///////////////////////////////////////////////////////////////////////////////
//
// File: Advection.h
//
// For more information, please see: http://www.nektar.info
//
// The MIT License
//
// Copyright (c) 2006 Division of Applied Mathematics, Brown University (USA),
// Department of Aeronautics, Imperial College London (UK), and Scientific
// Computing and Imaging Institute, University of Utah (USA).
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
// Description: Abstract base class for advection.
//
///////////////////////////////////////////////////////////////////////////////

#ifndef NEKTAR_SOLVERUTILS_ADVECTION
#define NEKTAR_SOLVERUTILS_ADVECTION

#include <functional>
#include <string>

#include <LibUtilities/BasicUtils/NekFactory.hpp>
#include <LibUtilities/BasicUtils/SharedArray.hpp>
#include <MultiRegions/ExpList.h>
#include <SolverUtils/RiemannSolvers/RiemannSolver.h>
#include <SolverUtils/SolverUtilsDeclspec.h>
#include <iomanip>

namespace Nektar::SolverUtils
{

class Advection;

/// A shared pointer to an Advection object.
typedef std::shared_ptr<Advection> AdvectionSharedPtr;

/// Datatype of the NekFactory used to instantiate classes derived
/// from the Advection class.
typedef LibUtilities::NekFactory<std::string, Advection, std::string>
    AdvectionFactory;

/// Gets the factory for initialising advection objects.
SOLVER_UTILS_EXPORT AdvectionFactory &GetAdvectionFactory();

/**
 * Defines a callback function type which evaluates the flux vector \f$ F(u) \f$
 * in a conservative advection of the form \f$ \nabla\cdot F(u) \f$.
 */
typedef std::function<void(const Array<OneD, Array<OneD, NekDouble>> &,
                           Array<OneD, Array<OneD, Array<OneD, NekDouble>>> &)>
    AdvectionFluxVecCB;

/**
 * @brief An abstract base class encapsulating the concept of advection
 * of a vector field.
 *
 * Subclasses override the Advection::v_InitObject function to
 * initialise the object and the Advection::v_Advect function to
 * evaluate the advection of the vector field.
 */
class Advection
{
public:
    /// Interface function to initialise the advection object.
    SOLVER_UTILS_EXPORT void InitObject(
        LibUtilities::SessionReaderSharedPtr pSession,
        Array<OneD, MultiRegions::ExpListSharedPtr> pFields)
    {
        v_InitObject(pSession, pFields);
    }

    /// Interface function to advect the vector field.
    SOLVER_UTILS_EXPORT void Advect(
        const int nConvectiveFields,
        const Array<OneD, MultiRegions::ExpListSharedPtr> &fields,
        const Array<OneD, Array<OneD, NekDouble>> &advVel,
        const Array<OneD, Array<OneD, NekDouble>> &inarray,
        Array<OneD, Array<OneD, NekDouble>> &outarray, const NekDouble &time,
        const Array<OneD, Array<OneD, NekDouble>> &pFwd =
            NullNekDoubleArrayOfArray,
        const Array<OneD, Array<OneD, NekDouble>> &pBwd =
            NullNekDoubleArrayOfArray)
    {
        v_Advect(nConvectiveFields, fields, advVel, inarray, outarray, time,
                 pFwd, pBwd);
    }

    /**
     * @brief Set the flux vector callback function.
     *
     * This routine is a utility function to avoid the explicit use of
     * std::bind. A function and object can be passed to this function
     * instead.
     */
    template <typename FuncPointerT, typename ObjectPointerT>
    void SetFluxVector(FuncPointerT func, ObjectPointerT obj)
    {
        m_fluxVector =
            std::bind(func, obj, std::placeholders::_1, std::placeholders::_2);
    }

    /**
     * @brief Set a Riemann solver object for this advection object.
     *
     * @param riemann  The RiemannSolver object.
     */
    inline void SetRiemannSolver(RiemannSolverSharedPtr riemann)
    {
        m_riemann = riemann;
    }

    /**
     * @brief Set the flux vector callback function.
     *
     * @param fluxVector  The callback function to override.
     */
    inline void SetFluxVector(AdvectionFluxVecCB fluxVector)
    {
        m_fluxVector = fluxVector;
    }

    /**
     * @brief Set the base flow used for linearised advection objects.
     *
     * @param inarray   Vector to use as baseflow
     */
    inline void SetBaseFlow(
        const Array<OneD, Array<OneD, NekDouble>> &inarray,
        const Array<OneD, MultiRegions::ExpListSharedPtr> &fields)
    {
        v_SetBaseFlow(inarray, fields);
    }

    template <typename DataType, typename TypeNekBlkMatSharedPtr>
    SOLVER_UTILS_EXPORT void AddTraceJacToMat(
        const int nConvectiveFields, const int nSpaceDim,
        const Array<OneD, MultiRegions::ExpListSharedPtr> &pFields,
        const Array<OneD, TypeNekBlkMatSharedPtr> &TracePntJacCons,
        Array<OneD, Array<OneD, TypeNekBlkMatSharedPtr>> &gmtxarray,
        const Array<OneD, TypeNekBlkMatSharedPtr> &TracePntJacGrad,
        const Array<OneD, Array<OneD, DataType>> &TracePntJacGradSign);

    template <typename DataType, typename TypeNekBlkMatSharedPtr>
    void CalcJacobTraceInteg(
        const Array<OneD, MultiRegions::ExpListSharedPtr> &pFields, const int m,
        const int n, const Array<OneD, const TypeNekBlkMatSharedPtr> &PntJac,
        const Array<OneD, const Array<OneD, DataType>> &PntJacSign,
        Array<OneD, DNekMatSharedPtr> &TraceJacFwd,
        Array<OneD, DNekMatSharedPtr> &TraceJacBwd);

protected:
    SOLVER_UTILS_EXPORT virtual ~Advection() = default;

    /// Callback function to the flux vector (set when advection is in
    /// conservative form).
    AdvectionFluxVecCB m_fluxVector;
    /// Riemann solver for DG-type schemes.
    RiemannSolverSharedPtr m_riemann;
    /// Storage for space dimension. Used for homogeneous extension.
    int m_spaceDim;

    /// Initialises the advection object.
    SOLVER_UTILS_EXPORT virtual void v_InitObject(
        LibUtilities::SessionReaderSharedPtr pSession,
        Array<OneD, MultiRegions::ExpListSharedPtr> pFields);

    /// Advects a vector field.
    SOLVER_UTILS_EXPORT virtual void v_Advect(
        const int nConvectiveFields,
        const Array<OneD, MultiRegions::ExpListSharedPtr> &fields,
        const Array<OneD, Array<OneD, NekDouble>> &advVel,
        const Array<OneD, Array<OneD, NekDouble>> &inarray,
        Array<OneD, Array<OneD, NekDouble>> &outarray, const NekDouble &time,
        const Array<OneD, Array<OneD, NekDouble>> &pFwd =
            NullNekDoubleArrayOfArray,
        const Array<OneD, Array<OneD, NekDouble>> &pBwd =
            NullNekDoubleArrayOfArray) = 0;

    /// Overrides the base flow used during linearised advection
    SOLVER_UTILS_EXPORT virtual void v_SetBaseFlow(
        const Array<OneD, Array<OneD, NekDouble>> &inarray,
        const Array<OneD, MultiRegions::ExpListSharedPtr> &fields);
};

} // namespace Nektar::SolverUtils

#endif
