using WorkerService1.Domains;

namespace WorkerService1.Utils;

public static class Utilities
{
    public static bool IsPointInsidePolygon(this Points point, Polygon polygon)
    {
        // 使用射线交叉法判断点是否在多边形内  
        int count = 0;
        double x0 = point.X;
        double y0 = point.Y;
        for (int i = 0; i < polygon.Points.Count; i++)
        {
            var currentPolygon = polygon.Points[i];
            for (int i2 = 0; i2 < currentPolygon.Count; i2++)
            {
                int next = (i2 + 1) % currentPolygon.Count;
                int prev = (i2 - 1 + currentPolygon.Count) % currentPolygon.Count;
                double x1 = currentPolygon[next].X;
                double y1 = currentPolygon[next].Y;
                double x2 = currentPolygon[prev].X;
                double y2 = currentPolygon[prev].Y;
                if (((y1 > y0) && (y2 <= y0)) || ((y2 > y0) && (y1 <= y0)))
                {
                    double intersection = (x1 - x2) * (y0 - y2) / (y1 - y2) + x2;
                    if (x0 < intersection)
                    {
                        count++;
                    }
                }
            }

            if (count % 2 == 1) return true;
        }

        return false;
    }
}