/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Copyright (C) 2012-2025 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 "timeVaryingMappedFixedValuePointPatchField.H"
#include "Time.H"
#include "AverageField.H"
#include "IFstream.H"

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

template<class Type>
Foam::timeVaryingMappedFixedValuePointPatchField<Type>::
timeVaryingMappedFixedValuePointPatchField
(
    const pointPatch& p,
    const DimensionedField<Type, pointMesh>& iF,
    const dictionary& dict
)
:
    fixedValuePointPatchField<Type>(p, iF, dict, false),
    fieldTableName_(iF.name()),
    setAverage_(dict.lookupOrDefault("setAverage", false)),
    perturb_(dict.lookupOrDefault("perturb", 1e-5)),
    mapMethod_
    (
        dict.lookupOrDefault<word>
        (
            "mapMethod",
            "planarInterpolation"
        )
    ),
    mapperPtr_(nullptr),
    sampleTimes_(0),
    startSampleTime_(-1),
    startSampledValues_(0),
    startAverage_(Zero),
    endSampleTime_(-1),
    endSampledValues_(0),
    endAverage_(Zero),
    offset_()
{
    if (dict.found("offset"))
    {
        offset_ = Function1<Type>::New
        (
            "offset",
            this->db().time().userUnits(),
            iF.dimensions(),
            dict
        );
    }

    if
    (
        mapMethod_ != "planarInterpolation"
     && mapMethod_ != "nearest"
    )
    {
        FatalIOErrorInFunction
        (
            dict
        )   << "mapMethod should be one of 'planarInterpolation'"
            << ", 'nearest'" << exit(FatalIOError);
    }

    dict.readIfPresent("fieldTableName", fieldTableName_);

    if (dict.found("value"))
    {
        fixedValuePointPatchField<Type>::operator==
        (
            Field<Type>("value", iF.dimensions(), dict, p.size())
        );
    }
    else
    {
        // Note: use evaluate to do updateCoeffs followed by a reset
        //       of the pointPatchField::updated_ flag. This is
        //       so if first use is in the next time step it retriggers
        //       a new update.
        pointPatchField<Type>::evaluate(Pstream::commsTypes::blocking);
    }
}


template<class Type>
Foam::timeVaryingMappedFixedValuePointPatchField<Type>::
timeVaryingMappedFixedValuePointPatchField
(
    const timeVaryingMappedFixedValuePointPatchField<Type>& ptf,
    const pointPatch& p,
    const DimensionedField<Type, pointMesh>& iF,
    const fieldMapper& mapper
)
:
    fixedValuePointPatchField<Type>(ptf, p, iF, mapper),
    fieldTableName_(ptf.fieldTableName_),
    setAverage_(ptf.setAverage_),
    perturb_(ptf.perturb_),
    mapMethod_(ptf.mapMethod_),
    mapperPtr_(nullptr),
    sampleTimes_(0),
    startSampleTime_(-1),
    startSampledValues_(0),
    startAverage_(Zero),
    endSampleTime_(-1),
    endSampledValues_(0),
    endAverage_(Zero),
    offset_(ptf.offset_, false)
{}


template<class Type>
Foam::timeVaryingMappedFixedValuePointPatchField<Type>::
timeVaryingMappedFixedValuePointPatchField
(
    const timeVaryingMappedFixedValuePointPatchField<Type>& ptf,
    const DimensionedField<Type, pointMesh>& iF
)
:
    fixedValuePointPatchField<Type>(ptf, iF),
    fieldTableName_(ptf.fieldTableName_),
    setAverage_(ptf.setAverage_),
    perturb_(ptf.perturb_),
    mapMethod_(ptf.mapMethod_),
    mapperPtr_(ptf.mapperPtr_),
    sampleTimes_(ptf.sampleTimes_),
    startSampleTime_(ptf.startSampleTime_),
    startSampledValues_(ptf.startSampledValues_),
    startAverage_(ptf.startAverage_),
    endSampleTime_(ptf.endSampleTime_),
    endSampledValues_(ptf.endSampledValues_),
    endAverage_(ptf.endAverage_),
    offset_(ptf.offset_, false)
{}


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

template<class Type>
void Foam::timeVaryingMappedFixedValuePointPatchField<Type>::map
(
    const pointPatchField<Type>& ptf,
    const fieldMapper& mapper
)
{
    reset(ptf);
}


template<class Type>
void Foam::timeVaryingMappedFixedValuePointPatchField<Type>::reset
(
    const pointPatchField<Type>& ptf
)
{
    fixedValuePointPatchField<Type>::reset(ptf);

    const timeVaryingMappedFixedValuePointPatchField<Type>& tiptf =
        refCast<const timeVaryingMappedFixedValuePointPatchField<Type>>(ptf);

    startSampledValues_.reset(tiptf.startSampledValues_);
    endSampledValues_.reset(tiptf.endSampledValues_);

    // Clear interpolator
    mapperPtr_.clear();
    startSampleTime_ = -1;
    endSampleTime_ = -1;
}


template<class Type>
void Foam::timeVaryingMappedFixedValuePointPatchField<Type>::checkTable()
{
    // Initialise
    if (startSampleTime_ == -1 && endSampleTime_ == -1)
    {
        const polyMesh& pMesh = this->patch().boundaryMesh().mesh()();

        // Read the initial point position
        pointField meshPts;

        if (pMesh.pointsInstance() == pMesh.facesInstance())
        {
            meshPts = pointField(pMesh.points(), this->patch().meshPoints());
        }
        else
        {
            // Load points from facesInstance
            if (debug)
            {
                Info<< "Reloading points0 from " << pMesh.facesInstance()
                    << endl;
            }

            pointIOField points0
            (
                IOobject
                (
                    "points",
                    pMesh.facesInstance(),
                    polyMesh::meshSubDir,
                    pMesh,
                    IOobject::MUST_READ,
                    IOobject::NO_WRITE,
                    false
                )
            );
            meshPts = pointField(points0, this->patch().meshPoints());
        }

        // Reread values and interpolate
        fileName samplePointsFile
        (
            this->db().time().constant()
           /"boundaryData"
           /this->patch().name()
           /"points"
        );

        pointField samplePoints((IFstream(samplePointsFile)()));

        // tbd: run-time selection
        bool nearestOnly =
        (
           !mapMethod_.empty()
         && mapMethod_ != "planarInterpolation"
        );

        // Allocate the interpolator
        mapperPtr_.reset
        (
            new pointToPointPlanarInterpolation
            (
                samplePoints,
                meshPts,
                perturb_,
                nearestOnly
            )
        );

        // Read the times for which data is available

        const fileName samplePointsDir = samplePointsFile.path();
        sampleTimes_ = this->db().time().findTimes(samplePointsDir);

        if (debug)
        {
            Info<< "timeVaryingMappedFixedValuePointPatchField : In directory "
                << samplePointsDir << " found times "
                << pointToPointPlanarInterpolation::timeNames(sampleTimes_)
                << endl;
        }
    }

    // Find current time in sampleTimes
    label lo = -1;
    label hi = -1;

    bool foundTime = mapperPtr_().findTime
    (
        sampleTimes_,
        startSampleTime_,
        this->db().time().userTimeValue(),
        lo,
        hi
    );

    if (!foundTime)
    {
        FatalErrorInFunction
            << "Cannot find starting sampling values for current time "
            << this->db().time().userTimeValue() << nl
            << "Have sampling values for times "
            << pointToPointPlanarInterpolation::timeNames(sampleTimes_) << nl
            << "In directory "
            <<  this->db().time().constant()/"boundaryData"/this->patch().name()
            << "\n    on patch " << this->patch().name()
            << " of field " << fieldTableName_
            << exit(FatalError);
    }


    // Update sampled data fields.

    if (lo != startSampleTime_)
    {
        startSampleTime_ = lo;

        if (startSampleTime_ == endSampleTime_)
        {
            // No need to reread since are end values
            if (debug)
            {
                Pout<< "checkTable : Setting startValues to (already read) "
                    <<   "boundaryData"
                        /this->patch().name()
                        /sampleTimes_[startSampleTime_].name()
                    << endl;
            }
            startSampledValues_ = endSampledValues_;
            startAverage_ = endAverage_;
        }
        else
        {
            if (debug)
            {
                Pout<< "checkTable : Reading startValues from "
                    <<   "boundaryData"
                        /this->patch().name()
                        /sampleTimes_[lo].name()
                    << endl;
            }

            // Reread values and interpolate
            fileName valsFile
            (
                this->db().time().constant()
               /"boundaryData"
               /this->patch().name()
               /sampleTimes_[startSampleTime_].name()
               /fieldTableName_
            );

            Field<Type> vals;

            if (setAverage_)
            {
                AverageField<Type> avals((IFstream(valsFile)()));
                vals = avals;
                startAverage_ = avals.average();
            }
            else
            {
                (IFstream(valsFile)()) >> vals;
            }

            if (vals.size() != mapperPtr_().sourceSize())
            {
                FatalErrorInFunction
                    << "Number of values (" << vals.size()
                    << ") differs from the number of points ("
                    <<  mapperPtr_().sourceSize()
                    << ") in file " << valsFile << exit(FatalError);
            }

            startSampledValues_ = mapperPtr_().interpolate(vals);
        }
    }

    if (hi != endSampleTime_)
    {
        endSampleTime_ = hi;

        if (endSampleTime_ == -1)
        {
            // endTime no longer valid. Might as well clear endValues.
            if (debug)
            {
                Pout<< "checkTable : Clearing endValues" << endl;
            }
            endSampledValues_.clear();
        }
        else
        {
            if (debug)
            {
                Pout<< "checkTable : Reading endValues from "
                    <<   "boundaryData"
                        /this->patch().name()
                        /sampleTimes_[endSampleTime_].name()
                    << endl;
            }

            // Reread values and interpolate
            fileName valsFile
            (
                this->db().time().constant()
               /"boundaryData"
               /this->patch().name()
               /sampleTimes_[endSampleTime_].name()
               /fieldTableName_
            );

            Field<Type> vals;

            if (setAverage_)
            {
                AverageField<Type> avals((IFstream(valsFile)()));
                vals = avals;
                endAverage_ = avals.average();
            }
            else
            {
                (IFstream(valsFile)()) >> vals;
            }

            if (vals.size() != mapperPtr_().sourceSize())
            {
                FatalErrorInFunction
                    << "Number of values (" << vals.size()
                    << ") differs from the number of points ("
                    <<  mapperPtr_().sourceSize()
                    << ") in file " << valsFile << exit(FatalError);
            }

            endSampledValues_ = mapperPtr_().interpolate(vals);
        }
    }
}


template<class Type>
void Foam::timeVaryingMappedFixedValuePointPatchField<Type>::updateCoeffs()
{
    if (this->updated())
    {
        return;
    }

    checkTable();

    // Interpolate between the sampled data

    Type wantedAverage;

    if (endSampleTime_ == -1)
    {
        // only start value
        if (debug)
        {
            Pout<< "updateCoeffs : Sampled, non-interpolated values"
                << " from start time:"
                << sampleTimes_[startSampleTime_].name() << nl;
        }

        this->operator==(startSampledValues_);
        wantedAverage = startAverage_;
    }
    else
    {
        scalar start = sampleTimes_[startSampleTime_].value();
        scalar end = sampleTimes_[endSampleTime_].value();

        scalar s = (this->db().time().userTimeValue()-start)/(end-start);

        if (debug)
        {
            Pout<< "updateCoeffs : Sampled, interpolated values"
                << " between start time:"
                << sampleTimes_[startSampleTime_].name()
                << " and end time:" << sampleTimes_[endSampleTime_].name()
                << " with weight:" << s << endl;
        }

        this->operator==((1 - s)*startSampledValues_ + s*endSampledValues_);
        wantedAverage = (1 - s)*startAverage_ + s*endAverage_;
    }

    // Enforce average. Either by scaling (if scaling factor > 0.5) or by
    // offsetting.
    if (setAverage_)
    {
        const Field<Type>& fld = *this;

        Type averagePsi = gAverage(fld);

        if (debug)
        {
            Pout<< "updateCoeffs :"
                << " actual average:" << averagePsi
                << " wanted average:" << wantedAverage
                << endl;
        }

        if (mag(averagePsi) < vSmall)
        {
            // Field too small to scale. Offset instead.
            const Type offset = wantedAverage - averagePsi;
            if (debug)
            {
                Pout<< "updateCoeffs :"
                    << " offsetting with:" << offset << endl;
            }
            this->operator==(fld + offset);
        }
        else
        {
            const scalar scale = mag(wantedAverage)/mag(averagePsi);

            if (debug)
            {
                Pout<< "updateCoeffs :"
                    << " scaling with:" << scale << endl;
            }
            this->operator==(scale*fld);
        }
    }

    // Apply offset to mapped values
    if (offset_.valid())
    {
        this->operator==
        (
            *this + offset_->value(this->db().time().value())
        );
    }

    if (debug)
    {
        Pout<< "updateCoeffs : set fixedValue to min:" << gMin(*this)
            << " max:" << gMax(*this)
            << " avg:" << gAverage(*this) << endl;
    }

    fixedValuePointPatchField<Type>::updateCoeffs();
}


template<class Type>
void Foam::timeVaryingMappedFixedValuePointPatchField<Type>::write
(
    Ostream& os
) const
{
    fixedValuePointPatchField<Type>::write(os);

    writeEntryIfDifferent(os, "setAverage", Switch(false), setAverage_);

    writeEntryIfDifferent(os, "perturb", scalar(1e-5), perturb_);

    writeEntryIfDifferent
    (
        os,
        "fieldTable",
        this->internalField().name(),
        fieldTableName_
    );

    writeEntryIfDifferent
    (
        os,
        "mapMethod",
        word("planarInterpolation"),
        mapMethod_
    );

    if (offset_.valid())
    {
        writeEntry(os, offset_());
    }
}


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