/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011-2016 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/>.

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

#include "Pstream.H"
#include "functionObjectList.H"
#include "wallBoundedStreamLine.H"
#include "fvMesh.H"
#include "wallBoundedStreamLineParticleCloud.H"
#include "ReadFields.H"
#include "meshSearch.H"
#include "sampledSet.H"
#include "globalIndex.H"
#include "mapDistribute.H"
#include "interpolationCellPoint.H"
#include "PatchTools.H"
#include "meshSearchMeshObject.H"
#include "faceSet.H"

// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //

namespace Foam
{
defineTypeNameAndDebug(wallBoundedStreamLine, 0);
}


// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //

Foam::autoPtr<Foam::indirectPrimitivePatch>
Foam::wallBoundedStreamLine::wallPatch() const
{
    const fvMesh& mesh = dynamic_cast<const fvMesh&>(obr_);

    const polyBoundaryMesh& patches = mesh.boundaryMesh();

    label nFaces = 0;

    forAll(patches, patchi)
    {
        //if (!polyPatch::constraintType(patches[patchi].type()))
        if (isA<wallPolyPatch>(patches[patchi]))
        {
            nFaces += patches[patchi].size();
        }
    }

    labelList addressing(nFaces);

    nFaces = 0;

    forAll(patches, patchi)
    {
        //if (!polyPatch::constraintType(patches[patchi].type()))
        if (isA<wallPolyPatch>(patches[patchi]))
        {
            const polyPatch& pp = patches[patchi];

            forAll(pp, i)
            {
                addressing[nFaces++] = pp.start()+i;
            }
        }
    }

    return autoPtr<indirectPrimitivePatch>
    (
        new indirectPrimitivePatch
        (
            IndirectList<face>
            (
                mesh.faces(),
                addressing
            ),
            mesh.points()
        )
    );
}


Foam::tetIndices Foam::wallBoundedStreamLine::findNearestTet
(
    const PackedBoolList& isWallPatch,
    const point& seedPt,
    const label celli
) const
{
    const fvMesh& mesh = dynamic_cast<const fvMesh&>(obr_);

    const cell& cFaces = mesh.cells()[celli];

    label minFacei = -1;
    label minTetPtI = -1;
    scalar minDistSqr = sqr(GREAT);

    forAll(cFaces, cFacei)
    {
        label facei = cFaces[cFacei];

        if (isWallPatch[facei])
        {
            const face& f = mesh.faces()[facei];
            const label fp0 = mesh.tetBasePtIs()[facei];
            const point& basePoint = mesh.points()[f[fp0]];

            label fp = f.fcIndex(fp0);
            for (label i = 2; i < f.size(); i++)
            {
                const point& thisPoint = mesh.points()[f[fp]];
                label nextFp = f.fcIndex(fp);
                const point& nextPoint = mesh.points()[f[nextFp]];

                const triPointRef tri(basePoint, thisPoint, nextPoint);

                scalar d2 = magSqr(tri.centre() - seedPt);
                if (d2 < minDistSqr)
                {
                    minDistSqr = d2;
                    minFacei = facei;
                    minTetPtI = i-1;
                }
                fp = nextFp;
            }
        }
    }

    // Put particle in tet
    return tetIndices
    (
        celli,
        minFacei,
        minTetPtI,
        mesh
    );
}


void Foam::wallBoundedStreamLine::track()
{
    const Time& runTime = obr_.time();
    const fvMesh& mesh = dynamic_cast<const fvMesh&>(obr_);


    // Determine the 'wall' patches
    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    // These are the faces that need to be followed

    autoPtr<indirectPrimitivePatch> boundaryPatch(wallPatch());
    PackedBoolList isWallPatch(mesh.nFaces());
    forAll(boundaryPatch().addressing(), i)
    {
        isWallPatch[boundaryPatch().addressing()[i]] = 1;
    }



    // Find nearest wall particle for the seedPoints
    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    IDLList<wallBoundedStreamLineParticle> initialParticles;
    wallBoundedStreamLineParticleCloud particles
    (
        mesh,
        cloudName_,
        initialParticles
    );

    {
        // Get the seed points
        // ~~~~~~~~~~~~~~~~~~~

        const sampledSet& seedPoints = sampledSetPtr_();


        forAll(seedPoints, i)
        {
            const point& seedPt = seedPoints[i];
            label celli = seedPoints.cells()[i];

            tetIndices ids(findNearestTet(isWallPatch, seedPt, celli));

            if (ids.face() != -1 && isWallPatch[ids.face()])
            {
                //Pout<< "Seeding particle :" << nl
                //    << "     seedPt:" << seedPt << nl
                //    << "     face  :" << ids.face() << nl
                //    << "     at    :" << mesh.faceCentres()[ids.face()] << nl
                //    << "     cell  :" << mesh.cellCentres()[ids.cell()] << nl
                //    << endl;

                particles.addParticle
                (
                    new wallBoundedStreamLineParticle
                    (
                        mesh,
                        ids.faceTri(mesh).centre(),
                        ids.cell(),
                        ids.face(),     // tetFace
                        ids.tetPt(),
                        -1,             // not on a mesh edge
                        -1,             // not on a diagonal edge
                        lifeTime_       // lifetime
                    )
                );
            }
            else
            {
                Pout<< type() << " : ignoring seed " << seedPt
                    << " since not in wall cell." << endl;
            }
        }
    }

    label nSeeds = returnReduce(particles.size(), sumOp<label>());

    Info<< type() << " : seeded " << nSeeds << " particles." << endl;



    // Read or lookup fields
    PtrList<volScalarField> vsFlds;
    PtrList<interpolation<scalar>> vsInterp;
    PtrList<volVectorField> vvFlds;
    PtrList<interpolation<vector>> vvInterp;

    label UIndex = -1;

    if (loadFromFiles_)
    {
        IOobjectList allObjects(mesh, runTime.timeName());

        IOobjectList objects(2*fields_.size());
        forAll(fields_, i)
        {
            objects.add(*allObjects[fields_[i]]);
        }

        ReadFields(mesh, objects, vsFlds);
        vsInterp.setSize(vsFlds.size());
        forAll(vsFlds, i)
        {
            vsInterp.set
            (
                i,
                interpolation<scalar>::New
                (
                    interpolationScheme_,
                    vsFlds[i]
                )
            );
        }
        ReadFields(mesh, objects, vvFlds);
        vvInterp.setSize(vvFlds.size());
        forAll(vvFlds, i)
        {
            vvInterp.set
            (
                i,
                interpolation<vector>::New
                (
                    interpolationScheme_,
                    vvFlds[i]
                )
            );
        }
    }
    else
    {
        label nScalar = 0;
        label nVector = 0;

        forAll(fields_, i)
        {
            if (mesh.foundObject<volScalarField>(fields_[i]))
            {
                nScalar++;
            }
            else if (mesh.foundObject<volVectorField>(fields_[i]))
            {
                nVector++;
            }
            else
            {
                FatalErrorInFunction
                    << "Cannot find field " << fields_[i] << endl
                    << "Valid scalar fields are:"
                    << mesh.names(volScalarField::typeName) << endl
                    << "Valid vector fields are:"
                    << mesh.names(volVectorField::typeName)
                    << exit(FatalError);
            }
        }
        vsInterp.setSize(nScalar);
        nScalar = 0;
        vvInterp.setSize(nVector);
        nVector = 0;

        forAll(fields_, i)
        {
            if (mesh.foundObject<volScalarField>(fields_[i]))
            {
                const volScalarField& f = mesh.lookupObject<volScalarField>
                (
                    fields_[i]
                );
                vsInterp.set
                (
                    nScalar++,
                    interpolation<scalar>::New
                    (
                        interpolationScheme_,
                        f
                    )
                );
            }
            else if (mesh.foundObject<volVectorField>(fields_[i]))
            {
                const volVectorField& f = mesh.lookupObject<volVectorField>
                (
                    fields_[i]
                );

                if (f.name() == UName_)
                {
                    UIndex = nVector;
                }

                vvInterp.set
                (
                    nVector++,
                    interpolation<vector>::New
                    (
                        interpolationScheme_,
                        f
                    )
                );
            }
        }
    }

    // Store the names
    scalarNames_.setSize(vsInterp.size());
    forAll(vsInterp, i)
    {
        scalarNames_[i] = vsInterp[i].psi().name();
    }
    vectorNames_.setSize(vvInterp.size());
    forAll(vvInterp, i)
    {
        vectorNames_[i] = vvInterp[i].psi().name();
    }

    // Check that we know the index of U in the interpolators.

    if (UIndex == -1)
    {
        FatalErrorInFunction
            << "Cannot find field to move particles with : " << UName_
            << endl
            << "This field has to be present in the sampled fields "
            << fields_
            << " and in the objectRegistry." << endl
            << exit(FatalError);
    }

    // Sampled data
    // ~~~~~~~~~~~~

    // Size to maximum expected sizes.
    allTracks_.clear();
    allTracks_.setCapacity(nSeeds);
    allScalars_.setSize(vsInterp.size());
    forAll(allScalars_, i)
    {
        allScalars_[i].clear();
        allScalars_[i].setCapacity(nSeeds);
    }
    allVectors_.setSize(vvInterp.size());
    forAll(allVectors_, i)
    {
        allVectors_[i].clear();
        allVectors_[i].setCapacity(nSeeds);
    }


    // additional particle info
    wallBoundedStreamLineParticle::trackingData td
    (
        particles,
        vsInterp,
        vvInterp,
        UIndex,         // index of U in vvInterp
        trackForward_,  // track in +u direction?
        trackLength_,   // fixed track length
        isWallPatch,    // which faces are to follow

        allTracks_,
        allScalars_,
        allVectors_
    );


    // Set very large dt. Note: cannot use GREAT since 1/GREAT is SMALL
    // which is a trigger value for the tracking...
    const scalar trackTime = Foam::sqrt(GREAT);

    // Track
    particles.move(td, trackTime);
}


// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //

Foam::wallBoundedStreamLine::wallBoundedStreamLine
(
    const word& name,
    const objectRegistry& obr,
    const dictionary& dict,
    const bool loadFromFiles
)
:
    dict_(dict),
    name_(name),
    obr_(obr),
    loadFromFiles_(loadFromFiles),
    active_(true)
{
    // Only active if a fvMesh is available
    if (isA<fvMesh>(obr_))
    {
        read(dict_);
    }
    else
    {
        active_ = false;
        WarningInFunction
            << "No fvMesh available, deactivating " << name_
            << nl << endl;
    }
}


// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //

Foam::wallBoundedStreamLine::~wallBoundedStreamLine()
{}


// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //

void Foam::wallBoundedStreamLine::read(const dictionary& dict)
{
    if (active_)
    {
        //dict_ = dict;
        dict.lookup("fields") >> fields_;
        if (dict.found("UName"))
        {
            dict.lookup("UName") >> UName_;
        }
        else
        {
            UName_ = "U";
            if (dict.found("U"))
            {
                IOWarningInFunction
                (
                    dict
                )   << "Using deprecated entry \"U\"."
                    << " Please use \"UName\" instead."
                    << endl;
                dict.lookup("U") >> UName_;
            }
        }

        if (findIndex(fields_, UName_) == -1)
        {
            FatalIOErrorInFunction
            (
                dict
            )   << "Velocity field for tracking " << UName_
                << " should be present in the list of fields " << fields_
                << exit(FatalIOError);
        }


        dict.lookup("trackForward") >> trackForward_;
        dict.lookup("lifeTime") >> lifeTime_;
        if (lifeTime_ < 1)
        {
            FatalErrorInFunction
                << "Illegal value " << lifeTime_ << " for lifeTime"
                << exit(FatalError);
        }
        trackLength_ = VGREAT;
        if (dict.found("trackLength"))
        {
            dict.lookup("trackLength") >> trackLength_;

            Info<< type() << " : fixed track length specified : "
                << trackLength_ << nl << endl;
        }


        interpolationScheme_ = dict.lookupOrDefault
        (
            "interpolationScheme",
            interpolationCellPoint<scalar>::typeName
        );

        //Info<< typeName << " using interpolation " << interpolationScheme_
        //    << endl;

        cloudName_ = dict.lookupOrDefault<word>
        (
            "cloudName",
            "wallBoundedStreamLine"
        );
        dict.lookup("seedSampleSet") >> seedSet_;

        const fvMesh& mesh = dynamic_cast<const fvMesh&>(obr_);

        const dictionary& coeffsDict = dict.subDict(seedSet_ + "Coeffs");

        sampledSetPtr_ = sampledSet::New
        (
            seedSet_,
            mesh,
            meshSearchMeshObject::New(mesh),
            coeffsDict
        );
        coeffsDict.lookup("axis") >> sampledSetAxis_;

        scalarFormatterPtr_ = writer<scalar>::New(dict.lookup("setFormat"));
        vectorFormatterPtr_ = writer<vector>::New(dict.lookup("setFormat"));


        // Make sure that the mesh is trackable
        if (debug)
        {
            // 1. positive volume decomposition tets
            faceSet faces(mesh, "lowQualityTetFaces", mesh.nFaces()/100+1);
            if
            (
                polyMeshTetDecomposition::checkFaceTets
                (
                    mesh,
                    polyMeshTetDecomposition::minTetQuality,
                    true,
                    &faces
                )
            )
            {
                label nFaces = returnReduce(faces.size(), sumOp<label>());

                WarningInFunction
                    << "Found " << nFaces
                    <<" faces with low quality or negative volume "
                    << "decomposition tets. Writing to faceSet " << faces.name()
                    << endl;
            }

            // 2. all edges on a cell having two faces
            EdgeMap<label> numFacesPerEdge;
            forAll(mesh.cells(), celli)
            {
                const cell& cFaces = mesh.cells()[celli];

                numFacesPerEdge.clear();

                forAll(cFaces, cFacei)
                {
                    label facei = cFaces[cFacei];
                    const face& f = mesh.faces()[facei];
                    forAll(f, fp)
                    {
                        const edge e(f[fp], f.nextLabel(fp));
                        EdgeMap<label>::iterator eFnd =
                            numFacesPerEdge.find(e);
                        if (eFnd != numFacesPerEdge.end())
                        {
                            eFnd()++;
                        }
                        else
                        {
                            numFacesPerEdge.insert(e, 1);
                        }
                    }
                }

                forAllConstIter(EdgeMap<label>, numFacesPerEdge, iter)
                {
                    if (iter() != 2)
                    {
                        FatalErrorInFunction
                            << "problem cell:" << celli
                            << abort(FatalError);
                    }
                }
            }
        }
    }
}


void Foam::wallBoundedStreamLine::execute()
{}


void Foam::wallBoundedStreamLine::end()
{}


void Foam::wallBoundedStreamLine::timeSet()
{}


void Foam::wallBoundedStreamLine::write()
{
    if (active_)
    {
        const Time& runTime = obr_.time();
        const fvMesh& mesh = dynamic_cast<const fvMesh&>(obr_);


        // Do all injection and tracking
        track();


        if (Pstream::parRun())
        {
            // Append slave tracks to master ones
            // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

            globalIndex globalTrackIDs(allTracks_.size());

            // Construct a distribution map to pull all to the master.
            labelListList sendMap(Pstream::nProcs());
            labelListList recvMap(Pstream::nProcs());

            if (Pstream::master())
            {
                // Master: receive all. My own first, then consecutive
                // processors.
                label trackI = 0;

                forAll(recvMap, proci)
                {
                    labelList& fromProc = recvMap[proci];
                    fromProc.setSize(globalTrackIDs.localSize(proci));
                    forAll(fromProc, i)
                    {
                        fromProc[i] = trackI++;
                    }
                }
            }

            labelList& toMaster = sendMap[0];
            toMaster.setSize(globalTrackIDs.localSize());
            forAll(toMaster, i)
            {
                toMaster[i] = i;
            }

            const mapDistribute distMap
            (
                globalTrackIDs.size(),
                sendMap.xfer(),
                recvMap.xfer()
            );


            // Distribute the track positions. Note: use scheduled comms
            // to prevent buffering.
            mapDistribute::distribute
            (
                Pstream::scheduled,
                distMap.schedule(),
                distMap.constructSize(),
                distMap.subMap(),
                distMap.constructMap(),
                allTracks_
            );

            // Distribute the scalars
            forAll(allScalars_, scalarI)
            {
                mapDistribute::distribute
                (
                    Pstream::scheduled,
                    distMap.schedule(),
                    distMap.constructSize(),
                    distMap.subMap(),
                    distMap.constructMap(),
                    allScalars_[scalarI]
                );
            }
            // Distribute the vectors
            forAll(allVectors_, vectorI)
            {
                mapDistribute::distribute
                (
                    Pstream::scheduled,
                    distMap.schedule(),
                    distMap.constructSize(),
                    distMap.subMap(),
                    distMap.constructMap(),
                    allVectors_[vectorI]
                );
            }
        }


        label n = 0;
        forAll(allTracks_, trackI)
        {
            n += allTracks_[trackI].size();
        }

        Info<< "    Tracks:" << allTracks_.size() << nl
            << "    Total samples:" << n << endl;


        // Massage into form suitable for writers
        // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

        if (Pstream::master() && allTracks_.size())
        {
            // Make output directory

            fileName vtkPath
            (
                Pstream::parRun()
              ? runTime.path()/".."/"postProcessing"/"sets"/name()
              : runTime.path()/"postProcessing"/"sets"/name()
            );
            if (mesh.name() != fvMesh::defaultRegion)
            {
                vtkPath = vtkPath/mesh.name();
            }
            vtkPath = vtkPath/mesh.time().timeName();

            mkDir(vtkPath);

            // Convert track positions

            PtrList<coordSet> tracks(allTracks_.size());
            forAll(allTracks_, trackI)
            {
                tracks.set
                (
                    trackI,
                    new coordSet
                    (
                        "track" + Foam::name(trackI),
                        sampledSetAxis_                 //"xyz"
                    )
                );
                tracks[trackI].transfer(allTracks_[trackI]);
            }

            // Convert scalar values

            if (allScalars_.size() > 0)
            {
                List<List<scalarField>> scalarValues(allScalars_.size());

                forAll(allScalars_, scalarI)
                {
                    DynamicList<scalarList>& allTrackVals =
                        allScalars_[scalarI];
                    scalarValues[scalarI].setSize(allTrackVals.size());

                    forAll(allTrackVals, trackI)
                    {
                        scalarList& trackVals = allTrackVals[trackI];
                        scalarValues[scalarI][trackI].transfer(trackVals);
                    }
                }

                fileName vtkFile
                (
                    vtkPath
                  / scalarFormatterPtr_().getFileName
                    (
                        tracks[0],
                        scalarNames_
                    )
                );

                Info<< "Writing data to " << vtkFile.path() << endl;

                scalarFormatterPtr_().write
                (
                    true,           // writeTracks
                    tracks,
                    scalarNames_,
                    scalarValues,
                    OFstream(vtkFile)()
                );
            }

            // Convert vector values

            if (allVectors_.size() > 0)
            {
                List<List<vectorField>> vectorValues(allVectors_.size());

                forAll(allVectors_, vectorI)
                {
                    DynamicList<vectorList>& allTrackVals =
                        allVectors_[vectorI];
                    vectorValues[vectorI].setSize(allTrackVals.size());

                    forAll(allTrackVals, trackI)
                    {
                        vectorList& trackVals = allTrackVals[trackI];
                        vectorValues[vectorI][trackI].transfer(trackVals);
                    }
                }

                fileName vtkFile
                (
                    vtkPath
                  / vectorFormatterPtr_().getFileName
                    (
                        tracks[0],
                        vectorNames_
                    )
                );

                //Info<< "Writing vector data to " << vtkFile << endl;

                vectorFormatterPtr_().write
                (
                    true,           // writeTracks
                    tracks,
                    vectorNames_,
                    vectorValues,
                    OFstream(vtkFile)()
                );
            }
        }
    }
}


void Foam::wallBoundedStreamLine::updateMesh(const mapPolyMesh&)
{
    read(dict_);
}


void Foam::wallBoundedStreamLine::movePoints(const polyMesh&)
{
    // Moving mesh affects the search tree
    read(dict_);
}


//void Foam::wallBoundedStreamLine::readUpdate
//(const polyMesh::readUpdateState state)
//{
//    if (state != UNCHANGED)
//    {
//        read(dict_);
//    }
//}


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