/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 1991-2010 OpenCFD Ltd.
     \\/     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 "treeDataCell.H"
#include "indexedOctree.H"
#include <OpenFOAM/primitiveMesh.H>

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

defineTypeNameAndDebug(Foam::treeDataCell, 0);


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

Foam::treeBoundBox Foam::treeDataCell::calcCellBb(const label cellI) const
{
    const cellList& cells = mesh_.cells();
    const faceList& faces = mesh_.faces();
    const pointField& points = mesh_.points();

    treeBoundBox cellBb
    (
        vector(GREAT, GREAT, GREAT),
        vector(-GREAT, -GREAT, -GREAT)
    );

    const cell& cFaces = cells[cellI];

    forAll(cFaces, cFaceI)
    {
        const face& f = faces[cFaces[cFaceI]];

        forAll(f, fp)
        {
            const point& p = points[f[fp]];

            cellBb.min() = min(cellBb.min(), p);
            cellBb.max() = max(cellBb.max(), p);
        }
    }
    return cellBb;
}


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

// Construct from components
Foam::treeDataCell::treeDataCell
(
    const bool cacheBb,
    const primitiveMesh& mesh,
    const labelList& cellLabels
)
:
    mesh_(mesh),
    cellLabels_(cellLabels),
    cacheBb_(cacheBb)
{
    if (cacheBb_)
    {
        bbs_.setSize(cellLabels_.size());

        forAll(cellLabels_, i)
        {
            bbs_[i] = calcCellBb(cellLabels_[i]);
        }
    }
}


Foam::treeDataCell::treeDataCell
(
    const bool cacheBb,
    const primitiveMesh& mesh
)
:
    mesh_(mesh),
    cellLabels_(identity(mesh_.nCells())),
    cacheBb_(cacheBb)
{
    if (cacheBb_)
    {
        bbs_.setSize(cellLabels_.size());

        forAll(cellLabels_, i)
        {
            bbs_[i] = calcCellBb(cellLabels_[i]);
        }
    }
}


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

Foam::pointField Foam::treeDataCell::points() const
{
    pointField cc(cellLabels_.size());

    forAll(cellLabels_, i)
    {
        cc[i] = mesh_.cellCentres()[cellLabels_[i]];
    }

    return cc;
}


// Check if any point on shape is inside cubeBb.
bool Foam::treeDataCell::overlaps
(
    const label index,
    const treeBoundBox& cubeBb
) const
{
    if (cacheBb_)
    {
        return cubeBb.overlaps(bbs_[index]);
    }
    else
    {
        return cubeBb.overlaps(calcCellBb(cellLabels_[index]));
    }
}


// Calculate nearest point to sample. Updates (if any) nearestDistSqr, minIndex,
// nearestPoint.
void Foam::treeDataCell::findNearest
(
    const labelList& indices,
    const point& sample,

    scalar& nearestDistSqr,
    label& minIndex,
    point& nearestPoint
) const
{
    forAll(indices, i)
    {
        label index = indices[i];
        label cellI = cellLabels_[index];
        scalar distSqr = magSqr(sample - mesh_.cellCentres()[cellI]);

        if (distSqr < nearestDistSqr)
        {
            nearestDistSqr = distSqr;
            minIndex = index;
            nearestPoint = mesh_.cellCentres()[cellI];
        }
    }
}


bool Foam::treeDataCell::intersects
(
    const label index,
    const point& start,
    const point& end,
    point& intersectionPoint
) const
{
    // Do quick rejection test
    if (cacheBb_)
    {
        const treeBoundBox& cellBb = bbs_[index];

        if ((cellBb.posBits(start) & cellBb.posBits(end)) != 0)
        {
            // start and end in same block outside of cellBb.
            return false;
        }
    }
    else
    {
        const treeBoundBox cellBb = calcCellBb(cellLabels_[index]);

        if ((cellBb.posBits(start) & cellBb.posBits(end)) != 0)
        {
            // start and end in same block outside of cellBb.
            return false;
        }
    }


    // Do intersection with all faces of cell
    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    // Disable picking up intersections behind us.
    scalar oldTol = intersection::setPlanarTol(0.0);

    const cell& cFaces = mesh_.cells()[cellLabels_[index]];

    const vector dir(end - start);
    scalar minDistSqr = magSqr(dir);
    bool hasMin = false;

    forAll(cFaces, i)
    {
        const face& f = mesh_.faces()[cFaces[i]];

        pointHit inter = f.ray
        (
            start,
            dir,
            mesh_.points(),
            intersection::HALF_RAY
        );

        if (inter.hit() && sqr(inter.distance()) <= minDistSqr)
        {
            // Note: no extra test on whether intersection is in front of us
            // since using half_ray AND zero tolerance. (note that tolerance
            // is used to look behind us)
            minDistSqr = sqr(inter.distance());
            intersectionPoint = inter.hitPoint();
            hasMin = true;
        }
    }

    // Restore picking tolerance
    intersection::setPlanarTol(oldTol);

    return hasMin;
}


// ************************ vim: set sw=4 sts=4 et: ************************ //
