#include "rtweekend.h"

#include "color.h"
#include "hittable_list.h"
#include "sphere.h"
#include "camera.h"

#include <iostream>

color ray_color(const ray& r, const hittable& world, int depth) {
	hit_record rec;

	// If we've exceeded the ray bounce limit, no more light is gathered.
	if (depth <= 0)
		return color(0, 0, 0);

	if (world.hit(r, 0.001, infinity, rec)) {
		point3 target = rec.p + rec.normal + random_in_hemisphere(rec.normal);
		return 0.5 * ray_color(ray(rec.p, target - rec.p), world, depth-1);
	}

	vec3 unit_direction = unit_vector(r.direction());
	auto t = 0.5*(unit_direction.y() + 1.0);
	return (1.0 - t)*color(1.0, 1.0, 1.0) + t*color(0.5, 0.7, 1.0);
}

int main() {
	// Image
	const auto aspect_ratio = 16.0 / 9.0;
	const int image_width = 400;
	const int image_height = static_cast<int>(image_width / aspect_ratio);
	const int samples_per_pixel = 16;
	const int max_depth = 25;

	// World
	hittable_list world;
	world.add(make_shared<sphere>(point3(0, 0, -1), 0.5));
	world.add(make_shared<sphere>(point3(0, -100.5, -1), 100));

	// Camera
	camera cam;

	// Render
	std::cout<<"P3\n" <<image_width<<" "<<image_height<<"\n255\n";
	for (int j = image_height-1; j >= 0; --j) {
		std::cerr<<"\rScanlines remaining: "<<j<<" "<<std::flush;
		for (int i = 0; i < image_width; ++i) {
			color pixel_color(0, 0, 0);
			for (int s = 0; s < samples_per_pixel; ++s) {
				auto u = (i + random_double()) / (image_width-1);
				auto v = (j + random_double()) / (image_height-1);
				ray r = cam.get_ray(u, v);
				pixel_color += ray_color(r, world, max_depth);
			}
			write_color(std::cout, pixel_color, samples_per_pixel);
		}
	}
	std::cerr<<"\nDone.\n";
}