using Microsoft.CodeAnalysis.CSharp.Syntax;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Admin.NET.Core.Service
{


    /// <summary>
    /// 根据经纬度获取城市
    /// </summary>
    [ApiDescriptionSettings(Order = 101)]
    [AllowAnonymous]
    public class LocationService : IDynamicApiController, ITransient
    {
        private readonly SqlSugarRepository<SysRegion> _region;
        public LocationService(SqlSugarRepository<SysRegion> reginService)
        {

            this._region = reginService;
        }

        /// <summary>
        /// Haversine公式计算距离
        /// </summary>
        /// <param name="lat1"></param>
        /// <param name="lon1"></param>
        /// <param name="lat2"></param>
        /// <param name="lon2"></param>
        /// <returns></returns>
        private double CalculateDistance(double lat1, double lon1, double lat2, double lon2)
        {
            const double R = 6371; // 地球半径，单位：千米
            double dLat = (lat2 - lat1) * (Math.PI / 180);
            double dLon = (lon2 - lon1) * (Math.PI / 180);
            double a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2) +
                       Math.Cos(lat1 * (Math.PI / 180)) * Math.Cos(lat2 * (Math.PI / 180)) *
                       Math.Sin(dLon / 2) * Math.Sin(dLon / 2);
            double c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
            return R * c;
        }


        // 根据传入的经纬度查找最近的城市
        [NonAction]
        private CityData FindNearestCity(List<CityData> _cityDataList, double targetLatitude, double targetLongitude)
        {
            if (_cityDataList.Count == 0)
            {
                return new CityData() { };
            }

            double minDistance = double.MaxValue;
            var nearestCity = new CityData();

            foreach (var cityData in _cityDataList)
            {
                double distance = CalculateDistance(targetLatitude, targetLongitude, cityData.Latitude, cityData.Longitude);
                if (distance < minDistance)
                {
                    minDistance = distance;
                    nearestCity = cityData;
                }
            }

            return nearestCity;
        }


        /// <summary>
        /// 根据经纬度获取城市
        /// </summary>
        /// <param name="lng"></param>
        /// <param name="lat"></param>
        /// <returns></returns>
        [HttpGet("getcity")]
        public dynamic GetCity([FromQuery] double lng, [FromQuery] double lat)
        {
            var citylist = this._region.AsQueryable().Where(e => e.Level == 1).ToList();

            List<CityData> cities = citylist.Select(s => new CityData()
            {
                Latitude = s.Lat,
                Longitude = s.Lng,
                CityName = s.Name,
                LocationCode = s.Code
            }).ToList();
            return FindNearestCity(cities, lat, lng);

        }




      



    }

}