// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*
  This file is part of the Open Porous Media project (OPM).

  OPM is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 2 of the License, or
  (at your option) any later version.

  OPM is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with OPM.  If not, see <http://www.gnu.org/licenses/>.

  Consult the COPYING file in the top-level source directory of this
  module for the precise wording of the license and the list of
  copyright holders.
*/
/**
 * \file
 *
 * \copydoc Ewoms::EclEquilInitializer
 */
#ifndef EWOMS_ECL_EQUIL_INITIALIZER_HH
#define EWOMS_ECL_EQUIL_INITIALIZER_HH

#include <ewoms/common/propertysystem.hh>

#include <opm/material/fluidstates/CompositionalFluidState.hpp>

// the ordering of these includes matters. do not touch it if you're not prepared to deal
// with some trouble!
#include <dune/grid/cpgrid/GridHelpers.hpp>
#include <opm/core/props/BlackoilPropertiesFromDeck.hpp>
#include <opm/core/simulator/initStateEquil.hpp>
#include <opm/core/simulator/BlackoilState.hpp>

#include <vector>

namespace Ewoms {
namespace Properties {
NEW_PROP_TAG(Simulator);
NEW_PROP_TAG(FluidSystem);
NEW_PROP_TAG(GridView);
NEW_PROP_TAG(Scalar);
NEW_PROP_TAG(MaterialLaw);
NEW_PROP_TAG(EnableSwatinit);
}

/*!
 * \ingroup EclBlackOilSimulator
 *
 * \brief Computes the initial condition based on the EQUIL keyword from ECL.
 *
 * So far, it uses the "initStateEquil()" function from opm-core. Since this method is
 * very much glued into the opm-core data structures, it should be reimplemented in the
 * medium to long term for some significant memory savings and less significant
 * performance improvements.
 */
template <class TypeTag>
class EclEquilInitializer
{
    typedef typename GET_PROP_TYPE(TypeTag, Simulator) Simulator;
    typedef typename GET_PROP_TYPE(TypeTag, FluidSystem) FluidSystem;
    typedef typename GET_PROP_TYPE(TypeTag, GridView) GridView;
    typedef typename GET_PROP_TYPE(TypeTag, Scalar) Scalar;
    typedef typename GET_PROP_TYPE(TypeTag, MaterialLaw) MaterialLaw;

    typedef Opm::CompositionalFluidState<Scalar, FluidSystem> ScalarFluidState;

    enum { numPhases = FluidSystem::numPhases };
    enum { oilPhaseIdx = FluidSystem::oilPhaseIdx };
    enum { gasPhaseIdx = FluidSystem::gasPhaseIdx };
    enum { waterPhaseIdx = FluidSystem::waterPhaseIdx };

    enum { numComponents = FluidSystem::numComponents };
    enum { oilCompIdx = FluidSystem::oilCompIdx };
    enum { gasCompIdx = FluidSystem::gasCompIdx };
    enum { waterCompIdx = FluidSystem::waterCompIdx };

    enum { dimWorld = GridView::dimensionworld };

public:
    template <class MaterialLawManager>
    EclEquilInitializer(const Simulator& simulator,
                        std::shared_ptr<MaterialLawManager> materialLawManager)
        : simulator_(simulator)
    {
        const auto& gridManager = simulator.gridManager();
        const auto deck = gridManager.deck();
        const auto eclState = gridManager.eclState();
        const auto& equilGrid   = gridManager.equilGrid();

        unsigned numElems = gridManager.grid().size(0);
        unsigned numEquilElems = gridManager.equilGrid().size(0);
        unsigned numCartesianElems = gridManager.cartesianSize();
        typedef typename GET_PROP_TYPE(TypeTag, FluidSystem) FluidSystem;
        typedef Opm::ThreePhaseMaterialTraits<double,
                                              /*wettingPhaseIdx=*/FluidSystem::waterPhaseIdx,
                                              /*nonWettingPhaseIdx=*/FluidSystem::oilPhaseIdx,
                                              /*gasPhaseIdx=*/FluidSystem::gasPhaseIdx> EquilTraits;

        // create a separate instance of the material law manager just because opm-core
        // only supports double as the type for scalars (but ebos may use float or quad)
        std::vector<int> compressedToCartesianEquilElemIdx(numEquilElems);
        for (unsigned equilElemIdx = 0; equilElemIdx < numEquilElems; ++equilElemIdx)
            compressedToCartesianEquilElemIdx[equilElemIdx] = gridManager.equilCartesianIndex(equilElemIdx);

        auto equilMaterialLawManager =
            std::make_shared<Opm::EclMaterialLawManager<EquilTraits> >();
        equilMaterialLawManager->initFromDeck(*deck, *eclState, compressedToCartesianEquilElemIdx);

        // create the data structures which are used by initStateEquil()
        Opm::parameter::ParameterGroup tmpParam;
        Opm::BlackoilPropertiesFromDeck opmBlackoilProps(
            *gridManager.deck(),
            *gridManager.eclState(),
            equilMaterialLawManager,
            Opm::UgGridHelpers::numCells(equilGrid),
            Opm::UgGridHelpers::globalCell(equilGrid),
            Opm::UgGridHelpers::cartDims(equilGrid),
            tmpParam);

        assert( gridManager.grid().size(/*codim=*/0) == static_cast<int>(numEquilElems) );
        // initialize the boiler plate of opm-core the state structure.
        const auto opmPhaseUsage = opmBlackoilProps.phaseUsage();
        Opm::BlackoilState opmBlackoilState(numEquilElems,
                                            /*numFaces=*/0, // we don't care here
                                            opmPhaseUsage.num_phases);

        // do the actual computation.
        Opm::initStateEquil(equilGrid,
                            opmBlackoilProps,
                            *gridManager.deck(),
                            *gridManager.eclState(),
                            simulator.problem().gravity()[dimWorld - 1],
                            opmBlackoilState);

        // copy the result into the array of initial fluid states
        initialFluidStates_.resize(numCartesianElems);
        for (unsigned equilElemIdx = 0; equilElemIdx < numEquilElems; ++equilElemIdx) {
            unsigned cartesianElemIdx = gridManager.equilCartesianIndex(equilElemIdx);
            auto& fluidState = initialFluidStates_[cartesianElemIdx];

            // get the PVT region index of the current element
            unsigned regionIdx = simulator_.problem().pvtRegionIndex(equilElemIdx);

            // set the phase saturations
            for (unsigned phaseIdx = 0; phaseIdx < numPhases; ++phaseIdx) {
                Scalar S;
                if (!FluidSystem::phaseIsActive(phaseIdx))
                    S = 0.0;
                else {
                    unsigned opmPhasePos = 10000;
                    switch (phaseIdx) {
                    case oilPhaseIdx:
                        opmPhasePos = opmPhaseUsage.phase_pos[Opm::BlackoilPhases::Liquid];
                        break;

                    case gasPhaseIdx:
                        opmPhasePos = opmPhaseUsage.phase_pos[Opm::BlackoilPhases::Vapour];
                        break;

                    case waterPhaseIdx:
                        opmPhasePos = opmPhaseUsage.phase_pos[Opm::BlackoilPhases::Aqua];
                        break;
                    }
                    S = opmBlackoilState.saturation()[equilElemIdx*opmPhaseUsage.num_phases
                                                      + opmPhasePos];
                }
                fluidState.setSaturation(phaseIdx, S);
            }

            // set the temperature
            const auto& temperatureVector = opmBlackoilState.temperature();
            Scalar T = FluidSystem::surfaceTemperature;
            if (!temperatureVector.empty())
                T = temperatureVector[equilElemIdx];
            fluidState.setTemperature(T);

            // set the phase pressures. the Opm::BlackoilState only provides the oil
            // phase pressure, so we need to calculate the other phases' pressures
            // ourselfs.
            Dune::FieldVector< Scalar, numPhases >  pC( 0 );
            const auto& matParams = simulator.problem().materialLawParams(equilElemIdx);
            MaterialLaw::capillaryPressures(pC, matParams, fluidState);
            Scalar po = opmBlackoilState.pressure()[equilElemIdx];
            for (unsigned phaseIdx = 0; phaseIdx < numPhases; ++phaseIdx)
                fluidState.setPressure(phaseIdx, po + (pC[phaseIdx] - pC[oilPhaseIdx]));

            // reset the phase compositions
            for (unsigned phaseIdx = 0; phaseIdx < numPhases; ++phaseIdx)
                for (unsigned compIdx = 0; compIdx < numComponents; ++compIdx)
                    fluidState.setMoleFraction(phaseIdx, compIdx, 0.0);

            // the composition of the water phase is simple: it only consists of the
            // water component.
            fluidState.setMoleFraction(waterPhaseIdx, waterCompIdx, 1.0);

            if (FluidSystem::enableDissolvedGas()) {
                // for gas and oil we have to translate surface volumes to mole fractions
                // before we can set the composition in the fluid state
                Scalar Rs = opmBlackoilState.gasoilratio()[equilElemIdx];
                Scalar RsSat = FluidSystem::saturatedDissolutionFactor(fluidState, oilPhaseIdx, regionIdx);

                if (Rs > RsSat)
                    Rs = RsSat;

                // convert the Rs factor to mole fraction dissolved gas in oil
                Scalar XoG = FluidSystem::convertRsToXoG(Rs, regionIdx);
                Scalar xoG = FluidSystem::convertXoGToxoG(XoG, regionIdx);

                fluidState.setMoleFraction(oilPhaseIdx, oilCompIdx, 1 - xoG);
                fluidState.setMoleFraction(oilPhaseIdx, gasCompIdx, xoG);
            }

            // retrieve the surface volume of vaporized gas
            if (FluidSystem::enableVaporizedOil()) {
                Scalar Rv = opmBlackoilState.rv()[equilElemIdx];
                Scalar RvSat = FluidSystem::saturatedDissolutionFactor(fluidState, gasPhaseIdx, regionIdx);

                if (Rv > RvSat)
                    Rv = RvSat;

                // convert the Rs factor to mole fraction dissolved gas in oil
                Scalar XgO = FluidSystem::convertRvToXgO(Rv, regionIdx);
                Scalar xgO = FluidSystem::convertXgOToxgO(XgO, regionIdx);

                fluidState.setMoleFraction(gasPhaseIdx, oilCompIdx, xgO);
                fluidState.setMoleFraction(gasPhaseIdx, gasCompIdx, 1 - xgO);
            }
        }

        // deal with the capillary pressure modification due to SWATINIT. this is
        // only necessary because, the fine equilibration code from opm-core requires
        // its own grid and its own material law manager...
        std::vector<int> cartesianToCompressedElemIdx(numCartesianElems, -1);
        for (unsigned elemIdx = 0; elemIdx < numElems; ++elemIdx) {
            int cartElemIdx = gridManager.cartesianIndex(elemIdx);
            cartesianToCompressedElemIdx[cartElemIdx] = elemIdx;
        }

        if (GET_PROP_VALUE(TypeTag, EnableSwatinit)) {
            for (unsigned equilElemIdx = 0; equilElemIdx < numEquilElems; ++equilElemIdx) {
                int cartElemIdx = gridManager.equilCartesianIndex(equilElemIdx);
                assert(cartElemIdx >= 0);
                int elemIdx = cartesianToCompressedElemIdx[cartElemIdx];
                if (elemIdx < 0)
                    // the element is present in the grid for used for equilibration but
                    // it isn't present in the one used for the simulation. the most
                    // probable reason for this is that the simulation grid was load
                    // balanced.
                    continue;

                auto& scalingPoints = materialLawManager->oilWaterScaledEpsPointsDrainage(equilElemIdx);
                const auto& equilScalingPoints = equilMaterialLawManager->oilWaterScaledEpsPointsDrainage(equilElemIdx);

                scalingPoints.setMaxPcnw(equilScalingPoints.maxPcnw());
            }
        }
    }

    /*!
     * \brief Return the initial thermodynamic state which should be used as the initial
     *        condition.
     *
     * This is supposed to correspond to hydrostatic conditions.
     */
    const ScalarFluidState& initialFluidState(unsigned elemIdx) const
    {
        const auto& gridManager = simulator_.gridManager();

        unsigned cartesianElemIdx = gridManager.cartesianIndex(elemIdx);
        return initialFluidStates_[cartesianElemIdx];
    }

protected:
    const Simulator& simulator_;

    std::vector<ScalarFluidState> initialFluidStates_;
};
} // namespace Ewoms

#endif