add more safety and a couple tests

ErsatzTV.Core.Tests/Scheduling/AlternateScheduleSelectorTests.cs

@@ -863,5 +863,53 @@ public static class AlternateScheduleSelectorTests
 
             result.IsNone.ShouldBeFalse();
         }
+
+        [Test]
+        public void LimitToDateRange_13th_Month_Should_Not_Crash()
+        {
+            var template = new PlayoutTemplate
+            {
+                DaysOfWeek = AlternateScheduleSelector.AllDaysOfWeek(),
+                DaysOfMonth = AlternateScheduleSelector.AllDaysOfMonth(),
+                MonthsOfYear = AlternateScheduleSelector.AllMonthsOfYear(),
+                LimitToDateRange = true,
+                StartMonth = 13,
+                StartDay = 30,
+                StartYear = 2022,
+                EndMonth = 13,
+                EndDay = 30,
+                EndYear = 2023
+            };
+
+            Option<PlayoutTemplate> result = AlternateScheduleSelector.GetScheduleForDate(
+                new List<PlayoutTemplate> { template },
+                new DateTimeOffset(2023, 3, 1, 0, 0, 0, Offset));
+
+            result.IsNone.ShouldBeTrue();
+        }
+
+        [Test]
+        public void LimitToDateRange_0th_Day_Should_Not_Crash()
+        {
+            var template = new PlayoutTemplate
+            {
+                DaysOfWeek = AlternateScheduleSelector.AllDaysOfWeek(),
+                DaysOfMonth = AlternateScheduleSelector.AllDaysOfMonth(),
+                MonthsOfYear = AlternateScheduleSelector.AllMonthsOfYear(),
+                LimitToDateRange = true,
+                StartMonth = 12,
+                StartDay = 0,
+                StartYear = 2022,
+                EndMonth = 12,
+                EndDay = 0,
+                EndYear = 2023
+            };
+
+            Option<PlayoutTemplate> result = AlternateScheduleSelector.GetScheduleForDate(
+                new List<PlayoutTemplate> { template },
+                new DateTimeOffset(2023, 3, 1, 0, 0, 0, Offset));
+
+            result.IsNone.ShouldBeTrue();
+        }
     }
 }

ErsatzTV.Core/Scheduling/AlternateScheduleSelector.cs

@@ -26,6 +26,12 @@ public static class AlternateScheduleSelector
         {
             if (item.LimitToDateRange)
             {
+                if (item.StartMonth is < 1 or > 12 || item.EndMonth is < 1 or > 12 || item.StartDay < 1 ||
+                    item.EndDay < 1)
+                {
+                    continue;
+                }
+
                 bool reverse = item.StartMonth * 100 + item.StartDay >
                                item.EndMonth * 100 + item.EndDay;
 

ErsatzTV.Core/Scheduling/YamlScheduling/Models/YamlPlayoutScheduleItem.cs

@@ -23,13 +23,13 @@ public class YamlPlayoutScheduleItem : IAlternateScheduleItem
 
     // schedules are purely date-range based, so every day/month is eligible
     [YamlIgnore]
-    public ICollection<DayOfWeek> DaysOfWeek => Enum.GetValues<DayOfWeek>();
+    public ICollection<DayOfWeek> DaysOfWeek => AlternateScheduleSelector.AllDaysOfWeek();
 
     [YamlIgnore]
-    public ICollection<int> DaysOfMonth => Enumerable.Range(1, 31).ToList();
+    public ICollection<int> DaysOfMonth => AlternateScheduleSelector.AllDaysOfMonth();
 
     [YamlIgnore]
-    public ICollection<int> MonthsOfYear => Enumerable.Range(1, 12).ToList();
+    public ICollection<int> MonthsOfYear => AlternateScheduleSelector.AllMonthsOfYear();
 
     [YamlIgnore]
     public bool LimitToDateRange => true;