#ifndef POLYGON_H
#define POLYGON_H

#include "fastmath.hpp"
struct polygon {

    vec3 points[3];
    decimal delta[9];
    bool small = false;
    decimal baryFactor;

    decimal bounding[4]; // min x, max x, min y, max y
    vec3 normals[3];

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

    void calcDelta() {

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

            delta[i * 3] = points[i].y() - points[n].y();
            delta[i * 3 + 1] = points[n].x() - points[i].x();
            delta[i * 3 + 2] =
                points[i].x() * points[n].y() - points[i].y() * points[n].x();
            if (delta[i * 3].i == 0 && delta[i * 3 + 1].i == 0)
                small = true;
        }
        bounding[0] = points[0].x();
        bounding[1] = points[0].x();
        bounding[2] = points[0].y();
        bounding[3] = points[0].y();
        for (int i = 1; i < 3; i++) {
            if (bounding[0] > points[i].x())
                bounding[0] = points[i].x();
            if (bounding[1] < points[i].x())
                bounding[1] = points[i].x();
            if (bounding[2] > points[i].y())
                bounding[2] = points[i].y();
            if (bounding[3] < points[i].y())
                bounding[3] = points[i].y();
        }

        baryFactor =
            (points[1].x() - points[0].x()) * (points[2].y() - points[1].y()) -
            (points[1].y() - points[0].y()) * (points[2].x() - points[1].x());

        if (baryFactor.isSmall()) {
            small = true;
        } else
            baryFactor = decimal(1.0) / baryFactor;
        // std::cout << baryFactor << std::endl;
        /*if ((bounding[1].i - bounding[0].i < 1 << HALF_SHIFT) &&
            (bounding[3].i - bounding[2].i < 1 << HALF_SHIFT))
            small = true;*/
    }

    const bool contains(const vec3 &p) {
        // if (skip)
        //    return false;
        for (int i = 0; i < 3; i++) {
            if (small)
                return true;
            vec3 d = p;
            if ((d.x() * delta[i * 3] + d.y() * delta[i * 3 + 1] +
                 delta[i * 3 + 2]) > decimal(0.2))
                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;
    }

    vec3 calcNormal(vec3 barycentrics) {
        vec3 result = normals[0] * barycentrics[0] +
                      normals[1] * barycentrics[1] +
                      normals[2] * barycentrics[2];
        return result.normalize();
    }

    decimal calcDepth(vec3 barycentrics) {
        return points[0].z() * barycentrics[0] +
               points[1].z() * barycentrics[1] +
               points[2].z() * barycentrics[2];
    }

    vec3 calcBarycentric(vec3 s) {
        if (small)
            return vec3(decimal(0.333), decimal(0.333), decimal(0.333));
        vec3 result;
        result[0] = (points[1].x() - s.x()) * (points[2].y() - s.y()) -
                    (points[2].x() - s.x()) * (points[1].y() - s.y());
        result[1] = (points[2].x() - s.x()) * (points[0].y() - s.y()) -
                    (points[0].x() - s.x()) * (points[2].y() - s.y());
        result = result * baryFactor;
        result[2] = decimal(1.0) - result[1] - result[0];
        return result;
    }
};

#endif