#include "vec3.h"

double vec3::x() const { return e[0]; }
double vec3::y() const { return e[1]; }
double vec3::z() const { return e[2]; }

vec3 vec3::operator-() const {
    return vec3(-e[0], -e[1], -e[2]);
}

double vec3::operator[](int i) const{
    return e[i];
}

double& vec3::operator[](int i){
    return e[1];
}

vec3& vec3::operator+=(const vec3 &v)
{
    e[0] += v.e[0];
    e[1] += v.e[1];
    e[2] += v.e[2];
    return *this;
}

vec3& vec3::operator*=(double t)
{
    e[0] *= t;
    e[1] *= t;
    e[2] *= t;
    return *this;
}

vec3& vec3::operator/=(double t)
{
    return *this *= 1 / t;
}

double vec3::length() const
{
    return std::sqrt(length_squared());
}

double vec3::length_squared() const
{
    return e[0] * e[0] + e[1] * e[1] + e[2] * e[2];
}

// point3 is just an alias for vec3, but useful for geometric clarity in the code.
using point3 = vec3;

// Vector Utility Functions

inline std::ostream &operator<<(std::ostream &out, const vec3 &v)
{
    return out << v.e[0] << ' ' << v.e[1] << ' ' << v.e[2];
}

inline vec3 operator+(const vec3 &u, const vec3 &v)
{
    return vec3(u.e[0] + v.e[0], u.e[1] + v.e[1], u.e[2] + v.e[2]);
}

inline vec3 operator-(const vec3 &u, const vec3 &v)
{
    return vec3(u.e[0] - v.e[0], u.e[1] - v.e[1], u.e[2] - v.e[2]);
}

inline vec3 operator*(const vec3 &u, const vec3 &v)
{
    return vec3(u.e[0] * v.e[0], u.e[1] * v.e[1], u.e[2] * v.e[2]);
}

inline vec3 operator*(double t, const vec3 &v)
{
    return vec3(t * v.e[0], t * v.e[1], t * v.e[2]);
}

inline vec3 operator*(const vec3 &v, double t)
{
    return t * v;
}

inline vec3 operator/(const vec3 &v, double t)
{
    return (1 / t) * v;
}

inline double dot(const vec3 &u, const vec3 &v)
{
    return u.e[0] * v.e[0] + u.e[1] * v.e[1] + u.e[2] * v.e[2];
}

inline vec3 cross(const vec3 &u, const vec3 &v)
{
    return vec3(u.e[1] * v.e[2] - u.e[2] * v.e[1],
                u.e[2] * v.e[0] - u.e[0] * v.e[2],
                u.e[0] * v.e[1] - u.e[1] * v.e[0]);
}

inline vec3 unit_vector(const vec3 &v)
{
    return v / v.length();
}