#![allow(clippy::many_single_char_names)]

use crate::{colors::generate_palette, texture::Texture, vec3::Vec3};

#[derive(Debug)]
pub struct Mandelbrot {
    palette: Vec<Vec3>,
}

impl Default for Mandelbrot {
    fn default() -> Self {
        Mandelbrot {
            palette: generate_palette(10),
        }
    }
}

impl Texture for Mandelbrot {
    fn value(&self, u: f32, v: f32, _p: Vec3) -> Vec3 {
        // scaled x coordinate of pixel (scaled to lie in the Mandelbrot X scale (-2.5, 1))
        let x0 = u * 3.5 - 2.5;
        // scaled y coordinate of pixel (scaled to lie in the Mandelbrot Y scale (-1, 1))
        let y0 = v * 2.0 - 1.0;
        let mut x = 0.0;
        let mut y = 0.0;
        let mut iteration = 0;
        let max_iteration = 1000;
        while (x * x + y * y) <= 2. * 2. && iteration < max_iteration {
            let xtemp = x * x - y * y + x0;
            y = 2. * x * y + y0;
            x = xtemp;
            iteration += 1;
        }
        if iteration == max_iteration {
            return Vec3::default();
        }
        self.palette[iteration % self.palette.len()]
    }
}