use std::ops::*;

#[derive(Clone, Copy, Debug)]
pub struct Vec3 {
    pub e: [f64; 3],
}

pub type Color = Vec3;
pub type Point3 = Vec3;

impl Vec3 {
    pub fn new(x: f64, y: f64, z: f64) -> Self {
        Vec3 { e: [x, y, z] }
    }

    pub fn length(&self) -> f64 {
        self.length_squared().sqrt()
    }

    pub fn length_squared(&self) -> f64 { 
        self.e[0]*self.e[0]
        + self.e[1]*self.e[1]
        + self.e[2]*self.e[2]
    }

    pub fn cross(a: Vec3, b: Vec3) -> Vec3 {
        Vec3::new(a.y()*b.z() - a.z()*b.y(),
            a.z()*b.x() - a.x()*b.z(),
            a.x()*b.y() - a.y()*b.x())
    }

    pub fn dot(a: Vec3, b: Vec3) -> f64 {
        a.x()*b.x() + a.y()*b.y() + a.z()*b.z()
    }

    pub fn unit_vector(a: Vec3) -> Vec3 {
        a / a.length()
    }

    pub fn x(&self) -> f64 { self.e[0] }
    pub fn y(&self) -> f64 { self.e[1] }
    pub fn z(&self) -> f64 { self.e[2] }
}

impl Add for Vec3 {
    type Output = Vec3;

    fn add(self, rhs: Self) -> Vec3 {
        Vec3::new(self.x()+rhs.x(), self.y()+rhs.y(), self.z()+rhs.z())
    }
}

impl AddAssign for Vec3 {
    fn add_assign(&mut self, rhs: Self) {
        self.e[0] += rhs.x();
        self.e[1] += rhs.y();
        self.e[2] += rhs.z();
    }
}

impl Sub for Vec3 {
    type Output = Vec3;

    fn sub(self, rhs: Self) -> Vec3 {
        Vec3::new(self.x()-rhs.x(), self.y()-rhs.y(), self.z()-rhs.z())
    }
}

impl SubAssign for Vec3 {
    fn sub_assign(&mut self, rhs: Self) {
        self.e[0] -= rhs.x();
        self.e[1] -= rhs.y();
        self.e[2] -= rhs.z();
    }
}

impl Mul<Vec3> for f64 {
    type Output = Vec3;

    fn mul(self, rhs: Vec3) -> Vec3 {
        Vec3::new(self*rhs.x(), self*rhs.y(), self*rhs.z())
    }
}

impl MulAssign<f64> for Vec3 {
    fn mul_assign(&mut self, rhs: f64) {
        self.e[0] *= rhs;
        self.e[1] *= rhs;
        self.e[2] *= rhs;
    }
}

impl DivAssign<f64> for Vec3 {
    fn div_assign(&mut self, rhs: f64) {
        self.e[0] /= rhs;
        self.e[1] /= rhs;
        self.e[2] /= rhs;
    }
}

impl Div<f64> for Vec3 {
    type Output = Vec3;

    fn div(self, rhs: f64) -> Vec3 {
        Vec3::new(self.x()/rhs, self.y()/rhs, self.z()/rhs)
    }
}