/*
  Copyright 2014 SINTEF ICT, Applied Mathematics.

  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_WELLSTATEFULLYIMPLICITBLACKOIL_HEADER_INCLUDED
#define OPM_WELLSTATEFULLYIMPLICITBLACKOIL_HEADER_INCLUDED


#include <opm/core/wells.h>
#include <opm/core/well_controls.h>
#include <opm/core/simulator/WellState.hpp>
#include <opm/core/utility/ErrorMacros.hpp>
#include <vector>
#include <cassert>
#include <string>
#include <utility>
#include <map>
#include <algorithm>
#include <array>

namespace Opm
{

    /// The state of a set of wells, tailored for use by the fully
    /// implicit blackoil simulator.
    class WellStateFullyImplicitBlackoil
        : public WellState
    {
        typedef WellState  BaseType;
    public:
        typedef std::array< int, 3 >  mapentry_t;
        typedef std::map< std::string, mapentry_t > WellMapType;

        using BaseType :: wellRates;
        using BaseType :: bhp;
        using BaseType :: perfPress;

        /// Allocate and initialize if wells is non-null.  Also tries
        /// to give useful initial values to the bhp(), wellRates()
        /// and perfPhaseRates() fields, depending on controls
        template <class State, class PrevState>
        void init(const Wells* wells, const State& state, const PrevState& prevState)
        {
            // clear old name mapping
            wellMap_.clear();

            if (wells == 0) {
                return;
            }

            const int nw = wells->number_of_wells;
            if( nw == 0 ) return ;

            // We use the WellState::init() function to do bhp and well rates init.
            // The alternative would be to copy that function wholesale.
            BaseType :: init(wells, state);

            // Initialize perfphaserates_, which must be done here.
            const int np = wells->number_of_phases;
            const int nperf = wells->well_connpos[nw];
            // Ensure that we start out with zero rates by default.
            perfphaserates_.clear();
            perfphaserates_.resize(nperf * np, 0.0);
            for (int w = 0; w < nw; ++w) {
                assert((wells->type[w] == INJECTOR) || (wells->type[w] == PRODUCER));
                const WellControls* ctrl = wells->ctrls[w];
                std::string name( wells->name[ w ] );
                assert( name.size() > 0 );
                mapentry_t& wellMapEntry = wellMap_[name];
                wellMapEntry[ 0 ] = w;
                wellMapEntry[ 1 ] = wells->well_connpos[w];
                // also store the number of perforations in this well
                const int num_perf_this_well = wells->well_connpos[w + 1] - wells->well_connpos[w];
                wellMapEntry[ 2 ] = num_perf_this_well;

                if (well_controls_well_is_stopped(ctrl)) {
                    // Shut well: perfphaserates_ are all zero.
                } else {
                    // Open well: Initialize perfphaserates_ to well
                    // rates divided by the number of perforations.
                    for (int perf = wells->well_connpos[w]; perf < wells->well_connpos[w + 1]; ++perf) {
                        for (int p = 0; p < np; ++p) {
                            perfphaserates_[np*perf + p] = wellRates()[np*w + p] / double(num_perf_this_well);
                        }
                        perfPress()[perf] = state.pressure()[wells->well_cells[perf]];
                    }
                }
            }

            // Initialize current_controls_.
            // The controls set in the Wells object are treated as defaults,
            // and also used for initial values.
            current_controls_.resize(nw);
            for (int w = 0; w < nw; ++w) {
                current_controls_[w] = well_controls_get_current(wells->ctrls[w]);
            }

            // intialize wells that have been there before
            // order may change so the mapping is based on the well name
            if( ! prevState.wellMap().empty() )
            {
                typedef typename WellMapType :: const_iterator const_iterator;
                const_iterator end = prevState.wellMap().end();
                for (int w = 0; w < nw; ++w) {
                    std::string name( wells->name[ w ] );
                    const_iterator it = prevState.wellMap().find( name );
                    if( it != end )
                    {
                        const int oldIndex = (*it).second[ 0 ];
                        const int newIndex = w;

                        // bhp
                        bhp()[ newIndex ] = prevState.bhp()[ oldIndex ];

                        // wellrates
                        for( int i=0, idx=newIndex*np, oldidx=oldIndex*np; i<np; ++i, ++idx, ++oldidx )
                        {
                            wellRates()[ idx ] = prevState.wellRates()[ oldidx ];
                        }

                        // perfPhaseRates
                        int oldPerf_idx = (*it).second[ 1 ];
                        const int num_perf_old_well = (*it).second[ 2 ];
                        const int num_perf_this_well = wells->well_connpos[newIndex + 1] - wells->well_connpos[newIndex];
                        // copy perforation rates when the number of perforations is equal,
                        // otherwise initialize perfphaserates to well rates divided by the number of perforations.
                        if( num_perf_old_well == num_perf_this_well )
                        {
                            int oldPerf = oldPerf_idx *np;
                            for (int perf = wells->well_connpos[ newIndex ]*np;
                                 perf < wells->well_connpos[ newIndex + 1]*np; ++perf, ++oldPerf )
                            {
                                perfPhaseRates()[ perf ] = prevState.perfPhaseRates()[ oldPerf ];
                            }
                        } else {
                            for (int perf = wells->well_connpos[newIndex]; perf < wells->well_connpos[newIndex + 1]; ++perf) {
                                for (int p = 0; p < np; ++p) {
                                    perfPhaseRates()[np*perf + p] = wellRates()[np*newIndex + p] / double(num_perf_this_well);
                                }
                            }
                        }
                        // perfPressures
                        if( num_perf_old_well == num_perf_this_well )
                        {
                            for (int perf = wells->well_connpos[ newIndex ];
                                 perf < wells->well_connpos[ newIndex + 1]; ++perf, ++oldPerf_idx )
                            {
                                perfPress()[ perf ] = prevState.perfPress()[ oldPerf_idx ];
                            }
                        }

                        // currentControls
                        const int old_control_index = prevState.currentControls()[ oldIndex ];
                        if (old_control_index < well_controls_get_num(wells->ctrls[w])) {
                            // If the set of controls have changed, this may not be identical
                            // to the last control, but it must be a valid control.
                            currentControls()[ newIndex ] = old_control_index;
                        }

                    }
                }
            }
        }

        /// One rate per phase and well connection.
        std::vector<double>& perfPhaseRates() { return perfphaserates_; }
        const std::vector<double>& perfPhaseRates() const { return perfphaserates_; }

        /// One current control per well.
        std::vector<int>& currentControls() { return current_controls_; }
        const std::vector<int>& currentControls() const { return current_controls_; }

        /// The number of wells present.
        int numWells() const
        {
            return bhp().size();
        }

        /// The number of phases present.
        int numPhases() const
        {
            return wellRates().size() / numWells();
        }

        const WellMapType& wellMap() const { return wellMap_; }
        WellMapType& wellMap() { return wellMap_; }

    private:
        std::vector<double> perfphaserates_;
        std::vector<int> current_controls_;
        WellMapType wellMap_;
    };

} // namespace Opm


#endif // OPM_WELLSTATEFULLYIMPLICITBLACKOIL_HEADER_INCLUDED