/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2005 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * This library 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 
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSGGA_EVENTQUEUE
#define OSGGA_EVENTQUEUE 1

#include <osgGA/GUIEventAdapter>

#include <osg/ref_ptr>
#include <osg/Timer>

#include <OpenThreads/Mutex>
#include <list>

namespace osgGA {

/**
 * EventQueue implementation for collecting and adapting windowing events 
 */
class OSGGA_EXPORT EventQueue : public osg::Referenced
{
    public:

        EventQueue(GUIEventAdapter::MouseYOrientation mouseYOrientation=GUIEventAdapter::Y_INCREASING_DOWNWARDS);

        typedef std::list< osg::ref_ptr<GUIEventAdapter> > Events;
                
        /** Set events.*/
        void setEvents(Events& events);

        /** Take the entire event queue leaving the EventQueue' event queue empty.*/
        bool takeEvents(Events& events);

        /** Take a copy the entire event queue leaving the EventQueue' event queue intact.*/
        bool copyEvents(Events& events) const;

        /** Add events to end of event queue.*/
        void appendEvents(Events& events);

        /** Add an event to the end of the event queue.*/
        void addEvent(GUIEventAdapter* event);


        /** method for adapting window resize event, placing this event on the back of the event queue. */
        void windowResize(float Xmin, float Ymin, float Xmax, float Ymax);

        /** method for adapting mouse scroll wheel events, placing this event on the back of the event queue. */
        void mouseScroll(GUIEventAdapter::ScrollingMotion sm);

        /** method for updating in response to a mouse warp. Note, just moves the mouse position without creating a new event for it.*/
        void mouseWarp(float x, float y);

        /** method for adapting mouse motion events whilst mouse buttons are pressed, placing this event on the back of the event queue.*/
        void mouseMotion(float x, float y);

        /** method for adapting mouse button pressed events, placing this event on the back of the event queue.*/
        void mouseButtonPress(float x, float y, unsigned int button);
        
        /** method for adapting mouse button release events, placing this event on the back of the event queue.*/
        void mouseButtonRelease(float x, float y, unsigned int button);

        /** method for adapting keyboard press events.*/
        void keyPress(GUIEventAdapter::KeySymbol key);

        /** method for adapting keyboard press events.*/
        void keyRelease(GUIEventAdapter::KeySymbol key);

        /** method for adapting frame events.*/
        void frame(double t);
        

        void setStartTick(osg::Timer_t tick) { _startTick = tick; }
        osg::Timer_t getStartTick() const { return _startTick; }

        double getTime() const { return osg::Timer::instance()->delta_s(_startTick, osg::Timer::instance()->tick()); }

        /** convinience method for create an event ready to fill in.  Clones the getCurrentEventState() to produce a up to date event state. */
        GUIEventAdapter* createEvent();
        
        GUIEventAdapter* getCurrentEventState() { return _accumulateEventState.get(); }
        const GUIEventAdapter* getCurrentEventState() const { return _accumulateEventState.get(); }

    protected:

        virtual ~EventQueue();

        /** Prevent unwanted copy operator.*/
        EventQueue& operator = (const EventQueue&) { return *this; }
        
        osg::ref_ptr<GUIEventAdapter>   _accumulateEventState;

        osg::Timer_t                _startTick;
        mutable OpenThreads::Mutex  _eventQueueMutex;
        Events                      _eventQueue;
    
};

}

#endif