From eee10dee22fc1252dd02815bb9ac8b6634441f54 Mon Sep 17 00:00:00 2001
From: Jason Dove <jason@jasondove.me>
Date: Mon, 31 May 2021 07:31:15 -0500
Subject: [PATCH] skip zero duration items when building playouts (#236)

---
 CHANGELOG.md                                  |  8 +++-
 .../Scheduling/PlayoutBuilderTests.cs         | 23 ++++++++++-
 ErsatzTV.Core/Scheduling/PlayoutBuilder.cs    | 39 ++++++++++++++++++-
 3 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8c9f83cb6..55d4bd0fe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,7 +3,13 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
-## Unreleased
+## [Unreleased]
+
+### Changed
+- Skip zero duration items when building a playout, rather than aborting the playout build
+
+### Fixed
+- Fix edge case where a playout rebuild would get stuck and block all other playouts and library scans
 
 ## [0.0.41-prealpha] - 2021-05-30
 ### Added
diff --git a/ErsatzTV.Core.Tests/Scheduling/PlayoutBuilderTests.cs b/ErsatzTV.Core.Tests/Scheduling/PlayoutBuilderTests.cs
index 4976fea10..431f677e7 100644
--- a/ErsatzTV.Core.Tests/Scheduling/PlayoutBuilderTests.cs
+++ b/ErsatzTV.Core.Tests/Scheduling/PlayoutBuilderTests.cs
@@ -39,7 +39,7 @@ namespace ErsatzTV.Core.Tests.Scheduling
 
         [Test]
         [Timeout(2000)]
-        public async Task ZeroDurationItem_Should_Abort()
+        public async Task OnlyZeroDurationItem_Should_Abort()
         {
             var mediaItems = new List<MediaItem>
             {
@@ -55,6 +55,27 @@ namespace ErsatzTV.Core.Tests.Scheduling
             result.Items.Should().BeNull();
         }
 
+        [Test]
+        public async Task ZeroDurationItem_Should_BeSkipped()
+        {
+            var mediaItems = new List<MediaItem>
+            {
+                TestMovie(1, TimeSpan.Zero, DateTime.Today),
+                TestMovie(2, TimeSpan.FromHours(6), DateTime.Today)
+            };
+
+            (PlayoutBuilder builder, Playout playout) = TestDataFloodForItems(mediaItems, PlaybackOrder.Random);
+            DateTimeOffset start = HoursAfterMidnight(0);
+            DateTimeOffset finish = start + TimeSpan.FromHours(6);
+
+            Playout result = await builder.BuildPlayoutItems(playout, start, finish);
+
+            result.Items.Count.Should().Be(1);
+            result.Items.Head().MediaItemId.Should().Be(2);
+            result.Items.Head().StartOffset.TimeOfDay.Should().Be(TimeSpan.Zero);
+            result.Items.Head().FinishOffset.TimeOfDay.Should().Be(TimeSpan.FromHours(6));
+        }
+
         [Test]
         public async Task InitialFlood_Should_StartAtMidnight()
         {
diff --git a/ErsatzTV.Core/Scheduling/PlayoutBuilder.cs b/ErsatzTV.Core/Scheduling/PlayoutBuilder.cs
index 3506d54a1..06358254f 100644
--- a/ErsatzTV.Core/Scheduling/PlayoutBuilder.cs
+++ b/ErsatzTV.Core/Scheduling/PlayoutBuilder.cs
@@ -80,17 +80,52 @@ namespace ErsatzTV.Core.Scheduling
                 playout.Channel.Number,
                 playout.Channel.Name);
 
+            foreach ((CollectionKey _, List<MediaItem> items) in collectionMediaItems)
+            {
+                var zeroItems = new List<MediaItem>();
+
+                foreach (MediaItem item in items)
+                {
+                    bool isZero = item switch
+                    {
+                        Movie m => await m.MediaVersions.Map(v => v.Duration).HeadOrNone().IfNoneAsync(TimeSpan.Zero) ==
+                                   TimeSpan.Zero,
+                        Episode e => await e.MediaVersions.Map(v => v.Duration).HeadOrNone()
+                                         .IfNoneAsync(TimeSpan.Zero) ==
+                                     TimeSpan.Zero,
+                        MusicVideo mv => await mv.MediaVersions.Map(v => v.Duration).HeadOrNone()
+                                             .IfNoneAsync(TimeSpan.Zero) ==
+                                         TimeSpan.Zero,
+                        _ => true
+                    };
+
+                    if (isZero)
+                    {
+                        _logger.LogWarning(
+                            "Skipping media item with zero duration {MediaItem} - {MediaItemTitle}",
+                            item.Id,
+                            DisplayTitle(item));
+
+                        zeroItems.Add(item);
+                    }
+                }
+
+                items.RemoveAll(i => zeroItems.Contains(i));
+            }
+
+            // this guard needs to be below the place where we modify the collections (by removing zero-duration items)
             Option<CollectionKey> emptyCollection =
                 collectionMediaItems.Find(c => !c.Value.Any()).Map(c => c.Key);
             if (emptyCollection.IsSome)
             {
                 _logger.LogError(
-                    "Unable to rebuild playout; collection {@CollectionKey} has no items!",
+                    "Unable to rebuild playout; collection {@CollectionKey} has no valid items!",
                     emptyCollection.ValueUnsafe());
 
                 return playout;
             }
 
+            // leaving this guard in for a while to ensure the zero item removal is working properly
             Option<CollectionKey> zeroDurationCollection = collectionMediaItems.Find(
                 c => c.Value.Any(
                     mi => mi switch
@@ -106,7 +141,7 @@ namespace ErsatzTV.Core.Scheduling
             if (zeroDurationCollection.IsSome)
             {
                 _logger.LogError(
-                    "Unable to rebuild playout; collection {@CollectionKey} contains items with zero duration!",
+                    "BUG: Unable to rebuild playout; collection {@CollectionKey} contains items with zero duration!",
                     zeroDurationCollection.ValueUnsafe());
 
                 return playout;