/*
  Copyright 2020 OPM-OP AS

  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/>.
*/
#include <config.h>
#include <opm/simulators/wells/ParallelWellInfo.hpp>
#include <opm/common/ErrorMacros.hpp>

namespace Dune
{
#if HAVE_MPI
template<>
struct CommPolicy<double*>
{
    using Type = double*;
    using IndexedType = double;
    using IndexedTypeFlag = Dune::SizeOne;
    static const void* getAddress(const double*& v, int index)
    {
        return v + index;
    }
    static int getSize(const double*&, int)
    {
        return 1;
    }
};
#endif
}

namespace Opm
{
CommunicateAboveBelow::CommunicateAboveBelow([[maybe_unused]] const Communication& comm)
#if HAVE_MPI
    : comm_(comm), interface_(comm_)
#endif
{}

void CommunicateAboveBelow::clear()
{
#if HAVE_MPI
    above_indices_ = {};
    current_indices_ = {};
    interface_.free();
    communicator_.free();
#endif
    count_ = 0;
}

void CommunicateAboveBelow::beginReset()
{
    clear();
#if HAVE_MPI
    if (comm_.size() > 1)
    {
        current_indices_.beginResize();
        above_indices_.beginResize();
    }
#endif
}

void CommunicateAboveBelow::endReset()
{
#if HAVE_MPI
    if (comm_.size() > 1)
    {
        above_indices_.endResize();
        current_indices_.endResize();
        remote_indices_.setIndexSets(current_indices_, above_indices_, comm_);
        remote_indices_.setIncludeSelf(true);
        remote_indices_.rebuild<true>();
        using FromSet = Dune::EnumItem<Attribute,owner>;
        using ToSet = Dune::AllSet<Attribute>;
        interface_.build(remote_indices_, FromSet(), ToSet());
        communicator_.build<double*>(interface_);
    }
#endif
}

struct CopyGatherScatter
{
    static const double& gather(const double* a, std::size_t i)
    {
        return a[i];
    }

    static void scatter(double* a, const double& v, std::size_t i)
    {
        a[i] = v;
    }
};


std::vector<double> CommunicateAboveBelow::communicateAbove(double first_above,
                                                            const double* current,
                                                            std::size_t size)
{
    std::vector<double> above(size, first_above);

#if HAVE_MPI
    if (comm_.size() > 1)
    {
        auto aboveData = above.data();
        // Ugly const_cast needed as my compiler says, that
        // passing const double*& and double* as parameter is
        // incompatible with function decl template<Data> forward(const Data&, Data&))
        // That would need the first argument to be double* const&
        communicator_.forward<CopyGatherScatter>(const_cast<double*>(current), aboveData);
    }
    else
#endif
    {
        if (above.size() > 1)
        {
            // No comunication needed, just copy.
            std::copy(current, current + (above.size() - 1), above.begin()+1);
        }
    }
    return above;
}
std::vector<double> CommunicateAboveBelow::communicateBelow(double last_below,
                                                            const double* current,
                                                            std::size_t size)
{
    std::vector<double> below(size, last_below);

#if HAVE_MPI
    if (comm_.size() > 1)
    {
        auto belowData = below.data();
        // Ugly const_cast needed as my compiler says, that
        // passing const double*& and double* as parameter is
        // incompatible with function decl template<Data> backward(Data&, const Data&)
        // That would need the first argument to be double* const&
        communicator_.backward<CopyGatherScatter>(belowData, const_cast<double*>(current));
    }
    else
#endif
    {
        if (below.size() > 1)
        {
            // No comunication needed, just copy.
            std::copy(current+1, current + below.size(), below.begin());
        }
    }
    return below;
}

void CommunicateAboveBelow::pushBackEclIndex([[maybe_unused]] int above,
                                             [[maybe_unused]] int current,
                                             [[maybe_unused]] bool isOwner)
{
#if HAVE_MPI
    if (comm_.size() > 1)
    {
        Attribute attr = owner;
        if (!isOwner)
        {
            attr = overlap;
        }
        above_indices_.add(above, {count_, attr, true});
        current_indices_.add(current, {count_++, attr, true});
    }
#endif
}


void ParallelWellInfo::DestroyComm::operator()(Communication* comm)
{
#if HAVE_MPI
    // Only delete custom communicators.
    bool del = comm
        && (*comm != Dune::MPIHelper::getLocalCommunicator())
        && (*comm != MPI_COMM_WORLD && *comm != MPI_COMM_NULL);

    if ( del )
    {
        // Not 100% nice but safe as comm is deleted anyway
        // We can only access a copy and no reference.
        MPI_Comm mpi_comm = *comm;
        MPI_Comm_free(&mpi_comm);
    }
#endif
    delete comm;
}

ParallelWellInfo::ParallelWellInfo(const std::string& name,
                                   bool hasLocalCells)
    : name_(name), hasLocalCells_ (hasLocalCells),
      isOwner_(true), rankWithFirstPerf_(-1),
      comm_(new Communication(Dune::MPIHelper::getLocalCommunicator())),
      commAboveBelow_(new CommunicateAboveBelow(*comm_))
{}

ParallelWellInfo::ParallelWellInfo(const std::pair<std::string,bool>& well_info,
                                   [[maybe_unused]] Communication allComm)
    : name_(well_info.first), hasLocalCells_(well_info.second),
      rankWithFirstPerf_(-1)
{
#if HAVE_MPI
    MPI_Comm newComm;
    int color = hasLocalCells_ ? 1 : MPI_UNDEFINED;
    MPI_Comm_split(allComm, color, allComm.rank(), &newComm);
    comm_.reset(new Communication(newComm));
#else
    comm_.reset(new Communication(Dune::MPIHelper::getLocalCommunicator()));
#endif
    commAboveBelow_.reset(new CommunicateAboveBelow(*comm_));
    isOwner_ = (comm_->rank() == 0);
}

void ParallelWellInfo::communicateFirstPerforation(bool hasFirst)
{
    int first = hasFirst;
    std::vector<int> firstVec(comm_->size());
    comm_->allgather(&first, 1, firstVec.data());
    auto found = std::find_if(firstVec.begin(), firstVec.end(),
                              [](int i) -> bool{ return i;});
    rankWithFirstPerf_ = found - firstVec.begin();
}

void ParallelWellInfo::pushBackEclIndex(int above, int current)
{
    commAboveBelow_->pushBackEclIndex(above, current);
}

void ParallelWellInfo::beginReset()
{
    commAboveBelow_->beginReset();
}


void ParallelWellInfo::endReset()
{
    commAboveBelow_->beginReset();
}

void ParallelWellInfo::clearCommunicateAboveBelow()
{
    commAboveBelow_->clear();
}

std::vector<double> ParallelWellInfo::communicateAboveValues(double zero_value,
                                                             const double* current_values,
                                                             std::size_t size) const
{
    return commAboveBelow_->communicateAbove(zero_value, current_values,
                                             size);
}

std::vector<double> ParallelWellInfo::communicateAboveValues(double zero_value,
                                                             const std::vector<double>& current_values) const
{
    return commAboveBelow_->communicateAbove(zero_value, current_values.data(),
                                             current_values.size());
}

std::vector<double> ParallelWellInfo::communicateBelowValues(double last_value,
                                                             const double* current_values,
                                                             std::size_t size) const
{
    return commAboveBelow_->communicateBelow(last_value, current_values,
                                             size);
}

std::vector<double> ParallelWellInfo::communicateBelowValues(double last_value,
                                                             const std::vector<double>& current_values) const
{
    return commAboveBelow_->communicateBelow(last_value, current_values.data(),
                                             current_values.size());
}

bool operator<(const ParallelWellInfo& well1, const ParallelWellInfo& well2)
{
    return well1.name() < well2.name() || (! (well2.name() < well1.name()) && well1.hasLocalCells() < well2.hasLocalCells());
}

bool operator==(const ParallelWellInfo& well1, const ParallelWellInfo& well2)
{
    bool ret = well1.name() == well2.name() && well1.hasLocalCells() == well2.hasLocalCells()
        && well1.isOwner() == well2.isOwner();
#if HAVE_MPI
    using MPIComm = typename Dune::MPIHelper::MPICommunicator;
    ret = ret &&
        static_cast<MPIComm>(well1.communication()) == static_cast<MPIComm>(well2.communication());
#endif
    return ret;
}

bool operator!=(const ParallelWellInfo& well1, const ParallelWellInfo& well2)
{
    return ! (well1 == well2);
}

bool operator<(const std::pair<std::string, bool>& pair, const ParallelWellInfo& well)
{
    return pair.first < well.name() || ( !( well.name() < pair.first ) && pair.second < well.hasLocalCells() );
}

bool operator<( const ParallelWellInfo& well, const std::pair<std::string, bool>& pair)
{
    return well.name() < pair.first || ( !( pair.first < well.name() ) && well.hasLocalCells() < pair.second );
}

bool operator==(const std::pair<std::string, bool>& pair, const ParallelWellInfo& well)
{
    return pair.first == well.name() && pair.second == well.hasLocalCells();
}

bool operator==(const ParallelWellInfo& well, const std::pair<std::string, bool>& pair)
{
    return pair == well;
}

bool operator!=(const std::pair<std::string, bool>& pair, const ParallelWellInfo& well)
{
    return pair.first != well.name() || pair.second != well.hasLocalCells();
}

bool operator!=(const ParallelWellInfo& well, const std::pair<std::string, bool>& pair)
{
    return pair != well;
}

CheckDistributedWellConnections::CheckDistributedWellConnections(const Well& well,
                                                                 const ParallelWellInfo& info)
    : well_(well), pwinfo_(info)
{
    foundConnections_.resize(well.getConnections().size(), 0);
}

void
CheckDistributedWellConnections::connectionFound(std::size_t i)
{
    foundConnections_[i] = 1;
}

bool
CheckDistributedWellConnections::checkAllConnectionsFound()
{
    // Ecl does not hold any information of remote connections.
    assert(pwinfo_.communication().max(foundConnections_.size()) == foundConnections_.size());
    pwinfo_.communication().sum(foundConnections_.data(),
                                foundConnections_.size());

    std::string msg = std::string("Cells with these i,j,k indices were not found ")
        + "in grid (well = " + pwinfo_.name() + "):";
    bool missingCells = false;
    auto start = foundConnections_.begin();
    for(auto conFound = start; conFound != foundConnections_.end(); ++conFound)
    {
        if (*conFound == 0)
        {
            const auto& completion = well_.getConnections()[conFound - start];
            msg = msg + " " + std::to_string(completion.getI()) + "," +
                std::to_string(completion.getJ()) + ","
                + std::to_string(completion.getK()) + " ";
            missingCells = true;
        }
    }
    if (missingCells && pwinfo_.isOwner())
    {
        OPM_THROW(std::runtime_error, msg);
    }
    return !missingCells;
}
} // end namespace Opm