/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Copyright (C) 2011-2019 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 FaceList, class PointField>
Foam::labelListList Foam::PatchTools::sortedPointEdges
(
    const PrimitivePatch<FaceList, PointField>& p
)
{
    // Now order the edges of each point according to whether they share a
    // face
    const labelListList& pointEdges = p.pointEdges();
    const edgeList& edges = p.edges();
    const labelListList& edgeFaces = p.edgeFaces();
    const labelListList& faceEdges = p.faceEdges();

    // create the lists for the various results. (resized on completion)
    labelListList sortedPointEdges(pointEdges);

    DynamicList<label> newEdgeList;

    forAll(pointEdges, pointi)
    {
        const labelList& pEdges = pointEdges[pointi];

        label nPointEdges = pEdges.size();

        label edgeI = pEdges[0];

        label prevFacei = edgeFaces[edgeI][0];

        newEdgeList.clear();
        newEdgeList.setCapacity(nPointEdges);

        label nVisitedEdges = 0;

        do
        {
            newEdgeList.append(edgeI);

            // Cross edge to next face
            const labelList& eFaces = edgeFaces[edgeI];

            if (eFaces.size() != 2)
            {
                break;
            }

            label facei = eFaces[0];
            if (facei == prevFacei)
            {
                facei = eFaces[1];
            }

            // Cross face to next edge
            const labelList& fEdges = faceEdges[facei];

            forAll(fEdges, feI)
            {
                const label nextEdgeI = fEdges[feI];
                const edge& nextEdge = edges[nextEdgeI];

                if
                (
                    nextEdgeI != edgeI
                 && (nextEdge.start() == pointi || nextEdge.end() == pointi)
                )
                {
                    edgeI = nextEdgeI;
                    break;
                }
            }

            prevFacei = facei;

            nVisitedEdges++;
            if (nVisitedEdges > nPointEdges)
            {
                WarningInFunction
                    << "Unable to order pointEdges as the face connections "
                    << "are not circular" << nl
                    << "    Original pointEdges = " << pEdges << nl
                    << "    New pointEdges = " << newEdgeList
                    << endl;

                newEdgeList = pEdges;

                break;
            }

        } while (edgeI != pEdges[0]);

        if (newEdgeList.size() == nPointEdges)
        {
            forAll(pEdges, eI)
            {
                if (findIndex(newEdgeList, pEdges[eI]) == -1)
                {
                    WarningInFunction
                        << "Cannot find all original edges in the new list"
                        << nl
                        << "    Original pointEdges = " << pEdges << nl
                        << "    New pointEdges = " << newEdgeList
                        << endl;

                    newEdgeList = pEdges;

                    break;
                }
            }

            sortedPointEdges[pointi] = newEdgeList;
        }
    }

    return sortedPointEdges;
}


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