feat(backend): add the album use cases

Create, update, delete and list albums, plus adding and removing their tracks, mirroring the playlist handlers. Only tracks the user uploaded can go into an album, and removing one renumbers the rest so the tracklist stays 1..n.
2026-07-20 20:10:45 +02:00
parent 67805062ca
commit 69468c9dbd
10 changed files with 518 additions and 0 deletions
@@ -0,0 +1,51 @@
+using ErrorOr;
+using Mediator;
+using Microsoft.EntityFrameworkCore;
+using Musify.Application.Contracts;
+using Musify.Application.Shared;
+using Musify.Application.Tracks.Responses;
+using Musify.Domain.Entities;
+using X.PagedList;
+using X.PagedList.EF;
+
+namespace Musify.Application.Albums
+{
+    public record GetAlbumTracksQuery(
+        Guid AlbumId,
+        int PageNumber,
+        int PageSize)
+        : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse>>>;
+
+    public class GetAlbumTracksQueryHandler(IDatabase database)
+        : IQueryHandler<GetAlbumTracksQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>>>
+    {
+        public async ValueTask<ErrorOr<PaginatedResponse<TrackApplicationResponse>>> Handle(GetAlbumTracksQuery request, CancellationToken cancellationToken)
+        {
+            var albumExists = await database.Albums
+                .AsNoTracking()
+                .AnyAsync(album => album.Id == request.AlbumId, cancellationToken);
+            if (!albumExists)
+                return Error.NotFound();
+
+            var tracksQuery = database.AlbumHasTracks
+                .AsNoTracking()
+                .Include(albumTrack => ((ExternalTrack)albumTrack.Track).TrackArtists)
+                    .ThenInclude(trackArtist => trackArtist.Artist)
+                .Include(albumTrack => ((LocalTrack)albumTrack.Track).Owner)
+                .Where(albumTrack => albumTrack.AlbumId == request.AlbumId);
+
+            var totalCount = await tracksQuery.CountAsync(cancellationToken);
+
+            var pagedEntities = await tracksQuery
+                .OrderBy(albumTrack => albumTrack.TrackNumber)
+                .Select(albumTrack => new { albumTrack.Track, ListensCount = albumTrack.Track.ListeningHistories.Count })
+                .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
+
+            var pagedTracks = new StaticPagedList<TrackApplicationResponse>(
+                pagedEntities.Select(entry => TrackApplicationResponse.FromEntity(entry.Track, entry.ListensCount)),
+                pagedEntities.PageNumber, pagedEntities.PageSize, pagedEntities.TotalItemCount);
+
+            return PaginatedResponse<TrackApplicationResponse>.FromPagedList(pagedTracks);
+        }
+    }
+}