// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_GFE_PARALLEL_P2MAPPER_HH
#define DUNE_GFE_PARALLEL_P2MAPPER_HH

#include <dune/geometry/type.hh>
#include <dune/common/typetraits.hh>

#include <dune/functions/functionspacebases/pqknodalbasis.hh>

/** \brief Mimic a dune-grid mapper for a P2 space, using the dune-functions dof ordering of such a space
 */
template<class GridView>
class P2BasisMapper
{
  typedef typename GridView::Grid::template Codim<0>::Entity Element;
public:

  typedef typename Dune::Functions::PQkNodalBasis<GridView,2>::MultiIndex::value_type Index;

  P2BasisMapper(const GridView& gridView)
  : p2Basis_(gridView)
  {}

  std::size_t size() const
  {
    return p2Basis_.size();
  }

  template <class Entity>
  bool contains(const Entity& entity, uint subEntity, uint codim, Index& result) const
  {
    auto localView = p2Basis_.localView();
    auto localIndexSet = p2Basis_.localIndexSet();
    localView.bind(entity);
    localIndexSet.bind(localView);

    for (size_t i=0; i<localIndexSet.size(); i++)
    {
      if (localView.tree().finiteElement().localCoefficients().localKey(i).subEntity() == subEntity
          and localView.tree().finiteElement().localCoefficients().localKey(i).codim() == codim)
      {
        result = localIndexSet.index(i)[0];
        return true;
      }
    }

    return false;
  }

  Dune::Functions::PQkNodalBasis<GridView,2> p2Basis_;
};

#endif