/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2005-2006 Refractions Research Inc.
 * Copyright (C) 2001-2002 Vivid Solutions Inc.
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Public Licence as published
 * by the Free Software Foundation.
 * See the COPYING file for more information.
 *
 **********************************************************************
 *
 * Last port: geomgraph/Label.java r428 (JTS-1.12+)
 *
 **********************************************************************/


#pragma once

#include <geos/export.h>
#include <geos/geom/Location.h>
#include <geos/geomgraph/TopologyLocation.h>

#include <iosfwd> // for operator<<
#include <cassert>

namespace geos {
namespace geomgraph { // geos.geomgraph

/** \brief
 * A <code>Label</code> indicates the topological relationship of a component
 * of a topology graph to a given <code>Geometry</code>.
 *
 * This class supports labels for relationships to two <code>Geometry</code>s,
 * which is sufficient for algorithms for binary operations.
 *
 * Topology graphs support the concept of labeling nodes and edges in the graph.
 * The label of a node or edge specifies its topological relationship to one or
 * more geometries.  (In fact, since JTS operations have only two arguments labels
 * are required for only two geometries).  A label for a node or edge has one or
 * two elements, depending on whether the node or edge occurs in one or both of the
 * input <code>Geometry</code>s.  Elements contain attributes which categorize the
 * topological location of the node or edge relative to the parent
 * <code>Geometry</code>; that is, whether the node or edge is in the interior,
 * boundary or exterior of the <code>Geometry</code>.  Attributes have a value
 * from the set <code>{Interior, Boundary, Exterior}</code>.  In a node each
 * element has  a single attribute <code>&lt;On&gt;</code>.  For an edge each element has a
 * triplet of attributes <code>&lt;Left, On, Right&gt;</code>.
 *
 * It is up to the client code to associate the 0 and 1 <code>TopologyLocation</code>s
 * with specific geometries.
 *
 */
class GEOS_DLL Label final {
    using Position = geos::geom::Position;

public:

    friend std::ostream& operator<< (std::ostream&, const Label&);

    /** \brief
     * Converts a Label to a Line label
     * (that is, one with no side Locations)
     *
     */
    static Label toLineLabel(const Label& label)
    {
        Label lineLabel(geom::Location::NONE);
        for(uint32_t i = 0; i < 2; i++) {
            lineLabel.setLocation(i, label.getLocation(i));
        }
        return lineLabel;
    };

    /** \brief
     * Construct a Label with a single location for both Geometries.
     */
    Label(geom::Location onLoc)
        : elt{TopologyLocation(onLoc)
        , TopologyLocation(onLoc)}
        {};

    /** \brief
     * Construct a Label with the location specified
     * for the given Geometry.
     *
     * Other geometry location will be set to
     * Location::NONE.
     */
    Label(uint32_t geomIndex, geom::Location onLoc)
        : elt{TopologyLocation(geom::Location::NONE)
        , TopologyLocation(geom::Location::NONE)}
    {
        assert(geomIndex < 2);
        elt[geomIndex].setLocation(onLoc);
    };

    /** \brief
     * Construct a Label with On, Left and Right locations for both Geometries.
     *
     * Initialize the locations for both Geometries to the given values.
     */
    Label(geom::Location onLoc, geom::Location leftLoc, geom::Location rightLoc)
        : elt {TopologyLocation(onLoc, leftLoc, rightLoc)
        , TopologyLocation(onLoc, leftLoc, rightLoc)}
        {};

    /// Copy ctor
    Label(const Label& l)
        : elt{TopologyLocation(l.elt[0])
        , TopologyLocation(l.elt[1])}
        {};

    /** \brief
     * Initialize both locations to Location::NONE
     *
     * isNull() should return true after this kind of construction
     */
    Label()
        : elt{TopologyLocation(geom::Location::NONE)
        , TopologyLocation(geom::Location::NONE)}
        {};

    /** \brief
     * Construct a Label with On, Left and Right locations for the
     * given Geometries.
     * Initialize the locations for the other Geometry to
     * Location::NONE
     */
    Label(uint32_t geomIndex, geom::Location onLoc, geom::Location leftLoc, geom::Location rightLoc)
    {
        elt[0] = TopologyLocation(geom::Location::NONE, geom::Location::NONE, geom::Location::NONE);
        elt[1] = TopologyLocation(geom::Location::NONE, geom::Location::NONE, geom::Location::NONE);
        elt[geomIndex].setLocations(onLoc, leftLoc, rightLoc);
    };

    Label&
    operator=(const Label& l)
    {
        elt[0] = TopologyLocation(l.elt[0]);
        elt[1] = TopologyLocation(l.elt[1]);
        return *this;
    };

    void flip()
    {
        elt[0].flip();
        elt[1].flip();
    };

    /** \brief
     * Merge this label with another one.
     *
     * Merging updates any null attributes of this label with the attributes
     * from lbl
     */
    void merge(const Label& lbl)
    {
        for(int i = 0; i < 2; i++) {
            elt[i].merge(lbl.elt[i]);
        }
    };

    int getGeometryCount() const
    {
        int count = 0;
        if(!elt[0].isNull()) {
            count++;
        }
        if(!elt[1].isNull()) {
            count++;
        }
        return count;
    };

    geom::Location getLocation(uint32_t geomIndex, uint32_t posIndex) const
    {
        assert(geomIndex < 2);
        return elt[geomIndex].get(posIndex);
    };

    geom::Location getLocation(uint32_t geomIndex) const
    {
        assert(geomIndex < 2);
        return elt[geomIndex].get(Position::ON);
    };

    void setLocation(uint32_t geomIndex, uint32_t posIndex, geom::Location location)
    {
        assert(geomIndex < 2);
        elt[geomIndex].setLocation(posIndex, location);
    };

    void setLocation(uint32_t geomIndex, geom::Location location)
    {
        assert(geomIndex < 2);
        elt[geomIndex].setLocation(Position::ON, location);
    };

    void setAllLocations(uint32_t geomIndex, geom::Location location)
    {
        assert(geomIndex < 2);
        elt[geomIndex].setAllLocations(location);
    };

    void setAllLocationsIfNull(uint32_t geomIndex, geom::Location location)
    {
        assert(geomIndex < 2);
        elt[geomIndex].setAllLocationsIfNull(location);
    };

    void setAllLocationsIfNull(geom::Location location)
    {
        setAllLocationsIfNull(0, location);
        setAllLocationsIfNull(1, location);
    };

    bool isNull(uint32_t geomIndex) const
    {
        assert(geomIndex < 2);
        return elt[geomIndex].isNull();
    };

    bool isNull() const
    {
        return elt[0].isNull() && elt[1].isNull();
    };

    bool isAnyNull(uint32_t geomIndex) const
    {
        assert(geomIndex < 2);
        return elt[geomIndex].isAnyNull();
    };

    bool isArea() const
    {
        return elt[0].isArea() || elt[1].isArea();
    };

    bool isArea(uint32_t geomIndex) const
    {
        assert(geomIndex < 2);
        return elt[geomIndex].isArea();
    };

    bool isLine(uint32_t geomIndex) const
    {
        assert(geomIndex < 2);
        return elt[geomIndex].isLine();
    };

    bool isEqualOnSide(const Label& lbl, uint32_t side) const
    {
        return elt[0].isEqualOnSide(lbl.elt[0], side)
                && elt[1].isEqualOnSide(lbl.elt[1], side);
    };

    bool allPositionsEqual(uint32_t geomIndex, geom::Location loc) const
    {
        assert(geomIndex < 2);
        return elt[geomIndex].allPositionsEqual(loc);
    };

    /** \brief
     * Converts one GeometryLocation to a Line location
     */
    void toLine(uint32_t geomIndex)
    {
        assert(geomIndex < 2);
        if(elt[geomIndex].isArea()) {
            elt[geomIndex] = TopologyLocation(elt[geomIndex].getLocations()[0]);
        }
    };

    std::string toString() const;

private:

    TopologyLocation elt[2];

};

std::ostream& operator<< (std::ostream&, const Label&);

} // namespace geos.geomgraph
} // namespace geos


