#ifndef _Polygon3_h__
#define _Polygon3_h__


//#include <iostream>
//#include <math.h>
//#include "common.h"
#include "Containers.h"
#include "Mesh.h"
#include <iomanip>

class Polygon3;
class Plane3;
class Face;
class Intersectable;
class AxisAlignedBox3;
class Ray;
//typedef Vertex3 Vector3;

/** Class representing a planar convex polygon in 3d.
*/
class Polygon3
{
public:
	Polygon3();
	Polygon3(const VertexContainer &vertices);
	Polygon3(MeshInstance *parent);
	// creates an "infinite" polygon from this plane
	//Polygon3(Plane3 plane);
	/** Copies all the vertices of the face.
	*/
	Polygon3(Face *face, Mesh *parentMesh);
	
	/** Returns supporting plane of this polygon.
	*/
	Plane3 GetSupportingPlane() const;

	/** Splits polygon.
		@param partition the split plane
		@param front returns the front the front polygon
		@param back returns the back polygon
		@param splitPts returns the split points
	*/
	void Polygon3::Split(const Plane3 &partition, 
						 Polygon3 &front, 
						 Polygon3 &back, 
						 VertexContainer &splitPts);

	/** Returns the area of this polygon.
	*/
	float GetArea() const;

	enum {BACK_SIDE, FRONT_SIDE, SPLIT, COINCIDENT};

	/** Classify polygon with respect to the plane.
	    @returns one of BACK_SIDE, FRONT_SIDE, SPLIT, COINCIDENT
	*/
	int ClassifyPlane(const Plane3 &plane) const;

	/** Side of the polygon with respect to the plane.
		@returns 1 if on front side, -1 if on back side, 0 else.
	*/
	int Side(const Plane3 &plane) const;

	/** Scales the polygon about its center
	*/
	void Scale(const float scale);
	
	/** Computes the center of mass of the polygon
	 */
	Vector3 Center() const;
	/** Checks if the polygon is valid, i.e., not degenerated.
		@returns true if polygon is valid.
	*/
	bool Valid() const; 

	/** Returns the surface normal.
	*/
	Vector3 GetNormal() const;

	/** Includes polygons to axis aligned box.
	*/
	static void IncludeInBox(const PolygonContainer &polys, AxisAlignedBox3 &box);

	/** Casts ray to polygon.
	*/
	int CastRay(const Ray &ray, float &t, const float nearestT);

	/// vertices are connected in counterclockwise order.
	VertexContainer mVertices;

	/// we can also store materials with polygons
	Material *mMaterial;
	
	/// pointer to the mesh instance this polygon is derived from
	MeshInstance *mParent;
};

// Overload << operator for C++-style output
inline ostream&
operator<< (ostream &s, const Polygon3 &A)
{
	VertexContainer::const_iterator it;

	//s << setprecision(6) << "Polygon:\n";
	for (it = A.mVertices.begin(); it != A.mVertices.end(); ++it)
		s << *it << endl;
	
	return s;
}


#endif