/*  -*-c++-*- 
 *  Copyright (C) 2008 Cedric Pinson <mornifle@plopbyte.net>
 *
 * 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 OSGANIMATION_TIMELINE_H
#define OSGANIMATION_TIMELINE_H

#include <osgAnimation/Export>
#include <osg/Object>
#include <map>
#include <vector>
#include <osg/Notify>
#include <osg/Group>
#include <osgAnimation/Animation>
#include <osgAnimation/AnimationManagerBase>

namespace osgAnimation
{

    class Action : public virtual osg::Object
    {
    public:

        class Callback : public virtual osg::Object
        {
        public:
            Callback(){}
            Callback(const Callback& nc,const osg::CopyOp&) {}

            META_Object(osgAnimation,Callback);
        
            virtual void operator()(Action* action) {}
            void addNestedCallback(Callback* callback) 
            { 
                if (_nested.valid())
                    _nested->addNestedCallback(callback);
                else
                    _nested = callback;
            }

        protected:
            osg::ref_ptr<Callback> _nested;
        };


        typedef std::map<unsigned int, osg::ref_ptr<Callback> > FrameCallback;

        META_Object(osgAnimation, Action);
        Action()
        {
            _numberFrame = 25;
            _fps = 25;
            _speed = 1.0;
            _loop = 1;
        }
        Action(const Action& nc,const osg::CopyOp&) {}

        void setCallback(double when, Callback* callback)
        {
            setCallback(static_cast<unsigned int>(floor(when*_fps)), callback);
        }

        void setCallback(unsigned int frame, Callback* callback)
        {
            if (_framesCallback[frame].valid())
                _framesCallback[frame]->addNestedCallback(callback);
            else
                _framesCallback[frame] = callback;
        }
        Callback* getCallback(unsigned int frame)
        {
            if (_framesCallback.find(frame) == _framesCallback.end())
                return 0;
            return _framesCallback[frame].get();
        }

        void setNumFrames(unsigned int numFrames) { _numberFrame = numFrames;}
        void setDuration(double duration) { _numberFrame = static_cast<unsigned int>(floor(duration * _fps)); }

        unsigned int getNumFrames() const { return _numberFrame;}
        double getDuration() const { return _numberFrame * 1.0 / _fps; }

        // 0 means infini else it's the number of loop
        virtual void setLoop(int nb) { _loop = nb; }
        virtual unsigned int getLoop() const { return _loop;}

        // get the number of loop, the frame relative to loop.
        // return true if in range, and false if out of range.
        bool evaluateFrame(unsigned int frame, unsigned int& resultframe, unsigned int& nbloop )
        {
            nbloop = frame / getNumFrames();
            resultframe = frame;

            if (frame > getNumFrames()-1)
            {
                if (!getLoop())
                    resultframe = frame % getNumFrames();
                else
                {
                    if (nbloop >= getLoop())
                        return false;
                    else
                        resultframe = frame % getNumFrames();
                }
            }
            return true;
        }

        virtual void evaluate(unsigned int frame)
        {
            unsigned int frameInAction;
            unsigned int loopDone;
            if (!evaluateFrame(frame, frameInAction, loopDone))
                osg::notify(osg::DEBUG_INFO) << getName() << " Action frame " << frameInAction  << " finished" << std::endl;
            else
                osg::notify(osg::DEBUG_INFO) << getName() << " Action frame " << frame  << " relative to loop " << frameInAction  << " no loop " << loopDone<< std::endl;
        }

        virtual void evaluateCallback(unsigned int frame)
        {
            unsigned int frameInAction;
            unsigned int loopDone;
            if (!evaluateFrame(frame, frameInAction, loopDone))
                return;

            frame = frameInAction;
            if (_framesCallback.find(frame) != _framesCallback.end())
            {
                std::cout << getName() << " evaluate callback " << _framesCallback[frame]->getName() << " at " << frame << std::endl;
                (*_framesCallback[frame])(this);
            }
        }

    protected:
        FrameCallback _framesCallback;

        double _speed;
        unsigned int _fps;
        unsigned int _numberFrame;
        unsigned int _loop;

        enum State
        {
            Play,
            Stop
        };
        
        State _state;
    };


    class Timeline : public virtual osg::Object
    {
    protected:
        typedef std::pair<unsigned int, osg::ref_ptr<Action> > FrameAction;
        typedef std::vector<FrameAction> ActionList;
        typedef std::map<int, ActionList> ActionLayers;
        enum State
        {
            Play,
            Stop
        };
        

        ActionLayers _actions;
        double _lastUpdate;
        double _speed;
        unsigned int _currentFrame;
        unsigned int _fps;
        unsigned int _numberFrame;
        unsigned int _previousFrameEvaluated;
        bool _loop;
        bool _initFirstFrame;

        State _state;

        // to manage pending operation
        bool _evaluating;

        struct Command
        {
            Command():_priority(0) {}
            Command(int priority, const FrameAction& action) : _priority(priority), _action(action) {}
            int _priority;
            FrameAction _action;
        };

        typedef std::vector<Command> CommandList;
        CommandList _addActionOperations;
        ActionList _removeActionOperations;

        void setEvaluating(bool state) { _evaluating = state;}
        void processPendingOperation()
        {
            // process all pending add action operation
            while( !_addActionOperations.empty())
            {
                internalAddAction(_addActionOperations.back()._priority, _addActionOperations.back()._action);
                _addActionOperations.pop_back();
            }

            // process all pending remove action operation
            while( !_removeActionOperations.empty())
            {
                internalRemoveAction(_removeActionOperations.back().second.get());
                _removeActionOperations.pop_back();
            }
        }

        void internalRemoveAction(Action* action)
        {
            for (ActionLayers::iterator it = _actions.begin(); it != _actions.end(); it++)
            {
                ActionList& fa = it->second;
                for (unsigned int i = 0; i < fa.size(); i++)
                    if (fa[i].second.get() == action)
                    {
                        fa.erase(fa.begin() + i);
                        return;
                    }
            }
        }
        void internalAddAction(int priority, const FrameAction& ftl)
        {
            _actions[priority].push_back(ftl);
        }
        
    public:

        META_Object(osgAnimation, Timeline);

        Timeline();
        Timeline(const Timeline& nc,const osg::CopyOp& op = osg::CopyOp::SHALLOW_COPY);
        State getStatus() const { return _state; }
        const ActionList& getActionLayer(int i)
        {
            return _actions[i];
        }
        unsigned int getCurrentFrame() const { return _currentFrame;}
        double getCurrentTime() const { return _currentFrame * 1.0 / _fps;}

        void play() { _state = Play; }
        void gotoFrame(unsigned int frame) { _currentFrame = frame; }
        void stop() { _state = Stop; }
        bool getEvaluating() const { return _evaluating;}

        bool isActive(Action* activeAction)
        {
            // update from high priority to low priority
            for( ActionLayers::iterator iterAnim = _actions.begin(); iterAnim != _actions.end(); ++iterAnim )
            {
                // update all animation
                ActionList& list = iterAnim->second;
                for (unsigned int i = 0; i < list.size(); i++)
                {
                    Action* action = list[i].second.get();
                    if (action == activeAction) 
                    {
                        unsigned int firstFrame = list[i].first;
                        // check if current frame of timeline hit an action interval
                        if (_currentFrame >= firstFrame && 
                            _currentFrame < (firstFrame + action->getNumFrames()) )
                            return true;
                    }
                }
            }
            return false;
        }

        void removeAction(Action* action)
        {
            if (getEvaluating())
                _removeActionOperations.push_back(FrameAction(0, action));
            else
                internalRemoveAction(action);
        }

        virtual void addActionAt(unsigned int frame, Action* action, int priority = 0)
        {
            if (getEvaluating())
                _addActionOperations.push_back(Command(priority,FrameAction(frame, action)));
            else
                internalAddAction(priority, FrameAction(frame, action));
        }
        virtual void addActionAt(double t, Action* action, int priority = 0)
        {
            unsigned int frame = static_cast<unsigned int>(floor(t * _fps));
            addActionAt(frame, action, priority);
        }

        virtual void evaluate(unsigned int frame)
        {
            setEvaluating(true);
            osg::notify(osg::DEBUG_INFO) << getName() << " evaluate frame " << _currentFrame << std::endl;

            // update from high priority to low priority
            for( ActionLayers::reverse_iterator iterAnim = _actions.rbegin(); iterAnim != _actions.rend(); ++iterAnim )
            {
                // update all animation
                ActionList& list = iterAnim->second;
                for (unsigned int i = 0; i < list.size(); i++)
                {
                    unsigned int firstFrame = list[i].first;
                    Action* action = list[i].second.get();
                    // check if current frame of timeline hit an action interval
                    if (frame >= firstFrame && 
                        frame < (firstFrame + action->getNumFrames()) )
                        action->evaluate(frame - firstFrame);
                }
            }
            setEvaluating(false);

            // evaluate callback after updating all animation
            evaluateCallback(frame);
            _previousFrameEvaluated = frame;
        }

        virtual void evaluateCallback(unsigned int frame)
        {
            // update from high priority to low priority
            for( ActionLayers::reverse_iterator iterAnim = _actions.rbegin(); iterAnim != _actions.rend(); ++iterAnim )
            {
                // update all animation
                ActionList& list = iterAnim->second;
                for (unsigned int i = 0; i < list.size(); i++)
                {
                    unsigned int firstFrame = list[i].first;
                    Action* action = list[i].second.get();
                    // check if current frame of timeline hit an action interval
                    if (frame >= firstFrame && 
                        frame < (firstFrame + action->getNumFrames()) )
                        action->evaluateCallback(frame - firstFrame);
                }
            }
            processPendingOperation();
        }

        virtual void update(double simulationTime)
        {
            // first time we call update we generate one frame
            if (!_initFirstFrame)
            {
                _lastUpdate = simulationTime;
                _initFirstFrame = true;
                evaluate(_currentFrame);
            }

            // find the number of frame pass since the last update
            double delta = (simulationTime - _lastUpdate);
            double nbframes = delta * _fps * _speed;
            unsigned int nb = static_cast<unsigned int>(floor(nbframes));

            for (unsigned int i = 0; i < nb; i++)
            {
                if (_state == Play)
                    _currentFrame++;
                evaluate(_currentFrame);
            }
            if (nb)
            {
                _lastUpdate += ((double)nb) / _fps;
            }
        }
    };



    // blend in from 0 to weight in duration
    class BlendIn : public Action
    {
        double _weight;
        osg::ref_ptr<Animation> _animation;

    public:
        BlendIn(Animation* animation, double duration, double weight)
        {
            _animation = animation;
            _weight = weight;
            float d = duration * _fps;
            setNumFrames(static_cast<unsigned int>(floor(d)) + 1);
            setName("BlendIn");
        }
        double getWeight() const { return _weight;}
        virtual void evaluate(unsigned int frame)
        {
            Action::evaluate(frame);
            // frame + 1 because the start is 0 and we want to start the blend in at the first
            // frame.
            double ratio = ( (frame+1) * 1.0 / (getNumFrames()) );
            double w = _weight;
            if (frame < getNumFrames() -1 ) // the last frame we set the target weight the user asked
                w = _weight * ratio;
            _animation->setWeight(w);
        }
    };

    // blend in from 0 to weight in duration
    class BlendOut : public Action
    {
        double _weight;
        osg::ref_ptr<Animation> _animation;
    public:
        BlendOut(Animation* animation, double duration)
        {
            _animation = animation;
            float d = duration * _fps;
            setNumFrames(static_cast<unsigned int>(floor(d) + 1));
            _weight = 1.0;
            setName("BlendOut");
        }
        double getWeight() const { return _weight;}
        virtual void evaluate(unsigned int frame)
        {
            Action::evaluate(frame);
            // frame + 1 because the start is 0 and we want to start the blend in at the first
            // frame.
            double ratio = ( (frame+1) * 1.0 / (getNumFrames()) );
            double w = 0.0;
            if (frame < getNumFrames() -1 ) // the last frame we set the target weight the user asked
                w = _weight * (1.0-ratio);
            _animation->setWeight(w);
        }
    };


    class ActionAnimation : public Action
    {
    public:
        ActionAnimation(Animation* animation) : _animation(animation) 
        {
            setDuration(animation->getDuration()); 
            setName(animation->getName());
        }
        virtual void evaluate(unsigned int frame) 
        {
            Action::evaluate(frame);
            _animation->update(frame * 1.0/_fps); 
        }
        Animation* getAnimation() { return _animation.get(); }
    protected:
        osg::ref_ptr<Animation> _animation;
    };


    // encapsulate animation with blend in blend out for classic usage
    class StripAnimation : public Action
    {
    protected:
        typedef std::pair<unsigned int, osg::ref_ptr<Action> > FrameAction;

    public:
        StripAnimation(Animation* animation, double blendInDuration, double blendOutDuration, double blendInWeightTarget = 1.0  )
        {
            _blendIn = new BlendIn(animation, blendInDuration, blendInWeightTarget);
            _animation = new ActionAnimation(animation);
            unsigned int start = static_cast<unsigned int>(floor((_animation->getDuration() - blendOutDuration) * _fps));
            _blendOut = FrameAction(start, new BlendOut(animation, blendOutDuration));
            setName(animation->getName() + "_Strip");
            _blendIn->setName(_animation->getName() + "_" + _blendIn->getName());
            _blendOut.second->setName(_animation->getName() + "_" + _blendOut.second->getName());
            setDuration(animation->getDuration());
        }

        ActionAnimation* getActionAnimation() { return _animation.get(); }
        BlendIn* getBlendIn() { return _blendIn.get(); }
        BlendOut* getBlendOut() { return dynamic_cast<BlendOut*>(_blendOut.second.get()); }
        const ActionAnimation* getActionAnimation() const { return _animation.get(); }
        const BlendIn* getBlendIn() const { return _blendIn.get(); }
        const BlendOut* getBlendOut() const { return dynamic_cast<BlendOut*>(_blendOut.second.get()); }

        unsigned int getLoop() const { return _animation->getLoop(); }
        void setLoop(unsigned int loop)
        {
            _animation->setLoop(loop);
            if (!loop)
                setDuration(-1);
            else
                setDuration(loop * _animation->getDuration());

            // duration changed re evaluate the blendout duration
            unsigned int start = static_cast<unsigned int>(floor((getDuration() - _blendOut.second->getDuration()) * _fps));
            _blendOut = FrameAction(start, _blendOut.second);
        }

        virtual void evaluate(unsigned int frame)
        {
            if (frame > getNumFrames() - 1)
                return;

            Action::evaluate(frame);
            if (frame < _blendIn->getNumFrames())
                _blendIn->evaluate(frame);
            if (frame >= _blendOut.first)
                _blendOut.second->evaluate(frame - _blendOut.first);
            _animation->evaluate(frame);
        }

    protected:
        osg::ref_ptr<BlendIn> _blendIn;
        FrameAction _blendOut;
        osg::ref_ptr<ActionAnimation> _animation;
    };


    class RunAction : public Action::Callback
    {
    protected:
        osg::ref_ptr<Timeline> _tm;
        osg::ref_ptr<Action> _action;
        
    public:
        RunAction(Timeline* tm, Action* a) : _tm(tm), _action(a) {}
        virtual void operator()(Action* action)
        {
            _tm->addActionAt(_tm->getCurrentFrame(), _action.get()); // warning we are trsversing the vector
        }
    };



}

#endif