/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Copyright (C) 2015-2022 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

    OpenFOAM 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.

    OpenFOAM 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 OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.

Class
    Foam::distributionMapBase

Description
    Class containing processor-to-processor mapping information.

    We store mapping from the bits-to-send to the complete starting list
    (subXXXMap) and from the received bits to their location in the new
    list (constructXXXMap).

    Schedule is a list of processor pairs (one send, one receive. One of
    them will be myself) which forms a scheduled (i.e. non-buffered) exchange.
    See distribute on how to use it.
    Note2: number of items sent on one processor have to equal the number
    of items received on the other processor.

    To aid constructing these maps there are the constructors from global
    numbering, either with or without transforms.

    Constructors using compact numbering: layout is
    - all my own elements first (whether used or not)
    - followed by used-only remote elements sorted by remote processor.
    So e.g 4 procs and on proc 1 the compact
    table will first have all globalIndex.localSize() elements from proc1
    followed by used-only elements of proc0, proc2, proc3.
    The constructed distributionMapBase sends the local elements from and
    receives the remote elements into their compact position.
    compactMap[proci] is the position of elements from proci in the compact
    map. compactMap[myProcNo()] is empty since trivial addressing.

    It rewrites the input global indices into indices into the constructed
    data.

    When constructing from components optionally a 'flip' on
    the maps can be specified. This will interpret the map
    values as index+flip, similar to e.g. faceProcAddressing. The flip
    will only be applied to fieldTypes (scalar, vector, .. triad)

SourceFiles
    distributionMapBase.C
    distributionMapBaseTemplates.C

\*---------------------------------------------------------------------------*/

#ifndef distributionMapBase_H
#define distributionMapBase_H

#include "labelList.H"
#include "labelPair.H"
#include "Pstream.H"
#include "boolList.H"
#include "Map.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

class globalIndex;
class PstreamBuffers;

// Forward declaration of friend functions and operators

class distributionMapBase;

Istream& operator>>(Istream&, distributionMapBase&);
Ostream& operator<<(Ostream&, const distributionMapBase&);


/*---------------------------------------------------------------------------*\
                      Class distributionMapBase Declaration
\*---------------------------------------------------------------------------*/

class distributionMapBase
{
protected:

    // Protected data

        //- Size of reconstructed data
        label constructSize_;

        //- Maps from subsetted data back to original data
        labelListList subMap_;

        //- Maps from subsetted data to new reconstructed data
        labelListList constructMap_;

        //- Whether subMap includes flip or not
        bool subHasFlip_;

        //- Whether constructMap includes flip or not
        bool constructHasFlip_;


        //- Schedule
        mutable autoPtr<List<labelPair>> schedulePtr_;


    // Private Member Functions

        static void checkReceivedSize
        (
            const label proci,
            const label expectedSize,
            const label receivedSize
        );

        //- Construct per processor compact addressing of the global elements
        //  needed. The ones from the local processor are not included since
        //  these are always all needed.
        void calcCompactAddressing
        (
            const globalIndex& globalNumbering,
            const labelList& elements,
            List<Map<label>>& compactMap
        ) const;

        void calcCompactAddressing
        (
            const globalIndex& globalNumbering,
            const labelListList& elements,
            List<Map<label>>& compactMap
        ) const;

        void exchangeAddressing
        (
            const int tag,
            const globalIndex& globalNumbering,
            labelList& elements,
            List<Map<label>>& compactMap,
            labelList& compactStart
        );
        void exchangeAddressing
        (
            const int tag,
            const globalIndex& globalNumbering,
            labelListList& elements,
            List<Map<label>>& compactMap,
            labelList& compactStart
        );

        template<class T, class CombineOp, class negateOp>
        static void flipAndCombine
        (
            const UList<label>& map,
            const bool hasFlip,
            const UList<T>& rhs,
            const CombineOp& cop,
            const negateOp& negOp,
            List<T>& lhs
        );

        template<class T, class negateOp>
        static T accessAndFlip
        (
            const UList<T>& fld,
            const label index,
            const bool hasFlip,
            const negateOp& negOp
        );

public:

    // Declare name of the class and its debug switch
    ClassName("distributionMapBase");


    // Constructors

        //- Construct null
        distributionMapBase();

        //- Move construct from components
        distributionMapBase
        (
            const label constructSize,
            const labelListList&& subMap,
            const labelListList&& constructMap,
            const bool subHasFlip = false,
            const bool constructHasFlip = false
        );

        //- Construct from reverse addressing: per data item the send
        //  processor and the receive processor. (note: data is not stored
        //  sorted per processor so cannot use printLayout).
        distributionMapBase
        (
            const labelList& sendProcs,
            const labelList& recvProcs
        );

        //- Construct from list of (possibly) remote elements in globalIndex
        //  numbering (or -1). Determines compact numbering (see above) and
        //  distribute map to get data into this ordering and renumbers the
        //  elements to be in compact numbering.
        distributionMapBase
        (
            const globalIndex&,
            labelList& elements,
            List<Map<label>>& compactMap,
            const int tag = Pstream::msgType()
        );

        //- Special variant that works with the info sorted into bins
        //  according to local indices. E.g. think cellCells where
        //  cellCells[localCellI] is a list of global cells
        distributionMapBase
        (
            const globalIndex&,
            labelListList& cellCells,
            List<Map<label>>& compactMap,
            const int tag = Pstream::msgType()
        );

        //- Construct copy
        distributionMapBase(const distributionMapBase&);

        //- Move constructor
        distributionMapBase(distributionMapBase&&);

        //- Construct from Istream
        distributionMapBase(Istream&);


    // Member Functions

        // Access

            //- Constructed data size
            label constructSize() const
            {
                return constructSize_;
            }

            //- Constructed data size
            label& constructSize()
            {
                return constructSize_;
            }

            //- From subsetted data back to original data
            const labelListList& subMap() const
            {
                return subMap_;
            }

            //- From subsetted data back to original data
            labelListList& subMap()
            {
                return subMap_;
            }

            //- From subsetted data to new reconstructed data
            const labelListList& constructMap() const
            {
                return constructMap_;
            }

            //- From subsetted data to new reconstructed data
            labelListList& constructMap()
            {
                return constructMap_;
            }

            //- Does subMap include a sign
            bool subHasFlip() const
            {
                return subHasFlip_;
            }

            //- Does subMap include a sign
            bool& subHasFlip()
            {
                return subHasFlip_;
            }

            //- Does constructMap include a sign
            bool constructHasFlip() const
            {
                return constructHasFlip_;
            }

            //- Does constructMap include a sign
            bool& constructHasFlip()
            {
                return constructHasFlip_;
            }

            //- Calculate a schedule. See above.
            static List<labelPair> schedule
            (
                const labelListList& subMap,
                const labelListList& constructMap,
                const int tag
            );

            //- Return a schedule. Demand driven. See above.
            const List<labelPair>& schedule() const;


        // Other

            //- Transfer the contents of the argument and annul the argument.
            void transfer(distributionMapBase&);

            //- Helper for construct from globalIndex. Renumbers element
            //  (in globalIndex numbering) into compact indices.
            static label renumber
            (
                const globalIndex&,
                const List<Map<label>>& compactMap,
                const label globalElement
            );

            //- Compact maps. Gets per field a bool whether it is used (locally)
            //  and works out itself what this side and sender side can remove
            //  from maps. Only compacts non-local elements (i.e. the stuff
            //  that gets sent over), does not change the local layout
            void compact
            (
                const boolList& elemIsUsed,
                const int tag = UPstream::msgType()
            );

            //- Compact all maps and layout. Returns compaction maps for
            //  subMap and constructMap
            void compact
            (
                const boolList& elemIsUsed,
                const label localSize,            // max index for subMap
                labelList& oldToNewSub,
                labelList& oldToNewConstruct,
                const int tag = UPstream::msgType()
            );

            //- Distribute data. Note:schedule only used for
            //  Pstream::commsTypes::scheduled for now, all others just use
            //  send-to-all, receive-from-all.
            template<class T, class negateOp>
            static void distribute
            (
                const Pstream::commsTypes commsType,
                const List<labelPair>& schedule,
                const label constructSize,
                const labelListList& subMap,
                const bool subHasFlip,
                const labelListList& constructMap,
                const bool constructHasFlip,
                List<T>&,
                const negateOp& negOp,
                const int tag = UPstream::msgType()
            );

            //- Distribute data. If multiple processors writing to same
            //  position adds contributions using cop.
            template<class T, class CombineOp, class negateOp>
            static void distribute
            (
                const Pstream::commsTypes commsType,
                const List<labelPair>& schedule,
                const label constructSize,
                const labelListList& subMap,
                const bool subHasFlip,
                const labelListList& constructMap,
                const bool constructHasFlip,
                List<T>&,
                const CombineOp& cop,
                const negateOp& negOp,
                const T& nullValue,
                const int tag = UPstream::msgType()
            );

            //- Distribute data using default commsType.
            template<class T>
            void distribute
            (
                List<T>& fld,
                const int tag = UPstream::msgType()
            ) const;

            //- Distribute data using default commsType.
            template<class T, class negateOp>
            void distribute
            (
                List<T>& fld,
                const negateOp& negOp,
                const int tag = UPstream::msgType()
            ) const;

            //- Distribute data using default commsType.
            template<class T>
            void distribute
            (
                DynamicList<T>& fld,
                const int tag = UPstream::msgType()
            ) const;

            //- Reverse distribute data using default commsType.
            template<class T>
            void reverseDistribute
            (
                const label constructSize,
                List<T>&,
                const int tag = UPstream::msgType()
            ) const;

            //- Reverse distribute data using default commsType.
            //  Since constructSize might be larger than supplied size supply
            //  a nullValue
            template<class T>
            void reverseDistribute
            (
                const label constructSize,
                const T& nullValue,
                List<T>& fld,
                const int tag = UPstream::msgType()
            ) const;

            //- Do all sends using PstreamBuffers
            template<class T>
            void send(PstreamBuffers&, const List<T>&) const;
            //- Do all receives using PstreamBuffers
            template<class T>
            void receive(PstreamBuffers&, List<T>&) const;

            //- Debug: print layout. Can only be used on maps with sorted
            //  storage (local data first, then non-local data)
            void printLayout(Ostream& os) const;


    // Member Operators

        void operator=(const distributionMapBase&);
        void operator=(distributionMapBase&&);


    // IOstream Operators

        //- Read dictionary from Istream
        friend Istream& operator>>(Istream&, distributionMapBase&);

        //- Write dictionary to Ostream
        friend Ostream& operator<<(Ostream&, const distributionMapBase&);
};


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#ifdef NoRepository
    #include "distributionMapBaseTemplates.C"
#endif

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //