#ifndef _BASIC_GEOMETRY_ANGLE_H_
#define _BASIC_GEOMETRY_ANGLE_H_

#include <math.h>
#include "basis.h"

#define FP32_PI           3.1415926536f
#define FP32_TWO_PI       6.2831853072f
#define FP32_HALF_OF_PI   1.5707963268f
#define FP32_THIRD_OF_PI  1.0471975512f
#define FP32_FOURTH_OF_PI 0.7853981634f
#define FP32_SIXTH_OF_PI  0.5235987756f

#define FP32_DEGREES_IN_RADIAN 57.295779513f
#define FP32_TURNS_IN_RADIAN   0.1591549431f
#define FP32_RADIANS_IN_DEGREE 1.745329252E-2f
#define FP32_TURNS_IN_DEGREE   2.7777777778E-3f

#define FP64_PI           3.14159265358979324
#define FP64_TWO_PI       6.28318530717958648
#define FP64_HALF_OF_PI   1.57079632679489662
#define FP64_THIRD_OF_PI  1.04719755119659775
#define FP64_FOURTH_OF_PI 0.78539816339744831
#define FP64_SIXTH_OF_PI  0.523598775598298873

#define FP64_DEGREES_IN_RADIAN 57.2957795130823209
#define FP64_TURNS_IN_RADIAN   0.159154943091895336
#define FP64_RADIANS_IN_DEGREE 1.74532925199432958E-2
#define FP64_TURNS_IN_DEGREE   2.77777777777777778E-3

typedef enum {
    BG_ANGLE_UNIT_RADIANS = 1,
    BG_ANGLE_UNIT_DEGREES = 2,
    BG_ANGLE_UNIT_TURNS   = 3
} angle_unit_t;

typedef enum {
    /**
     * The measure of an angle with a range of:
     * [0, 360) degrees, [0, 2xPI) radians, [0, 1) turns, [0, 400) gradians
     */
    BG_ANGLE_RANGE_UNSIGNED = 1,

    /**
     * The measure of an angle with a range of:
     * (-180, 180] degrees, (-PI, PI] radians, (-0.5, 0.5] turns, (-200, 200] gradians
     */
    BG_ANGLE_RANGE_SIGNED = 2
} angle_range_t;

// !================= Radians ==================! //

// ========= Convert radians to degrees ========= //

static inline float fp32_radians_to_degrees(const float radians)
{
    return radians * FP32_DEGREES_IN_RADIAN;
}

static inline double fp64_radians_to_degrees(const double radians)
{
    return radians * FP64_DEGREES_IN_RADIAN;
}

// ========== Convert radians to turns ========== //

static inline float fp32_radians_to_turns(const float radians)
{
    return radians * FP32_TURNS_IN_RADIAN;
}

static inline double fp64_radians_to_turns(const double radians)
{
    return radians * FP64_TURNS_IN_RADIAN;
}

// ========= Convert radians to any unit ======== //

static inline float fp32_radians_to_units(const float radians, const angle_unit_t to_unit)
{
    if (to_unit == BG_ANGLE_UNIT_DEGREES) {
        return radians * FP32_DEGREES_IN_RADIAN;
    }

    if (to_unit == BG_ANGLE_UNIT_TURNS) {
        return radians * FP32_TURNS_IN_RADIAN;
    }

    return radians;
}

static inline double fp64_radians_to_units(const double radians, const angle_unit_t to_unit)
{
    if (to_unit == BG_ANGLE_UNIT_DEGREES) {
        return radians * FP64_DEGREES_IN_RADIAN;
    }

    if (to_unit == BG_ANGLE_UNIT_TURNS) {
        return radians * FP64_TURNS_IN_RADIAN;
    }

    return radians;
}

// ============ Normalize radians ============= //

static inline float fp32_radians_normalize(const float radians, const angle_range_t range)
{
    if (range == BG_ANGLE_RANGE_UNSIGNED) {
        if (0.0f <= radians && radians < FP32_TWO_PI) {
            return radians;
        }
    }
    else {
        if (-FP32_PI < radians && radians <= FP32_PI) {
            return radians;
        }
    }

    float turns = radians * FP32_TURNS_IN_RADIAN;

    turns -= floorf(turns);

    if (range == BG_ANGLE_RANGE_SIGNED && turns > 0.5f) {
        turns -= 1.0f;
    }

    return turns * FP32_TWO_PI;
}

static inline double fp64_radians_normalize(const double radians, const angle_range_t range)
{
    if (range == BG_ANGLE_RANGE_UNSIGNED) {
        if (0.0 <= radians && radians < FP64_TWO_PI) {
            return radians;
        }
    }
    else {
        if (-FP64_PI < radians && radians <= FP64_PI) {
            return radians;
        }
    }

    double turns = radians * FP64_TURNS_IN_RADIAN;

    turns -= floor(turns);

    if (range == BG_ANGLE_RANGE_SIGNED && turns > 0.5) {
        turns -= 1.0;
    }

    return turns * FP64_TWO_PI;
}

// !================= Degrees ==================! //

// ========= Convert degrees to radians ========= //

static inline float fp32_degrees_to_radians(const float degrees)
{
    return degrees * FP32_RADIANS_IN_DEGREE;
}

static inline double fp64_degrees_to_radians(const double degrees)
{
    return degrees * FP64_RADIANS_IN_DEGREE;
}

// ========== Convert degrees to turns ========== //

static inline float fp32_degrees_to_turns(const float radians)
{
    return radians * FP32_TURNS_IN_DEGREE;
}

static inline double fp64_degrees_to_turns(const double radians)
{
    return radians * FP64_TURNS_IN_DEGREE;
}

// ========= Convert degreess to any unit ======== //

static inline float fp32_degrees_to_units(const float degrees, const angle_unit_t to_unit)
{
    if (to_unit == BG_ANGLE_UNIT_RADIANS) {
        return degrees * FP32_RADIANS_IN_DEGREE;
    }

    if (to_unit == BG_ANGLE_UNIT_TURNS) {
        return degrees * FP32_TURNS_IN_DEGREE;
    }

    return degrees;
}

static inline double fp64_degrees_to_units(const double degrees, const angle_unit_t to_unit)
{
    if (to_unit == BG_ANGLE_UNIT_RADIANS) {
        return degrees * FP64_RADIANS_IN_DEGREE;
    }

    if (to_unit == BG_ANGLE_UNIT_TURNS) {
        return degrees * FP64_TURNS_IN_DEGREE;
    }

    return degrees;
}

// ============ Normalize degrees ============= //

static inline float fp32_degrees_normalize(const float degrees, const angle_range_t range)
{
    if (range == BG_ANGLE_RANGE_UNSIGNED) {
        if (0.0f <= degrees && degrees < 360.0f) {
            return degrees;
        }
    }
    else {
        if (-180.0f < degrees && degrees <= 180.0f) {
            return degrees;
        }
    }

    float turns = degrees * FP32_TURNS_IN_DEGREE;

    turns -= floorf(turns);

    if (range == BG_ANGLE_RANGE_SIGNED && turns > 0.5f) {
        turns -= 1.0f;
    }

    return turns * 360.0f;
}

static inline double fp64_degrees_normalize(const double degrees, const angle_range_t range)
{
    if (range == BG_ANGLE_RANGE_UNSIGNED) {
        if (0.0 <= degrees && degrees < 360.0) {
            return degrees;
        }
    }
    else {
        if (-180.0 < degrees && degrees <= 180.0) {
            return degrees;
        }
    }

    double turns = degrees * FP64_TURNS_IN_DEGREE;

    turns -= floor(turns);

    if (range == BG_ANGLE_RANGE_SIGNED && turns > 0.5) {
        turns -= 1.0;
    }

    return turns * 360.0;
}

// !================== Turns ===================! //

// ========== Convert turns to radians ========== //

static inline float fp32_turns_to_radians(const float turns)
{
    return turns * FP32_TWO_PI;
}

static inline double fp64_turns_to_radians(const double turns)
{
    return turns * FP64_TWO_PI;
}

// ========== Convert turns to degrees ========== //

static inline float fp32_turns_to_degrees(const float turns)
{
    return turns * 360.0f;
}

static inline double fp64_turns_to_degrees(const double turns)
{
    return turns * 360.0;
}

// ========= Convert turns to any unit ======== //

static inline float fp32_turns_to_units(const float turns, const angle_unit_t to_unit)
{
    if (to_unit == BG_ANGLE_UNIT_RADIANS) {
        return turns * FP32_TWO_PI;
    }

    if (to_unit == BG_ANGLE_UNIT_DEGREES) {
        return turns * 360.0f;
    }

    return turns;
}

static inline double fp64_turns_to_units(const double turns, const angle_unit_t to_unit)
{
    if (to_unit == BG_ANGLE_UNIT_RADIANS) {
        return turns * FP64_TWO_PI;
    }

    if (to_unit == BG_ANGLE_UNIT_DEGREES) {
        return turns * 360.0;
    }

    return turns;
}

// ============= Normalize turns ============== //

static inline float fp32_turns_normalize(const float turns, const angle_range_t range)
{
    if (range == BG_ANGLE_RANGE_UNSIGNED) {
        if (0.0f <= turns && turns < 1.0f) {
            return turns;
        }
    }
    else {
        if (-0.5f < turns && turns <= 0.5f) {
            return turns;
        }
    }

    float rest = turns - floorf(turns);

    if (range == BG_ANGLE_RANGE_SIGNED && rest > 0.5f) {
        return rest - 1.0f;
    }

    return rest;
}

static inline double fp64_turns_normalize(const double turns, const angle_range_t range)
{
    if (range == BG_ANGLE_RANGE_UNSIGNED) {
        if (0.0 <= turns && turns < 1.0) {
            return turns;
        }
    }
    else {
        if (-0.5 < turns && turns <= 0.5) {
            return turns;
        }
    }

    double rest = turns - floor(turns);

    if (range == BG_ANGLE_RANGE_SIGNED && rest > 0.5) {
        return rest - 1.0;
    }

    return rest;
}

// !================== Angle ===================! //

// ========= Convert any unit to radians ======== //

static inline float fp32_angle_to_radians(const float angle, const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return angle * FP32_RADIANS_IN_DEGREE;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return angle * FP32_TWO_PI;
    }

    return angle;
}

static inline double fp64_angle_to_radians(const double angle, const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return angle * FP64_RADIANS_IN_DEGREE;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return angle * FP64_TWO_PI;
    }

    return angle;
}

// ========= Convert any unit to degreess ======== //

static inline float fp32_angle_to_degrees(const float angle, const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_RADIANS) {
        return angle * FP32_DEGREES_IN_RADIAN;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return angle * 360.0f;
    }

    return angle;
}

static inline double fp64_angle_to_degrees(const double angle, const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_RADIANS) {
        return angle * FP64_DEGREES_IN_RADIAN;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return angle * 360.0;
    }

    return angle;
}

// ========= Convert any unit to turns ======== //

static inline float fp32_angle_to_turns(const float angle, const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_RADIANS) {
        return angle * FP32_TURNS_IN_RADIAN;
    }

    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return angle * FP32_TURNS_IN_DEGREE;
    }

    return angle;
}

static inline double fp64_angle_to_turns(const double angle, const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_RADIANS) {
        return angle * FP64_TURNS_IN_RADIAN;
    }

    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return angle * FP64_TURNS_IN_DEGREE;
    }

    return angle;
}

// ============= Get Full Circle ============== //

static inline float fp32_angle_get_full_circle(const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return 360.0f;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return 1.0f;
    }

    return FP32_TWO_PI;
}

static inline double fp64_angle_get_full_circle(const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return 360.0;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return 1.0;
    }

    return FP64_TWO_PI;
}

// ============= Get Half Circle ============== //

static inline float fp32_angle_get_half_circle(const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return 180.0f;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return 0.5f;
    }

    return FP32_PI;
}

static inline double fp64_angle_get_half_circle(const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return 180.0;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return 0.5;
    }

    return FP64_PI;
}

// ============= Get Half Circle ============== //

static inline float fp32_angle_get_quater_circle(const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return 90.0f;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return 0.25f;
    }

    return FP32_HALF_OF_PI;
}

static inline double fp64_angle_get_quater_circle(const angle_unit_t unit)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return 90.0;
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return 0.25;
    }

    return FP64_HALF_OF_PI;
}

// ================ Normalize ================= //

static inline float fp32_angle_normalize(const float angle, const angle_unit_t unit, const angle_range_t range)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return fp32_degrees_normalize(angle, range);
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return fp32_turns_normalize(angle, range);
    }

    return fp32_radians_normalize(angle, range);
}

static inline double fp64_angle_normalize(const double angle, const angle_unit_t unit, const angle_range_t range)
{
    if (unit == BG_ANGLE_UNIT_DEGREES) {
        return fp64_degrees_normalize(angle, range);
    }

    if (unit == BG_ANGLE_UNIT_TURNS) {
        return fp64_turns_normalize(angle, range);
    }

    return fp64_radians_normalize(angle, range);
}

#endif