// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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/*!
 * \file
 * \brief The main file for the 2p2c porousmediumflow problem in exercise-basic
 */
#include <config.h>

#include <ctime>
#include <iostream>

#include <dune/common/parallel/mpihelper.hh>
#include <dune/common/timer.hh>
#include <dune/grid/io/file/dgfparser/dgfexception.hh>
#include <dune/grid/io/file/vtk.hh>

#include <dumux/common/properties.hh>
#include <dumux/common/parameters.hh>
#include <dumux/common/valgrind.hh>
#include <dumux/common/dumuxmessage.hh>

#include <dumux/linear/amgbackend.hh>
#include <dumux/nonlinear/newtonsolver.hh>

#include <dumux/assembly/fvassembler.hh>
#include <dumux/assembly/diffmethod.hh>

#include <dumux/discretization/method.hh>

#include <dumux/io/vtkoutputmodule.hh>
#include <dumux/io/grid/gridmanager.hh>
#include <dumux/io/loadsolution.hh>

// The problem file, where setup-specific boundary and initial conditions are defined.
#include "injection2p2cproblem.hh"

////////////////////////
// the main function
////////////////////////
int main(int argc, char** argv) try
{
    using namespace Dumux;

    // define the type tag for this problem
    using TypeTag = Properties::TTag::Injection2p2cCCTypeTag;

    // initialize MPI, finalize is done automatically on exit
    const auto& mpiHelper = Dune::MPIHelper::instance(argc, argv);

    // print dumux start message
    if (mpiHelper.rank() == 0)
        DumuxMessage::print(/*firstCall=*/true);

    // parse command line arguments and input file
    Parameters::init(argc, argv);

    // try to create a grid (from the given grid file or the input file)
    GridManager<GetPropType<TypeTag, Properties::Grid>> gridManager;
    gridManager.init();

    ////////////////////////////////////////////////////////////
    // run instationary non-linear problem on this grid
    ////////////////////////////////////////////////////////////

    // we compute on the leaf grid view
    const auto& leafGridView = gridManager.grid().leafGridView();

    // create the finite volume grid geometry
    using FVGridGeometry = GetPropType<TypeTag, Properties::FVGridGeometry>;
    auto fvGridGeometry = std::make_shared<FVGridGeometry>(leafGridView);
    fvGridGeometry->update();

    // the problem (initial and boundary conditions)
    using Problem = GetPropType<TypeTag, Properties::Problem>;
    auto problem = std::make_shared<Problem>(fvGridGeometry);

    // check if we are about to restart a previously interrupted simulation
    using Scalar = GetPropType<TypeTag, Properties::Scalar>;
    Scalar restartTime = getParam<Scalar>("Restart.Time", 0);

    // the solution vector
    using SolutionVector = GetPropType<TypeTag, Properties::SolutionVector>;
    SolutionVector x(fvGridGeometry->numDofs());
//     problem->applyInitialSolution(x);
        if (restartTime > 0)
    {
        using IOFields = GetPropType<TypeTag, Properties::IOFields>;
        using PrimaryVariables = GetPropType<TypeTag, Properties::PrimaryVariables>;
        using ModelTraits = GetPropType<TypeTag, Properties::ModelTraits>;
        using FluidSystem = GetPropType<TypeTag, Properties::FluidSystem>;
        const auto fileName = getParam<std::string>("Restart.File");
        const auto pvName = createPVNameFunction<IOFields, PrimaryVariables, ModelTraits, FluidSystem>();
        loadSolution(x, fileName, pvName, *fvGridGeometry);
    }
    else
        problem->applyInitialSolution(x);
    auto xOld = x;

    // the grid variables
    using GridVariables = GetPropType<TypeTag, Properties::GridVariables>;
    auto gridVariables = std::make_shared<GridVariables>(problem, fvGridGeometry);
    gridVariables->init(x);

    // get some time loop parameters
    using Scalar = GetPropType<TypeTag, Properties::Scalar>;
    const auto tEnd = getParam<Scalar>("TimeLoop.TEnd");
    const auto maxDt = getParam<Scalar>("TimeLoop.MaxTimeStepSize");
    auto dt = getParam<Scalar>("TimeLoop.DtInitial");

    // intialize the vtk output module
//     using VtkOutputFields = GetPropType<TypeTag, Properties::VtkOutputFields>;
//     VtkOutputModule<TypeTag> vtkWriter(*problem, *fvGridGeometry, *gridVariables, x, problem->name());
//     VtkOutputFields::init(vtkWriter); //! Add model specific output fields

    // intialize the vtk output module
    using VtkOutputFields = GetPropType<TypeTag, Properties::VtkOutputFields>;
    VtkOutputModule<GridVariables, SolutionVector> vtkWriter(*gridVariables, x, problem->name());
    using VelocityOutput = GetPropType<TypeTag, Properties::VelocityOutput>;
    vtkWriter.addVelocityOutput(std::make_shared<VelocityOutput>(*gridVariables));
    VtkOutputFields::initOutputModule(vtkWriter); //!< Add model specific output fields
    vtkWriter.write(restartTime);

    // instantiate time loop
    auto timeLoop = std::make_shared<TimeLoop<Scalar>>(restartTime, dt, tEnd);
    timeLoop->setMaxTimeStepSize(maxDt);

    // the assembler with time loop for instationary problem
    using Assembler = FVAssembler<TypeTag, DiffMethod::numeric>;
    auto assembler = std::make_shared<Assembler>(problem, fvGridGeometry, gridVariables, timeLoop);

    // the linear solver
    using LinearSolver = AMGBackend<TypeTag>;
    auto linearSolver = std::make_shared<LinearSolver>(leafGridView, fvGridGeometry->dofMapper());

    // the non-linear solver
//     using PrimaryVariableSwitch = GetPropType<TypeTag, Properties::PrimaryVariableSwitch>;
    using NewtonSolver = NewtonSolver<Assembler, LinearSolver>;
    NewtonSolver nonLinearSolver(assembler, linearSolver);

    // time loop
    timeLoop->start();
    while (!timeLoop->finished())
    {
        // set previous solution for storage evaluations
        assembler->setPreviousSolution(xOld);

        //set time in problem (is used in time-dependent Neumann boundary condition)
        problem->setTime(timeLoop->time()+timeLoop->timeStepSize());

        // solve the non-linear system with time step control
        nonLinearSolver.solve(x, *timeLoop);

        // make the new solution the old solution
        xOld = x;
        gridVariables->advanceTimeStep();

        // advance to the time loop to the next step
        timeLoop->advanceTimeStep();

        // report statistics of this time step
        timeLoop->reportTimeStep();

        // set new dt as suggested by the newton solver
        timeLoop->setTimeStepSize(nonLinearSolver.suggestTimeStepSize(timeLoop->timeStepSize()));

        // output to vtk
        vtkWriter.write(timeLoop->time());
    }

    timeLoop->finalize(leafGridView.comm());

    ////////////////////////////////////////////////////////////
    // finalize, print dumux message to say goodbye
    ////////////////////////////////////////////////////////////

    // print dumux end message
    if (mpiHelper.rank() == 0)
    {
        Parameters::print();
        DumuxMessage::print(/*firstCall=*/false);
    }

    return 0;
} // end main
catch (Dumux::ParameterException &e)
{
    std::cerr << std::endl << e << " ---> Abort!" << std::endl;
    return 1;
}
catch (Dune::DGFException & e)
{
    std::cerr << "DGF exception thrown (" << e <<
                 "). Most likely, the DGF file name is wrong "
                 "or the DGF file is corrupted, "
                 "e.g. missing hash at end of file or wrong number (dimensions) of entries."
                 << " ---> Abort!" << std::endl;
    return 2;
}
catch (Dune::Exception &e)
{
    std::cerr << "Dune reported error: " << e << " ---> Abort!" << std::endl;
    return 3;
}
catch (...)
{
    std::cerr << "Unknown exception thrown! ---> Abort!" << std::endl;
    return 4;
}