// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
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/*!
 * \file
 * \ingroup OnePTests
 * \brief Test for the one-phase CC model
 */

#include <config.h>

#include <ctime>
#include <iostream>

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

#include "problem.hh"

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

#include <dumux/linear/amgbackend.hh>
#include <dumux/linear/linearsolvertraits.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>

/*!
 * \brief Provides an interface for customizing error messages associated with
 *        reading in parameters.
 *
 * \param progName  The name of the program, that was tried to be started.
 * \param errorMsg  The error message that was issued by the start function.
 *                  Comprises the thing that went wrong and a general help message.
 */
void usage(const char *progName, const std::string &errorMsg)
{
    if (errorMsg.size() > 0) {
        std::string errorMessageOut = "\nUsage: ";
                    errorMessageOut += progName;
                    errorMessageOut += " [options]\n";
                    errorMessageOut += errorMsg;
                    errorMessageOut += "\n\nThe list of mandatory arguments for this program is:\n"
                                        "\t-TimeManager.TEnd               End of the simulation [s] \n"
                                        "\t-TimeManager.DtInitial          Initial timestep size [s] \n"
                                        "\t-Grid.LowerLeft                 Lower left corner coordinates\n"
                                        "\t-Grid.UpperRight                Upper right corner coordinates\n"
                                        "\t-Grid.Cells                     Number of cells in respective coordinate directions\n"
                                        "\t-SpatialParams.LensLowerLeft   coordinates of the lower left corner of the lens [m] \n"
                                        "\t-SpatialParams.LensUpperRight  coordinates of the upper right corner of the lens [m] \n"
                                        "\t-SpatialParams.Permeability     Permeability of the domain [m^2] \n"
                                        "\t-SpatialParams.PermeabilityLens Permeability of the lens [m^2] \n";

        std::cout << errorMessageOut
                  << "\n";
    }
}

int main(int argc, char** argv)
{
    using namespace Dumux;

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

    // 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, usage);

    // 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 GridGeometry = GetPropType<TypeTag, Properties::GridGeometry>;
    auto gridGeometry = std::make_shared<GridGeometry>(leafGridView);
    gridGeometry->update();

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

    // the solution vector
    using SolutionVector = GetPropType<TypeTag, Properties::SolutionVector>;
    SolutionVector x(gridGeometry->numDofs());
    problem->applyInitialSolution(x);
    auto xOld = x;

    // the grid variables
    using GridVariables = GetPropType<TypeTag, Properties::GridVariables>;
    auto gridVariables = std::make_shared<GridVariables>(problem, gridGeometry);
    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 IOFields = GetPropType<TypeTag, Properties::IOFields>;
    VtkOutputModule<GridVariables, SolutionVector> vtkWriter(*gridVariables, x, problem->name());
    using VelocityOutput = GetPropType<TypeTag, Properties::VelocityOutput>;
    vtkWriter.addVelocityOutput(std::make_shared<VelocityOutput>(*gridVariables));
    IOFields::initOutputModule(vtkWriter); // Add model specific output fields

    // if we are using a random permeability field with gstat
    bool isRandomField = getParam<bool>("SpatialParams.RandomField", false);
    if(isRandomField) vtkWriter.addField(problem->spatialParams().getPermField(), "K");

    vtkWriter.write(0.0);

    // instantiate time loop
    auto timeLoop = std::make_shared<TimeLoop<Scalar>>(0, 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, gridGeometry, gridVariables, timeLoop, xOld);

    // the linear solver
    using LinearSolver = AMGBiCGSTABBackend<LinearSolverTraits<GridGeometry>>;
    auto linearSolver = std::make_shared<LinearSolver>(leafGridView, gridGeometry->dofMapper());

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

    // time loop
    timeLoop->start(); do
    {
        // linearize & solve
        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();

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

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

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

    } while (!timeLoop->finished());

    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
