#ifndef _PHYSICS_COLLISIONS_
#define _PHYSICS_COLLISIONS_

#include <wgd/vector.h>

#include <vector>

class Body;
class Polygon;
class Circle;

class Collisions
{
	public:
	
	class Contact
	{
		public:
			Body* body[2];
			float penetration;
			float approachSpeed;
			wgd::Vector2D normal;
			wgd::Vector2D position;
			
			wgd::Vector3D offset[2];
			
			float inverseMass[2];
			float angularComponent[2];
			
			bool isEdge[2];
			int featureID[2];
			
			void init (Body* b1, Body* b2);
			void recalculate ();
			void calculateVelocities ();
			void swapBodies ();
	};
	
	static void init ();
	
	static void resolve ();
	
	static void draw ();
	
	static bool check (Body* b1, Body* b2);
	
	static bool checkBounds (Body* b1, Body* b2);
	
	static bool check (Circle* c1, Circle* c2);
	
	private:
	
	static std::vector<Contact> contacts;
	
	static void resolveVelocities (Contact& data);
	static void resolvePenetration (Contact& data, float* moveLinear, float* moveAngular);
	
	static void updateVelocities (std::vector<Contact>::iterator& here);
	static void updatePenetrations (std::vector<Contact>::iterator& here, float* moveLinear, float* moveAngular);
};

#endif