Checkpoint web-player design-system refactor and backend track genre tagging

Advances the ongoing token/componentization cleanup (anchored player dock,
border-based panels instead of floating shadows, corrected light-mode
accent/gradient tokens) alongside in-progress backend support for track
genre tags.

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

@@ -29,6 +29,7 @@ namespace Musify.Application.Albums
             var tracksQuery = database.AlbumHasTracks
                 .AsNoTracking()
                 .Include(albumTrack => albumTrack.Track.Owner)
+                .Include(albumTrack => albumTrack.Track.Tags)
                 .Where(albumTrack => albumTrack.AlbumId == request.AlbumId);
 
             var totalCount = await tracksQuery.CountAsync(cancellationToken);

backend/Core/Musify.Application/Contracts/IDatabase.cs

@@ -31,6 +31,8 @@ namespace Musify.Application.Contracts
 
         DbSet<TrackLike> TrackLikes { get; }
 
+        DbSet<TrackTag> TrackTags { get; }
+
         DbSet<UserFollow> UserFollows { get; }
 
         Task<IDatabaseTransaction> BeginTransactionAsync(System.Data.IsolationLevel isolationLevel, CancellationToken cancellationToken);

backend/Core/Musify.Application/Likes/GetLikedTracks.cs

@@ -23,6 +23,7 @@ namespace Musify.Application.Likes
             var likesQuery = database.TrackLikes
                 .AsNoTracking()
                 .Include(like => like.Track.Owner)
+                .Include(like => like.Track.Tags)
                 .Where(like => like.UserId == request.UserId);
 
             var totalCount = await likesQuery.CountAsync(cancellationToken);

backend/Core/Musify.Application/Mixes/MixItemMapper.cs

@@ -21,14 +21,20 @@ namespace Musify.Application.Mixes
                 .AsNoTracking()
                 .Include(track => track.Owner)
                 .Where(track => trackIds.Contains(track.Id))
-                .ToDictionaryAsync(track => track.Id, cancellationToken);
+                .Select(track => new { Track = track, ListensCount = track.ListeningHistories.Count })
+                .ToDictionaryAsync(x => x.Track.Id, cancellationToken);
 
             return orderedItems
                 .Where(item => tracksById.ContainsKey(item.TrackId))
                 .Select(item =>
                 {
-                    var track = tracksById[item.TrackId];
-                    return new MixItemApplicationResponse(item.TrackId, track.Title, track.Owner.Name, track.DurationSeconds);
+                    var entry = tracksById[item.TrackId];
+                    return new MixItemApplicationResponse(
+                        item.TrackId,
+                        entry.Track.Title,
+                        entry.Track.Owner.Name,
+                        entry.Track.DurationSeconds,
+                        entry.ListensCount);
                 })
                 .ToList();
         }

backend/Core/Musify.Application/Mixes/Responses/MixItemApplicationResponse.cs

@@ -4,5 +4,6 @@ namespace Musify.Application.Mixes.Responses
         Guid TrackId,
         string Title,
         string? Artist,
-        double DurationSeconds);
+        double DurationSeconds,
+        int ListensCount);
 }

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

@@ -29,6 +29,7 @@ namespace Musify.Application.PlayLists
             var tracksQuery = database.PlayListHasTracks
                 .AsNoTracking()
                 .Include(plt => plt.Track.Owner)
+                .Include(plt => plt.Track.Tags)
                 .Where(plt => plt.PlayListId == request.PlayListId);
 
             var totalCount = await tracksQuery.CountAsync(cancellationToken);

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

@@ -17,7 +17,8 @@ namespace Musify.Application.Tracks
         long UserId,
         string Title,
         Guid PictureIntentId,
-        Guid AudioIntentId)
+        Guid AudioIntentId,
+        IReadOnlyCollection<Genre> Tags)
         : ICommand<ErrorOr<TrackApplicationResponse>>;
 
     public class CreateTrackCommandHandler(
@@ -40,6 +41,23 @@ namespace Musify.Application.Tracks
                 return Error.NotFound(description: $"User {request.UserId} not found");
             }
 
+            var distinctTags = request.Tags.Distinct().ToList();
+            if (distinctTags.Count == 0)
+            {
+                logger.LogWarning("Track {Title} was submitted without any tags", request.Title);
+                return Error.Validation(description: "At least one tag is required.");
+            }
+
+            var tagConflicts = GenreCompatibility.FindConflicts(distinctTags);
+            if (tagConflicts.Count > 0)
+            {
+                var conflict = tagConflicts.First();
+                logger.LogWarning(
+                    "Track {Title} was submitted with incompatible tags {First} and {Second}",
+                    request.Title, conflict.First, conflict.Second);
+                return Error.Validation(description: $"Tags '{conflict.First}' and '{conflict.Second}' are not compatible.");
+            }
+
             var pictureValidation = await uploadIntentValidator.ValidateAndLoadAsync(
                 uploadIntentConfiguration,
                 request.PictureIntentId, request.UserId, cancellationToken);
@@ -80,6 +98,10 @@ namespace Musify.Application.Tracks
                 }
             };
 
+            trackEntity.Tags = distinctTags
+                .Select(tag => new TrackTag { TrackId = trackEntity.Id, Tag = tag })
+                .ToList();
+
             await database.Tracks.AddAsync(trackEntity, cancellationToken);
 
             await database.UserHasTracks.AddAsync(new UserHasTrack

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

@@ -25,6 +25,7 @@ namespace Musify.Application.Tracks
 
             var tracksById = await database.Tracks
                 .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 } )
                 .ToDictionaryAsync(t => t.Id, cancellationToken);

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

@@ -16,6 +16,7 @@ namespace Musify.Application.Tracks
         {
             var entity = await database.Tracks.AsNoTracking()
                 .Include(t => t.Owner)
+                .Include(t => t.Tags)
                 .Where(t => t.Id == request.TrackId)
                 .Select(t => new { Track = t, ListensCount = t.ListeningHistories.Count })
                 .SingleOrDefaultAsync(cancellationToken);

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

@@ -19,6 +19,7 @@ namespace Musify.Application.Tracks
             var tracksQuery = database.UserHasTracks
                 .AsNoTracking()
                 .Include(ut => ut.Track.Owner)
+                .Include(ut => ut.Track.Tags)
                 .AsQueryable();
 
             if (!string.IsNullOrEmpty(request.Name))

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

@@ -27,6 +27,7 @@ namespace Musify.Application.Tracks
             var tracksQuery = database.UserHasTracks
                 .AsNoTracking()
                 .Include(ut => ut.Track.Owner)
+                .Include(ut => ut.Track.Tags)
                 .Where(p => p.UserId == request.UserId);
 
             if (!string.IsNullOrEmpty(request.Name))

backend/Core/Musify.Application/Tracks/Responses/TrackApplicationResponse.cs

@@ -14,7 +14,8 @@ namespace Musify.Application.Tracks.Responses
         int ListensCount,
         DateTime CreatedAt,
         DateTime UpdatedAt,
-        [property: JsonConverter(typeof(LongAsStringConverter))] long OwnerUserId)
+        [property: JsonConverter(typeof(LongAsStringConverter))] long OwnerUserId,
+        IReadOnlyCollection<Genre> Tags)
     {
         public static TrackApplicationResponse FromEntity(Track track, int listensCount) =>
             new(
@@ -26,6 +27,7 @@ namespace Musify.Application.Tracks.Responses
                 listensCount,
                 track.CreatedAt,
                 track.UpdatedAt,
-                track.OwnerUserId);
+                track.OwnerUserId,
+                track.Tags.Select(tag => tag.Tag).ToList());
     }
 }