add option to shuffle schedule items (#652)

* add schedule setting

* it works

* fix tests

* update readme

* rebuild all playouts

CHANGELOG.md

@@ -10,6 +10,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Added
 - Add configurable channel group (M3U) and categories (XMLTV)
+- Add `Shuffle Schedule Items` option to schedule configuration
+  - When this is enabled, schedule items will be shuffled rather than looped in order
+  - **To support this, all playouts will be rebuilt (one time) after upgrading to this version**
 
 ### Changed
 - Disable framerate normalization by default and on all ffmpeg profiles

ErsatzTV.Application/ProgramSchedules/Commands/CreateProgramSchedule.cs

@@ -8,5 +8,6 @@ namespace ErsatzTV.Application.ProgramSchedules.Commands
     public record CreateProgramSchedule(
         string Name,
         bool KeepMultiPartEpisodesTogether,
-        bool TreatCollectionsAsShows) : IRequest<Either<BaseError, CreateProgramScheduleResult>>;
+        bool TreatCollectionsAsShows,
+        bool ShuffleScheduleItems) : IRequest<Either<BaseError, CreateProgramScheduleResult>>;
 }

ErsatzTV.Application/ProgramSchedules/Commands/CreateProgramScheduleHandler.cs

@@ -50,7 +50,8 @@ namespace ErsatzTV.Application.ProgramSchedules.Commands
                     {
                         Name = name,
                         KeepMultiPartEpisodesTogether = keepMultiPartEpisodesTogether,
-                        TreatCollectionsAsShows = keepMultiPartEpisodesTogether && request.TreatCollectionsAsShows
+                        TreatCollectionsAsShows = keepMultiPartEpisodesTogether && request.TreatCollectionsAsShows,
+                        ShuffleScheduleItems = request.ShuffleScheduleItems
                     };
                 });
 

ErsatzTV.Application/ProgramSchedules/Commands/UpdateProgramSchedule.cs

@@ -10,5 +10,6 @@ namespace ErsatzTV.Application.ProgramSchedules.Commands
         int ProgramScheduleId,
         string Name,
         bool KeepMultiPartEpisodesTogether,
-        bool TreatCollectionsAsShows) : IRequest<Either<BaseError, UpdateProgramScheduleResult>>;
+        bool TreatCollectionsAsShows,
+        bool ShuffleScheduleItems) : IRequest<Either<BaseError, UpdateProgramScheduleResult>>;
 }

ErsatzTV.Application/ProgramSchedules/Commands/UpdateProgramScheduleHandler.cs

@@ -31,7 +31,7 @@ namespace ErsatzTV.Application.ProgramSchedules.Commands
             UpdateProgramSchedule request,
             CancellationToken cancellationToken)
         {
-            await using TvContext dbContext = _dbContextFactory.CreateDbContext();
+            await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
 
             Validation<BaseError, ProgramSchedule> validation = await Validate(dbContext, request);
             return await validation.Apply(ps => ApplyUpdateRequest(dbContext, ps, request));
@@ -45,12 +45,14 @@ namespace ErsatzTV.Application.ProgramSchedules.Commands
             // we need to rebuild playouts if the playback order or keep multi-episodes has been modified
             bool needToRebuildPlayout =
                 programSchedule.KeepMultiPartEpisodesTogether != request.KeepMultiPartEpisodesTogether ||
-                programSchedule.TreatCollectionsAsShows != request.TreatCollectionsAsShows;
+                programSchedule.TreatCollectionsAsShows != request.TreatCollectionsAsShows ||
+                programSchedule.ShuffleScheduleItems != request.ShuffleScheduleItems;
 
             programSchedule.Name = request.Name;
             programSchedule.KeepMultiPartEpisodesTogether = request.KeepMultiPartEpisodesTogether;
             programSchedule.TreatCollectionsAsShows = programSchedule.KeepMultiPartEpisodesTogether &&
                                                       request.TreatCollectionsAsShows;
+            programSchedule.ShuffleScheduleItems = request.ShuffleScheduleItems;
 
             await dbContext.SaveChangesAsync();
 

ErsatzTV.Application/ProgramSchedules/Mapper.cs

@@ -10,7 +10,8 @@ namespace ErsatzTV.Application.ProgramSchedules
                 programSchedule.Id,
                 programSchedule.Name,
                 programSchedule.KeepMultiPartEpisodesTogether,
-                programSchedule.TreatCollectionsAsShows);
+                programSchedule.TreatCollectionsAsShows,
+                programSchedule.ShuffleScheduleItems);
 
         internal static ProgramScheduleItemViewModel ProjectToViewModel(ProgramScheduleItem programScheduleItem) =>
             programScheduleItem switch

ErsatzTV.Application/ProgramSchedules/ProgramScheduleViewModel.cs

@@ -4,5 +4,6 @@
         int Id,
         string Name,
         bool KeepMultiPartEpisodesTogether,
-        bool TreatCollectionsAsShows);
+        bool TreatCollectionsAsShows,
+        bool ShuffleScheduleItems);
 }

ErsatzTV.Application/ProgramSchedules/Queries/GetAllProgramSchedulesHandler.cs

@@ -25,7 +25,8 @@ namespace ErsatzTV.Application.ProgramSchedules.Queries
                         ps.Id,
                         ps.Name,
                         ps.KeepMultiPartEpisodesTogether,
-                        ps.TreatCollectionsAsShows))
+                        ps.TreatCollectionsAsShows,
+                        ps.ShuffleScheduleItems))
                 .ToListAsync(cancellationToken);
         }
     }

ErsatzTV.Application/ProgramSchedules/Queries/GetProgramScheduleByIdHandler.cs

@@ -21,7 +21,7 @@ namespace ErsatzTV.Application.ProgramSchedules.Queries
             GetProgramScheduleById request,
             CancellationToken cancellationToken)
         {
-            await using TvContext dbContext = _dbContextFactory.CreateDbContext();
+            await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
             return await dbContext.ProgramSchedules
                 .SelectOneAsync(ps => ps.Id, ps => ps.Id == request.Id)
                 .MapT(ProjectToViewModel);

ErsatzTV.Application/ProgramSchedules/Queries/GetProgramScheduleItemsHandler.cs

@@ -4,6 +4,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using ErsatzTV.Core.Domain;
 using ErsatzTV.Infrastructure.Data;
+using ErsatzTV.Infrastructure.Extensions;
 using LanguageExt;
 using MediatR;
 using Microsoft.EntityFrameworkCore;
@@ -23,7 +24,11 @@ namespace ErsatzTV.Application.ProgramSchedules.Queries
             GetProgramScheduleItems request,
             CancellationToken cancellationToken)
         {
-            await using TvContext dbContext = _dbContextFactory.CreateDbContext();
+            await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
+
+            Option<ProgramSchedule> maybeProgramSchedule =
+                await dbContext.ProgramSchedules.SelectOneAsync(ps => ps.Id, ps => ps.Id == request.Id);
+
             return await dbContext.ProgramScheduleItems
                 .Filter(psi => psi.ProgramScheduleId == request.Id)
                 .Include(i => i.Collection)
@@ -51,7 +56,29 @@ namespace ErsatzTV.Application.ProgramSchedules.Queries
                 .Include(i => i.TailFiller)
                 .Include(i => i.FallbackFiller)
                 .ToListAsync(cancellationToken)
-                .Map(programScheduleItems => programScheduleItems.Map(ProjectToViewModel).ToList());
+                .Map(
+                    programScheduleItems => programScheduleItems.Map(ProjectToViewModel)
+                        .Map(psi => EnforceProperties(maybeProgramSchedule, psi)).ToList());
+        }
+
+        // shuffled schedule items supports a limited set of properly values
+        private ProgramScheduleItemViewModel EnforceProperties(
+            Option<ProgramSchedule> maybeProgramSchedule,
+            ProgramScheduleItemViewModel item)
+        {
+            foreach (ProgramSchedule programSchedule in maybeProgramSchedule)
+            {
+                if (programSchedule.ShuffleScheduleItems)
+                {
+                    item = item with { StartType = StartType.Dynamic };
+                    if (item.PlayoutMode == PlayoutMode.Flood)
+                    {
+                        item = item with { PlayoutMode = PlayoutMode.One };
+                    }
+                }
+            }
+
+            return item;
         }
     }
 }

ErsatzTV.Core.Tests/Scheduling/PlayoutBuilderTests.cs

@@ -624,8 +624,11 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Anchor = new PlayoutAnchor
                 {
                     NextStart = HoursAfterMidnight(9).UtcDateTime,
-                    NextScheduleItem = items[0],
-                    NextScheduleItemId = 1,
+                    ScheduleItemsEnumeratorState = new CollectionEnumeratorState
+                    {
+                        Index = 0,
+                        Seed = 1
+                    },
                     InFlood = true
                 }
             };
@@ -918,8 +921,11 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Anchor = new PlayoutAnchor
                 {
                     NextStart = HoursAfterMidnight(1).UtcDateTime,
-                    NextScheduleItem = items[0],
-                    NextScheduleItemId = 1,
+                    ScheduleItemsEnumeratorState = new CollectionEnumeratorState
+                    {
+                        Index = 0,
+                        Seed = 1
+                    },
                     MultipleRemaining = 2
                 }
             };
@@ -951,7 +957,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             result.Items[3].StartOffset.TimeOfDay.Should().Be(TimeSpan.FromHours(4));
             result.Items[3].MediaItemId.Should().Be(2);
 
-            result.Anchor.NextScheduleItem.Should().Be(items[1]);
+            result.Anchor.ScheduleItemsEnumeratorState.Index.Should().Be(1);
             result.Anchor.MultipleRemaining.Should().Be(1);
         }
 
@@ -1048,7 +1054,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             result.Items[4].StartOffset.TimeOfDay.Should().Be(TimeSpan.FromHours(4));
             result.Items[4].MediaItemId.Should().Be(5);
 
-            result.Anchor.NextScheduleItem.Should().Be(items[0]);
+            result.Anchor.ScheduleItemsEnumeratorState.Index.Should().Be(0);
             result.Anchor.MultipleRemaining.Should().BeNull();
         }
 
@@ -1116,8 +1122,11 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Anchor = new PlayoutAnchor
                 {
                     NextStart = HoursAfterMidnight(1).UtcDateTime,
-                    NextScheduleItem = items[0],
-                    NextScheduleItemId = 1,
+                    ScheduleItemsEnumeratorState = new CollectionEnumeratorState
+                    {
+                        Index = 0,
+                        Seed = 1
+                    },
                     DurationFinish = HoursAfterMidnight(3).UtcDateTime
                 }
             };
@@ -1149,7 +1158,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             result.Items[3].StartOffset.TimeOfDay.Should().Be(TimeSpan.FromHours(4));
             result.Items[3].MediaItemId.Should().Be(2);
 
-            result.Anchor.NextScheduleItem.Should().Be(items[1]);
+            result.Anchor.ScheduleItemsEnumeratorState.Index.Should().Be(1);
             result.Anchor.DurationFinish.Should().Be(HoursAfterMidnight(6).UtcDateTime);
         }
         
@@ -1284,7 +1293,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             result.Items[11].StartOffset.TimeOfDay.Should().Be(new TimeSpan(5, 55, 0));
             result.Items[11].MediaItemId.Should().Be(3);
             
-            result.Anchor.NextScheduleItem.Should().Be(items[0]);
+            result.Anchor.ScheduleItemsEnumeratorState.Index.Should().Be(0);
             result.Anchor.DurationFinish.Should().BeNull();
         }
         
@@ -1361,7 +1370,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             result.Items[5].StartOffset.TimeOfDay.Should().Be(TimeSpan.FromHours(5));
             result.Items[5].MediaItemId.Should().Be(4);
 
-            result.Anchor.NextScheduleItem.Should().Be(items[0]);
+            result.Anchor.ScheduleItemsEnumeratorState.Index.Should().Be(0);
             result.Anchor.DurationFinish.Should().BeNull();
         }
 

ErsatzTV.Core.Tests/Scheduling/PlayoutModeSchedulerDurationTests.cs

@@ -31,19 +31,25 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 PlaybackOrder = PlaybackOrder.Chronological
             };
 
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
 
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+            
             var scheduler = new PlayoutModeSchedulerDuration(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -51,26 +57,26 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
             playoutItems[0].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
             playoutItems[1].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.AddHours(2));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.AddHours(2));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
             playoutItems[2].GuideFinish.HasValue.Should().BeTrue();
@@ -94,19 +100,25 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 CustomTitle = "Custom Title"
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerDuration(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -114,28 +126,28 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
             playoutItems[0].GuideFinish.HasValue.Should().BeFalse();
             playoutItems[0].CustomTitle.Should().Be("Custom Title");
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems[1].GuideGroup.Should().Be(1);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
             playoutItems[1].GuideFinish.HasValue.Should().BeFalse();
             playoutItems[1].CustomTitle.Should().Be("Custom Title");
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.AddHours(2));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.AddHours(2));
             playoutItems[2].GuideGroup.Should().Be(1);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
             playoutItems[2].GuideFinish.HasValue.Should().BeTrue();
@@ -159,19 +171,25 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 PlaybackOrder = PlaybackOrder.Chronological
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerDuration(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -179,26 +197,26 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
             
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
             playoutItems[0].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
             playoutItems[1].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
             playoutItems[2].GuideFinish.HasValue.Should().BeTrue();
@@ -221,47 +239,53 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 PlaybackOrder = PlaybackOrder.Chronological
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerDuration(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
             // duration block should end after exact duration, with gap
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
-            playoutItems.Last().FinishOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
+            playoutItems.Last().FinishOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
             playoutBuilderState.DurationFinish.IsNone.Should().BeTrue();
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
             
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
             playoutItems[0].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
             playoutItems[1].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
             playoutItems[2].GuideFinish.HasValue.Should().BeTrue();
@@ -291,6 +315,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -299,15 +327,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionTwo.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerDuration(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.FallbackFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -315,7 +345,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
             
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -323,25 +353,25 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(4);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
             playoutItems[0].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
             playoutItems[1].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
             playoutItems[2].GuideFinish.HasValue.Should().BeTrue();
             
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Fallback);
             playoutItems[3].GuideFinish.HasValue.Should().BeFalse();
@@ -371,6 +401,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -379,15 +413,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionTwo.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerDuration(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.TailFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -395,7 +431,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
             
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -403,37 +439,37 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(6);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
             playoutItems[0].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
             playoutItems[1].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
             playoutItems[2].GuideFinish.HasValue.Should().BeTrue();
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
             playoutItems[3].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[4].MediaItemId.Should().Be(4);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Tail);
             playoutItems[3].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.Tail);
             playoutItems[3].GuideFinish.HasValue.Should().BeFalse();
@@ -463,6 +499,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -471,23 +511,25 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionTwo.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerDuration(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.TailFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
-            playoutItems.Last().FinishOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
+            playoutItems.Last().FinishOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
             playoutBuilderState.DurationFinish.IsNone.Should().BeTrue();
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
             
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -495,37 +537,37 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(6);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
             playoutItems[0].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
             playoutItems[1].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
             playoutItems[2].GuideFinish.HasValue.Should().BeTrue();
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
             playoutItems[3].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[4].MediaItemId.Should().Be(4);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Tail);
             playoutItems[4].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.Tail);
             playoutItems[5].GuideFinish.HasValue.Should().BeFalse();
@@ -562,6 +604,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -574,9 +620,11 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionThree.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerDuration(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(
                     scheduleItem,
                     enumerator1,
@@ -586,9 +634,9 @@ namespace ErsatzTV.Core.Tests.Scheduling
                     enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -596,7 +644,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
             
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -605,43 +653,43 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(7);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
             playoutItems[0].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
             playoutItems[1].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
             playoutItems[2].GuideFinish.HasValue.Should().BeTrue();
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
             playoutItems[3].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[4].MediaItemId.Should().Be(4);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Tail);
             playoutItems[4].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.Tail);
             playoutItems[5].GuideFinish.HasValue.Should().BeFalse();
 
             playoutItems[6].MediaItemId.Should().Be(5);
-            playoutItems[6].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
+            playoutItems[6].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
             playoutItems[6].GuideGroup.Should().Be(3);
             playoutItems[6].FillerKind.Should().Be(FillerKind.Fallback);
             playoutItems[6].GuideFinish.HasValue.Should().BeFalse();

ErsatzTV.Core.Tests/Scheduling/PlayoutModeSchedulerFloodTests.cs

@@ -41,15 +41,21 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 NextScheduleItem
             };
             
-            var scheduler = new PlayoutModeSchedulerFlood(sortedScheduleItems, new Mock<ILogger>().Object);
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                sortedScheduleItems,
+                new CollectionEnumeratorState());
+            
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
+            var scheduler = new PlayoutModeSchedulerFlood(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -57,24 +63,24 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(1);
 
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.AddHours(2));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.AddHours(2));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
         }
@@ -110,15 +116,21 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
-            var scheduler = new PlayoutModeSchedulerFlood(sortedScheduleItems, new Mock<ILogger>().Object);
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                sortedScheduleItems,
+                new CollectionEnumeratorState());
+            
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
+            var scheduler = new PlayoutModeSchedulerFlood(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -126,24 +138,24 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(1);
 
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.AddHours(2));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.AddHours(2));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
         }
@@ -188,15 +200,21 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 NextScheduleItem
             };
 
-            var scheduler = new PlayoutModeSchedulerFlood(sortedScheduleItems, new Mock<ILogger>().Object);
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                sortedScheduleItems,
+                new CollectionEnumeratorState());
+            
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
+            var scheduler = new PlayoutModeSchedulerFlood(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.PostRollFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -204,7 +222,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(1);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -212,32 +230,32 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(6);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(3);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(1);
             playoutItems[1].FillerKind.Should().Be(FillerKind.PostRoll);
 
             playoutItems[2].MediaItemId.Should().Be(2);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems[2].GuideGroup.Should().Be(2);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[3].MediaItemId.Should().Be(4);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 55, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 55, 0)));
             playoutItems[3].GuideGroup.Should().Be(2);
             playoutItems[3].FillerKind.Should().Be(FillerKind.PostRoll);
 
             playoutItems[4].MediaItemId.Should().Be(1);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.AddHours(2));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.AddHours(2));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.PostRoll);
         }
@@ -269,15 +287,21 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 NextScheduleItem
             };
             
-            var scheduler = new PlayoutModeSchedulerFlood(sortedScheduleItems, new Mock<ILogger>().Object);
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                sortedScheduleItems,
+                new CollectionEnumeratorState());
+            
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
+            var scheduler = new PlayoutModeSchedulerFlood(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -285,24 +309,24 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(1);
 
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
         }
@@ -344,15 +368,21 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 NextScheduleItem
             };
             
-            var scheduler = new PlayoutModeSchedulerFlood(sortedScheduleItems, new Mock<ILogger>().Object);
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                sortedScheduleItems,
+                new CollectionEnumeratorState());
+            
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
+            var scheduler = new PlayoutModeSchedulerFlood(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.TailFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -360,7 +390,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(1);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -368,32 +398,32 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(6);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[4].MediaItemId.Should().Be(4);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.Tail);
         }
@@ -435,15 +465,21 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 NextScheduleItem
             };
             
-            var scheduler = new PlayoutModeSchedulerFlood(sortedScheduleItems, new Mock<ILogger>().Object);
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                sortedScheduleItems,
+                new CollectionEnumeratorState());
+            
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
+            var scheduler = new PlayoutModeSchedulerFlood(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.FallbackFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -451,7 +487,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(1);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -459,22 +495,22 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(4);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Fallback);
         }
@@ -516,15 +552,21 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 NextScheduleItem
             };
             
-            var scheduler = new PlayoutModeSchedulerFlood(sortedScheduleItems, new Mock<ILogger>().Object);
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                sortedScheduleItems,
+                new CollectionEnumeratorState());
+            
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
+            var scheduler = new PlayoutModeSchedulerFlood(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.TailFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -532,7 +574,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(1);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -540,32 +582,32 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(6);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[4].MediaItemId.Should().Be(4);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.Tail);
         }
@@ -617,9 +659,15 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 NextScheduleItem
             };
             
-            var scheduler = new PlayoutModeSchedulerFlood(sortedScheduleItems, new Mock<ILogger>().Object);
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                sortedScheduleItems,
+                new CollectionEnumeratorState());
+
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
+            var scheduler = new PlayoutModeSchedulerFlood(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(
                     scheduleItem,
                     enumerator1,
@@ -629,9 +677,9 @@ namespace ErsatzTV.Core.Tests.Scheduling
                     enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -639,7 +687,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(1);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -648,37 +696,37 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(7);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[4].MediaItemId.Should().Be(4);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[6].MediaItemId.Should().Be(5);
-            playoutItems[6].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
+            playoutItems[6].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
             playoutItems[6].GuideGroup.Should().Be(3);
             playoutItems[6].FillerKind.Should().Be(FillerKind.Fallback);
         }
@@ -730,9 +778,15 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 NextScheduleItem
             };
             
-            var scheduler = new PlayoutModeSchedulerFlood(sortedScheduleItems, new Mock<ILogger>().Object);
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                sortedScheduleItems,
+                new CollectionEnumeratorState());
+
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
+            var scheduler = new PlayoutModeSchedulerFlood(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(
                     scheduleItem,
                     enumerator1,
@@ -742,9 +796,9 @@ namespace ErsatzTV.Core.Tests.Scheduling
                     enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -752,7 +806,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(1);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(0);
@@ -761,17 +815,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.AddHours(2));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.AddHours(2));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
         }

ErsatzTV.Core.Tests/Scheduling/PlayoutModeSchedulerMultipleTests.cs

@@ -34,6 +34,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Count = 3
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -43,15 +47,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 { CollectionKey.ForScheduleItem(scheduleItem), collectionOne.MediaItems }
             }.ToMap();
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerMultiple(collectionMediaItems, new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -59,24 +65,24 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.AddHours(2));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.AddHours(2));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
         }
@@ -99,6 +105,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Count = 3
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -108,15 +118,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 { CollectionKey.ForScheduleItem(scheduleItem), collectionOne.MediaItems }
             }.ToMap();
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerMultiple(collectionMediaItems, new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -124,24 +136,24 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
         }
@@ -170,6 +182,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Count = 3
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -184,15 +200,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 { CollectionKey.ForFillerPreset(scheduleItem.TailFiller), collectionTwo.MediaItems }
             }.ToMap();
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerMultiple(collectionMediaItems, new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.TailFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -200,7 +218,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -208,32 +226,32 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(6);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[4].MediaItemId.Should().Be(4);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.Tail);
         }
@@ -262,6 +280,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Count = 3
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -276,15 +298,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 { CollectionKey.ForFillerPreset(scheduleItem.FallbackFiller), collectionTwo.MediaItems }
             }.ToMap();
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerMultiple(collectionMediaItems, new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.FallbackFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -292,7 +316,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -300,22 +324,22 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(4);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Fallback);
         }
@@ -344,6 +368,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Count = 3
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -358,15 +386,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 { CollectionKey.ForFillerPreset(scheduleItem.TailFiller), collectionTwo.MediaItems }
             }.ToMap();
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerMultiple(collectionMediaItems, new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.TailFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -374,7 +404,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -382,32 +412,32 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(6);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
             
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[4].MediaItemId.Should().Be(4);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Tail);
         
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.Tail);
         }
@@ -442,6 +472,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Count = 3
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -461,9 +495,11 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 { CollectionKey.ForFillerPreset(scheduleItem.FallbackFiller), collectionThree.MediaItems }
             }.ToMap();
 
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerMultiple(collectionMediaItems, new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(
                     scheduleItem,
                     enumerator1,
@@ -473,9 +509,9 @@ namespace ErsatzTV.Core.Tests.Scheduling
                     enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -483,7 +519,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -492,37 +528,37 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(7);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddMinutes(55));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddMinutes(55));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
         
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(1, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
             
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[3].GuideGroup.Should().Be(3);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[4].MediaItemId.Should().Be(4);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
             playoutItems[4].GuideGroup.Should().Be(3);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Tail);
         
             playoutItems[5].MediaItemId.Should().Be(3);
-            playoutItems[5].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
+            playoutItems[5].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
             playoutItems[5].GuideGroup.Should().Be(3);
             playoutItems[5].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[6].MediaItemId.Should().Be(5);
-            playoutItems[6].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
+            playoutItems[6].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
             playoutItems[6].GuideGroup.Should().Be(3);
             playoutItems[6].FillerKind.Should().Be(FillerKind.Fallback);
         }
@@ -557,6 +593,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 Count = 3
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -576,9 +616,11 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 { CollectionKey.ForFillerPreset(scheduleItem.FallbackFiller), collectionThree.MediaItems }
             }.ToMap();
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerMultiple(collectionMediaItems, new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(
                     scheduleItem,
                     enumerator1,
@@ -588,9 +630,9 @@ namespace ErsatzTV.Core.Tests.Scheduling
                     enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(4);
@@ -598,7 +640,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(0);
@@ -607,17 +649,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(3);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(2);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems[1].GuideGroup.Should().Be(2);
             playoutItems[1].FillerKind.Should().Be(FillerKind.None);
         
             playoutItems[2].MediaItemId.Should().Be(1);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.AddHours(2));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.AddHours(2));
             playoutItems[2].GuideGroup.Should().Be(3);
             playoutItems[2].FillerKind.Should().Be(FillerKind.None);
         }

ErsatzTV.Core.Tests/Scheduling/PlayoutModeSchedulerOneTests.cs

@@ -31,19 +31,25 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 FallbackFiller = null
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerOne(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -51,14 +57,14 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator.State.Index.Should().Be(1);
 
             playoutItems.Count.Should().Be(1);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
         }
@@ -92,6 +98,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -104,15 +114,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionThree.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerOne(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.TailFiller, enumerator2, scheduleItem.FallbackFiller, enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -120,7 +132,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(0);
@@ -129,7 +141,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(1);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
         }
@@ -157,6 +169,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 FallbackFiller = null
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -165,15 +181,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionTwo.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerOne(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.TailFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -181,7 +199,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -189,22 +207,22 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(4);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(3);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[1].GuideGroup.Should().Be(1);
             playoutItems[1].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[2].MediaItemId.Should().Be(4);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(1);
             playoutItems[2].FillerKind.Should().Be(FillerKind.Tail);
         
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
             playoutItems[3].GuideGroup.Should().Be(1);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
         }
@@ -232,6 +250,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -240,15 +262,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionTwo.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerOne(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.FallbackFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -256,7 +280,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -264,12 +288,12 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(2);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(3);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.AddHours(1));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.AddHours(1));
             playoutItems[1].GuideGroup.Should().Be(1);
             playoutItems[1].FillerKind.Should().Be(FillerKind.Fallback);
         }
@@ -297,6 +321,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 FallbackFiller = null
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -305,15 +333,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionTwo.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerOne(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.TailFiller, enumerator2),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -321,7 +351,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -329,22 +359,22 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(4);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(3);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[1].GuideGroup.Should().Be(1);
             playoutItems[1].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[2].MediaItemId.Should().Be(4);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
             playoutItems[2].GuideGroup.Should().Be(1);
             playoutItems[2].FillerKind.Should().Be(FillerKind.Tail);
         
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
             playoutItems[3].GuideGroup.Should().Be(1);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
         }
@@ -378,6 +408,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -390,9 +424,11 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionThree.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerOne(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(
                     scheduleItem,
                     enumerator1,
@@ -402,9 +438,9 @@ namespace ErsatzTV.Core.Tests.Scheduling
                     enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -412,7 +448,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -421,27 +457,27 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(5);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(3);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[1].GuideGroup.Should().Be(1);
             playoutItems[1].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[2].MediaItemId.Should().Be(4);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 49, 0)));
             playoutItems[2].GuideGroup.Should().Be(1);
             playoutItems[2].FillerKind.Should().Be(FillerKind.Tail);
         
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 53, 0)));
             playoutItems[3].GuideGroup.Should().Be(1);
             playoutItems[3].FillerKind.Should().Be(FillerKind.Tail);
 
             playoutItems[4].MediaItemId.Should().Be(5);
-            playoutItems[4].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
+            playoutItems[4].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 57, 0)));
             playoutItems[4].GuideGroup.Should().Be(1);
             playoutItems[4].FillerKind.Should().Be(FillerKind.Fallback);
         }
@@ -475,6 +511,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -487,9 +527,11 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionThree.MediaItems,
                 new CollectionEnumeratorState());
             
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerOne(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(
                     scheduleItem,
                     enumerator1,
@@ -499,9 +541,9 @@ namespace ErsatzTV.Core.Tests.Scheduling
                     enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -509,7 +551,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(0);
@@ -518,7 +560,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(1);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
         }
@@ -554,6 +596,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -566,15 +612,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionThree.MediaItems,
                 new CollectionEnumeratorState());
 
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerOne(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.PostRollFiller, enumerator2, scheduleItem.FallbackFiller, enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -582,7 +630,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -590,22 +638,22 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(4);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(3);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[1].GuideGroup.Should().Be(1);
             playoutItems[1].FillerKind.Should().Be(FillerKind.PostRoll);
 
             playoutItems[2].MediaItemId.Should().Be(4);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(1);
             playoutItems[2].FillerKind.Should().Be(FillerKind.PostRoll);
         
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
             playoutItems[3].GuideGroup.Should().Be(1);
             playoutItems[3].FillerKind.Should().Be(FillerKind.PostRoll);
         }
@@ -641,6 +689,10 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 }
             };
             
+            var scheduleItemsEnumerator = new OrderedScheduleItemsEnumerator(
+                new List<ProgramScheduleItem> { scheduleItem },
+                new CollectionEnumeratorState());
+
             var enumerator1 = new ChronologicalMediaCollectionEnumerator(
                 collectionOne.MediaItems,
                 new CollectionEnumeratorState());
@@ -653,15 +705,17 @@ namespace ErsatzTV.Core.Tests.Scheduling
                 collectionThree.MediaItems,
                 new CollectionEnumeratorState());
 
+            PlayoutBuilderState startState = StartState(scheduleItemsEnumerator);
+
             var scheduler = new PlayoutModeSchedulerOne(new Mock<ILogger>().Object);
             (PlayoutBuilderState playoutBuilderState, List<PlayoutItem> playoutItems) = scheduler.Schedule(
-                StartState,
+                startState,
                 CollectionEnumerators(scheduleItem, enumerator1, scheduleItem.PostRollFiller, enumerator2, scheduleItem.FallbackFiller, enumerator3),
                 scheduleItem,
                 NextScheduleItem,
-                HardStop);
+                HardStop(scheduleItemsEnumerator));
 
-            playoutBuilderState.CurrentTime.Should().Be(StartState.CurrentTime.AddHours(3));
+            playoutBuilderState.CurrentTime.Should().Be(startState.CurrentTime.AddHours(3));
             playoutItems.Last().FinishOffset.Should().Be(playoutBuilderState.CurrentTime);
 
             playoutBuilderState.NextGuideGroup.Should().Be(2);
@@ -669,7 +723,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutBuilderState.InFlood.Should().BeFalse();
             playoutBuilderState.MultipleRemaining.IsNone.Should().BeTrue();
             playoutBuilderState.InDurationFiller.Should().BeFalse();
-            playoutBuilderState.ScheduleItemIndex.Should().Be(1);
+            playoutBuilderState.ScheduleItemsEnumerator.State.Index.Should().Be(0);
 
             enumerator1.State.Index.Should().Be(1);
             enumerator2.State.Index.Should().Be(1);
@@ -678,22 +732,22 @@ namespace ErsatzTV.Core.Tests.Scheduling
             playoutItems.Count.Should().Be(4);
 
             playoutItems[0].MediaItemId.Should().Be(1);
-            playoutItems[0].StartOffset.Should().Be(StartState.CurrentTime);
+            playoutItems[0].StartOffset.Should().Be(startState.CurrentTime);
             playoutItems[0].GuideGroup.Should().Be(1);
             playoutItems[0].FillerKind.Should().Be(FillerKind.None);
 
             playoutItems[1].MediaItemId.Should().Be(3);
-            playoutItems[1].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
+            playoutItems[1].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 45, 0)));
             playoutItems[1].GuideGroup.Should().Be(1);
             playoutItems[1].FillerKind.Should().Be(FillerKind.PostRoll);
 
             playoutItems[2].MediaItemId.Should().Be(4);
-            playoutItems[2].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
+            playoutItems[2].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 50, 0)));
             playoutItems[2].GuideGroup.Should().Be(1);
             playoutItems[2].FillerKind.Should().Be(FillerKind.PostRoll);
         
             playoutItems[3].MediaItemId.Should().Be(3);
-            playoutItems[3].StartOffset.Should().Be(StartState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
+            playoutItems[3].StartOffset.Should().Be(startState.CurrentTime.Add(new TimeSpan(2, 55, 0)));
             playoutItems[3].GuideGroup.Should().Be(1);
             playoutItems[3].FillerKind.Should().Be(FillerKind.PostRoll);
         }

ErsatzTV.Core.Tests/Scheduling/SchedulerTestBase.cs

@@ -10,8 +10,8 @@ namespace ErsatzTV.Core.Tests.Scheduling
 {
     public abstract class SchedulerTestBase
     {
-        protected static PlayoutBuilderState StartState => new(
-            0,
+        protected static PlayoutBuilderState StartState(IScheduleItemsEnumerator scheduleItemsEnumerator) => new(
+            scheduleItemsEnumerator,
             Prelude.None,
             Prelude.None,
             false,
@@ -24,7 +24,8 @@ namespace ErsatzTV.Core.Tests.Scheduling
             StartTime = null
         };
 
-        protected static DateTimeOffset HardStop => StartState.CurrentTime.AddHours(6);
+        protected static DateTimeOffset HardStop(IScheduleItemsEnumerator scheduleItemsEnumerator) =>
+            StartState(scheduleItemsEnumerator).CurrentTime.AddHours(6);
 
         protected static Dictionary<CollectionKey, IMediaCollectionEnumerator> CollectionEnumerators(
             ProgramScheduleItem scheduleItem, IMediaCollectionEnumerator enumerator) =>

ErsatzTV.Core/Domain/PlayoutAnchor.cs

@@ -6,10 +6,7 @@ namespace ErsatzTV.Core.Domain
 {
     public class PlayoutAnchor
     {
-        public int NextScheduleItemId { get; set; }
-
-        public ProgramScheduleItem NextScheduleItem { get; set; }
-
+        public CollectionEnumeratorState ScheduleItemsEnumeratorState { get; set; }
         public DateTime NextStart { get; set; }
         public int? MultipleRemaining { get; set; }
         public DateTime? DurationFinish { get; set; }

ErsatzTV.Core/Domain/ProgramSchedule.cs

@@ -8,6 +8,7 @@ namespace ErsatzTV.Core.Domain
         public string Name { get; set; }
         public bool KeepMultiPartEpisodesTogether { get; set; }
         public bool TreatCollectionsAsShows { get; set; }
+        public bool ShuffleScheduleItems { get; set; }
         public List<ProgramScheduleItem> Items { get; set; }
         public List<Playout> Playouts { get; set; }
     }

ErsatzTV.Core/Interfaces/Scheduling/IScheduleItemsEnumerator.cs

@@ -0,0 +1,12 @@
+using ErsatzTV.Core.Domain;
+using LanguageExt;
+
+namespace ErsatzTV.Core.Interfaces.Scheduling;
+
+public interface IScheduleItemsEnumerator
+{
+    CollectionEnumeratorState State { get; }
+    ProgramScheduleItem Current { get; }
+    void MoveNext();
+    ProgramScheduleItem Peek(int offset);
+}

ErsatzTV.Core/Scheduling/OrderedScheduleItemsEnumerator.cs

@@ -0,0 +1,40 @@
+using System.Collections.Generic;
+using System.Linq;
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Scheduling;
+
+namespace ErsatzTV.Core.Scheduling;
+
+public class OrderedScheduleItemsEnumerator : IScheduleItemsEnumerator
+{
+    private readonly IList<ProgramScheduleItem> _sortedScheduleItems;
+
+    public OrderedScheduleItemsEnumerator(
+        IEnumerable<ProgramScheduleItem> scheduleItems,
+        CollectionEnumeratorState state)
+    {
+        _sortedScheduleItems = scheduleItems.OrderBy(i => i.Index).ToList();
+
+        State = new CollectionEnumeratorState { Seed = state.Seed };
+
+        if (state.Index >= _sortedScheduleItems.Count)
+        {
+            state.Index = 0;
+            state.Seed = 0;
+        }
+
+        while (State.Index < state.Index)
+        {
+            MoveNext();
+        }
+    }
+
+    public CollectionEnumeratorState State { get; }
+
+    public ProgramScheduleItem Current => _sortedScheduleItems[State.Index];
+
+    public void MoveNext() => State.Index = (State.Index + 1) % _sortedScheduleItems.Count;
+
+    public ProgramScheduleItem Peek(int offset) =>
+        _sortedScheduleItems[(State.Index + offset) % _sortedScheduleItems.Count];
+}

ErsatzTV.Core/Scheduling/PlayoutBuilder.cs

@@ -3,7 +3,6 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using ErsatzTV.Core.Domain;
-using ErsatzTV.Core.Extensions;
 using ErsatzTV.Core.Interfaces.Repositories;
 using ErsatzTV.Core.Interfaces.Scheduling;
 using LanguageExt;
@@ -105,6 +104,12 @@ namespace ErsatzTV.Core.Scheduling
             }
 
             var sortedScheduleItems = playout.ProgramSchedule.Items.OrderBy(i => i.Index).ToList();
+            CollectionEnumeratorState scheduleItemsEnumeratorState =
+                playout.Anchor?.ScheduleItemsEnumeratorState ?? new CollectionEnumeratorState
+                    { Seed = Random.Next(), Index = 0 };
+            IScheduleItemsEnumerator scheduleItemsEnumerator = playout.ProgramSchedule.ShuffleScheduleItems
+                ? new ShuffledScheduleItemsEnumerator(playout.ProgramSchedule.Items, scheduleItemsEnumeratorState)
+                : new OrderedScheduleItemsEnumerator(playout.ProgramSchedule.Items, scheduleItemsEnumeratorState);
             var collectionEnumerators = new Dictionary<CollectionKey, IMediaCollectionEnumerator>();
             foreach ((CollectionKey collectionKey, List<MediaItem> mediaItems) in collectionMediaItems)
             {
@@ -119,7 +124,7 @@ namespace ErsatzTV.Core.Scheduling
             }
 
             // find start anchor
-            PlayoutAnchor startAnchor = FindStartAnchor(playout, playoutStart, sortedScheduleItems);
+            PlayoutAnchor startAnchor = FindStartAnchor(playout, playoutStart, scheduleItemsEnumerator);
 
             // start at the previously-decided time
             DateTimeOffset currentTime = startAnchor.NextStartOffset.ToLocalTime();
@@ -142,7 +147,7 @@ namespace ErsatzTV.Core.Scheduling
             // start with the previously-decided schedule item
             // start with the previous multiple/duration states
             var playoutBuilderState = new PlayoutBuilderState(
-                sortedScheduleItems.IndexOf(startAnchor.NextScheduleItem),
+                scheduleItemsEnumerator,
                 Optional(startAnchor.MultipleRemaining),
                 startAnchor.DurationFinishOffset,
                 startAnchor.InFlood,
@@ -153,17 +158,15 @@ namespace ErsatzTV.Core.Scheduling
             var schedulerOne = new PlayoutModeSchedulerOne(_logger);
             var schedulerMultiple = new PlayoutModeSchedulerMultiple(collectionMediaItems, _logger);
             var schedulerDuration = new PlayoutModeSchedulerDuration(_logger);
-            var schedulerFlood = new PlayoutModeSchedulerFlood(sortedScheduleItems, _logger);
+            var schedulerFlood = new PlayoutModeSchedulerFlood(_logger);
 
             // loop until we're done filling the desired amount of time
             while (playoutBuilderState.CurrentTime < playoutFinish)
             {
                 // get the schedule item out of the sorted list
-                ProgramScheduleItem scheduleItem =
-                    sortedScheduleItems[playoutBuilderState.ScheduleItemIndex % sortedScheduleItems.Count];
+                ProgramScheduleItem scheduleItem = playoutBuilderState.ScheduleItemsEnumerator.Current;
 
-                ProgramScheduleItem nextScheduleItem =
-                    sortedScheduleItems[(playoutBuilderState.ScheduleItemIndex + 1) % sortedScheduleItems.Count];
+                ProgramScheduleItem nextScheduleItem = playoutBuilderState.ScheduleItemsEnumerator.Peek(1);
 
                 Tuple<PlayoutBuilderState, List<PlayoutItem>> result = scheduleItem switch
                 {
@@ -205,8 +208,7 @@ namespace ErsatzTV.Core.Scheduling
             }
 
             // once more to get playout anchor
-            ProgramScheduleItem anchorScheduleItem =
-                sortedScheduleItems[playoutBuilderState.ScheduleItemIndex % sortedScheduleItems.Count];
+            ProgramScheduleItem anchorScheduleItem = playoutBuilderState.ScheduleItemsEnumerator.Current;
 
             // build program schedule anchors
             playout.ProgramScheduleAnchors = BuildProgramScheduleAnchors(playout, collectionEnumerators);
@@ -226,8 +228,7 @@ namespace ErsatzTV.Core.Scheduling
 
             playout.Anchor = new PlayoutAnchor
             {
-                NextScheduleItem = anchorScheduleItem,
-                NextScheduleItemId = anchorScheduleItem.Id,
+                ScheduleItemsEnumeratorState = playoutBuilderState.ScheduleItemsEnumerator.State,
                 NextStart = PlayoutModeSchedulerBase<ProgramScheduleItem>.GetStartTimeAfter(playoutBuilderState, anchorScheduleItem)
                     .UtcDateTime,
                 MultipleRemaining = playoutBuilderState.MultipleRemaining.IsSome
@@ -320,18 +321,17 @@ namespace ErsatzTV.Core.Scheduling
         private static PlayoutAnchor FindStartAnchor(
             Playout playout,
             DateTimeOffset start,
-            IReadOnlyCollection<ProgramScheduleItem> sortedScheduleItems) =>
+            IScheduleItemsEnumerator enumerator) =>
             Optional(playout.Anchor).IfNone(
                 () =>
                 {
-                    ProgramScheduleItem schedule = sortedScheduleItems.Head();
+                    ProgramScheduleItem schedule = enumerator.Current;
                     switch (schedule.StartType)
                     {
                         case StartType.Fixed:
                             return new PlayoutAnchor
                             {
-                                NextScheduleItem = schedule,
-                                NextScheduleItemId = schedule.Id,
+                                ScheduleItemsEnumeratorState = enumerator.State,
                                 NextStart = (start - start.TimeOfDay).UtcDateTime +
                                             schedule.StartTime.GetValueOrDefault()
                             };
@@ -339,8 +339,7 @@ namespace ErsatzTV.Core.Scheduling
                         default:
                             return new PlayoutAnchor
                             {
-                                NextScheduleItem = schedule,
-                                NextScheduleItemId = schedule.Id,
+                                ScheduleItemsEnumeratorState = enumerator.State,
                                 NextStart = (start - start.TimeOfDay).UtcDateTime
                             };
                     }

ErsatzTV.Core/Scheduling/PlayoutBuilderState.cs

@@ -1,10 +1,11 @@
 using System;
+using ErsatzTV.Core.Interfaces.Scheduling;
 using LanguageExt;
 
 namespace ErsatzTV.Core.Scheduling
 {
     public record PlayoutBuilderState(
-        int ScheduleItemIndex,
+        IScheduleItemsEnumerator ScheduleItemsEnumerator,
         Option<int> MultipleRemaining,
         Option<DateTimeOffset> DurationFinish,
         bool InFlood,

ErsatzTV.Core/Scheduling/PlayoutModeSchedulerDuration.cs

@@ -122,9 +122,10 @@ namespace ErsatzTV.Core.Scheduling
 
                     nextState = nextState with
                     {
-                        DurationFinish = None,
-                        ScheduleItemIndex = nextState.ScheduleItemIndex + 1
+                        DurationFinish = None
                     };
+
+                    nextState.ScheduleItemsEnumerator.MoveNext();
                 }
             }
 
@@ -133,9 +134,10 @@ namespace ErsatzTV.Core.Scheduling
             {
                 nextState = nextState with
                 {
-                    DurationFinish = None,
-                    ScheduleItemIndex = nextState.ScheduleItemIndex + 1
+                    DurationFinish = None
                 };
+
+                nextState.ScheduleItemsEnumerator.MoveNext();
             }
 
             if (playoutItems.Select(pi => pi.GuideGroup).Distinct().Count() != 1)

ErsatzTV.Core/Scheduling/PlayoutModeSchedulerFlood.cs

@@ -12,12 +12,9 @@ namespace ErsatzTV.Core.Scheduling
 {
     public class PlayoutModeSchedulerFlood : PlayoutModeSchedulerBase<ProgramScheduleItemFlood>
     {
-        private readonly List<ProgramScheduleItem> _sortedScheduleItems;
-
-        public PlayoutModeSchedulerFlood(List<ProgramScheduleItem> sortedScheduleItems, ILogger logger)
+        public PlayoutModeSchedulerFlood(ILogger logger)
             : base(logger)
         {
-            _sortedScheduleItems = sortedScheduleItems;
         }
 
         public override Tuple<PlayoutBuilderState, List<PlayoutItem>> Schedule(
@@ -35,8 +32,7 @@ namespace ErsatzTV.Core.Scheduling
             IMediaCollectionEnumerator contentEnumerator =
                 collectionEnumerators[CollectionKey.ForScheduleItem(scheduleItem)];
 
-            ProgramScheduleItem peekScheduleItem =
-                _sortedScheduleItems[(nextState.ScheduleItemIndex + 1) % _sortedScheduleItems.Count];
+            ProgramScheduleItem peekScheduleItem = nextScheduleItem;
 
             while (contentEnumerator.Current.IsSome && nextState.CurrentTime < hardStop && willFinishInTime)
             {
@@ -81,7 +77,7 @@ namespace ErsatzTV.Core.Scheduling
                 {
                     playoutItems.AddRange(
                         AddFiller(nextState, collectionEnumerators, scheduleItem, playoutItem, itemChapters));
-                    // LogScheduledItem(scheduleItem, mediaItem, itemStartTime);
+                    LogScheduledItem(scheduleItem, mediaItem, itemStartTime);
 
                     DateTimeOffset actualEndTime = playoutItems.Max(p => p.FinishOffset);
                     if (Math.Abs((itemEndTimeWithFiller - actualEndTime).TotalSeconds) > 1)
@@ -105,19 +101,19 @@ namespace ErsatzTV.Core.Scheduling
                 }
             }
 
-            // _logger.LogDebug(
-            //     "Advancing to next schedule item after playout mode {PlayoutMode}",
-            //     "Flood");
+            _logger.LogDebug(
+                "Advancing to next schedule item after playout mode {PlayoutMode}",
+                "Flood");
 
             nextState = nextState with
             {
-                ScheduleItemIndex = nextState.ScheduleItemIndex + 1,
                 InFlood = nextState.CurrentTime >= hardStop,
                 NextGuideGroup = nextState.DecrementGuideGroup
             };
 
-            ProgramScheduleItem peekItem =
-                _sortedScheduleItems[nextState.ScheduleItemIndex % _sortedScheduleItems.Count];
+            nextState.ScheduleItemsEnumerator.MoveNext();
+
+            ProgramScheduleItem peekItem = nextScheduleItem;
             DateTimeOffset peekItemStart = GetStartTimeAfter(nextState, peekItem);
 
             if (scheduleItem.TailFiller != null)

ErsatzTV.Core/Scheduling/PlayoutModeSchedulerMultiple.cs

@@ -97,10 +97,11 @@ namespace ErsatzTV.Core.Scheduling
 
                 nextState = nextState with
                 {
-                    ScheduleItemIndex = nextState.ScheduleItemIndex + 1,
                     MultipleRemaining = None,
                     NextGuideGroup = nextState.DecrementGuideGroup
                 };
+
+                nextState.ScheduleItemsEnumerator.MoveNext();
             }
             
             DateTimeOffset nextItemStart = GetStartTimeAfter(nextState, nextScheduleItem);

ErsatzTV.Core/Scheduling/PlayoutModeSchedulerOne.cs

@@ -67,10 +67,10 @@ namespace ErsatzTV.Core.Scheduling
 
                 PlayoutBuilderState nextState = playoutBuilderState with
                 {
-                    CurrentTime = itemEndTimeWithFiller,
-                    ScheduleItemIndex = playoutBuilderState.ScheduleItemIndex + 1
+                    CurrentTime = itemEndTimeWithFiller
                 };
 
+                nextState.ScheduleItemsEnumerator.MoveNext();
                 contentEnumerator.MoveNext();
 
                 // LogScheduledItem(scheduleItem, mediaItem, itemStartTime);

ErsatzTV.Core/Scheduling/ShuffledScheduleItemsEnumerator.cs

@@ -0,0 +1,107 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Scheduling;
+
+namespace ErsatzTV.Core.Scheduling;
+
+public class ShuffledScheduleItemsEnumerator : IScheduleItemsEnumerator
+{
+    private readonly int _scheduleItemsCount;
+    private readonly IList<ProgramScheduleItem> _scheduleItems;
+    private CloneableRandom _random;
+    private IList<ProgramScheduleItem> _shuffled;
+
+    public ShuffledScheduleItemsEnumerator(
+        IList<ProgramScheduleItem> scheduleItems,
+        CollectionEnumeratorState state)
+    {
+        _scheduleItemsCount = scheduleItems.Count;
+        _scheduleItems = scheduleItems;
+
+        if (state.Index >= _scheduleItems.Count)
+        {
+            state.Index = 0;
+            state.Seed = new Random(state.Seed).Next();
+        }
+
+        _random = new CloneableRandom(state.Seed);
+        _shuffled = Shuffle(_scheduleItems, _random);
+
+        State = new CollectionEnumeratorState { Seed = state.Seed };
+        while (State.Index < state.Index)
+        {
+            MoveNext();
+        }
+    }
+
+    public CollectionEnumeratorState State { get; }
+
+    public ProgramScheduleItem Current => _shuffled[State.Index % _scheduleItemsCount];
+
+    public void MoveNext()
+    {
+        if ((State.Index + 1) % _scheduleItemsCount == 0)
+        {
+            ProgramScheduleItem tail = Current;
+
+            State.Index = 0;
+            do
+            {
+                State.Seed = _random.Next();
+                _random = new CloneableRandom(State.Seed);
+                _shuffled = Shuffle(_scheduleItems, _random);
+            } while (_scheduleItems.Count > 1 && Current == tail);
+        }
+        else
+        {
+            State.Index++;
+        }
+
+        State.Index %= _scheduleItemsCount;
+    }
+
+    public ProgramScheduleItem Peek(int offset)
+    {
+        if (offset == 0)
+        {
+            return Current;
+        }
+
+        if ((State.Index + offset) % _scheduleItemsCount == 0)
+        {
+            IList<ProgramScheduleItem> shuffled;
+            ProgramScheduleItem tail = Current;
+
+            // clone the random
+            CloneableRandom randomCopy = _random.Clone();
+
+            do
+            {
+                int newSeed = randomCopy.Next();
+                randomCopy = new CloneableRandom(newSeed);
+                shuffled = Shuffle(_scheduleItems, randomCopy);
+            } while (_scheduleItems.Count > 1 && shuffled[0] == tail);
+
+            return shuffled[0];
+        }
+
+        return _shuffled[(State.Index + offset) % _scheduleItemsCount];
+    }
+
+    private IList<ProgramScheduleItem> Shuffle(IEnumerable<ProgramScheduleItem> list, CloneableRandom random)
+    {
+        ProgramScheduleItem[] 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;
+    }
+}

ErsatzTV.Infrastructure/Data/Configurations/PlayoutConfiguration.cs

@@ -16,7 +16,9 @@ namespace ErsatzTV.Infrastructure.Data.Configurations
                 .OnDelete(DeleteBehavior.Cascade);
 
             builder.OwnsOne(p => p.Anchor)
-                .ToTable("PlayoutAnchor");
+                .ToTable("PlayoutAnchor")
+                .OwnsOne(a => a.ScheduleItemsEnumeratorState)
+                .ToTable("ScheduleItemsEnumeratorState");
 
             builder.HasMany(p => p.ProgramScheduleAnchors)
                 .WithOne(a => a.Playout)

ErsatzTV.Infrastructure/Migrations/20220223000405_Add_ProgramScheduleShuffleScheduleItems.cs

@@ -0,0 +1,26 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ErsatzTV.Infrastructure.Migrations
+{
+    public partial class Add_ProgramScheduleShuffleScheduleItems : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<bool>(
+                name: "ShuffleScheduleItems",
+                table: "ProgramSchedule",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: false);
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "ShuffleScheduleItems",
+                table: "ProgramSchedule");
+        }
+    }
+}

ErsatzTV.Infrastructure/Migrations/20220223020421_Add_PlayoutAnchorScheduleItemsEnumeratorState.cs

@@ -0,0 +1,69 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ErsatzTV.Infrastructure.Migrations
+{
+    public partial class Add_PlayoutAnchorScheduleItemsEnumeratorState : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_PlayoutAnchor_ProgramScheduleItem_NextScheduleItemId",
+                table: "PlayoutAnchor");
+
+            migrationBuilder.DropIndex(
+                name: "IX_PlayoutAnchor_NextScheduleItemId",
+                table: "PlayoutAnchor");
+
+            migrationBuilder.DropColumn(
+                name: "NextScheduleItemId",
+                table: "PlayoutAnchor");
+
+            migrationBuilder.CreateTable(
+                name: "ScheduleItemsEnumeratorState",
+                columns: table => new
+                {
+                    PlayoutAnchorPlayoutId = table.Column<int>(type: "INTEGER", nullable: false),
+                    Seed = table.Column<int>(type: "INTEGER", nullable: false),
+                    Index = table.Column<int>(type: "INTEGER", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_ScheduleItemsEnumeratorState", x => x.PlayoutAnchorPlayoutId);
+                    table.ForeignKey(
+                        name: "FK_ScheduleItemsEnumeratorState_PlayoutAnchor_PlayoutAnchorPlayoutId",
+                        column: x => x.PlayoutAnchorPlayoutId,
+                        principalTable: "PlayoutAnchor",
+                        principalColumn: "PlayoutId",
+                        onDelete: ReferentialAction.Cascade);
+                });
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "ScheduleItemsEnumeratorState");
+
+            migrationBuilder.AddColumn<int>(
+                name: "NextScheduleItemId",
+                table: "PlayoutAnchor",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: 0);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_PlayoutAnchor_NextScheduleItemId",
+                table: "PlayoutAnchor",
+                column: "NextScheduleItemId");
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_PlayoutAnchor_ProgramScheduleItem_NextScheduleItemId",
+                table: "PlayoutAnchor",
+                column: "NextScheduleItemId",
+                principalTable: "ProgramScheduleItem",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Cascade);
+        }
+    }
+}

ErsatzTV.Infrastructure/Migrations/20220223031713_Rebuild_AllPlayouts20220222.cs

@@ -0,0 +1,20 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ErsatzTV.Infrastructure.Migrations
+{
+    public partial class Rebuild_AllPlayouts20220222 : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql(@"DELETE FROM PlayoutItem");
+            migrationBuilder.Sql(@"DELETE FROM PlayoutProgramScheduleAnchor");
+            migrationBuilder.Sql(@"DELETE FROM PlayoutAnchor");
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+        }
+    }
+}

ErsatzTV.Infrastructure/Migrations/TvContextModelSnapshot.cs

@@ -1438,6 +1438,9 @@ namespace ErsatzTV.Infrastructure.Migrations
                     b.Property<string>("Name")
                         .HasColumnType("TEXT");
 
+                    b.Property<bool>("ShuffleScheduleItems")
+                        .HasColumnType("INTEGER");
+
                     b.Property<bool>("TreatCollectionsAsShows")
                         .HasColumnType("INTEGER");
 
@@ -2877,28 +2880,36 @@ namespace ErsatzTV.Infrastructure.Migrations
                             b1.Property<int>("NextGuideGroup")
                                 .HasColumnType("INTEGER");
 
-                            b1.Property<int>("NextScheduleItemId")
-                                .HasColumnType("INTEGER");
-
                             b1.Property<DateTime>("NextStart")
                                 .HasColumnType("TEXT");
 
                             b1.HasKey("PlayoutId");
 
-                            b1.HasIndex("NextScheduleItemId");
-
                             b1.ToTable("PlayoutAnchor", (string)null);
 
-                            b1.HasOne("ErsatzTV.Core.Domain.ProgramScheduleItem", "NextScheduleItem")
-                                .WithMany()
-                                .HasForeignKey("NextScheduleItemId")
-                                .OnDelete(DeleteBehavior.Cascade)
-                                .IsRequired();
-
                             b1.WithOwner()
                                 .HasForeignKey("PlayoutId");
 
-                            b1.Navigation("NextScheduleItem");
+                            b1.OwnsOne("ErsatzTV.Core.Domain.CollectionEnumeratorState", "ScheduleItemsEnumeratorState", b2 =>
+                                {
+                                    b2.Property<int>("PlayoutAnchorPlayoutId")
+                                        .HasColumnType("INTEGER");
+
+                                    b2.Property<int>("Index")
+                                        .HasColumnType("INTEGER");
+
+                                    b2.Property<int>("Seed")
+                                        .HasColumnType("INTEGER");
+
+                                    b2.HasKey("PlayoutAnchorPlayoutId");
+
+                                    b2.ToTable("ScheduleItemsEnumeratorState", (string)null);
+
+                                    b2.WithOwner()
+                                        .HasForeignKey("PlayoutAnchorPlayoutId");
+                                });
+
+                            b1.Navigation("ScheduleItemsEnumeratorState");
                         });
 
                     b.Navigation("Anchor");

ErsatzTV/Pages/ScheduleEditor.razor

@@ -31,6 +31,13 @@
                                          For="@(() => _model.TreatCollectionsAsShows)"/>
                         </MudTooltip>
                     </MudElement>
+                    <MudElement HtmlTag="div" Class="mt-3">
+                        <MudTooltip Text="Note: this disables fixed start times and flood mode">
+                            <MudCheckBox Label="Shuffle Schedule Items"
+                                         @bind-Checked="@_model.ShuffleScheduleItems"
+                                         For="@(() => _model.ShuffleScheduleItems)"/>
+                        </MudTooltip>
+                    </MudElement>
                 </MudCardContent>
                 <MudCardActions>
                     <MudButton ButtonType="ButtonType.Submit" Variant="Variant.Filled" Color="Color.Primary">
@@ -61,6 +68,7 @@
                 {
                     _model.Id = viewModel.Id;
                     _model.Name = viewModel.Name;
+                    _model.ShuffleScheduleItems = viewModel.ShuffleScheduleItems;
                     _model.KeepMultiPartEpisodesTogether = viewModel.KeepMultiPartEpisodesTogether;
                     _model.TreatCollectionsAsShows = viewModel.TreatCollectionsAsShows;
                 },

ErsatzTV/Pages/ScheduleItemsEditor.razor

@@ -57,16 +57,22 @@
                 </MudText>
             </MudTd>
             <MudTd>
+                @if (!_schedule.ShuffleScheduleItems)
+                {
                     <MudIconButton Icon="@Icons.Material.Filled.ArrowUpward"
                                    OnClick="@(_ => MoveItemUp(context))"
-                               Disabled="@(_schedule.Items.All(x => x.Index >= context.Index))">
+                                   Disabled="@(_schedule.ShuffleScheduleItems || _schedule.Items.All(x => x.Index >= context.Index))">
                     </MudIconButton>
+                }
             </MudTd>
             <MudTd>
+                @if (!_schedule.ShuffleScheduleItems)
+                {
                     <MudIconButton Icon="@Icons.Material.Filled.ArrowDownward"
                                    OnClick="@(_ => MoveItemDown(context))"
-                               Disabled="@(_schedule.Items.All(x => x.Index <= context.Index))">
+                                   Disabled="@(_schedule.ShuffleScheduleItems || _schedule.Items.All(x => x.Index <= context.Index))">
                     </MudIconButton>
+                }
             </MudTd>
             <MudTd>
                 <MudIconButton Icon="@Icons.Material.Filled.Delete"
@@ -91,9 +97,10 @@
                     <MudCard>
                         <MudCardContent>
                             <MudSelect Label="Start Type" @bind-Value="_selectedItem.StartType" For="@(() => _selectedItem.StartType)">
-                                @foreach (StartType startType in Enum.GetValues<StartType>())
+                                <MudSelectItem Value="StartType.Dynamic">Dynamic</MudSelectItem>
+                                @if (!_schedule.ShuffleScheduleItems)
                                 {
-                                    <MudSelectItem Value="@startType">@startType</MudSelectItem>
+                                    <MudSelectItem Value="StartType.Fixed">Fixed</MudSelectItem>
                                 }
                             </MudSelect>
                             <MudTimePicker Class="mt-3" Label="Start Time" @bind-Time="@_selectedItem.StartTime" For="@(() => _selectedItem.StartTime)" Disabled="@(_selectedItem.StartType == StartType.Dynamic)"/>
@@ -197,10 +204,13 @@
                                 }
                             </MudSelect>
                             <MudSelect Class="mt-3" Label="Playout Mode" @bind-Value="@_selectedItem.PlayoutMode" For="@(() => _selectedItem.PlayoutMode)">
-                                @foreach (PlayoutMode playoutMode in Enum.GetValues<PlayoutMode>())
+                                @if (!_schedule.ShuffleScheduleItems)
                                 {
-                                    <MudSelectItem Value="@playoutMode">@playoutMode</MudSelectItem>
+                                    <MudSelectItem Value="PlayoutMode.Flood">Flood</MudSelectItem>
                                 }
+                                <MudSelectItem Value="PlayoutMode.One">One</MudSelectItem>
+                                <MudSelectItem Value="PlayoutMode.Multiple">Multiple</MudSelectItem>
+                                <MudSelectItem Value="PlayoutMode.Duration">Duration</MudSelectItem>
                             </MudSelect>
                             <MudTextField Class="mt-3" Label="Multiple Count" @bind-Value="@_selectedItem.MultipleCount" For="@(() => _selectedItem.MultipleCount)" Disabled="@(_selectedItem.PlayoutMode != PlayoutMode.Multiple)"/>
                             <MudTimePicker Class="mt-3" Label="Playout Duration" @bind-Time="@_selectedItem.PlayoutDuration" For="@(() => _selectedItem.PlayoutDuration)" Disabled="@(_selectedItem.PlayoutMode != PlayoutMode.Duration)"/>
@@ -315,8 +325,13 @@
             .Map(list => list.OrderBy(vm => vm.Name, StringComparer.CurrentCultureIgnoreCase).ToList());
 
         string name = string.Empty;
+        var shuffleScheduleItems = false;
         Option<ProgramScheduleViewModel> maybeSchedule = await _mediator.Send(new GetProgramScheduleById(Id));
-        maybeSchedule.IfSome(vm => name = vm.Name);
+        foreach (ProgramScheduleViewModel schedule in maybeSchedule)
+        {
+            name = schedule.Name;
+            shuffleScheduleItems = schedule.ShuffleScheduleItems;
+        }
 
         Option<IEnumerable<ProgramScheduleItemViewModel>> maybeResults = await _mediator.Send(new GetProgramScheduleItems(Id));
         foreach (IEnumerable<ProgramScheduleItemViewModel> items in maybeResults)
@@ -324,6 +339,7 @@
             _schedule = new ProgramScheduleItemsEditViewModel
             {
                 Name = name,
+                ShuffleScheduleItems = shuffleScheduleItems,
                 Items = items.Map(ProjectToEditViewModel).ToList()
             };
 

ErsatzTV/ViewModels/ProgramScheduleEditViewModel.cs

@@ -9,11 +9,12 @@ namespace ErsatzTV.ViewModels
         public string Name { get; set; }
         public bool KeepMultiPartEpisodesTogether { get; set; }
         public bool TreatCollectionsAsShows { get; set; }
+        public bool ShuffleScheduleItems { get; set; }
 
         public UpdateProgramSchedule ToUpdate() =>
-            new(Id, Name, KeepMultiPartEpisodesTogether, TreatCollectionsAsShows);
+            new(Id, Name, KeepMultiPartEpisodesTogether, TreatCollectionsAsShows, ShuffleScheduleItems);
 
         public CreateProgramSchedule ToCreate() =>
-            new(Name, KeepMultiPartEpisodesTogether, TreatCollectionsAsShows);
+            new(Name, KeepMultiPartEpisodesTogether, TreatCollectionsAsShows, ShuffleScheduleItems);
     }
 }

ErsatzTV/ViewModels/ProgramScheduleItemsEditViewModel.cs

@@ -5,6 +5,7 @@ namespace ErsatzTV.ViewModels
     public class ProgramScheduleItemsEditViewModel
     {
         public string Name { get; set; }
+        public bool ShuffleScheduleItems { get; set; }
         public List<ProgramScheduleItemEditViewModel> Items { get; set; }
     }
 }