#ifndef MATERIAL_H
#define MATERIAL_H

#include "rtweekend.hpp"

struct material {
    virtual bool scatter(const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered) const = 0;
};

struct lambertian : material {
    /* Attributes */
    color albedo;
    // Constructor
    lambertian(const color& c) { albedo = c; }

    #pragma GCC diagnostic push
    #pragma GCC diagnostic ignored "-Wunused-parameter"
    virtual bool scatter(const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered) const override
    {
        vec3 scatter_direction = rec.normal + random_unit_vector();

        /* NOTE: it is possible that the random vector we generate is exactly opposite to the normal vector,
           in which case it will sum to a near-zero scatter vector and generate degenerate results.
           We check for near-zero vectors here.
         */

        if (scatter_direction.near_zero())
            scatter_direction = rec.normal;         
        
        scattered = ray(rec.p, scatter_direction);
        attenuation = albedo;
        return true;
    }
    #pragma GCC diagnostic pop
};

struct metal : material {
    /* Attributes */
    color albedo;
    // Constructor
    metal(const color& c) { albedo = c; };

    virtual bool scatter(const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered) const override
    {
        vec3 reflected = reflect(normalize(r_in.direction), rec.normal);
        scattered = ray(rec.p, reflected);
        attenuation = albedo;
        return (dot(scattered.direction, rec.normal) > 0);
    }
};

#endif