/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2016 OpenFOAM Foundation
    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 "equalBinWidth.H"
#include "histogramModel.H"
#include "addToRunTimeSelectionTable.H"

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

namespace Foam
{
namespace histogramModels
{
    defineTypeNameAndDebug(equalBinWidth, 0);
    addToRunTimeSelectionTable(histogramModel, equalBinWidth, dictionary);
}
}


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

Foam::histogramModels::equalBinWidth::equalBinWidth
(
    const word& name,
    const fvMesh& mesh,
    const dictionary& dict
)
:
    histogramModel(name, mesh, dict),
    nBins_(0),
    range_()
{
    read(dict);
}


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

bool Foam::histogramModels::equalBinWidth::read(const dictionary& dict)
{
    if (!histogramModel::read(dict))
    {
        return false;
    }

    range_.reset
    (
        dict.getOrDefault<scalar>("min", GREAT),
        dict.getOrDefault<scalar>("max", -GREAT)
    );

    nBins_ = dict.get<scalar>("nBins");

    if (nBins_ < 1)
    {
        FatalIOErrorInFunction(dict)
            << "Number of histogram bins = " << nBins_
            << " cannot be negative or zero."
            << abort(FatalIOError);
    }

    return true;
}


bool Foam::histogramModels::equalBinWidth::write(const bool log)
{
    // Retrieve operand field
    const volScalarField& field = histogramModel::getOrReadField(fieldName());

    // Determine min and max from the operand field
    // if the user did not provide any min or max

    scalarMinMax histRange(range_);

    if (histRange.max() == -GREAT)
    {
        histRange.max() = max(field).value();

        if (histRange.min() == GREAT)
        {
            histRange.min() = min(field).value();
        }

        if (log)
        {
            Info<< "    Determined histogram bounds from field"
                << " min/max(" << fieldName() << ") = "
                << histRange << endl;
        }
    }
    else if (histRange.min() == GREAT)
    {
        histRange.min() = Zero;
    }

    if (!histRange.good())
    {
        FatalErrorInFunction
            << "Invalid histogram range: " << histRange
            << exit(FatalError);
    }


    // Calculate the mid-points of bins for the graph axis
    pointField binMidPoints(nBins_, Zero);
    const scalar delta = histRange.span()/nBins_;

    {
        scalar x = histRange.min() + 0.5*delta;
        for (point& p : binMidPoints)
        {
            p.x() = x;
            x += delta;
        }
    }


    // Calculate the histogram data
    scalarField dataNormalised(nBins_, Zero);
    labelField dataCount(nBins_, Zero);
    const scalarField& V = mesh().V();

    forAll(field, celli)
    {
        const label bini = (field[celli] - histRange.min())/delta;
        if (bini >= 0 && bini < nBins_)
        {
            dataNormalised[bini] += V[celli];
            dataCount[bini]++;
        }
    }
    Pstream::listGather(dataNormalised, sumOp<scalar>());
    Pstream::listGather(dataCount, sumOp<label>());


    // Write histogram data
    histogramModel::write(dataNormalised, dataCount, mag(binMidPoints));

    return true;
}


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