From 015f5e9798dcfd22d991b8d7d65efc7081319827 Mon Sep 17 00:00:00 2001
From: Jason Dove <1695733+jasongdove@users.noreply.github.com>
Date: Thu, 22 Jun 2023 09:40:20 -0500
Subject: [PATCH] fix playout build loop that was recently introduced (#1318)

---
 .../Domain/CollectionEnumeratorState.cs       |  2 +-
 .../Scheduling/IMediaCollectionEnumerator.cs  |  2 +-
 .../ChronologicalMediaCollectionEnumerator.cs |  5 ++--
 .../CustomOrderCollectionEnumerator.cs        |  5 ++--
 .../PlayoutModeSchedulerDuration.cs           | 23 +++++++----------
 .../Scheduling/PlayoutModeSchedulerFlood.cs   | 25 ++++++++-----------
 .../RandomizedMediaCollectionEnumerator.cs    |  5 ++--
 .../SeasonEpisodeMediaCollectionEnumerator.cs |  5 ++--
 .../ShuffleInOrderCollectionEnumerator.cs     | 11 ++++++--
 .../ShuffledMediaCollectionEnumerator.cs      | 11 ++++++--
 ...MultiEpisodeShuffleCollectionEnumerator.cs | 23 ++++++++---------
 11 files changed, 62 insertions(+), 55 deletions(-)

diff --git a/ErsatzTV.Core/Domain/CollectionEnumeratorState.cs b/ErsatzTV.Core/Domain/CollectionEnumeratorState.cs
index 167632d1..3cf6a310 100644
--- a/ErsatzTV.Core/Domain/CollectionEnumeratorState.cs
+++ b/ErsatzTV.Core/Domain/CollectionEnumeratorState.cs
@@ -4,5 +4,5 @@ public class CollectionEnumeratorState
 {
     public int Seed { get; set; }
     public int Index { get; set; }
-    public CollectionEnumeratorState Clone() => new CollectionEnumeratorState { Seed = Seed, Index = Index };
+    public CollectionEnumeratorState Clone() => new() { Seed = Seed, Index = Index };
 }
diff --git a/ErsatzTV.Core/Interfaces/Scheduling/IMediaCollectionEnumerator.cs b/ErsatzTV.Core/Interfaces/Scheduling/IMediaCollectionEnumerator.cs
index bfa5c909..3a6c210e 100644
--- a/ErsatzTV.Core/Interfaces/Scheduling/IMediaCollectionEnumerator.cs
+++ b/ErsatzTV.Core/Interfaces/Scheduling/IMediaCollectionEnumerator.cs
@@ -4,7 +4,7 @@ namespace ErsatzTV.Core.Interfaces.Scheduling;
 
 public interface IMediaCollectionEnumerator
 {
-    IMediaCollectionEnumerator Clone(CollectionEnumeratorState state, CancellationToken cancellationToken);
+    void ResetState(CollectionEnumeratorState state);
     CollectionEnumeratorState State { get; }
     Option<MediaItem> Current { get; }
     void MoveNext();
diff --git a/ErsatzTV.Core/Scheduling/ChronologicalMediaCollectionEnumerator.cs b/ErsatzTV.Core/Scheduling/ChronologicalMediaCollectionEnumerator.cs
index 537cc929..60c52bc6 100644
--- a/ErsatzTV.Core/Scheduling/ChronologicalMediaCollectionEnumerator.cs
+++ b/ErsatzTV.Core/Scheduling/ChronologicalMediaCollectionEnumerator.cs
@@ -31,9 +31,10 @@ public sealed class ChronologicalMediaCollectionEnumerator : IMediaCollectionEnu
         }
     }
 
-    public IMediaCollectionEnumerator Clone(CollectionEnumeratorState state, CancellationToken cancellationToken)
+    public void ResetState(CollectionEnumeratorState state)
     {
-        return new ChronologicalMediaCollectionEnumerator(_sortedMediaItems, state);
+        // seed doesn't matter in chronological
+        State.Index = state.Index;
     }
 
     public CollectionEnumeratorState State { get; }
diff --git a/ErsatzTV.Core/Scheduling/CustomOrderCollectionEnumerator.cs b/ErsatzTV.Core/Scheduling/CustomOrderCollectionEnumerator.cs
index c7528a54..b311a829 100644
--- a/ErsatzTV.Core/Scheduling/CustomOrderCollectionEnumerator.cs
+++ b/ErsatzTV.Core/Scheduling/CustomOrderCollectionEnumerator.cs
@@ -35,9 +35,10 @@ public class CustomOrderCollectionEnumerator : IMediaCollectionEnumerator
         }
     }
 
-    public IMediaCollectionEnumerator Clone(CollectionEnumeratorState state, CancellationToken cancellationToken)
+    public void ResetState(CollectionEnumeratorState state)
     {
-        return new CustomOrderCollectionEnumerator(_collection, _mediaItems, state);
+        // seed doesn't matter here
+        State.Index = state.Index;
     }
 
     public CollectionEnumeratorState State { get; }
diff --git a/ErsatzTV.Core/Scheduling/PlayoutModeSchedulerDuration.cs b/ErsatzTV.Core/Scheduling/PlayoutModeSchedulerDuration.cs
index 1e5589fe..85a4b22f 100644
--- a/ErsatzTV.Core/Scheduling/PlayoutModeSchedulerDuration.cs
+++ b/ErsatzTV.Core/Scheduling/PlayoutModeSchedulerDuration.cs
@@ -122,16 +122,15 @@ public class PlayoutModeSchedulerDuration : PlayoutModeSchedulerBase<ProgramSche
 
                 DateTimeOffset durationFinish = nextState.DurationFinish.IfNone(SystemTime.MaxValueUtc);
                 
-                var enumeratorClones = new Dictionary<CollectionKey, IMediaCollectionEnumerator>();
+                var enumeratorStates = new Dictionary<CollectionKey, CollectionEnumeratorState>();
                 foreach ((CollectionKey key, IMediaCollectionEnumerator enumerator) in collectionEnumerators)
                 {
-                    IMediaCollectionEnumerator clone = enumerator.Clone(enumerator.State.Clone(), cancellationToken);
-                    enumeratorClones.Add(key, clone);
+                    enumeratorStates.Add(key, enumerator.State.Clone());
                 }
 
                 List<PlayoutItem> maybePlayoutItems = AddFiller(
                     nextState,
-                    enumeratorClones,
+                    collectionEnumerators,
                     scheduleItem,
                     playoutItem,
                     itemChapters,
@@ -147,16 +146,6 @@ public class PlayoutModeSchedulerDuration : PlayoutModeSchedulerBase<ProgramSche
                     // LogScheduledItem(scheduleItem, mediaItem, itemStartTime);
                     playoutItems.AddRange(maybePlayoutItems);
 
-                    // update original enumerators
-                    foreach ((CollectionKey key, IMediaCollectionEnumerator enumerator) in collectionEnumerators)
-                    {
-                        IMediaCollectionEnumerator clone = enumeratorClones[key];
-                        while (enumerator.State.Seed != clone.State.Seed || enumerator.State.Index != clone.State.Index)
-                        {
-                            enumerator.MoveNext();
-                        }
-                    }
-
                     nextState = nextState with
                     {
                         CurrentTime = itemEndTimeWithFiller,
@@ -171,6 +160,12 @@ public class PlayoutModeSchedulerDuration : PlayoutModeSchedulerBase<ProgramSche
                 }
                 else
                 {
+                    // reset enumerators
+                    foreach ((CollectionKey key, IMediaCollectionEnumerator enumerator) in collectionEnumerators)
+                    {
+                        enumerator.ResetState(enumeratorStates[key]);
+                    }
+                    
                     TimeSpan durationBlock = itemEndTimeWithFiller - itemStartTime;
                     if (itemEndTimeWithFiller - itemStartTime > scheduleItem.PlayoutDuration)
                     {
diff --git a/ErsatzTV.Core/Scheduling/PlayoutModeSchedulerFlood.cs b/ErsatzTV.Core/Scheduling/PlayoutModeSchedulerFlood.cs
index 4f17997c..e92fc9b0 100644
--- a/ErsatzTV.Core/Scheduling/PlayoutModeSchedulerFlood.cs
+++ b/ErsatzTV.Core/Scheduling/PlayoutModeSchedulerFlood.cs
@@ -74,16 +74,15 @@ public class PlayoutModeSchedulerFlood : PlayoutModeSchedulerBase<ProgramSchedul
                     ? GetStartTimeAfter(nextState with { InFlood = false }, peekScheduleItem)
                     : DateTimeOffset.MaxValue;
 
-            var enumeratorClones = new Dictionary<CollectionKey, IMediaCollectionEnumerator>();
+            var enumeratorStates = new Dictionary<CollectionKey, CollectionEnumeratorState>();
             foreach ((CollectionKey key, IMediaCollectionEnumerator enumerator) in collectionEnumerators)
             {
-                IMediaCollectionEnumerator clone = enumerator.Clone(enumerator.State.Clone(), cancellationToken);
-                enumeratorClones.Add(key, clone);
+                enumeratorStates.Add(key, enumerator.State.Clone());
             }
 
             List<PlayoutItem> maybePlayoutItems = AddFiller(
                 nextState,
-                enumeratorClones,
+                collectionEnumerators,
                 scheduleItem,
                 playoutItem,
                 itemChapters,
@@ -102,16 +101,6 @@ public class PlayoutModeSchedulerFlood : PlayoutModeSchedulerBase<ProgramSchedul
                 playoutItems.AddRange(maybePlayoutItems);
                 // LogScheduledItem(scheduleItem, mediaItem, itemStartTime);
 
-                // update original enumerators
-                foreach ((CollectionKey key, IMediaCollectionEnumerator enumerator) in collectionEnumerators)
-                {
-                    IMediaCollectionEnumerator clone = enumeratorClones[key];
-                    while (enumerator.State.Seed != clone.State.Seed || enumerator.State.Index != clone.State.Index)
-                    {
-                        enumerator.MoveNext();
-                    }
-                }
-
                 nextState = nextState with
                 {
                     CurrentTime = itemEndTimeWithFiller,
@@ -125,6 +114,14 @@ public class PlayoutModeSchedulerFlood : PlayoutModeSchedulerBase<ProgramSchedul
 
                 contentEnumerator.MoveNext();
             }
+            else
+            {
+                // reset enumerators
+                foreach ((CollectionKey key, IMediaCollectionEnumerator enumerator) in collectionEnumerators)
+                {
+                    enumerator.ResetState(enumeratorStates[key]);
+                }
+            }
         }
 
         // _logger.LogDebug(
diff --git a/ErsatzTV.Core/Scheduling/RandomizedMediaCollectionEnumerator.cs b/ErsatzTV.Core/Scheduling/RandomizedMediaCollectionEnumerator.cs
index fe5dba05..d895ee3d 100644
--- a/ErsatzTV.Core/Scheduling/RandomizedMediaCollectionEnumerator.cs
+++ b/ErsatzTV.Core/Scheduling/RandomizedMediaCollectionEnumerator.cs
@@ -27,9 +27,10 @@ public class RandomizedMediaCollectionEnumerator : IMediaCollectionEnumerator
         }
     }
 
-    public IMediaCollectionEnumerator Clone(CollectionEnumeratorState state, CancellationToken cancellationToken)
+    public void ResetState(CollectionEnumeratorState state)
     {
-        return new RandomizedMediaCollectionEnumerator(_mediaItems, state);
+        // seed never changes here, no need to reset
+        State.Index = state.Index;
     }
 
     public CollectionEnumeratorState State { get; }
diff --git a/ErsatzTV.Core/Scheduling/SeasonEpisodeMediaCollectionEnumerator.cs b/ErsatzTV.Core/Scheduling/SeasonEpisodeMediaCollectionEnumerator.cs
index 60068051..fc3f4694 100644
--- a/ErsatzTV.Core/Scheduling/SeasonEpisodeMediaCollectionEnumerator.cs
+++ b/ErsatzTV.Core/Scheduling/SeasonEpisodeMediaCollectionEnumerator.cs
@@ -31,9 +31,10 @@ public sealed class SeasonEpisodeMediaCollectionEnumerator : IMediaCollectionEnu
         }
     }
 
-    public IMediaCollectionEnumerator Clone(CollectionEnumeratorState state, CancellationToken cancellationToken)
+    public void ResetState(CollectionEnumeratorState state)
     {
-        return new SeasonEpisodeMediaCollectionEnumerator(_sortedMediaItems, state);
+        // seed doesn't matter here
+        State.Index = state.Index;
     }
 
     public CollectionEnumeratorState State { get; }
diff --git a/ErsatzTV.Core/Scheduling/ShuffleInOrderCollectionEnumerator.cs b/ErsatzTV.Core/Scheduling/ShuffleInOrderCollectionEnumerator.cs
index c7e6fb43..f712e425 100644
--- a/ErsatzTV.Core/Scheduling/ShuffleInOrderCollectionEnumerator.cs
+++ b/ErsatzTV.Core/Scheduling/ShuffleInOrderCollectionEnumerator.cs
@@ -43,9 +43,16 @@ public class ShuffleInOrderCollectionEnumerator : IMediaCollectionEnumerator
         }
     }
 
-    public IMediaCollectionEnumerator Clone(CollectionEnumeratorState state, CancellationToken cancellationToken)
+    public void ResetState(CollectionEnumeratorState state)
     {
-        return new ShuffleInOrderCollectionEnumerator(_collections, state, _randomStartPoint, cancellationToken);
+        // only re-shuffle if needed
+        if (State.Seed != state.Seed)
+        {
+            _random = new Random(state.Seed);
+            _shuffled = Shuffle(_collections, _random);
+        }
+
+        State.Index = state.Index;
     }
 
     public CollectionEnumeratorState State { get; }
diff --git a/ErsatzTV.Core/Scheduling/ShuffledMediaCollectionEnumerator.cs b/ErsatzTV.Core/Scheduling/ShuffledMediaCollectionEnumerator.cs
index 610093bc..691e3caf 100644
--- a/ErsatzTV.Core/Scheduling/ShuffledMediaCollectionEnumerator.cs
+++ b/ErsatzTV.Core/Scheduling/ShuffledMediaCollectionEnumerator.cs
@@ -40,9 +40,16 @@ public class ShuffledMediaCollectionEnumerator : IMediaCollectionEnumerator
         }
     }
 
-    public IMediaCollectionEnumerator Clone(CollectionEnumeratorState state, CancellationToken cancellationToken)
+    public void ResetState(CollectionEnumeratorState state)
     {
-        return new ShuffledMediaCollectionEnumerator(_mediaItems, state, cancellationToken);
+        // only re-shuffle if needed
+        if (State.Seed != state.Seed)
+        {
+            _random = new CloneableRandom(state.Seed);
+            _shuffled = Shuffle(_mediaItems, _random);
+        }
+
+        State.Index = state.Index;
     }
 
     public CollectionEnumeratorState State { get; }
diff --git a/ErsatzTV.Infrastructure/Scheduling/MultiEpisodeShuffleCollectionEnumerator.cs b/ErsatzTV.Infrastructure/Scheduling/MultiEpisodeShuffleCollectionEnumerator.cs
index 7360b659..6da9ddbb 100644
--- a/ErsatzTV.Infrastructure/Scheduling/MultiEpisodeShuffleCollectionEnumerator.cs
+++ b/ErsatzTV.Infrastructure/Scheduling/MultiEpisodeShuffleCollectionEnumerator.cs
@@ -10,8 +10,6 @@ namespace ErsatzTV.Infrastructure.Scheduling;
 public class MultiEpisodeShuffleCollectionEnumerator : IMediaCollectionEnumerator
 {
     private readonly CancellationToken _cancellationToken;
-    private readonly IList<MediaItem> _mediaItems;
-    private readonly IScriptEngine _scriptEngine;
     private readonly ILogger _logger;
     private readonly int _mediaItemCount;
     private readonly Dictionary<int, List<MediaItem>> _mediaItemGroups;
@@ -21,15 +19,13 @@ public class MultiEpisodeShuffleCollectionEnumerator : IMediaCollectionEnumerato
     private readonly Lazy<Option<TimeSpan>> _lazyMinimumDuration;
 
     public MultiEpisodeShuffleCollectionEnumerator(
-        IList<MediaItem> mediaItems,
+        ICollection<MediaItem> mediaItems,
         CollectionEnumeratorState state,
         IScriptEngine scriptEngine,
         string scriptFile,
         ILogger logger,
         CancellationToken cancellationToken)
     {
-        _mediaItems = mediaItems;
-        _scriptEngine = scriptEngine;
         _logger = logger;
         _cancellationToken = cancellationToken;
 
@@ -91,15 +87,16 @@ public class MultiEpisodeShuffleCollectionEnumerator : IMediaCollectionEnumerato
         }
     }
 
-    public IMediaCollectionEnumerator Clone(CollectionEnumeratorState state, CancellationToken cancellationToken)
+    public void ResetState(CollectionEnumeratorState state)
     {
-        return new MultiEpisodeShuffleCollectionEnumerator(
-            _mediaItems,
-            state,
-            _scriptEngine,
-            null,
-            _logger,
-            cancellationToken);
+        // only re-shuffle if needed
+        if (State.Seed != state.Seed)
+        {
+            _random = new CloneableRandom(state.Seed);
+            _shuffled = Shuffle(_random);
+        }
+
+        State.Index = state.Index;
     }
 
     public CollectionEnumeratorState State { get; }