/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2011-2016 OpenFOAM Foundation
    Copyright (C) 2017 OpenCFD Ltd.
-------------------------------------------------------------------------------
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/>.

Class
    Foam::surfaceFeatures

Description
    Holds feature edges/points of surface.

    Feature edges are stored in one list and sorted:
        0 .. externalStart_-1               : region edges
        externalStart_ .. internalStart_-1  : external edges
        internalStart_ .. size-1            : internal edges


    NOTE: angle is included angle, not feature angle and is in degrees.
    The included angle is the smallest angle between two planes. For coplanar
    faces it is 180, for straight angles it is 90. To pick up straight edges
    only use included angle of 91 degrees


SourceFiles
    surfaceFeatures.C

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

#ifndef surfaceFeatures_H
#define surfaceFeatures_H

#include "pointField.H"
#include "Map.H"
#include "HashSet.H"
#include "pointIndexHit.H"
#include "edgeList.H"
#include "typeInfo.H"

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

namespace Foam
{

// Forward declaration of classes
class plane;
class triSurface;
class treeBoundBox;

/*---------------------------------------------------------------------------*\
                           Class surfaceFeatures Declaration
\*---------------------------------------------------------------------------*/

class surfaceFeatures
{
public:

        //- Edge status
        enum edgeStatus
        {
            NONE,       //!< Not a classified feature edge
            REGION,     //
            EXTERNAL,   //!< "Convex" edge
            INTERNAL    //!< "Concave" edge
        };


private:

    //- Label and scalar; used in path walking
    class labelScalar
    {
    public:
        label n_;
        scalar len_;

        labelScalar(const label n, const scalar len)
        :
            n_(n),
            len_(len)
        {}
    };

    // Static data

        //- Tolerance for determining whether two vectors are parallel
        static const scalar parallelTolerance;


    // Private data

        //- Reference to surface
        const triSurface& surf_;

        //- Labels of points that are features
        labelList featurePoints_;

        //- Labels of edges that are features
        labelList featureEdges_;

        //- Start of external edges in featureEdges_
        label externalStart_;

        //- Start of internal edges in featureEdges_
        label internalStart_;


    // Private Member Functions

        //- Return nearest point on edge (start..end). Also classify nearest:
        //  index=-1: nearest on mid of edge. index=0:nearest on edge.start()
        //  index=1: nearest on edge.end().
        static pointIndexHit edgeNearest
        (
            const point& start,
            const point& end,
            const point& sample
        );


        //- Construct feature points where more than 2 feature edges meet
        void calcFeatPoints
        (
            const List<edgeStatus>& edgeStat,
            const scalar minCos
        );

        //- Classify the angles of the feature edges
        void classifyFeatureAngles
        (
            const labelListList& edgeFaces,
            List<edgeStatus>& edgeStat,
            const scalar minCos,
            const bool geometricTestOnly
        ) const;

        //- Choose next unset feature edge.
        label nextFeatEdge
        (
            const List<edgeStatus>& edgeStat,
            const labelList& featVisited,
            const label unsetVal,
            const label prevEdgeI,
            const label vertI
        ) const;

        //- Walk connected feature edges. Marks edges in featVisited.
        labelScalar walkSegment
        (
            const bool mark,
            const List<edgeStatus>& edgeStat,
            const label startEdgeI,
            const label startPointi,
            const label currentFeatI,
            labelList& featVisited
        );

        //- Divide into multiple normal bins
        //  - set REGION if != 2 normals
        //  - set REGION if 2 normals that make feature angle
        //  - otherwise set NONE and set normals,bins
        edgeStatus checkFlatRegionEdge
        (
            const scalar tol,
            const scalar includedAngle,
            const label edgeI
        ) const;

public:

    ClassName("surfaceFeatures");

    // Constructors

        //- Construct from surface
        surfaceFeatures(const triSurface& surf);

        //- Construct from components
        surfaceFeatures
        (
            const triSurface& surf,
            const labelList& featurePoints,
            const labelList& featureEdges,
            const label externalStart,
            const label internalStart
        );

        //- Construct from surface, angle and min cumulative length and/or
        //  number of elements. If geometric test only is true, then region
        //  information is ignored and features are only assigned based on the
        //  geometric criteria
        surfaceFeatures
        (
            const triSurface& surf,
            const scalar includedAngle,
            const scalar minLen = 0,
            const label minElems = 0,
            const bool geometricTestOnly = false
        );

        //- Construct from dictionary
        surfaceFeatures(const triSurface& surf, const dictionary& dict);

        //- Construct from file
        surfaceFeatures(const triSurface& surf, const fileName& fName);

        //- Construct from pointField and edgeList (edgeMesh)
        surfaceFeatures
        (
            const triSurface& surf,
            const pointField& points,
            const edgeList& edges,
            const scalar mergeTol = 1e-6,
            const bool geometricTestOnly = false
        );

        //- Construct as copy
        surfaceFeatures(const surfaceFeatures& sf);


    // Member Functions

        // Access

            inline const triSurface& surface() const
            {
                return surf_;
            }

            //- Return feature point list
            inline const labelList& featurePoints() const
            {
                return featurePoints_;
            }

            //- Return feature edge list
            inline const labelList& featureEdges() const
            {
                return featureEdges_;
            }

            //- Start of external edges
            inline label externalStart() const
            {
                return externalStart_;
            }

            //- Start of internal edges
            inline label internalStart() const
            {
                return internalStart_;
            }

            //- Return number of region edges
            inline label nRegionEdges() const
            {
                return externalStart_;
            }

            //- Return number of external edges
            inline label nExternalEdges() const
            {
                return internalStart_ - externalStart_;
            }

            //- Return number of internal edges
            inline label nInternalEdges() const
            {
                return featureEdges_.size() - internalStart_;
            }

            //- Helper function: select a subset of featureEdges_
            labelList selectFeatureEdges
            (
                const bool regionEdges,
                const bool externalEdges,
                const bool internalEdges
            ) const;


        // Edit

            //- Find feature edges using provided included angle
            void findFeatures
            (
                const scalar includedAngle,
                const bool geometricTestOnly
            );

            //- Delete small sets of edges. Edges are stringed up and any
            //  string of length < minLen (or nElems < minElems) is deleted.
            labelList trimFeatures
            (
                const scalar minLen,
                const label minElems,
                const scalar includedAngle
            );

            //- Mark edge status inside box as 'NONE'
            void excludeBox
            (
                List<edgeStatus>& edgeStat,
                const treeBoundBox& bb
            ) const;

            //- Mark edge status outside box as 'NONE'
            void subsetBox
            (
                List<edgeStatus>& edgeStat,
                const treeBoundBox& bb
            ) const;

            //- Mark edge status as 'NONE' for edges inside/outside box.
            void deleteBox
            (
                List<edgeStatus>& edgeStat,
                const treeBoundBox& bb,
                const bool removeInside
            ) const;

            //- If edge does not intersect the plane, mark as 'NONE'
            void subsetPlane
            (
                List<edgeStatus>& edgeStat,
                const plane& cutPlane
            ) const;

            //- Mark edges with a single connected face as 'NONE'
            void excludeOpen(List<edgeStatus>& edgeStat) const;

            //- Divide into multiple normal bins
            //  - set REGION if != 2 normals
            //  - set REGION if 2 normals that make feature angle
            //  - otherwise set NONE and set normals,bins
            void checkFlatRegionEdge
            (
                List<edgeStatus>& edgeStat,
                const scalar tol,
                const scalar includedAngle
            ) const;


            //- From member feature edges to status per edge.
            List<edgeStatus> toStatus() const;

            //- Set from status per edge
            void setFromStatus
            (
                const List<edgeStatus>& edgeStat,
                const scalar includedAngle
            );


        // Find

            //- Find nearest sample for selected surface points
            //  (usually the set of featurePoints). Return map from
            //  index in samples to surface point. Do not include
            //  points that are further than maxDist away (separate
            //  maxDist for every sample).  Supply maxDistSqr.
            Map<label> nearestSamples
            (
                const labelList& selectedPoints,
                const pointField& samples,
                const scalarField& maxDistSqr
            ) const;

            //- Find nearest sample for regularly sampled points along
            //  the selected (surface) edges. Return map from sample
            //  to edge.  maxDistSqr is distance squared below which
            //  gets snapped.  Edge gets sampled at points
            //  sampleDist[sampleI] apart.  (with a maximum of 10
            //  samples per edge)
            Map<label> nearestSamples
            (
                const labelList& selectedEdges,
                const pointField& samples,
                const scalarField& sampleDist,
                const scalarField& maxDistSqr,
                const scalar minSampleDist = 0.1
            ) const;

            //- Like nearestSamples but now gets nearest point on
            //  sample-edge instead of nearest sample-point itself.
            //  Return map from sample edge to feature edge.
            Map<pointIndexHit> nearestEdges
            (
                const labelList& selectedEdges,
                const edgeList& sampleEdges,
                const labelList& selectedSampleEdges,
                const pointField& samplePoints,
                const scalarField& sampleDist,
                const scalarField& maxDistSqr,
                const scalar minSampleDist = 0.1
            ) const;


            //- Find nearest surface edge (out of selectedEdges) for
            //  each sample point.
            //  Sets:
            //  - edgeLabel : label of surface edge.
            //  - edgePoint : exact position of nearest point on edge.
            //  - edgeEndPoint : -1, 0, 1 depending on whether edgePoint is
            //                  on inside/start/end of edge
            void nearestSurfEdge
            (
                const labelList& selectedEdges,
                const pointField& samples,
                scalar searchSpanSqr,   // search span
                labelList& edgeLabel,
                labelList& edgeEndPoint,
                pointField& edgePoint
            ) const;

            //- Find nearest surface edge (out of selectedEdges) for each
            //  sample edge.
            //  Sets:
            //  - edgeLabel         : label of surface edge.
            //  - pointOnEdge       : exact position of nearest point on edge.
            //  - pointOnFeature    : exact position on sample edge.
            void nearestSurfEdge
            (
                const labelList& selectedEdges,
                const edgeList& sampleEdges,
                const labelList& selectedSampleEdges,
                const pointField& samplePoints,
                const vector& searchSpan,   // search span

                labelList& edgeLabel,       // label of surface edge or -1
                pointField& pointOnEdge,    // point on above edge
                pointField& pointOnFeature  // point on sample edge
            ) const;

            //- Find nearest feature edge to each surface edge. Uses the
            //  mid-point of the surface edges.
            void nearestFeatEdge
            (
                const edgeList& edges,
                const pointField& points,
                scalar searchSpanSqr,
                labelList& edgeLabel
            ) const;


        // Write

            //- Write as dictionary
            void writeDict(Ostream& os) const;

            //- Write as dictionary to file
            void write(const fileName& fName) const;

            //- Write to separate OBJ files (region, external, internal edges,
            //  feature points) for visualization
            void writeObj(const fileName& prefix) const;

            //- Write some information
            void writeStats(Ostream& os) const;



    // Member Operators

        void operator=(const surfaceFeatures& rhs);


};


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

} // End namespace Foam

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

#endif

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