fix: remove already-played playout items

CHANGELOG.md

@@ -24,6 +24,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - More rarely, content with an embedded subtitle that has stream index zero would create invalid subtitle records
   - Both cases will automatically be cleaned up during the next local library scan
 - Use `und` language tag with sidecar subtitles that have no language in the file name
+- Automatically remove already-played playout items from all on demand channels
+- Automatically remove already-played playout items from (continuous) scripted schedules
 
 ### Changed
 - Upgrade Intel driver in docker containers to support latest Battlemage devices (e.g. B70)

ErsatzTV.Core/Scheduling/PlayoutBuilder.cs

@@ -301,6 +301,7 @@ public class PlayoutBuilder : IPlayoutBuilder
         playout.Seed = new Random().Next();
 
         // don't trim start for on demand channels, we want to time shift it all forward
+        // on-demand channels will trim already-played items in time shifter
         if (referenceData.Channel.PlayoutMode is ChannelPlayoutMode.OnDemand)
         {
             TrimStart = false;

ErsatzTV.Core/Scheduling/ScriptedScheduling/ScriptedPlayoutBuilder.cs

@@ -108,6 +108,12 @@ public class ScriptedPlayoutBuilder(
 
             playout.Anchor = schedulingEngine.GetAnchor();
 
+            // on-demand channels will trim already-played items in time shifter
+            if (referenceData.Channel.PlayoutMode != ChannelPlayoutMode.OnDemand)
+            {
+                schedulingEngine.RemoveBefore(start.AddHours(-4));
+            }
+
             result = MergeResult(result, schedulingEngine.GetState());
         }
         catch (OperationCanceledException)

ErsatzTV.Infrastructure/Scheduling/PlayoutTimeShifter.cs

@@ -72,6 +72,21 @@ public class PlayoutTimeShifter(
                     playout.OnDemandCheckpoint = playout.Items.Min(p => p.StartOffset);
                 }
 
+                // remove items that have finished before the checkpoint
+                foreach (DateTimeOffset checkpoint in Optional(playout.OnDemandCheckpoint))
+                {
+                    DateTime checkpointUtc = checkpoint.UtcDateTime;
+                    int removed = playout.Items.RemoveAll(i => i.Finish < checkpointUtc);
+                    if (removed > 0)
+                    {
+                        logger.LogDebug(
+                            "Removing {Count} played items before shifting playout for channel {Number} - {Name}",
+                            removed,
+                            playout.Channel.Number,
+                            playout.Channel.Name);
+                    }
+                }
+
                 TimeSpan toOffset = now - playout.OnDemandCheckpoint.IfNone(now);
 
                 logger.LogDebug(