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

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

template
<
    class Face,
    template<class> class FaceList,
    class PointField,
    class PointType
>

bool
Foam::PatchTools::checkOrientation
(
    const PrimitivePatch<Face, FaceList, PointField, PointType>& p,
    const bool report,
    labelHashSet* setPtr
)
{
    bool foundError = false;

    // Check edge normals, face normals, point normals.
    forAll(p.faceEdges(), faceI)
    {
        const labelList& edgeLabels = p.faceEdges()[faceI];
        bool valid = true;

        if (edgeLabels.size() < 3)
        {
            if (report)
            {
                Info<< "Face[" << faceI << "] " << p[faceI]
                    << " has fewer than 3 edges. Edges: " << edgeLabels
                    << endl;
            }
            valid = false;
        }
        else
        {
            forAll(edgeLabels, i)
            {
                if (edgeLabels[i] < 0 || edgeLabels[i] >= p.nEdges())
                {
                    if (report)
                    {
                        Info<< "edge number " << edgeLabels[i]
                            << " on face " << faceI
                            << " out-of-range\n"
                            << "This usually means the input surface has "
                            << "edges with more than 2 faces connected."
                            << endl;
                    }
                    valid = false;
                }
            }
        }

        if (!valid)
        {
            foundError = true;
            continue;
        }


        //
        //- Compute normal from 3 points, use the first as the origin
        // minor warpage should not be a problem
        const Face& f = p[faceI];
        const point& p0 = p.points()[f[0]];
        const point& p1 = p.points()[f[1]];
        const point& p2 = p.points()[f.last()];

        const vector pointNormal((p1 - p0) ^ (p2 - p0));
        if ((pointNormal & p.faceNormals()[faceI]) < 0)
        {
            foundError = false;

            if (report)
            {
                Info
                    << "Normal calculated from points inconsistent"
                    << " with faceNormal" << nl
                    << "face: " << f << nl
                    << "points: " << p0 << ' ' << p1 << ' ' << p2 << nl
                    << "pointNormal:" << pointNormal << nl
                    << "faceNormal:" << p.faceNormals()[faceI] << endl;
            }
        }
    }


    forAll(p.edges(), edgeI)
    {
        const edge& e = p.edges()[edgeI];
        const labelList& neighbouringFaces = p.edgeFaces()[edgeI];

        if (neighbouringFaces.size() == 2)
        {
            // we use localFaces() since edges() are LOCAL
            // these are both already available
            const Face& faceA = p.localFaces()[neighbouringFaces[0]];
            const Face& faceB = p.localFaces()[neighbouringFaces[1]];

            // If the faces are correctly oriented, the edges must go in
            // different directions on connected faces.
            if (faceA.edgeDirection(e) == faceB.edgeDirection(e))
            {
                if (report)
                {
                    Info<< "face orientation incorrect." << nl
                        << "localEdge[" << edgeI << "] " << e
                        << " between faces:" << nl
                        << "  face[" << neighbouringFaces[0] << "] "
                        << p[neighbouringFaces[0]]
                        << "   localFace: " << faceA
                        << nl
                        << "  face[" << neighbouringFaces[1] << "] "
                        << p[neighbouringFaces[1]]
                        << "   localFace: " << faceB
                        << endl;
                }
                if (setPtr)
                {
                    setPtr->insert(edgeI);
                }

                foundError = true;
            }
        }
        else if (neighbouringFaces.size() != 1)
        {
            if (report)
            {
                Info
                    << "Wrong number of edge neighbours." << nl
                    << "edge[" << edgeI << "] " << e
                    << " with points:" << p.localPoints()[e.start()]
                    << ' ' << p.localPoints()[e.end()]
                    << " has neighbouringFaces:" << neighbouringFaces << endl;
            }

            if (setPtr)
            {
                setPtr->insert(edgeI);
            }

            foundError = true;
        }
    }

    return foundError;
}


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