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#ifndef OSD_CPU_EVAL_LIMIT_CONTEXT_H
#define OSD_CPU_EVAL_LIMIT_CONTEXT_H

#include "../version.h"

#include "../osd/evalLimitContext.h"
#include "../osd/vertexDescriptor.h"

#include <map>
#include <stdio.h>

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

class OsdCpuEvalLimitContext : public OsdEvalLimitContext {
public:
    /// \brief Factory
    /// Returns an EvalLimitContext from the given farmesh.
    /// Note : the farmesh is expected to be feature-adaptive and have ptex
    ///        coordinates tables.
    static OsdCpuEvalLimitContext * Create(FarMesh<OsdVertex> const * farmesh);

    /// Destructor
    virtual ~OsdCpuEvalLimitContext();


    /// Binds the data buffers.
    ///
    /// @param inDesc vertex buffer data descriptor shared by all input data buffers
    ///
    /// @param inQ input vertex data
    ///
    /// @param outDesc vertex buffer data descriptor shared by all output data buffers
    ///
    /// @param outQ output vertex data
    ///
    /// @param outdQu optional output derivative along "u" of the vertex data
    ///
    /// @param outdQv optional output derivative along "v" of the vertex data
    ///
    template<class VERTEX_BUFFER, class OUTPUT_BUFFER>
    void BindVertexBuffers( OsdVertexBufferDescriptor const & inDesc, VERTEX_BUFFER *inQ,
                            OsdVertexBufferDescriptor const & outDesc, OUTPUT_BUFFER *outQ, 
                                                                       OUTPUT_BUFFER *outdQu=0, 
                                                                       OUTPUT_BUFFER *outdQv=0) {
        _inDesc = inDesc;
        _inQ = inQ ? inQ->BindCpuBuffer() : 0;
 
        _outDesc = outDesc;
        _outQ   = outQ ? outQ->BindCpuBuffer() : 0 ;
        _outdQu = outdQu ? outdQu->BindCpuBuffer() : 0 ;
        _outdQv = outdQv ? outdQv->BindCpuBuffer() : 0 ;
    }

    /// Unbind the data buffers
    void UnbindVertexBuffers() {
        _inQ    = 0;
        _outQ   = 0;
        _outdQu = 0;
        _outdQv = 0;
    }

    /// Returns the input vertex buffer descriptor
    const OsdVertexBufferDescriptor & GetInputDesc() const {
        return _inDesc;
    }

    /// Returns the output vertex buffer descriptor
    const OsdVertexBufferDescriptor & GetOutputDesc() const {
        return _outDesc;
    }

    /// Returns the input vertex buffer data
    float const * GetInputVertexData() const {
        return _inQ;
    }

    /// Returns the output vertex buffer data
    float * GetOutputVertexData() const {
        return _outQ;
    }

    /// Returns the U derivative of the output vertex buffer data
    float * GetOutputVertexDataUDerivative() const {
        return _outdQu;
    }

    /// Returns the V derivative of the output vertex buffer data
    float * GetOutputVertexDataVDerivative() const {
        return _outdQv;
    }
    
    /// Returns the vector of patch arrays
    const OsdPatchArrayVector & GetPatchArrayVector() const {
        return _patchArrays;
    }
    
    /// Returns the vector of per-patch parametric data
    const std::vector<FarPtexCoord::BitField> & GetPatchBitFields() const {
        return _patchBitFields;
    }

    /// The ordered array of control vertex indices for all the patches
    const std::vector<unsigned int> & GetControlVertices() const {
        return _patchBuffer;
    }

    /// XXXX
    const int * GetVertexValenceBuffer() const {
        return &_vertexValenceBuffer[0];
    }

    const unsigned int *GetQuadOffsetBuffer() const {
        return &_quadOffsetBuffer[0];
    }

    /// Maps coarse-face ptex coordinates to children patches
    struct PatchMap {
    public:
        
        
        /// \brief Returns the number and list of patch indices for a given face.
        ///
        /// PatchMaps map coarse faces to their childrn feature adaptive patches. 
        /// Coarse faces are indexed using their ptex face ID to resolve parametric
        /// ambiguity on non-quad faces. Note : this "map" is actually a vector, so
        /// queries are O(1) order.
        ///
        /// @param faceid the ptex face index to search for
        ///
        /// @param npatches the number of children patches found for the faceid
        ///
        /// @param patches a set of pointers to the individual patch handles
        ///
        bool GetChildPatchesHandles( int faceid, int * npatches, OsdPatchHandle const ** patches ) const {

            if (_handles.empty() or _offsets.empty() or (faceid>=(int)_offsets.size()))
                return false;
            
            *npatches = (faceid==(int)_offsets.size()-1 ? (unsigned int)_handles.size()-1 : _offsets[faceid+1]) - _offsets[faceid] + 1;
            
            *patches = &_handles[ _offsets[faceid] ];
            
            return true;
        }
    
    private:
    
        friend class OsdCpuEvalLimitContext;
               
        typedef std::multimap<unsigned int, OsdPatchHandle> MultiMap;
        
        // Inserts the patches from the array into the multimap
        int _AddPatchArray( int arrayid, int ringsize,
                            FarPatchTables::PtexCoordinateTable const & ptxtable,
                            int & nfaces, MultiMap & mmap ) {
            
            if (ptxtable.empty())
                return 0;
            
            for (int i=0; i<(int)ptxtable.size(); ++i) {

                int faceId = ptxtable[i].faceIndex;
                
                OsdPatchHandle handle = { arrayid, i*ringsize, (unsigned int)mmap.size() };
                
                mmap.insert( std::pair<unsigned int, OsdPatchHandle>(faceId, handle) );
                
                nfaces = std::max(nfaces, faceId);
            }
            
            return 1;
        }

        // Constructor
        PatchMap( FarPatchTables const & patchTables ) {
                  
            int npatches = (int)patchTables.GetNumPatches();
            
            _handles.reserve(npatches);
            
            MultiMap mmap;
            
            // Insert all the patch arrays into the map
            int arrayId=0, nfaces=0;
            
            arrayId+=_AddPatchArray( arrayId, 
                                     patchTables.GetRegularPatchRingsize(),
                                     patchTables.GetFullRegularPtexCoordinates(), 
                                     nfaces, mmap );

            arrayId+=_AddPatchArray( arrayId, 
                                     patchTables.GetBoundaryPatchRingsize(),
                                     patchTables.GetFullBoundaryPtexCoordinates(), 
                                     nfaces, mmap );
                                     
            arrayId+=_AddPatchArray( arrayId, 
                                     patchTables.GetCornerPatchRingsize(),
                                     patchTables.GetFullCornerPtexCoordinates(), 
                                     nfaces, mmap );
                                     
            arrayId+=_AddPatchArray( arrayId, 
                                     patchTables.GetGregoryPatchRingsize(), 
                                     patchTables.GetFullGregoryPtexCoordinates(), 
                                     nfaces, mmap );
            
            for (unsigned char pattern=0; pattern<5; ++pattern) {
            
                arrayId+=_AddPatchArray( arrayId, 
                                         patchTables.GetRegularPatchRingsize(), 
                                         patchTables.GetTransitionRegularPtexCoordinates(pattern), 
                                         nfaces, mmap );

                for (unsigned char rot=0; rot<4; ++rot) {
                
                    arrayId+=_AddPatchArray( arrayId, 
                                             patchTables.GetBoundaryPatchRingsize(),
                                             patchTables.GetTransitionBoundaryPtexCoordinates(pattern, rot), 
                                             nfaces, mmap );
                                             
                    arrayId+=_AddPatchArray( arrayId, 
                                             patchTables.GetCornerPatchRingsize(),
                                             patchTables.GetTransitionCornerPtexCoordinates(pattern, rot), 
                                             nfaces, mmap );
                }
            }

            ++nfaces;

            _handles.resize( mmap.size() );
            
            _offsets.reserve( nfaces );
            _offsets.push_back(0);

            unsigned int handlesIdx = 0, faceId=mmap.begin()->first;

            // Serialize the multi-map
            for (MultiMap::const_iterator it=mmap.begin(); it!=mmap.end(); ++it, ++handlesIdx) {
                        
                assert(it->first >= faceId);
                
                if (it->first != faceId) {

                    faceId = it->first;
                    
                    // position the offset marker to the new face                    
                    _offsets.push_back( handlesIdx );
                }
                
                // copy the patch id into the table
                _handles[handlesIdx] = it->second;
            }
        }

        // Patch handle allowing location of individual patch data inside patch
        // arrays or in serialized form
        std::vector<OsdPatchHandle> _handles;
        
        // offset to the first handle of the child patches for each coarse face
        std::vector<unsigned int> _offsets; 
    };

    /// Returns a map object that can connect a faceId to a list of children patches
    const PatchMap * GetPatchesMap() const {
        return _patchMap;
    }

protected:
    explicit OsdCpuEvalLimitContext(FarMesh<OsdVertex> const * farmesh);

private:

    //--------------------------------------------------------------------------
    int _AppendPatchArray( OsdPatchDescriptor const & desc,
                           FarPatchTables::PTable const & pT, 
                           FarPatchTables::PtexCoordinateTable const & ptxT );


    // Topology data for a mesh
    OsdPatchArrayVector                 _patchArrays;    // patch descriptor for each patch in the mesh
    std::vector<FarPtexCoord::BitField> _patchBitFields; // per-patch parametric info
    std::vector<unsigned int>           _patchBuffer;    // list of control vertices
    
    std::vector<int>           _vertexValenceBuffer;     // extra Gregory patch data buffers
    std::vector<unsigned int>  _quadOffsetBuffer;

    PatchMap * _patchMap;

    OsdVertexBufferDescriptor _inDesc,
                              _outDesc;
    
    float * _inQ,      // input vertex data
          * _outQ,     // output vertex data
          * _outdQu,   // U derivative of output vertex data
          * _outdQv;   // V derivative of output vertex data
};

} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;

} // end namespace OpenSubdiv

#endif /* OSD_CPU_EVAL_LIMIT_CONTEXT_H */