/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011-2013 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/>.

\*---------------------------------------------------------------------------*/

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

inline Foam::pointConstraint::pointConstraint()
:
    Tuple2<label, vector>(0, vector::zero)
{}


inline Foam::pointConstraint::pointConstraint(const Tuple2<label, vector>& pc)
:
    Tuple2<label, vector>(pc)
{}


inline Foam::pointConstraint::pointConstraint(Istream& is)
:
    Tuple2<label, vector>(is)
{}


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

void Foam::pointConstraint::applyConstraint(const vector& cd)
{
    if (first() == 0)
    {
        first() = 1;
        second() = cd;
    }
    else if (first() == 1)
    {
        vector planeNormal = cd ^ second();
        scalar magPlaneNormal = mag(planeNormal);

        if (magPlaneNormal > 1e-3)
        {
            first() = 2;
            second() = planeNormal/magPlaneNormal;
        }
    }
    else if (first() == 2)
    {
        if (mag(cd & second()) > 1e-3)
        {
            first() = 3;
            second() = vector::zero;
        }
    }
}


void Foam::pointConstraint::combine(const pointConstraint& pc)
{
    if (first() == 0)
    {
        operator=(pc);
    }
    else if (first() == 1)
    {
        // Save single normal
        vector n = second();
        // Apply to supplied point constaint
        operator=(pc);
        applyConstraint(n);
    }
    else if (first() == 2)
    {
        if (pc.first() == 0)
        {}
        else if (pc.first() == 1)
        {
            applyConstraint(pc.second());
        }
        else if (pc.first() == 2)
        {
            // Both constrained to line. Same (+-)direction?
            if (mag(second() & pc.second()) <= (1.0-1e-3))
            {
                // Different directions
                first() = 3;
                second() = vector::zero;
            }
        }
        else
        {
            first() = 3;
            second() = vector::zero;
        }
    }
}


Foam::tensor Foam::pointConstraint::constraintTransformation() const
{
    if (first() == 0)
    {
        return I;
    }
    else if (first() == 1)
    {
        return I - sqr(second());
    }
    else if (first() == 2)
    {
        return sqr(second());
    }
    else
    {
        return tensor::zero;
    }
}


void Foam::pointConstraint::unconstrainedDirections(label& n, tensor& tt)
const
{
    n = 3-first();

    FixedList<vector, 3> vecs;

    if (first() == 0)
    {
        vecs[0] = vector(1, 0, 0);
        vecs[1] = vector(0, 1, 0);
        vecs[2] = vector(0, 0, 1);
    }
    else if (first() == 1)
    {
        const vector& planeDir = second();

        vecs[0] = vector(1, 0, 0) - planeDir.x()*planeDir;

        if (mag(vecs[0].x()) < 1e-3)
        {
            vecs[0] = vector(0, 1, 0) - planeDir.y()*planeDir;
        }

        vecs[0] /= mag(vecs[0]);
        vecs[1] = vecs[0] ^ planeDir;
        vecs[1] /= mag(vecs[1]);
    }
    else if (first() == 2)
    {
        vecs[0] = second();
    }

    // Knock out remaining vectors
    for (direction dir = n; dir < vecs.size(); dir++)
    {
        vecs[dir] = vector::zero;
    }

    tt = tensor(vecs[0], vecs[1], vecs[2]);
}


void Foam::combineConstraintsEqOp::operator()
(
    pointConstraint& x,
    const pointConstraint& y
) const
{
    x.combine(y);
}


Foam::pointConstraint Foam::transform
(
    const tensor& tt,
    const pointConstraint& v
)
{
    return pointConstraint
    (
        Tuple2<label, vector>(v.first(), transform(tt, v.second()))
    );
}


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