#ifndef POLYGON_H
#define POLYGON_H

#include "fastmath.hpp"
struct polygon {

    vec3 points[3];
    vec3 delta[3];
    bool skip = false;

    polygon(const vec3 &v1, const vec3 &v2, const vec3 &v3)
        : points{v1, v2, v3} {}
    polygon() : points{} {}

    void calcDelta() {

        for (int i = 0; i < 3; i++) {
            int n = (i + 1) % 3;

            vec3 d = points[n] - points[i];
            delta[i] = vec3(d.y(), -d.x(), d.z());
            if (delta[i].isSmall()) {
                skip = true;
                return;
            }
        }
    }

    bool contains(const vec3 &p) {
        if (skip)
            return false;
        for (int i = 0; i < 3; i++) {
            int n = (i + 1) % 3;

            vec3 s = p - points[n];
            if (s.isSmall())
                return false;
            if (s * delta[i] <= decimal(0.0))
                return false;
        }
        return true;
    }
    friend std::ostream &operator<<(std::ostream &os, const polygon &p) {
        for (int i = 0; i < 3; i++) {
            os << p.points[i];
        }
        return os;
    }
};

#endif