///////////////////////////////////////////////////////////////////////////////
//
// File: Helmholtz1D.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 <LibUtilities/BasicUtils/SessionReader.h>
#include <LibUtilities/Communication/Comm.h>
#include <LibUtilities/Memory/NekMemoryManager.hpp>
#include <MultiRegions/ContField.h>
#include <SpatialDomains/MeshGraphIO.h>

using namespace std;
using namespace Nektar;

int NoCaseStringCompare(const string &s1, const string &s2);

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

    LibUtilities::CommSharedPtr vComm = vSession->GetComm();
    MultiRegions::ContFieldSharedPtr Exp, Fce;
    int i, nq, coordim;
    Array<OneD, NekDouble> fce;
    Array<OneD, NekDouble> xc0, xc1, xc2;
    StdRegions::ConstFactorMap factors;

    if (argc < 2)
    {
        fprintf(stderr, "Usage: Helmholtz1D  meshfile \n");
        exit(1);
    }

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

        //----------------------------------------------
        // Read in mesh from input file
        SpatialDomains::MeshGraphSharedPtr graph1D =
            SpatialDomains::MeshGraphIO::Read(vSession);
        //----------------------------------------------

        //----------------------------------------------
        // Print summary of solution details
        factors[StdRegions::eFactorLambda] = vSession->GetParameter("Lambda");
        const SpatialDomains::ExpansionInfoMap &expansions =
            graph1D->GetExpansionInfo();
        LibUtilities::BasisKey bkey0 =
            expansions.begin()->second->m_basisKeyVector[0];

        if (vComm->GetRank() == 0)
        {
            cout << "Solving 1D Helmholtz: " << endl;
            cout << "       Communication: " << vComm->GetType() << endl;
            cout << "       Solver type  : "
                 << vSession->GetSolverInfo("GlobalSysSoln") << endl;
            cout << "       Lambda       : "
                 << factors[StdRegions::eFactorLambda] << endl;
            cout << "       No. modes    : " << bkey0.GetNumModes() << endl;
        }
        //----------------------------------------------

        //----------------------------------------------
        // Define Expansion
        Exp = MemoryManager<MultiRegions::ContField>::AllocateSharedPtr(
            vSession, graph1D, vSession->GetVariable(0));
        //----------------------------------------------

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

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

        switch (coordim)
        {
            case 1:
                Exp->GetCoords(xc0);
                Vmath::Zero(nq, &xc1[0], 1);
                Vmath::Zero(nq, &xc2[0], 1);
                break;
            case 2:
                Exp->GetCoords(xc0, xc1);
                Vmath::Zero(nq, &xc2[0], 1);
                break;
            case 3:
                Exp->GetCoords(xc0, xc1, xc2);
                break;
        }
        //----------------------------------------------

        //----------------------------------------------
        // 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);
        //----------------------------------------------

        //----------------------------------------------
        // 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);
        //----------------------------------------------

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

        //----------------------------------------------
        // Write solution
        string out(strtok(argv[1], "."));
        string endfile(".fld");
        out += endfile;
        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);
            //----------------------------------------------

            //--------------------------------------------
            // 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 (vComm->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 &)
    {
        cerr << "Caught exception." << endl;
        return 1;
    }

    vComm->Finalise();

    return 0;
}

/**
 * Performs a case-insensitive string comparison (from web).
 * @param   s1          First string to compare.
 * @param   s2          Second string to compare.
 * @returns             0 if the strings match.
 */
/*
int NoCaseStringCompare(const string & s1, const string& s2)
{
    string::const_iterator it1=s1.begin();
    string::const_iterator it2=s2.begin();

    //stop when either string's end has been reached
    while ( (it1!=s1.end()) && (it2!=s2.end()) )
    {
        if(::toupper(*it1) != ::toupper(*it2)) //letters differ?
        {
            // return -1 to indicate smaller than, 1 otherwise
            return (::toupper(*it1)  < ::toupper(*it2)) ? -1 : 1;
        }

        //proceed to the next character in each string
        ++it1;
        ++it2;
    }

    size_t size1=s1.size();
    size_t size2=s2.size();// cache lengths

    //return -1,0 or 1 according to strings' lengths
    if (size1==size2)
    {
        return 0;
    }

    return (size1 < size2) ? -1 : 1;
}

*/
