fix: attach VFS children to first available media folder

- Attach VFS children to the first available media folder, instead of the first media folder in the list. If no media folders are available at all, then the VFS generation will be skipped (and Jellyfin will also internally skip the iteration of the children of the media folder if that were the case, so the shows/movies won't just disappear).

Shokofin/Configuration/MediaFolderConfigurationService.cs

@@ -7,6 +7,7 @@
 using Jellyfin.Data.Enums;
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Library;
+using MediaBrowser.Controller.Providers;
 using MediaBrowser.Model.IO;
 using Microsoft.Extensions.Logging;
 using Shokofin.API;
@@ -42,6 +43,8 @@ public class MediaFolderConfigurationService
 
     private readonly IFileSystem FileSystem;
 
+    private readonly IDirectoryService DirectoryService;
+
     private readonly ShokoAPIClient ApiClient;
 
     private readonly NamingOptions NamingOptions;
@@ -60,13 +63,15 @@ public MediaFolderConfigurationService(
         ILogger<MediaFolderConfigurationService> logger,
         ILibraryManager libraryManager,
         IFileSystem fileSystem,
+        IDirectoryService directoryService,
         ShokoAPIClient apiClient,
         NamingOptions namingOptions
     )
     {
         Logger = logger;
         LibraryManager = libraryManager;
         FileSystem = fileSystem;
+        DirectoryService = directoryService;
         ApiClient = apiClient;
         NamingOptions = namingOptions;
 
@@ -161,7 +166,7 @@ private void OnLibraryManagerItemRemoved(object? sender, ItemChangeEventArgs e)
                 return (string.Empty, string.Empty, null, new List<MediaFolderConfiguration>());
             return (
                 libraryFolder.GetVirtualRoot(),
-                virtualFolder.Locations[0],
+                virtualFolder.Locations.FirstOrDefault(a => DirectoryService.IsAccessible(a)) ?? string.Empty,
                 LibraryManager.GetConfiguredContentType(libraryFolder),
                 Plugin.Instance.Configuration.MediaFolders
                     .Where(config => config.IsMapped && config.LibraryId == mediaFolderConfig.LibraryId && (filter is null || filter(config)) && LibraryManager.GetItemById(config.MediaFolderId) is Folder)