/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Copyright (C) 2012-2025 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 "tetOverlapVolume.H"
#include "polyMesh.H"
#include "OFstream.H"
#include "treeBoundBox.H"
#include "cutTriTet.H"

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

namespace Foam
{
    defineTypeNameAndDebug(tetOverlapVolume, 0);
}


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

Foam::tetOverlapVolume::tetOverlapVolume()
{}


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

Foam::scalar Foam::tetOverlapVolume::tetTetOverlapVol
(
    const tetPointRef& tetA,
    const tetPointRef& tetB
) const
{
    typedef cutTriTet::noOp noOp;

    // A maximum of three cuts are made (the tets that result from the final cut
    // are not stored), and each cut can create at most three tets. The
    // temporary storage must therefore extend to 3^3 = 27 tets.
    typedef cutTetList<27> tetListType;
    static tetListType cutTetList1, cutTetList2;

    // face 0
    const plane pl0(tetB.b(), tetB.d(), tetB.c());
    if (!pl0.valid())
    {
        return 0;
    }
    const FixedList<point, 4> t({tetA.a(), tetA.b(), tetA.c(), tetA.d()});
    cutTetList1.clear();
    tetCut(t, pl0, cutTriTet::appendOp<tetListType>(cutTetList1), noOp());
    if (cutTetList1.size() == 0)
    {
        return 0;
    }

    // face 1
    const plane pl1(tetB.a(), tetB.c(), tetB.d());
    if (!pl1.valid())
    {
        return 0;
    }
    cutTetList2.clear();
    for (label i = 0; i < cutTetList1.size(); i++)
    {
        const FixedList<point, 4>& t = cutTetList1[i];
        tetCut(t, pl1, cutTriTet::appendOp<tetListType>(cutTetList2), noOp());
    }
    if (cutTetList2.size() == 0)
    {
        return 0;
    }

    // face 2
    const plane pl2(tetB.a(), tetB.d(), tetB.b());
    if (!pl2.valid())
    {
        return 0;
    }
    cutTetList1.clear();
    for (label i = 0; i < cutTetList2.size(); i++)
    {
        const FixedList<point, 4>& t = cutTetList2[i];
        tetCut(t, pl2, cutTriTet::appendOp<tetListType>(cutTetList1), noOp());
    }
    if (cutTetList1.size() == 0)
    {
        return 0;
    }

    // face 3
    const plane pl3(tetB.a(), tetB.b(), tetB.c());
    if (!pl3.valid())
    {
        return 0;
    }
    scalar v = 0;
    for (label i = 0; i < cutTetList1.size(); i++)
    {
        const FixedList<point, 4>& t = cutTetList1[i];
        v += tetCut(t, pl3, cutTriTet::volumeOp(), noOp());
    }

    return v;
}


Foam::treeBoundBox Foam::tetOverlapVolume::pyrBb
(
    const pointField& points,
    const face& f,
    const point& fc
) const
{
    treeBoundBox bb(fc, fc);
    forAll(f, fp)
    {
        const point& pt = points[f[fp]];
        bb.min() = min(bb.min(), pt);
        bb.max() = max(bb.max(), pt);
    }
    return bb;
}


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

Foam::scalar Foam::tetOverlapVolume::cellVolumeMinDecomp
(
    const primitiveMesh& mesh,
    const label cellI
) const
{
    const cell& cFaces = mesh.cells()[cellI];
    const point& cc = mesh.cellCentres()[cellI];

    scalar vol = 0.0;

    forAll(cFaces, cF)
    {
        label faceI = cFaces[cF];

        const face& f = mesh.faces()[faceI];

        bool own = (mesh.faceOwner()[faceI] == cellI);

        label tetBasePtI = 0;

        const point& tetBasePt = mesh.points()[f[tetBasePtI]];

        for (label tetPtI = 1; tetPtI < f.size() - 1; tetPtI++)
        {
            label facePtI = (tetPtI + tetBasePtI) % f.size();
            label otherFacePtI = f.fcIndex(facePtI);

            label pt0I = -1;
            label pt1I = -1;

            if (own)
            {
                pt0I = f[facePtI];
                pt1I = f[otherFacePtI];
            }
            else
            {
                pt0I = f[otherFacePtI];
                pt1I = f[facePtI];
            }

            const tetPointRef tet
            (
                cc,
                tetBasePt,
                mesh.points()[pt0I],
                mesh.points()[pt1I]
            );

            vol += tet.mag();
        }
    }

    return vol;
}


bool Foam::tetOverlapVolume::cellCellOverlapMinDecomp
(
    const primitiveMesh& meshA,
    const label cellAI,
    const primitiveMesh& meshB,
    const label cellBI,
    const treeBoundBox& cellBbB,
    const scalar threshold
) const
{
    const cell& cFacesA = meshA.cells()[cellAI];
    const point& ccA = meshA.cellCentres()[cellAI];

    const cell& cFacesB = meshB.cells()[cellBI];
    const point& ccB = meshB.cellCentres()[cellBI];

    scalar vol = 0.0;

    forAll(cFacesA, cFA)
    {
        label faceAI = cFacesA[cFA];

        const face& fA = meshA.faces()[faceAI];
        const treeBoundBox pyrA = pyrBb(meshA.points(), fA, ccA);
        if (!pyrA.overlaps(cellBbB))
        {
            continue;
        }

        bool ownA = (meshA.faceOwner()[faceAI] == cellAI);

        label tetBasePtAI = 0;

        const point& tetBasePtA = meshA.points()[fA[tetBasePtAI]];

        for (label tetPtI = 1; tetPtI < fA.size() - 1; tetPtI++)
        {
            label facePtAI = (tetPtI + tetBasePtAI) % fA.size();
            label otherFacePtAI = fA.fcIndex(facePtAI);

            label pt0I = -1;
            label pt1I = -1;

            if (ownA)
            {
                pt0I = fA[facePtAI];
                pt1I = fA[otherFacePtAI];
            }
            else
            {
                pt0I = fA[otherFacePtAI];
                pt1I = fA[facePtAI];
            }

            const tetPointRef tetA
            (
                ccA,
                tetBasePtA,
                meshA.points()[pt0I],
                meshA.points()[pt1I]
            );
            const treeBoundBox tetABb(tetA.bounds());


            // Loop over tets of cellB
            forAll(cFacesB, cFB)
            {
                label faceBI = cFacesB[cFB];

                const face& fB = meshB.faces()[faceBI];
                const treeBoundBox pyrB = pyrBb(meshB.points(), fB, ccB);
                if (!pyrB.overlaps(pyrA))
                {
                    continue;
                }

                bool ownB = (meshB.faceOwner()[faceBI] == cellBI);

                label tetBasePtBI = 0;

                const point& tetBasePtB = meshB.points()[fB[tetBasePtBI]];

                for (label tetPtI = 1; tetPtI < fB.size() - 1; tetPtI++)
                {
                    label facePtBI = (tetPtI + tetBasePtBI) % fB.size();
                    label otherFacePtBI = fB.fcIndex(facePtBI);

                    label pt0I = -1;
                    label pt1I = -1;

                    if (ownB)
                    {
                        pt0I = fB[facePtBI];
                        pt1I = fB[otherFacePtBI];
                    }
                    else
                    {
                        pt0I = fB[otherFacePtBI];
                        pt1I = fB[facePtBI];
                    }

                    const tetPointRef tetB
                    (
                        ccB,
                        tetBasePtB,
                        meshB.points()[pt0I],
                        meshB.points()[pt1I]
                    );

                    if (!tetB.bounds().overlaps(tetABb))
                    {
                        continue;
                    }

                    vol += tetTetOverlapVol(tetA, tetB);

                    if (vol > threshold)
                    {
                        return true;
                    }
                }
            }
        }
    }

    return false;
}


Foam::scalar Foam::tetOverlapVolume::cellCellOverlapVolumeMinDecomp
(
    const primitiveMesh& meshA,
    const label cellAI,
    const primitiveMesh& meshB,
    const label cellBI,
    const treeBoundBox& cellBbB
) const
{
    const cell& cFacesA = meshA.cells()[cellAI];
    const point& ccA = meshA.cellCentres()[cellAI];

    const cell& cFacesB = meshB.cells()[cellBI];
    const point& ccB = meshB.cellCentres()[cellBI];

    scalar vol = 0.0;

    forAll(cFacesA, cFA)
    {
        label faceAI = cFacesA[cFA];

        const face& fA = meshA.faces()[faceAI];
        const treeBoundBox pyrA = pyrBb(meshA.points(), fA, ccA);
        if (!pyrA.overlaps(cellBbB))
        {
            continue;
        }

        bool ownA = (meshA.faceOwner()[faceAI] == cellAI);

        label tetBasePtAI = 0;

        const point& tetBasePtA = meshA.points()[fA[tetBasePtAI]];

        for (label tetPtI = 1; tetPtI < fA.size() - 1; tetPtI++)
        {
            label facePtAI = (tetPtI + tetBasePtAI) % fA.size();
            label otherFacePtAI = fA.fcIndex(facePtAI);

            label pt0I = -1;
            label pt1I = -1;

            if (ownA)
            {
                pt0I = fA[facePtAI];
                pt1I = fA[otherFacePtAI];
            }
            else
            {
                pt0I = fA[otherFacePtAI];
                pt1I = fA[facePtAI];
            }

            const tetPointRef tetA
            (
                ccA,
                tetBasePtA,
                meshA.points()[pt0I],
                meshA.points()[pt1I]
            );
            const treeBoundBox tetABb(tetA.bounds());


            // Loop over tets of cellB
            forAll(cFacesB, cFB)
            {
                label faceBI = cFacesB[cFB];

                const face& fB = meshB.faces()[faceBI];
                const treeBoundBox pyrB = pyrBb(meshB.points(), fB, ccB);
                if (!pyrB.overlaps(pyrA))
                {
                    continue;
                }

                bool ownB = (meshB.faceOwner()[faceBI] == cellBI);

                label tetBasePtBI = 0;

                const point& tetBasePtB = meshB.points()[fB[tetBasePtBI]];

                for (label tetPtI = 1; tetPtI < fB.size() - 1; tetPtI++)
                {
                    label facePtBI = (tetPtI + tetBasePtBI) % fB.size();
                    label otherFacePtBI = fB.fcIndex(facePtBI);

                    label pt0I = -1;
                    label pt1I = -1;

                    if (ownB)
                    {
                        pt0I = fB[facePtBI];
                        pt1I = fB[otherFacePtBI];
                    }
                    else
                    {
                        pt0I = fB[otherFacePtBI];
                        pt1I = fB[facePtBI];
                    }

                    const tetPointRef tetB
                    (
                        ccB,
                        tetBasePtB,
                        meshB.points()[pt0I],
                        meshB.points()[pt1I]
                    );
                    if (!tetB.bounds().overlaps(tetABb))
                    {
                        continue;
                    }

                    vol += tetTetOverlapVol(tetA, tetB);
                }
            }
        }
    }

    return vol;
}


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