#version 330 core
out vec4 frag_color;

uniform vec3 light_pos;
uniform vec4 solid_color;
uniform vec3 camera;

in vec3 normal;
in vec3 frag_position;
 
void main() {
    vec4 light_color = vec4(1, 1, 1, 1);
    vec3 normal_norm = normalize(normal);
    vec3 light_direction_norm = normalize(light_pos - frag_position);

    float ambient_strength = 0.15;
    vec4 ambient = ambient_strength * light_color;

    float diffuse_strength = max(dot(normal_norm, light_direction_norm), 0.0);
    vec4 diffuse = diffuse_strength * light_color;

    float specular_strength = 0.9;
    vec3 view_direction_norm = normalize(camera - frag_position);
    vec3 reflect_dir = reflect(-light_direction_norm, normal_norm);
    float spec = pow(max(dot(view_direction_norm, reflect_dir), 0.0), 32);
    vec4 specular = specular_strength * spec * light_color;

    frag_color = specular + (ambient + diffuse) * solid_color;
}