Reworking metadata handling and adding it to Collections and Studios

Kyoo.Common/Controllers/IRepository.cs

@@ -590,10 +590,10 @@ namespace Kyoo.Controllers
 		/// <param name="limit">Pagination information (where to start and how many to get)</param>
 		/// <typeparam name="T">The type of metadata to retrieve</typeparam>
 		/// <returns>A filtered list of external ids.</returns>
-		Task<ICollection<MetadataID<T>>> GetMetadataID<T>(Expression<Func<MetadataID<T>, bool>> where = null, 
+		Task<ICollection<MetadataID>> GetMetadataID<T>(Expression<Func<MetadataID, bool>> where = null, 
-			Sort<MetadataID<T>> sort = default,
+			Sort<MetadataID> sort = default,
 			Pagination limit = default)
-			where T : class, IResource;
+			where T : class, IMetadata;
 
 		/// <summary>
 		/// Get a list of external ids that match all filters
@@ -602,11 +602,11 @@ namespace Kyoo.Controllers
 		/// <param name="sort">A sort by expression</param>
 		/// <param name="limit">Pagination information (where to start and how many to get)</param>
 		/// <returns>A filtered list of external ids.</returns>
-		Task<ICollection<MetadataID<T>>> GetMetadataID<T>([Optional] Expression<Func<MetadataID<T>, bool>> where,
+		Task<ICollection<MetadataID>> GetMetadataID<T>([Optional] Expression<Func<MetadataID, bool>> where,
-			Expression<Func<MetadataID<T>, object>> sort,
+			Expression<Func<MetadataID, object>> sort,
 			Pagination limit = default
-		) where T : class, IResource
+		) where T : class, IMetadata
-			=> GetMetadataID(where, new Sort<MetadataID<T>>(sort), limit);
+			=> GetMetadataID<T>(where, new Sort<MetadataID>(sort), limit);
 	}
 	
 	/// <summary>

Kyoo.Common/Controllers/Implementations/LibraryManager.cs

@@ -231,7 +231,12 @@ namespace Kyoo.Controllers
 					.Then(x => l.Collections = x), 
 				
 				
-				(Collection c, nameof(Library.Shows)) => ShowRepository
+				(Collection c, nameof(Collection.ExternalIDs)) => SetRelation(c, 
+					ProviderRepository.GetMetadataID<Collection>(x => x.ResourceID == obj.ID),
+					(x, y) => x.ExternalIDs = y,
+					(x, y) => { x.ResourceID = y.ID; }),
+				
+				(Collection c, nameof(Collection.Shows)) => ShowRepository
 					.GetAll(x => x.Collections.Any(y => y.ID == obj.ID))
 					.Then(x => c.Shows = x), 
 				
@@ -241,9 +246,9 @@ namespace Kyoo.Controllers
 				
 				
 				(Show s, nameof(Show.ExternalIDs)) => SetRelation(s, 
-					ProviderRepository.GetMetadataID<Show>(x => x.FirstID == obj.ID),
+					ProviderRepository.GetMetadataID<Show>(x => x.ResourceID == obj.ID),
 					(x, y) => x.ExternalIDs = y,
-					(x, y) => { x.First = y; x.FirstID = y.ID; }),
+					(x, y) => { x.ResourceID = y.ID; }),
 				
 				(Show s, nameof(Show.Genres)) => GenreRepository
 					.GetAll(x => x.Shows.Any(y => y.ID == obj.ID))
@@ -281,9 +286,9 @@ namespace Kyoo.Controllers
 				
 				
 				(Season s, nameof(Season.ExternalIDs)) => SetRelation(s, 
-					ProviderRepository.GetMetadataID<Season>(x => x.FirstID == obj.ID),
+					ProviderRepository.GetMetadataID<Season>(x => x.ResourceID == obj.ID),
 					(x, y) => x.ExternalIDs = y,
-					(x, y) => { x.First = y; x.FirstID = y.ID; }),
+					(x, y) => { x.ResourceID = y.ID; }),
 				
 				(Season s, nameof(Season.Episodes)) => SetRelation(s, 
 					EpisodeRepository.GetAll(x => x.Season.ID == obj.ID),
@@ -300,9 +305,9 @@ namespace Kyoo.Controllers
 				
 				
 				(Episode e, nameof(Episode.ExternalIDs)) => SetRelation(e, 
-					ProviderRepository.GetMetadataID<Episode>(x => x.FirstID == obj.ID), 
+					ProviderRepository.GetMetadataID<Episode>(x => x.ResourceID == obj.ID), 
 					(x, y) => x.ExternalIDs = y,
-					(x, y) => { x.First = y; x.FirstID = y.ID; }),
+					(x, y) => { x.ResourceID = y.ID; }),
 				
 				(Episode e, nameof(Episode.Tracks)) => SetRelation(e, 
 					TrackRepository.GetAll(x => x.Episode.ID == obj.ID),
@@ -344,11 +349,16 @@ namespace Kyoo.Controllers
 					.GetAll(x => x.Studio.ID == obj.ID)
 					.Then(x => s.Shows = x),
 				
+				(Studio s, nameof(Studio.ExternalIDs)) => SetRelation(s, 
+					ProviderRepository.GetMetadataID<Studio>(x => x.ResourceID == obj.ID),
+					(x, y) => x.ExternalIDs = y,
+					(x, y) => { x.ResourceID = y.ID; }),
+				
 				
 				(People p, nameof(People.ExternalIDs)) => SetRelation(p, 
-					ProviderRepository.GetMetadataID<People>(x => x.FirstID == obj.ID),
+					ProviderRepository.GetMetadataID<People>(x => x.ResourceID == obj.ID),
 					(x, y) => x.ExternalIDs = y,
-					(x, y) => { x.First = y; x.FirstID = y.ID; }),
+					(x, y) => { x.ResourceID = y.ID; }),
 				
 				(People p, nameof(People.Roles)) => PeopleRepository
 					.GetFromPeople(obj.ID)

Kyoo.Common/Models/Link.cs

@@ -92,7 +92,7 @@ namespace Kyoo.Models
 			get
 			{
 				return x => new {First = x.FirstID, Second = x.SecondID};
-			}	
+			}
 		}
 	}
 	
@@ -157,7 +157,7 @@ namespace Kyoo.Models
 			get
 			{
 				return x => new {First = x.FirstID, Second = x.SecondID};
-			}	
+			}
 		}
 	}
 }

Kyoo.Common/Models/MetadataID.cs

@@ -1,15 +1,34 @@
 using System;
 using System.Linq.Expressions;
+using Kyoo.Models.Attributes;
 
 namespace Kyoo.Models
 {
 	/// <summary>
 	/// ID and link of an item on an external provider.
 	/// </summary>
-	/// <typeparam name="T"></typeparam>
+	public class MetadataID
-	public class MetadataID<T> : Link<T, Provider>
-		where T : class, IResource
 	{
+		/// <summary>
+		/// The ID of the resource which possess the metadata.
+		/// </summary>
+		[SerializeIgnore] public int ResourceID { get; set; }
+		
+		/// <summary>
+		/// The name of the resource type. This is only used internally to discriminate types.  
+		/// </summary>
+		[SerializeIgnore] public string ResourceType { get; set; }
+		
+		/// <summary>
+		/// The ID of the provider.
+		/// </summary>
+		[SerializeIgnore] public int ProviderID { get; set; }
+		
+		/// <summary>
+		/// The provider that can do something with this ID.
+		/// </summary>
+		public Provider Provider { get; set; }
+		
 		/// <summary>
 		/// The ID of the resource on the external provider.
 		/// </summary>
@@ -20,20 +39,14 @@ namespace Kyoo.Models
 		/// </summary>
 		public string Link { get; set; }
 
-		/// <summary>
-		/// A shortcut to access the provider of this metadata.
-		/// Unlike the <see cref="Link{T, T2}.Second"/> property, this is serializable.
-		/// </summary>
-		public Provider Provider => Second;
-		
 		/// <summary>
 		/// The expression to retrieve the unique ID of a MetadataID. This is an aggregate of the two resources IDs.
 		/// </summary>
-		public new static Expression<Func<MetadataID<T>, object>> PrimaryKey
+		public static Expression<Func<MetadataID, object>> PrimaryKey
 		{
 			get
 			{
-				return x => new {First = x.FirstID, Second = x.SecondID};
+				return x => new {First = x.ResourceID, Second = x.ProviderID, Type = x.ResourceType};
 			}	
 		}
 	}

Kyoo.Common/Models/Resources/Collection.cs

@@ -8,7 +8,7 @@ namespace Kyoo.Models
 	/// A class representing collections of <see cref="Show"/>.
 	/// A collection can also be stored in a <see cref="Library"/>.
 	/// </summary>
-	public class Collection : IResource
+	public class Collection : IResource, IMetadata
 	{
 		/// <inheritdoc />
 		public int ID { get; set; }
@@ -42,6 +42,9 @@ namespace Kyoo.Models
 		/// The list of libraries that contains this collection.
 		/// </summary>
 		[LoadableRelation] public ICollection<Library> Libraries { get; set; }
+		
+		/// <inheritdoc />
+		public ICollection<MetadataID> ExternalIDs { get; set; }
 
 #if ENABLE_INTERNAL_LINKS
 		

Kyoo.Common/Models/Resources/Episode.cs

@@ -10,7 +10,7 @@ namespace Kyoo.Models
 	/// <summary>
 	/// A class to represent a single show's episode.
 	/// </summary>
-	public class Episode : IResource
+	public class Episode : IResource, IMetadata
 	{
 		/// <inheritdoc />
 		public int ID { get; set; }
@@ -121,10 +121,8 @@ namespace Kyoo.Models
 		/// </summary>
 		public DateTime? ReleaseDate { get; set; }
 
-		/// <summary>
+		/// <inheritdoc />
-		/// The link to metadata providers that this episode has. See <see cref="MetadataID{T}"/> for more information.
+		public ICollection<MetadataID> ExternalIDs { get; set; }
-		/// </summary>
-		[EditableRelation] [LoadableRelation] public ICollection<MetadataID<Episode>> ExternalIDs { get; set; }
 
 		/// <summary>
 		/// The list of tracks this episode has. This lists video, audio and subtitles available.

Kyoo.Common/Models/Resources/Interfaces/IMetadata.cs

@@ -0,0 +1,16 @@
+using System.Collections.Generic;
+using Kyoo.Models.Attributes;
+
+namespace Kyoo.Models
+{
+	/// <summary>
+	/// An interface applied to resources containing external metadata.
+	/// </summary>
+	public interface IMetadata
+	{
+		/// <summary>
+		/// The link to metadata providers that this show has. See <see cref="MetadataID"/> for more information.
+		/// </summary>
+		[EditableRelation] [LoadableRelation] public ICollection<MetadataID> ExternalIDs { get; set; }
+	}
+}

Kyoo.Common/Models/Resources/People.cs

@@ -6,7 +6,7 @@ namespace Kyoo.Models
 	/// <summary>
 	/// An actor, voice actor, writer, animator, somebody who worked on a <see cref="Show"/>. 
 	/// </summary>
-	public class People : IResource
+	public class People : IResource, IMetadata
 	{
 		/// <inheritdoc />
 		public int ID { get; set; }
@@ -26,10 +26,8 @@ namespace Kyoo.Models
 		/// </summary>
 		[SerializeAs("{HOST}/api/people/{Slug}/poster")] public string Poster { get; set; }
 		
-		/// <summary>
+		/// <inheritdoc />
-        /// The link to metadata providers that this person has. See <see cref="MetadataID{T}"/> for more information.
+		public ICollection<MetadataID> ExternalIDs { get; set; }
-        /// </summary>
-		[EditableRelation] [LoadableRelation] public ICollection<MetadataID<People>> ExternalIDs { get; set; }
 		
 		/// <summary>
 		/// The list of roles this person has played in. See <see cref="PeopleRole"/> for more information.

Kyoo.Common/Models/Resources/Season.cs

@@ -10,7 +10,7 @@ namespace Kyoo.Models
 	/// <summary>
 	/// A season of a <see cref="Show"/>. 
 	/// </summary>
-	public class Season : IResource
+	public class Season : IResource, IMetadata
 	{
 		/// <inheritdoc />
 		public int ID  { get; set; }
@@ -81,10 +81,8 @@ namespace Kyoo.Models
 		/// </summary>
 		[SerializeAs("{HOST}/api/seasons/{Slug}/thumb")] public string Poster { get; set; }
 		
-		/// <summary>
+		/// <inheritdoc />
-		/// The link to metadata providers that this episode has. See <see cref="MetadataID{T}"/> for more information.
+		public ICollection<MetadataID> ExternalIDs { get; set; }
-		/// </summary>
-		[EditableRelation] [LoadableRelation] public ICollection<MetadataID<Season>> ExternalIDs { get; set; }
 
 		/// <summary>
 		/// The list of episodes that this season contains.

Kyoo.Common/Models/Resources/Show.cs

@@ -11,7 +11,7 @@ namespace Kyoo.Models
 	/// <summary>
 	/// A series or a movie.
 	/// </summary>
-	public class Show : IResource, IOnMerge
+	public class Show : IResource, IMetadata, IOnMerge
 	{
 		/// <inheritdoc />
 		public int ID { get; set; }
@@ -89,11 +89,9 @@ namespace Kyoo.Models
 		/// </summary>
 		public bool IsMovie { get; set; }
 
-		/// <summary>
+		/// <inheritdoc />
-		/// The link to metadata providers that this show has. See <see cref="MetadataID{T}"/> for more information.
+		public ICollection<MetadataID> ExternalIDs { get; set; }
-		/// </summary>
+
-		[EditableRelation] [LoadableRelation] public ICollection<MetadataID<Show>> ExternalIDs { get; set; }
-		
 		/// <summary>
 		/// The ID of the Studio that made this show.
 		/// </summary>
@@ -157,19 +155,16 @@ namespace Kyoo.Models
 		/// </summary>
 		/// <remarks>This method will never return anything if the <see cref="ExternalIDs"/> are not loaded.</remarks>
 		/// <param name="provider">The slug of the provider</param>
-		/// <returns>The <see cref="MetadataID{T}.DataID"/> field of the asked provider.</returns>
+		/// <returns>The <see cref="MetadataID.DataID"/> field of the asked provider.</returns>
 		[CanBeNull]
 		public string GetID(string provider)
 		{
-			return ExternalIDs?.FirstOrDefault(x => x.Second.Slug == provider)?.DataID;
+			return ExternalIDs?.FirstOrDefault(x => x.Provider.Slug == provider)?.DataID;
 		}
 
 		/// <inheritdoc />
 		public void OnMerge(object merged)
 		{
-			if (ExternalIDs != null)
-				foreach (MetadataID<Show> id in ExternalIDs)
-					id.First = this;
 			if (People != null)
 				foreach (PeopleRole link in People)
 					link.Show = this;

Kyoo.Common/Models/Resources/Studio.cs

@@ -6,7 +6,7 @@ namespace Kyoo.Models
 	/// <summary>
 	/// A studio that make shows.
 	/// </summary>
-	public class Studio : IResource
+	public class Studio : IResource, IMetadata
 	{
 		/// <inheritdoc />
 		public int ID { get; set; }
@@ -24,6 +24,9 @@ namespace Kyoo.Models
 		/// </summary>
 		[LoadableRelation] public ICollection<Show> Shows { get; set; }
 
+		/// <inheritdoc />
+		public ICollection<MetadataID> ExternalIDs { get; set; }
+		
 		/// <summary>
 		/// Create a new, empty, <see cref="Studio"/>.
 		/// </summary>

Kyoo.CommonAPI/DatabaseContext.cs

@@ -61,6 +61,10 @@ namespace Kyoo
 		/// </summary>
 		public DbSet<Provider> Providers { get; set; }
 		/// <summary>
+		/// All metadata ids, not discriminated by type. See <see cref="MetadataID"/>.
+		/// </summary>
+		public DbSet<MetadataID> MetadataIDs { get; set; }
+		/// <summary>
 		/// The list of registered users.
 		/// </summary>
 		public DbSet<User> Users { get; set; }
@@ -83,17 +87,6 @@ namespace Kyoo
 		/// </remarks>
 		public DbSet<LibraryItem> LibraryItems { get; set; }
 
-		/// <summary>
-		/// Get all metadataIDs (ExternalIDs) of a given resource. See <see cref="MetadataID{T}"/>.
-		/// </summary>
-		/// <typeparam name="T">The metadata of this type will be returned.</typeparam>
-		/// <returns>A queryable of metadata ids for a type.</returns>
-		public DbSet<MetadataID<T>> MetadataIds<T>()
-			where T : class, IResource
-		{
-			return Set<MetadataID<T>>();
-		}
-		
 		/// <summary>
 		/// Get a generic link between two resource types.
 		/// </summary>
@@ -132,6 +125,22 @@ namespace Kyoo
 			optionsBuilder.UseQueryTrackingBehavior(QueryTrackingBehavior.NoTracking);
 		}
 
+		/// <summary>
+		/// Build the metadata model for the given type.
+		/// </summary>
+		/// <param name="modelBuilder">The database model builder</param>
+		/// <typeparam name="T">The type to add metadata to.</typeparam>
+		private void _HasMetadata<T>(ModelBuilder modelBuilder)
+			where T : class, IMetadata
+		{
+			modelBuilder.Entity<T>()
+				.HasMany(x => x.ExternalIDs)
+				.WithOne()
+				.HasForeignKey(x => x.ResourceID)
+				.OnDelete(DeleteBehavior.Cascade);
+		}
+		
+		
 		/// <summary>
 		/// Set database parameters to support every types of Kyoo.
 		/// </summary>
@@ -234,43 +243,21 @@ namespace Kyoo
 						.WithMany(x => x.ShowLinks),
 					y => y.HasKey(Link<User, Show>.PrimaryKey));
 
-			modelBuilder.Entity<MetadataID<Show>>()
+			modelBuilder.Entity<MetadataID>()
-				.HasKey(MetadataID<Show>.PrimaryKey);
+				.HasKey(MetadataID.PrimaryKey);
-			modelBuilder.Entity<MetadataID<Show>>()
+			modelBuilder.Entity<MetadataID>()
-				.HasOne(x => x.First)
+				.Property(x => x.ResourceType)
-				.WithMany(x => x.ExternalIDs)
+				.IsRequired();
-				.OnDelete(DeleteBehavior.Cascade);
+			modelBuilder.Entity<MetadataID>()
-			modelBuilder.Entity<MetadataID<Season>>()
+				.HasDiscriminator(x => x.ResourceType);
-				.HasKey(MetadataID<Season>.PrimaryKey);
-			modelBuilder.Entity<MetadataID<Season>>()
-				.HasOne(x => x.First)
-				.WithMany(x => x.ExternalIDs)
-				.OnDelete(DeleteBehavior.Cascade);
-			modelBuilder.Entity<MetadataID<Episode>>()
-				.HasKey(MetadataID<Episode>.PrimaryKey);
-			modelBuilder.Entity<MetadataID<Episode>>()
-				.HasOne(x => x.First)
-				.WithMany(x => x.ExternalIDs)
-				.OnDelete(DeleteBehavior.Cascade);
-			modelBuilder.Entity<MetadataID<People>>()
-				.HasKey(MetadataID<People>.PrimaryKey);
-			modelBuilder.Entity<MetadataID<People>>()
-				.HasOne(x => x.First)
-				.WithMany(x => x.ExternalIDs)
-				.OnDelete(DeleteBehavior.Cascade);
-			
-			
-			modelBuilder.Entity<MetadataID<Show>>().HasOne(x => x.Second).WithMany()
-				.OnDelete(DeleteBehavior.Cascade);
-			modelBuilder.Entity<MetadataID<Season>>().HasOne(x => x.Second).WithMany()
-				.OnDelete(DeleteBehavior.Cascade);
-			modelBuilder.Entity<MetadataID<Episode>>().HasOne(x => x.Second).WithMany()
-				.OnDelete(DeleteBehavior.Cascade);
-			modelBuilder.Entity<MetadataID<People>>().HasOne(x => x.Second).WithMany()
-				.OnDelete(DeleteBehavior.Cascade);
-			modelBuilder.Entity<MetadataID<Show>>().HasOne(x => x.Second).WithMany()
-				.OnDelete(DeleteBehavior.Cascade);
 
+			_HasMetadata<Collection>(modelBuilder);
+			_HasMetadata<Show>(modelBuilder);
+			_HasMetadata<Season>(modelBuilder);
+			_HasMetadata<Episode>(modelBuilder);
+			_HasMetadata<People>(modelBuilder);
+			_HasMetadata<Studio>(modelBuilder);
+			
 			modelBuilder.Entity<WatchedEpisode>()
 				.HasKey(x => new {First = x.FirstID, Second = x.SecondID});
 

Kyoo.Tests/Database/RepositoryActivator.cs

@@ -22,9 +22,9 @@ namespace Kyoo.Tests
 			
 			ProviderRepository provider = new(_database);
 			LibraryRepository library = new(_database, provider);
-			CollectionRepository collection = new(_database);
+			CollectionRepository collection = new(_database, provider);
 			GenreRepository genre = new(_database);
-			StudioRepository studio = new(_database);
+			StudioRepository studio = new(_database, provider);
 			PeopleRepository people = new(_database, provider, 
 				new Lazy<IShowRepository>(() => LibraryManager.ShowRepository));
 			ShowRepository show = new(_database, studio, people, genre, provider);

Kyoo.Tests/Database/SpecificTests/ShowTests.cs

@@ -149,10 +149,9 @@ namespace Kyoo.Tests.Database
 			Show value = await _repository.Get(TestSample.Get<Show>().Slug);
 			value.ExternalIDs = new[]
 			{
-				new MetadataID<Show>()
+				new MetadataID
 				{
-					First = value,
+					Provider = new Provider("test", "test.png"),
-					Second = new Provider("test", "test.png"),
 					DataID = "1234"
 				}
 			};
@@ -160,19 +159,19 @@ namespace Kyoo.Tests.Database
 			
 			Assert.Equal(value.Slug, edited.Slug);
 			Assert.Equal(
-				value.ExternalIDs.Select(x => new {x.DataID, x.Second.Slug}), 
+				value.ExternalIDs.Select(x => new {x.DataID, x.Provider.Slug}), 
-				edited.ExternalIDs.Select(x => new {x.DataID, x.Second.Slug}));
+				edited.ExternalIDs.Select(x => new {x.DataID, x.Provider.Slug}));
 		
 			await using DatabaseContext database = Repositories.Context.New();
 			Show show = await database.Shows
 				.Include(x => x.ExternalIDs)
-				.ThenInclude(x => x.Second)
+				.ThenInclude(x => x.Provider)
 				.FirstAsync();
 			
 			Assert.Equal(value.Slug, show.Slug);
 			Assert.Equal(
-				value.ExternalIDs.Select(x => new {x.DataID, x.Second.Slug}), 
+				value.ExternalIDs.Select(x => new {x.DataID, x.Provider.Slug}), 
-				show.ExternalIDs.Select(x => new {x.DataID, x.Second.Slug}));
+				show.ExternalIDs.Select(x => new {x.DataID, x.Provider.Slug}));
 		}
 		
 		[Fact]
@@ -209,10 +208,9 @@ namespace Kyoo.Tests.Database
 			expected.Slug = "created-relation-test";
 			expected.ExternalIDs = new[]
 			{
-				new MetadataID<Show>
+				new MetadataID
 				{
-					First = expected,
+					Provider = new Provider("provider", "provider.png"),
-					Second = new Provider("provider", "provider.png"),
 					DataID = "ID"
 				}
 			};

Kyoo.TheMovieDb/Convertors.cs

@@ -48,9 +48,9 @@ namespace Kyoo.TheMovieDb
 					.ToArray(),
 				ExternalIDs = new []
 				{
-					new MetadataID<Show>
+					new MetadataID
 					{
-						Second = provider,
+						Provider = provider,
 						Link = $"https://www.themoviedb.org/movie/{movie.Id}",
 						DataID = movie.Id.ToString()
 					}
@@ -94,9 +94,9 @@ namespace Kyoo.TheMovieDb
 					.ToArray(),
 				ExternalIDs = new []
 				{
-					new MetadataID<Show>
+					new MetadataID
 					{
-						Second = provider,
+						Provider = provider,
 						Link = $"https://www.themoviedb.org/movie/{tv.Id}",
 						DataID = tv.Id.ToString()
 					}
@@ -145,9 +145,9 @@ namespace Kyoo.TheMovieDb
 				IsMovie = true,
 				ExternalIDs = new []
 				{
-					new MetadataID<Show>
+					new MetadataID
 					{
-						Second = provider,
+						Provider = provider,
 						Link = $"https://www.themoviedb.org/movie/{movie.Id}",
 						DataID = movie.Id.ToString()
 					}
@@ -178,9 +178,9 @@ namespace Kyoo.TheMovieDb
 				IsMovie = true,
 				ExternalIDs = new []
 				{
-					new MetadataID<Show>
+					new MetadataID
 					{
-						Second = provider,
+						Provider = provider,
 						Link = $"https://www.themoviedb.org/movie/{tv.Id}",
 						DataID = tv.Id.ToString()
 					}
@@ -205,9 +205,9 @@ namespace Kyoo.TheMovieDb
 					Poster = cast.ProfilePath != null ? $"https://image.tmdb.org/t/p/original{cast.ProfilePath}" : null,
 					ExternalIDs = new[]
 					{
-						new MetadataID<People>
+						new MetadataID
 						{
-							Second = provider,
+							Provider = provider,
 							DataID = cast.Id.ToString(),
 							Link = $"https://www.themoviedb.org/person/{cast.Id}"
 						}
@@ -235,9 +235,9 @@ namespace Kyoo.TheMovieDb
 					Poster = cast.ProfilePath != null ? $"https://image.tmdb.org/t/p/original{cast.ProfilePath}" : null,
 					ExternalIDs = new[]
 					{
-						new MetadataID<People>
+						new MetadataID
 						{
-							Second = provider,
+							Provider = provider,
 							DataID = cast.Id.ToString(),
 							Link = $"https://www.themoviedb.org/person/{cast.Id}"
 						}
@@ -265,9 +265,9 @@ namespace Kyoo.TheMovieDb
 					Poster = crew.ProfilePath != null ? $"https://image.tmdb.org/t/p/original{crew.ProfilePath}" : null,
 					ExternalIDs = new[]
 					{
-						new MetadataID<People>
+						new MetadataID
 						{
-							Second = provider,
+							Provider = provider,
 							DataID = crew.Id.ToString(),
 							Link = $"https://www.themoviedb.org/person/{crew.Id}"
 						}

Kyoo.TheTvdb/Convertors.cs

@@ -58,11 +58,11 @@ namespace Kyoo.TheTvdb
 				Poster = result.Poster != null ? $"https://www.thetvdb.com{result.Poster}" : null,
 				ExternalIDs = new[]
 				{
-					new MetadataID<Show>
+					new MetadataID
 					{
 						DataID = result.Id.ToString(),
 						Link = $"https://www.thetvdb.com/series/{result.Slug}",
-						Second = provider
+						Provider = provider
 					}
 				}
 			};
@@ -89,11 +89,11 @@ namespace Kyoo.TheTvdb
 				Genres = series.Genre.Select(y => new Genre(y)).ToList(),
 				ExternalIDs = new[]
 				{
-					new MetadataID<Show>
+					new MetadataID
 					{
 						DataID = series.Id.ToString(),
 						Link = $"https://www.thetvdb.com/series/{series.Slug}",
-						Second = provider
+						Provider = provider
 					}
 				}
 			};
@@ -116,11 +116,11 @@ namespace Kyoo.TheTvdb
 					Poster = actor.Image != null ? $"https://www.thetvdb.com/banners/{actor.Image}" : null,
 					ExternalIDs = new []
 					{
-						new MetadataID<People>()
+						new MetadataID
 						{
 							DataID = actor.Id.ToString(),
 							Link = $"https://www.thetvdb.com/people/{actor.Id}",
-							Second = provider
+							Provider = provider
 						}
 					}
 				},
@@ -147,11 +147,11 @@ namespace Kyoo.TheTvdb
 				Thumb = episode.Filename != null ? $"https://www.thetvdb.com/banners/{episode.Filename}" : null,
 				ExternalIDs = new[]
 				{
-					new MetadataID<Episode>
+					new MetadataID
 					{
 						DataID = episode.Id.ToString(),
 						Link = $"https://www.thetvdb.com/series/{episode.SeriesId}/episodes/{episode.Id}",
-						Second = provider
+						Provider = provider
 					}
 				}
 			};

Kyoo/Controllers/Repositories/CollectionRepository.cs

@@ -18,6 +18,11 @@ namespace Kyoo.Controllers
 		/// </summary>
 		private readonly DatabaseContext _database;
 		
+		/// <summary>
+		/// A provider repository to handle externalID creation and deletion
+		/// </summary>
+		private readonly IProviderRepository _providers;
+		
 		/// <inheritdoc />
 		protected override Expression<Func<Collection, object>> DefaultSort => x => x.Name;
 
@@ -25,10 +30,12 @@ namespace Kyoo.Controllers
 		/// Create a new <see cref="CollectionRepository"/>.
 		/// </summary>
 		/// <param name="database">The database handle to use</param>
-		public CollectionRepository(DatabaseContext database)
+		/// /// <param name="providers">A provider repository</param>
+		public CollectionRepository(DatabaseContext database, IProviderRepository providers)
 			: base(database)
 		{
 			_database = database;
+			_providers = providers;
 		}
 
 		/// <inheritdoc />
@@ -46,9 +53,35 @@ namespace Kyoo.Controllers
 		{
 			await base.Create(obj);
 			_database.Entry(obj).State = EntityState.Added;
+			obj.ExternalIDs.ForEach(x => _database.Entry(x).State = EntityState.Added);
 			await _database.SaveChangesAsync($"Trying to insert a duplicated collection (slug {obj.Slug} already exists).");
 			return obj;
 		}
+		
+		/// <inheritdoc />
+		protected override async Task Validate(Collection resource)
+		{
+			await base.Validate(resource);
+			await resource.ExternalIDs.ForEachAsync(async x => 
+			{ 
+				x.Provider = await _providers.CreateIfNotExists(x.Provider);
+				x.ProviderID = x.Provider.ID;
+				x.ResourceType = nameof(Collection);
+				_database.Entry(x.Provider).State = EntityState.Detached;
+			});
+		}
+		
+		/// <inheritdoc />
+		protected override async Task EditRelations(Collection resource, Collection changed, bool resetOld)
+		{
+			if (changed.ExternalIDs != null || resetOld)
+			{
+				await Database.Entry(resource).Collection(x => x.ExternalIDs).LoadAsync();
+				resource.ExternalIDs = changed.ExternalIDs;
+			}
+
+			await base.EditRelations(resource, changed, resetOld);
+		}
 
 		/// <inheritdoc />
 		public override async Task Delete(Collection obj)

Kyoo/Controllers/Repositories/EpisodeRepository.cs

@@ -160,9 +160,10 @@ namespace Kyoo.Controllers
 			await base.Validate(resource);
 			await resource.ExternalIDs.ForEachAsync(async x => 
 			{ 
-				x.Second = await _providers.CreateIfNotExists(x.Second);
+				x.Provider = await _providers.CreateIfNotExists(x.Provider);
-				x.SecondID = x.Second.ID;
+				x.ProviderID = x.Provider.ID;
-				_database.Entry(x.Second).State = EntityState.Detached;
+				x.ResourceType = nameof(Episode);
+				_database.Entry(x.Provider).State = EntityState.Detached;
 			});
 		}
 		

Kyoo/Controllers/Repositories/PeopleRepository.cs

@@ -73,9 +73,10 @@ namespace Kyoo.Controllers
 			await base.Validate(resource);
 			await resource.ExternalIDs.ForEachAsync(async id =>
 			{
-				id.Second = await _providers.CreateIfNotExists(id.Second);
+				id.Provider = await _providers.CreateIfNotExists(id.Provider);
-				id.SecondID = id.Second.ID;
+				id.ProviderID = id.Provider.ID;
-				_database.Entry(id.Second).State = EntityState.Detached;
+				id.ResourceType = nameof(People);
+				_database.Entry(id.Provider).State = EntityState.Detached;
 			});
 			await resource.Roles.ForEachAsync(async role =>
 			{

Kyoo/Controllers/Repositories/ProviderRepository.cs

@@ -9,21 +9,18 @@ using Microsoft.EntityFrameworkCore;
 namespace Kyoo.Controllers
 {
 	/// <summary>
-	/// A local repository to handle providers.
+	///     A local repository to handle providers.
 	/// </summary>
 	public class ProviderRepository : LocalRepository<Provider>, IProviderRepository
 	{
 		/// <summary>
-		/// The database handle
+		///     The database handle
 		/// </summary>
 		private readonly DatabaseContext _database;
-		
-		/// <inheritdoc />
-		protected override Expression<Func<Provider, object>> DefaultSort => x => x.Slug;
 
 
 		/// <summary>
-		/// Create a new <see cref="ProviderRepository"/>.
+		///     Create a new <see cref="ProviderRepository" />.
 		/// </summary>
 		/// <param name="database">The database handle</param>
 		public ProviderRepository(DatabaseContext database)
@@ -32,6 +29,9 @@ namespace Kyoo.Controllers
 			_database = database;
 		}
 
+		/// <inheritdoc />
+		protected override Expression<Func<Provider, object>> DefaultSort => x => x.Slug;
+
 		/// <inheritdoc />
 		public override async Task<ICollection<Provider>> Search(string query)
 		{
@@ -47,7 +47,8 @@ namespace Kyoo.Controllers
 		{
 			await base.Create(obj);
 			_database.Entry(obj).State = EntityState.Added;
-			await _database.SaveChangesAsync($"Trying to insert a duplicated provider (slug {obj.Slug} already exists).");
+			await _database.SaveChangesAsync("Trying to insert a duplicated provider " +
+				$"(slug {obj.Slug} already exists).");
 			return obj;
 		}
 
@@ -56,20 +57,24 @@ namespace Kyoo.Controllers
 		{
 			if (obj == null)
 				throw new ArgumentNullException(nameof(obj));
-			
+
 			_database.Entry(obj).State = EntityState.Deleted;
 			await _database.SaveChangesAsync();
 		}
 
 		/// <inheritdoc />
-		public Task<ICollection<MetadataID<T>>> GetMetadataID<T>(Expression<Func<MetadataID<T>, bool>> where = null,
+		public Task<ICollection<MetadataID>> GetMetadataID<T>(Expression<Func<MetadataID, bool>> where = null,
-			Sort<MetadataID<T>> sort = default, 
+			Sort<MetadataID> sort = default,
 			Pagination limit = default)
-			where T : class, IResource
+			where T : class, IMetadata
 		{
-			return ApplyFilters(_database.MetadataIds<T>().Include(y => y.Second),
+			string discriminator = typeof(T).Name;
-				x => _database.MetadataIds<T>().FirstOrDefaultAsync(y => y.FirstID == x),
+			return ApplyFilters(_database.MetadataIDs
-				x => x.FirstID,
+					.Include(y => y.Provider)
+					.Where(x => x.ResourceType == discriminator),
+				x => _database.MetadataIDs.FirstOrDefaultAsync(y => y.ResourceID == x
+					&& y.ResourceType == discriminator),
+				x => x.ResourceID,
 				where,
 				sort,
 				limit);

Kyoo/Controllers/Repositories/SeasonRepository.cs

@@ -106,9 +106,10 @@ namespace Kyoo.Controllers
 			await base.Validate(resource);
 			await resource.ExternalIDs.ForEachAsync(async id =>
 			{
-				id.Second = await _providers.CreateIfNotExists(id.Second);
+				id.Provider = await _providers.CreateIfNotExists(id.Provider);
-				id.SecondID = id.Second.ID;
+				id.ProviderID = id.Provider.ID;
-				_database.Entry(id.Second).State = EntityState.Detached;
+				id.ResourceType = nameof(Season);
+				_database.Entry(id.Provider).State = EntityState.Detached;
 			});
 		}
 

Kyoo/Controllers/Repositories/ShowRepository.cs

@@ -101,9 +101,10 @@ namespace Kyoo.Controllers
 			});
 			await resource.ExternalIDs.ForEachAsync(async id =>
 			{
-				id.Second = await _providers.CreateIfNotExists(id.Second);
+				id.Provider = await _providers.CreateIfNotExists(id.Provider);
-				id.SecondID = id.Second.ID;
+				id.ProviderID = id.Provider.ID;
-				_database.Entry(id.Second).State = EntityState.Detached;
+				id.ResourceType = nameof(Show);
+				_database.Entry(id.Provider).State = EntityState.Detached;
 			});
 			await resource.People.ForEachAsync(async role =>
 			{

Kyoo/Controllers/Repositories/StudioRepository.cs

@@ -18,6 +18,11 @@ namespace Kyoo.Controllers
 		/// </summary>
 		private readonly DatabaseContext _database;
 		
+		/// <summary>
+		/// A provider repository to handle externalID creation and deletion
+		/// </summary>
+		private readonly IProviderRepository _providers;
+		
 		/// <inheritdoc />
 		protected override Expression<Func<Studio, object>> DefaultSort => x => x.Name;
 
@@ -26,10 +31,12 @@ namespace Kyoo.Controllers
 		/// Create a new <see cref="StudioRepository"/>.
 		/// </summary>
 		/// <param name="database">The database handle</param>
-		public StudioRepository(DatabaseContext database)
+		/// <param name="providers">A provider repository</param>
+		public StudioRepository(DatabaseContext database, IProviderRepository providers)
 			: base(database)
 		{
 			_database = database;
+			_providers = providers;
 		}
 		
 		/// <inheritdoc />
@@ -50,6 +57,31 @@ namespace Kyoo.Controllers
 			await _database.SaveChangesAsync($"Trying to insert a duplicated studio (slug {obj.Slug} already exists).");
 			return obj;
 		}
+		
+		/// <inheritdoc />
+		protected override async Task Validate(Studio resource)
+		{
+			await base.Validate(resource);
+			await resource.ExternalIDs.ForEachAsync(async x => 
+			{ 
+				x.Provider = await _providers.CreateIfNotExists(x.Provider);
+				x.ProviderID = x.Provider.ID;
+				x.ResourceType = nameof(Studio);
+				_database.Entry(x.Provider).State = EntityState.Detached;
+			});
+		}
+		
+		/// <inheritdoc />
+		protected override async Task EditRelations(Studio resource, Studio changed, bool resetOld)
+		{
+			if (changed.ExternalIDs != null || resetOld)
+			{
+				await Database.Entry(resource).Collection(x => x.ExternalIDs).LoadAsync();
+				resource.ExternalIDs = changed.ExternalIDs;
+			}
+
+			await base.EditRelations(resource, changed, resetOld);
+		}
 
 		/// <inheritdoc />
 		public override async Task Delete(Studio obj)