#pragma once

#include "hittable.h"
#include "vector3.h"

class sphere : public hittable{
    public:
        sphere(){}
        sphere(point3 cen, double r, shared_ptr<material> m): center(cen), radius(r), mat_ptr(m){};

        virtual bool hit(const ray& r, double t_min, double t_max, hit_record& rec) const override;
    
    public:
        point3 center;
        double radius;
        shared_ptr<material> mat_ptr;
};


bool sphere::hit(const ray& r, double t_min, double t_max, hit_record& rec) const {
    vec3 oc = r.origin() - center;
    auto a = r.direction().length_squared();
    auto half_b = dot(oc, r.direction());
    auto c = oc.length_squared() - radius*radius;

    auto discriminant = half_b*half_b - a*c;
    if(discriminant < 0) return false;
    auto sqrtd = sqrt(discriminant);

    // Find the nearest root that lies in the acceptable range
    auto root = (-half_b - sqrtd) /a;
    if(root < t_min || t_max < root){
        root = (-half_b + sqrtd) /a;
        if (root < t_min || t_max < root)
         return false;
    }

    rec.t = root;
    rec.p = r.at(rec.t);
    vec3 outward_normal = (rec.p - center) /radius;
    rec.set_face_normal(r, outward_normal);
    rec.mat_ptr = mat_ptr;
    
    return true;
}