/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2016-2022 OpenCFD Ltd.
-------------------------------------------------------------------------------
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 "polyPatch.H"
#include "Time.H"
#include "zeroGradientFvPatchField.H"

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

template<class Type>
bool Foam::functionObjects::zeroGradient::accept
(
    const GeometricField<Type, fvPatchField, volMesh>& input
)
{
    const auto& patches = input.boundaryField();

    forAll(patches, patchi)
    {
        if (!polyPatch::constraintType(patches[patchi].patch().patch().type()))
        {
            return true;
        }
    }

    return false;
}


template<class Type>
int Foam::functionObjects::zeroGradient::apply
(
    const word& inputName,
    int& state
)
{
    typedef GeometricField<Type, fvPatchField, volMesh> VolFieldType;

    // State: return 0 (not-processed), -1 (skip), +1 ok

    // Already done, or not available
    if (state || !foundObject<VolFieldType>(inputName))
    {
        return state;
    }

    const VolFieldType& input = lookupObject<VolFieldType>(inputName);

    if (!returnReduceOr(accept(input)))
    {
        state = -1;
        return state;
    }

    word outputName(resultName_);
    outputName.replace("@@", inputName);

    // Also save the field-type, just in case we want it later
    results_.set(outputName, VolFieldType::typeName);

    if (!foundObject<VolFieldType>(outputName))
    {
        auto tzeroGrad = tmp<VolFieldType>::New
        (
            IOobject
            (
                outputName,
                time_.timeName(),
                mesh_,
                IOobject::NO_READ,
                IOobject::NO_WRITE
            ),
            mesh_,
            dimensioned<Type>(input.dimensions(), Zero),
            fvPatchFieldBase::zeroGradientType()
        );

        store(outputName, tzeroGrad);
    }

    VolFieldType& output = lookupObjectRef<VolFieldType>(outputName);

    output = input;
    output.correctBoundaryConditions();

    state = +1;
    return state;
}


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