/*
Copyright 2017 TNO - Heat Transfer & Fluid Dynamics, Modelling & Optimization of the Subsurface
Copyright 2017 Statoil ASA.

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 3 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/>.
*/

#ifndef OPM_AQUIFETP_HEADER_INCLUDED
#define OPM_AQUIFETP_HEADER_INCLUDED

#include <opm/simulators/aquifers/AquiferInterface.hpp>

#include <opm/output/data/Aquifer.hpp>

#include <exception>
#include <stdexcept>

namespace Opm
{

template <typename TypeTag>
class AquiferFetkovich : public AquiferInterface<TypeTag>
{

public:
    typedef AquiferInterface<TypeTag> Base;

    using typename Base::BlackoilIndices;
    using typename Base::ElementContext;
    using typename Base::Eval;
    using typename Base::FluidState;
    using typename Base::FluidSystem;
    using typename Base::IntensiveQuantities;
    using typename Base::RateVector;
    using typename Base::Scalar;
    using typename Base::Simulator;

    using Base::waterCompIdx;
    using Base::waterPhaseIdx;

    AquiferFetkovich(const Aquancon::AquanconOutput& connection,
                     const std::unordered_map<int, int>& cartesian_to_compressed,
                     const Simulator& ebosSimulator,
                     const Aquifetp::AQUFETP_data& aqufetp_data)
        : Base(connection, cartesian_to_compressed, ebosSimulator)
        , aqufetp_data_(aqufetp_data)
    {
    }

    void endTimeStep() override
    {
        for (const auto& Qai : Base::Qai_) {
            Base::W_flux_ += Qai * Base::ebos_simulator_.timeStepSize();
            aquifer_pressure_ = aquiferPressure();
        }
    }

protected:
    // Aquifer Fetkovich Specific Variables
    // TODO: using const reference here will cause segmentation fault, which is very strange
    const Aquifetp::AQUFETP_data aqufetp_data_;
    Scalar aquifer_pressure_; // aquifer

    inline void initializeConnections() override
    {
        const auto& eclState = Base::ebos_simulator_.vanguard().eclState();
        const auto& ugrid = Base::ebos_simulator_.vanguard().grid();
        const auto& grid = eclState.getInputGrid();

        Base::cell_idx_ = this->connection_.global_index;
        auto globalCellIdx = ugrid.globalCell();


        // We hack the cell depth values for now. We can actually get it from elementcontext pos
        Base::cell_depth_.resize(Base::cell_idx_.size(), aqufetp_data_.d0);
        Base::alphai_.resize(Base::cell_idx_.size(), 1.0);
        Base::faceArea_connected_.resize(Base::cell_idx_.size(), 0.0);

        auto cell2Faces = Opm::UgGridHelpers::cell2Faces(ugrid);
        auto faceCells = Opm::UgGridHelpers::faceCells(ugrid);

        // Translate the C face tag into the enum used by opm-parser's TransMult class
        Opm::FaceDir::DirEnum faceDirection;

        // denom_face_areas is the sum of the areas connected to an aquifer
        Scalar denom_face_areas = 0.;
        Base::cellToConnectionIdx_.resize(Base::ebos_simulator_.gridView().size(/*codim=*/0), -1);
        for (size_t idx = 0; idx < Base::cell_idx_.size(); ++idx) {
            const int cell_index = Base::cartesian_to_compressed_.at(Base::cell_idx_[idx]);
            Base::cellToConnectionIdx_[cell_index] = idx;
            const auto cellCenter = grid.getCellCenter(Base::cell_idx_.at(idx));
            Base::cell_depth_.at(idx) = cellCenter[2];

            if (!this->connection_.influx_coeff[idx]) { // influx_coeff is defaulted
                const auto cellFacesRange = cell2Faces[cell_index];
                for (auto cellFaceIter = cellFacesRange.begin(); cellFaceIter != cellFacesRange.end(); ++cellFaceIter) {
                    // The index of the face in the compressed grid
                    const int faceIdx = *cellFaceIter;

                    // the logically-Cartesian direction of the face
                    const int faceTag = Opm::UgGridHelpers::faceTag(ugrid, cellFaceIter);

                    switch (faceTag) {
                    case 0:
                        faceDirection = Opm::FaceDir::XMinus;
                        break;
                    case 1:
                        faceDirection = Opm::FaceDir::XPlus;
                        break;
                    case 2:
                        faceDirection = Opm::FaceDir::YMinus;
                        break;
                    case 3:
                        faceDirection = Opm::FaceDir::YPlus;
                        break;
                    case 4:
                        faceDirection = Opm::FaceDir::ZMinus;
                        break;
                    case 5:
                        faceDirection = Opm::FaceDir::ZPlus;
                        break;
                    default:
                        OPM_THROW(Opm::NumericalIssue,
                                  "Initialization of Aquifer problem. Make sure faceTag is correctly defined");
                    }

                    if (faceDirection == this->connection_.reservoir_face_dir.at(idx)) {
                        Base::faceArea_connected_.at(idx)
                            = Base::getFaceArea(faceCells, ugrid, faceIdx, idx);
                        break;
                    }
                }
            } else {
                Base::faceArea_connected_.at(idx) = *this->connection_.influx_coeff[idx];
            }
            denom_face_areas += (this->connection_.influx_multiplier.at(idx) * Base::faceArea_connected_.at(idx));
        }

        const double eps_sqrt = std::sqrt(std::numeric_limits<double>::epsilon());
        for (size_t idx = 0; idx < Base::cell_idx_.size(); ++idx) {
            Base::alphai_.at(idx) = (denom_face_areas < eps_sqrt)
                ? // Prevent no connection NaNs due to division by zero
                0.
                : (this->connection_.influx_multiplier.at(idx) * Base::faceArea_connected_.at(idx)) / denom_face_areas;
        }
    }

    void assignRestartData(const data::AquiferData& xaq) override
    {
        if (xaq.type != data::AquiferType::Fetkovich) {
            throw std::invalid_argument {"Analytic aquifer data for unexpected aquifer type "
                                         "passed to Fetkovich aquifer"};
        }

        this->aquifer_pressure_ = xaq.pressure;
    }

    inline Eval dpai(int idx)
    {
        const Eval dp = aquifer_pressure_ - Base::pressure_current_.at(idx)
            + Base::rhow_[idx] * Base::gravity_() * (Base::cell_depth_[idx] - aqufetp_data_.d0);
        return dp;
    }

    // This function implements Eq 5.12 of the EclipseTechnicalDescription
    inline Scalar aquiferPressure()
    {
        Scalar Flux = Base::W_flux_.value();
        Scalar pa_ = Base::pa0_ - Flux / (aqufetp_data_.C_t * aqufetp_data_.V0);
        return pa_;
    }

    inline void calculateAquiferConstants() override
    {
        Base::Tc_ = (aqufetp_data_.C_t * aqufetp_data_.V0) / aqufetp_data_.J;
    }
    // This function implements Eq 5.14 of the EclipseTechnicalDescription
    inline void calculateInflowRate(int idx, const Simulator& simulator) override
    {
        const Scalar td_Tc_ = simulator.timeStepSize() / Base::Tc_;
        const Scalar coef = (1 - exp(-td_Tc_)) / td_Tc_;
        Base::Qai_.at(idx) = Base::alphai_[idx] * aqufetp_data_.J * dpai(idx) * coef;
    }

    inline void calculateAquiferCondition() override
    {
        Base::rhow_.resize(Base::cell_idx_.size(), 0.);

        if (this->solution_set_from_restart_) {
            return;
        }

        if (!aqufetp_data_.p0.first) {
            Base::pa0_ = calculateReservoirEquilibrium();
        } else {
            Base::pa0_ = aqufetp_data_.p0.second;
        }
        aquifer_pressure_ = Base::pa0_;
    }

    inline Scalar calculateReservoirEquilibrium() override
    {
        // Since the global_indices are the reservoir index, we just need to extract the fluidstate at those indices
        std::vector<Scalar> pw_aquifer;
        Scalar water_pressure_reservoir;

        ElementContext elemCtx(Base::ebos_simulator_);
        const auto& gridView = Base::ebos_simulator_.gridView();
        auto elemIt = gridView.template begin</*codim=*/0>();
        const auto& elemEndIt = gridView.template end</*codim=*/0>();
        for (; elemIt != elemEndIt; ++elemIt) {
            const auto& elem = *elemIt;
            elemCtx.updatePrimaryStencil(elem);
            size_t cellIdx = elemCtx.globalSpaceIndex(/*spaceIdx=*/0, /*timeIdx=*/0);
            int idx = Base::cellToConnectionIdx_[cellIdx];
            if (idx < 0)
                continue;

            elemCtx.updatePrimaryIntensiveQuantities(/*timeIdx=*/0);
            const auto& iq0 = elemCtx.intensiveQuantities(/*spaceIdx=*/0, /*timeIdx=*/0);
            const auto& fs = iq0.fluidState();

            water_pressure_reservoir = fs.pressure(waterPhaseIdx).value();
            Base::rhow_[idx] = fs.density(waterPhaseIdx);
            pw_aquifer.push_back(
                (water_pressure_reservoir
                 - Base::rhow_[idx].value() * Base::gravity_() * (Base::cell_depth_[idx] - aqufetp_data_.d0))
                * Base::alphai_[idx]);
        }

        // We take the average of the calculated equilibrium pressures.
        const Scalar sum_alpha = std::accumulate(this->alphai_.begin(), this->alphai_.end(), 0.);
        const Scalar aquifer_pres_avg = std::accumulate(pw_aquifer.begin(), pw_aquifer.end(), 0.) / sum_alpha;
        return aquifer_pres_avg;
    }
}; // Class AquiferFetkovich
} // namespace Opm
#endif