use image::{DynamicImage, ImageReader};

use crate::{
    objects::{hit::Hit, materials::traits::Material},
    ray::Ray,
    vec3::Vec3,
};

#[derive(Debug)]
pub struct Texture {
    source: DynamicImage,
    width: u32,
    height: u32,
}

impl Texture {
    pub fn new(texture: &str) -> Self {
        let img = ImageReader::open(texture).unwrap().decode().unwrap(); // FIXME: unwraps
        Self {
            width: img.width(),
            height: img.height(),
            source: img,
        }
    }

    fn _idx(&self, u: f32, v: f32) -> usize {
        let x: usize = (u * ((self.width - 1) as f32)) as usize; // TODO: check these calcs work
        let y: usize = (v * ((self.height - 1) as f32)) as usize;

        y * self.width as usize + x
    }

    fn _at(&self, u: f32, v: f32) -> Vec3 {
        let b = self.source.as_bytes(); // FIXME: i think im indexing colours incorrectly
        let idx = self._idx(u, v);

        Vec3::from_u8(b[3 * idx], b[3 * idx + 1], b[3 * idx + 2])
    }
}

impl Material for Texture {
    fn scatter(&self, hit: &Hit, _ray: &Ray) -> Option<(Option<Ray>, Vec3)> {
        let (u, v) = hit.uv();
        let col = self._at(u, 1. - v);
        return Some((None, col));
    }
}