/**********************************************************************
 * $Id: DirectedEdge.h 2557 2009-06-08 09:30:55Z strk $
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.refractions.net
 *
 * 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/DirectedEdge.java rev. 1.5 (JTS-1.10)
 *
 **********************************************************************/


#ifndef GEOS_GEOMGRAPH_DIRECTEDEDGE_H
#define GEOS_GEOMGRAPH_DIRECTEDEDGE_H

#include <geos/export.h>
#include <string>

#include <geos/geomgraph/EdgeEnd.h> // for inheritance

#include <geos/inline.h>

// Forward declarations
namespace geos {
	namespace geomgraph {
		class Edge;
		class EdgeRing;
	}
}

namespace geos {
namespace geomgraph { // geos.geomgraph

/// A directed EdgeEnd
class GEOS_DLL DirectedEdge: public EdgeEnd {

public:

	/** \brief
	 * Computes the factor for the change in depth when moving from
	 * one location to another.
	 * E.g. if crossing from the INTERIOR to the EXTERIOR the depth
	 * decreases, so the factor is -1
	 */
	static int depthFactor(int currLocation, int nextLocation);

	//DirectedEdge();	
	//virtual ~DirectedEdge();	

	DirectedEdge(Edge *newEdge, bool newIsForward);

	// this is no different from Base class, no need to override
	//Edge* getEdge();

	void setInResult(bool newIsInResult);

	bool isInResult();

	bool isVisited();

	void setVisited(bool newIsVisited);

	void setEdgeRing(EdgeRing *newEdgeRing);

	EdgeRing* getEdgeRing();

	void setMinEdgeRing(EdgeRing *newMinEdgeRing);

	EdgeRing* getMinEdgeRing();

	int getDepth(int position);

	void setDepth(int position, int newDepth);

	int getDepthDelta();

	/// Marks both DirectedEdges attached to a given Edge.
	//
	/// This is used for edges corresponding to lines, which will only
	/// appear oriented in a single direction in the result.
	///
	void setVisitedEdge(bool newIsVisited);


	/** \brief
	 * Each Edge gives rise to a pair of symmetric DirectedEdges,
	 * in opposite directions.
	 *
	 * @return the DirectedEdge for the same Edge but in the
	 *         opposite direction
	 */
	DirectedEdge* getSym();

	bool isForward();

	void setSym(DirectedEdge *de);

	DirectedEdge* getNext();

	void setNext(DirectedEdge *newNext);

	DirectedEdge* getNextMin();

	void setNextMin(DirectedEdge *newNextMin);

	/** \brief
	 * Tells wheter this edge is a Line
	 *
	 * This edge is a line edge if
	 * - at least one of the labels is a line label
	 * - any labels which are not line labels have all Locations = EXTERIOR
	 * 
	 */
	bool isLineEdge();

	/** \brief
	 * Tells wheter this edge is an Area
	 *
	 * This is an interior Area edge if
	 * - its label is an Area label for both Geometries
	 * - and for each Geometry both sides are in the interior.
	 *
	 * @return true if this is an interior Area edge
	 */
	bool isInteriorAreaEdge();

	/** \brief
	 * Set both edge depths. 
	 *
	 * One depth for a given side is provided. 
	 * The other is computed depending on the Location transition and the
	 * depthDelta of the edge.
	 */
	void setEdgeDepths(int position, int newDepth);

	std::string print();

	std::string printEdge();

protected:

	bool isForwardVar;

private:

	bool isInResultVar;

	bool isVisitedVar;

	/// the symmetric edge
	DirectedEdge *sym;

	/// the next edge in the edge ring for the polygon containing this edge
	DirectedEdge *next; 

	/// the next edge in the MinimalEdgeRing that contains this edge
	DirectedEdge *nextMin; 

	/// the EdgeRing that this edge is part of
	EdgeRing *edgeRing; 

	/// the MinimalEdgeRing that this edge is part of
	EdgeRing *minEdgeRing; 

	/** \brief
	 * The depth of each side (position) of this edge.
	 * The 0 element of the array is never used.
	 */
	int depth[3];

	/// Compute the label in the appropriate orientation for this DirEdge
	void computeDirectedLabel();
};

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

#ifdef GEOS_INLINE
# include "geos/geomgraph/DirectedEdge.inl"
#endif

#endif // ifndef GEOS_GEOMGRAPH_DIRECTEDEDGE_H

/**********************************************************************
 * $Log$
 * Revision 1.5  2006/06/14 14:32:20  strk
 * EdgeEnd::getEdge() made non-virtual and inlined.
 *
 * Revision 1.4  2006/05/04 13:38:13  strk
 * doxygen comments cleanup
 *
 * Revision 1.3  2006/03/24 09:52:41  strk
 * USE_INLINE => GEOS_INLINE
 *
 * Revision 1.2  2006/03/15 15:27:23  strk
 * cleanups
 *
 * Revision 1.1  2006/03/09 16:46:49  strk
 * geos::geom namespace definition, first pass at headers split
 *
 **********************************************************************/

