using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using XdCxRhDW.Repostory.EFContext;
using XdCxRhDW.Repostory.Model;

namespace XdCxRhDW.Repostory
{
    public static class XlCache
    {
        /// <summary>
        /// 获取数据库所有双行根数
        /// </summary>
        /// <param name="maxCount">最大条数.超过此条数时不再继续查询,为0则不限制条数</param>
        /// <returns></returns>
        public static async Task<List<XlInfo>> GetAllAsync(int maxCount = 2000)
        {
            try
            {
                List<XlInfo> list = new List<XlInfo>();
                var dir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "DbPart");
                if (!Directory.Exists(dir)) return list;
                var yearDirs = Directory.EnumerateDirectories(dir).OrderByDescending(p => Convert.ToInt32(new DirectoryInfo(p).Name));//年目录,倒叙排列
                foreach (var yearDir in yearDirs)
                {
                    //每一天的db文件,倒序排列
                    var dayFiles = Directory.EnumerateFiles(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, yearDir), "*.db").OrderByDescending(p => Convert.ToInt32(new DirectoryInfo(p).Name.Substring(0, 4)));
                    foreach (var dayFile in dayFiles)
                    {
                        using (RHDWPartContext db = RHDWPartContext.GetContext(dayFile))
                        {
                            list.AddRange(await db.XlInfos.ToListAsync());
                            if (maxCount > 0 && list.Count >= maxCount)
                                return list;
                        }
                    }
                }
                return list;
            }
            catch (Exception ex)
            {
                Serilog.Log.Error(ex, "加载星历信息异常");
                return null;
            }
        }


        /// <summary>
        /// 获取某个星某个时刻最近的双行根(可能返回null)
        /// </summary>
        /// <param name="satCode">卫星编号</param>
        /// <param name="timeBj">时刻</param>
        /// <returns></returns>
        public static async Task<XlInfo> GetLatestAsync(int satCode, DateTime timeBj)
        {
            try
            {

                var list = await GetAllAsync(0);
                if (!list.Any()) return null;
                var mainXl = list.Where(w => w.SatCode == satCode);
                var minSec = mainXl.Min(p => Math.Abs((p.TimeBJ - timeBj).TotalSeconds));
                var find = mainXl.FirstOrDefault(p => Math.Abs((p.TimeBJ - timeBj).TotalSeconds) == minSec);
                return find;
            }
            catch (Exception ex)
            {
                Serilog.Log.Error(ex, $"获取卫星[{satCode}]--{timeBj:yyyyMMddHHmmss}时刻附近的双行根数出错!");
                return null;
            }
        }
    }
}