+/**
+ * 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 */
+};
+
+/**
+ * Used to mask off the mode types in the mode handler
+ * array. Used in a simple two instruction hashing function
+ * "(modeletter - 65) OR mask"
+ */
+enum ModeMasks
+{
+ MASK_USER = 128, /* A user mode */
+ MASK_CHANNEL = 0 /* A channel 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
+};
+
+/**
+ * Used by ModeHandler::ModeSet() to return the state of a mode upon a channel or user.
+ * The pair contains an activity flag, true if the mode is set with the given parameter,
+ * and the parameter of the mode (or the parameter provided) in the std::string.
+ */
+typedef std::pair<bool,std::string> ModePair;
+
+/** 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 ¶meter 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 Extensible
+{
+ protected:
+ /**
+ * Creator/owner pointer
+ */
+ InspIRCd* ServerInstance;
+ /**
+ * The mode letter you're implementing.
+ */
+ char mode;
+ /**
+ * Number of parameters when being set
+ */
+ int n_params_on;
+ /**
+ * Number of parameters when being unset
+ */
+ int n_params_off;
+ /**
+ * 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
+ * wether 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;
+ /**
+ * True if the mode requires oper status
+ * to set.
+ */
+ bool oper;
+
+ /** Mode prefix, or 0
+ */
+ char prefix;
+
+ /** Number of items with this mode set on them
+ */
+ unsigned int count;
+
+ /** The prefix char needed on channel to use this mode,
+ * only checked for channel modes
+ */
+ char prefixneeded;
+
+ public:
+ /**
+ * The constructor for ModeHandler initalizes the mode handler.
+ * The constructor of any class you derive from ModeHandler should
+ * probably call this constructor with the parameters set correctly.
+ * @param modeletter The mode letter you wish to handle
+ * @param parameters_on The number of parameters your mode takes when being set. Note that any nonzero value is treated as 1.
+ * @param parameters_off The number of parameters your mode takes when being unset. Note that any nonzero value is treated as 1.
+ * @param listmode Set to true if your mode is a listmode, e.g. it will respond to MODE #channel +modechar with a list of items
+ * @param ModeType Set this to MODETYPE_USER for a usermode, or MODETYPE_CHANNEL for a channelmode.
+ * @param operonly Set this to true if only opers should be allowed to set or unset the mode.
+ * @param mprefix For listmodes where parameters are NICKNAMES which are on the channel (for example, +ohv), you may define a prefix.
+ * When you define a prefix, it can be returned in NAMES, WHO etc if it has the highest value (as returned by GetPrefixRank())
+ * In the core, the only modes to implement prefixes are +ovh (ops, voice, halfop) which define the prefix characters @, % and +
+ * and the rank values OP_VALUE, HALFOP_VALUE and VOICE_VALUE respectively. Any prefixes you define should have unique values proportional
+ * to these three defaults or proportional to another mode in a module you depend on. See src/cmode_o.cpp as an example.
+ */
+ ModeHandler(InspIRCd* Instance, char modeletter, int parameters_on, int parameters_off, bool listmode, ModeType type, bool operonly, char mprefix = 0, char prefixrequired = '%');
+ /**
+ * The default destructor does nothing
+ */
+ virtual ~ModeHandler();
+ /**
+ * Returns true if the mode is a list mode
+ */
+ bool IsListMode();
+ /**
+ * Mode prefix or 0. If this is defined, you should
+ * also implement GetPrefixRank() to return an integer
+ * value for this mode prefix.
+ */
+ char GetPrefix();
+ /** Get number of items with this mode set on them
+ */
+ virtual unsigned int GetCount();
+ /** Adjust usage count returned by GetCount
+ */
+ virtual void ChangeCount(int modifier);
+ /**
+ * 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.
+ */
+ virtual unsigned int GetPrefixRank();
+ /**
+ * Returns the modes type
+ */
+ ModeType GetModeType();
+ /**
+ * Returns true if the mode can only be set/unset by an oper
+ */
+ bool NeedsOper();
+ /**
+ * Returns the number of parameters for the mode. Any non-zero
+ * value should be considered to be equivalent to one.
+ * @param adding If this is true, the number of parameters required to set the mode should be returned, otherwise the number of parameters required to unset the mode shall be returned.
+ * @return The number of parameters the mode expects
+ */
+ int GetNumParams(bool adding);
+ /**
+ * Returns the mode character this handler handles.
+ * @return The mode character
+ */
+ char GetModeChar();
+
+ /**
+ * 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 ¶meter, bool adding, bool servermode = false); /* 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);
+
+ /**
+ * 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 tehy'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 theirs The timestamp of the remote side
+ * @param ours The timestamp of the local side
+ * @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 CheckTimeStamp(time_t theirs, time_t ours, const std::string &their_param, const std::string &our_param, Channel* channel);
+
+ /**
+ * When a remote server needs to bounce a set of modes, it will call this method for every mode
+ * in the mode string to determine if the mode is set or not.
+ * @param source of the mode change, this will be NULL for a server mode
+ * @param dest Target user of the mode change, if this is a user mode
+ * @param channel Target channel of the mode change, if this is a channel mode
+ * @param parameter The parameter given for the mode change, or an empty string
+ * @returns The first value of the pair should be true if the mode is set with the given parameter.
+ * In the case of permissions modes such as channelmode +o, this should return true if the user given
+ * as the parameter has the given privilage on the given channel. The string value of the pair will hold
+ * the current setting for this mode set locally, when the bool is true, or, the parameter given.
+ * This allows the local server to enforce our locally set parameters back to a remote server.
+ */
+ virtual ModePair ModeSet(User* source, User* dest, Channel* channel, const std::string ¶meter);
+
+ /**
+ * When a MODETYPE_USER mode handler is being removed, the server will call this method for every user on the server.
+ * Your mode handler should remove its user mode from the user by sending the appropriate server modes using
+ * InspIRCd::SendMode(). The default implementation of this method can remove simple modes which have no parameters,
+ * and can be used when your mode is of this type, otherwise you must implement a more advanced version of it to remove
+ * your mode properly from each user.
+ * @param user The user which the server wants to remove your mode from
+ */
+ virtual 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.
+ * Your mode handler should remove its user mode from the channel by sending the appropriate server modes using
+ * InspIRCd::SendMode(). The default implementation of this method can remove simple modes which have no parameters,
+ * and can be used when your mode is of this type, otherwise you must implement a more advanced version of it to remove
+ * your mode properly from each channel. Note that in the case of listmodes, you should remove the entire list of items.
+ * @param channel The channel which the server wants to remove your mode from
+ */
+ virtual void RemoveMode(Channel* channel);
+
+ char GetNeededPrefix();
+
+ void SetNeededPrefix(char needsprefix);
+};