/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 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 "histogram.H"
#include "volFields.H"

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

namespace Foam
{
namespace functionObjects
{
    defineTypeNameAndDebug(histogram, 0);
}
}


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

void Foam::functionObjects::histogram::writeGraph
(
    const coordSet& coords,
    const word& fieldName,
    const scalarField& values
) const
{
    const wordList fieldNames(1, fieldName);

    fileName outputPath = baseTimeDir();
    mkDir(outputPath);
    OFstream graphFile
    (
        outputPath/formatterPtr_().getFileName(coords, fieldNames)
    );

    Info<< "Writing histogram of " << fieldName
        << " to " << graphFile.name() << endl;

    List<const scalarField*> yPtrs(1);
    yPtrs[0] = &values;
    formatterPtr_().write(coords, fieldNames, yPtrs, graphFile);
}


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

Foam::functionObjects::histogram::histogram
(
    const word& name,
    const objectRegistry& obr,
    const dictionary& dict,
    const bool loadFromFiles
)
:
    functionObjectFile(obr, typeName),
    name_(name),
    active_(true)
{
    // Check if the available mesh is an fvMesh, otherwise deactivate
    if (isA<fvMesh>(obr_))
    {
        read(dict);
    }
    else
    {
        active_ = false;
        WarningInFunction
            << "No fvMesh available, deactivating " << name_ << nl
            << endl;
    }
}


Foam::autoPtr<Foam::functionObjects::histogram>
Foam::functionObjects::histogram::New
(
    const word& name,
    const objectRegistry& obr,
    const dictionary& dict,
    const bool loadFromFiles
)
{
    if (isA<fvMesh>(obr))
    {
        return autoPtr<histogram>
        (
            new histogram(name, obr, dict, loadFromFiles)
        );
    }
    else
    {
        return autoPtr<histogram>();
    }
}


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

Foam::functionObjects::histogram::~histogram()
{}


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

void Foam::functionObjects::histogram::read(const dictionary& dict)
{
    if (active_)
    {
        dict.lookup("field") >> fieldName_;
        dict.lookup("max") >> max_;
        min_ = dict.lookupOrDefault<scalar>("min", 0);
        dict.lookup("nBins") >> nBins_;

        word format(dict.lookup("setFormat"));
        formatterPtr_ = writer<scalar>::New(format);
    }
}


void Foam::functionObjects::histogram::execute()
{}


void Foam::functionObjects::histogram::end()
{}


void Foam::functionObjects::histogram::timeSet()
{}


void Foam::functionObjects::histogram::write()
{
    if (active_)
    {
        Info<< type() << " " << name_ << " output:" << nl;

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

        autoPtr<volScalarField> fieldPtr;
        if (obr_.foundObject<volScalarField>(fieldName_))
        {
            Info<< "    Looking up field " << fieldName_ << endl;
        }
        else
        {
            Info<< "    Reading field " << fieldName_ << endl;
            fieldPtr.reset
            (
                new volScalarField
                (
                    IOobject
                    (
                        fieldName_,
                        mesh.time().timeName(),
                        mesh,
                        IOobject::MUST_READ,
                        IOobject::NO_WRITE
                    ),
                    mesh
                )
            );
        }

        const volScalarField& field =
        (
             fieldPtr.valid()
           ? fieldPtr()
           : obr_.lookupObject<volScalarField>(fieldName_)
        );

        // Calculate the mid-points of bins for the graph axis
        pointField xBin(nBins_);
        const scalar delta = (max_- min_)/nBins_;

        scalar x = min_ + 0.5*delta;
        forAll(xBin, i)
        {
            xBin[i] = point(x, 0, 0);
            x += delta;
        }

        scalarField volFrac(nBins_, 0);
        const scalarField& V = mesh.V();

        forAll(field, celli)
        {
            const label bini = (field[celli] - min_)/delta;
            if (bini >= 0 && bini < nBins_)
            {
                volFrac[bini] += V[celli];
            }
        }

        Pstream::listCombineGather(volFrac, plusEqOp<scalar>());

        if (Pstream::master())
        {
            const scalar sumVol = sum(volFrac);

            if (sumVol > SMALL)
            {
                volFrac /= sumVol;

                const coordSet coords
                (
                    "Volume_Fraction",
                    "x",
                    xBin,
                    mag(xBin)
                );

                writeGraph(coords, field.name(), volFrac);
            }
        }
    }
}


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