/**********************************************************************
 * $Id: IsValidOp.h 1820 2006-09-06 16:54:23Z mloskot $
 *
 * 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.
 *
 **********************************************************************/

#ifndef GEOS_OP_ISVALIDOP_H
#define GEOS_OP_ISVALIDOP_H

#include <geos/operation/valid/TopologyValidationError.h> // for inlined destructor

// Forward declarations
namespace geos {
	namespace util {
		class TopologyValidationError;
	}
	namespace geom {
		class CoordinateSequence;
		class GeometryFactory;
		class Geometry;
		class Point;
		class LinearRing;
		class LineString;
		class Polygon;
		class GeometryCollection;
		class MultiPolygon;
		class MultiLineString;
	}
	namespace geomgraph {
		class DirectedEdge;
		class EdgeIntersectionList;
		class PlanarGraph;
		class GeometryGraph;
	}
}

namespace geos {
namespace operation { // geos::operation
namespace valid { // geos::operation::valid

/** \brief
 * Implements the algorithsm required to compute the <code>isValid()</code> method
 * for {@link Geometry}s.
 *
 */
class IsValidOp {
friend class Unload;
private:
	const geom::Geometry *parentGeometry;  // the base Geometry to be validated
	bool isChecked;
	TopologyValidationError* validErr; // CHECKME: should this really be a pointer ?
	void checkValid(const geom::Geometry *g);
	void checkValid(const geom::Point *g);
	void checkValid(const geom::LinearRing *g);
	void checkValid(const geom::LineString *g);
	void checkValid(const geom::Polygon *g);
	void checkValid(const geom::MultiPolygon *g);
	void checkValid(const geom::GeometryCollection *gc);
	void checkConsistentArea(geomgraph::GeometryGraph *graph);


	/**
	 * Check that there is no ring which self-intersects
	 * (except of course at its endpoints).
	 * This is required by OGC topology rules (but not by other models
	 * such as ESRI SDE, which allow inverted shells and exverted holes).
	 *
	 * @param graph the topology graph of the geometry
	 */
	void checkNoSelfIntersectingRings(geomgraph::GeometryGraph *graph);

	/**
	 * check that a ring does not self-intersect, except at its endpoints.
	 * Algorithm is to count the number of times each node along edge
	 * occurs.
	 * If any occur more than once, that must be a self-intersection.
	 */
	void checkNoSelfIntersectingRing(
			geomgraph::EdgeIntersectionList &eiList);

	void checkTooFewPoints(geomgraph::GeometryGraph *graph);

	/**
	 * Test that each hole is inside the polygon shell.
	 * This routine assumes that the holes have previously been tested
	 * to ensure that all vertices lie on the shell or inside it.
	 * A simple test of a single point in the hole can be used,
	 * provide the point is chosen such that it does not lie on the
	 * boundary of the shell.
	 *
	 * @param p the polygon to be tested for hole inclusion
	 * @param graph a geomgraph::GeometryGraph incorporating the polygon
	 */
	void checkHolesInShell(const geom::Polygon *p,
			geomgraph::GeometryGraph *graph);

	/**
	 * Tests that no hole is nested inside another hole.
	 * This routine assumes that the holes are disjoint.
	 * To ensure this, holes have previously been tested
	 * to ensure that:
	 * 
	 *  - they do not partially overlap
	 *    (checked by <code>checkRelateConsistency</code>)
	 *  - they are not identical
	 *    (checked by <code>checkRelateConsistency</code>)
	 * 
	 */
	void checkHolesNotNested(const geom::Polygon *p,
			geomgraph::GeometryGraph *graph);

	/**
	 * Tests that no element polygon is wholly in the interior of another
	 * element polygon.
	 * 
	 * Preconditions:
	 * 
	 * - shells do not partially overlap
	 * - shells do not touch along an edge
	 * - no duplicate rings exist
	 *
	 * This routine relies on the fact that while polygon shells
	 * may touch at one or more vertices, they cannot touch at
	 * ALL vertices.
	 */
	void checkShellsNotNested(const geom::MultiPolygon *mp,
			geomgraph::GeometryGraph *graph);

	/**
	 * Check if a shell is incorrectly nested within a polygon. 
	 * This is the case if the shell is inside the polygon shell,
	 * but not inside a polygon hole.
	 * (If the shell is inside a polygon hole, the nesting is valid.)
	 * 
	 * The algorithm used relies on the fact that the rings must be
	 * properly contained.
	 * E.g. they cannot partially overlap (this has been previously
	 * checked by <code>checkRelateConsistency</code>
	 */
	void checkShellNotNested(const geom::LinearRing *shell,
			const geom::Polygon *p,
			geomgraph::GeometryGraph *graph);

	/**
	 * This routine checks to see if a shell is properly contained
	 * in a hole.
	 * It assumes that the edges of the shell and hole do not
	 * properly intersect.
	 *
	 * @return <code>null</code> if the shell is properly contained, or
	 *   a Coordinate which is not inside the hole if it is not
	 *
	 */
	const geom::Coordinate *checkShellInsideHole(
			const geom::LinearRing *shell,
			const geom::LinearRing *hole,
			geomgraph::GeometryGraph *graph);

	void checkConnectedInteriors(geomgraph::GeometryGraph &graph);

	void checkInvalidCoordinates(const geom::CoordinateSequence *cs);

	void checkInvalidCoordinates(const geom::Polygon *poly);

	void checkClosedRings(const geom::Polygon *poly);

	void checkClosedRing(const geom::LinearRing *ring);

	bool isSelfTouchingRingFormingHoleValid;

public:
	/**
	 * Find a point from the list of testCoords
	 * that is NOT a node in the edge for the list of searchCoords
	 *
	 * @return the point found, or NULL if none found
	 */
	static const geom::Coordinate *findPtNotNode(
			const geom::CoordinateSequence *testCoords,
			const geom::LinearRing *searchRing, geomgraph::GeometryGraph *graph);

	/**
	 * Checks whether a coordinate is valid for processing.
	 * Coordinates are valid iff their x and y coordinates are in the
	 * range of the floating point representation.
	 *
	 * @param coord the coordinate to validate
	 * @return <code>true</code> if the coordinate is valid
	 */
	static bool isValid(const geom::Coordinate &coord);

	IsValidOp(const geom::Geometry *geom)
		:
		parentGeometry(geom),
		isChecked(false),
		validErr(NULL),
		isSelfTouchingRingFormingHoleValid(false)
	{}

	/// TODO: validErr can't be a pointer!
	virtual ~IsValidOp() {
		delete validErr;
	}

	bool isValid();

	TopologyValidationError* getValidationError();

	/** \brief
	 * Sets whether polygons using <b>Self-Touching Rings</b> to form
	 * holes are reported as valid.
	 *
	 * If this flag is set, the following Self-Touching conditions
	 * are treated as being valid:
	 * <ul>
	 * <li>the shell ring self-touches to create a hole touching the shell
	 * <li>a hole ring self-touches to create two holes touching at a point
	 * </ul>
	 * <p>
	 * The default (following the OGC SFS standard)
	 * is that this condition is <b>not</b> valid (<code>false</code>).
	 * <p>
	 * This does not affect whether Self-Touching Rings
	 * disconnecting the polygon interior are considered valid
	 * (these are considered to be <b>invalid</b> under the SFS,
	 * and many other spatial models as well).
	 * This includes "bow-tie" shells,
	 * which self-touch at a single point causing the interior to
	 * be disconnected,
	 * and "C-shaped" holes which self-touch at a single point causing
	 * an island to be formed.
	 *
	 * @param isValid states whether geometry with this condition is valid
	 */
	void setSelfTouchingRingFormingHoleValid(bool isValid)
	{
		isSelfTouchingRingFormingHoleValid = isValid;
	}

};

} // namespace geos.operation.valid
} // namespace geos.operation
} // namespace geos

#endif // GEOS_OP_ISVALIDOP_H

/**********************************************************************
 * $Log$
 * Revision 1.2  2006/03/29 13:53:59  strk
 * EdgeRing equipped with Invariant testing function and lots of exceptional assertions. Removed useless heap allocations, and pointers usages.
 *
 * Revision 1.1  2006/03/20 16:57:44  strk
 * spatialindex.h and opValid.h headers split
 *
 **********************************************************************/

