extern crate image;

mod camera;
mod color;
mod hittable;
mod hittable_list;
mod ray;
mod utility;
mod vec3;

use camera::Camera;
use hittable::{HitRecord, Hittable, Sphere};
use hittable_list::HittableList;
use image::{Rgb, RgbImage};
use ray::Ray;
use rayon::prelude::*;
use std::env;
use std::sync::atomic::{AtomicU32, Ordering};
use std::sync::Arc;
use vec3::{Color, Point3, Vec3};

fn ray_color(r: &Ray, world: &HittableList, depth: u32) -> Color {
    let mut rec = HitRecord::empty();

    if depth <= 0 {
        return Color::new(0.0, 0.0, 0.0);
    }

    if world.hit(r, 0.0, f64::INFINITY, &mut rec) {
        let target = rec.p + rec.normal + Vec3::random_unit_vector(); // rec.p + rec.normal.random_in_hemisphere();
        return 0.5 * ray_color(&Ray::new(rec.p, target - rec.p), world, depth - 1);
    }
    let unit_direction = r.direction();
    let t = 0.5 * (unit_direction.y() + 1.0);
    return (1.0 - t) * Color::new(1.0, 1.0, 1.0) + t * Color::new(0.5, 0.7, 1.0);
}

fn main() {
    // File
    let mut default_file = "image.ppm";

    // Image
    let aspect_ratio = 16.0 / 9.0;
    let image_width = 1000;
    let image_height = (image_width as f64 / aspect_ratio) as u32;
    let samples_per_pixel = 50_u32;
    let max_depth = 50;

    // World
    let mut world = HittableList::new();
    world.add(Box::<Sphere>::new(Sphere::new(
        Point3::new(0.0, 0.0, -1.0),
        0.5,
    )));
    world.add(Box::<Sphere>::new(Sphere::new(
        Point3::new(0.0, -100.5, -1.0),
        100.0,
    )));
    world.add(Box::<Sphere>::new(Sphere::new(
        Point3::new(1.0, 0.0, -1.5),
        0.3,
    )));
    world.add(Box::<Sphere>::new(Sphere::new(
        Point3::new(1.0, 1.1, -1.5),
        0.3,
    )));
    world.add(Box::<Sphere>::new(Sphere::new(
        Point3::new(-1.0, 1.1, -1.5),
        0.3,
    )));

    /*
    for i in -15..15 {
        for j in -15..15 {
            world.add(Box::<Sphere>::new(Sphere::new(Point3::new(j as f64/5.0 as f64, i as f64/5.0 as f64, -1.5), 0.08)));
        }
    }
    */

    // Camera
    let cam = Camera::new();

    // Render
    let args: Vec<String> = env::args().collect();
    if args.len() > 1 && args[1] != "" {
        default_file = &args[1];
    }

    let mut image = RgbImage::new(image_width, image_height);

    let atomic_counter = Arc::new(AtomicU32::new(0));
    let color_lines: Vec<_> = (0..image_height)
        .into_par_iter()
        .rev()
        .map(|j| {
            let v = atomic_counter.fetch_add(1, Ordering::Relaxed);
            eprint!("\rScanlines remaining: {:5}", image_height - v);

            let mut colors = Vec::new();
            for i in 0..image_width {
                let mut pixel_color = Color::new(0.0, 0.0, 0.0);
                for _ in 0..samples_per_pixel {
                    let u = (i as f64 + utility::random_f64()) / (image_width - 1) as f64;
                    let v = (j as f64 + utility::random_f64()) / (image_height - 1) as f64;
                    let r = cam.get_ray(u, v);
                    pixel_color += ray_color(&r, &world, max_depth);
                }
                colors.push(pixel_color);
            }
            return colors;
        })
        .collect();
    eprint!("\rScanlines remaining: {:5}", 0);

    (0..image_height).into_iter().rev().for_each(|j| {
        (0..image_width).into_iter().for_each(|i| {
            color::put_color(
                &mut image,
                &color_lines[(image_height - j - 1) as usize][i as usize],
                i,
                image_height - j - 1,
                samples_per_pixel,
            );
        })
    });

    image.save(default_file).unwrap();
    eprintln!("\nDone!");
}