根据时间步进级别调整时间，解决每月每年时间不固定的问题

XCode/Shards/TimeShardPolicy.cs

@@ -1,5 +1,6 @@
 using NewLife;
 using XCode.Configuration;
+using XCode.Statistics;
 
 namespace XCode.Shards;
 
@@ -22,6 +23,9 @@ public class TimeShardPolicy : IShardPolicy
     /// <summary>时间区间步进。遇到时间区间需要扫描多张表时的时间步进，默认1天</summary>
     public TimeSpan Step { get; set; } = TimeSpan.FromDays(1);
 
+    /// <summary>日期级别。年月日</summary>
+    public StatLevels Level { get; set; }
+
     private readonly String? _fieldName;
     #endregion
 
@@ -227,14 +231,29 @@ private ShardModel[] GetModels(DateTime start, DateTime end)
     {
         var models = new List<ShardModel>();
 
+        // 猜测时间步进级别
+        var st = Step;
+        var level = Level;
+        if (level <= 0)
+        {
+            if (st.TotalDays >= 360)
+                level = StatLevels.Year;
+            else if (st.TotalDays >= 28 && st.TotalDays <= 31)
+                level = StatLevels.Month;
+            else if (st.TotalDays == 1)
+                level = StatLevels.Day;
+            else if (st.TotalHours == 1)
+                level = StatLevels.Hour;
+        }
+
         // 根据不仅，把start调整到整点
-        if (Step.TotalDays >= 1)
+        if (st.TotalDays >= 1)
             start = start.Date;
         else if (start.Hour >= 1)
             start = start.Date.AddHours(start.Hour);
 
         var hash = new HashSet<String>();
-        for (var dt = start; dt < end; dt = dt.Add(Step))
+        for (var dt = start; dt < end;)
         {
             var model = Shard(dt);
             if (model != null)
@@ -246,6 +265,18 @@ private ShardModel[] GetModels(DateTime start, DateTime end)
                     hash.Add(key);
                 }
             }
+
+            // 根据时间步进级别调整时间，解决每月每年时间不固定的问题
+            if (level == StatLevels.Year)
+                dt = dt.AddYears(1);
+            else if (level == StatLevels.Month)
+                dt = dt.AddMonths(1);
+            else if (level == StatLevels.Day)
+                dt = dt.AddDays(1);
+            else if (level == StatLevels.Hour)
+                dt = dt.AddHours(1);
+            else
+                dt = dt.Add(st);
         }
 
         //// 标准时间区间 start <= @fi < end ，但是要考虑到end有一部分落入新的分片，减一秒判断