/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2012 Excensus LLC.
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Licence as published
 * by the Free Software Foundation. 
 * See the COPYING file for more information.
 *
 **********************************************************************
 *
 * Last port: triangulate/quadedge/Vertex.java r524
 *
 **********************************************************************/

#ifndef GEOS_TRIANGULATE_QUADEDGE_VERTEX_H
#define GEOS_TRIANGULATE_QUADEDGE_VERTEX_H

#include <math.h>
#include <memory>

#include <geos/geom/Coordinate.h>
#include <geos/algorithm/HCoordinate.h>


//fwd declarations
namespace geos {
namespace triangulate {
namespace quadedge {
	class QuadEdge;
}
}
}

namespace geos {
namespace triangulate { //geos.triangulate
namespace quadedge { //geos.triangulate.quadedge

/**
 * Models a site (node) in a {@link QuadEdgeSubdivision}. 
 * The sites can be points on a line string representing a
 * linear site. 
 * 
 * The vertex can be considered as a vector with a norm, length, inner product, cross
 * product, etc. Additionally, point relations (e.g., is a point to the left of a line, the circle
 * defined by this point and two others, etc.) are also defined in this class.
 *
 * It is common to want to attach user-defined data to 
 * the vertices of a subdivision.  
 * One way to do this is to subclass <tt>Vertex</tt>
 * to carry any desired information (see {@link ConstraintVertex}).
 * 
 * @author JTS: David Skea
 * @author JTS: Martin Davis
 * @author Benjamin Campbell
 * */

class GEOS_DLL Vertex {
public:
	static const int LEFT		= 0;
	static const int RIGHT	   = 1;
	static const int BEYOND	  = 2;
	static const int BEHIND	  = 3;
	static const int BETWEEN	 = 4;
	static const int ORIGIN	  = 5;
	static const int DESTINATION = 6;
private:
	geom::Coordinate	  p;

public:
	Vertex(double _x, double _y);

	Vertex(double _x, double _y, double _z);

	Vertex(const geom::Coordinate &_p);

	Vertex();

	inline double getX() const {
		return p.x;
	}

	inline double getY() const {
		return p.y;
	}

	inline double getZ() const {
		return p.z;
	}

	inline void setZ(double _z) {
		p.z = _z;
	}

	inline const geom::Coordinate& getCoordinate() const {
		return p;
	}

	inline bool equals(const Vertex &_x) const
	{
		if (p.x == _x.getX() && p.y == _x.getY())
			return true;
		return false;
	}

	inline bool equals(const Vertex &_x, double tolerance) const
	{
		if (p.distance(_x.getCoordinate()) < tolerance)
			return true;
		return false;
	}

	virtual int classify(const Vertex &p0, const Vertex &p1);

	/**
	 * Computes the cross product k = u X v.
	 * 
	 * @param v a vertex
	 * @return returns the magnitude of u X v
	 */
	inline double crossProduct(const Vertex &v) const
	{
		return (p.x * v.getY() - p.y * v.getX());
	}

	/**
	 * Computes the inner or dot product
	 * 
	 * @param v, a vertex
	 * @return returns the dot product u.v
	 */
	inline double dot(Vertex v) const
	{
		return (p.x * v.getX() + p.y * v.getY());
	}

	/**
	 * Computes the scalar product c(v)
	 * 
	 * @param v, a vertex
	 * @return returns the scaled vector
	 */
	inline std::auto_ptr<Vertex> times(double c) const {
		return std::auto_ptr<Vertex>(new Vertex(c * p.x, c * p.y));
	}

	/* Vector addition */
	inline std::auto_ptr<Vertex> sum(Vertex v) const {
		return std::auto_ptr<Vertex>(new Vertex(p.x + v.getX(), p.y + v.getY()));
	}

	/* and subtraction */
	inline std::auto_ptr<Vertex> sub(const Vertex &v) const {
		return std::auto_ptr<Vertex>(new Vertex(p.x - v.getX(), p.y - v.getY()));
	}

	/* magnitude of vector */
	inline double magn() const {
		return (sqrt(p.x * p.x + p.y * p.y));
	}

	/* returns k X v (cross product). this is a vector perpendicular to v */
	inline std::auto_ptr<Vertex> cross() const {
		return std::auto_ptr<Vertex>(new Vertex(p.y, -p.x));
	}

  /** ************************************************************* */
  /***********************************************************************************************
   * Geometric primitives /
   **********************************************************************************************/

	/**
	 * Tests if the vertex is inside the circle defined by 
	 * the triangle with vertices a, b, c (oriented counter-clockwise). 
	 * 
	 * @param a a vertex of the triangle
	 * @param b a vertex of the triangle
	 * @param c a vertex of the triangle
	 * @return true if this vertex is in the circumcircle of (a,b,c)
	 */
	virtual bool isInCircle(const Vertex &a, const Vertex &b, const Vertex &c) const;

	/**
	 * Tests whether the triangle formed by this vertex and two
	 * other vertices is in CCW orientation.
	 * 
	 * @param b a vertex
	 * @param c a vertex
	 * @returns true if the triangle is oriented CCW
	 */
	inline bool isCCW(const Vertex &b, const Vertex &c) const 
	{
		// is equal to the signed area of the triangle

		return (b.p.x - p.x) * (c.p.y - p.y) 
			- (b.p.y - p.y) * (c.p.x - p.x) > 0;
	}

	bool rightOf(const QuadEdge &e) const;
	bool leftOf(const QuadEdge &e) const;

private:
	static std::auto_ptr<algorithm::HCoordinate> bisector(const Vertex &a, const Vertex &b);

	inline double distance(const Vertex &v1, const Vertex &v2)
	{
		return sqrt(pow(v2.getX() - v1.getX(), 2.0)
				+ pow(v2.getY() - v1.getY(), 2.0));
	}

	/**
	 * Computes the value of the ratio of the circumradius to shortest edge. If smaller than some
	 * given tolerance B, the associated triangle is considered skinny. For an equal lateral
	 * triangle this value is 0.57735. The ratio is related to the minimum triangle angle theta by:
	 * circumRadius/shortestEdge = 1/(2sin(theta)).
	 * 
	 * @param b second vertex of the triangle
	 * @param c third vertex of the triangle
	 * @return ratio of circumradius to shortest edge.
	 */
	virtual double circumRadiusRatio(const Vertex &b, const Vertex &c);

	/**
	 * returns a new vertex that is mid-way between this vertex and another end point.
	 * 
	 * @param a the other end point.
	 * @return the point mid-way between this and that.
	 */
	virtual std::auto_ptr<Vertex> midPoint(const Vertex &a);

	/**
	 * Computes the centre of the circumcircle of this vertex and two others.
	 * 
	 * @param b
	 * @param c
	 * @return the Coordinate which is the circumcircle of the 3 points.
	 */
	virtual std::auto_ptr<Vertex> circleCenter(const Vertex &b, const Vertex &c) const;

	/**
	 * For this vertex enclosed in a triangle defined by three verticies v0, v1 and v2, interpolate
	 * a z value from the surrounding vertices.
	 */
	virtual double interpolateZValue(const Vertex &v0, const Vertex &v1,
			const Vertex &v2) const;

	/**
	 * Interpolates the Z value of a point enclosed in a 3D triangle.
	 */
	static double interpolateZ(const geom::Coordinate &p, const geom::Coordinate &v0, 
			const geom::Coordinate &v1, const geom::Coordinate &v2);

	/**
	 * Computes the interpolated Z-value for a point p lying on the segment p0-p1
	 * 
	 * @param p
	 * @param p0
	 * @param p1
	 * @return
	 */
	static double interpolateZ(const geom::Coordinate &p, const geom::Coordinate &p0, 
			const geom::Coordinate &p1);
};

inline bool operator<(const Vertex& v1, const Vertex& v2) {
  return v1.getCoordinate() < v2.getCoordinate();
}

} //namespace geos.triangulate.quadedge
} //namespace geos.triangulate
} //namespace geos

#endif //GEOS_TRIANGULATE_QUADEDGE_VERTEX_H