fix scripted schedule building across offsets (#2569)

CHANGELOG.md

@@ -56,6 +56,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Fix playout builder getting stuck (forever) on block item with an empty collection
 - Fix HLS Direct playback when using custom stream selector or preferred audio language/title
 - Fix selecting embedded subtitles (text and picture) with HLS Direct
+- Fix building scripted schedules across a UTC offset change
 
 ### Changed
 - Do not use graphics engine for single, permanent watermark

ErsatzTV.Core.Tests/Scheduling/Engine/SchedulingEngineTests.cs

@@ -0,0 +1,35 @@
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Repositories;
+using ErsatzTV.Core.Scheduling.Engine;
+using Microsoft.Extensions.Logging;
+using NSubstitute;
+using NUnit.Framework;
+
+namespace ErsatzTV.Core.Tests.Scheduling.Engine;
+
+[TestFixture]
+public class SchedulingEngineTests
+{
+    [Test]
+    public void Continue_Across_Time_Change()
+    {
+        var engine = new SchedulingEngine(
+            Substitute.For<IMediaCollectionRepository>(),
+            Substitute.For<IGraphicsElementRepository>(),
+            Substitute.For<IChannelRepository>(),
+            Substitute.For<ILogger<SchedulingEngine>>());
+
+        var anchor = new PlayoutAnchor
+        {
+            NextStart = new DateTimeOffset(new DateTime(2025, 10, 26), TimeSpan.FromHours(-5)).UtcDateTime
+        };
+
+        var start = new DateTimeOffset(new DateTime(2025, 11, 20), TimeSpan.FromHours(-6));
+        var finish = start.AddDays(1);
+
+        engine.BuildBetween(start, finish);
+
+        // should not throw
+        engine.RestoreOrReset(anchor);
+    }
+}

ErsatzTV.Core/Scheduling/Engine/SchedulingEngine.cs

@@ -92,7 +92,7 @@ public class SchedulingEngine(
         {
             foreach (PlayoutAnchor anchor in maybeAnchor)
             {
-                _state.CurrentTime = new DateTimeOffset(anchor.NextStart.ToLocalTime(), _state.CurrentTime.Offset);
+                _state.CurrentTime = new DateTimeOffset(anchor.NextStart, TimeSpan.Zero).ToLocalTime();
 
                 if (string.IsNullOrWhiteSpace(anchor.Context))
                 {