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use derive_cmp_ops::CmpOps;
use glium::uniforms::AsUniformValue;
use crate::prelude::Mat4;
use super::vec3::{vec3, Vec3};
#[derive(Debug, Clone, Copy, PartialEq, PartialOrd, CmpOps)]
///a vector made from a x, y, z and w coordinate.
pub struct Vec4{
    pub x: f32,
    pub y: f32,
    pub z: f32,
    pub w: f32
}
impl Vec4{
    ///a zero vector
    pub const ZERO: Self = vec4(0.0, 0.0, 0.0, 0.0);
    ///a vector full of ones
    pub const ONE: Self = vec4(1.0, 1.0, 1.0, 1.0);
    ///the x axis
    pub const X: Self = vec4(1.0, 0.0, 0.0, 0.0);
    ///the y axis
    pub const Y: Self = vec4(0.0, 1.0, 0.0, 0.0);
    ///the z axis
    pub const Z: Self = vec4(0.0, 0.0, 1.0, 0.0);
    ///the w axis
    pub const W: Self = vec4(0.0, 0.0, 0.0, 1.0);

    pub fn new(x: f32, y: f32, z: f32, w: f32) -> Self{
        Self { x, y, z, w }
    }
    ///create a vector where x, y and z equals `value`.
    pub fn splat(value: f32) -> Self{
        Self::new(value, value, value, value)
    }
    pub fn truncate(&self) -> Vec3{
        vec3(self.x, self.y, self.z)
    }
    ///the length of the vector before being square rooted.
    pub fn length_squared(self) -> f32{
        self.x*self.x + self.y*self.y + self.z*self.z + self.w*self.w
    }
    ///length of the vector.
    pub fn length(self) -> f32{
        self.length_squared().sqrt()
    }
    ///distance between two vectors before being square rooted.
    pub fn distance_squared(self, other: Vec4) -> f32{
        (self - other).length_squared()
    }
    ///distance between two vectors.
    pub fn distance(self, other: Vec4) -> f32{
        (self - other).length()
    }
    ///get the dot product of 2 vectors. equal to the cosign of the angle between vectors.
    pub fn dot(self, other: Vec4) -> f32{
        self.x * other.x + self.y * other.y + self.z * other.z + self.w * other.w
    }
    ///multiplies each value by the scalar.
    pub fn scale(self, scalar: f32) -> Vec4{
        Self::new(self.x * scalar, self.y * scalar, self.z * scalar, self.w * scalar)
    }
    ///makes the length of the vector equal to 1. on fail returns vec4 of zeros
    pub fn normalise(self) -> Self{
        let length = self.length();
        if length == 0.0 { return vec4(0.0, 0.0, 0.0, 0.0); }
        self.scale(1.0 / length)
    }
    ///transforms vector by the matrix
    pub fn transform(self, matrix: &Mat4) -> Vec4{
        let a: Vec4 = matrix.row(0).into();
        let b: Vec4 = matrix.row(1).into();
        let c: Vec4 = matrix.row(2).into();
        let d: Vec4 = matrix.row(3).into();
        vec4(a.dot(self), b.dot(self), c.dot(self), d.dot(self))
    }
}
impl AsUniformValue for Vec4{
    fn as_uniform_value(&self) -> glium::uniforms::UniformValue<'_> {
        glium::uniforms::UniformValue::Vec4([self.x, self.y, self.z, self.w])
    }
}
impl From<[f32; 4]> for Vec4 {
    fn from(value: [f32; 4]) -> Self {
        Self { x: value[0], y: value[1], z: value[2], w: value[3] }
    }
}
///create a vector with an x, y, z and w coordinate.
pub const fn vec4(x: f32, y: f32, z: f32, w: f32) -> Vec4{
    Vec4 { x, y, z, w }
}