#ifndef _BGC_VECTOR2_H_
#define _BGC_VECTOR2_H_

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

#include <math.h>

typedef struct
{
    float x1, x2;
} BGC_FP32_Vector2;

typedef struct
{
    double x1, x2;
} BGC_FP64_Vector2;

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

inline void bgc_fp32_vector2_reset(BGC_FP32_Vector2* vector)
{
    vector->x1 = 0.0f;
    vector->x2 = 0.0f;
}

inline void bgc_fp64_vector2_reset(BGC_FP64_Vector2* vector)
{
    vector->x1 = 0.0;
    vector->x2 = 0.0;
}

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

inline void bgc_fp32_vector2_make(BGC_FP32_Vector2* destination, const float x1, const float x2)
{
    destination->x1 = x1;
    destination->x2 = x2;
}

inline void bgc_fp64_vector2_make(BGC_FP64_Vector2* destination, const double x1, const double x2)
{
    destination->x1 = x1;
    destination->x2 = x2;
}

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

inline float bgc_fp32_vector2_get_square_modulus(const BGC_FP32_Vector2* vector)
{
    return vector->x1 * vector->x1 + vector->x2 * vector->x2;
}

inline double bgc_fp64_vector2_get_square_modulus(const BGC_FP64_Vector2* vector)
{
    return vector->x1 * vector->x1 + vector->x2 * vector->x2;
}

inline float bgc_fp32_vector2_get_modulus(const BGC_FP32_Vector2* vector)
{
    return sqrtf(bgc_fp32_vector2_get_square_modulus(vector));
}

inline double bgc_fp64_vector2_get_modulus(const BGC_FP64_Vector2* vector)
{
    return sqrt(bgc_fp64_vector2_get_square_modulus(vector));
}

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

inline int bgc_fp32_vector2_is_zero(const BGC_FP32_Vector2* vector)
{
    return bgc_fp32_vector2_get_square_modulus(vector) <= BGC_FP32_SQUARE_EPSYLON;
}

inline int bgc_fp64_vector2_is_zero(const BGC_FP64_Vector2* vector)
{
    return bgc_fp64_vector2_get_square_modulus(vector) <= BGC_FP64_SQUARE_EPSYLON;
}

inline int bgc_fp32_vector2_is_unit(const BGC_FP32_Vector2* vector)
{
    return bgc_fp32_is_square_unit(bgc_fp32_vector2_get_square_modulus(vector));
}

inline int bgc_fp64_vector2_is_unit(const BGC_FP64_Vector2* vector)
{
    return bgc_fp64_is_square_unit(bgc_fp64_vector2_get_square_modulus(vector));
}

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

inline void bgc_fp32_vector2_copy(BGC_FP32_Vector2* destination, const BGC_FP32_Vector2* source)
{
    destination->x1 = source->x1;
    destination->x2 = source->x2;
}

inline void bgc_fp64_vector2_copy(BGC_FP64_Vector2* destination, const BGC_FP64_Vector2* source)
{
    destination->x1 = source->x1;
    destination->x2 = source->x2;
}

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

inline void bgc_fp32_vector2_swap(BGC_FP32_Vector2* vector1, BGC_FP32_Vector2* 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_fp64_vector2_swap(BGC_FP64_Vector2* vector1, BGC_FP64_Vector2* 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_fp32_vector2_convert_to_fp64(BGC_FP64_Vector2* destination, const BGC_FP32_Vector2* source)
{
    destination->x1 = source->x1;
    destination->x2 = source->x2;
}

inline void bgc_fp64_vector2_convert_to_fp32(BGC_FP32_Vector2* destination, const BGC_FP64_Vector2* source)
{
    destination->x1 = (float)source->x1;
    destination->x2 = (float)source->x2;
}

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

inline void bgc_fp32_vector2_add(BGC_FP32_Vector2* sum, const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    sum->x1 = vector1->x1 + vector2->x1;
    sum->x2 = vector1->x2 + vector2->x2;
}

inline void bgc_fp64_vector2_add(BGC_FP64_Vector2* sum, const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    sum->x1 = vector1->x1 + vector2->x1;
    sum->x2 = vector1->x2 + vector2->x2;
}

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

inline void bgc_fp32_vector2_add_scaled(BGC_FP32_Vector2* sum, const BGC_FP32_Vector2* basic_vector, const BGC_FP32_Vector2* scalable_vector, const float scale)
{
    sum->x1 = basic_vector->x1 + scalable_vector->x1 * scale;
    sum->x2 = basic_vector->x2 + scalable_vector->x2 * scale;
}

inline void bgc_fp64_vector2_add_scaled(BGC_FP64_Vector2* sum, const BGC_FP64_Vector2* basic_vector, const BGC_FP64_Vector2* scalable_vector, const double scale)
{
    sum->x1 = basic_vector->x1 + scalable_vector->x1 * scale;
    sum->x2 = basic_vector->x2 + scalable_vector->x2 * scale;
}

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

inline void bgc_fp32_vector2_subtract(BGC_FP32_Vector2* difference, const BGC_FP32_Vector2* minuend, const BGC_FP32_Vector2* subtrahend)
{
    difference->x1 = minuend->x1 - subtrahend->x1;
    difference->x2 = minuend->x2 - subtrahend->x2;
}

inline void bgc_fp64_vector2_subtract(BGC_FP64_Vector2* difference, const BGC_FP64_Vector2* minuend, const BGC_FP64_Vector2* subtrahend)
{
    difference->x1 = minuend->x1 - subtrahend->x1;
    difference->x2 = minuend->x2 - subtrahend->x2;
}

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

inline void bgc_fp32_vector2_multiply(BGC_FP32_Vector2* product, const BGC_FP32_Vector2* multiplicand, const float multiplier)
{
    product->x1 = multiplicand->x1 * multiplier;
    product->x2 = multiplicand->x2 * multiplier;
}

inline void bgc_fp64_vector2_multiply(BGC_FP64_Vector2* product, const BGC_FP64_Vector2* multiplicand, const double multiplier)
{
    product->x1 = multiplicand->x1 * multiplier;
    product->x2 = multiplicand->x2 * multiplier;
}

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

inline void bgc_fp32_vector2_divide(BGC_FP32_Vector2* quotient, const BGC_FP32_Vector2* dividend, const float divisor)
{
    bgc_fp32_vector2_multiply(quotient, dividend, 1.0f / divisor);
}

inline void bgc_fp64_vector2_divide(BGC_FP64_Vector2* quotient, const BGC_FP64_Vector2* dividend, const double divisor)
{
    bgc_fp64_vector2_multiply(quotient, dividend, 1.0 / divisor);
}

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

inline void bgc_fp32_vector2_get_mean2(BGC_FP32_Vector2* mean, const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    mean->x1 = (vector1->x1 + vector2->x1) * 0.5f;
    mean->x2 = (vector1->x2 + vector2->x2) * 0.5f;
}

inline void bgc_fp64_vector2_get_mean2(BGC_FP64_Vector2* mean, const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    mean->x1 = (vector1->x1 + vector2->x1) * 0.5;
    mean->x2 = (vector1->x2 + vector2->x2) * 0.5;
}

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

inline void bgc_fp32_vector2_get_mean3(BGC_FP32_Vector2* mean, const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2, const BGC_FP32_Vector2* vector3)
{
    mean->x1 = (vector1->x1 + vector2->x1 + vector3->x1) * BGC_FP32_ONE_THIRD;
    mean->x2 = (vector1->x2 + vector2->x2 + vector3->x2) * BGC_FP32_ONE_THIRD;
}

inline void bgc_fp64_vector2_get_mean3(BGC_FP64_Vector2* mean, const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2, const BGC_FP64_Vector2* vector3)
{
    mean->x1 = (vector1->x1 + vector2->x1 + vector3->x1) * BGC_FP64_ONE_THIRD;
    mean->x2 = (vector1->x2 + vector2->x2 + vector3->x2) * BGC_FP64_ONE_THIRD;
}

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

inline void bgc_fp32_vector2_interpolate(BGC_FP32_Vector2* interpolation, const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2, const float phase)
{
    const float counter_phase = 1.0f - phase;

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

inline void bgc_fp64_vector2_interpolate(BGC_FP64_Vector2* interpolation, const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2, const double phase)
{
    const double counter_phase = 1.0 - phase;

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

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

inline void bgc_fp32_vector2_revert(BGC_FP32_Vector2* vector)
{
    vector->x1 = -vector->x1;
    vector->x2 = -vector->x2;
}

inline void bgc_fp64_vector2_revert(BGC_FP64_Vector2* vector)
{
    vector->x1 = -vector->x1;
    vector->x2 = -vector->x2;
}

inline void bgc_fp32_vector2_get_reverse(BGC_FP32_Vector2* reverse, const BGC_FP32_Vector2* vector)
{
    reverse->x1 = -vector->x1;
    reverse->x2 = -vector->x2;
}

inline void bgc_fp64_vector2_get_reverse(BGC_FP64_Vector2* reverse, const BGC_FP64_Vector2* vector)
{
    reverse->x1 = -vector->x1;
    reverse->x2 = -vector->x2;
}

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

inline int bgc_fp32_vector2_normalize(BGC_FP32_Vector2* vector)
{
    const float square_modulus = bgc_fp32_vector2_get_square_modulus(vector);

    if (bgc_fp32_is_square_unit(square_modulus)) {
        return 1;
    }

    if (square_modulus <= BGC_FP32_SQUARE_EPSYLON || isnan(square_modulus)) {
        return 0;
    }

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

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

    return 1;
}

inline int bgc_fp64_vector2_normalize(BGC_FP64_Vector2* vector)
{
    const double square_modulus = bgc_fp64_vector2_get_square_modulus(vector);

    if (bgc_fp64_is_square_unit(square_modulus)) {
        return 1;
    }

    if (square_modulus <= BGC_FP64_SQUARE_EPSYLON || isnan(square_modulus)) {
        return 0;
    }

    const double multiplier = sqrt(1.0 / square_modulus);

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

    return 1;
}

inline int bgc_fp32_vector2_get_normalized(BGC_FP32_Vector2* normalized, const BGC_FP32_Vector2* vector)
{
    const float square_modulus = bgc_fp32_vector2_get_square_modulus(vector);

    if (bgc_fp32_is_square_unit(square_modulus)) {
        bgc_fp32_vector2_copy(normalized, vector);
        return 1;
    }

    if (square_modulus <= BGC_FP32_SQUARE_EPSYLON || isnan(square_modulus)) {
        bgc_fp32_vector2_reset(normalized);
        return 0;
    }

    bgc_fp32_vector2_multiply(normalized, vector, sqrtf(1.0f / square_modulus));
    return 1;
}

inline int bgc_fp64_vector2_get_normalized(BGC_FP64_Vector2* normalized, const BGC_FP64_Vector2* vector)
{
    const double square_modulus = bgc_fp64_vector2_get_square_modulus(vector);

    if (bgc_fp64_is_square_unit(square_modulus)) {
        bgc_fp64_vector2_copy(normalized, vector);
        return 1;
    }

    if (square_modulus <= BGC_FP64_SQUARE_EPSYLON || isnan(square_modulus)) {
        bgc_fp64_vector2_reset(normalized);
        return 0;
    }

    bgc_fp64_vector2_multiply(normalized, vector, sqrt(1.0 / square_modulus));
    return 1;
}

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

inline float bgc_fp32_vector2_get_dot_product(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    return vector1->x1 * vector2->x1 + vector1->x2 * vector2->x2;
}

inline double bgc_fp64_vector2_get_dot_product(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    return vector1->x1 * vector2->x1 + vector1->x2 * vector2->x2;
}

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

inline float bgc_fp32_vector2_get_cross_product(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    return vector1->x1 * vector2->x2 - vector1->x2 * vector2->x1;
}

inline double bgc_fp64_vector2_get_cross_product(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    return vector1->x1 * vector2->x2 - vector1->x2 * vector2->x1;
}

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

float bgc_fp32_vector2_get_angle(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2, const int angle_unit);

double bgc_fp64_vector2_get_angle(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2, const int angle_unit);

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

inline float bgc_fp32_vector2_get_square_distance(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    const float dx1 = vector1->x1 - vector2->x1;
    const float dx2 = vector1->x2 - vector2->x2;

    return dx1 * dx1 + dx2 * dx2;
}

inline double bgc_fp64_vector2_get_square_distance(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    const double dx1 = vector1->x1 - vector2->x1;
    const double dx2 = vector1->x2 - vector2->x2;

    return dx1 * dx1 + dx2 * dx2;
}

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

inline float bgc_fp32_vector2_get_distance(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    return sqrtf(bgc_fp32_vector2_get_square_distance(vector1, vector2));
}

inline double bgc_fp64_vector2_get_distance(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    return sqrt(bgc_fp64_vector2_get_square_distance(vector1, vector2));
}

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

inline int bgc_fp32_vector2_are_close_enough(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2, const float distance_limit)
{
    return bgc_fp32_vector2_get_square_distance(vector1, vector2) <= distance_limit * distance_limit;
}

inline int bgc_fp64_vector2_are_close_enough(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2, const double distance_limit)
{
    return bgc_fp64_vector2_get_square_distance(vector1, vector2) <= distance_limit * distance_limit;
}

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

inline int bgc_fp32_vector2_are_close(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    const float square_modulus1 = bgc_fp32_vector2_get_square_modulus(vector1);
    const float square_modulus2 = bgc_fp32_vector2_get_square_modulus(vector2);
    const float square_distance = bgc_fp32_vector2_get_square_distance(vector1, vector2);

    if (square_modulus1 <= BGC_FP32_EPSYLON_EFFECTIVENESS_LIMIT || square_modulus2 <= BGC_FP32_EPSYLON_EFFECTIVENESS_LIMIT) {
        return square_distance <= BGC_FP32_SQUARE_EPSYLON;
    }

    return square_distance <= BGC_FP32_SQUARE_EPSYLON * square_modulus1 && square_distance <= BGC_FP32_SQUARE_EPSYLON * square_modulus2;
}

inline int bgc_fp64_vector2_are_close(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    const double square_modulus1 = bgc_fp64_vector2_get_square_modulus(vector1);
    const double square_modulus2 = bgc_fp64_vector2_get_square_modulus(vector2);
    const double square_distance = bgc_fp64_vector2_get_square_distance(vector1, vector2);

    if (square_modulus1 <= BGC_FP64_EPSYLON_EFFECTIVENESS_LIMIT || square_modulus2 <= BGC_FP64_EPSYLON_EFFECTIVENESS_LIMIT) {
        return square_distance <= BGC_FP64_SQUARE_EPSYLON;
    }

    return square_distance <= BGC_FP64_SQUARE_EPSYLON * square_modulus1 && square_distance <= BGC_FP64_SQUARE_EPSYLON * square_modulus2;
}


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

inline int bgc_fp32_vector2_are_parallel(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    const float square_modulus1 = bgc_fp32_vector2_get_square_modulus(vector1);

    if (square_modulus1 <= BGC_FP32_SQUARE_EPSYLON) {
        return 1;
    }

    const float square_modulus2 = bgc_fp32_vector2_get_square_modulus(vector2);

    if (square_modulus2 <= BGC_FP32_SQUARE_EPSYLON) {
        return 1;
    }

    const float cross_product = bgc_fp32_vector2_get_cross_product(vector1, vector2);

    return cross_product * cross_product <= BGC_FP32_SQUARE_EPSYLON * square_modulus1 * square_modulus2;
}

inline int bgc_fp64_vector2_are_parallel(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    const double square_modulus1 = bgc_fp64_vector2_get_square_modulus(vector1);

    if (square_modulus1 <= BGC_FP64_SQUARE_EPSYLON) {
        return 1;
    }

    const double square_modulus2 = bgc_fp64_vector2_get_square_modulus(vector2);

    if (square_modulus2 <= BGC_FP64_SQUARE_EPSYLON) {
        return 1;
    }

    const double cross_product = bgc_fp64_vector2_get_cross_product(vector1, vector2);

    return cross_product * cross_product <= BGC_FP64_SQUARE_EPSYLON * square_modulus1 * square_modulus2;
}

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

inline int bgc_fp32_vector2_are_orthogonal(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    const float square_modulus1 = bgc_fp32_vector2_get_square_modulus(vector1);

    if (square_modulus1 <= BGC_FP32_SQUARE_EPSYLON) {
        return 1;
    }

    const float square_modulus2 = bgc_fp32_vector2_get_square_modulus(vector2);

    if (square_modulus2 <= BGC_FP32_SQUARE_EPSYLON) {
        return 1;
    }

    const float scalar_product = bgc_fp32_vector2_get_dot_product(vector1, vector2);

    return scalar_product * scalar_product <= BGC_FP32_SQUARE_EPSYLON * square_modulus1 * square_modulus2;
}

inline int bgc_fp64_vector2_are_orthogonal(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    const double square_modulus1 = bgc_fp64_vector2_get_square_modulus(vector1);

    if (square_modulus1 <= BGC_FP64_SQUARE_EPSYLON) {
        return 1;
    }

    const double square_modulus2 = bgc_fp64_vector2_get_square_modulus(vector2);

    if (square_modulus2 <= BGC_FP64_SQUARE_EPSYLON) {
        return 1;
    }

    const double scalar_product = bgc_fp64_vector2_get_dot_product(vector1, vector2);

    return scalar_product * scalar_product <= BGC_FP64_SQUARE_EPSYLON * square_modulus1 * square_modulus2;
}


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

inline int bgc_fp32_vector2_get_attitude(const BGC_FP32_Vector2* vector1, const BGC_FP32_Vector2* vector2)
{
    const float square_modulus1 = bgc_fp32_vector2_get_square_modulus(vector1);
    const float square_modulus2 = bgc_fp32_vector2_get_square_modulus(vector2);

    if (square_modulus1 <= BGC_FP32_SQUARE_EPSYLON || square_modulus2 <= BGC_FP32_SQUARE_EPSYLON) {
        return BGC_ATTITUDE_ZERO;
    }

    const float square_limit = BGC_FP32_SQUARE_EPSYLON * square_modulus1 * square_modulus2;

    const float scalar_product = bgc_fp32_vector2_get_dot_product(vector1, vector2);

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

    const float cross_product = bgc_fp32_vector2_get_cross_product(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_fp64_vector2_get_attitude(const BGC_FP64_Vector2* vector1, const BGC_FP64_Vector2* vector2)
{
    const double square_modulus1 = bgc_fp64_vector2_get_square_modulus(vector1);
    const double square_modulus2 = bgc_fp64_vector2_get_square_modulus(vector2);

    if (square_modulus1 <= BGC_FP64_SQUARE_EPSYLON || square_modulus2 <= BGC_FP64_SQUARE_EPSYLON) {
        return BGC_ATTITUDE_ZERO;
    }

    const double square_limit = BGC_FP64_SQUARE_EPSYLON * square_modulus1 * square_modulus2;

    const double scalar_product = bgc_fp64_vector2_get_dot_product(vector1, vector2);

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

    const double cross_product = bgc_fp64_vector2_get_cross_product(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