public async Task <List <VideoData> > GetUncategorizedVideos(List <string> playlistTitles)
{
var playlists = (await Playlists
.Where(x => playlistTitles.Contains(x.Title))
.ToListAsync())
.Select(x => x.Id)
.ToList();
var videosOnlyInOnePlaylist = new HashSet <string>(
PlaylistItems
.AsEnumerable()
.GroupBy(x => x.VideoId)
.Where(x => x.Count() <= 1)
.Select(x => new { VideoId = x.Key, PlaylistId = x.First().PlaylistDataId })
.Where(x => playlists.Any(y => x.PlaylistId == y))
.Select(x => x.VideoId)
);
return(await Videos.Where(x => videosOnlyInOnePlaylist.Contains(x.Id))
.OrderBy(x => x.Title)
.ToListAsync());
}
