feat(backend): expose the first cover track ids of playlists and albums

backend/Musify.Application/Albums/GetAlbumById.cs

@@ -17,13 +17,22 @@ namespace Musify.Application.Albums
             var album = await database.UserAlbums
                 .AsNoTracking()
                 .Where(a => a.Id == request.Id)
-                .Select(a => new { Album = a, TrackCount = a.AlbumTracks.Count })
+                .Select(a => new
+                {
+                    Album = a,
+                    TrackCount = a.AlbumTracks.Count,
+                    CoverTrackIds = a.AlbumTracks
+                        .OrderBy(albumTrack => albumTrack.TrackNumber)
+                        .Take(AlbumApplicationResponse.CoverTrackCount)
+                        .Select(albumTrack => albumTrack.TrackId)
+                        .ToList()
+                })
                 .SingleOrDefaultAsync(cancellationToken);
 
             if (album is null)
                 return Error.NotFound();
 
-            return AlbumApplicationResponse.FromEntity(album.Album, album.TrackCount);
+            return AlbumApplicationResponse.FromEntity(album.Album, album.TrackCount, album.CoverTrackIds);
         }
     }
 }

backend/Musify.Application/Albums/GetAlbums.cs

@@ -31,11 +31,20 @@ namespace Musify.Application.Albums
 
             var pagedEntities = await albumsQuery
                 .OrderByDescending(album => album.CreatedAt)
-                .Select(album => new { Album = album, TrackCount = album.AlbumTracks.Count })
+                .Select(album => new
+                {
+                    Album = album,
+                    TrackCount = album.AlbumTracks.Count,
+                    CoverTrackIds = album.AlbumTracks
+                        .OrderBy(albumTrack => albumTrack.TrackNumber)
+                        .Take(AlbumApplicationResponse.CoverTrackCount)
+                        .Select(albumTrack => albumTrack.TrackId)
+                        .ToList()
+                })
                 .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
 
             var pagedAlbums = new StaticPagedList<AlbumApplicationResponse>(
-                pagedEntities.Select(entry => AlbumApplicationResponse.FromEntity(entry.Album, entry.TrackCount)),
+                pagedEntities.Select(entry => AlbumApplicationResponse.FromEntity(entry.Album, entry.TrackCount, entry.CoverTrackIds)),
                 pagedEntities.PageNumber, pagedEntities.PageSize, pagedEntities.TotalItemCount);
 
             return PaginatedResponse<AlbumApplicationResponse>.FromPagedList(pagedAlbums);

backend/Musify.Application/Albums/GetAlbumsByUserId.cs

@@ -31,11 +31,20 @@ namespace Musify.Application.Albums
 
             var pagedEntities = await albumsQuery
                 .OrderByDescending(album => album.CreatedAt)
-                .Select(album => new { Album = album, TrackCount = album.AlbumTracks.Count })
+                .Select(album => new
+                {
+                    Album = album,
+                    TrackCount = album.AlbumTracks.Count,
+                    CoverTrackIds = album.AlbumTracks
+                        .OrderBy(albumTrack => albumTrack.TrackNumber)
+                        .Take(AlbumApplicationResponse.CoverTrackCount)
+                        .Select(albumTrack => albumTrack.TrackId)
+                        .ToList()
+                })
                 .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
 
             var pagedAlbums = new StaticPagedList<AlbumApplicationResponse>(
-                pagedEntities.Select(entry => AlbumApplicationResponse.FromEntity(entry.Album, entry.TrackCount)),
+                pagedEntities.Select(entry => AlbumApplicationResponse.FromEntity(entry.Album, entry.TrackCount, entry.CoverTrackIds)),
                 pagedEntities.PageNumber, pagedEntities.PageSize, pagedEntities.TotalItemCount);
 
             return PaginatedResponse<AlbumApplicationResponse>.FromPagedList(pagedAlbums);

backend/Musify.Application/Albums/Responses/AlbumApplicationResponse.cs

@@ -13,9 +13,15 @@ namespace Musify.Application.Albums.Responses
         string? MediumImageKeyName,
         string? LargeImageKeyName,
         DateTime CreatedAt,
-        DateTime UpdatedAt)
+        DateTime UpdatedAt,
+        IReadOnlyList<Guid> CoverTrackIds)
     {
-        public static AlbumApplicationResponse FromEntity(UserAlbum album, int trackCount)
+        public const int CoverTrackCount = 4;
+
+        public static AlbumApplicationResponse FromEntity(
+            UserAlbum album,
+            int trackCount,
+            IReadOnlyList<Guid>? coverTrackIds = null)
         {
             return new AlbumApplicationResponse(
                 album.Id,
@@ -28,7 +34,8 @@ namespace Musify.Application.Albums.Responses
                 album.Pictures?.MediumName,
                 album.Pictures?.LargeName,
                 album.CreatedAt,
-                album.UpdatedAt);
+                album.UpdatedAt,
+                coverTrackIds ?? []);
         }
     }
 }

backend/Musify.Application/Albums/SaveYouTubeAlbum.cs

@@ -89,14 +89,21 @@ namespace Musify.Application.Albums
                 return Error.Failure(description: $"Failed to save album {request.AlbumId}");
             }
 
-            var trackCount = await database.AlbumHasTracks
+            var albumTracks = database.AlbumHasTracks
                 .AsNoTracking()
-                .CountAsync(albumTrack => albumTrack.AlbumId == album.Id, cancellationToken);
+                .Where(albumTrack => albumTrack.AlbumId == album.Id);
+
+            var trackCount = await albumTracks.CountAsync(cancellationToken);
+            var coverTrackIds = await albumTracks
+                .OrderBy(albumTrack => albumTrack.TrackNumber)
+                .Take(AlbumApplicationResponse.CoverTrackCount)
+                .Select(albumTrack => albumTrack.TrackId)
+                .ToListAsync(cancellationToken);
 
             logger.LogInformation("Saved YouTube album {AlbumId} as {AlbumGuid} with {TrackCount} tracks",
                 request.AlbumId, album.Id, trackCount);
 
-            return AlbumApplicationResponse.FromEntity(album, trackCount);
+            return AlbumApplicationResponse.FromEntity(album, trackCount, coverTrackIds);
         }
 
         private static string Truncate(string value, int maxLength) =>

backend/Musify.Application/Albums/UpdateAlbum.cs

@@ -53,11 +53,18 @@ namespace Musify.Application.Albums
                 return Error.Failure(description: $"Failed to update album {request.AlbumId}");
             }
 
-            var trackCount = await database.AlbumHasTracks
+            var albumTracks = database.AlbumHasTracks
                 .AsNoTracking()
-                .CountAsync(albumTrack => albumTrack.AlbumId == album.Id, cancellationToken);
+                .Where(albumTrack => albumTrack.AlbumId == album.Id);
 
-            return AlbumApplicationResponse.FromEntity(album, trackCount);
+            var trackCount = await albumTracks.CountAsync(cancellationToken);
+            var coverTrackIds = await albumTracks
+                .OrderBy(albumTrack => albumTrack.TrackNumber)
+                .Take(AlbumApplicationResponse.CoverTrackCount)
+                .Select(albumTrack => albumTrack.TrackId)
+                .ToListAsync(cancellationToken);
+
+            return AlbumApplicationResponse.FromEntity(album, trackCount, coverTrackIds);
         }
     }
 }