fix: randomize start points with classic playlists

CHANGELOG.md

@@ -8,6 +8,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Update Plex movie and other video titles when changed from Plex
   - The first library scan after updating will act like a deep scan due to adding title to the Plex etag calculation
   - Future periodic scans will update titles in ETV automatically (deep scans will not be required to update titles)
+- Randomize start points on playlist items in classic schedules when setting is enabled
+  - Playlists ignored this setting in earlier builds
 
 ## [26.6.0] - 2026-07-09
 ### Added

ErsatzTV.Core.Tests/Scheduling/PlaylistEnumeratorTests.cs

@@ -62,6 +62,7 @@ public class PlaylistEnumeratorTests
             new CollectionEnumeratorState(),
             shufflePlaylistItems: false,
             batchSize: Option<int>.None,
+            randomStartPoint: false,
             CancellationToken.None);
 
         var items = new List<int>();
@@ -130,6 +131,7 @@ public class PlaylistEnumeratorTests
             new CollectionEnumeratorState(),
             shufflePlaylistItems: false,
             batchSize: Option<int>.None,
+            randomStartPoint: false,
             CancellationToken.None);
 
         var items = new List<int>();
@@ -200,6 +202,7 @@ public class PlaylistEnumeratorTests
             state,
             shufflePlaylistItems: true,
             batchSize: Option<int>.None,
+            randomStartPoint: false,
             CancellationToken.None);
 
         var items = new List<int>();
@@ -270,6 +273,7 @@ public class PlaylistEnumeratorTests
             state,
             shufflePlaylistItems: true,
             batchSize: Option<int>.None,
+            randomStartPoint: false,
             CancellationToken.None);
 
         var items = new List<int>();
@@ -352,6 +356,7 @@ public class PlaylistEnumeratorTests
             state,
             shufflePlaylistItems: true,
             batchSize: Option<int>.None,
+            randomStartPoint: false,
             CancellationToken.None);
 
         enumerator.CountForFiller.ShouldBe(7);

ErsatzTV.Core/Scheduling/BlockScheduling/BlockPlayoutEnumerator.cs

@@ -168,6 +168,7 @@ public static class BlockPlayoutEnumerator
             state,
             shufflePlaylistItems: false,
             batchSize: Option<int>.None,
+            randomStartPoint: false,
             cancellationToken);
 
         DateTime historyTime = currentTime.UtcDateTime;

ErsatzTV.Core/Scheduling/Engine/MarathonHelper.cs

@@ -66,6 +66,7 @@ public class MarathonHelper(IMediaCollectionRepository mediaCollectionRepository
             state,
             marathonShuffleGroups,
             marathonBatchSize,
+            randomStartPoint: false,
             cancellationToken);
     }
 
@@ -136,6 +137,7 @@ public class MarathonHelper(IMediaCollectionRepository mediaCollectionRepository
             state,
             shuffleGroups,
             batchSize: Option<int>.None,
+            randomStartPoint: false,
             cancellationToken);
 
         return new PlaylistContentResult(

ErsatzTV.Core/Scheduling/Engine/PlaylistHelper.cs

@@ -58,6 +58,7 @@ public class PlaylistHelper(IMediaCollectionRepository mediaCollectionRepository
             state,
             shufflePlaylistItems: false,
             batchSize: Option<int>.None,
+            randomStartPoint: false,
             cancellationToken);
 
         return new PlaylistContentResult(

ErsatzTV.Core/Scheduling/Engine/SchedulingEngine.cs

@@ -257,6 +257,7 @@ public class SchedulingEngine(
             state,
             shufflePlaylistItems: false,
             batchSize: Option<int>.None,
+            randomStartPoint: false,
             CancellationToken.None);
 
         string historyKey = HistoryDetails.KeyForSchedulingContent(key, PlaybackOrder.None);

ErsatzTV.Core/Scheduling/PlaylistEnumerator.cs

@@ -121,6 +121,7 @@ public class PlaylistEnumerator : IMediaCollectionEnumerator
         CollectionEnumeratorState state,
         bool shufflePlaylistItems,
         Option<int> batchSize,
+        bool randomStartPoint,
         CancellationToken cancellationToken)
     {
         var result = new PlaylistEnumerator
@@ -131,6 +132,10 @@ public class PlaylistEnumerator : IMediaCollectionEnumerator
             _batchSize = batchSize
         };
 
+        // random start points only apply to a fresh build with no saved state
+        var random = new Random(state.Seed);
+        randomStartPoint = randomStartPoint && state.Index == 0;
+
         // collections should share enumerators
         var enumeratorMap = new Dictionary<CollectionKey, IMediaCollectionEnumerator>();
         result._allMediaItemIds = [];
@@ -166,6 +171,11 @@ public class PlaylistEnumerator : IMediaCollectionEnumerator
                 switch (playlistItem.PlaybackOrder)
                 {
                     case PlaybackOrder.Chronological:
+                        if (randomStartPoint)
+                        {
+                            initState.Index = random.Next(0, items.Count - 1);
+                        }
+
                         enumerator = new ChronologicalMediaCollectionEnumerator(items, initState);
                         break;
                     // TODO: fix multi episode shuffle?
@@ -187,18 +197,22 @@ public class PlaylistEnumerator : IMediaCollectionEnumerator
                                 CollectionKey.ForPlaylistItem(playlistItem),
                                 cancellationToken),
                             initState,
-                            // TODO: fix this
-                            false,
+                            randomStartPoint,
                             cancellationToken);
                         break;
                     case PlaybackOrder.SeasonEpisode:
-                        // TODO: check random start point?
+                        if (randomStartPoint)
+                        {
+                            initState.Index = random.Next(0, items.Count - 1);
+                        }
+
                         enumerator = new SeasonEpisodeMediaCollectionEnumerator(items, initState);
                         // season, episode will filter out season 0, so we may get an empty enumerator back
                         if (enumerator.Count == 0)
                         {
                             enumerator = null;
                         }
+
                         break;
                     case PlaybackOrder.Random:
                         enumerator = new RandomizedMediaCollectionEnumerator(items, initState);

ErsatzTV.Core/Scheduling/PlayoutBuilder.cs

@@ -1325,6 +1325,7 @@ public class PlayoutBuilder : IPlayoutBuilder
                     state,
                     marathonShuffleGroups,
                     batchSize: Option<int>.None,
+                    randomStartPoint,
                     cancellationToken);
             }
         }

ErsatzTV.Core/Scheduling/YamlScheduling/EnumeratorCache.cs

@@ -175,6 +175,7 @@ public class EnumeratorCache(IMediaCollectionRepository mediaCollectionRepositor
                 state,
                 shufflePlaylistItems: false,
                 batchSize: Option<int>.None,
+                randomStartPoint: false,
                 cancellationToken);
         }