add "shuffle in order" playback order for multi-collections (#338)

* add "shuffle in order" option for multi-collections

* use balanced shuffle instead of random

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
+### Added
+- Add `Shuffle In Order` playback order for multi-collections.
+  - This is useful for randomizing multiple collections/shows on a single channel, while each collection maintains proper ordering (custom or chronological)
+
 ### Fixed
 - Fix bug parsing ffprobe output in cultures where `.` is a group/thousands separator
   - This bug likely prevented ETV from scheduling correctly or working at all in those cultures

ErsatzTV.Application/ProgramSchedules/Commands/ProgramScheduleItemCommandBase.cs

@@ -24,6 +24,23 @@ namespace ErsatzTV.Application.ProgramSchedules.Commands
             IProgramScheduleItemRequest item,
             ProgramSchedule programSchedule)
         {
+            if (item.MultiCollectionId.HasValue)
+            {
+                switch (item.PlaybackOrder)
+                {
+                    case PlaybackOrder.Chronological:
+                    case PlaybackOrder.Random:
+                        return BaseError.New($"Invalid playback order for multi collection: '{item.PlaybackOrder}'");
+                    case PlaybackOrder.Shuffle:
+                    case PlaybackOrder.ShuffleInOrder:
+                        break;
+                }
+            }
+            else if (item.PlaybackOrder == PlaybackOrder.ShuffleInOrder)
+            {
+                return BaseError.New("Invalid playback order: 'Shuffle In Order'");
+            }
+
             switch (item.PlayoutMode)
             {
                 case PlayoutMode.Flood:

ErsatzTV.Application/ProgramSchedules/Commands/ReplaceProgramScheduleItemsHandler.cs

@@ -112,7 +112,5 @@ namespace ErsatzTV.Application.ProgramSchedules.Commands
             int? CollectionId,
             int? MediaItemId,
             int? MultiCollectionId);
-
-        private record CollectionKeyOrder(CollectionKey Key, PlaybackOrder PlaybackOrder);
     }
 }

ErsatzTV.Core/Domain/PlaybackOrder.cs

@@ -4,6 +4,7 @@
     {
         Chronological = 1,
         Random = 2,
-        Shuffle = 3
+        Shuffle = 3,
+        ShuffleInOrder = 4
     }
 }

ErsatzTV.Core/Scheduling/PlayoutBuilder.cs

@@ -567,6 +567,10 @@ namespace ErsatzTV.Core.Scheduling
                     return new ShuffledMediaCollectionEnumerator(
                         await GetGroupedMediaItemsForShuffle(playout, mediaItems, collectionKey),
                         state);
+                case PlaybackOrder.ShuffleInOrder:
+                    return new ShuffleInOrderCollectionEnumerator(
+                        await GetCollectionItemsForShuffleInOrder(collectionKey),
+                        state);
                 default:
                     // TODO: handle this error case differently?
                     return new RandomizedMediaCollectionEnumerator(mediaItems, state);
@@ -593,6 +597,19 @@ namespace ErsatzTV.Core.Scheduling
                 : mediaItems.Map(mi => new GroupedMediaItem(mi, null)).ToList();
         }
 
+        private async Task<List<CollectionWithItems>> GetCollectionItemsForShuffleInOrder(CollectionKey collectionKey)
+        {
+            var result = new List<CollectionWithItems>();
+
+            if (collectionKey.MultiCollectionId != null)
+            {
+                result = await _mediaCollectionRepository.GetMultiCollectionCollections(
+                    collectionKey.MultiCollectionId.Value);
+            }
+
+            return result;
+        }
+
         private static string DisplayTitle(MediaItem mediaItem)
         {
             switch (mediaItem)

ErsatzTV.Core/Scheduling/ShuffleInOrderCollectionEnumerator.cs

@@ -0,0 +1,196 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Scheduling;
+using LanguageExt;
+using static LanguageExt.Prelude;
+
+namespace ErsatzTV.Core.Scheduling
+{
+    public class ShuffleInOrderCollectionEnumerator : IMediaCollectionEnumerator
+    {
+        private readonly IList<CollectionWithItems> _collections;
+        private readonly int _mediaItemCount;
+        private Random _random;
+        private IList<MediaItem> _shuffled;
+
+        public ShuffleInOrderCollectionEnumerator(
+            IList<CollectionWithItems> collections,
+            CollectionEnumeratorState state)
+        {
+            _collections = collections;
+            _mediaItemCount = collections.Sum(c => c.MediaItems.Count);
+
+            if (state.Index >= _mediaItemCount)
+            {
+                state.Index = 0;
+                state.Seed = new Random(state.Seed).Next();
+            }
+            
+            _random = new Random(state.Seed);
+            _shuffled = Shuffle(_collections, _random);
+            
+            State = new CollectionEnumeratorState { Seed = state.Seed };
+            while (State.Index < state.Index)
+            {
+                MoveNext();
+            }
+        }
+
+        public CollectionEnumeratorState State { get; }
+        
+        public Option<MediaItem> Current => _shuffled.Any() ? _shuffled[State.Index % _mediaItemCount] : None;
+
+        public void MoveNext()
+        {
+            if ((State.Index + 1) % _shuffled.Count == 0)
+            {
+                Option<MediaItem> tail = Current;
+
+                State.Index = 0;
+                do
+                {
+                    State.Seed = _random.Next();
+                    _random = new Random(State.Seed);
+                    _shuffled = Shuffle(_collections, _random);
+                } while (_collections.Count > 1 && Current == tail);
+            }
+            else
+            {
+                State.Index++;
+            }
+
+            State.Index %= _shuffled.Count;
+        }
+        
+        private IList<MediaItem> Shuffle(IList<CollectionWithItems> collections, Random random)
+        {
+            // based on https://keyj.emphy.de/balanced-shuffle/
+            
+            var orderedCollections = collections
+                .Filter(c => c.ScheduleAsGroup)
+                .Map(c => new OrderedCollection { Index = 0, Items = OrderItems(c) })
+                .ToList();
+
+            if (collections.Any(c => !c.ScheduleAsGroup))
+            {
+                orderedCollections.Add(
+                    new OrderedCollection
+                    {
+                        Index = 0,
+                        Items = Shuffle(
+                            collections.Filter(c => !c.ScheduleAsGroup).SelectMany(c => c.MediaItems.Map(Some)),
+                            random)
+                    });
+            }
+
+            List<OrderedCollection> filled = Fill(orderedCollections, random);
+
+            var result = new List<MediaItem>();
+            for (var i = 0; i < filled[0].Items.Count; i++)
+            {
+                var batch = filled.Select(collection => collection.Items[i]).ToList();
+                foreach (Option<MediaItem> maybeItem in Shuffle(batch, random))
+                {
+                    result.AddRange(maybeItem);
+                }
+            }
+
+            return result;
+        }
+
+        private List<OrderedCollection> Fill(List<OrderedCollection> orderedCollections, Random random)
+        {
+            var result = new List<OrderedCollection>();
+            int maxLength = orderedCollections.Max(c => c.Items.Count);
+
+            foreach (OrderedCollection collection in orderedCollections)
+            {
+                var items = new Queue<Option<MediaItem>>(collection.Items);
+                var spaces = new Queue<Option<MediaItem>>(
+                    Range(0, maxLength - collection.Items.Count).Map(_ => Option<MediaItem>.None).ToList());
+
+                Queue<Option<MediaItem>> smaller = collection.Items.Count < maxLength - collection.Items.Count
+                    ? items
+                    : spaces;
+                Queue<Option<MediaItem>> larger = collection.Items.Count < maxLength - collection.Items.Count
+                    ? spaces
+                    : items;
+
+                var ordered = new List<Option<MediaItem>>();
+                
+                int k = smaller.Count;
+                while (k > 0)
+                {
+                    int n = maxLength - ordered.Count;
+                    
+                    // compute optimal length +/- 10%
+                    double optimalLength = n / (double)k + (random.NextDouble() - 0.5) / 5.0;
+                    int r = Math.Clamp((int)optimalLength, 1, maxLength - k + 1);
+                    ordered.Add(smaller.Dequeue());
+                    for (var i = 0; i < r - 1; i++)
+                    {
+                        ordered.Add(larger.Dequeue());
+                    }
+
+                    k--;
+                }
+
+                if (smaller.Any())
+                {
+                    ordered.AddRange(smaller);
+                }
+
+                if (larger.Any())
+                {
+                    ordered.AddRange(larger);
+                }
+
+                int offset = random.Next(ordered.Count);
+                result.Add(
+                    new OrderedCollection
+                    {
+                        Index = 0,
+                        Items = ordered.Skip(offset).Concat(ordered.Take(offset)).ToList()
+                    });
+            }
+
+            return result;
+        }
+
+        private static IList<Option<MediaItem>> OrderItems(CollectionWithItems collectionWithItems)
+        {
+            if (collectionWithItems.UseCustomOrder)
+            {
+                return collectionWithItems.MediaItems.Map(Some).ToList();
+            }
+
+            return collectionWithItems.MediaItems
+                .OrderBy(identity, new ChronologicalMediaComparer())
+                .Map(Some)
+                .ToList();
+        }
+        
+        private static IList<Option<MediaItem>> Shuffle(IEnumerable<Option<MediaItem>> list, Random random)
+        {
+            Option<MediaItem>[] copy = list.ToArray();
+
+            int n = copy.Length;
+            while (n > 1)
+            {
+                n--;
+                int k = random.Next(n + 1);
+                (copy[k], copy[n]) = (copy[n], copy[k]);
+            }
+
+            return copy;
+        }
+
+        private class OrderedCollection
+        {
+            public int Index { get; set; }
+            public IList<Option<MediaItem>> Items { get; set; }
+        }
+    }
+}

ErsatzTV.Core/Scheduling/ShuffledMediaCollectionEnumerator.cs

@@ -73,9 +73,7 @@ namespace ErsatzTV.Core.Scheduling
             {
                 n--;
                 int k = random.Next(n + 1);
-                GroupedMediaItem value = copy[k];
-                copy[k] = copy[n];
-                copy[n] = value;
+                (copy[k], copy[n]) = (copy[n], copy[k]);
             }
 
             return GroupedMediaItem.FlattenGroups(copy, _mediaItemCount);

ErsatzTV.Infrastructure/Plex/PlexServerApiClient.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net.Http;
 using System.Threading.Tasks;
 using System.Xml.Serialization;
 using ErsatzTV.Core;
@@ -35,7 +36,12 @@ namespace ErsatzTV.Infrastructure.Plex
         {
             try
             {
-                IPlexServerApi service = RestService.For<IPlexServerApi>(connection.Uri);
+                IPlexServerApi service = RestService.For<IPlexServerApi>(
+                    new HttpClient
+                    {
+                        BaseAddress = new Uri(connection.Uri),
+                        Timeout = TimeSpan.FromSeconds(10)
+                    });
                 List<PlexLibraryResponse> directory =
                     await service.GetLibraries(token.AuthToken).Map(r => r.MediaContainer.Directory);
                 return directory

ErsatzTV/Pages/ScheduleItemsEditor.razor

@@ -145,10 +145,17 @@
                                                  SearchFunc="@SearchArtists"
                                                  ToStringFunc="@(s => s?.Name)"/>
                             }
-                            <MudSelect Class="mt-3" Label="Playback Order" @bind-Value="@_selectedItem.PlaybackOrder" For="@(() => _selectedItem.PlaybackOrder)" Disabled="@(_selectedItem.CollectionType == ProgramScheduleItemCollectionType.MultiCollection)">
-                                @foreach (PlaybackOrder playbackOrder in Enum.GetValues<PlaybackOrder>())
+                            <MudSelect Class="mt-3" Label="Playback Order" @bind-Value="@_selectedItem.PlaybackOrder" For="@(() => _selectedItem.PlaybackOrder)">
+                                @if (_selectedItem.CollectionType == ProgramScheduleItemCollectionType.MultiCollection)
                                 {
-                                    <MudSelectItem Value="@playbackOrder">@playbackOrder</MudSelectItem>
+                                    <MudSelectItem Value="PlaybackOrder.Shuffle">Shuffle</MudSelectItem>
+                                    <MudSelectItem Value="PlaybackOrder.ShuffleInOrder">Shuffle In Order</MudSelectItem>
+                                }
+                                else
+                                {
+                                    <MudSelectItem Value="PlaybackOrder.Chronological">Chronological</MudSelectItem>
+                                    <MudSelectItem Value="PlaybackOrder.Random">Random</MudSelectItem>
+                                    <MudSelectItem Value="PlaybackOrder.Shuffle">Shuffle</MudSelectItem>
                                 }
                             </MudSelect>
                             <MudSelect Class="mt-3" Label="Playout Mode" @bind-Value="@_selectedItem.PlayoutMode" For="@(() => _selectedItem.PlayoutMode)">