#include "config.h"
#include "vector.h"

class Spring {
private:
	float mass;
	float x[2];
	float y[2];
	int	  joint[2];
	float a;
	int freejoints;
	float length;
	float muscle_offset;
	float muscle_frequency;
	float muscle_amplitude;
	float muscle;
	static int S_muscle_flow;
	static float S_t;
	static float S_k;

public:
	Spring(float nx1, float ny1, float nx2, float ny2, int fj);
	Spring(float nx1, float ny1, int fj);
	Spring();

	void AddJoint(float nx, float ny, int fj);
	void AddMuscle(float f, float a, float dt);
	
	float X(int i) 						{ return x[i]; }
	float Y(int i) 						{ return y[i]; }
	float A() 							{ return a; }
	float Length() 						{ return length; }
	float Muscle() 						{ return muscle; }
	float MuscleAmplitude()				{ return muscle_amplitude; }
	float MuscleOffset()				{ return muscle_offset; }
	float MuscleFrequency()				{ return muscle_frequency; }
	float MuscleAmplitude(float a)		{ return muscle_amplitude=a; }
	float MuscleOffset(float o)			{ return muscle_offset=o; }
	float MuscleFrequency(float f)		{ return muscle_frequency=f; }
	void Set(int i, float nx, float ny) { x[i]=nx; y[i]=ny; }
	int ConnectedJoint(int i, int j)	{ return joint[i]=j; }
	int ConnectedJoint(int i)			{ return joint[i]; }
	void Fix() 							{ freejoints--; }
	void Unfix() 						{ freejoints++; }
	
	static void ReverseMuscles() 	{ S_muscle_flow = -S_muscle_flow; }
	static int MuscleFlow(int nf) 	{ return S_muscle_flow = nf; }
	static int MuscleFlow() 		{ return S_muscle_flow; }	
	static float T() 				{ return S_t; } 
	static float T(float dt) 		{ return S_t+=dt * S_muscle_flow; }
	static float K()				{ return S_k; }
	static float K(float nk)		{ return S_k = nk; }
	
	Vector ResultantForce(int which, float dt);

	class xNoMatch {};
};