[scheduling] Add a new mode RandomRotation that randomly picks an item from a randomly choosen group (show/artist) for block schedule (#1885)

* init * minor naming change * address to comments round 1 * update dependencies * formatting * make sure it rotates * update changelog --------- Co-authored-by: Jason Dove <1695733+jasongdove@users.noreply.github.com>
2024-09-10 13:36:20 -05:00
parent 91e85cc9c1
commit f40eaef898
16 changed files with 152 additions and 16 deletions
@@ -0,0 +1,96 @@
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Extensions;
+using ErsatzTV.Core.Interfaces.Scheduling;
+
+namespace ErsatzTV.Core.Scheduling;
+
+public class RandomizedRotatingMediaCollectionEnumerator : IMediaCollectionEnumerator
+{
+    private readonly Lazy<Option<TimeSpan>> _lazyMinimumDuration;
+    private readonly IList<MediaItem> _mediaItems;
+    private readonly Random _random;
+    private readonly Dictionary<int, IList<int>> _groupMedia;
+    private int _index;
+    private int _groupNumber;
+
+    public RandomizedRotatingMediaCollectionEnumerator(IList<MediaItem> mediaItems, CollectionEnumeratorState state)
+    {
+        CurrentIncludeInProgramGuide = Option<bool>.None;
+
+        _mediaItems = mediaItems;
+        _lazyMinimumDuration =
+            new Lazy<Option<TimeSpan>>(
+                () => _mediaItems.Bind(i => i.GetNonZeroDuration()).OrderBy(identity).HeadOrNone());
+        _random = new Random(state.Seed);
+
+        _groupMedia = new Dictionary<int, IList<int>>();
+        for (int i = 0; i < mediaItems.Count; i++)
+        {
+            int id = mediaItems[i] switch
+            {
+                Episode e => e.Season.ShowId,
+                MusicVideo mv => mv.ArtistId,
+                _ => mediaItems[i].Id
+            };
+
+            if (_groupMedia.TryGetValue(id, out IList<int> newList))
+            {
+                newList.Add(i);
+            }
+            else
+            {
+                _groupMedia.Add(id, new List<int> { i });
+            }
+        }
+
+        _groupNumber = 0;
+
+        State = new CollectionEnumeratorState { Seed = state.Seed };
+        // we want to move at least once so we start with a random item and not the first
+        // because _index defaults to 0
+        while (State.Index <= state.Index)
+        {
+            MoveNext();
+        }
+    }
+
+    public void ResetState(CollectionEnumeratorState state) =>
+        // seed never changes here, no need to reset
+        State.Index = state.Index;
+
+    public CollectionEnumeratorState State { get; }
+
+    public Option<MediaItem> Current => _mediaItems.Any() ? _mediaItems[_index] : None;
+    public Option<bool> CurrentIncludeInProgramGuide { get; }
+
+    public void MoveNext()
+    {
+        IList<int> groups = _groupMedia.Keys.ToList();
+        int nextRandom = _random.Next();
+
+        int groupNumber = nextRandom % groups.Count;
+        if (_groupNumber == groupNumber)
+        {
+            if (groupNumber == groups.Count - 1)
+            {
+                _groupNumber = 0;
+            }
+            else
+            {
+                _groupNumber = groupNumber + 1;
+            }
+        }
+        else
+        {
+            _groupNumber = groupNumber;
+        }
+
+        int itemNumber = nextRandom % _groupMedia[groups[_groupNumber]].Count;
+        _index = _groupMedia[groups[_groupNumber]][itemNumber];
+        State.Index++;
+    }
+
+    public Option<TimeSpan> MinimumDuration => _lazyMinimumDuration.Value;
+
+    public int Count => _mediaItems.Count;
+}