#include "color.h"
#include "ray.h"
#include "vector3.h"

#include <iostream>

color ray_color(const ray& r){
    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);


    // Camera
    auto viewport_height = 2.0;
    auto viewport_width = aspect_ratio * viewport_height;
    auto focal_length = 1.0;

    auto origin = point3(0,0,0);
    auto horizontal = vec3(viewport_width, 0, 0);
    auto vertical = vec3(0, viewport_height, 0);
    auto lower_left_corner = origin - horizontal/2 - vertical/2 - vec3(0,0,focal_length);

    // 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)
        {
            auto u = double(i) / (image_width-1);
            auto v = double(j) / (image_height-1);
            ray r(origin, lower_left_corner+u*horizontal + v* vertical -origin);
           color pixel_color = ray_color(r);
           write_color(std::cout , pixel_color);
        }
    }

    std::cerr << "\nDone.\n";
    return 0;
}