media source scan interval (#28)

* scan media sources once every six hours

* cleanup

* force scan from ui

ErsatzTV.Core/Domain/MediaSource.cs

@@ -1,9 +1,12 @@
-namespace ErsatzTV.Core.Domain
+using System;
+
+namespace ErsatzTV.Core.Domain
 {
     public abstract class MediaSource
     {
         public int Id { get; set; }
         public MediaSourceType SourceType { get; set; }
         public string Name { get; set; }
+        public DateTimeOffset? LastScan { get; set; }
     }
 }

ErsatzTV.Core/Errors/MediaSourceRecentlyScanned.cs

@@ -0,0 +1,10 @@
+namespace ErsatzTV.Core.Errors
+{
+    public class MediaSourceRecentlyScanned : BaseError
+    {
+        public MediaSourceRecentlyScanned(string folder) :
+            base($"Media source {folder} was already scanned recently; skipping scan.")
+        {
+        }
+    }
+}

ErsatzTV.Core/Interfaces/Repositories/IMediaSourceRepository.cs

@@ -14,6 +14,7 @@ namespace ErsatzTV.Core.Interfaces.Repositories
         Task<Option<MediaSource>> Get(int id);
         Task<Option<PlexMediaSource>> GetPlex(int id);
         Task<int> CountMediaItems(int id);
+        Task Update(LocalMediaSource localMediaSource);
         Task Update(PlexMediaSource plexMediaSource);
         Task Delete(int id);
     }

ErsatzTV.Core/Metadata/LocalMetadataProvider.cs

@@ -197,7 +197,9 @@ namespace ErsatzTV.Core.Metadata
             }
         }
 
-        private async Task<Option<TelevisionEpisodeMetadata>> LoadEpisodeMetadata(TelevisionEpisodeMediaItem mediaItem, string nfoFileName)
+        private async Task<Option<TelevisionEpisodeMetadata>> LoadEpisodeMetadata(
+            TelevisionEpisodeMediaItem mediaItem,
+            string nfoFileName)
         {
             try
             {