package com.artfess.manage.utils;

import cn.hutool.json.JSONArray;
import cn.hutool.json.JSONUtil;
import com.artfess.base.util.StringUtil;

import java.util.ArrayList;
import java.util.List;

public class GeoUtils {
    static class Point {
        float x;
        float y;

        Point() {
        }

        Point(float x, float y) {
            this.x = x;
            this.y = y;
        }
    }


    public static boolean pointInPolygon(String p, String polyStr) {
        if (StringUtil.isEmpty(polyStr)) {
            return false;
        }
        List<Point> polys = new ArrayList<Point>();
        JSONUtil.parseArray(polyStr).forEach(e -> {
            JSONArray pt = (JSONArray) e;
            polys.add(new Point(Float.valueOf(pt.get(0) + ""), Float.valueOf(pt.get(1) + "")));
        });
        String[] point = p.split(",");
        return ray(new Point(Float.valueOf(point[0] + ""), Float.valueOf(point[1] + "")), polys);
    }

    public static boolean ray(Point p, List<Point> poly) {
        float nx = p.x;
        float ny = p.y;

        int cnt = 0; //计算射线穿过多边形的点的数目

        int len = poly.size();
        for (int i = 0, j = len - 1; i < len; j = i, ++i) {
            float bx = poly.get(i).x;
            float by = poly.get(i).y;
            float ux = poly.get(j).x;
            float uy = poly.get(j).y;

            //点与多边形顶点重合
            if ((nx == bx && ny == by) || (nx == ux && nx == uy)) {
                return true;
            }

            if ((by < ny && uy >= ny) || (by >= ny && uy < ny)) {
                //边上与点的坐标y相同的x坐标
                float x = bx + (ny - by) * (ux - bx) / (uy - by);

                //点在多边形的边上
                if (x == nx) {
                    return true;
                }

                if (x > nx) {
                    cnt += 1;
                }
            }
        }
        if (cnt % 2 == 1) {
            return true;
        } else {
            return false;
        }
    }

}