#include "config.h"
#include "spring.h"

class Joint {
private:
	int		index;
	int		fixed;
	float  dx,dy;
	float	x,y;
	float	t;
	float  dt;
	Vector	force;
	Vector	velocity;
	Vector  acceleration;
	Spring  *springs[JOINT_MAX_SPRINGS];
	int		springwhich[JOINT_MAX_SPRINGS];
	int		springcount;

	class xTooManySprings {};

	static float S_gravity;
	static float S_mass;
	static float S_world_width;
	friend class World;
	
public:
	Joint(float nx, float ny) { 
		x		= nx; 
		y		= ny; 
		t		= 0;
		fixed	= 0;
		index	= 0;
	}
	Joint(float nx, float ny, int nf) {
		x 		= nx;
		y		= ny;
		t		= 0;
		fixed	= nf;
		index   = 0;
	}
	Joint(float nx, float ny, int nf, int i) {
		x 		= nx;
		y		= ny;
		t		= 0;
		fixed	= nf;
		index	= i;
	}
	Joint() { x=0; y=0; t=0; fixed=0; index=0; }
	float X() { return x; }
	float Y() { return y; }
	float DX() { return dx; }
	float DY() { return dy; }
	int Index() { return index; } 
	
	void Fix();
	void Unfix();
	int IsFixed() { return fixed; }

	int Springs() { return springcount; }
	Spring *GetSpring(int i) { return springs[i]; }
	int SpringEnd(int i) { return springwhich[i]; }
	float SpringX(int i,int j) { return springs[i]->X(j); }
	float SpringY(int i,int j) { return springs[i]->Y(j); }

	void Translate() { if (!fixed) this->MoveTo(x+dx,y+dy); }
	void MoveTo(float nx, float ny); 
	void OnTimeSlice(float ndt);
	void ApplyForce(float na, float nf);
	void ApplyForce(Vector F);
	void BounceY();
	void BounceX();
	//bool ConnectedTo(Joint *J);
	Spring *ConnectedTo(Joint *J);

	void ConnectSpring(Spring &s, int i);
	Spring* DisconnectSpring(int s);
	Spring* ConnectJoint(Joint &j);

	static float Gravity() 		   { return S_gravity; }
	static float Gravity(float g)  { return S_gravity = g; }
	static float Mass()			   { return S_mass; }
	static float Mass(float m)	   { return S_mass = m; }
	static float WorldWidth() 	   { return S_world_width; }
	static float WorldWidth(float w) { return S_world_width = w; }

};