#ifndef LERP_FUNCTIONS_H
#define LERP_FUNCTIONS_H
#ifdef _WIN32
#pragma once
#endif


template <class T>
inline T LoopingLerp(float flPercent, T flFrom, T flTo)
{
	T s = flTo * flPercent + flFrom * (1.0f - flPercent);
	return s;
}

template <>
inline float LoopingLerp(float flPercent, float flFrom, float flTo)
{
	if (fabs(flTo - flFrom) >= 0.5f)
	{
		if (flFrom < flTo)
			flFrom += 1.0f;
		else
			flTo += 1.0f;
	}

	float s = flTo * flPercent + flFrom * (1.0f - flPercent);

	s = s - (int)(s);
	if (s < 0.0f)
		s = s + 1.0f;

	return s;
}

template <class T>
inline T Lerp_Hermite(const T& , float t, const T& p0, const T& p1, const T& p2)
{
	T d1 = p1 - p0;
	T d2 = p2 - p1;

	T output;
	float tSqr = t * t;
	float tCube = t * tSqr;

	output = p1 * (2 * tCube - 3 * tSqr + 1);
	output += p2 * (-2 * tCube + 3 * tSqr);
	output += d1 * (tCube - 2 * tSqr + t);
	output += d2 * (tCube - tSqr);

	return output;
}


template <class T>
inline T Derivative_Hermite(float t, const T& p0, const T& p1, const T& p2)
{
	T d1 = p1 - p0;
	T d2 = p2 - p1;

	T output;
	float tSqr = t * t;

	output = p1 * (6 * tSqr - 6 * t);
	output += p2 * (-6 * tSqr + 6 * t);
	output += d1 * (3 * tSqr - 4 * t + 1);
	output += d2 * (3 * tSqr - 2 * t);

	return output;
}


inline void Lerp_Clamp(int val)
{
}

inline void Lerp_Clamp(float val)
{
}

inline void Lerp_Clamp(const Vector& val)
{
}

inline void Lerp_Clamp(const QAngle& val)
{
}


template< class T, int minValue, int maxValue, int startValue >
inline void Lerp_Clamp(CRangeCheckedVar<T, minValue, maxValue, startValue>& val)
{
	val.Clamp();
}


template<>
inline QAngle Lerp_Hermite<QAngle>(const QAngle&, float t, const QAngle& p0, const QAngle& p1, const QAngle& p2)
{
	return Lerp(t, p1, p2);
}

template <class T>
inline T LoopingLerp_Hermite(T current, float t, T p0, T p1, T p2)
{
	return Lerp_Hermite(current, t, p0, p1, p2);
}

template <>
inline float LoopingLerp_Hermite(float , float t, float p0, float p1, float p2)
{
	if (fabs(p1 - p0) > 0.5f)
	{
		if (p0 < p1)
			p0 += 1.0f;
		else
			p1 += 1.0f;
	}

	if (fabs(p2 - p1) > 0.5f)
	{
		if (p1 < p2)
		{
			p1 += 1.0f;

			if (abs(p1 - p0) > 0.5)
			{
				if (p0 < p1)
					p0 += 1.0f;
				else
					p1 += 1.0f;
			}
		}
		else
		{
			p2 += 1.0f;
		}
	}

	float s = Lerp_Hermite(  0.0f, t, p0, p1, p2);

	s = s - (int)(s);
	if (s < 0.0f)
	{
		s = s + 1.0f;
	}

	return s;
}

template< int minValue, int maxValue, int startValue >
inline CRangeCheckedVar<float, minValue, maxValue, startValue> LoopingLerp_Hermite(CRangeCheckedVar<float, minValue, maxValue, startValue> current, float t, CRangeCheckedVar<float, minValue, maxValue, startValue> p0, CRangeCheckedVar<float, minValue, maxValue, startValue> p1, CRangeCheckedVar<float, minValue, maxValue, startValue> p2)
{
	return LoopingLerp_Hermite((float)current, t, (float)p0, (float)p1, (float)p2);
}


#endif