#include "Subtract.h"
#include <iostream>
using namespace std;

Subtract::Subtract(refptr<Shape> shape1, refptr<Shape> shape2)
{
    m_shape1 = shape1;
    m_shape2 = shape2;
}

Shape::IntersectionList Subtract::intersect(refptr<Shape> _this, const Ray & ray)
{
    IntersectionList res1 = m_shape1->intersect(m_shape1, ray);
    IntersectionList res2 = m_shape2->intersect(m_shape2, ray);
    BoolIntersectionList merged(res1, res2, ray.getOrigin());

    IntersectionList res;
    bool in1 = false, in2 = false;
    bool in_bool = false;

    for (int i = 0, sz = merged.size(); i < sz; i++)
    {
        Vector normal = merged[i].intersection.normal;
        double dot = - (ray.getDirection() % normal);
        bool front = dot > 0.0;
        bool left = merged[i].left;
        if (left)
            in1 = front;
        else
            in2 = front;
        if (!in_bool && in1 && !in2)
        {
            /* we found an intersection point
             * to get into the boolean object */
            in_bool = true;
            BoolIntersection bi = merged[i];
            Intersection i = bi.intersection;
            if ( ! left )   /* if this point came from object B (A - B) */
                i.normal = - i.normal;
            res.add(i);
        }
        else if (in_bool && !(in1 && !in2))
        {
            /* we found an intersection point
             * to get out of the boolean object */
            BoolIntersection bi = merged[i];
            Intersection i = bi.intersection;
            if ( ! left )   /* if this point came from object B (A - B) */
                i.normal = - i.normal;
            res.add(i);
            in_bool = false;
        }
    }

    return res;
}