using GpsCardGatewayPosition.Model.GatewayEntity;
using System;
using System.Collections.Generic;

using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GpsCardGatewayPosition.Common
{
    public class GeoUtils
    {
        private const decimal A = 6370996.81m;

        private const double EARTH_RADIUS = 6378137;//赤道半径(单位m)

        /// <summary>
        /// 点是否在矩形区域中
        /// </summary>
        /// <param name="pt"></param>
        /// <param name="rect"></param>
        /// <returns></returns>
        public static bool IsPointInRect(Point pt, Bounds rect)
        {
            var e = rect.SW;
            var h = rect.NE;
            return (pt.Lng >= e.Lng && pt.Lng <= h.Lng && pt.Lat >= e.Lat && pt.Lat <= h.Lat);
        }
        /// <summary>
        /// 点是否在圆形区域中
        /// </summary>
        /// <param name="pt"></param>
        /// <param name="circle"></param>
        /// <returns></returns>
        public static bool IsPointInCircle(Point pt, Circle circle)
        {
            var i = circle.Center;
            var g = circle.Radius;
            var f = GetDistance(pt, i);
            return f <= g;
        }

        /// <summary>
        /// 获取形状的矩形范围
        /// </summary>
        /// <param name="pts"></param>
        /// <returns></returns>
        public static Bounds GetBound(IList<Point> pts)
        {
            if (pts.Count == 0)
                return new Bounds(new Point(0, 0), new Point(0, 0)); ;
            decimal minLat = pts[0].Lat, minLng = pts[0].Lng, maxLat = pts[0].Lat, maxLng = pts[0].Lng;
            foreach (var pt in pts)
            {
                minLat = Math.Min(minLat, pt.Lat);
                minLng = Math.Min(minLng, pt.Lng);
                maxLat = Math.Max(maxLat, pt.Lat);
                maxLng = Math.Max(maxLng, pt.Lng);
            }

            return new Bounds(new Point(minLng, minLat), new Point(maxLng, maxLat));
        }

        /// <summary>
        /// 经纬度测距算法
        /// </summary>
        /// <param name="lon1"></param>
        /// <param name="lat1"></param>
        /// <param name="lon2"></param>
        /// <param name="lat2"></param>
        /// <returns>单位 米</returns>
        public static double GetDistance2(double lon1, double lat1, double lon2, double lat2)
        {
            double radLat1 = rad(lat1);
            double radLat2 = rad(lat2);
            double a = radLat1 - radLat2;
            double b = rad(lon1) - rad(lon2);
            double s = 2 * Math.Asin(Math.Sqrt(Math.Pow(Math.Sin(a / 2), 2) + Math.Cos(radLat1) * Math.Cos(radLat2) * Math.Pow(Math.Sin(b / 2), 2)));
            s = s * EARTH_RADIUS;
            return s;
        }

        /// <summary>
        /// 转化为弧度(rad) 
        /// </summary>
        /// <param name="d">经度或纬度</param>
        /// <returns>弧度</returns>
        private static double rad(double d)
        {
            return d * Math.PI / 180.0;
        }


        /// <summary>
        /// 计算两点的距离 单位：米
        /// </summary>
        /// <param name="j"></param>
        /// <param name="h"></param>
        /// <returns></returns>
        public static decimal GetDistance(Point j, Point h)
        {
            j.Lng = ValidLng(j.Lng, -180, 180);
            j.Lat = ValidLat(j.Lat, -74, 74);
            h.Lng = ValidLng(h.Lng, -180, 180);
            h.Lat = ValidLat(h.Lat, -74, 74);
            decimal f, e, i, g;
            f = DegreeToRad(j.Lng);
            i = DegreeToRad(j.Lat);
            e = DegreeToRad(h.Lng);
            g = DegreeToRad(h.Lat);
            return Convert.ToDecimal((double)A * Math.Acos((Math.Sin((double)i) * Math.Sin((double)g) + Math.Cos((double)i) * Math.Cos((double)g) * Math.Cos((double)e - (double)f))));
        }

        private static decimal DegreeToRad(decimal d)
        {
            return Convert.ToDecimal(Math.PI * (double)d / 180);
        }

        private static decimal RadToDegree(decimal d)
        {
            return Convert.ToDecimal((180 * (double)d) / Math.PI);
        }

        private static decimal ValidLng(decimal lng, decimal min, decimal max)
        {
            while (lng > max)
            {
                lng -= max - min;
            }
            while (lng < min)
            {
                lng += max - min;
            }
            return lng;
        }

        private static decimal ValidLat(decimal lat, decimal min, decimal max)
        {
            lat = Math.Max(lat, min);
            lat = Math.Min(lat, max);
            return lat;
        }
    }
}