/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 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 OSGVIEWER_Viewer
#define OSGVIEWER_Viewer 1

#include <osgViewer/GraphicsWindow>
#include <osgViewer/View>
#include <osgGA/EventVisitor>

namespace osgViewer {

/** Viewer holds a single view on to a single scene..*/
class OSGVIEWER_EXPORT Viewer : public osgViewer::View
{
    public:

        Viewer();
        virtual ~Viewer();
        
        /** Get whether at least of one of this viewers windows are realized.*/
        bool isRealized() const;

        /** set up windows and associated threads.*/
        void realize();

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

        void setReferenceTime(double time=0.0);

        osg::FrameStamp* getFrameStamp() { return _frameStamp.get(); }
        const osg::FrameStamp* getFrameStamp() const { return _frameStamp.get(); }


        virtual void setSceneData(osg::Node* node);

        enum ThreadingModel
        {
            SingleThreaded,
            CullDrawThreadPerContext,
            DrawThreadPerContext,
            CullThreadPerCameraDrawThreadPerContext,
            AutomaticSelection
        };
        
        /** Set the threading model the rendering traversals will use.*/
        void setThreadingModel(ThreadingModel threadingModel);
        
        /** Get the threading model the rendering traversals will use.*/
        ThreadingModel getThreadingModel() const { return _threadingModel; }

        /** Set whether the main thread, calling frame(), should be used for the rendering traversals.*/
        void setUseMainThreadForRenderingTraversals(bool flag);
        
        /** Get whether the main thread, calling frame(), should be used for the rendering traversals.*/
        bool getUseMainThreadForRenderingTraversals() const { return _useMainThreadForRenderingTraversal; }

        /** Let the viewer suggest the best threading model for the viewers camera/window setup and the hardware available.*/
        ThreadingModel suggestBestThreadingModel();

        enum BarrierPosition
        {
            BeforeSwapBuffers,
            AfterSwapBuffers
        };
        
        /** Set the position of the end barrier.
          * AfterSwapBuffers will may result is slightly higher framerates, by may
          * lead to inconcistent swapping between different windows.
          * BeforeSwapBuffers may lead to slightly lower framerate, but improve consistency in timing of swap buffers,
          * especially important if you are likely to consistently break frame.*/
        void setEndBarrierPosition(BarrierPosition bp);

        /** Get the end barrier position.*/
        BarrierPosition getEndBarrierPosition() const { return _endBarrierPosition; }

        /** Set the key event that the viewer checks on each frame to see if the viewer's done flag should be set to
          * signal end of viewers main loop.
          * Default value is Escape (osgGA::GUIEVentAdapter::KEY_Escape).
          * Setting to 0 switches off the feature.*/
        void setKeyEventSetsDone(int key) { _keyEventSetsDone = key; }

        /** get the key event that the viewer checks on each frame to see if the viewer's done flag.*/
        int getKeyEventSetsDone() const { return _keyEventSetsDone; }
        
        /** if the flag is true, the viewer set its done flag when a QUIT_APPLICATION is received, false disables this feature */
        void setQuitEventSetsDone(bool flag) { _quitEventSetsDone = flag; }
        
        /** @return true if the viewer respond to the QUIT_APPLICATION-event */
        bool getQuitEventSetsDone() const { return _quitEventSetsDone; }

        /** Execute a main frame loop.
          * Equivialant to while (!viewer.done()) viewer.frame();
          * Also calls realize() if the viewer is not already realized,
          * and installs trackball manipulator if one is not already assigned.
          */
        virtual int run();

        /** Render a complete new frame.
          * Calls advance(), eventTraversal(), updateTraversal(), renderingTraversals(). */
        virtual void frame(double simulationTime=USE_REFERENCE_TIME);

        virtual void advance(double simulationTime=USE_REFERENCE_TIME);

        virtual void eventTraversal();

        virtual void updateTraversal();
        
        virtual void renderingTraversals();
        
        void setCameraWithFocus(osg::Camera* camera) { _cameraWithFocus = camera; }
        osg::Camera* getCameraWithFocus() { return _cameraWithFocus.get(); }
        const osg::Camera* getCameraWithFocus() const { return _cameraWithFocus.get(); }
        
        typedef std::vector<osg::GraphicsContext*> Contexts;
        void getContexts(Contexts& contexts, bool onlyValid=true);
        
        typedef std::vector<osgViewer::GraphicsWindow*> Windows;
        void getWindows(Windows& windows, bool onlyValid=true);
        
        typedef std::vector<osg::Camera*> Cameras;
        void getCameras(Cameras& cameras, bool onlyActive=true);

        typedef std::vector<OpenThreads::Thread*> Threads;
        void getAllThreads(Threads& threads, bool onlyActive=true);

        typedef std::vector<osg::OperationsThread*> OperationsThreads;
        void getOperationsThreads(OperationsThreads& threads, bool onlyActive=true);

        /** Set the graphics operation to call on realization of the viewers graphics windows.*/
        void setRealizeOperation(osg::Operation* op) { _realizeOperation = op; }

        /** Get the graphics operation to call on realization of the viewers graphics windows.*/
        osg::Operation* getRealizeOperation() { return _realizeOperation.get(); }

        /** Set up the threading and processor affinity as per the viewers threading model.*/
        void setUpThreading();      

        /** Stop any threads begin run by viewer.*/
        void stopThreading();

        /** Start any threads required by the viewer.*/
        void startThreading();        

        /** Set up the Operations to render the various viewer cameras on the viewers graphics windows.*/
        void setUpRenderingSupport();

        /** Get the keyboard and mouse usage of this viewer.*/
        virtual void getUsage(osg::ApplicationUsage& usage) const;

    protected:
    
        void checkWindowStatus();
        
        inline void makeCurrent(osg::GraphicsContext* gc)
        {
            if (_currentContext==gc) return;
            
            releaseContext();
            
            if (gc && gc->makeCurrent()) _currentContext = gc;
        }
        
        inline void releaseContext()
        {
            if (_currentContext.valid())
            {
                _currentContext->releaseContext();
                _currentContext = 0;
            }
        }
        
        
        bool _firstFrame;
        
        bool _done;
        int _keyEventSetsDone;
        bool _quitEventSetsDone;
        
        ThreadingModel      _threadingModel;
        bool                _threadsRunning;
        
        bool                _useMainThreadForRenderingTraversal;
        BarrierPosition     _endBarrierPosition;

        osg::ref_ptr<osg::BarrierOperation> _startRenderingBarrier;
        osg::ref_ptr<osg::BarrierOperation> _endRenderingDispatchBarrier;
        osg::ref_ptr<EndOfDynamicDrawBlock> _endDynamicDrawBlock;

        unsigned int _numWindowsOpenAtLastSetUpThreading;
        
        typedef std::list< osg::ref_ptr<osgUtil::SceneView> > SceneViews;
        SceneViews _sceneViews;

        osg::Timer_t                        _startTick;
        osg::ref_ptr<osg::FrameStamp>       _frameStamp;

        osg::observer_ptr<osg::Camera>      _cameraWithFocus;
        
        osg::ref_ptr<osgGA::EventVisitor>   _eventVisitor;
        
        osg::ref_ptr<osg::Operation>        _realizeOperation;
        
        osg::observer_ptr<osg::GraphicsContext> _currentContext;
};


}

#endif