///////////////////////////////////////////////////////////////////////////////
//
// File: Advection.cpp
//
// 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.
//
///////////////////////////////////////////////////////////////////////////////

#include <SolverUtils/Advection/Advection.h>

namespace Nektar::SolverUtils
{

/**
 * @returns The advection factory.
 */
AdvectionFactory &GetAdvectionFactory()
{
    static AdvectionFactory instance;
    return instance;
}

template <typename DataType, typename TypeNekBlkMatSharedPtr>
void Advection::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)
{
    MultiRegions::ExpListSharedPtr tracelist = pFields[0]->GetTrace();
    std::shared_ptr<LocalRegions::ExpansionVector> traceExp =
        tracelist->GetExp();
    int ntotTrac   = (*traceExp).size();
    int nTracePnts = tracelist->GetTotPoints();
    int nTracPnt, nTracCoef;

    DNekMatSharedPtr tmp2Add;
    Array<OneD, DataType> MatData0;
    Array<OneD, NekDouble> MatData1;
    Array<OneD, NekDouble> MatData2;

    Array<OneD, DNekMatSharedPtr> TraceJacFwd(ntotTrac);
    Array<OneD, DNekMatSharedPtr> TraceJacBwd(ntotTrac);

    for (int nelmt = 0; nelmt < ntotTrac; nelmt++)
    {
        nTracCoef = (*traceExp)[nelmt]->GetNcoeffs();
        nTracPnt  = (*traceExp)[nelmt]->GetTotPoints();
        TraceJacFwd[nelmt] =
            MemoryManager<DNekMat>::AllocateSharedPtr(nTracCoef, nTracPnt, 0.0);
        TraceJacBwd[nelmt] =
            MemoryManager<DNekMat>::AllocateSharedPtr(nTracCoef, nTracPnt, 0.0);
    }

    std::shared_ptr<LocalRegions::ExpansionVector> fieldExp =
        pFields[0]->GetExp();
    int nTotElmt = (*fieldExp).size();
    int nElmtPnt, nElmtCoef;

    Array<OneD, DNekMatSharedPtr> ElmtJacQuad(nTotElmt);
    Array<OneD, DNekMatSharedPtr> ElmtJacCoef(nTotElmt);

    Array<OneD, NekDouble> SymmMatData;

    for (int nelmt = 0; nelmt < nTotElmt; nelmt++)
    {
        nElmtCoef = (*fieldExp)[nelmt]->GetNcoeffs();
        nElmtPnt  = (*fieldExp)[nelmt]->GetTotPoints();

        ElmtJacQuad[nelmt] =
            MemoryManager<DNekMat>::AllocateSharedPtr(nElmtCoef, nElmtPnt, 0.0);
        ElmtJacCoef[nelmt] = MemoryManager<DNekMat>::AllocateSharedPtr(
            nElmtCoef, nElmtCoef, 0.0);
    }

    bool TracePntJacGradflag = true;

    Array<OneD, Array<OneD, DataType>> TraceJacConsSign(2);
    for (int i = 0; i < 2; i++)
    {
        TraceJacConsSign[i] = Array<OneD, DataType>(nTracePnts, 1.0);
    }

    if (0 == TracePntJacGrad.size())
    {
        TracePntJacGradflag = false;
    }

    for (int m = 0; m < nConvectiveFields; m++)
    {
        for (int n = 0; n < nConvectiveFields; n++)
        {
            // ElmtJacCons to set 0
            for (int nelmt = 0; nelmt < nTotElmt; nelmt++)
            {
                (*ElmtJacCoef[nelmt]) = 0.0;
                (*ElmtJacQuad[nelmt]) = 0.0;
            }

            if (TracePntJacGradflag)
            {
                // only BJac is stored here because BJac = - FJac
                for (int ndir = 0; ndir < nSpaceDim; ndir++)
                {
                    // ElmtJacGrad to set 0
                    for (int nelmt = 0; nelmt < nTotElmt; nelmt++)
                    {
                        (*ElmtJacQuad[nelmt]) = 0.0;
                    }
                    int ngrad = n * nSpaceDim + ndir;

                    CalcJacobTraceInteg(pFields, m, ngrad, TracePntJacGrad,
                                        TracePntJacGradSign, TraceJacFwd,
                                        TraceJacBwd);
                    pFields[0]->AddTraceJacToElmtJac(TraceJacFwd, TraceJacBwd,
                                                     ElmtJacQuad);
                    // cost can be lower down by doing 3 directions together
                    pFields[0]->AddRightIPTPhysDerivBase(ndir, ElmtJacQuad,
                                                         ElmtJacCoef);
                }
                for (int nelmt = 0; nelmt < nTotElmt; nelmt++)
                {
                    nElmtCoef = (*fieldExp)[nelmt]->GetNcoeffs();
                    if (SymmMatData.size() < nElmtCoef)
                    {
                        SymmMatData =
                            Array<OneD, NekDouble>(nElmtCoef * nElmtCoef);
                    }
                    MatData1 = ElmtJacCoef[nelmt]->GetPtr();
                    for (int i = 0; i < nElmtCoef; i++)
                    {
                        Vmath::Vcopy(nElmtCoef, &MatData1[i * nElmtCoef], 1,
                                     &SymmMatData[i], nElmtCoef);
                    }
                    Vmath::Vadd(nElmtCoef * nElmtCoef, SymmMatData, 1, MatData1,
                                1, MatData1, 1);
                }
            }

            CalcJacobTraceInteg(pFields, m, n, TracePntJacCons,
                                TraceJacConsSign, TraceJacFwd, TraceJacBwd);

            pFields[0]->AddTraceJacToElmtJac(TraceJacFwd, TraceJacBwd,
                                             ElmtJacQuad);
            // Memory can be save to explore reusing ElmtJacQuad as output
            pFields[0]->AddRightIPTBaseMatrix(ElmtJacQuad, ElmtJacCoef);

            // add ElmtJacCons to gmtxarray[m][n]
            for (int nelmt = 0; nelmt < nTotElmt; nelmt++)
            {
                tmp2Add  = ElmtJacCoef[nelmt];
                MatData0 = gmtxarray[m][n]->GetBlock(nelmt, nelmt)->GetPtr();
                MatData1 = tmp2Add->GetPtr();
                for (int i = 0; i < MatData0.size(); i++)
                {
                    MatData0[i] += DataType(MatData1[i]);
                }
            }
        }
    }
}

template SOLVER_UTILS_EXPORT void Advection::AddTraceJacToMat(
    const int nConvectiveFields, const int nSpaceDim,
    const Array<OneD, MultiRegions::ExpListSharedPtr> &pFields,
    const Array<OneD, DNekBlkMatSharedPtr> &TracePntJacCons,
    Array<OneD, Array<OneD, DNekBlkMatSharedPtr>> &gmtxarray,
    const Array<OneD, DNekBlkMatSharedPtr> &TracePntJacGrad,
    const Array<OneD, Array<OneD, NekDouble>> &TracePntJacGradSign);
template SOLVER_UTILS_EXPORT void Advection::AddTraceJacToMat(
    const int nConvectiveFields, const int nSpaceDim,
    const Array<OneD, MultiRegions::ExpListSharedPtr> &pFields,
    const Array<OneD, SNekBlkMatSharedPtr> &TracePntJacCons,
    Array<OneD, Array<OneD, SNekBlkMatSharedPtr>> &gmtxarray,
    const Array<OneD, SNekBlkMatSharedPtr> &TracePntJacGrad,
    const Array<OneD, Array<OneD, NekSingle>> &TracePntJacGradSign);

/**
 *
 */
template <typename DataType, typename TypeNekBlkMatSharedPtr>
void Advection::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)
{
    MultiRegions::ExpListSharedPtr tracelist = pFields[0]->GetTrace();
    std::shared_ptr<LocalRegions::ExpansionVector> traceExp =
        tracelist->GetExp();
    int ntotTrac = (*traceExp).size();
    int nTracPnt, noffset, pntoffset;

    Array<OneD, int> tracepnts(ntotTrac);
    Array<OneD, Array<OneD, NekDouble>> JacFwd(ntotTrac);
    Array<OneD, Array<OneD, NekDouble>> JacBwd(ntotTrac);

    for (int nelmt = 0; nelmt < ntotTrac; nelmt++)
    {
        nTracPnt         = (*traceExp)[nelmt]->GetTotPoints();
        tracepnts[nelmt] = nTracPnt;

        JacFwd[nelmt] = Array<OneD, NekDouble>(nTracPnt, 0.0);
        JacBwd[nelmt] = Array<OneD, NekDouble>(nTracPnt, 0.0);
    }

    DataType ftmp, btmp;
    for (int nelmt = 0; nelmt < ntotTrac; nelmt++)
    {
        nTracPnt = tracepnts[nelmt];
        noffset  = tracelist->GetPhys_Offset(nelmt);
        for (int npnt = 0; npnt < nTracPnt; npnt++)
        {
            pntoffset = noffset + npnt;
            ftmp      = (*PntJac[0]->GetBlock(pntoffset, pntoffset))(m, n);
            JacFwd[nelmt][npnt] = NekDouble(PntJacSign[0][pntoffset] * ftmp);

            btmp = (*PntJac[1]->GetBlock(pntoffset, pntoffset))(m, n);
            JacBwd[nelmt][npnt] = NekDouble(PntJacSign[1][pntoffset] * btmp);
        }
    }
    tracelist->GetDiagMatIpwrtBase(JacFwd, TraceJacFwd);
    tracelist->GetDiagMatIpwrtBase(JacBwd, TraceJacBwd);
}

/**
 * This function should be overridden in derived classes to initialise the
 * specific advection data members. However, this base class function should
 * be called as the first statement of the overridden function to ensure the
 * base class is correctly initialised in order.
 *
 * @param   pSession            Session information.
 * @param   pFields             Expansion lists for scalar fields.
 */
void Advection::v_InitObject(
    const LibUtilities::SessionReaderSharedPtr pSession,
    Array<OneD, MultiRegions::ExpListSharedPtr> pFields)
{
    m_spaceDim = pFields[0]->GetCoordim(0);

    if (pSession->DefinesSolverInfo("HOMOGENEOUS"))
    {
        std::string HomoStr = pSession->GetSolverInfo("HOMOGENEOUS");
        if (HomoStr == "HOMOGENEOUS1D" || HomoStr == "Homogeneous1D" ||
            HomoStr == "1D" || HomoStr == "Homo1D" ||
            HomoStr == "HOMOGENEOUS2D" || HomoStr == "Homogeneous2D" ||
            HomoStr == "2D" || HomoStr == "Homo2D")
        {
            m_spaceDim++;
        }
        else
        {
            NEKERROR(ErrorUtil::efatal,
                     "Only 1D homogeneous dimension supported.");
        }
    }
}

/**
 *
 */
void Advection::v_SetBaseFlow(
    [[maybe_unused]] const Array<OneD, Array<OneD, NekDouble>> &inarray,
    [[maybe_unused]] const Array<OneD, MultiRegions::ExpListSharedPtr> &fields)
{
    NEKERROR(ErrorUtil::efatal,
             "A baseflow is not appropriate for this advection type.");
}

} // namespace Nektar::SolverUtils
