
 protected:
        /** The prefix character granted by this mode. '@' for op, '+' for voice, etc.
         * If 0, this mode does not have a visible prefix character.
         */
        char prefix;

        /** The prefix rank of this mode, used to compare prefix
         * modes
         */
        unsigned int prefixrank;

        /** Whether a client with this prefix can remove it from themself. */
        bool selfremove;

 public:
        /**
         * Constructor
         * @param Creator The module creating this mode
         * @param Name The user-friendly one word name of the prefix mode, e.g.: "op", "voice"
         * @param ModeLetter The mode letter of this mode
         * @param Rank Rank given by this prefix mode, see explanation above
         * @param PrefixChar Prefix character, or 0 if the mode has no prefix character
         */
        PrefixMode(Module* Creator, const std::string& Name, char ModeLetter, unsigned int Rank = 0, char PrefixChar = 0);

        /**
         * Called when a channel mode change access check for your mode occurs.
         * @param source Contains the user setting the mode.
         * @param channel contains the destination channel the modes are being set on.
         * @param parameter The parameter for your mode. This is modifiable.
         * @param adding This value is true when the mode is being set, or false when it is being unset.
         * @return allow, deny, or passthru to check against the required level
         */
        ModResult AccessCheck(User* source, Channel* channel, std::string &parameter, bool adding) CXX11_OVERRIDE;

        /**
         * Handles setting and unsetting the prefix mode.
         * Finds the given member of the given channel, if it's not found an error message is sent to 'source'
         * and MODEACTION_DENY is returned. Otherwise the mode change is attempted.
         * @param source Source of the mode change, an error message is sent to this user if the target is not found
         * @param dest Unused
         * @param channel The channel the mode change is happening on
         * @param param The nickname or uuid of the target user
         * @param adding True when the mode is being set, false when it is being unset
         * @return MODEACTION_ALLOW if the change happened, MODEACTION_DENY if no change happened
         * The latter occurs either when the member cannot be found or when the member already has this prefix set
         * (when setting) or doesn't have this prefix set (when unsetting).
         */
        ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string& param, bool adding) CXX11_OVERRIDE;

        /**
         * Updates the configuration of this prefix.
         * @param rank The prefix rank of this mode.
         * @param setrank The prefix rank required to set this mode on channels.
         * @param unsetrank The prefix rank required to set this unmode on channels.
         * @param selfrm Whether a client with this prefix can remove it from themself.
         */
        void Update(unsigned int rank, unsigned int setrank, unsigned int unsetrank, bool selfrm);

        /**
         * Removes this prefix mode from all users on the given channel
         * @param channel The channel which the server wants to remove your mode from
         * @param changelist Mode change list to populate with the removal of this mode
         */
        void RemoveMode(Channel* channel, Modes::ChangeList& changelist) CXX11_OVERRIDE;


        /**
        * Determines whether a user with this prefix mode can remove it.
        */
        bool CanSelfRemove() const { return selfremove; }

        /**
         * Mode prefix or 0. If this is defined, you should
         * also implement GetPrefixRank() to return an integer
         * value for this mode prefix.
         */
        char GetPrefix() const { return prefix; }

        /**
         * Get the 'value' of this modes prefix.
         * determines which to display when there are multiple.
         * The mode with the highest value is ranked first. See the
         * PrefixModeValue enum and Channel::GetPrefixValue() for
         * more information.
         */
        unsigned int GetPrefixRank() const { return prefixrank; }
};

/** A prebuilt mode handler which handles a simple user mode, e.g. no parameters, usable by any user, with no extra
 * behaviour to the mode beyond the basic setting and unsetting of the mode, not allowing the mode to be set if it
 * is already set and not allowing it to be unset if it is already unset.
 * An example of a simple user mode is user mode +w.
 */
class CoreExport SimpleUserModeHandler : public ModeHandler
{
 public:
        SimpleUserModeHandler(Module* Creator, const std::string& Name, char modeletter, bool operonly = false)
                : ModeHandler(Creator, Name, modeletter, PARAM_NONE, MODETYPE_USER)
        {
                oper = operonly;
        }

        ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string& parameter, bool adding) CXX11_OVERRIDE;
};

/** A prebuilt mode handler which handles a simple channel mode, e.g. no parameters, usable by any user, with no extra
 * behaviour to the mode beyond the basic setting and unsetting of the mode, not allowing the mode to be set if it
 * is already set and not allowing it to be unset if it is already unset.
 * An example of a simple channel mode is channel mode +s.
 */
class CoreExport SimpleChannelModeHandler : public ModeHandler
{
 public:
        SimpleChannelModeHandler(Module* Creator, const std::string& Name, char modeletter, bool operonly = false)
                : ModeHandler(Creator, Name, modeletter, PARAM_NONE, MODETYPE_CHANNEL)
        {
                oper = operonly;
        }

        ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string& parameter, bool adding) CXX11_OVERRIDE;
};

/**
 * The ModeWatcher class can be used to alter the behaviour of a mode implemented
 * by the core or by another module. To use ModeWatcher, derive a class from it,
 * and attach it to the mode using Server::AddModeWatcher and Server::DelModeWatcher.
 * A ModeWatcher will be called both before and after the mode change.
 */
class CoreExport ModeWatcher : public classbase
{
 private:
        /**
         * The mode name this class is watching
         */
        const std::string mode;

        /**
         * The mode type being watched (user or channel)
         */
        ModeType m_type;

 public:
        ModuleRef creator;
        /**
         * The constructor initializes the mode and the mode type
         */
        ModeWatcher(Module* creator, const std::string& modename, ModeType type);
        /**
         * The default destructor does nothing.
         */
        virtual ~ModeWatcher();

        /**
         * Get the mode name being watched
         * @return The mode name being watched
         */
        const std::string& GetModeName() const { return mode; }

        /**
         * Get the mode type being watched
         * @return The mode type being watched (user or channel)
         */
        ModeType GetModeType() const { return m_type; }

        /**
         * Before the mode character is processed by its handler, this method will be called.
         * @param source The sender of the mode
         * @param dest The target user for the mode, if you are watching a user mode
         * @param channel The target channel for the mode, if you are watching a channel mode
         * @param parameter The parameter of the mode, if the mode is supposed to have a parameter.
         * If you alter the parameter you are given, the mode handler will see your atered version
         * when it handles the mode.
         * @param adding True if the mode is being added and false if it is being removed
         * @return True to allow the mode change to go ahead, false to abort it. If you abort the
         * change, the mode handler (and ModeWatcher::AfterMode()) will never see the mode change.
         */
        virtual bool BeforeMode(User* source, User* dest, Channel* channel, std::string& parameter, bool adding);
        /**
         * After the mode character has been processed by the ModeHandler, this method will be called.
         * @param source The sender of the mode
         * @param dest The target user for the mode, if you are watching a user mode
         * @param channel The target channel for the mode, if you are watching a channel mode
         * @param parameter The parameter of the mode, if the mode is supposed to have a parameter.
         * You cannot alter the parameter here, as the mode handler has already processed it.
         * @param adding True if the mode is being added and false if it is being removed
         */
        virtual void AfterMode(User* source, User* dest, Channel* channel, const std::string& parameter, bool adding);
};

/** The mode parser handles routing of modes and handling of mode strings.
 * It marshalls, controls and maintains both ModeWatcher and ModeHandler classes,
 * parses client to server MODE strings for user and channel modes, and performs
 * processing for the 004 mode list numeric, amongst other things.
 */
class CoreExport ModeParser : public fakederef<ModeParser>
{
 public:
        /** The maximum number of modes which can be created. */
        static const ModeHandler::Id MODEID_MAX = 64;

        /** The maximum length of a mode parameter. */
        static const size_t MODE_PARAM_MAX = 250;

        /** Type of the container that maps mode names to ModeHandlers
         */
        typedef TR1NS::unordered_map<std::string, ModeHandler*, irc::insensitive, irc::StrHashComp> ModeHandlerMap;

 private:
        /** Type of the container that maps mode names to ModeWatchers
         */
        typedef insp::flat_multimap<std::string, ModeWatcher*> ModeWatcherMap;

        /** Last item in the ModeType enum
         */
        static const unsigned int MODETYPE_LAST = 2;

        /** Mode handlers for each mode, to access a handler subtract
         * 65 from the ascii value of the mode letter.
         * The upper bit of the value indicates if its a usermode
         * or a channel mode, so we have 256 of them not 64.
         */
        ModeHandler* modehandlers[MODETYPE_LAST][128];

        /** An array of mode handlers indexed by the mode id
         */
        ModeHandler* modehandlersbyid[MODETYPE_LAST][MODEID_MAX];

        /** A map of mode handlers keyed by their name
         */
        ModeHandlerMap modehandlersbyname[MODETYPE_LAST];

        /** Lists of mode handlers by type
         */
        struct
        {
                /** List of mode handlers that inherit from ListModeBase
                 */
                std::vector<ListModeBase*> list;

                /** List of mode handlers that inherit from PrefixMode
                 */
                std::vector<PrefixMode*> prefix;
        } mhlist;

        /** Mode watcher classes
         */
        ModeWatcherMap modewatchermap;

        /** Last processed mode change
         */
        Modes::ChangeList LastChangeList;

        /**
         * Attempts to apply a mode change to a user or channel
         */
        ModeAction TryMode(User* user, User* targu, Channel* targc, Modes::Change& mcitem, bool SkipACL);

        /** Allocates an unused id for the given mode type, throws a ModuleException if out of ids.
         * @param mt The type of the mode to allocate the id for
         * @return The id
         */
        ModeHandler::Id AllocateModeId(ModeType mt);

 public:
        typedef std::vector<ListModeBase*> ListModeList;
        typedef std::vector<PrefixMode*> PrefixModeList;

        typedef unsigned int ModeProcessFlag;
        enum ModeProcessFlags
        {
                /** If only this flag is specified, the mode change will be global
                 * and parameter modes will have their parameters explicitly set
                 * (not merged). This is the default.
                 */
                MODE_NONE = 0,

                /** If this flag is set then the parameters of non-listmodes will be
                 * merged according to their conflict resolution rules.
                 * Does not affect user modes, channel modes without a parameter and
                 * listmodes.
                 */
                MODE_MERGE = 1,

                /** If this flag is set then the linking module will ignore the mode change
                 * and not send it to other servers. The mode change will be processed
                 * locally and sent to local user(s) as usual.
                 */
                MODE_LOCALONLY = 2,

                /** If this flag is set then the mode change will be subject to access checks.
                 * For more information see the documentation of the PrefixMode class,
                 * ModeHandler::ranktoset and ModeHandler::AccessCheck().
                 * Modules may explicitly allow a mode change regardless of this flag by returning
                 * MOD_RES_ALLOW from the OnPreMode hook. Only affects channel mode changes.
                 */
                MODE_CHECKACCESS = 4
        };

        ModeParser();
        ~ModeParser();

        static bool IsModeChar(char chr);

        /** Tidy a banmask. This makes a banmask 'acceptable' if fields are left out.
         * E.g.
         *
         * nick -> nick!*@*
         *
         * nick!ident -> nick!ident@*
         *
         * host.name -> *!*\@host.name
         *
         * ident@host.name -> *!ident\@host.name
         *
         * This method can be used on both IPV4 and IPV6 user masks.
         */
        static void CleanMask(std::string &mask);

        /** Gets the last mode change to be processed. */
        const Modes::ChangeList& GetLastChangeList() const { return LastChangeList; }

        /** Add a mode to the mode parser.
         * Throws a ModuleException if the mode cannot be added.
         */
        void AddMode(ModeHandler* mh);

        /** Delete a mode from the mode parser.
         * When a mode is deleted, the mode handler will be called
         * for every user (if it is a user mode) or for every  channel
         * (if it is a channel mode) to unset the mode on all objects.
         * This prevents modes staying in the system which no longer exist.
         * @param mh The mode handler to remove
         * @return True if the mode was successfully removed.
         */
        bool DelMode(ModeHandler* mh);

        /** Add a mode watcher.
         * A mode watcher is triggered before and after a mode handler is
         * triggered. See the documentation of class ModeWatcher for more
         * information.
         * @param mw The ModeWatcher you want to add
         */
        void AddModeWatcher(ModeWatcher* mw);

        /** Delete a mode watcher.
         * A mode watcher is triggered before and after a mode handler is
         * triggered. See the documentation of class ModeWatcher for more
         * information.
         * @param mw The ModeWatcher you want to delete
         * @return True if the ModeWatcher was deleted correctly
         */
        bool DelModeWatcher(ModeWatcher* mw);

        /** Process a list of mode changes entirely. If the mode changes do not fit into one MODE line
         * then multiple MODE lines are generated.
         * @param user The source of the mode change, can be a server user.
         * @param targetchannel Channel to apply the mode change on. NULL if changing modes on a channel.
         * @param targetuser User to apply the mode change on. NULL if changing modes on a user.
         * @param changelist Modes to change in form of a Modes::ChangeList.
         * @param flags Optional flags controlling how the mode change is processed,
         * defaults to MODE_NONE.
         */
        void Process(User* user, Channel* targetchannel, User* targetuser, Modes::ChangeList& changelist, ModeProcessFlag flags = MODE_NONE);

        /** Process a single MODE line's worth of mode changes, taking max modes and line length limits
         * into consideration. Return value indicates how many modes were processed.
         * @param user The source of the mode change, can be a server user.
         * @param targetchannel Channel to apply the mode change on. NULL if changing modes on a channel.
         * @param targetuser User to apply the mode change on. NULL if changing modes on a user.
         * @param changelist Modes to change in form of a Modes::ChangeList. May not process
         * the entire list due to MODE line length and max modes limitations.
         * @param flags Optional flags controlling how the mode change is processed,
         * defaults to MODE_NONE.
         * @param beginindex Index of the first element in changelist to process. Mode changes before
         * the element with this index are ignored.
         * @return Number of mode changes processed from changelist.
         */
        unsigned int ProcessSingle(User* user, Channel* targetchannel, User* targetuser, Modes::ChangeList& changelist, ModeProcessFlag flags = MODE_NONE, unsigned int beginindex = 0);

        /** Turn a list of parameters compatible with the format of the MODE command into
         * Modes::ChangeList form. All modes are processed, regardless of max modes. Unknown modes
         * are skipped.
         * @param user The source of the mode change, can be a server user. Error numerics are sent to
         * this user.
         * @param type MODETYPE_USER if this is a user mode change or MODETYPE_CHANNEL if this
         * is a channel mode change.
         * @param parameters List of strings describing the mode change to convert to a ChangeList.
         * Must be using the same format as the parameters of a MODE command.
         * @param changelist ChangeList object to populate.
         * @param beginindex Index of the first element that is part of the MODE list in the parameters
         * container. Defaults to 1.
         * @param endindex Index of the first element that is not part of the MODE list. By default,
         * the entire container is considered part of the MODE list.
         */
        void ModeParamsToChangeList(User* user, ModeType type, const std::vector<std::string>& parameters, Modes::ChangeList& changelist, unsigned int beginindex = 1, unsigned int endindex = UINT_MAX);

        /** Find the mode handler for a given mode name and type.
         * @param modename The mode name to search for.
         * @param mt Type of mode to search for, user or channel.
         * @return A pointer to a ModeHandler class, or NULL of there isn't a handler for the given mode name.
         */
        ModeHandler* FindMode(const std::string& modename, ModeType mt);

        /** Find the mode handler for a given mode and type.
         * @param modeletter mode letter to search for
         * @param mt type of mode to search for, user or channel
         * @returns a pointer to a ModeHandler class, or NULL of there isn't a handler for the given mode
         */
        ModeHandler* FindMode(unsigned const char modeletter, ModeType mt);

        /** Find the mode handler for the given prefix mode
         * @param modeletter The mode letter to search for
         * @return A pointer to the PrefixMode or NULL if the mode wasn't found or it isn't a prefix mode
         */
        PrefixMode* FindPrefixMode(unsigned char modeletter);

        /** Find a mode handler by its prefix.
         * If there is no mode handler with the given prefix, NULL will be returned.
         * @param pfxletter The prefix to find, e.g. '@'
         * @return The mode handler which handles this prefix, or NULL if there is none.
         */
        PrefixMode* FindPrefix(unsigned const char pfxletter);

        /** Generates a list of modes, comma separated by type:
         *  1; Listmodes EXCEPT those with a prefix
         *  2; Modes that take a param when adding or removing
         *  3; Modes that only take a param when adding
         *  4; Modes that dont take a param
         */
        std::string GiveModeList(ModeType mt);

        /** This returns the PREFIX=(ohv)@%+ section of the 005 numeric, or
         * just the "@%+" part if the parameter false
         */
        std::string BuildPrefixes(bool lettersAndModes = true);

        /** Get a list of all mode handlers that inherit from ListModeBase
         * @return A list containing ListModeBase modes
         */
        const ListModeList& GetListModes() const { return mhlist.list; }

        /** Get a list of all prefix modes
         * @return A list containing all prefix modes
         */
        const PrefixModeList& GetPrefixModes() const { return mhlist.prefix; }

        /** Get a mode name -> ModeHandler* map containing all modes of the given type
         * @param mt Type of modes to return, MODETYPE_USER or MODETYPE_CHANNEL
         * @return A map of mode handlers of the given type
         */
        const ModeHandlerMap& GetModes(ModeType mt) const { return modehandlersbyname[mt]; }

        /** Show the list of a list mode to a user. Modules can deny the listing.
         * @param user User to show the list to.
         * @param chan Channel to show the list of.
         * @param mh List mode to show the list of.
         */
        void ShowListModeList(User* user, Channel* chan, ModeHandler* mh);
};

inline PrefixMode* ModeHandler::IsPrefixMode()
{
        return (this->type_id == MC_PREFIX ? static_cast<PrefixMode*>(this) : NULL);
}

inline const PrefixMode* ModeHandler::IsPrefixMode() const
{
        return (this->type_id == MC_PREFIX ? static_cast<const PrefixMode*>(this) : NULL);
}

inline ListModeBase* ModeHandler::IsListModeBase()
{
        return (this->type_id == MC_LIST ? reinterpret_cast<ListModeBase*>(this) : NULL);
}

inline const ListModeBase* ModeHandler::IsListModeBase() const
{
        return (this->type_id == MC_LIST ? reinterpret_cast<const ListModeBase*>(this) : NULL);
}

inline ParamModeBase* ModeHandler::IsParameterMode()
{
        return (this->type_id == MC_PARAM ? reinterpret_cast<ParamModeBase*>(this) : NULL);
}

inline const ParamModeBase* ModeHandler::IsParameterMode() const
{
        return (this->type_id == MC_PARAM ? reinterpret_cast<const ParamModeBase*>(this) : NULL);
}