Backport pull request #18090 from jellyfin/release-12.z

Reconcile missing episodes by episode, not by number

Original-merge: 1992491e17

Merged-by: crobibero <cody@robibe.ro>

Backported-by: Cody Robibero <cody@robibe.ro>

tests/Jellyfin.Providers.Tests/TV/SeriesMetadataServiceTests.cs

@@ -0,0 +1,107 @@
+using System.Collections.Generic;
+using MediaBrowser.Controller.Entities;
+using MediaBrowser.Controller.Entities.TV;
+using MediaBrowser.Model.Entities;
+using MediaBrowser.Model.IO;
+using MediaBrowser.Providers.TV;
+using Moq;
+using Xunit;
+
+namespace Jellyfin.Providers.Tests.TV;
+
+/// <summary>
+/// Covers reconciling missing episodes against the episodes the user has, which cannot be done on episode
+/// numbers alone: aired, DVD and absolute orders number the same episodes differently, so the tail of the
+/// longer order is the episodes the user owns rather than the ones they lack.
+/// </summary>
+public class SeriesMetadataServiceTests
+{
+    public SeriesMetadataServiceTests()
+    {
+        // An episode with a path asks the file system what kind of location it is. Only set when nothing else
+        // in the assembly has, since it is process-wide.
+        BaseItem.FileSystem ??= Mock.Of<IFileSystem>();
+    }
+
+    [Fact]
+    public void IsAlreadyPresent_VirtualEpisodeCarriesTheIdOfAPresentOne_ReturnsTrue()
+    {
+        // The Six Million Dollar Man S3: 21 files numbered in DVD order, 23 episodes in aired order, so
+        // aired 22 and 23 are the files stored as 20 and 21.
+        var present = SeriesMetadataService.GetPresentEpisodeIds(
+        [
+            Physical(20, (MetadataProvider.Tvdb, "236715")),
+            Physical(21, (MetadataProvider.Tvdb, "236716"))
+        ]);
+
+        Assert.True(SeriesMetadataService.IsAlreadyPresent(Virtual(22, (MetadataProvider.Tvdb, "236715")), present));
+        Assert.True(SeriesMetadataService.IsAlreadyPresent(Virtual(23, (MetadataProvider.Tvdb, "236716")), present));
+    }
+
+    [Fact]
+    public void IsAlreadyPresent_GenuinelyMissingEpisode_ReturnsFalse()
+    {
+        // The aired-only two-parter the user really does not have keeps its missing episodes.
+        var present = SeriesMetadataService.GetPresentEpisodeIds(
+        [
+            Physical(20, (MetadataProvider.Tvdb, "236715")),
+            Physical(21, (MetadataProvider.Tvdb, "236716"))
+        ]);
+
+        Assert.False(SeriesMetadataService.IsAlreadyPresent(Virtual(15, (MetadataProvider.Tvdb, "4273533")), present));
+    }
+
+    [Fact]
+    public void GetPresentEpisodeIds_IdSharedBySeveralEpisodes_IsNotAnIdentity()
+    {
+        // A series' own IMDb id lands on every episode, and TMDb reports an unknown TVRage id as 0. Taking
+        // either for an episode identity would let one file delete every missing episode of the series.
+        var present = SeriesMetadataService.GetPresentEpisodeIds(
+        [
+            Physical(1, (MetadataProvider.Imdb, "tt0836592"), (MetadataProvider.TvRage, "0"), (MetadataProvider.Tvdb, "1001")),
+            Physical(2, (MetadataProvider.Imdb, "tt0836592"), (MetadataProvider.TvRage, "0"), (MetadataProvider.Tvdb, "1002"))
+        ]);
+
+        Assert.False(SeriesMetadataService.IsAlreadyPresent(Virtual(3, (MetadataProvider.Imdb, "tt0836592")), present));
+        Assert.False(SeriesMetadataService.IsAlreadyPresent(Virtual(4, (MetadataProvider.TvRage, "0")), present));
+        Assert.True(SeriesMetadataService.IsAlreadyPresent(Virtual(5, (MetadataProvider.Tvdb, "1001")), present));
+    }
+
+    [Fact]
+    public void GetPresentEpisodeIds_VirtualEpisode_DoesNotCountAsPresent()
+    {
+        // Two virtual episodes for the same episode must not cancel each other out into "present".
+        var present = SeriesMetadataService.GetPresentEpisodeIds(
+        [
+            Virtual(22, (MetadataProvider.Tvdb, "236715"))
+        ]);
+
+        Assert.Empty(present);
+    }
+
+    [Fact]
+    public void GetPresentEpisodeIds_BlankStoredId_IsIgnored()
+    {
+        // SetProviderId refuses these, but a row written by an older version can still hold one.
+        var episode = Physical(1);
+        episode.ProviderIds["Tvdb"] = " ";
+
+        Assert.Empty(SeriesMetadataService.GetPresentEpisodeIds([episode]));
+    }
+
+    private static Episode Physical(int indexNumber, params (MetadataProvider Provider, string Id)[] providerIds)
+        => WithIds(new Episode { IndexNumber = indexNumber, Path = $"/media/show/Season 03/E{indexNumber}.mkv" }, providerIds);
+
+    private static Episode Virtual(int indexNumber, params (MetadataProvider Provider, string Id)[] providerIds)
+        => WithIds(new Episode { IndexNumber = indexNumber, IsVirtualItem = true }, providerIds);
+
+    private static Episode WithIds(Episode episode, IEnumerable<(MetadataProvider Provider, string Id)> providerIds)
+    {
+        foreach (var (provider, id) in providerIds)
+        {
+            episode.SetProviderId(provider, id);
+        }
+
+        return episode;
+    }
+}