#include <osg/Notify>
#include <osg/MatrixTransform>
#include <osg/ShapeDrawable>
#include <osg/PositionAttitudeTransform>
#include <osg/Geometry>
#include <osg/Texture2D>
#include <osg/Geode>

#include <osgUtil/Optimizer>

#include <osgDB/Registry>
#include <osgDB/ReadFile>

#include <osgProducer/Viewer>


// include the call which creates the shadowed subgraph.
#include "CreateShadowedScene.h"


// for the grid data..
#include "../osghangglide/terrain_coords.h"



osg::AnimationPath* createAnimationPath(const osg::Vec3& center,float radius,double looptime)
{
    // set up the animation path 
    osg::AnimationPath* animationPath = new osg::AnimationPath;
    animationPath->setLoopMode(osg::AnimationPath::LOOP);
    
    int numSamples = 40;
    float yaw = 0.0f;
    float yaw_delta = 2.0f*osg::PI/((float)numSamples-1.0f);
    float roll = osg::inDegrees(30.0f);
    
    double time=0.0f;
    double time_delta = looptime/(double)numSamples;
    for(int i=0;i<numSamples;++i)
    {
        osg::Vec3 position(center+osg::Vec3(sinf(yaw)*radius,cosf(yaw)*radius,0.0f));
        osg::Quat rotation(osg::Quat(roll,osg::Vec3(0.0,1.0,0.0))*osg::Quat(-(yaw+osg::inDegrees(90.0f)),osg::Vec3(0.0,0.0,1.0)));
        
        animationPath->insert(time,osg::AnimationPath::ControlPoint(position,rotation));

        yaw += yaw_delta;
        time += time_delta;

    }
    return animationPath;    
}

osg::Node* createBase(const osg::Vec3& center,float radius)
{

    osg::Geode* geode = new osg::Geode;
    
    // set up the texture of the base.
    osg::StateSet* stateset = new osg::StateSet();
    osg::Image* image = osgDB::readImageFile("Images/lz.rgb");
    if (image)
    {
	osg::Texture2D* texture = new osg::Texture2D;
	texture->setImage(image);
	stateset->setTextureAttributeAndModes(0,texture,osg::StateAttribute::ON);
    }
    
    geode->setStateSet( stateset );


    osg::HeightField* grid = new osg::HeightField;
    grid->allocateGrid(38,39);
    grid->setOrigin(center+osg::Vec3(-radius,-radius,0.0f));
    grid->setXInterval(radius*2.0f/(float)(38-1));
    grid->setYInterval(radius*2.0f/(float)(39-1));
    
    float minHeight = FLT_MAX;
    float maxHeight = -FLT_MAX;


    unsigned int r;
    for(r=0;r<39;++r)
    {
	for(unsigned int c=0;c<38;++c)
	{
            float h = vertex[r+c*39][2];
            if (h>maxHeight) maxHeight=h;
            if (h<minHeight) minHeight=h;
        }
    }
    
    float hieghtScale = radius*0.5f/(maxHeight-minHeight);
    float hieghtOffset = -(minHeight+maxHeight)*0.5f;

    for(r=0;r<39;++r)
    {
	for(unsigned int c=0;c<38;++c)
	{
            float h = vertex[r+c*39][2];
	    grid->setHeight(c,r,(h+hieghtOffset)*hieghtScale);
	}
    }
    
    geode->addDrawable(new osg::ShapeDrawable(grid));
     
    osg::Group* group = new osg::Group;
    group->addChild(geode);
     
    return group;

}

osg::Node* createMovingModel(const osg::Vec3& center, float radius)
{
    float animationLength = 10.0f;

    osg::AnimationPath* animationPath = createAnimationPath(center,radius,animationLength);

    osg::Group* model = new osg::Group;
 
    osg::Node* cessna = osgDB::readNodeFile("cessna.osg");
    if (cessna)
    {
        const osg::BoundingSphere& bs = cessna->getBound();

        float size = radius/bs.radius()*0.3f;
        osg::MatrixTransform* positioned = new osg::MatrixTransform;
        positioned->setDataVariance(osg::Object::STATIC);
        positioned->setMatrix(osg::Matrix::translate(-bs.center())*
                              osg::Matrix::scale(size,size,size)*
                              osg::Matrix::rotate(osg::inDegrees(180.0f),0.0f,0.0f,2.0f));
    
        positioned->addChild(cessna);
    
        osg::MatrixTransform* xform = new osg::MatrixTransform;
        xform->setUpdateCallback(new osg::AnimationPathCallback(animationPath,0.0f,2.0));
        xform->addChild(positioned);

        model->addChild(xform);
    }
    
    return model;
}




osg::Node* createModel()
{
    osg::Vec3 center(0.0f,0.0f,0.0f);
    float radius = 100.0f;
    osg::Vec3 lightPosition(center+osg::Vec3(0.0f,0.0f,radius));

    // the shadower model
    osg::Node* shadower = createMovingModel(center,radius*0.5f);

    // the shadowed model
    osg::Node* shadowed = createBase(center-osg::Vec3(0.0f,0.0f,radius*0.25),radius);

    // combine the models together to create one which has the shadower and the shadowed with the required callback.
    osg::Group* root = createShadowedScene(shadower,shadowed,lightPosition,radius/100.0f,1);

    return root;
}


int main( int argc, char **argv )
{

    // use an ArgumentParser object to manage the program arguments.
    osg::ArgumentParser arguments(&argc,argv);

    // set up the usage document, in case we need to print out how to use this program.
    arguments.getApplicationUsage()->setDescription(arguments.getApplicationName()+" is the example which demonstrates use of pre rendering to texture to create a shadow effect..");
    arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName()+" [options] filename ...");
    arguments.getApplicationUsage()->addCommandLineOption("-h or --help","Display this information");
   
    // construct the viewer.
    osgProducer::Viewer viewer(arguments);

    // set up the value with sensible default event handlers.
    viewer.setUpViewer(osgProducer::Viewer::STANDARD_SETTINGS);

    // get details on keyboard and mouse bindings used by the viewer.
    viewer.getUsage(*arguments.getApplicationUsage());

    // if user request help write it out to cout.
    if (arguments.read("-h") || arguments.read("--help"))
    {
        arguments.getApplicationUsage()->write(std::cout);
        return 1;
    }

    // any option left unread are converted into errors to write out later.
    arguments.reportRemainingOptionsAsUnrecognized();

    // report any errors if they have occured when parsing the program aguments.
    if (arguments.errors())
    {
        arguments.writeErrorMessages(std::cout);
        return 1;
    }
    
    // load the nodes from the commandline arguments.
    osg::Node* model = createModel();
    if (!model)
    {
        return 1;
    }
    
    // comment out optimization over the scene graph right now as it optimizers away the shadow... will look into this..
    //osgUtil::Optimizer optimzer;
    //optimzer.optimize(rootnode);
     
    // add a viewport to the viewer and attach the scene graph.
    viewer.setSceneData( model );
    
    // create the windows and run the threads.
    viewer.realize();

    while( !viewer.done() )
    {
        // wait for all cull and draw threads to complete.
        viewer.sync();

        // update the scene by traversing it with the the update visitor which will
        // call all node update callbacks and animations.
        viewer.update();
         
        // fire off the cull and draw traversals of the scene.
        viewer.frame();
        
    }
    
    // wait for all cull and draw threads to complete before exit.
    viewer.sync();

    return 0;
}