/*------------------------------------------------------------------------------
 *	Copyright (c) 2023 by Bai Bing (seread@163.com)
 *	See COPYING file for copying and redistribution conditions.
 *
 *  Alians IT Studio.
 *----------------------------------------------------------------------------*/
#pragma once

#include "_Define.h"
#include "utils/EssentiallyEqual.h"

#include "ASPoint.h"

namespace ais
{
    template <typename PT = ais::Point>
    inline int cross(const PT &a, const PT &b, const PT &c)
    {
        return ais::dcmp((b.x - a.x) * (c.y - a.y) - (c.x - a.x) * (b.y - a.y));
    }

    template <typename PT = ais::Point>
    inline bool line_cross(const PT &p1, const PT &p2, const PT &q1, const PT &q2)
    {
        if (std::max(p1.x, p2.x) >= std::min(q1.x, q2.x) &&
            std::max(q1.x, q2.x) >= std::min(p1.x, p2.x) &&
            std::max(p1.y, p2.y) >= std::min(q1.y, q2.y) &&
            std::max(q1.y, q2.y) >= std::min(p1.y, p2.y))
        {
            if (cross(p1, p2, q1) * cross(p1, p2, q2) <= 0 && cross(q1, q2, p1) * cross(q1, q2, p2) <= 0)
            {
                return true;
            }
        }

        return false;
    }

    template <typename PT = ais::Point>
    inline bool line_intersect(const std::vector<PT> &line, const std::vector<PT> &polygon)
    {
        for (auto &p : line)
        {
            if (p.in_polygon(polygon))
                return true;
        }

        size_t n = polygon.size();
        for (auto i = 0; i != n; i++)
            if (line_cross(line[0], line[1], polygon[i], polygon[((i + 1) % n)]))
                return true;

        return false;
    }

    template <typename PT = ais::Point>
    bool polygon_intersect(const std::vector<PT> &p1, const std::vector<PT> &p2)
    {
        for (auto &p : p1)
        {
            if (p.in_polygon(p2))
                return true;
        }

        for (auto &p : p2)
        {
            if (p.in_polygon(p1))
                return true;
        }

        size_t n = p1.size();
        size_t m = p2.size();

        for (auto i = 0; i != n; i++)
            for (auto j = 0; j != m; j++)
                if (line_cross(p1[i], p1[((i + 1) % n)], p2[j], p2[((j + 1) % m)]))
                    return true;

        return false;
    }
}