use crate::{Color, Vec3};
use crate::hittable::{HitRecord, HittableList};
use crate::material::Scatterable;
use crate::vec3::Point3;

#[derive(Debug)]
pub struct Ray {
    origin: Point3,
    direction: Vec3,
    time: f64
}
impl Default for Ray {
    fn default() -> Self {
        Ray::new(Vec3::default(), Vec3::default(), 0.0)
    }
}

impl Ray {
    pub fn new(origin: Point3, direction: Point3, time: f64) -> Ray {
        Ray { origin, direction, time }
    }
    pub fn at(&self, t: f64) -> Point3 {
        self.origin + self.direction * t
    }
    pub fn direction(&self) -> Vec3 { self.direction }
    pub fn origin(&self) -> Point3 { self.origin }
    pub fn time(&self) -> f64 { self.time }
    pub fn pixel_color(&self, background: Color, world: &HittableList, depth: i32) -> Color {
        if depth <= 0 {
            return Color::default();
        }
        match self.hit_world(world, 0.001, f64::INFINITY) {
            Some(rect) => {
                let scattered = rect.material.scatter(self, &rect);
                let emitted = rect.material.emitted(rect.u, rect.v, &rect.point);
                match scattered {
                    Some((scattered, albedo)) => {
                        match scattered {
                            Some(scattered) => {
                                emitted + albedo * scattered.pixel_color(background, world, depth-1)
                            },
                            None => albedo
                        }
                    },
                    _ => emitted
                }
            },
            None => background
        }
    }
    pub fn hit_world<'material>(
        &self,
        world: &'material HittableList,
        t_min: f64,
        t_max: f64,
    ) -> Option<HitRecord<'material>> {
        let mut closest_so_far = t_max;
        let mut hit_record = None;
        for sphere in world {
            if let Some(hit) = sphere.hit(self, t_min, closest_so_far) {
                closest_so_far = hit.t;
                hit_record = Some(hit);
            }
        }
        hit_record
    }
}