/*************************************************************************/
/*  Quaternion.h                                                             */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           PANDEMONIUM ENGINE                                */
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/*************************************************************************/
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/* Copyright (c) 2014-2022 Pandemonium Engine contributors (cf. AUTHORS.md).   */
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/*************************************************************************/

#ifndef QUATERNION_H
#define QUATERNION_H

#include <cmath>

#include "vector3.h"

class Quaternion {
public:
	static const Quaternion IDENTITY;

	real_t x, y, z, w;

	real_t length_squared() const;
	real_t length() const;

	void normalize();

	Quaternion normalized() const;

	bool is_normalized() const;

	Quaternion inverse() const;

	void set_euler_xyz(const Vector3 &p_euler);
	Vector3 get_euler_xyz() const;
	void set_euler_yxz(const Vector3 &p_euler);
	Vector3 get_euler_yxz() const;

	inline void set_euler(const Vector3 &p_euler) { set_euler_yxz(p_euler); }
	inline Vector3 get_euler() const { return get_euler_yxz(); }

	real_t dot(const Quaternion &q) const;

	Quaternion slerp(const Quaternion &q, const real_t &t) const;

	Quaternion slerpni(const Quaternion &q, const real_t &t) const;

	Quaternion cubic_slerp(const Quaternion &q, const Quaternion &prep, const Quaternion &postq, const real_t &t) const;

	void get_axis_and_angle(Vector3 &r_axis, real_t &r_angle) const;

	void set_axis_angle(const Vector3 &axis, const float angle);

	void operator*=(const Quaternion &q);
	Quaternion operator*(const Quaternion &q) const;

	Quaternion operator*(const Vector3 &v) const;

	Vector3 xform(const Vector3 &v) const;

	void operator+=(const Quaternion &q);
	void operator-=(const Quaternion &q);
	void operator*=(const real_t &s);
	void operator/=(const real_t &s);
	Quaternion operator+(const Quaternion &q2) const;
	Quaternion operator-(const Quaternion &q2) const;
	Quaternion operator-() const;
	Quaternion operator*(const real_t &s) const;
	Quaternion operator/(const real_t &s) const;

	bool operator==(const Quaternion &p_quaternion) const;
	bool operator!=(const Quaternion &p_quaternion) const;

	operator String() const;

	inline void set(real_t p_x, real_t p_y, real_t p_z, real_t p_w) {
		x = p_x;
		y = p_y;
		z = p_z;
		w = p_w;
	}
	inline Quaternion(real_t p_x, real_t p_y, real_t p_z, real_t p_w) {
		x = p_x;
		y = p_y;
		z = p_z;
		w = p_w;
	}
	Quaternion(const Vector3 &axis, const real_t &angle);

	Quaternion(const Vector3 &v0, const Vector3 &v1);

	inline Quaternion() {
		x = y = z = 0;
		w = 1;
	}
};

#endif // QUAT_H