/*  -*-c++-*-
 *  Copyright (C) 2009 Cedric Pinson <cedric.pinson@plopbyte.net>
 *  Copyright (C) 2017 Julien Valentin <mp3butcher@hotmail.com>
 *
 * 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_RIGTRANSFORM_SOFTWARE
#define OSGANIMATION_RIGTRANSFORM_SOFTWARE 1

#include <osgAnimation/Export>
#include <osgAnimation/RigTransform>
#include <osgAnimation/Bone>
#include <osgAnimation/VertexInfluence>
#include <osg/observer_ptr>

namespace osgAnimation
{

    class RigGeometry;

    /// This class manage format for software skinning
    class OSGANIMATION_EXPORT RigTransformSoftware : public RigTransform
    {
    public:
        RigTransformSoftware();
        RigTransformSoftware(const RigTransformSoftware& rts,const osg::CopyOp& copyop);

        META_Object(osgAnimation,RigTransformSoftware)

        virtual void operator()(RigGeometry&);
        //to call when a skeleton is reacheable from the rig to prepare technic data
        virtual bool prepareData(RigGeometry&);

        class BonePtrWeight: std::pair< osg::observer_ptr< Bone >, float>
        {
        public:
            BonePtrWeight(Bone*bone, float weight) :std::pair< osg::observer_ptr< Bone >, float>(bone,weight) {}
            BonePtrWeight(const BonePtrWeight &bw2) : std::pair< osg::observer_ptr< Bone >, float>(bw2.first.get(),bw2.getWeight()) {}

            inline const Bone * getBonePtr() const {return first.get();}
            inline void setBonePtr(Bone*b){first=b;}
            inline const float & getWeight() const {return second;}
            inline void setWeight(float b) {second=b;}
            inline bool operator<(const BonePtrWeight &b1) const{
                    if (second > b1.second)return true;
                    if (second < b1.second)return false;
                    return (first.get() > b1.first.get());
            }
        };
        typedef std::vector<BonePtrWeight>  BonePtrWeightList;

        /// map a set of boneinfluence to a list of vertex indices sharing this set
        class VertexGroup
        {
        public:
            inline BonePtrWeightList& getBoneWeights() { return _boneweights; }

            inline IndexList& getVertices() { return _vertexes; }

            inline void resetMatrix()
            {
                _result.set(0, 0, 0, 0,
                            0, 0, 0, 0,
                            0, 0, 0, 0,
                            0, 0, 0, 1);
            }
            inline void accummulateMatrix(const osg::Matrix& invBindMatrix, const osg::Matrix& matrix, osg::Matrix::value_type weight)
            {
                osg::Matrix m = invBindMatrix * matrix;
                osg::Matrix::value_type* ptr = m.ptr();
                osg::Matrix::value_type* ptrresult = _result.ptr();
                ptrresult[0] += ptr[0] * weight;
                ptrresult[1] += ptr[1] * weight;
                ptrresult[2] += ptr[2] * weight;

                ptrresult[4] += ptr[4] * weight;
                ptrresult[5] += ptr[5] * weight;
                ptrresult[6] += ptr[6] * weight;

                ptrresult[8] += ptr[8] * weight;
                ptrresult[9] += ptr[9] * weight;
                ptrresult[10] += ptr[10] * weight;

                ptrresult[12] += ptr[12] * weight;
                ptrresult[13] += ptr[13] * weight;
                ptrresult[14] += ptr[14] * weight;
            }
            inline void computeMatrixForVertexSet()
            {
                if (_boneweights.empty())
                {
                    osg::notify(osg::WARN) << this << " RigTransformSoftware::VertexGroup no bones found" << std::endl;
                    _result = osg::Matrix::identity();
                    return;
                }
                resetMatrix();

                for(BonePtrWeightList::iterator bwit=_boneweights.begin();bwit!=_boneweights.end();++bwit )
                {
                    const Bone* bone = bwit->getBonePtr();
                    if (!bone)
                    {
                        osg::notify(osg::WARN) << this << " RigTransformSoftware::computeMatrixForVertexSet Warning a bone is null, skip it" << std::endl;
                        continue;
                    }
                    const osg::Matrix& invBindMatrix = bone->getInvBindMatrixInSkeletonSpace();
                    const osg::Matrix& matrix = bone->getMatrixInSkeletonSpace();
                    osg::Matrix::value_type w = bwit->getWeight();
                    accummulateMatrix(invBindMatrix, matrix, w);
                }
            }
            inline const osg::Matrix& getMatrix() const { return _result;}
        protected:
            BonePtrWeightList _boneweights;
            IndexList _vertexes;
            osg::Matrix _result;
        };

        template <class V>
        inline void compute(const osg::Matrix& transform, const osg::Matrix& invTransform, const V* src, V* dst)
        {
            // the result of matrix mult should be cached to be used for vertexes transform and normal transform and maybe other computation
            for(VertexGroupList::iterator itvg=_uniqInfluenceSet2VertIDList.begin(); itvg!=_uniqInfluenceSet2VertIDList.end(); ++itvg)
            {
                VertexGroup& uniq = *itvg;
                uniq.computeMatrixForVertexSet();
                osg::Matrix matrix =  transform * uniq.getMatrix() * invTransform;

                const IndexList& vertexes = uniq.getVertices();
                for(IndexList::const_iterator vertIDit=vertexes.begin(); vertIDit!=vertexes.end(); ++vertIDit)
                {
                    dst[*vertIDit] = src[*vertIDit] * matrix;
                }

            }
        }


        template <class V>
        inline void computeNormal(const osg::Matrix& transform, const osg::Matrix& invTransform, const V* src, V* dst)
        {
            for(VertexGroupList::iterator itvg=_uniqInfluenceSet2VertIDList.begin(); itvg!=_uniqInfluenceSet2VertIDList.end(); ++itvg)
            {
                VertexGroup& uniq = *itvg;
                uniq.computeMatrixForVertexSet();
                osg::Matrix matrix =  transform * uniq.getMatrix() * invTransform;

                const IndexList& vertexes = uniq.getVertices();
                for(IndexList::const_iterator vertIDit=vertexes.begin(); vertIDit!=vertexes.end(); ++vertIDit)
                {
                    dst[*vertIDit] = osg::Matrix::transform3x3(src[*vertIDit],matrix);
                }
            }
        }

    protected:

        bool _needInit;

        std::map<std::string,bool> _invalidInfluence;

        typedef std::vector<VertexGroup> VertexGroupList;

        VertexGroupList _uniqInfluenceSet2VertIDList;
        void buildMinimumUpdateSet(const BoneMap&boneMap,const RigGeometry&rig );

    };
}

#endif