support multi-episode files from plex (#243)

* minor fallback metadata bug fixes

* support multi-episode files from plex

ErsatzTV.Infrastructure/Plex/PlexServerApiClient.cs

@@ -110,7 +110,8 @@ namespace ErsatzTV.Infrastructure.Plex
                 IPlexServerApi service = XmlServiceFor(connection.Uri);
                 return await service.GetSeasonChildren(season.Key.Split("/").Reverse().Skip(1).Head(), token.AuthToken)
                     .Map(r => r.Metadata.Filter(m => m.Media.Count > 0 && m.Media[0].Part.Count > 0))
-                    .Map(list => list.Map(metadata => ProjectToEpisode(metadata, library.MediaSourceId)).ToList());
+                    .Map(list => list.Map(metadata => ProjectToEpisode(metadata, library.MediaSourceId)))
+                    .Map(ProcessMultiEpisodeFiles);
             }
             catch (Exception ex)
             {
@@ -118,6 +119,27 @@ namespace ErsatzTV.Infrastructure.Plex
             }
         }
 
+        private List<PlexEpisode> ProcessMultiEpisodeFiles(IEnumerable<PlexEpisode> episodes)
+        {
+            // add all metadata from duplicate paths to first entry with given path
+            // i.e. s1e1 episode will add s1e2 metadata if s1e1 and s1e2 have same physical path
+            var result = new Dictionary<string, PlexEpisode>();
+            foreach (PlexEpisode episode in episodes.OrderBy(e => e.EpisodeMetadata.Head().EpisodeNumber))
+            {
+                string path = episode.MediaVersions.Head().MediaFiles.Head().Path;
+                if (result.TryGetValue(path, out PlexEpisode existing))
+                {
+                    existing.EpisodeMetadata.Add(episode.EpisodeMetadata.Head());
+                }
+                else
+                {
+                    result.Add(path, episode);
+                }
+            }
+
+            return result.Values.ToList();
+        }
+
         public async Task<Either<BaseError, MovieMetadata>> GetMovieMetadata(
             PlexLibrary library,
             string key,