using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace RaytracerEngine
{
    class camera
    {
        vec3 origin;
        vec3 lower_left_corner;
        vec3 horizontal;
        vec3 vertical;
        private const float scale = 0.1f;

        public camera()
        {
            origin = new vec3(0, 0, 0);
            lower_left_corner = new vec3(-2.0f, -1.0f, -1.0f);
            horizontal = new vec3(4.0f, 0.0f, 0.0f);
            vertical = new vec3(0.0f, 2.0f, 0.0f);
        }

        public ray get_ray(float u, float v) { return new ray(origin, lower_left_corner + u*horizontal + v*vertical - origin); }

        public void turn_left()
        {
            //rotational matrix on camera left 25*
            lower_left_corner = vec3.turn_y(lower_left_corner, 25);
            horizontal = vec3.turn_y(horizontal, 25);
            vertical = vec3.turn_y(vertical, 25);
        }

        public void turn_right()
        {
            //rotational matrix on camera right 25*
            lower_left_corner = vec3.turn_y(lower_left_corner, -25);
            horizontal = vec3.turn_y(horizontal, -25);
            vertical = vec3.turn_y(vertical, -25);
        }

        public void strafe_left()
        {
            vec3 forwards_back = vec3.cross(horizontal, vertical);
            forwards_back.normalize();
            vec3 left_right = vec3.cross(vertical, forwards_back);
            left_right.normalize();
            origin = origin - left_right * scale;
        }

        public void strafe_right()
        {
            vec3 forwards_back = vec3.cross(horizontal, vertical);
            forwards_back.normalize();
            vec3 left_right = vec3.cross(vertical, forwards_back);
            left_right.normalize();
            origin = origin + left_right * scale;
        }

        public void fore()
        {
            vec3 forwards_back = vec3.cross(horizontal, vertical);
            forwards_back.normalize();
            origin = origin - forwards_back * scale;
        }

        public void back()
        {
            vec3 forwards_back = vec3.cross(horizontal, vertical);
            forwards_back.normalize();
            origin = origin + forwards_back * scale;
        }
    }
}