///////////////////////////////////////////////////////////////////////////////
//
// File: Helmholtz2D_MFO.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:
//
///////////////////////////////////////////////////////////////////////////////

#include <cstdio>
#include <cstdlib>

#include <Collections/Collection.h>
#include <LibUtilities/BasicUtils/SessionReader.h>
#include <LibUtilities/Communication/Comm.h>
#include <LibUtilities/Memory/NekMemoryManager.hpp>
#include <MultiRegions/ContField.h>
#include <MultiRegions/ExpList.h>
#include <SpatialDomains/MeshGraphIO.h>

using namespace std;
using namespace Nektar;

// #define TIMING
#ifdef TIMING
#include <time.h>
#define Timing(s)                                                              \
    fprintf(stdout, "%s Took %g seconds\n", s,                                 \
            (clock() - st) / (double)CLOCKS_PER_SEC);                          \
    st = clock();
#else
#define Timing(s) /* Nothing */
#endif

int main(int argc, char *argv[])
{
    LibUtilities::SessionReaderSharedPtr vSession =
        LibUtilities::SessionReader::CreateInstance(argc, argv);

    MultiRegions::ContFieldSharedPtr Exp, Fce;
    int i, nq, coordim;
    Array<OneD, NekDouble> fce;
    Array<OneD, NekDouble> xc0, xc1, xc2;
    StdRegions::ConstFactorMap factors;
    StdRegions::VarCoeffMap varcoeffs;

    if (argc < 2)
    {
        fprintf(stderr, "Usage: Helmholtz2D meshfile [SysSolnType]   or   \n");
        exit(1);
    }

    try
    {
        LibUtilities::FieldIOSharedPtr fld =
            LibUtilities::FieldIO::CreateDefault(vSession);

        //----------------------------------------------
        // Read in mesh from input file
        SpatialDomains::MeshGraphSharedPtr graph2D =
            SpatialDomains::MeshGraphIO::Read(vSession);
        //----------------------------------------------

        //----------------------------------------------
        // Print summary of solution details
        factors[StdRegions::eFactorLambda] = vSession->GetParameter("Lambda");
        const SpatialDomains::ExpansionInfoMap &expansions =
            graph2D->GetExpansionInfo();
        LibUtilities::BasisKey bkey0 =
            expansions.begin()->second->m_basisKeyVector[0];

        if (vSession->GetComm()->GetRank() == 0)
        {
            cout << "Solving 2D Helmholtz: " << endl;
            cout << "         Communication: " << vSession->GetComm()->GetType()
                 << endl;
            cout << "         Solver type  : "
                 << vSession->GetSolverInfo("GlobalSysSoln") << endl;
            cout << "         Lambda       : "
                 << factors[StdRegions::eFactorLambda] << endl;
            cout << "         No. modes    : " << bkey0.GetNumModes() << endl;
            cout << endl;
        }
        //----------------------------------------------

        //----------------------------------------------
        // Define Expansion
        int imp = 5; // 2=iterperexp, 5=matrixfreeops
        Collections::ImplementationType impType =
            (Collections::ImplementationType)imp;

        Exp = MemoryManager<MultiRegions::ContField>::AllocateSharedPtr(
            vSession, graph2D, vSession->GetVariable(0));
        Exp->CreateCollections(impType);

        std::cout << "Using " << Collections::ImplementationTypeMap[imp]
                  << " Collection Implementation:" << std::endl;

        //----------------------------------------------

        Timing("Read files and define exp ..");

        //----------------------------------------------
        // Set up coordinates of mesh for Forcing function evaluation
        coordim = Exp->GetCoordim(0);
        nq      = Exp->GetTotPoints();

        xc0 = Array<OneD, NekDouble>(nq, 0.0);
        xc1 = Array<OneD, NekDouble>(nq, 0.0);
        xc2 = Array<OneD, NekDouble>(nq, 0.0);

        switch (coordim)
        {
            case 2:
                Exp->GetCoords(xc0, xc1);
                break;
            case 3:
                Exp->GetCoords(xc0, xc1, xc2);
                break;
            default:
                ASSERTL0(false, "Coordim not valid");
                break;
        }
        //----------------------------------------------

        //----------------------------------------------
        // Set up variable coefficients if defined
        if (vSession->DefinesFunction("d00"))
        {
            Array<OneD, NekDouble> d00(nq, 0.0);
            LibUtilities::EquationSharedPtr d00func =
                vSession->GetFunction("d00", 0);
            d00func->Evaluate(xc0, xc1, xc2, d00);
            varcoeffs[StdRegions::eVarCoeffD00] = d00;
        }

        if (vSession->DefinesFunction("d01"))
        {
            Array<OneD, NekDouble> d01(nq, 0.0);
            LibUtilities::EquationSharedPtr d01func =
                vSession->GetFunction("d01", 0);
            d01func->Evaluate(xc0, xc1, xc2, d01);
            varcoeffs[StdRegions::eVarCoeffD01] = d01;
        }

        if (vSession->DefinesFunction("d11"))
        {
            Array<OneD, NekDouble> d11(nq, 0.0);
            LibUtilities::EquationSharedPtr d11func =
                vSession->GetFunction("d11", 0);
            d11func->Evaluate(xc0, xc1, xc2, d11);
            varcoeffs[StdRegions::eVarCoeffD11] = d11;
        }
        //----------------------------------------------

        //----------------------------------------------
        // Set up const diffusion coefficients if defined
        if (vSession->DefinesParameter("d00"))
        {
            NekDouble d00;
            vSession->LoadParameter("d00", d00, 1.0);
            factors[StdRegions::eFactorCoeffD00] = d00;
        }

        if (vSession->DefinesParameter("d01"))
        {
            NekDouble d01;
            vSession->LoadParameter("d01", d01, 1.0);
            factors[StdRegions::eFactorCoeffD01] = d01;
        }

        if (vSession->DefinesParameter("d11"))
        {
            NekDouble d11;
            vSession->LoadParameter("d11", d11, 1.0);
            factors[StdRegions::eFactorCoeffD11] = d11;
        }

        if (vSession->DefinesParameter("fn_vardiff"))
        {
            NekDouble tau;
            vSession->LoadParameter("fn_vardiff", tau, 1.0);
            if (tau > 0)
            {
                factors[StdRegions::eFactorTau] = 1.0;
            }
        }
        //----------------------------------------------

        //----------------------------------------------
        // Define forcing function for first variable defined in file
        fce = Array<OneD, NekDouble>(nq);
        LibUtilities::EquationSharedPtr ffunc =
            vSession->GetFunction("Forcing", 0);
        ffunc->Evaluate(xc0, xc1, xc2, fce);

        //----------------------------------------------

        //----------------------------------------------
        // Setup expansion containing the  forcing function
        Fce = MemoryManager<MultiRegions::ContField>::AllocateSharedPtr(*Exp);
        Fce->SetPhys(fce);
        //----------------------------------------------
        Timing("Define forcing ..");

        //----------------------------------------------
        // Helmholtz solution taking physical forcing after setting
        // initial condition to zero
        Vmath::Zero(Exp->GetNcoeffs(), Exp->UpdateCoeffs(), 1);

        Exp->HelmSolve(Fce->GetPhys(), Exp->UpdateCoeffs(), factors, varcoeffs);
        //----------------------------------------------
        Timing("Helmholtz Solve ..");

#ifdef TIMING
        for (i = 0; i < 20; ++i)
        {
            Vmath::Zero(Exp->GetNcoeffs(), Exp->UpdateCoeffs(), 1);
            Exp->HelmSolve(Fce->GetPhys(), Exp->UpdateCoeffs(), factors,
                           varcoeffs);
        }

        Timing("20 Helmholtz Solves:... ");
#endif

        //----------------------------------------------
        // Backward Transform Solution to get solved values
        Exp->BwdTrans(Exp->GetCoeffs(), Exp->UpdatePhys());
        //----------------------------------------------

        //-----------------------------------------------
        // Write solution to file
        string out = vSession->GetSessionName() + ".fld";
        std::vector<LibUtilities::FieldDefinitionsSharedPtr> FieldDef =
            Exp->GetFieldDefinitions();
        std::vector<std::vector<NekDouble>> FieldData(FieldDef.size());

        for (i = 0; i < FieldDef.size(); ++i)
        {
            FieldDef[i]->m_fields.push_back("u");
            Exp->AppendFieldData(FieldDef[i], FieldData[i]);
        }
        fld->Write(out, FieldDef, FieldData);
        //-----------------------------------------------

        //----------------------------------------------
        // See if there is an exact solution, if so
        // evaluate and plot errors
        LibUtilities::EquationSharedPtr ex_sol =
            vSession->GetFunction("ExactSolution", 0);

        if (ex_sol)
        {
            //----------------------------------------------
            // evaluate exact solution
            ex_sol->Evaluate(xc0, xc1, xc2, fce);

            Fce->SetPhys(fce);
            Fce->SetPhysState(true);
            //--------------------------------------------

            //--------------------------------------------
            // Calculate errors
            NekDouble vLinfError = Exp->Linf(Exp->GetPhys(), Fce->GetPhys());
            NekDouble vL2Error   = Exp->L2(Exp->GetPhys(), Fce->GetPhys());
            NekDouble vH1Error   = Exp->H1(Exp->GetPhys(), Fce->GetPhys());
            if (vSession->GetComm()->GetRank() == 0)
            {
                cout << "L infinity error: " << vLinfError << endl;
                cout << "L 2 error:        " << vL2Error << endl;
                cout << "H 1 error:        " << vH1Error << endl;
            }
            //--------------------------------------------
        }
        //----------------------------------------------
    }
    catch (const std::runtime_error &)
    {
        cout << "Caught an error" << endl;
        return 1;
    }

    vSession->Finalise();

    return 0;
}
