DW5S/DW5S.Repostory/Repository/XlRepository.cs

using DW5S.Entity;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DW5S.Repostory
{
    /// <summary>
    /// 双行根星历仓储
    /// </summary>
    public class XlRepository : Repository<XlInfo>
    {
        public XlRepository(OracleContext ctx)
            : base(ctx)
        {
        }

        /// <summary>
        /// 获取双行根数总条数
        /// </summary>
        /// <param name="satCode"></param>
        /// <returns></returns>
        public async Task<int> GetCount(int? satCode)
        {
            var queryable = base.dbSet.AsQueryable();
            if (satCode != null)
                queryable = queryable.Where(p => p.SatCode == satCode);
            var count = await queryable.CountAsync();
            return count;
        }

        /// <summary>
        /// 获取数据库双行根数
        /// </summary>
        /// <param name="currentPage">当前页(从1开始)</param>
        /// <param name="pageSize">每页显示的条数</param>
        /// <param name="satCode">卫星编号</param>
        /// <returns></returns>
        public async Task<List<XlInfo>> GetPageAsync(int currentPage, int pageSize, int? satCode)
        {
            try
            {
                int skip = (currentPage - 1) * pageSize;
                var queryable = base.dbSet.AsQueryable();
                if (satCode != null)
                    queryable = queryable.Where(p => p.SatCode == satCode);
                var res = await queryable.OrderByDescending(p => p.TimeUTC)
                    .ThenByDescending(p => p.Lon).Skip(skip).Take(pageSize).ToListAsync();
                return res;
            }
            catch (Exception ex)
            {
                throw new Exception("分页星历信息查询异常", ex);
            }
        }

        /// <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="sigTime">时刻</param>
        /// <returns></returns>
        public async Task<XlInfo> GetLatestAsync(int satCode, DateTime sigTime)
        {
            try
            {
                var max =await dbSet.Where(p => p.SatCode == satCode && p.TimeUTC >= sigTime)
                    .OrderBy(p => p.TimeUTC).FirstOrDefaultAsync();
                var min =await dbSet.Where(p => p.SatCode == satCode && p.TimeUTC <= sigTime)
                    .OrderByDescending(p => p.TimeUTC).FirstOrDefaultAsync();

                if (max == null && min == null)
                    return null;
                else if (max != null && min == null)
                    return max;
                else if (max == null && min != null)
                    return min;
                else
                {
                    //谁离得更接近就用谁
                    var val1 = Math.Abs((max.TimeUTC - sigTime).TotalSeconds);
                    var val2 = Math.Abs((min.TimeUTC - sigTime).TotalSeconds);
                    if (val1 < val2)
                        return max;
                    else
                        return min;
                }
            }
            catch (Exception ex)
            {
                throw new Exception($"获取卫星[{satCode}]--{sigTime:yyyyMMddHHmmss}时刻附近的双行根数出错!", ex);
            }
        }
    }
}