using System;
using GpsModels;

namespace GPSBusiness.Helper
{
    //===高德谷歌使用：火星坐标系 (GCJ-02)===百度使用：(BD-09)坐标系为前者的加密===
    //===部标Gps一般采用：WGS84坐标系。
    public static class ConvertGps
    {
        private static double pi = 3.1415926535897932384626;
        private static double a = 6378245.0;
        private static double ee = 0.00669342162296594323;
        private static double bd_pi = 3.14159265358979324 * 3000.0 / 180.0;
        static Boolean OutOfChina(double lat, double lon)
        {
            if (lon < 72.004 || lon > 137.8347)
                return true;
            if (lat < 0.8293 || lat > 55.8271)
                return true;
            return false;
        }
        static double TransformLat(double x, double y)
        {
            double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y
                         + 0.2 * Math.Sqrt(Math.Abs(x));
            ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
            ret += (20.0 * Math.Sin(y * pi) + 40.0 * Math.Sin(y / 3.0 * pi)) * 2.0 / 3.0;
            ret += (160.0 * Math.Sin(y / 12.0 * pi) + 320 * Math.Sin(y * pi / 30.0)) * 2.0 / 3.0;
            return ret;
        }
        static double TransformLon(double x, double y)
        {
            double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1
                         * Math.Sqrt(Math.Abs(x));
            ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
            ret += (20.0 * Math.Sin(x * pi) + 40.0 * Math.Sin(x / 3.0 * pi)) * 2.0 / 3.0;
            ret += (150.0 * Math.Sin(x / 12.0 * pi) + 300.0 * Math.Sin(x / 30.0
                                                               * pi)) * 2.0 / 3.0;
            return ret;
        }

        // 【84】-->【GCJ-02】
        public static PointLatLng Gps84ToGcj02(PointLatLng gpoint)
        {
            if (OutOfChina(gpoint.Lat, gpoint.Lng))
            {
                return new PointLatLng(0, 0);
            }
            double dLat = TransformLat(gpoint.Lng - 105.0, gpoint.Lat - 35.0);
            double dLon = TransformLon(gpoint.Lng - 105.0, gpoint.Lat - 35.0);
            double radLat = gpoint.Lat / 180.0 * pi;
            double magic = Math.Sin(radLat);
            magic = 1 - ee * magic * magic;
            double sqrtMagic = Math.Sqrt(magic);
            dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
            dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
            double mgLat = gpoint.Lat + dLat;
            double mgLon = gpoint.Lng + dLon;
            return new PointLatLng(mgLat, mgLon);
        }

        // 【GCJ-02】-->【84】 
        public static PointLatLng Gcj02ToGps84(PointLatLng gpoint)
        {
            PointLatLng gps = Transform(gpoint);
            double lontitude = gpoint.Lng * 2 - gps.Lng;
            double latitude = gpoint.Lat * 2 - gps.Lat;
            return new PointLatLng(latitude, lontitude);
        }

        // 【GCJ-02】-->【BD-09】
        public static PointLatLng Gcj02ToBd09(PointLatLng gpoint)
        {
            double x = gpoint.Lng, y = gpoint.Lat;
            double z = Math.Sqrt(x * x + y * y) + 0.00002 * Math.Sin(y * bd_pi);
            double theta = Math.Atan2(y, x) + 0.000003 * Math.Cos(x * bd_pi);
            double bd_lon = z * Math.Cos(theta) + 0.0065;
            double bd_lat = z * Math.Sin(theta) + 0.006;
            return new PointLatLng(bd_lat, bd_lon);
        }

        // 【BD-09】-->【GCJ-02】
        public static PointLatLng Bd09ToGcj02(PointLatLng bdPoint)
        {
            double x = bdPoint.Lng - 0.0065, y = bdPoint.Lat - 0.006;
            double z = Math.Sqrt(x * x + y * y) - 0.00002 * Math.Sin(y * bd_pi);
            double theta = Math.Atan2(y, x) - 0.000003 * Math.Cos(x * bd_pi);
            double gg_lon = z * Math.Cos(theta);
            double gg_lat = z * Math.Sin(theta);
            return new PointLatLng(gg_lat, gg_lon);
        }

        // 【BD-09】-->【84】 
        public static PointLatLng Bd09ToGps84(PointLatLng bdPoint)
        {
            PointLatLng gcj02 = Bd09ToGcj02(bdPoint);
            PointLatLng map84 = Gcj02ToGps84(gcj02);
            //保留小数点后六位  
            //map84.Lat = Retain6(map84.Lat);
            //map84.Lng = Retain6(map84.Lng);
            return map84;
        }

        //【84】-->【BD-09】
        public static PointLatLng Gps84ToBd09(PointLatLng gpsPoint)
        {
            PointLatLng gcj02 = Gps84ToGcj02(gpsPoint);
            PointLatLng bd09 = Gcj02ToBd09(gcj02);
            return bd09;
        }

        static PointLatLng Transform(PointLatLng gpoint)
        {
            if (OutOfChina(gpoint.Lat, gpoint.Lng))
            {
                return new PointLatLng(gpoint.Lat, gpoint.Lng);
            }
            double dLat = TransformLat(gpoint.Lng - 105.0, gpoint.Lat - 35.0);
            double dLon = TransformLon(gpoint.Lng - 105.0, gpoint.Lat - 35.0);
            double radLat = gpoint.Lat / 180.0 * pi;
            double magic = Math.Sin(radLat);
            magic = 1 - ee * magic * magic;
            double sqrtMagic = Math.Sqrt(magic);
            dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
            dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
            double mgLat = gpoint.Lat + dLat;
            double mgLon = gpoint.Lng + dLon;
            return new PointLatLng(mgLat, mgLon);
        }

        /// <summary>
        /// 保留小数点后六位 
        /// </summary>
        /// <param name="num"></param>
        /// <returns></returns>
        private static double Retain6(double num)
        {
            String result = String.Format("%.6f", num);
            return Double.Parse(result);
        }
    }
}