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/*!
 * \file
 * \ingroup CCMpfaDiscretization
 * \brief Helper class to be used to obtain lambda functions for the tensors
 *        involved in the laws that describe the different kind of fluxes that
 *        occur in DuMuX models (i.e. advective, diffusive and heat conduction fluxes).
 *        The local systems appearing in Mpfa methods have to be solved subject to
 *        the different tensors. This class returns lambda expressions to be used in the
 *        local systems. The specialization for other discretization methods allows
 *        compatibility with the TPFA scheme, which could be used for one or more of the tensors.
 */
#ifndef DUMUX_DISCRETIZATION_MPFA_TENSOR_LAMBDA_FACTORY_HH
#define DUMUX_DISCRETIZATION_MPFA_TENSOR_LAMBDA_FACTORY_HH

#include <dumux/common/properties.hh>

#include <dumux/discretization/methods.hh>
#include <dumux/discretization/cellcentered/mpfa/tensorlambdafactory.hh>

namespace Dumux
{

/*!
 * \ingroup CCMpfaDiscretization
 * \brief Helper class to be used to obtain lambda functions for the tensors
 *        involved in the laws that describe the different kind of fluxes that
 *        occur in DuMuX models (i.e. advective, diffusive and heat conduction fluxes).
 *        The local systems appearing in Mpfa methods have to be solved subject to
 *        the different tensors. This class returns lambda expressions to be used in the
 *        local systems. The specialization for discretization methods other than mpfa allows
 *        compatibility with the TPFA scheme, which could be used for one or more of the tensors.
 *        The interfaces of the lambdas are chosen such that all involved tensors can be extracted
 *        with the given arguments.
 */
template<class TypeTag, DiscretizationMethods Method>
class TensorLambdaFactory
{
public:

    //! We return zero scalars here in the functions below.
    //! We have to return something as the local systems expect a type
    //! to perform actions on, thus a compiler error will occur.
    //! We return 0.0 as this call should never happen for a tensor
    //! which is not treated by an mpfa method anyway.

    //! lambda for the law describing the advective term
    static auto getAdvectionLambda()
    {
        return [] (const auto& problem,
                   const auto& element,
                   const auto& volVars,
                   const auto& fvGeometry,
                   const auto& scv)
               { return 0.0; };
    }

    //! lambda for the diffusion coefficient/tensor
    static auto getDiffusionLambda(unsigned int phaseIdx, unsigned int compIdx)
    {
        return [] (const auto& problem,
                   const auto& element,
                   const auto& volVars,
                   const auto& fvGeometry,
                   const auto& scv)
               { return 0.0; };
    }

    //! lambda for the fourier coefficient
    static auto getHeatConductionLambda()
    {
        return [] (const auto& problem,
                   const auto& element,
                   const auto& volVars,
                   const auto& fvGeometry,
                   const auto& scv)
               { return 0.0; };
    }
};

//! Specialization for mpfa schemes
template<class TypeTag>
class TensorLambdaFactory<TypeTag, DiscretizationMethods::CCMpfa>
{
public:

    //! return void lambda here
    static auto getAdvectionLambda()
    {
        return [] (const auto& problem,
                   const auto& element,
                   const auto& volVars,
                   const auto& fvGeometry,
                   const auto& scv)
               { return volVars.permeability(); };
    }

    //! return void lambda here
    static auto getDiffusionLambda(unsigned int phaseIdx, unsigned int compIdx)
    {
        return [phaseIdx, compIdx] (const auto& problem,
                                    const auto& element,
                                    const auto& volVars,
                                    const auto& fvGeometry,
                                    const auto& scv)
               { return volVars.diffusionCoefficient(phaseIdx, compIdx); };
    }

    //! return void lambda here
    static auto getHeatConductionLambda()
    {
        using ThermalConductivityModel = typename GET_PROP_TYPE(TypeTag, ThermalConductivityModel);

        return [] (const auto& problem,
                   const auto& element,
                   const auto& volVars,
                   const auto& fvGeometry,
                   const auto& scv)
               { return ThermalConductivityModel::effectiveThermalConductivity(volVars,
                                                                               problem.spatialParams(),
                                                                               element,
                                                                               fvGeometry,
                                                                               scv); };
    }
};

} // end namespace

#endif