/*
 *	DNN - Data News Network
 *
 *	by Stephane Chatty
 *
 *	Copyright 1993-1996
 *	Centre d'Etudes de la Navigation Aerienne (CENA)
 *
 *	Reactions.
 *
 *	$Id$
 *	$CurLog$
 */

#ifndef DnnReaction_H_
#define DnnReaction_H_

#include "ccu/List.h"

class DnnTrigger;
class DnnEvent;

 
class DnnBaseReaction {
friend	class	DnnTrigger;

public:
enum	REL_PRIORITY { isFirstPriority, isNormalPriority, isLastPriority };

protected:
		DnnBaseReaction ();
	CcuListOf <DnnTrigger>	Triggers;
	CcuListOf <DnnTrigger>	Grabbed;

	void	Forget (DnnTrigger&);

public:
virtual		~DnnBaseReaction ();
	void	SubscribeTo (DnnTrigger&, REL_PRIORITY = isNormalPriority);
	void	UnsubscribeTo (DnnTrigger&);
	void	Grab (DnnTrigger&);
	void	Release (DnnTrigger&);
virtual	void	Manage (DnnEvent&);
};

typedef void (*DnnHandlingFunction) (DnnEvent&);

class DnnCallback : public DnnBaseReaction {
protected:
	DnnHandlingFunction	Handler;

public:
		DnnCallback (DnnHandlingFunction);
		~DnnCallback ();
	void	Manage (DnnEvent&);
};

template <class T> class DnnReactionOf : public DnnBaseReaction {
protected:
	T&	Object;
	void	(T::*Reaction)	(DnnEvent&);

public:
		DnnReactionOf (T& o, void (T::*r) (DnnEvent&)) : DnnBaseReaction (), Object (o), Reaction (r)	{}
		~DnnReactionOf ()	{}
	void	Manage (DnnEvent& ev)	{ (Object.*Reaction) (ev); }
};

#define SpecializedReaction(R,S) \
class R : public DnnBaseReaction { \
protected: \
	S&	Body; \
	void	(S::*React)	(DnnEvent&); \
public: \
		R (S& s, void (S::*sc) (DnnEvent&)) : DnnBaseReaction (), Body (s), React (sc)	{} \
		~R ()	{} \
	void	Manage (DnnEvent& ev)	{ (Body.*React) (ev); } \
};

/* Attempt at having reactions that locate the object which should be activated.
    DnnObjectReactionOf should be renamed DnnReactionOf,
    and DnnReactionOf should be renamed DnnBasicReactionOf */

class DnnObjectReaction : public DnnBaseReaction {
protected:
virtual	void*	LocateObject (DnnEvent&) = 0;

public:
		DnnObjectReaction () : DnnBaseReaction ()	{}
		~DnnObjectReaction ()	{}
};

template <class T> class DnnObjectReactionOf : public DnnObjectReaction {
protected:
	void	(T::*Reaction)	(DnnEvent&);
public:
		DnnObjectReactionOf (void (T::*r) (DnnEvent&)) : DnnObjectReaction (), Reaction (r)	{}
		~DnnObjectReactionOf ()	{}
	void	Manage (DnnEvent& ev) { T* o = (T*) LocateObject (ev); (o->*Reaction) (ev); }
};

#if 0
template <class T> class XtvReflexOf : public DnnObjectReactionOf <T> {
protected:
	void*	LocateObject (DnnEvent& ev) { return ((XtvEvent*)&ev)->GetTarget (); }
public:
		XtvReflexOf (void (T::*r) (DnnEvent&)) : DnnObjectReactionOf <T>  (r)	{}
};
#endif

#endif	/* DnnReaction_H_ */