using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace GPSServer.Helper
{
    public class CalculationGpsHelper
    {
        /// <summary>    
        /// 地球的半径    
        /// </summary>    
        private const double EarthRadius = 6378137.0;//地球半径(米)
        /// <summary>
        /// 角度数转换为弧度公式
        /// </summary>
        /// <param name="d"></param>
        /// <returns></returns>
        private static double Radians(double d)
        {
            return d * Math.PI / 180.0;
        }
        /// <summary>
        /// 弧度转换为角度数公式
        /// </summary>
        /// <param name="d"></param>
        /// <returns></returns>
        private static double Degrees(double d)
        {
            return d * (180 / Math.PI);
        }
        // 计算2个经纬度距离
        public static int GetDistance(double lng1, double lat1, double lng2, double lat2)
        {
            //最东端 东经135度2分30秒 黑龙江和乌苏里江交汇处 
            //最西端 东经73度40分 帕米尔高原乌兹别里山口（乌恰县） 
            //最南端 北纬3度52分 南沙群岛曾母暗沙 
            //最北端 北纬53度33分 漠河以北黑龙江主航道（漠河)
            try
            {
                if (lng1 > 73 && lat1 > 3 && lng2 > 73 && lat2 > 3)
                {
                    decimal proDecimal = (decimal)CalculationDistance(lng1, lat1, lng2, lat2);
                    return Convert.ToInt32(proDecimal);
                }
                return 0;
            }
            catch (Exception)
            {
                return 0;
            }
        }
        /// <summary>    
        /// 计算坐标点的距离    
        /// </summary>    
        /// <param name="long1">开始的经度</param>    
        /// <param name="lat1">开始的纬度</param>    
        /// <param name="long2">结束的经度</param>    
        /// <param name="lat2">结束的纬度</param>    
        /// <returns>距离(米)</returns>    
        public static double CalculationDistance(double long1, double lat1, double long2, double lat2)
        {
            double a, b, R;
            R = EarthRadius; //地球半径
            lat1 = Radians(lat1);
            lat2 = Radians(lat2);
            a = lat1 - lat2;
            b = Radians(long1-long2);
            double d, sa2, sb2;
            sa2 = Math.Sin(a / 2.0);
            sb2 = Math.Sin(b / 2.0);
            d = 2 * R * Math.Asin(Math.Sqrt(sa2 * sa2 + Math.Cos(lat1) * Math.Cos(lat2) * sb2 * sb2));
            return d;
        }


        /// <summary>
        /// 时间差格式转换
        /// </summary>
        /// <param name="ts">时间差</param>
        /// <param name="Accuracy">精确度，默认为2</param>
        /// <returns></returns>
        public static string TimeSpanFormat(TimeSpan ts, int Accuracy = 2)
        {
            StringBuilder sb = new StringBuilder();
            int idx = 0;
            if (ts.Days != 0 && idx < Accuracy)
            {
                sb.Append(ts.Days + "天");
                idx++;
            }
            if (ts.Hours != 0 && idx < Accuracy)
            {
                sb.Append(ts.Hours + "小时");
                idx++;
            }
            if (ts.Minutes != 0 && idx < Accuracy)
            {
                sb.Append(ts.Minutes + "分");
                idx++;
            }
            if (ts.Seconds != 0 && idx < Accuracy)
            {
                sb.Append(ts.Seconds + "秒");
            }
            if (ts.Days == 0 && ts.Hours == 0 && ts.Minutes == 0 && ts.Seconds == 0)
            {
                sb.Append("0秒");
            }
            return sb.ToString();
        }
    }
}