#ifndef ANGLE_H
#define ANGLE_H

#include <cmath>
#include <KLib/Assertions.h>

struct Angle {


public:

	/** get the radians from (x1,y1) to (x2,y2) between 0 (to-the-right) and <2_PI */
	static float getRAD_2PI(const float x1, const float y1, const float x2, const float y2) {
		_assertFalse( (x1==x2)&&(y1==y2), "(x1,y1) must not equal (x2,y2)!!");
		const float tmp = std::atan2(y2-y1, x2-x1);
		return (tmp < 0) ? (tmp + 2*M_PI) : (tmp);
	}

	/** get the degrees from (x1,y1) to (x2,y2) between 0 (to-the-right) and <360 */
	static float getDEG_360(const float x1, const float y1, const float x2, const float y2) {
		return radToDeg(getRAD_2PI(x1,y1,x2,y2));
	}

	/**
	 * gets the angular difference between
	 * - the given radians [0:2PI]
	 * - as a change-in-direction between [0:PI]
	 */
	static float getDiffRAD_2PI_PI(const float r1, const float r2) {
		_assertBetween(r1, 0, 2*M_PI, "r1 out of bounds");
		_assertBetween(r2, 0, 2*M_PI, "r2 out of bounds");
		float tmp = std::abs(r1-r2);
		return (tmp <= M_PI) ? (tmp) : (2*M_PI-tmp);
		//float tmp2 = fmod(tmp, M_PI);
		//return fmod(std::abs(r2 - r1), M_PI);

	}

	/** convert degrees to radians */
	static constexpr float degToRad(const float deg) {
		return deg / 180 * M_PI;
	}

	/** convert radians to degrees */
	static float radToDeg(const float rad) {
		return rad * 180 / M_PI;
	}

};

#endif // ANGLE_H