/*---------------------------------------------------------------------------*\
  ==  == ====== ====   ====    |
                    \\     ||  | Multiphase Code Repository by HZDR
  ======   //   ||  || ===//   | Website: https://doi.org/10.14278/rodare.767
  ||  ||  //    ||  // || \\   | License: GPL-3.0-or-later
  ==  == ====== ====   ==  ==  |
-------------------------------------------------------------------------------
License
    This file is part of the Multiphase Code Repository by HZDR.

    Copyright (C) 2025 by Helmholtz-Zentrum Dresden-Rossendorf e.V. (HZDR),
    Website: https://hzdr.de

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    Multiphase Code Repository by HZDR is free software: you can redistribute
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\*---------------------------------------------------------------------------*/

#include "volFields.H"
#include "addonFvcSpread.H"

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

template<class fieldType>
Foam::tmp<Foam::volScalarField> Foam::fvc::spreadInterface
(
    fieldType& field,
    const volScalarField& alpha,
    const label nLayers,
    const scalar alphaDiff
)
{
    const fvMesh& mesh = field.mesh();

    const labelUList& owner = mesh.owner();
    const labelUList& neighbour = mesh.neighbour();

    tmp<volScalarField> infoLocation
    (
        new volScalarField
        (
            IOobject("infoLocation", mesh.time().name(), mesh),
            mesh,
            dimensionedScalar(dimless, Zero)
        )
    );

    volScalarField alphaInfo(alpha);
    volScalarField generation
    (
        IOobject("generation", mesh.time().name(), mesh),
        mesh,
        dimensionedScalar(dimless, Zero)
    );

    for (int i = 0; i < nLayers; i++)
    {
        const fieldType field0(field);
        const volScalarField alphaInfo0(alphaInfo);
        const volScalarField generation0(generation);

        forAll(owner, facei)
        {
            const label own = owner[facei];
            const label nbr = neighbour[facei];

            if (mag(alpha[own] - alpha[nbr]) > alphaDiff)
            {
                if
                (
                    (alpha[nbr] < alpha[own])
                 && (alphaInfo[nbr] < alphaInfo0[own])
                 && (generation[nbr] >= generation0[own])
                )
                {
                    field[nbr] = field0[own];
                    alphaInfo[nbr] = alphaInfo0[own];
                    infoLocation.ref()[own] = 1;
                    infoLocation.ref()[nbr] = 1;
                    generation[nbr] = generation0[own] + 1;
                }
                else if
                (
                    (alpha[own] < alpha[nbr])
                 && (alphaInfo[own] < alphaInfo0[nbr])
                 && (generation[own] >= generation0[nbr])
                )
                {
                    field[own] = field0[nbr];
                    alphaInfo[own] = alphaInfo0[nbr];
                    infoLocation.ref()[own] = 1;
                    infoLocation.ref()[nbr] = 1;
                    generation[own] = generation0[nbr] + 1;
                }
            }
        }
    }

    return infoLocation;
}


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