diff --git a/Kyoo.Common/Controllers/ILibraryManager.cs b/Kyoo.Common/Controllers/ILibraryManager.cs
index 133fa7c5..75e2b53f 100644
--- a/Kyoo.Common/Controllers/ILibraryManager.cs
+++ b/Kyoo.Common/Controllers/ILibraryManager.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using JetBrains.Annotations;
 using Kyoo.Models;
 
 namespace Kyoo.Controllers
@@ -20,35 +21,40 @@ namespace Kyoo.Controllers
 		Task<People> GetPeople(string slug);
 
 		// Get by relations
-		Task<IEnumerable<Season>> GetSeasons(long showID);
-		Task<IEnumerable<Season>> GetSeasons(string showSlug);
+		Task<ICollection<Season>> GetSeasons(long showID);
+		Task<ICollection<Season>> GetSeasons(string showSlug);
 		
-		Task<IEnumerable<Episode>> GetEpisodes(long showID, long seasonNumber);
-		Task<IEnumerable<Episode>> GetEpisodes(string showSlug, long seasonNumber);
-		Task<IEnumerable<Episode>> GetEpisodes(long seasonID);
+		Task<ICollection<Episode>> GetEpisodes(long showID, long seasonNumber);
+		Task<ICollection<Episode>> GetEpisodes(string showSlug, long seasonNumber);
+		Task<ICollection<Episode>> GetEpisodes(long seasonID);
 		
 		
+		// Helpers
+		Task<Show> GetShowByPath(string path);
+		Task AddShowLink(long showID, long? libraryID, long? collectionID);
+		Task AddShowLink([NotNull] Show show, Library library, Collection collection);
+		
 		// Get all
-		Task<IEnumerable<Library>> GetLibraries();
-		Task<IEnumerable<Collection>> GetCollections();
-		Task<IEnumerable<Show>> GetShows();
-		Task<IEnumerable<Season>> GetSeasons();
-		Task<IEnumerable<Episode>> GetEpisodes();
-		Task<IEnumerable<Track>> GetTracks();
-		Task<IEnumerable<Studio>> GetStudios();
-		Task<IEnumerable<People>> GetPeoples();
-		Task<IEnumerable<Genre>> GetGenres();
-		Task<IEnumerable<ProviderID>> GetProviders();
+		Task<ICollection<Library>> GetLibraries();
+		Task<ICollection<Collection>> GetCollections();
+		Task<ICollection<Show>> GetShows();
+		Task<ICollection<Season>> GetSeasons();
+		Task<ICollection<Episode>> GetEpisodes();
+		Task<ICollection<Track>> GetTracks();
+		Task<ICollection<Studio>> GetStudios();
+		Task<ICollection<People>> GetPeoples();
+		Task<ICollection<Genre>> GetGenres();
+		Task<ICollection<ProviderID>> GetProviders();
 
 		// Search
-		Task<IEnumerable<Library>> SearchLibraries(string searchQuery);
-		Task<IEnumerable<Collection>> SearchCollections(string searchQuery);
-		Task<IEnumerable<Show>> SearchShows(string searchQuery);
-		Task<IEnumerable<Season>> SearchSeasons(string searchQuery);
-		Task<IEnumerable<Episode>> SearchEpisodes(string searchQuery);
-		Task<IEnumerable<Genre>> SearchGenres(string searchQuery);
-		Task<IEnumerable<Studio>> SearchStudios(string searchQuery);
-		Task<IEnumerable<People>> SearchPeople(string searchQuery);
+		Task<ICollection<Library>> SearchLibraries(string searchQuery);
+		Task<ICollection<Collection>> SearchCollections(string searchQuery);
+		Task<ICollection<Show>> SearchShows(string searchQuery);
+		Task<ICollection<Season>> SearchSeasons(string searchQuery);
+		Task<ICollection<Episode>> SearchEpisodes(string searchQuery);
+		Task<ICollection<Genre>> SearchGenres(string searchQuery);
+		Task<ICollection<Studio>> SearchStudios(string searchQuery);
+		Task<ICollection<People>> SearchPeople(string searchQuery);
 		
 		//Register values
 		Task RegisterLibrary(Library library);
diff --git a/Kyoo.Common/Controllers/IRepository.cs b/Kyoo.Common/Controllers/IRepository.cs
index af30eb88..a63886ea 100644
--- a/Kyoo.Common/Controllers/IRepository.cs
+++ b/Kyoo.Common/Controllers/IRepository.cs
@@ -9,31 +9,35 @@ namespace Kyoo.Controllers
 	{
 		Task<T> Get(long id);
 		Task<T> Get(string slug);
-		Task<IEnumerable<T>> Search(string query);
-		Task<IEnumerable<T>> GetAll();
+		Task<ICollection<T>> Search(string query);
+		Task<ICollection<T>> GetAll();
 		Task<long> Create([NotNull] T obj);
 		Task<long> CreateIfNotExists([NotNull] T obj);
 		Task Edit([NotNull] T edited, bool resetOld);
 		Task Delete(T obj);
 	}
-	
-	public interface IShowRepository : IRepository<Show> {}
+
+	public interface IShowRepository : IRepository<Show>
+	{
+		Task<Show> GetByPath(string path);
+		Task AddShowLink(long showID, long? libraryID, long? collectionID);
+	}
 
 	public interface ISeasonRepository : IRepository<Season>
 	{
 		Task<Season> Get(string showSlug, long seasonNumber);
 		
-		Task<IEnumerable<Season>> GetSeasons(long showID);
-		Task<IEnumerable<Season>> GetSeasons(string showSlug);
+		Task<ICollection<Season>> GetSeasons(long showID);
+		Task<ICollection<Season>> GetSeasons(string showSlug);
 	}
 	
 	public interface IEpisodeRepository : IRepository<Episode>
 	{
 		Task<Episode> Get(string showSlug, long seasonNumber, long episodeNumber);
 		
-		Task<IEnumerable<Episode>> GetEpisodes(long showID, long seasonNumber);
-		Task<IEnumerable<Episode>> GetEpisodes(string showSlug, long seasonNumber);
-		Task<IEnumerable<Episode>> GetEpisodes(long seasonID);
+		Task<ICollection<Episode>> GetEpisodes(long showID, long seasonNumber);
+		Task<ICollection<Episode>> GetEpisodes(string showSlug, long seasonNumber);
+		Task<ICollection<Episode>> GetEpisodes(long seasonID);
 	}
 
 	public interface ITrackRepository : IRepository<Track>
diff --git a/Kyoo.Common/Models/Task.cs b/Kyoo.Common/Models/Task.cs
index f00b24c2..76cfbc52 100644
--- a/Kyoo.Common/Models/Task.cs
+++ b/Kyoo.Common/Models/Task.cs
@@ -14,7 +14,7 @@ namespace Kyoo.Models
 		public bool RunOnStartup { get; }
 		public int Priority { get; }
 		public Task Run(IServiceProvider serviceProvider, CancellationToken cancellationToken, string arguments = null);
-		public IEnumerable<string> GetPossibleParameters();
+		public Task<IEnumerable<string>> GetPossibleParameters();
 		public int? Progress();
 	}
 }
\ No newline at end of file
diff --git a/Kyoo/Controllers/LibraryManager.cs b/Kyoo/Controllers/LibraryManager.cs
index 60ca9f79..82f8f5ea 100644
--- a/Kyoo/Controllers/LibraryManager.cs
+++ b/Kyoo/Controllers/LibraryManager.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Threading.Tasks;
 using Kyoo.Models;
 
@@ -86,117 +87,134 @@ namespace Kyoo.Controllers
 			return _people.Get(slug);
 		}
 
-		public Task<IEnumerable<Library>> GetLibraries()
+		public Task<ICollection<Library>> GetLibraries()
 		{
 			return _libraries.GetAll();
 		}
 
-		public Task<IEnumerable<Collection>> GetCollections()
+		public Task<ICollection<Collection>> GetCollections()
 		{
 			return _collections.GetAll();
 		}
 
-		public Task<IEnumerable<Show>> GetShows()
+		public Task<ICollection<Show>> GetShows()
 		{
 			return _shows.GetAll();
 		}
 
-		public Task<IEnumerable<Season>> GetSeasons()
+		public Task<ICollection<Season>> GetSeasons()
 		{
 			return _seasons.GetAll();
 		}
 
-		public Task<IEnumerable<Episode>> GetEpisodes()
+		public Task<ICollection<Episode>> GetEpisodes()
 		{
 			return _episodes.GetAll();
 		}
 
-		public Task<IEnumerable<Track>> GetTracks()
+		public Task<ICollection<Track>> GetTracks()
 		{
 			return _tracks.GetAll();
 		}
 
-		public Task<IEnumerable<Studio>> GetStudios()
+		public Task<ICollection<Studio>> GetStudios()
 		{
 			return _studios.GetAll();
 		}
 
-		public Task<IEnumerable<People>> GetPeoples()
+		public Task<ICollection<People>> GetPeoples()
 		{
 			return _people.GetAll();
 		}
 
-		public Task<IEnumerable<Genre>> GetGenres()
+		public Task<ICollection<Genre>> GetGenres()
 		{
 			return _genres.GetAll();
 		}
 
-		public Task<IEnumerable<ProviderID>> GetProviders()
+		public Task<ICollection<ProviderID>> GetProviders()
 		{
 			return _providers.GetAll();
 		}
 
-		public Task<IEnumerable<Season>> GetSeasons(long showID)
+		public Task<ICollection<Season>> GetSeasons(long showID)
 		{
 			return _seasons.GetSeasons(showID);
 		}
 
-		public Task<IEnumerable<Season>> GetSeasons(string showSlug)
+		public Task<ICollection<Season>> GetSeasons(string showSlug)
 		{
 			return _seasons.GetSeasons(showSlug);
 		}
 
-		public Task<IEnumerable<Episode>> GetEpisodes(long showID, long seasonNumber)
+		public Task<ICollection<Episode>> GetEpisodes(long showID, long seasonNumber)
 		{
 			return _episodes.GetEpisodes(showID, seasonNumber);
 		}
 
-		public Task<IEnumerable<Episode>> GetEpisodes(string showSlug, long seasonNumber)
+		public Task<ICollection<Episode>> GetEpisodes(string showSlug, long seasonNumber)
 		{
 			return _episodes.GetEpisodes(showSlug, seasonNumber);
 		}
 
-		public Task<IEnumerable<Episode>> GetEpisodes(long seasonID)
+		public Task<ICollection<Episode>> GetEpisodes(long seasonID)
 		{
 			return _episodes.GetEpisodes(seasonID);
 		}
 
-		public Task<IEnumerable<Library>> SearchLibraries(string searchQuery)
+		public Task<Show> GetShowByPath(string path)
+		{
+			return _shows.GetByPath(path);
+		}
+
+		public Task AddShowLink(long showID, long? libraryID, long? collectionID)
+		{
+			return _shows.AddShowLink(showID, libraryID, collectionID);
+		}
+
+		public Task AddShowLink(Show show, Library library, Collection collection)
+		{
+			if (show == null)
+				throw new ArgumentNullException(nameof(show));
+			return AddShowLink(show.ID, library?.ID, collection?.ID);
+		}
+		
+		public Task<ICollection<Library>> SearchLibraries(string searchQuery)
 		{
 			return _libraries.Search(searchQuery);
 		}
 
-		public Task<IEnumerable<Collection>> SearchCollections(string searchQuery)
+		public Task<ICollection<Collection>> SearchCollections(string searchQuery)
 		{
 			return _collections.Search(searchQuery);
 		}
 
-		public Task<IEnumerable<Show>> SearchShows(string searchQuery)
+		public Task<ICollection<Show>> SearchShows(string searchQuery)
 		{
 			return _shows.Search(searchQuery);
 		}
 
-		public Task<IEnumerable<Season>> SearchSeasons(string searchQuery)
+		public Task<ICollection<Season>> SearchSeasons(string searchQuery)
 		{
 			return _seasons.Search(searchQuery);
 		}
 
-		public Task<IEnumerable<Episode>> SearchEpisodes(string searchQuery)
+		public Task<ICollection<Episode>> SearchEpisodes(string searchQuery)
 		{
 			return _episodes.Search(searchQuery);
 		}
 
-		public Task<IEnumerable<Genre>> SearchGenres(string searchQuery)
+		public Task<ICollection<Genre>> SearchGenres(string searchQuery)
 		{
 			return _genres.Search(searchQuery);
 		}
 
-		public Task<IEnumerable<Studio>> SearchStudios(string searchQuery)
+		public Task<ICollection<Studio>> SearchStudios(string searchQuery)
 		{
 			return _studios.Search(searchQuery);
 		}
 
-		public Task<IEnumerable<People>> SearchPeople(string searchQuery)
+		public Task<ICollection<People>> SearchPeople(string searchQuery)
 		{
 			return _people.Search(searchQuery);
 		}
diff --git a/Kyoo/Controllers/Repositories/CollectionRepository.cs b/Kyoo/Controllers/Repositories/CollectionRepository.cs
index c0b38434..476ffd67 100644
--- a/Kyoo/Controllers/Repositories/CollectionRepository.cs
+++ b/Kyoo/Controllers/Repositories/CollectionRepository.cs
@@ -28,7 +28,7 @@ namespace Kyoo.Controllers
 			return _database.Collections.FirstOrDefaultAsync(x => x.Slug == slug);
 		}
 		
-		public async Task<IEnumerable<Collection>> Search(string query)
+		public async Task<ICollection<Collection>> Search(string query)
 		{
 			return await _database.Collections
 				.Where(x => EF.Functions.Like(x.Name, $"%{query}%"))
@@ -36,7 +36,7 @@ namespace Kyoo.Controllers
 				.ToListAsync();
 		}
 
-		public async Task<IEnumerable<Collection>> GetAll()
+		public async Task<ICollection<Collection>> GetAll()
 		{
 			return await _database.Collections.ToListAsync();
 		}
diff --git a/Kyoo/Controllers/Repositories/EpisodeRepository.cs b/Kyoo/Controllers/Repositories/EpisodeRepository.cs
index 71fcfebd..dd92ad85 100644
--- a/Kyoo/Controllers/Repositories/EpisodeRepository.cs
+++ b/Kyoo/Controllers/Repositories/EpisodeRepository.cs
@@ -46,7 +46,7 @@ namespace Kyoo.Controllers
 			                                                         && x.EpisodeNumber == episodeNumber);
 		}
 		
-		public async Task<IEnumerable<Episode>> Search(string query)
+		public async Task<ICollection<Episode>> Search(string query)
 		{
 			return await _database.Episodes
 				.Where(x => EF.Functions.Like(x.Title, $"%{query}%"))
@@ -54,7 +54,7 @@ namespace Kyoo.Controllers
 				.ToListAsync();
 		}
 
-		public async Task<IEnumerable<Episode>> GetAll()
+		public async Task<ICollection<Episode>> GetAll()
 		{
 			return await _database.Episodes.ToListAsync();
 		}
@@ -64,10 +64,7 @@ namespace Kyoo.Controllers
 			if (obj == null)
 				throw new ArgumentNullException(nameof(obj));
 			
-			obj.Show = null;
-			obj.Season = null;
 			await Validate(obj);
-
 			await _database.Episodes.AddAsync(obj);
 			await _database.SaveChangesAsync();
 			return obj.ID;
@@ -120,19 +117,19 @@ namespace Kyoo.Controllers
 			await _database.SaveChangesAsync();
 		}
 		
-		public async Task<IEnumerable<Episode>> GetEpisodes(long showID, long seasonNumber)
+		public async Task<ICollection<Episode>> GetEpisodes(long showID, long seasonNumber)
 		{
 			return await _database.Episodes.Where(x => x.ShowID == showID
 			                                     && x.SeasonNumber == seasonNumber).ToListAsync();
 		}
 
-		public async Task<IEnumerable<Episode>> GetEpisodes(string showSlug, long seasonNumber)
+		public async Task<ICollection<Episode>> GetEpisodes(string showSlug, long seasonNumber)
 		{
 			return await _database.Episodes.Where(x => x.Show.Slug == showSlug
 			                                           && x.SeasonNumber == seasonNumber).ToListAsync();
 		}
 
-		public async Task<IEnumerable<Episode>> GetEpisodes(long seasonID)
+		public async Task<ICollection<Episode>> GetEpisodes(long seasonID)
 		{
 			return await _database.Episodes.Where(x => x.SeasonID == seasonID).ToListAsync();
 		}
diff --git a/Kyoo/Controllers/Repositories/GenreRepository.cs b/Kyoo/Controllers/Repositories/GenreRepository.cs
index 5544c07b..1035e54b 100644
--- a/Kyoo/Controllers/Repositories/GenreRepository.cs
+++ b/Kyoo/Controllers/Repositories/GenreRepository.cs
@@ -28,7 +28,7 @@ namespace Kyoo.Controllers
 			return await _database.Genres.FirstOrDefaultAsync(x => x.Slug == slug);
 		}
 
-		public async Task<IEnumerable<Genre>> Search(string query)
+		public async Task<ICollection<Genre>> Search(string query)
 		{
 			return await _database.Genres
 				.Where(genre => EF.Functions.Like(genre.Name, $"%{query}%"))
@@ -36,7 +36,7 @@ namespace Kyoo.Controllers
 				.ToListAsync();
 		}
 
-		public async Task<IEnumerable<Genre>> GetAll()
+		public async Task<ICollection<Genre>> GetAll()
 		{
 			return await _database.Genres.ToListAsync();
 		}
diff --git a/Kyoo/Controllers/Repositories/LibraryRepository.cs b/Kyoo/Controllers/Repositories/LibraryRepository.cs
index bac6e6ba..c73af246 100644
--- a/Kyoo/Controllers/Repositories/LibraryRepository.cs
+++ b/Kyoo/Controllers/Repositories/LibraryRepository.cs
@@ -30,7 +30,7 @@ namespace Kyoo.Controllers
 			return _database.Libraries.FirstOrDefaultAsync(x => x.Name == slug);
 		}
 
-		public async Task<IEnumerable<Library>> Search(string query)
+		public async Task<ICollection<Library>> Search(string query)
 		{
 			return await _database.Libraries
 				.Where(x => EF.Functions.Like(x.Name, $"%{query}%"))
@@ -38,7 +38,7 @@ namespace Kyoo.Controllers
 				.ToListAsync();
 		}
 
-		public async Task<IEnumerable<Library>> GetAll()
+		public async Task<ICollection<Library>> GetAll()
 		{
 			return await _database.Libraries.ToListAsync();
 		}
diff --git a/Kyoo/Controllers/Repositories/PeopleRepository.cs b/Kyoo/Controllers/Repositories/PeopleRepository.cs
index f6a85c1a..0b702be5 100644
--- a/Kyoo/Controllers/Repositories/PeopleRepository.cs
+++ b/Kyoo/Controllers/Repositories/PeopleRepository.cs
@@ -29,7 +29,7 @@ namespace Kyoo.Controllers
 			return _database.Peoples.FirstOrDefaultAsync(x => x.Slug == slug);
 		}
 
-		public async Task<IEnumerable<People>> Search(string query)
+		public async Task<ICollection<People>> Search(string query)
 		{
 			return await _database.Peoples
 				.Where(people => EF.Functions.Like(people.Name, $"%{query}%"))
@@ -37,7 +37,7 @@ namespace Kyoo.Controllers
 				.ToListAsync();
 		}
 
-		public async Task<IEnumerable<People>> GetAll()
+		public async Task<ICollection<People>> GetAll()
 		{
 			return await _database.Peoples.ToListAsync();
 		}
diff --git a/Kyoo/Controllers/Repositories/ProviderRepository.cs b/Kyoo/Controllers/Repositories/ProviderRepository.cs
index 01e2898a..4f9b85aa 100644
--- a/Kyoo/Controllers/Repositories/ProviderRepository.cs
+++ b/Kyoo/Controllers/Repositories/ProviderRepository.cs
@@ -28,7 +28,7 @@ namespace Kyoo.Controllers
 			return await _database.Providers.FirstOrDefaultAsync(x => x.Name == slug);
 		}
 
-		public async Task<IEnumerable<ProviderID>> Search(string query)
+		public async Task<ICollection<ProviderID>> Search(string query)
 		{
 			return await _database.Providers
 				.Where(x => EF.Functions.Like(x.Name, $"%{query}%"))
@@ -36,7 +36,7 @@ namespace Kyoo.Controllers
 				.ToListAsync();
 		}
 
-		public async Task<IEnumerable<ProviderID>> GetAll()
+		public async Task<ICollection<ProviderID>> GetAll()
 		{
 			return await _database.Providers.ToListAsync();
 		}
diff --git a/Kyoo/Controllers/Repositories/SeasonRepository.cs b/Kyoo/Controllers/Repositories/SeasonRepository.cs
index 98d1fe26..686308dc 100644
--- a/Kyoo/Controllers/Repositories/SeasonRepository.cs
+++ b/Kyoo/Controllers/Repositories/SeasonRepository.cs
@@ -42,7 +42,7 @@ namespace Kyoo.Controllers
 			                                                        && x.SeasonNumber == seasonNumber);
 		}
 
-		public async Task<IEnumerable<Season>> Search(string query)
+		public async Task<ICollection<Season>> Search(string query)
 		{
 			return await _database.Seasons
 				.Where(x => EF.Functions.Like(x.Title, $"%{query}%"))
@@ -50,7 +50,7 @@ namespace Kyoo.Controllers
 				.ToListAsync();
 		}
 
-		public async Task<IEnumerable<Season>> GetAll()
+		public async Task<ICollection<Season>> GetAll()
 		{
 			return await _database.Seasons.ToListAsync();
 		}
@@ -116,12 +116,12 @@ namespace Kyoo.Controllers
 			await _database.SaveChangesAsync();
 		}
 		
-		public async Task<IEnumerable<Season>> GetSeasons(long showID)
+		public async Task<ICollection<Season>> GetSeasons(long showID)
 		{
 			return await _database.Seasons.Where(x => x.ShowID == showID).ToListAsync();
 		}
 
-		public async Task<IEnumerable<Season>> GetSeasons(string showSlug)
+		public async Task<ICollection<Season>> GetSeasons(string showSlug)
 		{
 			return await _database.Seasons.Where(x => x.Show.Slug == showSlug).ToListAsync();
 		}
diff --git a/Kyoo/Controllers/Repositories/ShowRepository.cs b/Kyoo/Controllers/Repositories/ShowRepository.cs
index e0901cfc..21ce741b 100644
--- a/Kyoo/Controllers/Repositories/ShowRepository.cs
+++ b/Kyoo/Controllers/Repositories/ShowRepository.cs
@@ -39,7 +39,12 @@ namespace Kyoo.Controllers
 			return await _database.Shows.FirstOrDefaultAsync(x => x.Slug == slug);
 		}
 
-		public async Task<IEnumerable<Show>> Search(string query)
+		public async Task<Show> GetByPath(string path)
+		{
+			return await _database.Shows.FirstOrDefaultAsync(x => x.Path == path);
+		}
+
+		public async Task<ICollection<Show>> Search(string query)
 		{
 			return await _database.Shows
 				.FromSqlInterpolated($@"SELECT * FROM Shows WHERE Shows.Title LIKE {$"%{query}%"}
@@ -48,7 +53,7 @@ namespace Kyoo.Controllers
 				.ToListAsync();
 		}
 
-		public async Task<IEnumerable<Show>> GetAll()
+		public async Task<ICollection<Show>> GetAll()
 		{
 			return await _database.Shows.ToListAsync();
 		}
@@ -121,5 +126,28 @@ namespace Kyoo.Controllers
 			_database.Shows.Remove(show);
 			await _database.SaveChangesAsync();
 		}
+		
+		public Task AddShowLink(long showID, long? libraryID, long? collectionID)
+		{
+			if (collectionID != null)
+			{
+				_database.CollectionLinks.AddIfNotExist(new CollectionLink { CollectionID = collectionID, ShowID = showID},
+					x => x.CollectionID == collectionID && x.ShowID == showID);
+			}
+			if (libraryID != null)
+			{
+				_database.LibraryLinks.AddIfNotExist(new LibraryLink {LibraryID = libraryID.Value, ShowID = showID},
+					x => x.LibraryID == libraryID.Value && x.CollectionID == null && x.ShowID == showID);
+			}
+
+			if (libraryID != null && collectionID != null)
+			{
+				_database.LibraryLinks.AddIfNotExist(
+					new LibraryLink {LibraryID = libraryID.Value, CollectionID = collectionID.Value},
+					x => x.LibraryID == libraryID && x.CollectionID == collectionID && x.ShowID == null);
+			}
+
+			return Task.CompletedTask;
+		}
 	}
 }
\ No newline at end of file
diff --git a/Kyoo/Controllers/Repositories/StudioRepository.cs b/Kyoo/Controllers/Repositories/StudioRepository.cs
index c7d77f18..f531d7c1 100644
--- a/Kyoo/Controllers/Repositories/StudioRepository.cs
+++ b/Kyoo/Controllers/Repositories/StudioRepository.cs
@@ -28,7 +28,7 @@ namespace Kyoo.Controllers
 			return await _database.Studios.FirstOrDefaultAsync(x => x.Name == slug);
 		}
 
-		public async Task<IEnumerable<Studio>> Search(string query)
+		public async Task<ICollection<Studio>> Search(string query)
 		{
 			return await _database.Studios
 				.Where(x => EF.Functions.Like(x.Name, $"%{query}%"))
@@ -36,7 +36,7 @@ namespace Kyoo.Controllers
 				.ToListAsync();
 		}
 
-		public async Task<IEnumerable<Studio>> GetAll()
+		public async Task<ICollection<Studio>> GetAll()
 		{
 			return await _database.Studios.ToListAsync();
 		}
diff --git a/Kyoo/Controllers/Repositories/TrackRepository.cs b/Kyoo/Controllers/Repositories/TrackRepository.cs
index a5d58aa0..be67ab2c 100644
--- a/Kyoo/Controllers/Repositories/TrackRepository.cs
+++ b/Kyoo/Controllers/Repositories/TrackRepository.cs
@@ -34,12 +34,12 @@ namespace Kyoo.Controllers
 			                                                       && x.IsForced == isForced);
 		}
 
-		public Task<IEnumerable<Track>> Search(string query)
+		public Task<ICollection<Track>> Search(string query)
 		{
 			throw new InvalidOperationException("Tracks do not support the search method.");
 		}
 
-		public async Task<IEnumerable<Track>> GetAll()
+		public async Task<ICollection<Track>> GetAll()
 		{
 			return await _database.Tracks.ToListAsync();
 		}
diff --git a/Kyoo/Tasks/Crawler.cs b/Kyoo/Tasks/Crawler.cs
index 065bc613..70a88b6c 100644
--- a/Kyoo/Tasks/Crawler.cs
+++ b/Kyoo/Tasks/Crawler.cs
@@ -8,7 +8,6 @@ using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
 using Kyoo.Models.Watch;
-using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace Kyoo.Controllers
@@ -28,11 +27,11 @@ namespace Kyoo.Controllers
 		private ITranscoder _transcoder;
 		private IConfiguration _config;
 		
-		public IEnumerable<string> GetPossibleParameters()
+		public async Task<IEnumerable<string>> GetPossibleParameters()
 		{
 			using IServiceScope serviceScope = _serviceProvider.CreateScope();
 			ILibraryManager libraryManager = serviceScope.ServiceProvider.GetService<ILibraryManager>();
-			return libraryManager.GetLibraries().Select(x => x.Slug);
+			return (await libraryManager.GetLibraries()).Select(x => x.Slug);
 		}
 
 		public int? Progress()
@@ -53,28 +52,27 @@ namespace Kyoo.Controllers
 			{
 				using IServiceScope serviceScope = _serviceProvider.CreateScope();
 				ILibraryManager libraryManager = serviceScope.ServiceProvider.GetService<ILibraryManager>();
-				IEnumerable<Episode> episodes = libraryManager.GetEpisodes();
-				IEnumerable<Library> libraries = argument == null 
-					? libraryManager.GetLibraries()
-					: new [] {libraryManager.GetLibrary(argument)};
+				ICollection<Episode> episodes = await libraryManager.GetEpisodes();
+				ICollection<Library> libraries = argument == null 
+					? await libraryManager.GetLibraries()
+					: new [] { await libraryManager.GetLibrary(argument)};
 
 				foreach (Episode episode in episodes)
 				{
 					if (!File.Exists(episode.Path))
-						libraryManager.RemoveEpisode(episode);
+						await libraryManager.DeleteEpisode(episode);
 				}
-				await libraryManager.SaveChanges();
 
-				await Task.WhenAll(libraries.ToList().Select(x => Scan(x, libraryManager, cancellationToken)));
+				await Task.WhenAll(libraries.Select(x => Scan(x, episodes, cancellationToken)));
 			}
 			catch (Exception ex)
 			{
-				Console.Error.WriteLine($"Unknown exception thrown durring libraries scan.\nException: {ex.Message}");
+				await Console.Error.WriteLineAsync($"Unknown exception thrown durring libraries scan.\nException: {ex.Message}");
 			}
 			Console.WriteLine("Scan finished!");
 		}
 
-		private Task Scan(Library library, ILibraryManager libraryManager, CancellationToken cancellationToken)
+		private Task Scan(Library library, ICollection<Episode> episodes, CancellationToken cancellationToken)
 		{
 			Console.WriteLine($"Scanning library {library.Name} at {string.Join(", ", library.Paths)}.");
 			return Task.WhenAll(library.Paths.Select(async path =>
@@ -89,29 +87,29 @@ namespace Kyoo.Controllers
 				}
 				catch (DirectoryNotFoundException)
 				{
-					Console.Error.WriteLine($"The library's directory {path} could not be found (library slug: {library.Slug})");
+					await Console.Error.WriteLineAsync($"The library's directory {path} could not be found (library slug: {library.Slug})");
 					return Task.CompletedTask;
 				}
 				catch (PathTooLongException)
 				{
-					Console.Error.WriteLine($"The library's directory {path} is too long for this system. (library slug: {library.Slug})");
+					await Console.Error.WriteLineAsync($"The library's directory {path} is too long for this system. (library slug: {library.Slug})");
 					return Task.CompletedTask;
 				}
 				catch (ArgumentException)
 				{
-					Console.Error.WriteLine($"The library's directory {path} is invalid. (library slug: {library.Slug})");
+					await Console.Error.WriteLineAsync($"The library's directory {path} is invalid. (library slug: {library.Slug})");
 					return Task.CompletedTask;
 				}
 				catch (UnauthorizedAccessException)
 				{
-					Console.Error.WriteLine($"Permission denied: can't access library's directory at {path}. (library slug: {library.Slug})");
+					await Console.Error.WriteLineAsync($"Permission denied: can't access library's directory at {path}. (library slug: {library.Slug})");
 					return Task.CompletedTask;
 				}
 
 				// return Task.WhenAll(files.Select(file =>
 				foreach (string file in files)
 				{
-					if (!IsVideo(file) || libraryManager.GetEpisodes().Any(x => x.Path == file))
+					if (!IsVideo(file) || episodes.Any(x => x.Path == file))
 						continue; //return Task.CompletedTask;
 					string relativePath = file.Substring(path.Length);
 					/*return*/ await RegisterFile(file, relativePath, library, cancellationToken);
@@ -128,7 +126,6 @@ namespace Kyoo.Controllers
 			
 			using IServiceScope serviceScope = _serviceProvider.CreateScope();
 			ILibraryManager libraryManager = serviceScope.ServiceProvider.GetService<ILibraryManager>();
-			((DbSet<Library>)libraryManager.GetLibraries()).Attach(library);
 			
 			string patern = _config.GetValue<string>("regex");
 			Regex regex = new Regex(patern, RegexOptions.IgnoreCase);
@@ -145,66 +142,88 @@ namespace Kyoo.Controllers
 			bool isMovie = seasonNumber == -1 && episodeNumber == -1 && absoluteNumber == -1;
 			Show show = await GetShow(libraryManager, showName, showPath, isMovie, library);
 			if (isMovie)
-				libraryManager.Register(await GetMovie(show, path));
+				await libraryManager.RegisterEpisode(await GetMovie(show, path));
 			else
 			{
 				Season season = await GetSeason(libraryManager, show, seasonNumber, library);
 				Episode episode = await GetEpisode(libraryManager, show, season, episodeNumber, absoluteNumber, path, library);
-				libraryManager.Register(episode);
+				await libraryManager.RegisterEpisode(episode);
 			}
-			if (collection != null)
-				libraryManager.Register(collection);
-			libraryManager.RegisterShowLinks(library, collection, show);
-			Console.WriteLine($"Registering episode at: {path}");
-			await libraryManager.SaveChanges();
+
+			await libraryManager.AddShowLink(show, library, collection);
+			Console.WriteLine($"Episode at {path} registered.");
 		}
 
-		private async Task<Collection> GetCollection(ILibraryManager libraryManager, string collectionName, Library library)
+		private async Task<Collection> GetCollection(ILibraryManager libraryManager, 
+			string collectionName, 
+			Library library)
 		{
 			if (string.IsNullOrEmpty(collectionName))
-				return await Task.FromResult<Collection>(null);
-			Collection name = libraryManager.GetCollection(Utility.ToSlug(collectionName));
-			if (name != null)
-				return name;
-			return await _metadataProvider.GetCollectionFromName(collectionName, library);
+				return null;
+			Collection collection = await libraryManager.GetCollection(Utility.ToSlug(collectionName));
+			if (collection != null)
+				return collection;
+			collection = await _metadataProvider.GetCollectionFromName(collectionName, library);
+			await libraryManager.RegisterCollection(collection);
+			return collection;
 		}
 		
-		private async Task<Show> GetShow(ILibraryManager libraryManager, string showTitle, string showPath, bool isMovie, Library library)
+		private async Task<Show> GetShow(ILibraryManager libraryManager, 
+			string showTitle, 
+			string showPath,
+			bool isMovie, 
+			Library library)
 		{
-			Show show = libraryManager.GetShowByPath(showPath);
+			Show show = await libraryManager.GetShowByPath(showPath);
 			if (show != null)
 				return show;
 			show = await _metadataProvider.SearchShow(showTitle, isMovie, library);
 			show.Path = showPath;
 			show.People = await _metadataProvider.GetPeople(show, library);
+			await libraryManager.RegisterShow(show);
 			await _thumbnailsManager.Validate(show.People);
 			await _thumbnailsManager.Validate(show);
 			return show;
 		}
 
-		private async Task<Season> GetSeason(ILibraryManager libraryManager, Show show, long seasonNumber, Library library)
+		private async Task<Season> GetSeason(ILibraryManager libraryManager, 
+			Show show, 
+			long seasonNumber, 
+			Library library)
 		{
 			if (seasonNumber == -1)
 				return default;
-			Season season = libraryManager.GetSeason(show.Slug, seasonNumber);
+			Season season = await libraryManager.GetSeason(show.Slug, seasonNumber);
 			if (season == null)
 			{
 				season = await _metadataProvider.GetSeason(show, seasonNumber, library);
+				await libraryManager.RegisterSeason(season);
 				await _thumbnailsManager.Validate(season);
 			}
 			season.Show = show;
 			return season;
 		}
 		
-		private async Task<Episode> GetEpisode(ILibraryManager libraryManager, Show show, Season season, long episodeNumber, long absoluteNumber, string episodePath, Library library)
+		private async Task<Episode> GetEpisode(ILibraryManager libraryManager, 
+			Show show, 
+			Season season,
+			long episodeNumber,
+			long absoluteNumber, 
+			string episodePath, 
+			Library library)
 		{
-			Episode episode = await _metadataProvider.GetEpisode(show, episodePath, season?.SeasonNumber ?? -1, episodeNumber, absoluteNumber, library);
-			if (season == null)
-				season = await GetSeason(libraryManager, show, episode.SeasonNumber, library);
+			Episode episode = await _metadataProvider.GetEpisode(show,
+				episodePath, 
+				season?.SeasonNumber ?? -1, 
+				episodeNumber,
+				absoluteNumber,
+				library);
+			
+			season ??= await GetSeason(libraryManager, show, episode.SeasonNumber, library);
 			episode.Season = season;
 			if (season == null)
 			{
-				await Console.Error.WriteLineAsync("\tError: You don't have any provider that support absolute epiode numbering. Install one and try again.");
+				await Console.Error.WriteLineAsync("Error: You don't have any provider that support absolute epiode numbering. Install one and try again.");
 				return default;
 			}
 			
diff --git a/Kyoo/Tasks/CreateDatabase.cs b/Kyoo/Tasks/CreateDatabase.cs
index c5345ab4..d4e751dc 100644
--- a/Kyoo/Tasks/CreateDatabase.cs
+++ b/Kyoo/Tasks/CreateDatabase.cs
@@ -58,9 +58,9 @@ namespace Kyoo.Tasks
 			return Task.CompletedTask;
 		}
 
-		public IEnumerable<string> GetPossibleParameters()
+		public Task<IEnumerable<string>> GetPossibleParameters()
 		{
-			return null;
+			return Task.FromResult<IEnumerable<string>>(null);
 		}
 
 		public int? Progress()
diff --git a/Kyoo/Tasks/MetadataLoader.cs b/Kyoo/Tasks/MetadataLoader.cs
index 427eb22e..c66702c5 100644
--- a/Kyoo/Tasks/MetadataLoader.cs
+++ b/Kyoo/Tasks/MetadataLoader.cs
@@ -28,9 +28,9 @@ namespace Kyoo.Tasks
 			return Task.CompletedTask;
 		}
 
-		public IEnumerable<string> GetPossibleParameters()
+		public Task<IEnumerable<string>> GetPossibleParameters()
 		{
-			return null;
+			return Task.FromResult<IEnumerable<string>>(null);
 		}
 
 		public int? Progress()
diff --git a/Kyoo/Tasks/PluginLoader.cs b/Kyoo/Tasks/PluginLoader.cs
index a174caa5..b3f1c064 100644
--- a/Kyoo/Tasks/PluginLoader.cs
+++ b/Kyoo/Tasks/PluginLoader.cs
@@ -24,9 +24,9 @@ namespace Kyoo.Tasks
 			return Task.CompletedTask;
 		}
 
-		public IEnumerable<string> GetPossibleParameters()
+		public Task<IEnumerable<string>> GetPossibleParameters()
 		{
-			return null;
+			return Task.FromResult<IEnumerable<string>>(null);
 		}
 
 		public int? Progress()
diff --git a/Kyoo/Tasks/ReScan.cs b/Kyoo/Tasks/ReScan.cs
index aca39b6d..7ab182a7 100644
--- a/Kyoo/Tasks/ReScan.cs
+++ b/Kyoo/Tasks/ReScan.cs
@@ -114,9 +114,9 @@ namespace Kyoo.Tasks
 			await _thumbnailsManager.Validate(edited, true);
 		}
 
-		public IEnumerable<string> GetPossibleParameters()
+		public Task<IEnumerable<string>> GetPossibleParameters()
 		{
-			return default;
+			return Task.FromResult<IEnumerable<string>>(null);
 		}
 
 		public int? Progress()