// -*-c++-*- osgWidget - Code by: Jeremy Moles (cubicool) 2007-2008
// $Id: EventInterface 64 2008-06-30 21:32:00Z cubicool $

#ifndef OSGWIDGET_EVENT_INTERFACE
#define OSGWIDGET_EVENT_INTERFACE

#include <list>
#include <osg/ref_ptr>
#include <osg/Referenced>

#include <osgWidget/Export>

namespace osgWidget {

class WindowManager;
class Window;
class Widget;

enum EVENT_TYPE {
	EVENT_NONE          = 0x0000,
	EVENT_FOCUS         = 0x0001,
	EVENT_UNFOCUS       = 0x0002,
	EVENT_MOUSE_ENTER   = 0x0004,
	EVENT_MOUSE_OVER    = 0x0008,
	EVENT_MOUSE_LEAVE   = 0x0010,
	EVENT_MOUSE_DRAG    = 0x0020,
	EVENT_MOUSE_PUSH    = 0x0040,
	EVENT_MOUSE_RELEASE = 0x0080,
	EVENT_MOUSE_SCROLL  = 0x0100,
	EVENT_KEY_DOWN      = 0x0200,
	EVENT_KEY_UP        = 0x0400,
	EVENT_ALL           = 0xFFFF
};

// Helpful wrapper around using the raw types, since it often doesn't make sense to
// use some without the others.
enum EVENT_MASK {
	EVENT_MASK_FOCUS        = EVENT_FOCUS | EVENT_UNFOCUS,
	EVENT_MASK_MOUSE_MOVE   = EVENT_MOUSE_ENTER | EVENT_MOUSE_OVER | EVENT_MOUSE_LEAVE,
	EVENT_MASK_MOUSE_CLICK  = EVENT_MOUSE_PUSH | EVENT_MOUSE_RELEASE,
	EVENT_MASK_MOUSE_DRAG   = EVENT_MASK_MOUSE_MOVE | EVENT_MASK_MOUSE_CLICK | EVENT_MOUSE_DRAG,
	EVENT_MASK_KEY          = EVENT_KEY_UP | EVENT_KEY_DOWN
};

class OSGWIDGET_EXPORT Event {
	friend class WindowManager;
	friend class Window;

	WindowManager* _wm;
	Window*        _window;
	Widget*        _widget;
	void*          _data;

public:
	EVENT_TYPE type;
	double     x;
	double     y;
	int        key;
	int        keyMask;

	Event(WindowManager* wm, EVENT_TYPE _type = EVENT_NONE):
	_wm     (wm),
	_window (0),
	_widget (0),
	_data   (0),
	type    (_type),
	x       (0.0f),
	y       (0.0f),
	key     (-1),
	keyMask (-1) {
	}

	Event& makeType(EVENT_TYPE _type) {
		if(_type != EVENT_NONE) type = _type;

		return *this;
	}

	Event& makeMouse(double _x, double _y, EVENT_TYPE _type = EVENT_NONE) {
		x = _x;
		y = _y;

		if(_type != EVENT_NONE) type = _type;

		return *this;
	}

	Event& makeKey(int _key, int _keyMask, EVENT_TYPE _type = EVENT_NONE) {
		key     = _key;
		keyMask = _keyMask;

		if(_type != EVENT_NONE) type = _type;

		return *this;
	}

	WindowManager* getWindowManager() {
		return _wm;
	}

	const WindowManager* getWindowManager() const {
		return _wm;
	}

	Window* getWindow() {
		return _window;
	}

	const Window* getWindow() const {
		return _window;
	}

	Widget* getWidget() {
		return _widget;
	}

	const Widget* getWidget() const {
		return _widget;
	}

	void* getData() {
		return _data;
	}

	const void* getData() const {
		return _data;
	}

	void setData(void* data) {
		_data = data;
	}
};

// The Callback interface was inspired by the CEGUI project:
//
// 	http://www.cegui.org.uk/wiki/index.php/Main_Page
//
// It's a great little way to cleanly implement callbacks for events, although
// I did change the names a bit to make them more appropriate for OSG. MANY THANKS
// to the CEGUI project!

// The CallbackInterface, which the highest-level functor keeps a pointer to.
struct CallbackInterface: public osg::Referenced {
	virtual ~CallbackInterface() {
	}

	virtual bool operator()(Event&) = 0;
};

// The object that facilitates a class method as a callback.
template<typename T>
class ObjectCallback: public CallbackInterface {
public:
	typedef bool (T::*ObjectCallbackType)(Event&);

private:
	ObjectCallbackType _callback;
	T*                 _object;

public:
	ObjectCallback(ObjectCallbackType callback, T* obj):
	_callback (callback),
	_object   (obj) {
	}

	virtual bool operator()(Event& ev) {
		return (_object->*_callback)(ev);
	}
};

// The object that facilitates general functions as callbacks.
template<typename T>
class FunctionCallback: public CallbackInterface {
	T* _callback;

public:
	FunctionCallback(T* callback):
	_callback(callback) {
	}

	virtual bool operator()(Event& ev) {
		return (*_callback)(ev);
	}
};

// The highlevel functor.
class OSGWIDGET_EXPORT Callback {
	EVENT_TYPE _type;
	void*      _data;

	// We use a ref_ptr here so that we don't have to worry about memory.
	osg::ref_ptr<CallbackInterface> _callback;

public:
	// Creates a Callback that is bound to a member function.
	template<typename T>
	Callback(bool (T::*function)(Event&), T* obj, EVENT_TYPE type, void* data=0):
	_type     (type),
	_data     (data),
	_callback (new ObjectCallback<T>(function, obj)) {
	}

	// Creates a Callback that is bound to a functor pointer.
	template<typename T>
	Callback(T* functor, EVENT_TYPE type, void* data=0):
	_type     (type),
	_data     (data),
	_callback (new FunctionCallback<T>(functor)) {
	}

	bool operator()(Event& ev) {
		return (*_callback)(ev);
	}

	EVENT_TYPE getType() const {
		return _type;
	}

	void* getData() {
		return _data;
	}

	const void* getData() const {
		return _data;
	}
};


class OSGWIDGET_EXPORT EventInterface {
private:
	typedef std::list<Callback> CallbackList;

	unsigned int _eventMask;
	CallbackList _callbacks;

public:
	EventInterface():
	_eventMask(EVENT_NONE) {
	}

	EventInterface(const EventInterface& ei):
	_eventMask (ei._eventMask),
	_callbacks (ei._callbacks) {
	}

	virtual ~EventInterface() {
	}

	// These functions take as their final argument the WindowManager which issued the
	// request. This is sometimes useful to get information about key state, etc.
	
	// Notify the EventInterface object that is has been focused or unfocused; since
	// this isn't always bound to a mouse event (i.e., if you want to be able to use
	// the TAB key to focus), we need seperate events here.
	virtual bool focus   (WindowManager*) { return false; }
	virtual bool unfocus (WindowManager*) { return false; }
	
	// Mouse events, pretty self-explanatory.
	virtual bool mouseEnter   (double, double, WindowManager*) { return false; }
	virtual bool mouseOver    (double, double, WindowManager*) { return false; }
	virtual bool mouseLeave   (double, double, WindowManager*) { return false; }
	virtual bool mouseDrag    (double, double, WindowManager*) { return false; }
	virtual bool mousePush    (double, double, WindowManager*) { return false; }
	virtual bool mouseRelease (double, double, WindowManager*) { return false; }
	virtual bool mouseScroll  (double, double, WindowManager*) { return false; }

	// These functions pass the osgGA::GUIEventAdapter::KeySymbol and KeyModMask and,
	// as above, the WindowManager.
	virtual bool keyDown (int, int, WindowManager*) { return false; }
	virtual bool keyUp   (int, int, WindowManager*) { return false; }

	void setEventMask(unsigned int mask) {
		_eventMask = mask;
	}

	void addEventMask(unsigned int mask) {
		_eventMask |= mask;
	}

	void removeEventMask(unsigned int mask) {
		_eventMask ^= mask;
	}

	unsigned int getEventMask() const {
		return _eventMask;
	}

	void addCallback(const Callback& cb) {
		_callbacks.push_back(cb);
	}

	bool callCallbacks(Event& ev) {
		if(ev.type == EVENT_NONE || !(_eventMask & ev.type)) return false;

		for(CallbackList::iterator i = _callbacks.begin(); i != _callbacks.end(); i++) {
			// This is the OLD method; testing a new method below.
			// if(i->getType() == ev.type && (*i)(ev)) return true;

			if(i->getType() == ev.type) {
				ev.setData(i->getData());

				if((*i)(ev)) return true;
			}
		}

		return false;
	}

	bool callMethodAndCallbacks(Event& ev) {
		if(ev.type == EVENT_NONE || !(_eventMask & ev.type)) return false;
		
		bool handled = false;

		if(ev.type == EVENT_FOCUS) handled = focus(ev.getWindowManager());

		else if(ev.type == EVENT_UNFOCUS) handled = unfocus(ev.getWindowManager());
		
		else if(ev.type == EVENT_MOUSE_ENTER)
			handled = mouseEnter(ev.x, ev.y, ev.getWindowManager())
		;
		
		else if(ev.type == EVENT_MOUSE_OVER)
			handled = mouseOver(ev.x, ev.y, ev.getWindowManager())
		;
		
		else if(ev.type == EVENT_MOUSE_LEAVE)
			handled = mouseLeave(ev.x, ev.y, ev.getWindowManager())
		;
		
		else if(ev.type == EVENT_MOUSE_DRAG)
			handled = mouseDrag(ev.x, ev.y, ev.getWindowManager())
		;
		
		else if(ev.type == EVENT_MOUSE_PUSH)
			handled = mousePush(ev.x, ev.y, ev.getWindowManager())
		;
		
		else if(ev.type == EVENT_MOUSE_RELEASE)
			handled = mouseRelease(ev.x, ev.y, ev.getWindowManager())
		;
		
		else if(ev.type == EVENT_MOUSE_SCROLL)
			handled = mouseScroll(ev.x, ev.y, ev.getWindowManager())
		;
		
		else if(ev.type == EVENT_KEY_DOWN)
			handled = keyDown(ev.key, ev.keyMask, ev.getWindowManager())
		;
		
		else if(ev.type == EVENT_KEY_UP)
			handled = keyUp(ev.key, ev.keyMask, ev.getWindowManager())
		;

		else return false;

		return callCallbacks(ev) || handled;
	}

	bool canFocus   () const { return (_eventMask & EVENT_FOCUS) != 0; }
	bool canUnfocus () const { return (_eventMask & EVENT_UNFOCUS) != 0; }

	bool canMouseEnter   () const { return (_eventMask & EVENT_MOUSE_ENTER) != 0; }
	bool canMouseOver    () const { return (_eventMask & EVENT_MOUSE_OVER) != 0; }
	bool canMouseLeave   () const { return (_eventMask & EVENT_MOUSE_LEAVE) != 0; }
	bool canMouseDrag    () const { return (_eventMask & EVENT_MOUSE_DRAG) != 0; }
	bool canMousePush    () const { return (_eventMask & EVENT_MOUSE_PUSH) != 0; }
	bool canMouseRelease () const { return (_eventMask & EVENT_MOUSE_RELEASE) != 0; }
	bool canMouseScroll  () const { return (_eventMask & EVENT_MOUSE_SCROLL) != 0; }

	bool canKeyDown () const { return (_eventMask & EVENT_KEY_DOWN) != 0; }
	bool canKeyUp   () const { return (_eventMask & EVENT_KEY_UP) != 0; }
};

}

#endif