Clean up Application layer commands/queries readability and correctness

Add missing AsNoTracking() on read-only queries, drop redundant
Update() calls on already-tracked entities, and fix inconsistent
formatting (stray spaces in generics, ternaries, and lambdas) across
the Albums/Tracks/PlayLists/Users command and query handlers.

backend/Core/Musify.Application/Albums/GetRecentlyListenedAlbums.cs

@@ -7,7 +7,7 @@ using Musify.Application.Contracts;
 namespace Musify.Application.Albums
 {
     public record GetRecentlyListenedAlbumsQuery(long UserId, int Limit)
-        : IQuery<ErrorOr<IReadOnlyList<AlbumApplicationResponse> >>;
+        : IQuery<ErrorOr<IReadOnlyList<AlbumApplicationResponse>>>;
 
     public class GetRecentlyListenedAlbumsQueryHandler(IDatabase database)
         : IQueryHandler<GetRecentlyListenedAlbumsQuery, ErrorOr<IReadOnlyList<AlbumApplicationResponse>>>
@@ -24,9 +24,9 @@ namespace Musify.Application.Albums
                     listenedTrackIds,
                     albumTrack => albumTrack.TrackId,
                     history => history.TrackId,
-                    (albumTrack, history) => new { albumTrack.AlbumId, history.ListenedAt } )
+                    (albumTrack, history) => new { albumTrack.AlbumId, history.ListenedAt })
                 .GroupBy(entry => entry.AlbumId)
-                .Select(group => new { AlbumId = group.Key, LastListenedAt = group.Max(entry => entry.ListenedAt) } )
+                .Select(group => new { AlbumId = group.Key, LastListenedAt = group.Max(entry => entry.ListenedAt) })
                 .OrderByDescending(entry => entry.LastListenedAt)
                 .Take(request.Limit)
                 .ToListAsync(cancellationToken);
@@ -48,7 +48,7 @@ namespace Musify.Application.Albums
                         .Take(AlbumApplicationResponse.CoverTrackCount)
                         .Select(albumTrack => albumTrack.TrackId)
                         .ToList()
-                } )
+                })
                 .ToDictionaryAsync(entry => entry.Album.Id, cancellationToken);
 
             return ranked

backend/Core/Musify.Application/Albums/RequestAlbumPictureUpload.cs

@@ -42,7 +42,7 @@ namespace Musify.Application.Albums
             var effectiveSizeBytes = request.ExpectedSizeBytes
                 ?? uploadIntentConfiguration.DefaultExpectedPictureSizeBytes;
 
-            var objectName = $"{Guid.NewGuid() }.{request.FileType.TrimStart('.').ToLowerInvariant() }";
+            var objectName = $"{Guid.NewGuid()}.{request.FileType.TrimStart('.').ToLowerInvariant()}";
 
             var tempKey = albumConfiguration.Routes.BuildTempPicturePath(
                 uploadIntentConfiguration.TemporalRootPrefix, request.UserId, objectName);
@@ -84,7 +84,7 @@ namespace Musify.Application.Albums
                 await database.SaveChangesAsync(cancellationToken);
                 await transaction.CommitAsync(cancellationToken);
 
-                logger.LogInformation("Issued upload intent {IntentId} for user {UserId} (AlbumPicture, temp key: {Key} )", intent.Id, request.UserId, tempKey);
+                logger.LogInformation("Issued upload intent {IntentId} for user {UserId} (AlbumPicture, temp key: {Key})", intent.Id, request.UserId, tempKey);
 
                 return new AlbumPictureUploadResponse(
                     intent.Id,

backend/Core/Musify.Application/Albums/UpdateAlbum.cs

@@ -77,8 +77,6 @@ namespace Musify.Application.Albums
                 finalPictureKey = albumConfiguration.Routes.BuildOriginalPicturePath(request.UserId, pictureIntent.ObjectName);
             }
 
-            database.Albums.Update(album);
-
             if (pictureIntent != null && finalPictureKey != null)
             {
                 var publishResult = await PublishUpdateAlbumPictureSourceEventAsync(

backend/Core/Musify.Application/PlayLists/CreatePlayList.cs

@@ -55,7 +55,7 @@ namespace Musify.Application.PlayLists
                 UserId = request.UserId,
                 Name = request.Name,
                 NormalizedName = request.Name.Trim().ToUpperInvariant(),
-                Description = string.IsNullOrWhiteSpace(request.Description)? null: request.Description.Trim(),
+                Description = string.IsNullOrWhiteSpace(request.Description) ? null : request.Description.Trim(),
                 Pictures = resolvedPictures.Pictures,
                 Visibility = request.Visibility
             };
@@ -106,7 +106,7 @@ namespace Musify.Application.PlayLists
             }, validation.Value);
         }
 
-        async Task<ErrorOr<Success>> PublishCreatePlayListEventAsync(
+        private async Task<ErrorOr<Success>> PublishCreatePlayListEventAsync(
             Guid playListId,
             UploadIntent pictureIntent,
             string finalPictureKey,

backend/Core/Musify.Application/PlayLists/GetPlayListTracks.cs

@@ -16,9 +16,9 @@ namespace Musify.Application.PlayLists
         : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse>>>;
 
     public class GetPlayListTracksQueryHandler(IDatabase database)
-        : IQueryHandler<GetPlayListTracksQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>> >
+        : IQueryHandler<GetPlayListTracksQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>>>
     {
-        public async ValueTask<ErrorOr<PaginatedResponse<TrackApplicationResponse> >> Handle(GetPlayListTracksQuery request, CancellationToken cancellationToken)
+        public async ValueTask<ErrorOr<PaginatedResponse<TrackApplicationResponse>>> Handle(GetPlayListTracksQuery request, CancellationToken cancellationToken)
         {
             var playListExists = await database.PlayLists
                 .AsNoTracking()

backend/Core/Musify.Application/PlayLists/GetPlayLists.cs

@@ -10,12 +10,12 @@ using Musify.Application.Contracts;
 namespace Musify.Application.PlayLists
 {
     public record GetPlayListsQuery(int PageNumber, int PageSize)
-        : IQuery<ErrorOr<PaginatedResponse<PlayListApplicationResponse>> >;
+        : IQuery<ErrorOr<PaginatedResponse<PlayListApplicationResponse>>>;
 
     public class GetPlayListsQueryHandler(IDatabase database)
-        : IQueryHandler<GetPlayListsQuery, ErrorOr<PaginatedResponse<PlayListApplicationResponse> >>
+        : IQueryHandler<GetPlayListsQuery, ErrorOr<PaginatedResponse<PlayListApplicationResponse>>>
     {
-        public async ValueTask<ErrorOr<PaginatedResponse<PlayListApplicationResponse> >> Handle(GetPlayListsQuery request, CancellationToken cancellationToken)
+        public async ValueTask<ErrorOr<PaginatedResponse<PlayListApplicationResponse>>> Handle(GetPlayListsQuery request, CancellationToken cancellationToken)
         {
             var totalCount = await database.PlayLists.CountAsync(cancellationToken);
 

backend/Core/Musify.Application/PlayLists/GetPlayListsByUserId.cs

@@ -16,12 +16,12 @@ namespace Musify.Application.PlayLists
         int PageNumber,
         int PageSize,
         bool OnlyPublic = false)
-        : IQuery<ErrorOr<PaginatedResponse<PlayListApplicationResponse>> >;
+        : IQuery<ErrorOr<PaginatedResponse<PlayListApplicationResponse>>>;
 
     public class GetPlayListsByUserIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetPlayListsByUserIdQuery, ErrorOr<PaginatedResponse<PlayListApplicationResponse> > >
+        : IQueryHandler<GetPlayListsByUserIdQuery, ErrorOr<PaginatedResponse<PlayListApplicationResponse>>>
     {
-        public async ValueTask<ErrorOr<PaginatedResponse<PlayListApplicationResponse> >> Handle(GetPlayListsByUserIdQuery request, CancellationToken cancellationToken)
+        public async ValueTask<ErrorOr<PaginatedResponse<PlayListApplicationResponse>>> Handle(GetPlayListsByUserIdQuery request, CancellationToken cancellationToken)
         {
             var playListsQuery = database.PlayLists
                 .AsNoTracking()
@@ -51,7 +51,7 @@ namespace Musify.Application.PlayLists
                         .Take(PlayListApplicationResponse.CoverTrackCount)
                         .Select(plt => plt.TrackId)
                         .ToList()
-                } )
+                })
                 .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
 
             var pagedPlayLists = new StaticPagedList<PlayListApplicationResponse>(

backend/Core/Musify.Application/PlayLists/RequestPlayListPictureUpload.cs

@@ -42,7 +42,7 @@ namespace Musify.Application.PlayLists
             var effectiveSizeBytes = request.ExpectedSizeBytes
                 ?? uploadIntentConfiguration.DefaultExpectedPictureSizeBytes;
 
-            var objectName = $"{Guid.NewGuid() }.{request.FileType.TrimStart('.').ToLowerInvariant() }";
+            var objectName = $"{Guid.NewGuid()}.{request.FileType.TrimStart('.').ToLowerInvariant()}";
 
             var tempKey = playListConfiguration.Routes.BuildTempPicturePath(
                 uploadIntentConfiguration.TemporalRootPrefix, request.UserId, objectName);
@@ -84,7 +84,7 @@ namespace Musify.Application.PlayLists
                 await database.SaveChangesAsync(cancellationToken);
                 await transaction.CommitAsync(cancellationToken);
 
-                logger.LogInformation("Issued upload intent {IntentId} for user {UserId} (PlayListPicture, temp key: {Key} )", intent.Id, request.UserId, tempKey);
+                logger.LogInformation("Issued upload intent {IntentId} for user {UserId} (PlayListPicture, temp key: {Key})", intent.Id, request.UserId, tempKey);
 
                 return new PlayListPictureUploadResponse(
                     intent.Id,

backend/Core/Musify.Application/PlayLists/UpdatePlayList.cs

@@ -85,9 +85,7 @@ namespace Musify.Application.PlayLists
                 finalPictureKey = playListConfiguration.Routes.BuildOriginalPicturePath(request.UserId, pictureIntent.ObjectName);
             }
 
-            database.PlayLists.Update(playListEntity);
+            if (pictureIntent != null && finalPictureKey != null)
-
-            if (pictureIntent != null&& finalPictureKey != null)
             {
                 var publishResult = await PublishUpdatePlayListPictureSourceEventAsync(
                     playListEntity.Id, pictureIntent, finalPictureKey, cancellationToken);
@@ -117,7 +115,7 @@ namespace Musify.Application.PlayLists
             return PlayListApplicationResponse.FromEntity(playListEntity, coverTrackIds);
         }
 
-        async Task<ErrorOr<Success>> PublishUpdatePlayListPictureSourceEventAsync(
+        private async Task<ErrorOr<Success>> PublishUpdatePlayListPictureSourceEventAsync(
             Guid playListId,
             UploadIntent pictureIntent,
             string finalPictureKey,

backend/Core/Musify.Application/Tracks/GetLastTrackListenedByUserId.cs

@@ -14,6 +14,7 @@ namespace Musify.Application.Tracks
         public async ValueTask<ErrorOr<TrackApplicationResponse>> Handle(GetLastTrackListenedByUserIdQuery query, CancellationToken cancellationToken)
         {
             var track = await database.ListeningHistories
+                .AsNoTracking()
                 .Include(t => t.Track.Owner)
                 .Include(t => t.Track.Tags)
                 .Where(t => t.UserId == query.UserId)

backend/Core/Musify.Application/Tracks/GetListeningHistory.cs

@@ -16,6 +16,7 @@ namespace Musify.Application.Tracks
         public async ValueTask<IEnumerable<TrackApplicationResponse>> Handle(GetListeningHistoryQuery query, CancellationToken cancellationToken)
         {
             var recentTrackIds = await database.ListeningHistories
+                .AsNoTracking()
                 .Where(l => l.UserId == query.UserId)
                 .GroupBy(l => l.TrackId)
                 .OrderByDescending(g => g.Max(l => l.ListenedAt))
@@ -24,14 +25,15 @@ namespace Musify.Application.Tracks
                 .ToListAsync(cancellationToken);
 
             var tracksById = await database.Tracks
+                .AsNoTracking()
                 .Include(t => t.Owner)
                 .Include(t => t.Tags)
                 .Where(t => recentTrackIds.Contains(t.Id))
-                .Select(t => new { t.Id, Track = t, ListensCount = t.ListeningHistories.Count } )
+                .Select(t => new { t.Id, Track = t, ListensCount = t.ListeningHistories.Count })
                 .ToDictionaryAsync(t => t.Id, cancellationToken);
 
             return recentTrackIds
-                .Select(id => tracksById[id] )
+                .Select(id => tracksById[id])
                 .Select(t => TrackApplicationResponse.FromEntity(t.Track, t.ListensCount));
         }
     }

backend/Core/Musify.Application/Tracks/GetTrackById.cs

@@ -10,7 +10,7 @@ namespace Musify.Application.Tracks
         : IQuery<ErrorOr<TrackApplicationResponse>>;
 
     public class GetTrackByIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetTrackByIdQuery, ErrorOr<TrackApplicationResponse> >
+        : IQueryHandler<GetTrackByIdQuery, ErrorOr<TrackApplicationResponse>>
     {
         public async ValueTask<ErrorOr<TrackApplicationResponse>> Handle(GetTrackByIdQuery request, CancellationToken cancellationToken)
         {

backend/Core/Musify.Application/Tracks/GetTrackCover.cs

@@ -48,6 +48,6 @@ namespace Musify.Application.Tracks
         }
 
         private static string? BuildKey(Func<string, string> builder, string? name)
-            => string.IsNullOrEmpty(name)? null: builder(name);
+            => string.IsNullOrEmpty(name) ? null : builder(name);
     }
 }

backend/Core/Musify.Application/Tracks/GetTracks.cs

@@ -33,7 +33,7 @@ namespace Musify.Application.Tracks
             var pagedEntities = await tracksQuery
                 .OrderByDescending(t => t.Track.CreatedAt)
                 .ThenBy(t => t.Id)
-                .Select(t => new { t.Track, ListensCount = t.Track.ListeningHistories.Count } )
+                .Select(t => new { t.Track, ListensCount = t.Track.ListeningHistories.Count })
                 .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
 
             var items = pagedEntities

backend/Core/Musify.Application/Tracks/GetTracksByUserId.cs

@@ -14,12 +14,12 @@ namespace Musify.Application.Tracks
         string? Name,
         int PageNumber,
         int PageSize)
-        : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse> > >;
+        : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse>>>;
 
     public class GetTracksByUserIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetTracksByUserIdQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>> >
+        : IQueryHandler<GetTracksByUserIdQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>>>
     {
-        public async ValueTask<ErrorOr<PaginatedResponse<TrackApplicationResponse> >> Handle(GetTracksByUserIdQuery request, CancellationToken cancellationToken)
+        public async ValueTask<ErrorOr<PaginatedResponse<TrackApplicationResponse>>> Handle(GetTracksByUserIdQuery request, CancellationToken cancellationToken)
         {
             var pageNumber = request.PageNumber < 1 ? 1 : request.PageNumber;
             var pageSize = request.PageSize < 1 ? 10 : request.PageSize;

backend/Core/Musify.Application/Users/CreateUser.cs

@@ -28,7 +28,7 @@ namespace Musify.Application.Users
     }
 
     public class CreateUserCommandHandler(IDatabase database, ILogger<CreateUserCommandHandler> logger)
-        : ICommandHandler<CreateUserCommand, ErrorOr<UserApplicationResponse> >
+        : ICommandHandler<CreateUserCommand, ErrorOr<UserApplicationResponse>>
     {
         public async ValueTask<ErrorOr<UserApplicationResponse>> Handle(CreateUserCommand request, CancellationToken cancellationToken)
         {

backend/Core/Musify.Application/Users/GetListeningStats.cs

@@ -16,6 +16,7 @@ namespace Musify.Application.Users
             var weekAgo = DateTime.UtcNow.AddDays(-7);
 
             var thisWeekHistory = database.ListeningHistories
+                .AsNoTracking()
                 .Where(l => l.UserId == request.UserId && l.ListenedAt >= weekAgo);
 
             var tracksThisWeek = await thisWeekHistory
@@ -24,10 +25,11 @@ namespace Musify.Application.Users
                 .CountAsync(cancellationToken);
 
             var secondsThisWeek = await thisWeekHistory
-                .Join(database.Tracks, l => l.TrackId, t => t.Id, (l, t) => t.DurationSeconds)
+                .Join(database.Tracks.AsNoTracking(), l => l.TrackId, t => t.Id, (l, t) => t.DurationSeconds)
                 .SumAsync(cancellationToken);
 
             var listenedDates = await database.ListeningHistories
+                .AsNoTracking()
                 .Where(l => l.UserId == request.UserId)
                 .Select(l => l.ListenedAt.Date)
                 .Distinct()

backend/Core/Musify.Application/Users/GetUserById.cs

@@ -7,10 +7,10 @@ using Musify.Application.Users.Responses;
 namespace Musify.Application.Users
 {
     public record GetUserByIdQuery(long Id)
-        : IQuery<ErrorOr<UserApplicationResponse> >;
+        : IQuery<ErrorOr<UserApplicationResponse>>;
 
     public class GetUserByIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetUserByIdQuery, ErrorOr<UserApplicationResponse> >
+        : IQueryHandler<GetUserByIdQuery, ErrorOr<UserApplicationResponse>>
     {
         public async ValueTask<ErrorOr<UserApplicationResponse>> Handle(GetUserByIdQuery request, CancellationToken cancellationToken)
         {

backend/Core/Musify.Application/Users/GetUsers.cs

@@ -9,29 +9,29 @@ using Musify.Application.Contracts;
 namespace Musify.Application.Users
 {
     public record GetUsersQuery(int PageNumber, int PageSize, string? UsernameSearch)
-        : IQuery<ErrorOr<PaginatedResponse<UserApplicationResponse> >>;
+        : IQuery<ErrorOr<PaginatedResponse<UserApplicationResponse>>>;
 
     public class GetUsersQueryHandler(IDatabase database)
-        : IQueryHandler<GetUsersQuery, ErrorOr<PaginatedResponse<UserApplicationResponse> > >
+        : IQueryHandler<GetUsersQuery, ErrorOr<PaginatedResponse<UserApplicationResponse>>>
     {
-        public async ValueTask<ErrorOr<PaginatedResponse<UserApplicationResponse> >> Handle(GetUsersQuery request, CancellationToken cancellationToken)
+        public async ValueTask<ErrorOr<PaginatedResponse<UserApplicationResponse>>> Handle(GetUsersQuery request, CancellationToken cancellationToken)
         {
-            var user = database.Users
+            var usersQuery = database.Users
                 .AsNoTracking()
                 .AsQueryable();
 
             if (!string.IsNullOrEmpty(request.UsernameSearch))
             {
                 var normalizedUsername = request.UsernameSearch.Trim().ToUpperInvariant();
-                user = user.Where(u => u.NormalizedName.Contains(normalizedUsername));
+                usersQuery = usersQuery.Where(u => u.NormalizedName.Contains(normalizedUsername));
             }
 
-            var totalCount = await user.CountAsync(cancellationToken);
+            var totalCount = await usersQuery.CountAsync(cancellationToken);
-            var pagedUser = await user
+            var pagedUsers = await usersQuery
                 .Select(u => UserApplicationResponse.FromEntity(u))
                 .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
 
-            return PaginatedResponse<UserApplicationResponse>.FromPagedList(pagedUser);
+            return PaginatedResponse<UserApplicationResponse>.FromPagedList(pagedUsers);
         }
     }
 }