#ifndef _BGC_VECTOR2_H_
#define _BGC_VECTOR2_H_

#include "utilities.h"
#include "angle.h"

#include <math.h>

typedef struct
{
    float x1, x2;
} BgcVector2FP32;

typedef struct
{
    double x1, x2;
} BgcVector2FP64;

// =================== Reset ==================== //

inline void bgc_vector2_reset_fp32(BgcVector2FP32* vector)
{
    vector->x1 = 0.0f;
    vector->x2 = 0.0f;
}

inline void bgc_vector2_reset_fp64(BgcVector2FP64* vector)
{
    vector->x1 = 0.0;
    vector->x2 = 0.0;
}

// ==================== Set ===================== //

inline void bgc_vector2_set_values_fp32(const float x1, const float x2, BgcVector2FP32* destination)
{
    destination->x1 = x1;
    destination->x2 = x2;
}

inline void bgc_vector2_set_values_fp64(const double x1, const double x2, BgcVector2FP64* destination)
{
    destination->x1 = x1;
    destination->x2 = x2;
}

// ================== Modulus =================== //

inline float bgc_vector2_get_square_modulus_fp32(const BgcVector2FP32* vector)
{
    return vector->x1 * vector->x1 + vector->x2 * vector->x2;
}

inline double bgc_vector2_get_square_modulus_fp64(const BgcVector2FP64* vector)
{
    return vector->x1 * vector->x1 + vector->x2 * vector->x2;
}

inline float bgc_vector2_get_modulus_fp32(const BgcVector2FP32* vector)
{
    return sqrtf(bgc_vector2_get_square_modulus_fp32(vector));
}

inline double bgc_vector2_get_modulus_fp64(const BgcVector2FP64* vector)
{
    return sqrt(bgc_vector2_get_square_modulus_fp64(vector));
}

// ================= Comparison ================= //

inline int bgc_vector2_is_zero_fp32(const BgcVector2FP32* vector)
{
    return bgc_vector2_get_square_modulus_fp32(vector) <= BGC_SQUARE_EPSYLON_FP32;
}

inline int bgc_vector2_is_zero_fp64(const BgcVector2FP64* vector)
{
    return bgc_vector2_get_square_modulus_fp64(vector) <= BGC_SQUARE_EPSYLON_FP64;
}

inline int bgc_vector2_is_unit_fp32(const BgcVector2FP32* vector)
{
    return bgc_is_sqare_unit_fp32(bgc_vector2_get_square_modulus_fp32(vector));
}

inline int bgc_vector2_is_unit_fp64(const BgcVector2FP64* vector)
{
    return bgc_is_sqare_unit_fp64(bgc_vector2_get_square_modulus_fp64(vector));
}

// ==================== Copy ==================== //

inline void bgc_vector2_copy_fp32(const BgcVector2FP32* source, BgcVector2FP32* destination)
{
    destination->x1 = source->x1;
    destination->x2 = source->x2;
}

inline void bgc_vector2_copy_fp64(const BgcVector2FP64* source, BgcVector2FP64* destination)
{
    destination->x1 = source->x1;
    destination->x2 = source->x2;
}

// ==================== Swap ==================== //

inline void bgc_vector2_swap_fp32(BgcVector2FP32* vector1, BgcVector2FP32* vector2)
{
    const float x1 = vector2->x1;
    const float x2 = vector2->x2;

    vector2->x1 = vector1->x1;
    vector2->x2 = vector1->x2;

    vector1->x1 = x1;
    vector1->x2 = x2;
}

inline void bgc_vector2_swap_fp64(BgcVector2FP64* vector1, BgcVector2FP64* vector2)
{
    const double x1 = vector2->x1;
    const double x2 = vector2->x2;

    vector2->x1 = vector1->x1;
    vector2->x2 = vector1->x2;

    vector1->x1 = x1;
    vector1->x2 = x2;
}

// ================== Convert =================== //

inline void bgc_vector2_convert_fp64_to_fp32(const BgcVector2FP64* source, BgcVector2FP32* destination)
{
    destination->x1 = (float)source->x1;
    destination->x2 = (float)source->x2;
}

inline void bgc_vector2_convert_fp32_to_fp64(const BgcVector2FP32* source, BgcVector2FP64* destination)
{
    destination->x1 = source->x1;
    destination->x2 = source->x2;
}

// ==================== Add ===================== //

inline void bgc_vector2_add_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2, BgcVector2FP32* sum)
{
    sum->x1 = vector1->x1 + vector2->x1;
    sum->x2 = vector1->x2 + vector2->x2;
}

inline void bgc_vector2_add_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2, BgcVector2FP64* sum)
{
    sum->x1 = vector1->x1 + vector2->x1;
    sum->x2 = vector1->x2 + vector2->x2;
}

// ================= Add scaled ================= //

inline void bgc_vector2_add_scaled_fp32(const BgcVector2FP32* basic_vector, const BgcVector2FP32* scalable_vector, const float scale, BgcVector2FP32* sum)
{
    sum->x1 = basic_vector->x1 + scalable_vector->x1 * scale;
    sum->x2 = basic_vector->x2 + scalable_vector->x2 * scale;
}

inline void bgc_vector2_add_scaled_fp64(const BgcVector2FP64* basic_vector, const BgcVector2FP64* scalable_vector, const double scale, BgcVector2FP64* sum)
{
    sum->x1 = basic_vector->x1 + scalable_vector->x1 * scale;
    sum->x2 = basic_vector->x2 + scalable_vector->x2 * scale;
}

// ================== Subtract ================== //

inline void bgc_vector2_subtract_fp32(const BgcVector2FP32* minuend, const BgcVector2FP32* subtrahend, BgcVector2FP32* difference)
{
    difference->x1 = minuend->x1 - subtrahend->x1;
    difference->x2 = minuend->x2 - subtrahend->x2;
}

inline void bgc_vector2_subtract_fp64(const BgcVector2FP64* minuend, const BgcVector2FP64* subtrahend, BgcVector2FP64* difference)
{
    difference->x1 = minuend->x1 - subtrahend->x1;
    difference->x2 = minuend->x2 - subtrahend->x2;
}

// ================== Multiply ================== //

inline void bgc_vector2_multiply_fp32(const BgcVector2FP32* multiplicand, const float multiplier, BgcVector2FP32* product)
{
    product->x1 = multiplicand->x1 * multiplier;
    product->x2 = multiplicand->x2 * multiplier;
}

inline void bgc_vector2_multiply_fp64(const BgcVector2FP64* multiplicand, const double multiplier, BgcVector2FP64* product)
{
    product->x1 = multiplicand->x1 * multiplier;
    product->x2 = multiplicand->x2 * multiplier;
}

// =================== Divide =================== //

inline void bgc_vector2_divide_fp32(const BgcVector2FP32* dividend, const float divisor, BgcVector2FP32* quotient)
{
    bgc_vector2_multiply_fp32(dividend, 1.0f / divisor, quotient);
}

inline void bgc_vector2_divide_fp64(const BgcVector2FP64* dividend, const double divisor, BgcVector2FP64* quotient)
{
    bgc_vector2_multiply_fp64(dividend, 1.0 / divisor, quotient);
}

// ================ Mean of Two ================= //

inline void bgc_vector2_get_mean_of_two_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2, BgcVector2FP32* mean)
{
    mean->x1 = (vector1->x1 + vector2->x1) * 0.5f;
    mean->x2 = (vector1->x2 + vector2->x2) * 0.5f;
}

inline void bgc_vector2_get_mean_of_two_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2, BgcVector2FP64* mean)
{
    mean->x1 = (vector1->x1 + vector2->x1) * 0.5;
    mean->x2 = (vector1->x2 + vector2->x2) * 0.5;
}

// =============== Mean of Three ================ //

inline void bgc_vector2_get_mean_of_three_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2, const BgcVector2FP32* vector3, BgcVector2FP32* mean)
{
    mean->x1 = (vector1->x1 + vector2->x1 + vector3->x1) * BGC_ONE_THIRD_FP32;
    mean->x2 = (vector1->x2 + vector2->x2 + vector3->x2) * BGC_ONE_THIRD_FP32;
}

inline void bgc_vector2_get_mean_of_three_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2, const BgcVector2FP64* vector3, BgcVector2FP64* mean)
{
    mean->x1 = (vector1->x1 + vector2->x1 + vector3->x1) * BGC_ONE_THIRD_FP64;
    mean->x2 = (vector1->x2 + vector2->x2 + vector3->x2) * BGC_ONE_THIRD_FP64;
}

// =================== Linear =================== //

inline void bgc_vector2_interpolate_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2, const float phase, BgcVector2FP32* interpolation)
{
    const float counterphase = 1.0f - phase;

    interpolation->x1 = vector1->x1 * counterphase + vector2->x1 * phase;
    interpolation->x2 = vector1->x2 * counterphase + vector2->x2 * phase;
}

inline void bgc_vector2_interpolate_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2, const double phase, BgcVector2FP64* interpolation)
{
    const double counterphase = 1.0 - phase;

    interpolation->x1 = vector1->x1 * counterphase + vector2->x1 * phase;
    interpolation->x2 = vector1->x2 * counterphase + vector2->x2 * phase;
}

// ================== Negative ================== //

inline void bgc_vector2_make_opposite_fp32(BgcVector2FP32* vector)
{
    vector->x1 = -vector->x1;
    vector->x2 = -vector->x2;
}

inline void bgc_vector2_make_opposite_fp64(BgcVector2FP64* vector)
{
    vector->x1 = -vector->x1;
    vector->x2 = -vector->x2;
}

inline void bgc_vector2_get_opposite_fp32(const BgcVector2FP32* vector, BgcVector2FP32* opposite)
{
    opposite->x1 = -vector->x1;
    opposite->x2 = -vector->x2;
}

inline void bgc_vector2_get_opposite_fp64(const BgcVector2FP64* vector, BgcVector2FP64* opposite)
{
    opposite->x1 = -vector->x1;
    opposite->x2 = -vector->x2;
}

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

inline int bgc_vector2_normalize_fp32(BgcVector2FP32* vector)
{
    const float square_modulus = bgc_vector2_get_square_modulus_fp32(vector);

    if (bgc_is_sqare_unit_fp32(square_modulus)) {
        return 1;
    }

    if (square_modulus <= BGC_SQUARE_EPSYLON_FP32 || square_modulus != square_modulus) {
        return 0;
    }

    const float multiplier = sqrtf(1.0f / square_modulus);

    vector->x1 *= multiplier;
    vector->x2 *= multiplier;

    return 1;
}

inline int bgc_vector2_normalize_fp64(BgcVector2FP64* vector)
{
    const double square_modulus = bgc_vector2_get_square_modulus_fp64(vector);

    if (bgc_is_sqare_unit_fp64(square_modulus)) {
        return 1;
    }

    if (square_modulus <= BGC_SQUARE_EPSYLON_FP64 || square_modulus != square_modulus) {
        return 0;
    }

    const double multiplier = sqrt(1.0 / square_modulus);

    vector->x1 *= multiplier;
    vector->x2 *= multiplier;

    return 1;
}

inline int bgc_vector2_get_normalized_fp32(const BgcVector2FP32* vector, BgcVector2FP32* normalized)
{
    const float square_modulus = bgc_vector2_get_square_modulus_fp32(vector);

    if (bgc_is_sqare_unit_fp32(square_modulus)) {
        bgc_vector2_copy_fp32(vector, normalized);
        return 1;
    }

    if (square_modulus <= BGC_SQUARE_EPSYLON_FP32 || square_modulus != square_modulus) {
        bgc_vector2_reset_fp32(normalized);
        return 0;
    }

    bgc_vector2_multiply_fp32(vector, sqrtf(1.0f / square_modulus), normalized);
    return 1;
}

inline int bgc_vector2_get_normalized_fp64(const BgcVector2FP64* vector, BgcVector2FP64* normalized)
{
    const double square_modulus = bgc_vector2_get_square_modulus_fp64(vector);

    if (bgc_is_sqare_unit_fp64(square_modulus)) {
        bgc_vector2_copy_fp64(vector, normalized);
        return 1;
    }

    if (square_modulus <= BGC_SQUARE_EPSYLON_FP64 || square_modulus != square_modulus) {
        bgc_vector2_reset_fp64(normalized);
        return 0;
    }

    bgc_vector2_multiply_fp64(vector, sqrt(1.0 / square_modulus), normalized);
    return 1;
}

// ============= Get Scalar Product ============= //

inline float bgc_vector2_get_scalar_product_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2)
{
    return vector1->x1 * vector2->x1 + vector1->x2 * vector2->x2;
}

inline double bgc_vector2_get_scalar_product_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2)
{
    return vector1->x1 * vector2->x1 + vector1->x2 * vector2->x2;
}

// ============= Get Cross Product ============== //

inline float bgc_vector2_get_cross_product_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2)
{
    return vector1->x1 * vector2->x2 - vector1->x2 * vector2->x1;
}

inline double bgc_vector2_get_cross_product_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2)
{
    return vector1->x1 * vector2->x2 - vector1->x2 * vector2->x1;
}

// ================= Get Angle ================== //

float bgc_vector2_get_angle_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2, const BgcAngleUnitEnum unit);

double bgc_vector2_get_angle_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2, const BgcAngleUnitEnum unit);

// ============= Get Square Distance ============ //

inline float bgc_vector2_get_square_distance_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2)
{
    const float dx1 = vector1->x1 - vector2->x1;
    const float dx2 = vector1->x2 - vector2->x2;

    return dx1 * dx1 + dx2 * dx2;
}

inline double bgc_vector2_get_square_distance_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2)
{
    const double dx1 = vector1->x1 - vector2->x1;
    const double dx2 = vector1->x2 - vector2->x2;

    return dx1 * dx1 + dx2 * dx2;
}

// ================== Distance ================== //

inline float bgc_vector2_get_distance_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2)
{
    return sqrtf(bgc_vector2_get_square_distance_fp32(vector1, vector2));
}

inline double bgc_vector2_get_distance_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2)
{
    return sqrt(bgc_vector2_get_square_distance_fp64(vector1, vector2));
}

// ============== Are Close Enough ============== //

inline int bgc_vector2_are_close_enough_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2, const float distance_limit)
{
    return bgc_vector2_get_square_distance_fp32(vector1, vector2) <= distance_limit * distance_limit;
}

inline int bgc_vector2_are_close_enough_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2, const double distance_limit)
{
    return bgc_vector2_get_square_distance_fp64(vector1, vector2) <= distance_limit * distance_limit;
}

// ================== Are Close ================= //

inline int bgc_vector2_are_close_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2)
{
    const float square_modulus1 = bgc_vector2_get_square_modulus_fp32(vector1);
    const float square_modulus2 = bgc_vector2_get_square_modulus_fp32(vector2);
    const float square_distance = bgc_vector2_get_square_distance_fp32(vector1, vector2);

    if (square_modulus1 <= BGC_EPSYLON_EFFECTIVENESS_LIMIT_FP32 || square_modulus2 <= BGC_EPSYLON_EFFECTIVENESS_LIMIT_FP32) {
        return square_distance <= BGC_SQUARE_EPSYLON_FP32;
    }

    return square_distance <= BGC_SQUARE_EPSYLON_FP32 * square_modulus1 && square_distance <= BGC_SQUARE_EPSYLON_FP32 * square_modulus2;
}

inline int bgc_vector2_are_close_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2)
{
    const double square_modulus1 = bgc_vector2_get_square_modulus_fp64(vector1);
    const double square_modulus2 = bgc_vector2_get_square_modulus_fp64(vector2);
    const double square_distance = bgc_vector2_get_square_distance_fp64(vector1, vector2);

    if (square_modulus1 <= BGC_EPSYLON_EFFECTIVENESS_LIMIT_FP64 || square_modulus2 <= BGC_EPSYLON_EFFECTIVENESS_LIMIT_FP64) {
        return square_distance <= BGC_SQUARE_EPSYLON_FP64;
    }

    return square_distance <= BGC_SQUARE_EPSYLON_FP64 * square_modulus1 && square_distance <= BGC_SQUARE_EPSYLON_FP64 * square_modulus2;
}


// ================== Parallel ================== //

inline int bgc_vector2_are_parallel_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2)
{
    const float square_modulus1 = bgc_vector2_get_square_modulus_fp32(vector1);

    if (square_modulus1 <= BGC_SQUARE_EPSYLON_FP32) {
        return 1;
    }

    const float square_modulus2 = bgc_vector2_get_square_modulus_fp32(vector2);

    if (square_modulus2 <= BGC_SQUARE_EPSYLON_FP32) {
        return 1;
    }

    const float cross_product = bgc_vector2_get_cross_product_fp32(vector1, vector2);

    return cross_product * cross_product <= BGC_SQUARE_EPSYLON_FP32 * square_modulus1 * square_modulus2;
}

inline int bgc_vector2_are_parallel_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2)
{
    const double square_modulus1 = bgc_vector2_get_square_modulus_fp64(vector1);

    if (square_modulus1 <= BGC_SQUARE_EPSYLON_FP64) {
        return 1;
    }

    const double square_modulus2 = bgc_vector2_get_square_modulus_fp64(vector2);

    if (square_modulus2 <= BGC_SQUARE_EPSYLON_FP64) {
        return 1;
    }

    const double cross_product = bgc_vector2_get_cross_product_fp64(vector1, vector2);

    return cross_product * cross_product <= BGC_SQUARE_EPSYLON_FP64 * square_modulus1 * square_modulus2;
}

// ================= Orthogonal ================= //

inline int bgc_vector2_are_orthogonal_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2)
{
    const float square_modulus1 = bgc_vector2_get_square_modulus_fp32(vector1);

    if (square_modulus1 <= BGC_SQUARE_EPSYLON_FP32) {
        return 1;
    }

    const float square_modulus2 = bgc_vector2_get_square_modulus_fp32(vector2);

    if (square_modulus2 <= BGC_SQUARE_EPSYLON_FP32) {
        return 1;
    }

    const float scalar_product = bgc_vector2_get_scalar_product_fp32(vector1, vector2);

    return scalar_product * scalar_product <= BGC_SQUARE_EPSYLON_FP32 * square_modulus1 * square_modulus2;
}

inline int bgc_vector2_are_orthogonal_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2)
{
    const double square_modulus1 = bgc_vector2_get_square_modulus_fp64(vector1);

    if (square_modulus1 <= BGC_SQUARE_EPSYLON_FP64) {
        return 1;
    }

    const double square_modulus2 = bgc_vector2_get_square_modulus_fp64(vector2);

    if (square_modulus2 <= BGC_SQUARE_EPSYLON_FP64) {
        return 1;
    }

    const double scalar_product = bgc_vector2_get_scalar_product_fp64(vector1, vector2);

    return scalar_product * scalar_product <= BGC_SQUARE_EPSYLON_FP64 * square_modulus1 * square_modulus2;
}


// ================== Attitude ================== //

inline int bgc_vector2_get_attitude_fp32(const BgcVector2FP32* vector1, const BgcVector2FP32* vector2)
{
    const float square_modulus1 = bgc_vector2_get_square_modulus_fp32(vector1);
    const float square_modulus2 = bgc_vector2_get_square_modulus_fp32(vector2);

    if (square_modulus1 <= BGC_SQUARE_EPSYLON_FP32 || square_modulus2 <= BGC_SQUARE_EPSYLON_FP32) {
        return BGC_ATTITUDE_ZERO;
    }

    const float square_limit = BGC_SQUARE_EPSYLON_FP32 * square_modulus1 * square_modulus2;

    const float scalar_product = bgc_vector2_get_scalar_product_fp32(vector1, vector2);

    if (scalar_product * scalar_product <= square_limit) {
        return BGC_ATTITUDE_ORTHOGONAL;
    }

    const float cross_product = bgc_vector2_get_cross_product_fp32(vector1, vector2);

    if (cross_product * cross_product > square_limit) {
        return BGC_ATTITUDE_ANY;
    }

    return scalar_product > 0.0f ? BGC_ATTITUDE_CO_DIRECTIONAL : BGC_ATTITUDE_COUNTER_DIRECTIONAL;
}

inline int bgc_vector2_get_attitude_fp64(const BgcVector2FP64* vector1, const BgcVector2FP64* vector2)
{
    const double square_modulus1 = bgc_vector2_get_square_modulus_fp64(vector1);
    const double square_modulus2 = bgc_vector2_get_square_modulus_fp64(vector2);

    if (square_modulus1 <= BGC_SQUARE_EPSYLON_FP64 || square_modulus2 <= BGC_SQUARE_EPSYLON_FP64) {
        return BGC_ATTITUDE_ZERO;
    }

    const double square_limit = BGC_SQUARE_EPSYLON_FP64 * square_modulus1 * square_modulus2;

    const double scalar_product = bgc_vector2_get_scalar_product_fp64(vector1, vector2);

    if (scalar_product * scalar_product <= square_limit) {
        return BGC_ATTITUDE_ORTHOGONAL;
    }

    const double cross_product = bgc_vector2_get_cross_product_fp64(vector1, vector2);

    if (cross_product * cross_product > square_limit) {
        return BGC_ATTITUDE_ANY;
    }

    return scalar_product > 0.0 ? BGC_ATTITUDE_CO_DIRECTIONAL : BGC_ATTITUDE_COUNTER_DIRECTIONAL;
}

#endif