/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2011-2016 OpenFOAM Foundation
    Copyright (C) 2019 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 "bufferedAccumulator.H"

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

template<class Type>
const char* const
    Foam::bufferedAccumulator<Type>::typeName("bufferedAccumulator");


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

template<class Type>
void Foam::bufferedAccumulator<Type>::accumulateAndResetBuffer(const label b)
{
    accumulationBuffer() += (*this)[b];

    averagesTaken_++;

    (*this)[b] = Field<Type>(bufferLength(), Zero);

    bufferOffsets_[b] = 0;
}


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

template<class Type>
Foam::bufferedAccumulator<Type>::bufferedAccumulator()
:
    List<Field<Type>>(),
    averagesTaken_(),
    bufferOffsets_()
{}


template<class Type>
Foam::bufferedAccumulator<Type>::bufferedAccumulator
(
    const label nBuffers,
    const label bufferLength,
    const label bufferingInterval
)
:
    List<Field<Type>>(),
    averagesTaken_(),
    bufferOffsets_()
{
    setSizes
    (
        nBuffers,
        bufferLength,
        bufferingInterval
    );
}


template<class Type>
Foam::bufferedAccumulator<Type>::bufferedAccumulator
(
    const bufferedAccumulator<Type>& bA
)
:
    List<Field<Type>>(static_cast<List<Field<Type>>>(bA)),
    averagesTaken_(bA.averagesTaken()),
    bufferOffsets_(bA.bufferOffsets())
{}


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

template<class Type>
Foam::bufferedAccumulator<Type>::~bufferedAccumulator()
{}


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

template<class Type>
void Foam::bufferedAccumulator<Type>::setSizes
(
    const label nBuffers,
    const label bufferLength,
    const label bufferingInterval
)
{
    (*this).setSize(nBuffers + 1);

    forAll((*this), b)
    {
        (*this)[b] = Field<Type>(bufferLength, Zero);
    }

    averagesTaken_ = 0;

    bufferOffsets_.setSize(nBuffers);

    forAll(bufferOffsets_, bO)
    {
        bufferOffsets_[bO] = -bufferingInterval * bO - 1;
    }
}


template<class Type>
Foam::label Foam::bufferedAccumulator<Type>::addToBuffers
(
    const List<Type>& valuesToAdd
)
{
    label bufferToRefill = -1;

    for (label b = 0; b < nBuffers(); b++)
    {
        Field<Type>& buf((*this)[b]);

        label& bO = bufferOffsets_[b];

        if (bO >= 0)
        {
            buf[bO] = valuesToAdd[b];
        }

        bO++;

        if (bO == bufferLength())
        {
            accumulateAndResetBuffer(b);
        }

        if (bO == 0)
        {
            if (bufferToRefill != -1)
            {
                FatalErrorInFunction
                    << "More than one bufferedAccumulator accumulation "
                    << "buffer filled at once, this is considered an error."
                    << abort(FatalError);
            }

            bufferToRefill = b;
        }
    }

    return bufferToRefill;
}


template<class Type>
Foam::Field<Type> Foam::bufferedAccumulator<Type>::averaged() const
{
    if (averagesTaken_)
    {
        Field<Type> bA = accumulationBuffer()/averagesTaken_;

        return bA;
    }
    else
    {
        WarningInFunction
            << "Averaged correlation function requested but averagesTaken = "
            << averagesTaken_
            << ". Returning empty field."
            << endl;

        return Field<Type>(bufferLength(), Zero);
    }
}


template<class Type>
void Foam::bufferedAccumulator<Type>::resetAveraging()
{
    accumulationBuffer() = Field<Type>(bufferLength(), Zero);

    averagesTaken_ = 0;
}


// * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //

template<class Type>
void Foam::bufferedAccumulator<Type>::operator=
(
    const bufferedAccumulator<Type>& rhs
)
{
    if (this == &rhs)
    {
        return;  // Self-assignment is a no-op
    }

    List<Field<Type>>::operator=(rhs);

    averagesTaken_ = rhs.averagesTaken();

    bufferOffsets_ = rhs.bufferOffsets();
}


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

#include "bufferedAccumulatorIO.C"

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