refactor: do not render chart if no commit collected in statistics

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/Models/Statistics.cs

@@ -42,11 +42,14 @@ public StatisticsSamples(StatisticsMode mode, DateTime start, DateTime end, Dict
             else
                 MaxValue = (int)(Math.Floor(maxValue / 6.0) * 8.0);
 
-            Count = mode switch
-            {
-                StatisticsMode.All => (end.Year - start.Year) * 12 + (end.Month - start.Month) + 1,
-                _ => all.Count,
-            };
+            if (maxValue == 0)
+                Count = 0;
+            else
+                Count = mode switch
+                {
+                    StatisticsMode.All => (end.Year - start.Year) * 12 + (end.Month - start.Month) + 1,
+                    _ => all.Count,
+                };
         }
 
         public void WithUser(Dictionary<DateTime, int> user)

src/Views/Chart.cs

@@ -54,7 +54,7 @@ public override void Render(DrawingContext context)
             base.Render(context);
 
             var samples = _samples;
-            if (samples == null || samples.Count <= 0)
+            if (samples == null || samples.Count == 0)
                 return;
 
             var w = Bounds.Width;