/* OpenSceneGraph example, osgintersection.
*
*  Permission is hereby granted, free of charge, to any person obtaining a copy
*  of this software and associated documentation files (the "Software"), to deal
*  in the Software without restriction, including without limitation the rights
*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
*  copies of the Software, and to permit persons to whom the Software is
*  furnished to do so, subject to the following conditions:
*
*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
*  THE SOFTWARE.
*/

#ifndef FIXIEDDIVISION_H
#define FIXIEDDIVISION_H

  
#include <osgDB/ReadFile>

#include <osg/ArgumentParser>
#include <osg/ApplicationUsage>
#include <osg/Timer>
#include <osg/CoordinateSystemNode>
#include <osg/Notify>
#include <osg/io_utils>
#include <osg/Geometry>
#include <osg/TriangleIndexFunctor>


#include <osgUtil/IntersectionVisitor>
#include <osgUtil/LineSegmentIntersector>
#include <osgUtil/UpdateVisitor>

#include <osgSim/LineOfSight>
#include <osgSim/HeightAboveTerrain>
#include <osgSim/ElevationSlice>

#include <iostream>


namespace fixeddivision
{

typedef int value_type;
typedef std::vector< value_type >   Indices;

// #define VERBOSE_OUTPUT

typedef std::pair< value_type, value_type> KDNode;
typedef std::pair< value_type, value_type> KDLeaf;

struct Triangle
{
    Triangle(unsigned int p1, unsigned int p2, unsigned int p3):
        _p1(p1), _p2(p2), _p3(p3) {}
        
    bool operator < (const Triangle& rhs) const
    {
        if (_p1<rhs._p1) return true;
        if (_p1>rhs._p1) return false;
        if (_p2<rhs._p2) return true;
        if (_p2>rhs._p2) return false;
        return _p3<rhs._p3;
    }
    
    unsigned int _p1;
    unsigned int _p2;
    unsigned int _p3;    
};


class KDPrimitiveLeaf : public osg::Referenced
{
    public:
    
      KDPrimitiveLeaf() {}
      
      Indices _indices;

    protected:
      
      virtual ~KDPrimitiveLeaf() {}    
};

class KDTree : public osg::Shape
{
    public:
    
    
        KDTree() {}
        
        KDTree(const KDTree& rhs, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY):
            Shape(rhs,copyop) {}

        META_Shape(osg, KDTree)
        
    
        typedef std::vector< unsigned int > AxisStack;
        typedef std::vector< KDNode >       KDNodeList;

        typedef std::vector< KDLeaf > KDLeafList;

        /// note, leafNum is negative to distinguish from nodeNum
        int addLeaf(const KDLeaf& leaf) { int num = _kdLeaves.size(); _kdLeaves.push_back(leaf); return -(num+1); }

        int replaceLeaf(int leafNum, const KDLeaf& leaf)
        {
            int num = -leafNum-1; 
            
            if (num>_kdLeaves.size()-1)
            {
                osg::notify(osg::NOTICE)<<"Warning: replaceChild("<<leafNum<<", leaf), num = "<<num<<" _kdLeaves.size()="<<_kdLeaves.size()<<std::endl;
                return leafNum;
            }
            
            _kdLeaves[num] = leaf; return leafNum;
        }

        /// note, leafNum is negative to distinguish from nodeNum
        KDLeaf& getLeaf(int leafNum)
        {
            int num = -leafNum-1;
            if (num<0 || num>_kdLeaves.size()-1)
            {
                osg::notify(osg::NOTICE)<<"Warning: getLeaf("<<leafNum<<", num = "<<num<<") _kdLeaves.size()="<<_kdLeaves.size()<<std::endl;
            }

            return _kdLeaves[num];
        }
        


        /// note, leafNum is negative to distinguish from nodeNum
        int addPrimitiveLeaf(KDPrimitiveLeaf* leaf) { int num = _primitiveList.size(); _primitiveList.push_back(leaf); return -(num+1); }

        int replacePrimitiveLeaf(int leafNum, KDPrimitiveLeaf* leaf)
        {
            int num = -leafNum-1; 
            
            if (num>_primitiveList.size()-1)
            {
                osg::notify(osg::NOTICE)<<"Warning: replaceChild("<<leafNum<<", leaf), num = "<<num<<" _primitiveList.size()="<<_primitiveList.size()<<std::endl;
                return leafNum;
            }
            
            _primitiveList[num] = leaf; return leafNum;
        }


        /// note, leafNum is negative to distinguish from nodeNum
        KDPrimitiveLeaf* getPrimitiveLeaf(int leafNum)
        {
            int num = -leafNum-1;
            if (num<0 || num>_primitiveList.size()-1)
            {
                osg::notify(osg::NOTICE)<<"Warning: getLeaf("<<leafNum<<", num = "<<num<<") _primitiveList.size()="<<_primitiveList.size()<<std::endl;
            }

            return _primitiveList[num].get();
        }

        int addNode(const KDNode& node)
        {
            int num = _kdNodes.size(); 
            _kdNodes.push_back(node); 
            return num;
        }

        /// note, nodeNum is positive to distinguish from leftNum
        KDNode& getNode(int nodeNum)
        {
            if (nodeNum<0 || nodeNum>_kdNodes.size()-1)
            {
                osg::notify(osg::NOTICE)<<"Warning: getNode("<<nodeNum<<") _kdNodes.size()="<<_kdNodes.size()<<std::endl;
            }
            return _kdNodes[nodeNum];
        }


        osg::observer_ptr<osg::Geometry>    _geometry;

        osg::BoundingBox                    _bb;

        AxisStack                           _axisStack;
        KDNodeList                          _kdNodes;
        KDLeafList                          _kdLeaves;

        osg::ref_ptr<osg::Vec3Array>        _vertices;
        Indices                             _vertexIndices;
        
        typedef std::vector< osg::ref_ptr<KDPrimitiveLeaf> > KDPrimitiveList;
        KDPrimitiveList                     _primitiveList;
};

class KDTreeTraverser
{
    public:
    
    
        std::ostream& output(unsigned int level)
        {
            for(unsigned int i=0; i<level; ++i)
            {
                osg::notify(osg::NOTICE)<<"  ";
            }
            return osg::notify(osg::NOTICE);
        }
    

        void traverse(KDTree& tree, KDLeaf& leaf, unsigned int level)
        {
            output(level)<<"leaf("<<level<<") { ";

            unsigned int end = leaf.first+leaf.second;
            for(unsigned int i=leaf.first; i<end; ++i)
            {
                if (i==leaf.first) osg::notify(osg::NOTICE)<<tree._vertexIndices[i];
                else osg::notify(osg::NOTICE)<<", "<<tree._vertexIndices[i];                
            }

            osg::notify(osg::NOTICE)<<"}"<<std::endl;;
            
        }

        void traverse(KDTree& tree, KDPrimitiveLeaf& leaf, unsigned int level)
        {
            output(level)<<"leaf("<<level<<") size()="<<leaf._indices.size()<<"{ ";

            for(unsigned int i=0; i<leaf._indices.size(); ++i)
            {
                if (i==0) osg::notify(osg::NOTICE)<<leaf._indices[i];
                else osg::notify(osg::NOTICE)<<", "<<leaf._indices[i];                
            }

            osg::notify(osg::NOTICE)<<"}"<<std::endl;;
            
        }

        void traverse(KDTree& tree, value_type nodeIndex, unsigned int level)
        {
            output(level)<<"traverse("<<nodeIndex<<", "<< level<<") { "<<std::endl;
            
            if (nodeIndex>=0)
            {        
                KDNode& node = tree._kdNodes[nodeIndex];
                if (node.first) traverse(tree,node.first,level+1);
                else output(level+1)<<"empty left child()"<<std::endl;
                
                if (node.second) traverse(tree,node.second,level+1);
                else output(level+1)<<"empty right child()"<<std::endl;
            }
            else 
            {
                value_type leafIndex = -nodeIndex-1;
                
                if (leafIndex<tree._primitiveList.size())
                {
                    KDPrimitiveLeaf& leaf = *(tree._primitiveList[leafIndex]);
                    traverse(tree, leaf, level);
                }
                else
                {
                    KDLeaf& leaf = tree._kdLeaves[leafIndex];
                    traverse(tree, leaf, level);
                }

            }

            output(level)<<"}"<<std::endl;;
        }


        void traverse(KDTree& tree)
        {
            osg::notify(osg::NOTICE)<<"traverse(tree)"<<std::endl;
            if (!tree._kdNodes.empty()) 
            {
                traverse(tree,0,0);
            }
            else if (!tree._kdLeaves.empty())
            {
                traverse(tree, tree._kdLeaves.front(), 0);
            }
        }
    
};

class KDTreeBuilder : public osg::NodeVisitor
{
    public:
    
        KDTreeBuilder():
            osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN),
            _maxNumLevels(16),
            _targetNumVerticesPerLeaf(8),
            _targetNumIndicesPerLeaf(15),
            _numVerticesProcessed(0),
            _processTriangles(true)
        {            
        }
    
    
        void apply(osg::Geode& geode)
        {
            for(unsigned int i=0; i<geode.getNumDrawables(); ++i)
            {
                osg::Geometry* geom = geode.getDrawable(i)->asGeometry();
                if (geom)
                {
                    geom->setShape(createKDTree(geom));
                }   
            }
        }
    
        KDTree* createKDTree(osg::Geometry* geometry);
        
        void computeDivisions(KDTree& kdTree);
        
        int divideTriangles(KDTree& kdTree, osg::BoundingBox& bb, int nodeIndex, unsigned int level);
        int dividePoints(KDTree& kdTree, osg::BoundingBox& bb, int nodeIndex, unsigned int level);

        unsigned int _maxNumLevels;
        unsigned int _targetNumVerticesPerLeaf;
        unsigned int _targetNumIndicesPerLeaf;
        
        unsigned int _numVerticesProcessed;
        bool         _processTriangles;
        
        inline void disposeKDPrimitiveLeaf(KDPrimitiveLeaf* leaf)
        {
            leaf->_indices.clear();
            _leafRecycleList.push_back(leaf);
        }
        
        inline KDPrimitiveLeaf* createKDPrimitiveLeaf()
        {
            if (_leafRecycleList.empty()) return new KDPrimitiveLeaf;
            osg::ref_ptr<KDPrimitiveLeaf> leaf = _leafRecycleList.back();
            _leafRecycleList.pop_back();
            return leaf.release();
        }
        
        typedef std::list< osg::ref_ptr<KDPrimitiveLeaf> > LeafRecyleList;
        LeafRecyleList _leafRecycleList;

};


}

#endif