/*  -*-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_SKINNING_H
#define OSGANIMATION_SKINNING_H

#include <iostream>
#include <vector>
#include <map>
#include <string>
#include <algorithm>
#include <osgAnimation/Assert>
#include <osgAnimation/VertexInfluence>
#include <osgAnimation/Bone>
#include <osg/Matrix>
#include <osg/Vec3>
#include <osg/Quat>

namespace osgAnimation 
{


    class TransformVertexFunctor
    {
    public:
        typedef osg::Matrix MatrixType;
        typedef osgAnimation::Bone BoneType;
        typedef Bone::BoneMap BoneMap;

        class BoneWeight 
        {
        public:
            BoneWeight(BoneType* bone, float weight) : _bone(bone), _weight(weight) {}
            const BoneType* getBone() const { return &(*_bone); }
            float getWeight() const { return _weight; }
        protected:
            osg::ref_ptr<BoneType> _bone;
            float _weight;
        };

        typedef std::vector<BoneWeight> BoneWeightList;
        typedef std::vector<int> VertexList;

        class UniqBoneSetVertexSet 
        {
        public:
            BoneWeightList& getBones() { return _bones; }
            VertexList& getVertexes() { return _vertexes; }
            void computeMatrixForVertexSet() 
            {
                if (_bones.empty()) 
                {
                    osg::notify(osg::WARN) << "TransformVertexFunctor::UniqBoneSetVertexSet no bones found" << std::endl;
                    _result = MatrixType::identity();
                    return;
                }
                _result = MatrixType(0, 0, 0, 0,
                                     0, 0, 0, 0,
                                     0, 0, 0, 0,
                                     0, 0, 0, 0);
                int size = _bones.size();
                for (int i = 0; i < size; i++) 
                {
                    const BoneType* bone = _bones[i].getBone();
                    const MatrixType& invBindMatrix = bone->getInvBindMatrixInSkeletonSpace();
                    const MatrixType& matrix = bone->getMatrixInSkeletonSpace();
                    double w = _bones[i].getWeight();
                    _result = _result + ( (invBindMatrix * matrix ) * w);
                }
            }
            const MatrixType& getMatrix() const { return _result;}
        protected:
            BoneWeightList _bones;
            VertexList _vertexes;
            MatrixType _result;
        };


        void init(const BoneMap& map, const osgAnimation::VertexInfluenceSet::UniqVertexSetToBoneSetList& influence)
        {
            _boneSetVertexSet.clear();

            int size = influence.size();
            _boneSetVertexSet.resize(size);
            for (int i = 0; i < size; i++) 
            {
                const osgAnimation::VertexInfluenceSet::UniqVertexSetToBoneSet& inf = influence[i];
                int nbBones = inf.getBones().size();

                for (int b = 0; b < nbBones; b++) 
                {
                    const std::string& bname = inf.getBones()[b].getBoneName();
                    float weight = inf.getBones()[b].getWeight();
                    if (map.find(bname) == map.end()) 
                    {
                        std::cerr << "Warning TransformVertexFunctor Bone " << bname << " not found, skip the influence group " <<bname  << std::endl;
                        continue;
                    }
                    BoneMap::const_iterator it = map.find(bname);
                    if (it == map.end())
                        std::cerr << "Warning TransformVertexFunctor does not find bone " << bname << " in the map" << std::endl;
                    BoneType* bone = it->second.get();
                    _boneSetVertexSet[i].getBones().push_back(BoneWeight(bone, weight));
                }
                _boneSetVertexSet[i].getVertexes() = inf.getVertexes();
            }
        }


        template <class V> void compute(const V* src, V* dst)
        {
            OSGANIMATION_ASSERT(src != dst);
            int size = _boneSetVertexSet.size();
            for (int i = 0; i < size; i++) 
            {
                UniqBoneSetVertexSet& uniq = _boneSetVertexSet[i];
                uniq.computeMatrixForVertexSet();
                const MatrixType& matrix = uniq.getMatrix();

                const VertexList& vertexes = uniq.getVertexes();
                int vertexSize = vertexes.size();
                for (int j = 0; j < vertexSize; j++) 
                {
                    int idx = vertexes[j];
                    dst[idx] = src[idx] * matrix;
                }
            }
        }

        template <class V> void compute(const MatrixType& transform, const MatrixType& invTransform, const V* src, V* dst)
        {
            OSGANIMATION_ASSERT(src != dst);
            int size = _boneSetVertexSet.size();
            for (int i = 0; i < size; i++) 
            {
                UniqBoneSetVertexSet& uniq = _boneSetVertexSet[i];
                uniq.computeMatrixForVertexSet();
                MatrixType matrix =  transform * uniq.getMatrix() * invTransform;

                const VertexList& vertexes = uniq.getVertexes();
                int vertexSize = vertexes.size();
                for (int j = 0; j < vertexSize; j++) 
                {
                    int idx = vertexes[j];
                    dst[idx] = src[idx] * matrix;
                }
            }
        }

    protected:

        std::vector<UniqBoneSetVertexSet> _boneSetVertexSet;
    };
}

#endif