Simplify infrastructure services and move all recurring jobs to Hangfire

Reviewed-on: #22

.gitea/workflows/ci-cd.yml

@@ -86,11 +86,23 @@ jobs:
           git fetch origin master
           git reset --hard origin/master
 
-      - name: Migrate database, generate keys
+      - name: Generate stream-ticket keys
         run: |
           set -euo pipefail
           cd "$DEPLOY_PATH"
-          $COMPOSE up -d wait-for-postgres keys-init migrate
+          $COMPOSE run --rm --no-deps keys-init
+
+      # The migrations are baked into the migrator image, so it is rebuilt on
+      # every deploy (plain `up` would reuse the stale image and re-apply the
+      # old migrations). `run --rm` starts wait-for-postgres, blocks until the
+      # migration finishes and propagates its exit code, so a failed migration
+      # aborts the deploy before the new API is started against an old schema.
+      - name: Migrate database
+        run: |
+          set -euo pipefail
+          cd "$DEPLOY_PATH"
+          $COMPOSE build migrate
+          $COMPOSE run --rm migrate
 
       # Both jobs verify themselves through the public auth./s3. URLs, served
       # by the shared edge nginx (Infrastructure's edge/), and are idempotent.

backend/.editorconfig

@@ -0,0 +1,65 @@
+root = true
+
+[*]
+charset = utf-8
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+
+[*.{csproj,props,targets,slnx,xml}]
+indent_size = 2
+
+[*.json]
+indent_size = 4
+
+[**/Migrations/**.cs]
+generated_code = true
+
+[*.cs]
+indent_size = 4
+
+csharp_style_namespace_declarations = file_scoped:warning
+csharp_using_directive_placement = outside_namespace:warning
+dotnet_sort_system_directives_first = true
+dotnet_separate_import_directive_groups = false
+dotnet_diagnostic.IDE0005.severity = warning
+
+dotnet_style_require_accessibility_modifiers = always:warning
+csharp_style_var_for_built_in_types = true:suggestion
+csharp_style_var_when_type_is_apparent = true:suggestion
+csharp_style_var_elsewhere = true:suggestion
+csharp_prefer_braces = when_multiline:warning
+csharp_style_prefer_primary_constructors = true:suggestion
+csharp_style_expression_bodied_methods = when_on_single_line:suggestion
+dotnet_style_prefer_collection_expression = when_types_loosely_match:suggestion
+
+dotnet_naming_rule.private_fields.symbols = private_fields
+dotnet_naming_rule.private_fields.style = camel_case
+dotnet_naming_rule.private_fields.severity = warning
+dotnet_naming_symbols.private_fields.applicable_kinds = field
+dotnet_naming_symbols.private_fields.applicable_accessibilities = private
+dotnet_naming_symbols.private_fields.required_modifiers =
+dotnet_naming_style.camel_case.capitalization = camel_case
+
+dotnet_naming_rule.private_constants.symbols = private_constants
+dotnet_naming_rule.private_constants.style = pascal_case
+dotnet_naming_rule.private_constants.severity = warning
+dotnet_naming_symbols.private_constants.applicable_kinds = field
+dotnet_naming_symbols.private_constants.required_modifiers = const
+dotnet_naming_style.pascal_case.capitalization = pascal_case
+
+# Analyzer rules that would need behaviour or API changes; downgraded in P0, revisit in P15.
+dotnet_diagnostic.CA1848.severity = suggestion
+dotnet_diagnostic.CA1873.severity = suggestion
+dotnet_diagnostic.CA1305.severity = suggestion
+dotnet_diagnostic.CA1707.severity = suggestion
+dotnet_diagnostic.CA1859.severity = suggestion
+dotnet_diagnostic.CA1716.severity = suggestion
+dotnet_diagnostic.CA1000.severity = suggestion
+dotnet_diagnostic.CA1725.severity = suggestion
+dotnet_diagnostic.CA1816.severity = suggestion
+dotnet_diagnostic.CA1822.severity = suggestion
+dotnet_diagnostic.CA1852.severity = suggestion
+dotnet_diagnostic.CA1068.severity = suggestion
+dotnet_diagnostic.CA1711.severity = suggestion
+dotnet_diagnostic.CA1861.severity = suggestion

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

@@ -1,82 +0,0 @@
-using ErrorOr;
-using Mediator;
-using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.Logging;
-using Musify.Application.Contracts;
-using Musify.Domain.Entities;
-
-namespace Musify.Application.Albums
-{
-    public record AddTrackToAlbumCommand(long UserId, Guid AlbumId, Guid TrackId)
-        : ICommand<ErrorOr<Success>>;
-
-    public class AddTrackToAlbumCommandHandler(
-        IDatabase database,
-        ILogger<AddTrackToAlbumCommandHandler> logger)
-        : ICommandHandler<AddTrackToAlbumCommand, ErrorOr<Success>>
-    {
-        public async ValueTask<ErrorOr<Success>> Handle(AddTrackToAlbumCommand request, CancellationToken cancellationToken)
-        {
-            var album = await database.Albums
-                .AsNoTracking()
-                .SingleOrDefaultAsync(a => a.Id == request.AlbumId, cancellationToken);
-            if (album == null)
-            {
-                logger.LogInformation("Album {AlbumId} not found", request.AlbumId);
-                return Error.NotFound();
-            }
-
-            if (album.OwnerUserId != request.UserId)
-            {
-                logger.LogWarning("User {UserId} is not the owner of album {AlbumId}", request.UserId, request.AlbumId);
-                return Error.Unauthorized();
-            }
-
-            var track = await database.Tracks
-                .AsNoTracking()
-                .SingleOrDefaultAsync(t => t.Id == request.TrackId, cancellationToken);
-            if (track == null)
-            {
-                logger.LogInformation("Track {TrackId} not found", request.TrackId);
-                return Error.NotFound(description: $"Track {request.TrackId} not found");
-            }
-
-            if (track.OwnerUserId != request.UserId)
-            {
-                logger.LogWarning("User {UserId} does not own track {TrackId}", request.UserId, request.TrackId);
-                return Error.Unauthorized();
-            }
-
-            var alreadyAdded = await database.AlbumHasTracks
-                .AsNoTracking()
-                .AnyAsync(albumTrack => albumTrack.AlbumId == request.AlbumId && albumTrack.TrackId == request.TrackId, cancellationToken);
-            if (alreadyAdded)
-            {
-                logger.LogInformation("Track {TrackId} already in album {AlbumId}", request.TrackId, request.AlbumId);
-                return Error.Conflict(description: "Track is already in the album.");
-            }
-
-            var albumTracksQuery = database.AlbumHasTracks
-                .Where(albumTrack => albumTrack.AlbumId == request.AlbumId);
-
-            var hasTracks = await albumTracksQuery.AnyAsync(cancellationToken);
-            var nextTrackNumber = hasTracks
-                ? await albumTracksQuery.MaxAsync(albumTrack => albumTrack.TrackNumber, cancellationToken) + 1
-                : 1;
-
-            await database.AlbumHasTracks.AddAsync(new AlbumHasTrack
-            {
-                AlbumId = request.AlbumId,
-                TrackId = request.TrackId,
-                TrackNumber = nextTrackNumber
-            }, cancellationToken);
-
-            await database.SaveChangesAsync(cancellationToken);
-
-            logger.LogInformation("Added track {TrackId} to album {AlbumId} as number {TrackNumber}",
-                request.TrackId, request.AlbumId, nextTrackNumber);
-
-            return new Success();
-        }
-    }
-}

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

@@ -0,0 +1,77 @@
+using ErrorOr;
+using Mediator;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+using Musify.Application.Contracts;
+using Musify.Application.Shared;
+using Musify.Domain.Entities;
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.Albums;
+
+/// <summary>Appends your own tracks to an album in the given order, skipping the ones it already has.</summary>
+public record AddTracksToAlbumCommand(long UserId, Guid AlbumId, IReadOnlyList<Guid> TrackIds)
+    : ICommand<ErrorOr<Success>>;
+
+public class AddTracksToAlbumCommandHandler(
+    IDatabase database,
+    ILogger<AddTracksToAlbumCommandHandler> logger)
+    : ICommandHandler<AddTracksToAlbumCommand, ErrorOr<Success>>
+{
+    public async ValueTask<ErrorOr<Success>> Handle(AddTracksToAlbumCommand request, CancellationToken cancellationToken)
+    {
+        var album = await database.Albums.FindOwnedAsync(request.AlbumId, request.UserId, cancellationToken);
+        if (album.IsError)
+            return album.Errors;
+
+        var requestedIds = request.TrackIds.Distinct().ToList();
+
+        var tracks = await database.Tracks
+            .AsNoTracking()
+            .Where(track => requestedIds.Contains(track.Id) && track.LifeCycleStatus == LifeCycleStatus.Active)
+            .Select(track => new { track.Id, track.OwnerUserId })
+            .ToListAsync(cancellationToken);
+
+        var missing = requestedIds.FirstOrDefault(id => tracks.All(track => track.Id != id));
+        if (missing != Guid.Empty)
+            return AppErrors.NotFound("Track", missing);
+
+        var foreign = tracks.FirstOrDefault(track => track.OwnerUserId != request.UserId);
+        if (foreign != null)
+            return AppErrors.Forbidden("Track", foreign.Id);
+
+        var alreadyInAlbum = await database.AlbumHasTracks
+            .AsNoTracking()
+            .Where(link => link.AlbumId == request.AlbumId && requestedIds.Contains(link.TrackId))
+            .Select(link => link.TrackId)
+            .ToListAsync(cancellationToken);
+
+        var toAdd = requestedIds.Where(id => !alreadyInAlbum.Contains(id)).ToList();
+        if (toAdd.Count == 0)
+            return Result.Success;
+
+        // Album track numbers are user-visible, so they start at 1.
+        var nextTrackNumber = (await database.AlbumHasTracks
+            .Where(link => link.AlbumId == request.AlbumId)
+            .MaxAsync(link => (int?)link.TrackNumber, cancellationToken) ?? 0) + 1;
+
+        foreach (var trackId in toAdd)
+        {
+            await database.AlbumHasTracks.AddAsync(new AlbumHasTrack
+            {
+                AlbumId = request.AlbumId,
+                TrackId = trackId,
+                TrackNumber = nextTrackNumber++
+            }, cancellationToken);
+        }
+
+        var saved = await database.TrySaveChangesAsync(
+            AppErrors.Conflict("Album.ConcurrentChange", "The album changed while adding tracks. Try again."), cancellationToken);
+        if (saved.IsError)
+            return saved;
+
+        logger.LogInformation("Added {Count} tracks to album {AlbumId}", toAdd.Count, request.AlbumId);
+
+        return Result.Success;
+    }
+}

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

@@ -2,127 +2,71 @@ using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
-using Musify.Application.Configuration;
-using Musify.Application.Shared;
-using Musify.Application.Events;
 using Musify.Application.Albums.Responses;
+using Musify.Application.Configuration;
+using Musify.Application.Contracts;
+using Musify.Application.Events;
+using Musify.Application.Pictures;
 using Musify.Application.Services;
+using Musify.Application.Shared;
 using Musify.Domain.Entities;
 using Musify.Domain.ValueObjects;
-using Musify.Application.Contracts;
 
-namespace Musify.Application.Albums
+namespace Musify.Application.Albums;
+
+public record CreateAlbumCommand(
+    long UserId,
+    string Title,
+    string? Description,
+    int? ReleaseYear,
+    Guid PictureIntentId)
+    : ICommand<ErrorOr<AlbumApplicationResponse>>;
+
+public class CreateAlbumCommandHandler(
+    IEventBus eventBus,
+    IDatabase database,
+    UploadIntentValidator uploadIntentValidator,
+    ILogger<CreateAlbumCommandHandler> logger,
+    AlbumConfiguration albumConfiguration)
+    : ICommandHandler<CreateAlbumCommand, ErrorOr<AlbumApplicationResponse>>
 {
-    public record CreateAlbumCommand(
-        long UserId,
-        string Title,
-        string? Description,
-        int? ReleaseYear,
-        Guid PictureIntentId)
-        : ICommand<ErrorOr<AlbumApplicationResponse>>;
-
-    public class CreateAlbumCommandHandler(
-        IEventBus eventBus,
-        IDatabase database,
-        UploadIntentValidator uploadIntentValidator,
-        ILogger<CreateAlbumCommandHandler> logger,
-        ApplicationStorageConfiguration storageConfiguration,
-        AlbumConfiguration albumConfiguration,
-        UploadIntentConfiguration uploadIntentConfiguration)
-        : ICommandHandler<CreateAlbumCommand, ErrorOr<AlbumApplicationResponse>>
+    public async ValueTask<ErrorOr<AlbumApplicationResponse>> Handle(CreateAlbumCommand request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<AlbumApplicationResponse>> Handle(CreateAlbumCommand request, CancellationToken cancellationToken)
+        var userExists = await database.Users
+            .AsNoTracking()
+            .AnyAsync(user => user.Id == request.UserId, cancellationToken);
+        if (!userExists)
+            return AppErrors.NotFound("User", request.UserId);
+
+        var prepared = await PictureSourceChange.PrepareAsync(
+            uploadIntentValidator, request.PictureIntentId, request.UserId, UploadIntentPurpose.AlbumPicture, albumConfiguration, cancellationToken);
+        if (prepared.IsError)
+            return prepared.Errors;
+
+        var picture = prepared.Value;
+        var title = request.Title.Trim();
+
+        var album = new Album
         {
-            var userExists = await database.Users
-                .AsNoTracking()
-                .AnyAsync(user => user.Id == request.UserId, cancellationToken);
-            if (!userExists)
-            {
-                logger.LogWarning("User {UserId} not found", request.UserId);
-                return Error.NotFound(description: $"User {request.UserId} not found");
-            }
+            OwnerUserId = request.UserId,
+            Title = title,
+            NormalizedTitle = TextNormalizer.Normalize(title),
+            Description = request.Description,
+            ReleaseYear = request.ReleaseYear,
+            Pictures = picture.Pictures
+        };
 
-            var pictureIntent = await uploadIntentValidator.ValidateAndLoadAsync(
-                uploadIntentConfiguration, request.PictureIntentId, request.UserId, cancellationToken);
-            if (pictureIntent.IsError)
-                return pictureIntent.Errors;
+        await database.Albums.AddAsync(album, cancellationToken);
 
-            var intent = pictureIntent.Value;
-            var title = request.Title.Trim();
+        await eventBus.PublishAsync(
+            new CreateAlbumResourcesEvent(
+                album.Id, picture.Intent.Id, picture.Intent.Bucket, picture.Intent.Key, picture.FinalKey, picture.Sizes),
+            cancellationToken);
 
-            var album = new Album
-            {
-                OwnerUserId = request.UserId,
-                Title = title,
-                NormalizedTitle = title.ToUpperInvariant(),
-                Description = request.Description,
-                ReleaseYear = request.ReleaseYear,
-                Pictures = new AlbumPictures
-                {
-                    OriginalName = intent.ObjectName,
-                    SmallName = intent.ObjectName,
-                    MediumName = intent.ObjectName,
-                    LargeName = intent.ObjectName
-                }
-            };
+        await database.SaveChangesAsync(cancellationToken);
 
-            await database.Albums.AddAsync(album, cancellationToken);
+        logger.LogInformation("Created album {AlbumId} for user {UserId}", album.Id, request.UserId);
 
-            var finalPictureKey = albumConfiguration.Routes.BuildOriginalPicturePath(request.UserId, intent.ObjectName);
-            var publishResult = await PublishCreateAlbumEventAsync(album.Id, intent, finalPictureKey, cancellationToken);
-            if (publishResult.IsError)
-                return publishResult.Errors;
-
-            try
-            {
-                await database.SaveChangesAsync(cancellationToken);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to save album for user {UserId}", request.UserId);
-                return Error.Failure(description: $"Failed to create album for user {request.UserId}");
-            }
-
-            logger.LogInformation("Created album {AlbumId} for user {UserId}", album.Id, request.UserId);
-
-            return AlbumApplicationResponse.FromEntity(album, trackCount: 0);
-        }
-
-        private async Task<ErrorOr<Success>> PublishCreateAlbumEventAsync(
-            Guid albumId,
-            UploadIntent pictureIntent,
-            string finalPictureKey,
-            CancellationToken cancellationToken)
-        {
-            try
-            {
-                await eventBus.PublishAsync(
-                    new CreateAlbumResourcesEvent(
-                        albumId,
-                        pictureIntent.Id,
-                        storageConfiguration.Bucket,
-                        pictureIntent.Key,
-                        finalPictureKey,
-                        new ImageSize(
-                            albumConfiguration.Routes.SmallPicturesPath,
-                            albumConfiguration.PicturesSizes.SmallPictureWidth,
-                            albumConfiguration.PicturesSizes.SmallPictureHeight),
-                        new ImageSize(
-                            albumConfiguration.Routes.MediumPicturesPath,
-                            albumConfiguration.PicturesSizes.MediumPictureWidth,
-                            albumConfiguration.PicturesSizes.MediumPictureHeight),
-                        new ImageSize(
-                            albumConfiguration.Routes.LargePicturesPath,
-                            albumConfiguration.PicturesSizes.LargePictureWidth,
-                            albumConfiguration.PicturesSizes.LargePictureHeight)),
-                    cancellationToken);
-                return new Success();
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to publish create album event for album {AlbumId}", albumId);
-                return Error.Failure(description: $"Failed to publish create album event for album {albumId}");
-            }
-        }
+        return AlbumApplicationResponse.FromEntity(album, trackCount: 0);
     }
 }

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

@@ -1,50 +1,36 @@
 using ErrorOr;
 using Mediator;
-using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
 using Musify.Application.Contracts;
+using Musify.Application.Events;
+using Musify.Application.Shared;
+using Musify.Domain.ValueObjects;
 
-namespace Musify.Application.Albums
+namespace Musify.Application.Albums;
+
+public record DeleteAlbumCommand(long UserId, Guid AlbumId)
+    : ICommand<ErrorOr<Success>>;
+
+public class DeleteAlbumCommandHandler(
+    IDatabase database,
+    IEventBus eventBus,
+    ILogger<DeleteAlbumCommandHandler> logger)
+    : ICommandHandler<DeleteAlbumCommand, ErrorOr<Success>>
 {
-    public record DeleteAlbumCommand(long UserId, Guid AlbumId)
-        : ICommand<ErrorOr<Success>>;
-
-    public class DeleteAlbumCommandHandler(
-        IDatabase database,
-        ILogger<DeleteAlbumCommandHandler> logger)
-        : ICommandHandler<DeleteAlbumCommand, ErrorOr<Success>>
+    public async ValueTask<ErrorOr<Success>> Handle(DeleteAlbumCommand request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<Success>> Handle(DeleteAlbumCommand request, CancellationToken cancellationToken)
-        {
-            var album = await database.Albums
-                .SingleOrDefaultAsync(a => a.Id == request.AlbumId, cancellationToken);
-            if (album == null)
-            {
-                logger.LogDebug("Album {AlbumId} not found", request.AlbumId);
-                return Error.NotFound();
-            }
+        var found = await database.Albums.FindOwnedAsync(request.AlbumId, request.UserId, cancellationToken);
+        if (found.IsError)
+            return found.Errors;
 
-            if (album.OwnerUserId != request.UserId)
-            {
-                logger.LogWarning("Album {AlbumId} does not belong to user {UserId}", request.AlbumId, request.UserId);
-                return Error.Unauthorized();
-            }
+        var album = found.Value;
+        album.LifeCycleStatus = LifeCycleStatus.Removing;
 
-            database.Albums.Remove(album);
+        await eventBus.PublishAsync(new DeleteAlbumEvent(album.Id, request.UserId), cancellationToken);
+        await database.SaveChangesAsync(cancellationToken);
 
-            try
-            {
-                await database.SaveChangesAsync(cancellationToken);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to delete album {AlbumId}", request.AlbumId);
-                return Error.Failure(description: $"Failed to delete album {request.AlbumId}");
-            }
+        logger.LogInformation("Marked album {AlbumId} as removing", request.AlbumId);
 
-            logger.LogInformation("Deleted album {AlbumId} for user {UserId}", request.AlbumId, request.UserId);
-
-            return new Success();
-        }
+        return Result.Success;
     }
 }

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

@@ -3,36 +3,27 @@ using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Musify.Application.Albums.Responses;
 using Musify.Application.Contracts;
+using Musify.Application.Shared;
 
-namespace Musify.Application.Albums
+namespace Musify.Application.Albums;
+
+public record GetAlbumByIdQuery(Guid Id)
+    : IQuery<ErrorOr<AlbumApplicationResponse>>;
+
+public class GetAlbumByIdQueryHandler(IDatabase database)
+    : IQueryHandler<GetAlbumByIdQuery, ErrorOr<AlbumApplicationResponse>>
 {
-    public record GetAlbumByIdQuery(Guid Id)
-        : IQuery<ErrorOr<AlbumApplicationResponse>>;
-
-    public class GetAlbumByIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetAlbumByIdQuery, ErrorOr<AlbumApplicationResponse>>
+    public async ValueTask<ErrorOr<AlbumApplicationResponse>> Handle(GetAlbumByIdQuery request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<AlbumApplicationResponse>> Handle(GetAlbumByIdQuery request, CancellationToken cancellationToken)
-        {
-            var album = await database.Albums
-                .AsNoTracking()
-                .Where(a => a.Id == request.Id)
-                .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);
+        var album = await database.Albums
+            .AsNoTracking()
+            .Active()
+            .Where(a => a.Id == request.Id)
+            .SelectResponse()
+            .SingleOrDefaultAsync(cancellationToken);
 
-            if (album == null)
-                return Error.NotFound();
-
-            return AlbumApplicationResponse.FromEntity(album.Album, album.TrackCount, album.CoverTrackIds);
-        }
+        return album == null
+            ? AppErrors.NotFound("Album", request.Id)
+            : album;
     }
 }

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

@@ -1,49 +0,0 @@
-using ErrorOr;
-using Mediator;
-using Microsoft.EntityFrameworkCore;
-using MimeMapping;
-using Musify.Application.Configuration;
-using Musify.Application.Contracts;
-
-namespace Musify.Application.Albums
-{
-    public record GetAlbumCoverQuery(Guid AlbumId, string Size)
-        : IQuery<ErrorOr<AlbumCoverLocation>>;
-
-    public record AlbumCoverLocation(string Bucket, string Key, string ContentType);
-
-    public class GetAlbumCoverQueryHandler(
-        IDatabase database,
-        ApplicationStorageConfiguration storageConfiguration,
-        AlbumConfiguration albumConfiguration)
-        : IQueryHandler<GetAlbumCoverQuery, ErrorOr<AlbumCoverLocation>>
-    {
-        public async ValueTask<ErrorOr<AlbumCoverLocation>> Handle(GetAlbumCoverQuery request, CancellationToken cancellationToken)
-        {
-            var pictures = await database.Albums.AsNoTracking()
-                .Where(a => a.Id == request.AlbumId)
-                .Select(a => a.Pictures)
-                .SingleOrDefaultAsync(cancellationToken);
-
-            if (pictures == null)
-                return Error.NotFound();
-
-            var routes = albumConfiguration.Routes;
-            var (name, key) = request.Size.ToLowerInvariant() switch
-            {
-                "small" => (pictures.SmallName, BuildKey(routes.BuildSmallPicturePath, pictures.SmallName)),
-                "large" => (pictures.LargeName, BuildKey(routes.BuildLargePicturePath, pictures.LargeName)),
-                _ => (pictures.MediumName, BuildKey(routes.BuildMediumPicturePath, pictures.MediumName))
-            };
-
-            if (string.IsNullOrEmpty(name) || string.IsNullOrEmpty(key))
-                return Error.NotFound();
-
-            var contentType = MimeUtility.GetMimeMapping(name);
-            return new AlbumCoverLocation(storageConfiguration.Bucket, key, contentType);
-        }
-
-        private static string? BuildKey(Func<string, string> builder, string? name)
-            => string.IsNullOrEmpty(name) ? null : builder(name);
-    }
-}

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

@@ -1,49 +1,38 @@
 using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
+using Musify.Application.Albums.Responses;
 using Musify.Application.Contracts;
 using Musify.Application.Shared;
 using Musify.Application.Tracks.Responses;
-using X.PagedList;
-using X.PagedList.EF;
 
-namespace Musify.Application.Albums
+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 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)
     {
-        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 albumExists = await database.Albums
+            .AsNoTracking()
+            .Active()
+            .AnyAsync(album => album.Id == request.AlbumId, cancellationToken);
+        if (!albumExists)
+            return AppErrors.NotFound("Album", request.AlbumId);
 
-            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);
-
-            var pagedEntities = await tracksQuery
-                .OrderBy(albumTrack => albumTrack.TrackNumber)
-                .Select(albumTrack => new { albumTrack.Track, ListensCount = albumTrack.Track.ListeningHistories.Count(l => l.IsCounted) })
-                .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);
-        }
+        return await database.AlbumHasTracks
+            .AsNoTracking()
+            .Where(albumTrack => albumTrack.AlbumId == request.AlbumId && albumTrack.Track.LifeCycleStatus == Domain.ValueObjects.LifeCycleStatus.Active)
+            .OrderBy(albumTrack => albumTrack.TrackNumber)
+            .ThenBy(albumTrack => albumTrack.Id)
+            .Select(albumTrack => albumTrack.Track)
+            .SelectResponse()
+            .ToPaginatedAsync(new PageRequest(request.PageNumber, request.PageSize), cancellationToken);
     }
 }

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

@@ -1,60 +1,33 @@
-using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Musify.Application.Albums.Responses;
 using Musify.Application.Contracts;
-using X.PagedList;
-using X.PagedList.EF;
+using Musify.Application.Shared;
 
-namespace Musify.Application.Albums
+namespace Musify.Application.Albums;
+
+public record GetAlbumsQuery(string? Title, int PageNumber, int PageSize)
+    : IQuery<PaginatedResponse<AlbumApplicationResponse>>;
+
+public class GetAlbumsQueryHandler(IDatabase database)
+    : IQueryHandler<GetAlbumsQuery, PaginatedResponse<AlbumApplicationResponse>>
 {
-    public record GetAlbumsQuery(string? Title, int PageNumber, int PageSize)
-        : IQuery<ErrorOr<AlbumsSearchResponse>>;
-
-    public class GetAlbumsQueryHandler(IDatabase database)
-        : IQueryHandler<GetAlbumsQuery, ErrorOr<AlbumsSearchResponse>>
+    public async ValueTask<PaginatedResponse<AlbumApplicationResponse>> Handle(GetAlbumsQuery request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<AlbumsSearchResponse>> Handle(GetAlbumsQuery request, CancellationToken cancellationToken)
+        var albumsQuery = database.Albums
+            .AsNoTracking()
+            .Active();
+
+        if (!string.IsNullOrWhiteSpace(request.Title))
         {
-            var albumsQuery = database.Albums
-                .AsNoTracking()
-                .AsQueryable();
-
-            if (!string.IsNullOrEmpty(request.Title))
-            {
-                var normalizedTitle = request.Title.Trim().ToUpperInvariant();
-                albumsQuery = albumsQuery.Where(album => album.NormalizedTitle.Contains(normalizedTitle));
-            }
-
-            var totalCount = await albumsQuery.CountAsync(cancellationToken);
-
-            var pagedEntities = await albumsQuery
-                .OrderByDescending(album => album.CreatedAt)
-                .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 items = pagedEntities
-                .Select(entry => AlbumSearchItemResponse.FromAlbum(
-                    AlbumApplicationResponse.FromEntity(entry.Album, entry.TrackCount, entry.CoverTrackIds)))
-                .ToList();
-
-            return new AlbumsSearchResponse(
-                items,
-                pagedEntities.PageNumber,
-                pagedEntities.PageSize,
-                pagedEntities.PageCount,
-                pagedEntities.TotalItemCount,
-                pagedEntities.HasPreviousPage,
-                pagedEntities.HasNextPage);
+            var normalizedTitle = TextNormalizer.Normalize(request.Title);
+            albumsQuery = albumsQuery.Where(album => album.NormalizedTitle.Contains(normalizedTitle));
         }
+
+        return await albumsQuery
+            .OrderByDescending(album => album.CreatedAt)
+            .ThenBy(album => album.Id)
+            .SelectResponse()
+            .ToPaginatedAsync(new PageRequest(request.PageNumber, request.PageSize), cancellationToken);
     }
 }

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

@@ -4,50 +4,30 @@ using Microsoft.EntityFrameworkCore;
 using Musify.Application.Albums.Responses;
 using Musify.Application.Contracts;
 using Musify.Application.Shared;
-using X.PagedList;
-using X.PagedList.EF;
 
-namespace Musify.Application.Albums
+namespace Musify.Application.Albums;
+
+public record GetAlbumsByUserIdQuery(long UserId, int PageNumber, int PageSize)
+    : IQuery<ErrorOr<PaginatedResponse<AlbumApplicationResponse>>>;
+
+public class GetAlbumsByUserIdQueryHandler(IDatabase database)
+    : IQueryHandler<GetAlbumsByUserIdQuery, ErrorOr<PaginatedResponse<AlbumApplicationResponse>>>
 {
-    public record GetAlbumsByUserIdQuery(long UserId, int PageNumber, int PageSize)
-        : IQuery<ErrorOr<PaginatedResponse<AlbumApplicationResponse>>>;
-
-    public class GetAlbumsByUserIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetAlbumsByUserIdQuery, ErrorOr<PaginatedResponse<AlbumApplicationResponse>>>
+    public async ValueTask<ErrorOr<PaginatedResponse<AlbumApplicationResponse>>> Handle(GetAlbumsByUserIdQuery request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<PaginatedResponse<AlbumApplicationResponse>>> Handle(GetAlbumsByUserIdQuery request, CancellationToken cancellationToken)
-        {
-            var userExists = await database.Users
-                .AsNoTracking()
-                .AnyAsync(user => user.Id == request.UserId, cancellationToken);
-            if (!userExists)
-                return Error.NotFound(description: $"User {request.UserId} not found");
+        var userExists = await database.Users
+            .AsNoTracking()
+            .AnyAsync(user => user.Id == request.UserId, cancellationToken);
+        if (!userExists)
+            return AppErrors.NotFound("User", request.UserId);
 
-            var albumsQuery = database.Albums
-                .AsNoTracking()
-                .Where(album => album.OwnerUserId == request.UserId);
-
-            var totalCount = await albumsQuery.CountAsync(cancellationToken);
-
-            var pagedEntities = await albumsQuery
-                .OrderByDescending(album => album.CreatedAt)
-                .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, entry.CoverTrackIds)),
-                pagedEntities.PageNumber, pagedEntities.PageSize, pagedEntities.TotalItemCount);
-
-            return PaginatedResponse<AlbumApplicationResponse>.FromPagedList(pagedAlbums);
-        }
+        return await database.Albums
+            .AsNoTracking()
+            .Active()
+            .Where(album => album.OwnerUserId == request.UserId)
+            .OrderByDescending(album => album.CreatedAt)
+            .ThenBy(album => album.Id)
+            .SelectResponse()
+            .ToPaginatedAsync(new PageRequest(request.PageNumber, request.PageSize), cancellationToken);
     }
 }

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

@@ -1,61 +1,51 @@
-using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Musify.Application.Albums.Responses;
 using Musify.Application.Contracts;
 
-namespace Musify.Application.Albums
+namespace Musify.Application.Albums;
+
+public record GetRecentlyListenedAlbumsQuery(long UserId, int Limit)
+    : IQuery<IReadOnlyList<AlbumApplicationResponse>>;
+
+public class GetRecentlyListenedAlbumsQueryHandler(IDatabase database)
+    : IQueryHandler<GetRecentlyListenedAlbumsQuery, IReadOnlyList<AlbumApplicationResponse>>
 {
-    public record GetRecentlyListenedAlbumsQuery(long UserId, int Limit)
-        : IQuery<ErrorOr<IReadOnlyList<AlbumApplicationResponse>>>;
-
-    public class GetRecentlyListenedAlbumsQueryHandler(IDatabase database)
-        : IQueryHandler<GetRecentlyListenedAlbumsQuery, ErrorOr<IReadOnlyList<AlbumApplicationResponse>>>
+    public async ValueTask<IReadOnlyList<AlbumApplicationResponse>> Handle(GetRecentlyListenedAlbumsQuery request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<IReadOnlyList<AlbumApplicationResponse>>> Handle(GetRecentlyListenedAlbumsQuery request, CancellationToken cancellationToken)
-        {
-            var listenedTrackIds = database.ListeningHistories
-                .AsNoTracking()
-                .Where(history => history.UserId == request.UserId && history.IsCounted);
+        var listens = database.ListeningHistories
+            .AsNoTracking()
+            .Where(history => history.UserId == request.UserId && history.IsCounted);
 
-            var ranked = await database.AlbumHasTracks
-                .AsNoTracking()
-                .Join(
-                    listenedTrackIds,
-                    albumTrack => albumTrack.TrackId,
-                    history => history.TrackId,
-                    (albumTrack, history) => new { albumTrack.AlbumId, history.ListenedAt })
-                .GroupBy(entry => entry.AlbumId)
-                .Select(group => new { AlbumId = group.Key, LastListenedAt = group.Max(entry => entry.ListenedAt) })
-                .OrderByDescending(entry => entry.LastListenedAt)
-                .Take(request.Limit)
-                .ToListAsync(cancellationToken);
+        var ranked = await database.AlbumHasTracks
+            .AsNoTracking()
+            .Where(albumTrack => albumTrack.Album.LifeCycleStatus == Domain.ValueObjects.LifeCycleStatus.Active)
+            .Join(
+                listens,
+                albumTrack => albumTrack.TrackId,
+                history => history.TrackId,
+                (albumTrack, history) => new { albumTrack.AlbumId, history.ListenedAt })
+            .GroupBy(entry => entry.AlbumId)
+            .Select(group => new { AlbumId = group.Key, LastListenedAt = group.Max(entry => entry.ListenedAt) })
+            .OrderByDescending(entry => entry.LastListenedAt)
+            .ThenBy(entry => entry.AlbumId)
+            .Take(request.Limit)
+            .ToListAsync(cancellationToken);
 
-            if (ranked.Count == 0)
-                return new List<AlbumApplicationResponse>();
+        if (ranked.Count == 0)
+            return [];
 
-            var albumIds = ranked.Select(entry => entry.AlbumId).ToList();
+        var albumIds = ranked.Select(entry => entry.AlbumId).ToList();
 
-            var albums = await database.Albums
-                .AsNoTracking()
-                .Where(album => albumIds.Contains(album.Id))
-                .Select(album => new
-                {
-                    Album = album,
-                    TrackCount = album.AlbumTracks.Count,
-                    CoverTrackIds = album.AlbumTracks
-                        .OrderBy(albumTrack => albumTrack.TrackNumber)
-                        .Take(AlbumApplicationResponse.CoverTrackCount)
-                        .Select(albumTrack => albumTrack.TrackId)
-                        .ToList()
-                })
-                .ToDictionaryAsync(entry => entry.Album.Id, cancellationToken);
+        var albumsById = await database.Albums
+            .AsNoTracking()
+            .Where(album => albumIds.Contains(album.Id))
+            .SelectResponse()
+            .ToDictionaryAsync(album => album.Id, cancellationToken);
 
-            return ranked
-                .Where(entry => albums.ContainsKey(entry.AlbumId))
-                .Select(entry => albums[entry.AlbumId])
-                .Select(entry => AlbumApplicationResponse.FromEntity(entry.Album, entry.TrackCount, entry.CoverTrackIds))
-                .ToList();
-        }
+        return ranked
+            .Where(entry => albumsById.ContainsKey(entry.AlbumId))
+            .Select(entry => albumsById[entry.AlbumId])
+            .ToList();
     }
 }

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

@@ -3,57 +3,43 @@ using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
 using Musify.Application.Contracts;
+using Musify.Application.Shared;
 
-namespace Musify.Application.Albums
+namespace Musify.Application.Albums;
+
+public record RemoveTrackFromAlbumCommand(long UserId, Guid AlbumId, Guid TrackId)
+    : ICommand<ErrorOr<Success>>;
+
+public class RemoveTrackFromAlbumCommandHandler(
+    IDatabase database,
+    ILogger<RemoveTrackFromAlbumCommandHandler> logger)
+    : ICommandHandler<RemoveTrackFromAlbumCommand, ErrorOr<Success>>
 {
-    public record RemoveTrackFromAlbumCommand(long UserId, Guid AlbumId, Guid TrackId)
-        : ICommand<ErrorOr<Success>>;
-
-    public class RemoveTrackFromAlbumCommandHandler(
-        IDatabase database,
-        ILogger<RemoveTrackFromAlbumCommandHandler> logger)
-        : ICommandHandler<RemoveTrackFromAlbumCommand, ErrorOr<Success>>
+    public async ValueTask<ErrorOr<Success>> Handle(RemoveTrackFromAlbumCommand request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<Success>> Handle(RemoveTrackFromAlbumCommand request, CancellationToken cancellationToken)
-        {
-            var album = await database.Albums
-                .AsNoTracking()
-                .SingleOrDefaultAsync(a => a.Id == request.AlbumId, cancellationToken);
-            if (album == null)
-            {
-                logger.LogInformation("Album {AlbumId} not found", request.AlbumId);
-                return Error.NotFound();
-            }
+        var album = await database.Albums.FindOwnedAsync(request.AlbumId, request.UserId, cancellationToken);
+        if (album.IsError)
+            return album.Errors;
 
-            if (album.OwnerUserId != request.UserId)
-            {
-                logger.LogWarning("User {UserId} is not the owner of album {AlbumId}", request.UserId, request.AlbumId);
-                return Error.Unauthorized();
-            }
+        var albumTracks = await database.AlbumHasTracks
+            .Where(albumTrack => albumTrack.AlbumId == request.AlbumId)
+            .OrderBy(albumTrack => albumTrack.TrackNumber)
+            .ToListAsync(cancellationToken);
 
-            var albumTracks = await database.AlbumHasTracks
-                .Where(albumTrack => albumTrack.AlbumId == request.AlbumId)
-                .OrderBy(albumTrack => albumTrack.TrackNumber)
-                .ToListAsync(cancellationToken);
+        var link = albumTracks.SingleOrDefault(albumTrack => albumTrack.TrackId == request.TrackId);
+        if (link == null)
+            return Error.NotFound("Album.TrackNotFound", "Track is not in the album.");
 
-            var link = albumTracks.SingleOrDefault(albumTrack => albumTrack.TrackId == request.TrackId);
-            if (link == null)
-            {
-                logger.LogInformation("Track {TrackId} not in album {AlbumId}", request.TrackId, request.AlbumId);
-                return Error.NotFound(description: "Track is not in the album.");
-            }
+        database.AlbumHasTracks.Remove(link);
 
-            database.AlbumHasTracks.Remove(link);
+        var trackNumber = 1;
+        foreach (var remaining in albumTracks.Where(albumTrack => albumTrack.Id != link.Id))
+            remaining.TrackNumber = trackNumber++;
 
-            var trackNumber = 1;
-            foreach (var remaining in albumTracks.Where(albumTrack => albumTrack.Id != link.Id))
-                remaining.TrackNumber = trackNumber++;
+        await database.SaveChangesAsync(cancellationToken);
 
-            await database.SaveChangesAsync(cancellationToken);
+        logger.LogInformation("Removed track {TrackId} from album {AlbumId}", request.TrackId, request.AlbumId);
 
-            logger.LogInformation("Removed track {TrackId} from album {AlbumId}", request.TrackId, request.AlbumId);
-
-            return new Success();
-        }
+        return Result.Success;
     }
 }

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

@@ -1,105 +1,24 @@
 using ErrorOr;
 using Mediator;
-using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.Logging;
 using Musify.Application.Configuration;
-using Musify.Application.Albums.Responses;
+using Musify.Application.Pictures.Responses;
 using Musify.Application.Services;
-using Musify.Domain.Entities;
 using Musify.Domain.ValueObjects;
-using Musify.Application.Contracts;
 
-namespace Musify.Application.Albums
+namespace Musify.Application.Albums;
+
+public record RequestAlbumPictureUploadCommand(
+    long UserId,
+    string FileType,
+    string ContentType,
+    long? ExpectedSizeBytes = null)
+    : ICommand<ErrorOr<PictureUploadResponse>>;
+
+public class RequestAlbumPictureUploadCommandHandler(UploadIntentIssuer issuer, AlbumConfiguration albumConfiguration)
+    : ICommandHandler<RequestAlbumPictureUploadCommand, ErrorOr<PictureUploadResponse>>
 {
-    public record RequestAlbumPictureUploadCommand(
-        long UserId,
-        string FileType,
-        string ContentType,
-        long? ExpectedSizeBytes = null)
-        : ICommand<ErrorOr<AlbumPictureUploadResponse>>;
-
-    public class RequestAlbumPictureUploadCommandHandler(
-        IDatabase database,
-        UploadIntentValidator uploadIntentValidator,
-        IStorageService storageService,
-        ILogger<RequestAlbumPictureUploadCommandHandler> logger,
-        ApplicationStorageConfiguration storageConfiguration,
-        AlbumConfiguration albumConfiguration,
-        UploadIntentConfiguration uploadIntentConfiguration)
-        : ICommandHandler<RequestAlbumPictureUploadCommand, ErrorOr<AlbumPictureUploadResponse>>
-    {
-        public async ValueTask<ErrorOr<AlbumPictureUploadResponse>> Handle(RequestAlbumPictureUploadCommand request, CancellationToken cancellationToken)
-        {
-            var userExists = await database.Users
-                .AsNoTracking()
-                .AnyAsync(u => u.Id == request.UserId, cancellationToken);
-            if (!userExists)
-            {
-                logger.LogWarning("User {UserId} not found", request.UserId);
-                return Error.NotFound(description: $"User {request.UserId} not found");
-            }
-
-            var effectiveSizeBytes = request.ExpectedSizeBytes
-                ?? uploadIntentConfiguration.DefaultExpectedPictureSizeBytes;
-
-            var objectName = $"{Guid.NewGuid()}.{request.FileType.TrimStart('.').ToLowerInvariant()}";
-
-            var tempKey = albumConfiguration.Routes.BuildTempPicturePath(
-                uploadIntentConfiguration.TemporalRootPrefix, request.UserId, objectName);
-
-            try
-            {
-                var uploadUrl = await storageService.GetUploadUrlAsync(
-                    storageConfiguration.Bucket,
-                    tempKey,
-                    request.ContentType,
-                    TimeSpan.FromSeconds(uploadIntentConfiguration.UploadUrlExpiresInSeconds),
-                    cancellationToken);
-
-                await using var transaction = await database.BeginTransactionAsync(
-                    System.Data.IsolationLevel.Serializable, cancellationToken);
-
-                var quotaCheck = await uploadIntentValidator.CheckQuotaAsync(
-                    uploadIntentConfiguration,
-                    request.UserId, effectiveSizeBytes, 1, cancellationToken);
-                if (quotaCheck.IsError)
-                {
-                    logger.LogWarning("User {UserId} failed upload intent quota check", request.UserId);
-                    return quotaCheck.Errors;
-                }
-
-                var intent = new UploadIntent
-                {
-                    UserId = request.UserId,
-                    Bucket = storageConfiguration.Bucket,
-                    Key = tempKey,
-                    ObjectName = objectName,
-                    ContentType = request.ContentType,
-                    ExpectedSizeBytes = effectiveSizeBytes,
-                    Purpose = UploadIntentPurpose.AlbumPicture,
-                    ExpiresAt = DateTime.UtcNow.AddSeconds(uploadIntentConfiguration.UploadUrlExpiresInSeconds),
-                };
-
-                await database.UploadIntents.AddAsync(intent, cancellationToken);
-                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);
-
-                return new AlbumPictureUploadResponse(
-                    intent.Id,
-                    storageConfiguration.Bucket,
-                    tempKey,
-                    objectName,
-                    request.ContentType,
-                    uploadIntentConfiguration.UploadUrlExpiresInSeconds,
-                    uploadUrl);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to generate album picture upload URL for user {UserId}", request.UserId);
-                return Error.Failure(description: "Failed to generate upload URL");
-            }
-        }
-    }
+    public async ValueTask<ErrorOr<PictureUploadResponse>> Handle(RequestAlbumPictureUploadCommand request, CancellationToken cancellationToken) =>
+        await issuer.IssuePictureAsync(
+            request.UserId, UploadIntentPurpose.AlbumPicture, albumConfiguration,
+            request.FileType, request.ContentType, request.ExpectedSizeBytes, cancellationToken);
 }

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

@@ -1,43 +1,40 @@
-using System.Text.Json.Serialization;
 using Musify.Domain.Entities;
-using Musify.Application.Serialization;
 
-namespace Musify.Application.Albums.Responses
+namespace Musify.Application.Albums.Responses;
+
+public record AlbumApplicationResponse(
+    Guid Id,
+    string Title,
+    string? Description,
+    int? ReleaseYear,
+    long OwnerUserId,
+    int TrackCount,
+    string? SmallImageKeyName,
+    string? MediumImageKeyName,
+    string? LargeImageKeyName,
+    DateTime CreatedAt,
+    DateTime UpdatedAt,
+    IReadOnlyList<Guid> CoverTrackIds)
 {
-    public record AlbumApplicationResponse(
-        Guid Id,
-        string Title,
-        string? Description,
-        int? ReleaseYear,
-        [property: JsonConverter(typeof(LongAsStringConverter))] long OwnerUserId,
-        int TrackCount,
-        string? SmallImageKeyName,
-        string? MediumImageKeyName,
-        string? LargeImageKeyName,
-        DateTime CreatedAt,
-        DateTime UpdatedAt,
-        IReadOnlyList<Guid> CoverTrackIds)
-    {
-        public const int CoverTrackCount = 4;
+    public const int CoverTrackCount = AlbumProjections.CoverTrackCount;
 
-        public static AlbumApplicationResponse FromEntity(
-            Album album,
-            int trackCount,
-            IReadOnlyList<Guid>? coverTrackIds = null)
-        {
-            return new AlbumApplicationResponse(
-                album.Id,
-                album.Title,
-                album.Description,
-                album.ReleaseYear,
-                album.OwnerUserId,
-                trackCount,
-                album.Pictures?.SmallName,
-                album.Pictures?.MediumName,
-                album.Pictures?.LargeName,
-                album.CreatedAt,
-                album.UpdatedAt,
-                coverTrackIds ?? []);
-        }
+    public static AlbumApplicationResponse FromEntity(
+        Album album,
+        int trackCount,
+        IReadOnlyList<Guid>? coverTrackIds = null)
+    {
+        return new AlbumApplicationResponse(
+            album.Id,
+            album.Title,
+            album.Description,
+            album.ReleaseYear,
+            album.OwnerUserId,
+            trackCount,
+            album.Pictures?.SmallName,
+            album.Pictures?.MediumName,
+            album.Pictures?.LargeName,
+            album.CreatedAt,
+            album.UpdatedAt,
+            coverTrackIds ?? []);
     }
 }

backend/Core/Musify.Application/Albums/Responses/AlbumPictureUploadResponse.cs

@@ -1,11 +0,0 @@
-namespace Musify.Application.Albums.Responses
-{
-    public record AlbumPictureUploadResponse(
-        Guid IntentId,
-        string Bucket,
-        string Key,
-        string PictureName,
-        string ContentType,
-        int ExpiresInSeconds,
-        string UploadUrl);
-}

backend/Core/Musify.Application/Albums/Responses/AlbumProjections.cs

@@ -0,0 +1,31 @@
+using Musify.Domain.Entities;
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.Albums.Responses;
+
+public static class AlbumProjections
+{
+    public const int CoverTrackCount = 4;
+
+    public static IQueryable<Album> Active(this IQueryable<Album> query) =>
+        query.Where(album => album.LifeCycleStatus == LifeCycleStatus.Active);
+
+    public static IQueryable<AlbumApplicationResponse> SelectResponse(this IQueryable<Album> query) =>
+        query.Select(album => new AlbumApplicationResponse(
+            album.Id,
+            album.Title,
+            album.Description,
+            album.ReleaseYear,
+            album.OwnerUserId,
+            album.AlbumTracks.Count,
+            album.Pictures!.SmallName,
+            album.Pictures!.MediumName,
+            album.Pictures!.LargeName,
+            album.CreatedAt,
+            album.UpdatedAt,
+            album.AlbumTracks
+                .OrderBy(albumTrack => albumTrack.TrackNumber)
+                .Take(CoverTrackCount)
+                .Select(albumTrack => albumTrack.TrackId)
+                .ToList()));
+}

backend/Core/Musify.Application/Albums/Responses/AlbumSearchItemResponse.cs

@@ -1,7 +0,0 @@
-namespace Musify.Application.Albums.Responses
-{
-    public record AlbumSearchItemResponse(AlbumApplicationResponse Album)
-    {
-        public static AlbumSearchItemResponse FromAlbum(AlbumApplicationResponse album) => new(album);
-    }
-}

backend/Core/Musify.Application/Albums/Responses/AlbumsSearchResponse.cs

@@ -1,12 +0,0 @@
-namespace Musify.Application.Albums.Responses
-{
-
-    public record AlbumsSearchResponse(
-        IReadOnlyList<AlbumSearchItemResponse> Items,
-        int PageNumber,
-        int PageSize,
-        int PageCount,
-        int TotalItemCount,
-        bool HasPreviousPage,
-        bool HasNextPage);
-}

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

@@ -2,149 +2,72 @@ using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
-using Musify.Application.Configuration;
-using Musify.Application.Shared;
-using Musify.Application.Events;
 using Musify.Application.Albums.Responses;
-using Musify.Application.Services;
-using Musify.Domain.Entities;
-using Musify.Domain.ValueObjects;
+using Musify.Application.Configuration;
 using Musify.Application.Contracts;
+using Musify.Application.Events;
+using Musify.Application.Pictures;
+using Musify.Application.Services;
+using Musify.Application.Shared;
+using Musify.Domain.ValueObjects;
 
-namespace Musify.Application.Albums
+namespace Musify.Application.Albums;
+
+public record UpdateAlbumCommand(
+    long UserId,
+    Guid AlbumId,
+    string Title,
+    string? Description,
+    int? ReleaseYear,
+    Guid? NewPictureIntentId)
+    : ICommand<ErrorOr<AlbumApplicationResponse>>;
+
+public class UpdateAlbumCommandHandler(
+    IEventBus eventBus,
+    IDatabase database,
+    UploadIntentValidator uploadIntentValidator,
+    ILogger<UpdateAlbumCommandHandler> logger,
+    AlbumConfiguration albumConfiguration)
+    : ICommandHandler<UpdateAlbumCommand, ErrorOr<AlbumApplicationResponse>>
 {
-    public record UpdateAlbumCommand(
-        long UserId,
-        Guid AlbumId,
-        string Title,
-        string? Description,
-        int? ReleaseYear,
-        Guid? NewPictureIntentId)
-        : ICommand<ErrorOr<AlbumApplicationResponse>>;
-
-    public class UpdateAlbumCommandHandler(
-        IEventBus eventBus,
-        IDatabase database,
-        UploadIntentValidator uploadIntentValidator,
-        ILogger<UpdateAlbumCommandHandler> logger,
-        ApplicationStorageConfiguration storageConfiguration,
-        AlbumConfiguration albumConfiguration,
-        UploadIntentConfiguration uploadIntentConfiguration)
-        : ICommandHandler<UpdateAlbumCommand, ErrorOr<AlbumApplicationResponse>>
+    public async ValueTask<ErrorOr<AlbumApplicationResponse>> Handle(UpdateAlbumCommand request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<AlbumApplicationResponse>> Handle(UpdateAlbumCommand request, CancellationToken cancellationToken)
+        var found = await database.Albums.FindOwnedAsync(request.AlbumId, request.UserId, cancellationToken);
+        if (found.IsError)
+            return found.Errors;
+
+        var album = found.Value;
+        var title = request.Title.Trim();
+
+        album.Title = title;
+        album.NormalizedTitle = TextNormalizer.Normalize(title);
+        album.Description = request.Description;
+        album.ReleaseYear = request.ReleaseYear;
+
+        if (request.NewPictureIntentId is { } intentId)
         {
-            var album = await database.Albums
-                .SingleOrDefaultAsync(a => a.Id == request.AlbumId, cancellationToken);
-            if (album == null)
-            {
-                logger.LogInformation("Album {AlbumId} not found", request.AlbumId);
-                return Error.NotFound();
-            }
+            var prepared = await PictureSourceChange.PrepareAsync(
+                uploadIntentValidator, intentId, request.UserId, UploadIntentPurpose.AlbumPicture, albumConfiguration, cancellationToken);
+            if (prepared.IsError)
+                return prepared.Errors;
 
-            if (album.OwnerUserId != request.UserId)
-            {
-                logger.LogWarning("Album {AlbumId} does not belong to user {UserId}", request.AlbumId, request.UserId);
-                return Error.Unauthorized();
-            }
+            var picture = prepared.Value;
+            album.Pictures = picture.Pictures;
 
-            var title = request.Title.Trim();
-
-            album.Title = title;
-            album.NormalizedTitle = title.ToUpperInvariant();
-            album.Description = request.Description;
-            album.ReleaseYear = request.ReleaseYear;
-
-            UploadIntent? pictureIntent = null;
-            string? finalPictureKey = null;
-
-            if (request.NewPictureIntentId.HasValue)
-            {
-                var validation = await uploadIntentValidator.ValidateAndLoadAsync(
-                    uploadIntentConfiguration,
-                    request.NewPictureIntentId.Value, request.UserId, cancellationToken);
-                if (validation.IsError)
-                    return validation.Errors;
-
-                pictureIntent = validation.Value;
-                album.Pictures = new AlbumPictures
-                {
-                    OriginalName = pictureIntent.ObjectName,
-                    SmallName = pictureIntent.ObjectName,
-                    MediumName = pictureIntent.ObjectName,
-                    LargeName = pictureIntent.ObjectName
-                };
-                finalPictureKey = albumConfiguration.Routes.BuildOriginalPicturePath(request.UserId, pictureIntent.ObjectName);
-            }
-
-            if (pictureIntent != null && finalPictureKey != null)
-            {
-                var publishResult = await PublishUpdateAlbumPictureSourceEventAsync(
-                    album.Id, pictureIntent, finalPictureKey, cancellationToken);
-                if (publishResult.IsError)
-                    return publishResult.Errors;
-            }
-
-            try
-            {
-                await database.SaveChangesAsync(cancellationToken);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to update album {AlbumId}", request.AlbumId);
-                return Error.Failure(description: $"Failed to update album {request.AlbumId}");
-            }
-
-            var albumTracks = database.AlbumHasTracks
-                .AsNoTracking()
-                .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("Updated album {AlbumId}", album.Id);
-            return AlbumApplicationResponse.FromEntity(album, trackCount, coverTrackIds);
+            await eventBus.PublishAsync(
+                new UpdateAlbumPictureSourceEvent(
+                    album.Id, picture.Intent.Id, picture.Intent.Bucket, picture.Intent.Key, picture.FinalKey, picture.Sizes),
+                cancellationToken);
         }
 
-        private async Task<ErrorOr<Success>> PublishUpdateAlbumPictureSourceEventAsync(
-            Guid albumId,
-            UploadIntent pictureIntent,
-            string finalPictureKey,
-            CancellationToken cancellationToken)
-        {
-            try
-            {
-                await eventBus.PublishAsync(
-                    new UpdateAlbumPictureSourceEvent(
-                        albumId,
-                        pictureIntent.Id,
-                        storageConfiguration.Bucket,
-                        pictureIntent.Key,
-                        finalPictureKey,
-                        new ImageSize(
-                            albumConfiguration.Routes.SmallPicturesPath,
-                            albumConfiguration.PicturesSizes.SmallPictureWidth,
-                            albumConfiguration.PicturesSizes.SmallPictureHeight),
-                        new ImageSize(
-                            albumConfiguration.Routes.MediumPicturesPath,
-                            albumConfiguration.PicturesSizes.MediumPictureWidth,
-                            albumConfiguration.PicturesSizes.MediumPictureHeight),
-                        new ImageSize(
-                            albumConfiguration.Routes.LargePicturesPath,
-                            albumConfiguration.PicturesSizes.LargePictureWidth,
-                            albumConfiguration.PicturesSizes.LargePictureHeight)),
-                    cancellationToken);
-                return new Success();
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to publish update album picture source event for album {AlbumId}", albumId);
-                return Error.Failure(description: $"Failed to publish update album picture source event for album {albumId}");
-            }
-        }
+        await database.SaveChangesAsync(cancellationToken);
+
+        logger.LogInformation("Updated album {AlbumId}", album.Id);
+
+        return await database.Albums
+            .AsNoTracking()
+            .Where(a => a.Id == album.Id)
+            .SelectResponse()
+            .SingleAsync(cancellationToken);
     }
 }

backend/Core/Musify.Application/Application.csproj

@@ -19,8 +19,6 @@
     <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" />
     <PackageReference Include="Microsoft.Extensions.Options.DataAnnotations" />
     <PackageReference Include="MimeMapping" />
-    <PackageReference Include="X.PagedList" />
-    <PackageReference Include="X.PagedList.EF" />
   </ItemGroup>
 
   <ItemGroup>

backend/Core/Musify.Application/ApplicationDependencyInjection.cs

@@ -11,16 +11,17 @@ public static class ApplicationDependencyInjection
     {
         services.AddMediator();
         services.AddScoped<UploadIntentValidator>();
+        services.AddScoped<UploadIntentIssuer>();
         services.AddScoped<TrackStreamIssuer>();
 
-        services.AddValidatedOptions<ApplicationStorageConfiguration>(configuration, ApplicationStorageConfiguration.SectionName);
-        services.AddValidatedOptions<PlayListConfiguration>(configuration, PlayListConfiguration.SectionName);
-        services.AddValidatedOptions<AlbumConfiguration>(configuration, AlbumConfiguration.SectionName);
-        services.AddValidatedOptions<TrackConfiguration>(configuration, TrackConfiguration.SectionName);
-        services.AddValidatedOptions<MixConfiguration>(configuration, MixConfiguration.SectionName);
-        services.AddValidatedOptions<StreamGatewayConfiguration>(configuration, StreamGatewayConfiguration.SectionName);
-        services.AddValidatedOptions<UploadIntentConfiguration>(configuration, UploadIntentConfiguration.SectionName);
-        services.AddValidatedOptions<PlaybackConfiguration>(configuration, PlaybackConfiguration.SectionName);
+        services.AddValidatedOptions<ApplicationStorageConfiguration>(configuration);
+        services.AddValidatedOptions<PlayListConfiguration>(configuration);
+        services.AddValidatedOptions<AlbumConfiguration>(configuration);
+        services.AddValidatedOptions<TrackConfiguration>(configuration);
+        services.AddValidatedOptions<MixConfiguration>(configuration);
+        services.AddValidatedOptions<StreamGatewayConfiguration>(configuration);
+        services.AddValidatedOptions<UploadIntentConfiguration>(configuration);
+        services.AddValidatedOptions<PlaybackConfiguration>(configuration);
 
         return services;
     }

backend/Core/Musify.Application/AssemblyInfo.cs

@@ -1,4 +1,4 @@
-using Mediator;
+using Mediator;
 using Microsoft.Extensions.DependencyInjection;
 
-[assembly: MediatorOptions(ServiceLifetime = ServiceLifetime.Scoped)]
+[assembly: MediatorOptions(ServiceLifetime = ServiceLifetime.Scoped)]

backend/Core/Musify.Application/Configuration/AlbumConfiguration.cs

@@ -1,79 +1,14 @@
 using System.ComponentModel.DataAnnotations;
-using Musify.Application.Shared;
 
-namespace Musify.Application.Configuration
+namespace Musify.Application.Configuration;
+
+public class AlbumConfiguration : IConfigurationOptions, IPictureOwnerConfiguration
 {
-    public class AlbumConfiguration
-    {
-        public const string SectionName = "Album";
+    public static string SectionName => "Album";
 
-        [Required]
-        public AlbumRoutes Routes { get; set; } = new AlbumRoutes();
+    [Required]
+    public PictureRoutes Routes { get; set; } = new() { ParentFolder = "Albums" };
 
-        [Required]
-        public AlbumPicturesSizes PicturesSizes { get; set; } = new AlbumPicturesSizes();
-    }
-
-    public class AlbumRoutes
-    {
-        [Required]
-        public string UploadsFolder { get; set; } = "uploads";
-
-        [Required]
-        public string ParentFolders { get; set; } = "Albums";
-
-        [Required]
-        public string OriginalPicturesFolder { get; set; } = "OriginalPictures";
-
-        [Required]
-        public string SmallPicturesFolder { get; set; } = "SmallPictures";
-
-        [Required]
-        public string MediumPicturesFolder { get; set; } = "MediumPictures";
-
-        [Required]
-        public string LargePicturesFolder { get; set; } = "LargePictures";
-
-        public string SmallPicturesPath => StorageKey.Combine(ParentFolders, SmallPicturesFolder);
-
-        public string MediumPicturesPath => StorageKey.Combine(ParentFolders, MediumPicturesFolder);
-
-        public string LargePicturesPath => StorageKey.Combine(ParentFolders, LargePicturesFolder);
-
-        public string OriginalPicturesPath => StorageKey.Combine(ParentFolders, OriginalPicturesFolder);
-
-        public string BuildOriginalPicturePath(string pictureName) => StorageKey.Combine(ParentFolders, OriginalPicturesFolder, pictureName);
-
-        public string BuildOriginalPicturePath(long userId, string pictureName) => StorageKey.Combine(UploadsFolder, userId.ToString(), ParentFolders, OriginalPicturesFolder, pictureName);
-
-        public string BuildSmallPicturePath(string pictureName) => StorageKey.Combine(ParentFolders, SmallPicturesFolder, pictureName);
-
-        public string BuildMediumPicturePath(string pictureName) => StorageKey.Combine(ParentFolders, MediumPicturesFolder, pictureName);
-
-        public string BuildLargePicturePath(string pictureName) => StorageKey.Combine(ParentFolders, LargePicturesFolder, pictureName);
-
-        public string BuildTempPicturePath(string tempRootPrefix, long userId, string objectName) =>
-            StorageKey.Combine(tempRootPrefix, userId.ToString(), ParentFolders, objectName);
-    }
-
-    public class AlbumPicturesSizes
-    {
-        [Range(1, 1024)]
-        public int SmallPictureWidth { get; set; } = 128;
-
-        [Range(1, 1024)]
-        public int SmallPictureHeight { get; set; } = 128;
-
-        [Range(1, 1024)]
-        public int MediumPictureWidth { get; set; } = 256;
-
-        [Range(1, 1024)]
-        public int MediumPictureHeight { get; set; } = 256;
-
-        [Range(1, 1024)]
-        public int LargePictureWidth { get; set; } = 512;
-
-        [Range(1, 1024)]
-        public int LargePictureHeight { get; set; } = 512;
-    }
+    [Required]
+    public PictureSizes PicturesSizes { get; set; } = new();
 }

backend/Core/Musify.Application/Configuration/ApplicationStorageConfiguration.cs

@@ -1,13 +1,12 @@
 using System.ComponentModel.DataAnnotations;
 
-namespace Musify.Application.Configuration
-{
-    public class ApplicationStorageConfiguration
-    {
-        public const string SectionName = "ApplicationStorage";
+namespace Musify.Application.Configuration;
 
-        [Required]
-        [StringLength(128, MinimumLength = 1)]
-        public required string Bucket { get; set; }
-    }
+public class ApplicationStorageConfiguration : IConfigurationOptions
+{
+    public static string SectionName => "ApplicationStorage";
+
+    [Required]
+    [StringLength(128, MinimumLength = 1)]
+    public required string Bucket { get; set; }
 }

backend/Core/Musify.Application/Configuration/ConfigurationDependencyInjection.cs

@@ -6,6 +6,10 @@ namespace Musify.Application.Configuration;
 
 public static class ConfigurationDependencyInjection
 {
+    public static IServiceCollection AddValidatedOptions<T>(this IServiceCollection services, IConfiguration configuration)
+        where T : class, IConfigurationOptions =>
+        services.AddValidatedOptions<T>(configuration, T.SectionName);
+
     public static IServiceCollection AddValidatedOptions<T>(
         this IServiceCollection services,
         IConfiguration configuration,

backend/Core/Musify.Application/Configuration/GetPlaybackPublicConfig.cs

@@ -1,17 +1,16 @@
 using Mediator;
 using Musify.Application.Configuration.Responses;
 
-namespace Musify.Application.Configuration
+namespace Musify.Application.Configuration;
+
+
+public record GetPlaybackPublicConfigQuery : IQuery<PlaybackPublicConfigResponse>;
+
+public class GetPlaybackPublicConfigQueryHandler(PlaybackConfiguration playbackConfiguration)
+    : IQueryHandler<GetPlaybackPublicConfigQuery, PlaybackPublicConfigResponse>
 {
-
-    public record GetPlaybackPublicConfigQuery : IQuery<PlaybackPublicConfigResponse>;
-
-    public class GetPlaybackPublicConfigQueryHandler(PlaybackConfiguration playbackConfiguration)
-        : IQueryHandler<GetPlaybackPublicConfigQuery, PlaybackPublicConfigResponse>
-    {
-        public ValueTask<PlaybackPublicConfigResponse> Handle(GetPlaybackPublicConfigQuery query, CancellationToken cancellationToken) =>
-            ValueTask.FromResult(new PlaybackPublicConfigResponse(
-                playbackConfiguration.AllowAnonymousListening,
-                playbackConfiguration.AnonymousFragmentSeconds));
-    }
+    public ValueTask<PlaybackPublicConfigResponse> Handle(GetPlaybackPublicConfigQuery query, CancellationToken cancellationToken) =>
+        ValueTask.FromResult(new PlaybackPublicConfigResponse(
+            playbackConfiguration.AllowAnonymousListening,
+            playbackConfiguration.AnonymousFragmentSeconds));
 }

backend/Core/Musify.Application/Configuration/IConfigurationOptions.cs

@@ -0,0 +1,6 @@
+namespace Musify.Application.Configuration;
+
+public interface IConfigurationOptions
+{
+    public static abstract string SectionName { get; }
+}

backend/Core/Musify.Application/Configuration/MixConfiguration.cs

@@ -1,12 +1,11 @@
 using System.ComponentModel.DataAnnotations;
 
-namespace Musify.Application.Configuration
-{
-    public class MixConfiguration
-    {
-        public const string SectionName = "Mix";
+namespace Musify.Application.Configuration;
 
-        [Range(4, 100)]
-        public int ItemsPerMix { get; set; } = 12;
-    }
+public class MixConfiguration : IConfigurationOptions
+{
+    public static string SectionName => "Mix";
+
+    [Range(4, 100)]
+    public int ItemsPerMix { get; set; } = 12;
 }

backend/Core/Musify.Application/Configuration/Pictures.cs

@@ -0,0 +1,90 @@
+using System.ComponentModel.DataAnnotations;
+using Musify.Application.Shared;
+
+namespace Musify.Application.Configuration;
+
+public enum PictureSize
+{
+    Small,
+    Medium,
+    Large
+}
+
+public class PictureRoutes
+{
+    [Required]
+    public string UploadsFolder { get; set; } = "uploads";
+
+    [Required]
+    public string ParentFolder { get; set; } = string.Empty;
+
+    [Required]
+    public string OriginalPicturesFolder { get; set; } = "OriginalPictures";
+
+    [Required]
+    public string SmallPicturesFolder { get; set; } = "SmallPictures";
+
+    [Required]
+    public string MediumPicturesFolder { get; set; } = "MediumPictures";
+
+    [Required]
+    public string LargePicturesFolder { get; set; } = "LargePictures";
+
+    public string FolderPath(PictureSize size) => StorageKey.Combine(ParentFolder, size switch
+    {
+        PictureSize.Small => SmallPicturesFolder,
+        PictureSize.Medium => MediumPicturesFolder,
+        PictureSize.Large => LargePicturesFolder,
+        _ => throw new ArgumentOutOfRangeException(nameof(size), size, null)
+    });
+
+    public string BuildPicturePath(PictureSize size, string pictureName) => StorageKey.Combine(FolderPath(size), pictureName);
+
+    public string BuildOriginalPicturePath(long userId, string pictureName) =>
+        StorageKey.Combine(UploadsFolder, userId.ToString(), ParentFolder, OriginalPicturesFolder, pictureName);
+
+    public string BuildTempPath(string tempRootPrefix, long userId, string objectName) =>
+        StorageKey.Combine(tempRootPrefix, userId.ToString(), ParentFolder, objectName);
+}
+
+public class PictureSizes
+{
+    [Range(1, 1024)]
+    public int SmallWidth { get; set; } = 128;
+
+    [Range(1, 1024)]
+    public int SmallHeight { get; set; } = 128;
+
+    [Range(1, 1024)]
+    public int MediumWidth { get; set; } = 256;
+
+    [Range(1, 1024)]
+    public int MediumHeight { get; set; } = 256;
+
+    [Range(1, 1024)]
+    public int LargeWidth { get; set; } = 512;
+
+    [Range(1, 1024)]
+    public int LargeHeight { get; set; } = 512;
+
+    public ImageSizes ToImageSizes(PictureRoutes routes) => new(
+        new ImageSize(routes.FolderPath(PictureSize.Small), SmallWidth, SmallHeight),
+        new ImageSize(routes.FolderPath(PictureSize.Medium), MediumWidth, MediumHeight),
+        new ImageSize(routes.FolderPath(PictureSize.Large), LargeWidth, LargeHeight));
+}
+
+public interface IPictureOwnerConfiguration
+{
+    public PictureRoutes Routes { get; }
+
+    public PictureSizes PicturesSizes { get; }
+}
+
+public static class PictureSizeParser
+{
+    /// <summary>Parses the <c>size</c> query value; anything unknown means <see cref="PictureSize.Medium"/>.</summary>
+    public static PictureSize Parse(string? value) =>
+        Enum.TryParse<PictureSize>(value, ignoreCase: true, out var size) && Enum.IsDefined(size)
+            ? size
+            : PictureSize.Medium;
+}

backend/Core/Musify.Application/Configuration/PlayListConfiguration.cs

@@ -1,79 +1,14 @@
 using System.ComponentModel.DataAnnotations;
-using Musify.Application.Shared;
 
-namespace Musify.Application.Configuration
+namespace Musify.Application.Configuration;
+
+public class PlayListConfiguration : IConfigurationOptions, IPictureOwnerConfiguration
 {
-    public class PlayListConfiguration
-    {
-        public const string SectionName = "PlayList";
+    public static string SectionName => "PlayList";
 
-        [Required]
-        public PlayListRoutes Routes { get; set; } = new PlayListRoutes();
+    [Required]
+    public PictureRoutes Routes { get; set; } = new() { ParentFolder = "PlayLists" };
 
-        [Required]
-        public PlayListPicturesSizes PicturesSizes { get; set; } = new PlayListPicturesSizes();
-    }
-
-    public class PlayListRoutes
-    {
-        [Required]
-        public string UploadsFolder { get; set; } = "uploads";
-
-        [Required]
-        public string ParentFolders { get; set; } = "PlayLists";
-
-        [Required]
-        public string OriginalPicturesFolder { get; set; } = "OriginalPictures";
-
-        [Required]
-        public string SmallPicturesFolder { get; set; } = "SmallPictures";
-
-        [Required]
-        public string MediumPicturesFolder { get; set; } = "MediumPictures";
-
-        [Required]
-        public string LargePicturesFolder { get; set; } = "LargePictures";
-
-        public string SmallPicturesPath => StorageKey.Combine(ParentFolders, SmallPicturesFolder);
-
-        public string MediumPicturesPath => StorageKey.Combine(ParentFolders, MediumPicturesFolder);
-
-        public string LargePicturesPath => StorageKey.Combine(ParentFolders, LargePicturesFolder);
-
-        public string OriginalPicturesPath => StorageKey.Combine(ParentFolders, OriginalPicturesFolder);
-
-        public string BuildOriginalPicturePath(string pictureName) => StorageKey.Combine(ParentFolders, OriginalPicturesFolder, pictureName);
-
-        public string BuildOriginalPicturePath(long userId, string pictureName) => StorageKey.Combine(UploadsFolder, userId.ToString(), ParentFolders, OriginalPicturesFolder, pictureName);
-
-        public string BuildSmallPicturePath(string pictureName) => StorageKey.Combine(ParentFolders, SmallPicturesFolder, pictureName);
-
-        public string BuildMediumPicturePath(string pictureName) => StorageKey.Combine(ParentFolders, MediumPicturesFolder, pictureName);
-
-        public string BuildLargePicturePath(string pictureName) => StorageKey.Combine(ParentFolders, LargePicturesFolder, pictureName);
-
-        public string BuildTempPicturePath(string tempRootPrefix, long userId, string objectName) =>
-            StorageKey.Combine(tempRootPrefix, userId.ToString(), ParentFolders, objectName);
-    }
-
-    public class PlayListPicturesSizes
-    {
-        [Range(1, 1024)]
-        public int SmallPictureWidth { get; set; } = 128;
-
-        [Range(1, 1024)]
-        public int SmallPictureHeight { get; set; } = 128;
-
-        [Range(1, 1024)]
-        public int MediumPictureWidth { get; set; } = 256;
-
-        [Range(1, 1024)]
-        public int MediumPictureHeight { get; set; } = 256;
-
-        [Range(1, 1024)]
-        public int LargePictureWidth { get; set; } = 512;
-
-        [Range(1, 1024)]
-        public int LargePictureHeight { get; set; } = 512;
-    }
-}
+    [Required]
+    public PictureSizes PicturesSizes { get; set; } = new();
+}

backend/Core/Musify.Application/Configuration/PlaybackConfiguration.cs

@@ -1,18 +1,17 @@
 using System.ComponentModel.DataAnnotations;
 
-namespace Musify.Application.Configuration
+namespace Musify.Application.Configuration;
+
+
+public sealed class PlaybackConfiguration : IConfigurationOptions
 {
+    public static string SectionName => "Playback";
 
-    public sealed class PlaybackConfiguration
-    {
-        public const string SectionName = "Playback";
+    public bool AllowAnonymousListening { get; set; }
 
-        public bool AllowAnonymousListening { get; set; }
+    [Range(0, 3600)]
+    public int AnonymousFragmentSeconds { get; set; }
 
-        [Range(0, 3600)]
-        public int AnonymousFragmentSeconds { get; set; }
-
-        [Range(1, int.MaxValue)]
-        public int EstimatedAudioBytesPerSecond { get; set; } = 16_000;
-    }
+    [Range(1, int.MaxValue)]
+    public int EstimatedAudioBytesPerSecond { get; set; } = 16_000;
 }

backend/Core/Musify.Application/Configuration/Responses/PlaybackPublicConfigResponse.cs

@@ -1,5 +1,4 @@
-namespace Musify.Application.Configuration.Responses
-{
+namespace Musify.Application.Configuration.Responses;
 
-    public record PlaybackPublicConfigResponse(bool AllowAnonymousListening, int AnonymousFragmentSeconds);
-}
+
+public record PlaybackPublicConfigResponse(bool AllowAnonymousListening, int AnonymousFragmentSeconds);

backend/Core/Musify.Application/Configuration/StreamGatewayConfiguration.cs

@@ -1,16 +1,15 @@
 using System.ComponentModel.DataAnnotations;
 
-namespace Musify.Application.Configuration
+namespace Musify.Application.Configuration;
+
+public class StreamGatewayConfiguration : IConfigurationOptions
 {
-    public class StreamGatewayConfiguration
-    {
-        public const string SectionName = "StreamGateway";
+    public static string SectionName => "StreamGateway";
 
-        [Url]
-        [Required]
-        public required string PublicBaseUrl { get; set; }
+    [Url]
+    [Required]
+    public required string PublicBaseUrl { get; set; }
 
-        [Required]
-        public string AudioFileName { get; set; } = "audio.m4a";
-    }
+    [Required]
+    public string AudioFileName { get; set; } = "audio.m4a";
 }

backend/Core/Musify.Application/Configuration/TrackConfiguration.cs

@@ -1,116 +1,55 @@
 using System.ComponentModel.DataAnnotations;
 using Musify.Application.Shared;
 
-namespace Musify.Application.Configuration
+namespace Musify.Application.Configuration;
+
+public class TrackConfiguration : IConfigurationOptions, IPictureOwnerConfiguration
 {
-    public class TrackConfiguration
+    public static string SectionName => "Track";
+
+    [Required]
+    public TrackRoutes Routes { get; set; } = new();
+
+    [Required]
+    public PictureSizes PicturesSizes { get; set; } = new();
+
+    PictureRoutes IPictureOwnerConfiguration.Routes => Routes;
+}
+
+public class TrackRoutes : PictureRoutes
+{
+    public TrackRoutes()
     {
-        public const string SectionName = "Track";
-
-        [Required]
-        public TrackRoutes Routes { get; set; } = new TrackRoutes();
-
-        [Required]
-        public TrackPicturesSizes PicturesSizes { get; set; } = new TrackPicturesSizes();
+        ParentFolder = "Tracks";
     }
 
-    public class TrackRoutes
-    {
-        [Required]
-        public string UploadsFolder { get; set; } = "uploads";
+    [Required]
+    public string PresetOriginalPicture { get; set; } = "PresetOriginalPicture.webp";
 
-        [Required]
-        public string ParentFolder { get; set; } = "Tracks";
+    [Required]
+    public string PresetSmallPicture { get; set; } = "PresetSmallPicture.webp";
 
-        [Required]
-        public string OriginalPicturesFolder { get; set; } = "OriginalPictures";
+    [Required]
+    public string PresetMediumPicture { get; set; } = "PresetMediumPicture.webp";
 
-        [Required]
-        public string SmallPicturesFolder { get; set; } = "SmallPictures";
+    [Required]
+    public string PresetLargePicture { get; set; } = "PresetLargePicture.webp";
 
-        [Required]
-        public string MediumPicturesFolder { get; set; } = "MediumPictures";
+    [Required]
+    public string OriginalAudiosFolder { get; set; } = "OriginalAudios";
 
-        [Required]
-        public string LargePicturesFolder { get; set; } = "LargePictures";
+    [Required]
+    public string ProcessedAudiosFolder { get; set; } = "ProcessedAudios";
 
-        [Required]
-        public string PresetOriginalPicture { get; set; } = "PresetOriginalPicture.webp";
+    public string PresetSmallPicturePath => StorageKey.Combine(ParentFolder, PresetSmallPicture);
 
-        [Required]
-        public string PresetSmallPicture { get; set; } = "PresetSmallPicture.webp";
+    public string PresetMediumPicturePath => StorageKey.Combine(ParentFolder, PresetMediumPicture);
 
-        [Required]
-        public string PresetMediumPicture { get; set; } = "PresetMediumPicture.webp";
+    public string PresetLargePicturePath => StorageKey.Combine(ParentFolder, PresetLargePicture);
 
-        [Required]
-        public string PresetLargePicture { get; set; } = "PresetLargePicture.webp";
+    public string BuildOriginalAudioPath(long userId, string audioName) =>
+        StorageKey.Combine(UploadsFolder, userId.ToString(), ParentFolder, OriginalAudiosFolder, audioName);
 
-        [Required]
-        public string OriginalAudiosFolder { get; set; } = "OriginalAudios";
-
-        [Required]
-        public string ProcessedAudioFolder { get; set; } = "ProcessedAudios";
-
-        public string SmallPicturesPath => StorageKey.Combine(ParentFolder, SmallPicturesFolder);
-
-        public string MediumPicturesPath => StorageKey.Combine(ParentFolder, MediumPicturesFolder);
-
-        public string LargePicturesPath => StorageKey.Combine(ParentFolder, LargePicturesFolder);
-
-        public string PresetSmallPicturePath => StorageKey.Combine(ParentFolder, PresetSmallPicture);
-
-        public string PresetMediumPicturePath => StorageKey.Combine(ParentFolder, PresetMediumPicture);
-
-        public string PresetLargePicturePath => StorageKey.Combine(ParentFolder, PresetLargePicture);
-
-        public string OriginalPicturesPath => StorageKey.Combine(ParentFolder, OriginalPicturesFolder);
-
-        public string OriginalAudiosPath => StorageKey.Combine(ParentFolder, OriginalAudiosFolder);
-
-        public string ProcessedAudiosPath => StorageKey.Combine(ParentFolder, ProcessedAudioFolder);
-
-        public string BuildOriginalPicturePath(string pictureName) => StorageKey.Combine(OriginalPicturesPath, pictureName);
-
-        public string BuildOriginalPicturePath(long userId, string pictureName) => StorageKey.Combine(UploadsFolder, userId.ToString(), OriginalPicturesPath, pictureName);
-
-        public string BuildSmallPicturePath(string pictureName) => StorageKey.Combine(SmallPicturesPath, pictureName);
-
-        public string BuildMediumPicturePath(string pictureName) => StorageKey.Combine(MediumPicturesPath, pictureName);
-
-        public string BuildLargePicturePath(string pictureName) => StorageKey.Combine(LargePicturesPath, pictureName);
-
-        public string BuildOriginalAudioPath(string audioName) => StorageKey.Combine(OriginalAudiosPath, audioName);
-
-        public string BuildOriginalAudioPath(long userId, string audioName) => StorageKey.Combine(UploadsFolder, userId.ToString(), OriginalAudiosPath, audioName);
-
-        public string BuildProcessedAudioPath(string audioName) => StorageKey.Combine(ProcessedAudiosPath, audioName);
-
-        public string BuildTempPicturePath(string tempRootPrefix, long userId, string objectName) =>
-            StorageKey.Combine(tempRootPrefix, userId.ToString(), ParentFolder, objectName);
-
-        public string BuildTempAudioPath(string tempRootPrefix, long userId, string objectName) =>
-            StorageKey.Combine(tempRootPrefix, userId.ToString(), ParentFolder, objectName);
-    }
-
-    public class TrackPicturesSizes
-    {
-        [Range(1, 1024)]
-        public int SmallPictureWidth { get; set; } = 128;
-
-        [Range(1, 1024)]
-        public int SmallPictureHeight { get; set; } = 128;
-
-        [Range(1, 1024)]
-        public int MediumPictureWidth { get; set; } = 256;
-
-        [Range(1, 1024)]
-        public int MediumPictureHeight { get; set; } = 256;
-
-        [Range(1, 1024)]
-        public int LargePictureWidth { get; set; } = 512;
-
-        [Range(1, 1024)]
-        public int LargePictureHeight { get; set; } = 512;
-    }
-}
+    public string BuildProcessedAudioPath(string folderName) =>
+        StorageKey.Combine(ParentFolder, ProcessedAudiosFolder, folderName);
+}

backend/Core/Musify.Application/Configuration/UploadIntentConfiguration.cs

@@ -1,42 +1,41 @@
 using System.ComponentModel.DataAnnotations;
 
-namespace Musify.Application.Configuration
+namespace Musify.Application.Configuration;
+
+public class UploadIntentConfiguration : IConfigurationOptions
 {
-    public class UploadIntentConfiguration
-    {
-        public const string SectionName = "UploadIntent";
+    public static string SectionName => "UploadIntent";
 
-        [Range(10, 3600)]
-        public int UploadUrlExpiresInSeconds { get; set; } = 120;
+    [Range(10, 3600)]
+    public int UploadUrlExpiresInSeconds { get; set; } = 120;
 
-        [Range(1, 100)]
-        public int MaxActiveUploadIntentsPerUser { get; set; } = 5;
+    [Range(1, 100)]
+    public int MaxActiveUploadIntentsPerUser { get; set; } = 5;
 
-        [Range(1, long.MaxValue)]
-        public long MaxActiveUploadBytesPerUser { get; set; } = 200L * 1024 * 1024;
+    [Range(1, long.MaxValue)]
+    public long MaxActiveUploadBytesPerUser { get; set; } = 200L * 1024 * 1024;
 
-        [Range(1, long.MaxValue)]
-        public long MaxUploadBytes { get; set; } = 100L * 1024 * 1024;
+    [Range(1, long.MaxValue)]
+    public long MaxUploadBytes { get; set; } = 100L * 1024 * 1024;
 
-        [Range(1, long.MaxValue)]
-        public long DefaultExpectedPictureSizeBytes { get; set; } = 10L * 1024 * 1024;
+    [Range(1, long.MaxValue)]
+    public long DefaultExpectedPictureSizeBytes { get; set; } = 10L * 1024 * 1024;
 
-        [Range(1, long.MaxValue)]
-        public long DefaultExpectedAudioSizeBytes { get; set; } = 100L * 1024 * 1024;
+    [Range(1, long.MaxValue)]
+    public long DefaultExpectedAudioSizeBytes { get; set; } = 100L * 1024 * 1024;
 
-        [Range(30, 86400)]
-        public int ExpirationJobIntervalSeconds { get; set; } = 300;
+    [Range(30, 86400)]
+    public int ExpirationJobIntervalSeconds { get; set; } = 300;
 
-        [Range(0, 365)]
-        public int ExpiredIntentsRetentionDays { get; set; } = 7;
+    [Range(0, 365)]
+    public int ExpiredIntentsRetentionDays { get; set; } = 7;
 
-        [Required, MinLength(1)]
-        public string TemporalRootPrefix { get; set; } = "temporal";
+    [Required, MinLength(1)]
+    public string TempRootPrefix { get; set; } = "temp";
 
-        [Range(1, 30)]
-        public int TemporalUploadsRetentionDays { get; set; } = 3;
+    [Range(1, 30)]
+    public int TempUploadsRetentionDays { get; set; } = 3;
 
-        [Range(60, 86400)]
-        public int TemporalCleanUpJobIntervalSeconds { get; set; } = 3600;
-    }
+    [Range(60, 86400)]
+    public int TempCleanupJobIntervalSeconds { get; set; } = 3600;
 }

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

@@ -1,4 +1,3 @@
-namespace Musify.Application.Contracts
-{
-    public record AudioTranscodeResult(int StatusCode, TimeSpan Duration);
-}
+namespace Musify.Application.Contracts;
+
+public record AudioTranscodeResult(int StatusCode, TimeSpan Duration);

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

@@ -1,9 +1,6 @@
-namespace Musify.Application.Contracts
-{
-    public interface IAudioTranscoderService
-    {
-        Task<AudioTranscodeResult> TranscodeToAudioFileAsync(Stream audioStream, string destinationPath, CancellationToken cancellationToken);
+namespace Musify.Application.Contracts;
 
-        Task<bool> IsValidAudioFileAsync(string filePath, CancellationToken cancellationToken);
-    }
-}
+public interface IAudioTranscoderService
+{
+    public Task<AudioTranscodeResult> TranscodeToAudioFileAsync(Stream audioStream, string destinationPath, CancellationToken cancellationToken);
+}

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

@@ -1,42 +1,40 @@
+using ErrorOr;
 using Microsoft.EntityFrameworkCore;
 using Musify.Domain.Entities;
 
-namespace Musify.Application.Contracts
+namespace Musify.Application.Contracts;
+
+public interface IDatabase
 {
-    public interface IDatabase
-    {
-        DbSet<User> Users { get; }
+    public DbSet<User> Users { get; }
 
-        DbSet<PlayList> PlayLists { get; }
+    public DbSet<PlayList> PlayLists { get; }
 
-        DbSet<Album> Albums { get; }
+    public DbSet<Album> Albums { get; }
 
-        DbSet<AlbumHasTrack> AlbumHasTracks { get; }
+    public DbSet<AlbumHasTrack> AlbumHasTracks { get; }
 
-        DbSet<Track> Tracks { get; }
+    public DbSet<Track> Tracks { get; }
 
-        DbSet<UserHasTrack> UserHasTracks { get; }
+    public DbSet<PlayListHasTrack> PlayListHasTracks { get; }
 
-        DbSet<PlayListHasTrack> PlayListHasTracks { get; }
+    public DbSet<Mix> Mixes { get; }
 
-        DbSet<Mix> Mixes { get; }
+    public DbSet<MixItem> MixItems { get; }
 
-        DbSet<MixItem> MixItems { get; }
+    public DbSet<UploadIntent> UploadIntents { get; }
 
-        DbSet<Upload> Uploads { get; }
+    public DbSet<ListeningHistory> ListeningHistories { get; }
 
-        DbSet<UploadIntent> UploadIntents { get; }
+    public DbSet<TrackLike> TrackLikes { get; }
 
-        DbSet<ListeningHistory> ListeningHistories { get; }
+    public DbSet<TrackTag> TrackTags { get; }
 
-        DbSet<TrackLike> TrackLikes { get; }
+    public DbSet<UserFollow> UserFollows { get; }
 
-        DbSet<TrackTag> TrackTags { get; }
+    public Task<IDatabaseTransaction> BeginTransactionAsync(System.Data.IsolationLevel isolationLevel, CancellationToken cancellationToken);
 
-        DbSet<UserFollow> UserFollows { get; }
+    public Task<int> SaveChangesAsync(CancellationToken cancellationToken);
 
-        Task<IDatabaseTransaction> BeginTransactionAsync(System.Data.IsolationLevel isolationLevel, CancellationToken cancellationToken);
-
-        Task<int> SaveChangesAsync(CancellationToken cancellationToken);
-    }
-}
+    public Task<ErrorOr<Success>> TrySaveChangesAsync(Error onUniqueViolation, CancellationToken cancellationToken);
+}

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

@@ -1,7 +1,6 @@
-namespace Musify.Application.Contracts
+namespace Musify.Application.Contracts;
+
+public interface IDatabaseTransaction : IAsyncDisposable
 {
-    public interface IDatabaseTransaction : IAsyncDisposable
-    {
-        Task CommitAsync(CancellationToken cancellationToken = default);
-    }
+    public Task CommitAsync(CancellationToken cancellationToken = default);
 }

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

@@ -1,7 +1,6 @@
-namespace Musify.Application.Contracts
+namespace Musify.Application.Contracts;
+
+public interface IEventBus
 {
-    public interface IEventBus
-    {
-        Task PublishAsync<T>(T message, CancellationToken cancellationToken) where T : class;
-    }
-}
+    public Task PublishAsync<T>(T message, CancellationToken cancellationToken) where T : class;
+}

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

@@ -1,7 +1,6 @@
-namespace Musify.Application.Contracts
+namespace Musify.Application.Contracts;
+
+public interface IPictureService
 {
-    public interface IPictureService
-    {
-        Task<Stream> ResizePictureAsWebpAsync(Stream pictureStream, int width, int height, CancellationToken cancellationToken);
-    }
-}
+    public Task<Stream> ResizePictureAsWebpAsync(Stream pictureStream, int width, int height, CancellationToken cancellationToken);
+}

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

@@ -1,28 +1,24 @@
-namespace Musify.Application.Contracts
+namespace Musify.Application.Contracts;
+
+public interface IStorageService
 {
-    public interface IStorageService
-    {
-        Task<Stream> GetFileAsync(string bucket, string key, CancellationToken cancellationToken);
+    /// <summary>Opens an object for reading, or returns null when it does not exist.</summary>
+    public Task<Stream?> GetFileAsync(string bucket, string key, CancellationToken cancellationToken);
 
-        Task<ObjectMetaData?> HeadObjectAsync(string bucket, string key, CancellationToken cancellationToken);
+    public Task<ObjectMetaData?> HeadObjectAsync(string bucket, string key, CancellationToken cancellationToken);
 
-        Task<string> GetUrlAsync(string bucket, string key, TimeSpan ExpirationTime, CancellationToken cancellationToken);
+    public Task<string> GetUploadUrlAsync(string bucket, string key, string contentType, TimeSpan expirationTime, bool preventOverwrite = true, CancellationToken cancellationToken = default);
 
-        Task<string> GetUploadUrlAsync(string bucket, string key, string contentType, TimeSpan expirationTime, CancellationToken cancellationToken, bool preventOverwrite = true);
+    public Task UploadFileAsync(string filePath, string bucket, string key, CancellationToken cancellationToken);
 
-        Task UploadFileAsync(string filePath, string bucket, string key, CancellationToken cancellationToken);
+    public Task UploadFileAsync(Stream sourceStream, string contentType, string bucket, string key, CancellationToken cancellationToken);
 
-        Task UploadFileAsync(Stream sourceStream, string contentType, string bucket, string key, CancellationToken cancellationToken);
+    public Task<IReadOnlyList<string>> TransferFilesAsync(string sourceDirectory, string bucket, string route, CancellationToken cancellationToken);
 
-        Task<IReadOnlyList<string>> TransferFilesAsync(string sourceDirectory, string bucket, string route, CancellationToken cancellationToken);
+    public Task RemoveFileAsync(string bucket, string key, CancellationToken cancellationToken);
 
-        Task RemoveFileAsync(string bucket, string key, CancellationToken cancellationToken);
+    public Task CopyFileAsync(string sourceBucket, string sourceKey, string destinationBucket, string destinationKey,
+        CancellationToken cancellationToken);
 
-        Task CopyFileAsync(string sourceBucket, string sourceKey, string destinationBucket, string destinationKey,
-            CancellationToken cancellationToken);
-
-        Task RemoveFolderAsync(string bucket, string folderKey, CancellationToken cancellationToken);
-        
-        IAsyncEnumerable<StorageObject> ListObjectsAsync(string bucket, string prefix, CancellationToken cancellationToken);
-    }
-}
+    public IAsyncEnumerable<StorageObject> ListObjectsAsync(string bucket, string prefix, CancellationToken cancellationToken);
+}

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

@@ -1,10 +1,8 @@
-namespace Musify.Application.Contracts
+namespace Musify.Application.Contracts;
+
+public interface IStreamTicketService
 {
-    public interface IStreamTicketService
-    {
-
-        StreamTicket IssueTicket(long? userId, string keyPrefix, long? maxBytes = null);
-    }
-
-    public record StreamTicket(string Token, int ExpiresInSeconds);
+    public StreamTicket IssueTicket(long? userId, string keyPrefix, long? maxBytes = null);
 }
+
+public record StreamTicket(string Token, int ExpiresInSeconds);

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

@@ -1,4 +1,3 @@
-namespace Musify.Application.Contracts
-{
-    public record ObjectMetaData(string ContentType, long ContentLength);
-}
+namespace Musify.Application.Contracts;
+
+public record ObjectMetaData(string ContentType, long ContentLength);

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

@@ -1,4 +1,3 @@
-namespace Musify.Application.Contracts
-{
-    public record StorageObject(string Key, DateTime LastModifiedUtc);
-}
+namespace Musify.Application.Contracts;
+
+public record StorageObject(string Key, DateTime LastModifiedUtc);

backend/Core/Musify.Application/Events/AlbumPictureProcessed.cs

@@ -1,4 +1,3 @@
-namespace Musify.Application.Events
-{
-    public record AlbumPictureProcessed(Guid AlbumId);
-}
+namespace Musify.Application.Events;
+
+public record AlbumPictureProcessed(Guid AlbumId);

backend/Core/Musify.Application/Events/AlbumPictureProcessingFailed.cs

@@ -1,4 +1,3 @@
-namespace Musify.Application.Events
-{
-    public record AlbumPictureProcessingFailed(Guid AlbumId);
-}
+namespace Musify.Application.Events;
+
+public record AlbumPictureProcessingFailed(Guid AlbumId);

backend/Core/Musify.Application/Events/AlbumProcessingFailed.cs

@@ -1,7 +1,6 @@
-namespace Musify.Application.Events
-{
-    public record AlbumProcessingFailed(
-        Guid AlbumId,
-        string? Bucket,
-        string? PictureKey);
-}
+namespace Musify.Application.Events;
+
+public record AlbumProcessingFailed(
+    Guid AlbumId,
+    string? Bucket,
+    string? PictureKey);

backend/Core/Musify.Application/Events/CreateAlbumResourcesEvent.cs

@@ -1,14 +1,11 @@
 using Musify.Application.Shared;
 
-namespace Musify.Application.Events
-{
-    public record CreateAlbumResourcesEvent(
-        Guid AlbumId,
-        Guid PictureIntentId,
-        string Bucket,
-        string PictureSourceKey,
-        string PictureDestinationKey,
-        ImageSize Small,
-        ImageSize Medium,
-        ImageSize Large);
-}
+namespace Musify.Application.Events;
+
+public record CreateAlbumResourcesEvent(
+    Guid AlbumId,
+    Guid PictureIntentId,
+    string Bucket,
+    string PictureSourceKey,
+    string PictureDestinationKey,
+    ImageSizes Sizes);

backend/Core/Musify.Application/Events/CreatePlayListResourcesEvent.cs

@@ -1,14 +1,11 @@
 using Musify.Application.Shared;
 
-namespace Musify.Application.Events
-{
-    public record CreatePlayListResourcesEvent(
-        Guid PlayListId,
-        Guid PictureIntentId,
-        string Bucket,
-        string PictureSourceKey,
-        string PictureDestinationKey,
-        ImageSize Small,
-        ImageSize Medium,
-        ImageSize Large);
-}
+namespace Musify.Application.Events;
+
+public record CreatePlayListResourcesEvent(
+    Guid PlayListId,
+    Guid PictureIntentId,
+    string Bucket,
+    string PictureSourceKey,
+    string PictureDestinationKey,
+    ImageSizes Sizes);

backend/Core/Musify.Application/Events/CreateTrackResourcesEvent.cs

@@ -1,18 +1,15 @@
 using Musify.Application.Shared;
 
-namespace Musify.Application.Events
-{
-    public record CreateTrackResourcesEvent(
-        Guid TrackId,
-        Guid PictureIntentId,
-        Guid AudioIntentId,
-        string Bucket,
-        string PictureSourceKey,
-        string PictureDestinationKey,
-        string AudioSourceKey,
-        string AudioDestinationKey,
-        string AudioProcessedFolderKey,
-        ImageSize Small,
-        ImageSize Medium,
-        ImageSize Large);
-}
+namespace Musify.Application.Events;
+
+public record CreateTrackResourcesEvent(
+    Guid TrackId,
+    Guid PictureIntentId,
+    Guid AudioIntentId,
+    string Bucket,
+    string PictureSourceKey,
+    string PictureDestinationKey,
+    string AudioSourceKey,
+    string AudioDestinationKey,
+    string AudioProcessedFolderKey,
+    ImageSizes Sizes);

backend/Core/Musify.Application/Events/DeleteAlbumEvent.cs

@@ -0,0 +1,5 @@
+namespace Musify.Application.Events;
+
+public record DeleteAlbumEvent(
+    Guid AlbumId,
+    long UserId);

backend/Core/Musify.Application/Events/DeletePlayListEvent.cs

@@ -1,6 +1,5 @@
-namespace Musify.Application.Events
-{
-    public record DeletePlayListEvent(
-        Guid PlayListId,
-        long UserId);
-}
+namespace Musify.Application.Events;
+
+public record DeletePlayListEvent(
+    Guid PlayListId,
+    long UserId);

backend/Core/Musify.Application/Events/DeleteTrackEvent.cs

@@ -1,6 +1,5 @@
-namespace Musify.Application.Events
-{
-    public record DeleteTrackEvent(
-        Guid TrackId,
-        long UserId);
-}
+namespace Musify.Application.Events;
+
+public record DeleteTrackEvent(
+    Guid TrackId,
+    long UserId);

backend/Core/Musify.Application/Events/PlayListPictureProcessed.cs

@@ -1,4 +1,3 @@
-namespace Musify.Application.Events
-{
-    public record PlayListPictureProcessed(Guid PlayListId);
-}
+namespace Musify.Application.Events;
+
+public record PlayListPictureProcessed(Guid PlayListId);

backend/Core/Musify.Application/Events/PlayListPictureProcessingFailed.cs

@@ -1,4 +1,3 @@
-namespace Musify.Application.Events
-{
-    public record PlayListPictureProcessingFailed(Guid PlayListId);
-}
+namespace Musify.Application.Events;
+
+public record PlayListPictureProcessingFailed(Guid PlayListId);

backend/Core/Musify.Application/Events/PlayListProcessingFailed.cs

@@ -1,7 +1,6 @@
-namespace Musify.Application.Events
-{
-    public record PlayListProcessingFailed(
-        Guid PlayListId,
-        string? Bucket,
-        string? PictureKey);
-}
+namespace Musify.Application.Events;
+
+public record PlayListProcessingFailed(
+    Guid PlayListId,
+    string? Bucket,
+    string? PictureKey);

backend/Core/Musify.Application/Events/TrackAudioProcessed.cs

@@ -1,4 +1,3 @@
-namespace Musify.Application.Events
-{
-    public record TrackAudioProcessed(Guid TrackId);
-}
+namespace Musify.Application.Events;
+
+public record TrackAudioProcessed(Guid TrackId);

backend/Core/Musify.Application/Events/TrackAudioProcessingFailed.cs

@@ -1,4 +1,3 @@
-namespace Musify.Application.Events
-{
-    public record TrackAudioProcessingFailed(Guid TrackId);
-}
+namespace Musify.Application.Events;
+
+public record TrackAudioProcessingFailed(Guid TrackId);

backend/Core/Musify.Application/Events/TrackPictureProcessed.cs

@@ -1,4 +1,3 @@
-namespace Musify.Application.Events
-{
-    public record TrackPictureProcessed(Guid TrackId);
-}
+namespace Musify.Application.Events;
+
+public record TrackPictureProcessed(Guid TrackId);

backend/Core/Musify.Application/Events/TrackPictureProcessingFailed.cs

@@ -1,4 +1,3 @@
-namespace Musify.Application.Events
-{
-    public record TrackPictureProcessingFailed(Guid TrackId);
-}
+namespace Musify.Application.Events;
+
+public record TrackPictureProcessingFailed(Guid TrackId);

backend/Core/Musify.Application/Events/TrackProcessingFailed.cs

@@ -1,8 +1,7 @@
-namespace Musify.Application.Events
-{
-    public record TrackProcessingFailed(
-        Guid TrackId,
-        string? Bucket,
-        string? PictureKey,
-        string? AudioKey);
-}
+namespace Musify.Application.Events;
+
+public record TrackProcessingFailed(
+    Guid TrackId,
+    string? Bucket,
+    string? PictureKey,
+    string? AudioKey);

backend/Core/Musify.Application/Events/UpdateAlbumPictureEvent.cs

@@ -1,12 +1,9 @@
 using Musify.Application.Shared;
 
-namespace Musify.Application.Events
-{
-    public record UpdateAlbumPictureEvent(
-        Guid AlbumId,
-        string Bucket,
-        string SourceKey,
-        ImageSize Small,
-        ImageSize Medium,
-        ImageSize Large);
-}
+namespace Musify.Application.Events;
+
+public record UpdateAlbumPictureEvent(
+    Guid AlbumId,
+    string Bucket,
+    string SourceKey,
+    ImageSizes Sizes);

backend/Core/Musify.Application/Events/UpdateAlbumPictureSourceEvent.cs

@@ -1,14 +1,11 @@
 using Musify.Application.Shared;
 
-namespace Musify.Application.Events
-{
-    public record UpdateAlbumPictureSourceEvent(
-        Guid AlbumId,
-        Guid PictureIntentId,
-        string Bucket,
-        string PictureSourceKey,
-        string PictureDestinationKey,
-        ImageSize Small,
-        ImageSize Medium,
-        ImageSize Large);
-}
+namespace Musify.Application.Events;
+
+public record UpdateAlbumPictureSourceEvent(
+    Guid AlbumId,
+    Guid PictureIntentId,
+    string Bucket,
+    string PictureSourceKey,
+    string PictureDestinationKey,
+    ImageSizes Sizes);

backend/Core/Musify.Application/Events/UpdatePlayListPictureEvent.cs

@@ -1,12 +1,9 @@
 using Musify.Application.Shared;
 
-namespace Musify.Application.Events
-{
-    public record UpdatePlayListPictureEvent(
-        Guid PlayListId,
-        string Bucket,
-        string SourceKey,
-        ImageSize Small,
-        ImageSize Medium,
-        ImageSize Large);
-}
+namespace Musify.Application.Events;
+
+public record UpdatePlayListPictureEvent(
+    Guid PlayListId,
+    string Bucket,
+    string SourceKey,
+    ImageSizes Sizes);

backend/Core/Musify.Application/Events/UpdatePlayListPictureSourceEvent.cs

@@ -1,14 +1,11 @@
 using Musify.Application.Shared;
 
-namespace Musify.Application.Events
-{
-    public record UpdatePlayListPictureSourceEvent(
-        Guid PlayListId,
-        Guid PictureIntentId,
-        string Bucket,
-        string PictureSourceKey,
-        string PictureDestinationKey,
-        ImageSize Small,
-        ImageSize Medium,
-        ImageSize Large);
-}
+namespace Musify.Application.Events;
+
+public record UpdatePlayListPictureSourceEvent(
+    Guid PlayListId,
+    Guid PictureIntentId,
+    string Bucket,
+    string PictureSourceKey,
+    string PictureDestinationKey,
+    ImageSizes Sizes);

backend/Core/Musify.Application/Events/UpdateTrackAudioEvent.cs

@@ -1,9 +1,8 @@
-namespace Musify.Application.Events
-{
-    public record UpdateTrackAudioEvent(
-        Guid TrackId,
-        string SourceBucket,
-        string SourceKey,
-        string DestinationBucket,
-        string DestinationFolderKey);
-}
+namespace Musify.Application.Events;
+
+public record UpdateTrackAudioEvent(
+    Guid TrackId,
+    string SourceBucket,
+    string SourceKey,
+    string DestinationBucket,
+    string DestinationFolderKey);

backend/Core/Musify.Application/Events/UpdateTrackPictureEvent.cs

@@ -1,12 +1,9 @@
 using Musify.Application.Shared;
 
-namespace Musify.Application.Events
-{
-    public record UpdateTrackPictureEvent(
-        Guid TrackId,
-        string Bucket,
-        string SourceKey,
-        ImageSize Small,
-        ImageSize Medium,
-        ImageSize Large);
-}
+namespace Musify.Application.Events;
+
+public record UpdateTrackPictureEvent(
+    Guid TrackId,
+    string Bucket,
+    string SourceKey,
+    ImageSizes Sizes);

backend/Core/Musify.Application/Genres/GetAvailableGenres.cs

@@ -0,0 +1,24 @@
+using Mediator;
+using Musify.Domain.ValueObjects;
+using Musify.Application.Genres.Responses;
+
+namespace Musify.Application.Genres;
+
+public record GetAvailableGenresQuery : IQuery<IReadOnlyList<AvailableGenreResponse>>;
+
+public class GetAvailableGenresQueryHandler
+    : IQueryHandler<GetAvailableGenresQuery, IReadOnlyList<AvailableGenreResponse>>
+{
+    public ValueTask<IReadOnlyList<AvailableGenreResponse>> Handle(GetAvailableGenresQuery request, CancellationToken cancellationToken)
+    {
+        var all = Enum.GetValues<Genre>();
+
+        IReadOnlyList<AvailableGenreResponse> result = all
+            .Select(genre => new AvailableGenreResponse(
+                genre,
+                all.Where(other => !GenreCompatibility.AreCompatible(genre, other)).ToList()))
+            .ToList();
+
+        return ValueTask.FromResult(result);
+    }
+}

backend/Core/Musify.Application/Genres/GetGenres.cs

@@ -0,0 +1,29 @@
+using Mediator;
+using Microsoft.EntityFrameworkCore;
+using Musify.Application.Contracts;
+using Musify.Domain.ValueObjects;
+using Musify.Application.Genres.Responses;
+
+namespace Musify.Application.Genres;
+
+public record GetGenresQuery : IQuery<IReadOnlyList<GenreResponse>>;
+
+public class GetGenresQueryHandler(IDatabase database)
+    : IQueryHandler<GetGenresQuery, IReadOnlyList<GenreResponse>>
+{
+    public async ValueTask<IReadOnlyList<GenreResponse>> Handle(GetGenresQuery request, CancellationToken cancellationToken)
+    {
+        var rows = await database.TrackTags
+            .AsNoTracking()
+            .Where(tag => tag.Track.LifeCycleStatus == LifeCycleStatus.Active)
+            .GroupBy(tag => tag.Tag)
+            .Select(group => new { Genre = group.Key, TrackCount = group.Select(tag => tag.TrackId).Distinct().Count() })
+            .ToListAsync(cancellationToken);
+
+        return rows
+            .OrderByDescending(row => row.TrackCount)
+            .ThenBy(row => row.Genre)
+            .Select(row => new GenreResponse(row.Genre, row.TrackCount))
+            .ToList();
+    }
+}

backend/Core/Musify.Application/Genres/Responses/AvailableGenreResponse.cs

@@ -0,0 +1,5 @@
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.Genres.Responses;
+
+public record AvailableGenreResponse(Genre Genre, IReadOnlyList<Genre> IncompatibleWith);

backend/Core/Musify.Application/Genres/Responses/GenreResponse.cs

@@ -0,0 +1,5 @@
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.Genres.Responses;
+
+public record GenreResponse(Genre Genre, int TrackCount);

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

@@ -1,43 +1,30 @@
-using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Musify.Application.Contracts;
 using Musify.Application.Shared;
 using Musify.Application.Tracks.Responses;
-using X.PagedList;
-using X.PagedList.EF;
+using Musify.Domain.ValueObjects;
 
-namespace Musify.Application.Likes
+namespace Musify.Application.Likes;
+
+public record GetLikedTracksQuery(
+    long UserId,
+    int PageNumber,
+    int PageSize)
+    : IQuery<PaginatedResponse<TrackApplicationResponse>>;
+
+public class GetLikedTracksQueryHandler(IDatabase database)
+    : IQueryHandler<GetLikedTracksQuery, PaginatedResponse<TrackApplicationResponse>>
 {
-    public record GetLikedTracksQuery(
-        long UserId,
-        int PageNumber,
-        int PageSize)
-        : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse>>>;
-
-    public class GetLikedTracksQueryHandler(IDatabase database)
-        : IQueryHandler<GetLikedTracksQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>>>
+    public async ValueTask<PaginatedResponse<TrackApplicationResponse>> Handle(GetLikedTracksQuery request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<PaginatedResponse<TrackApplicationResponse>>> Handle(GetLikedTracksQuery request, CancellationToken cancellationToken)
-        {
-            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);
-
-            var pagedEntities = await likesQuery
-                .OrderByDescending(like => like.CreatedAt)
-                .Select(like => new { like.Track, ListensCount = like.Track.ListeningHistories.Count(l => l.IsCounted) })
-                .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
-
-            var pagedTracks = new StaticPagedList<TrackApplicationResponse>(
-                pagedEntities.Select(x => TrackApplicationResponse.FromEntity(x.Track, x.ListensCount)),
-                pagedEntities.PageNumber, pagedEntities.PageSize, pagedEntities.TotalItemCount);
-
-            return PaginatedResponse<TrackApplicationResponse>.FromPagedList(pagedTracks);
-        }
+        return await database.TrackLikes
+            .AsNoTracking()
+            .Where(like => like.UserId == request.UserId && like.Track.LifeCycleStatus == LifeCycleStatus.Active)
+            .OrderByDescending(like => like.CreatedAt)
+            .ThenBy(like => like.Id)
+            .Select(like => like.Track)
+            .SelectResponse()
+            .ToPaginatedAsync(new PageRequest(request.PageNumber, request.PageSize), cancellationToken);
     }
 }

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

@@ -3,54 +3,56 @@ using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
 using Musify.Application.Contracts;
+using Musify.Application.Shared;
 using Musify.Domain.Entities;
+using Musify.Domain.ValueObjects;
 
-namespace Musify.Application.Likes
+namespace Musify.Application.Likes;
+
+public record ToggleTrackLikeCommand(long UserId, Guid TrackId)
+    : ICommand<ErrorOr<bool>>;
+
+public class ToggleTrackLikeCommandHandler(
+    IDatabase database,
+    ILogger<ToggleTrackLikeCommandHandler> logger)
+    : ICommandHandler<ToggleTrackLikeCommand, ErrorOr<bool>>
 {
-    public record ToggleTrackLikeCommand(long UserId, Guid TrackId)
-        : ICommand<ErrorOr<bool>>;
-
-    public class ToggleTrackLikeCommandHandler(
-        IDatabase database,
-        ILogger<ToggleTrackLikeCommandHandler> logger)
-        : ICommandHandler<ToggleTrackLikeCommand, ErrorOr<bool>>
+    public async ValueTask<ErrorOr<bool>> Handle(ToggleTrackLikeCommand request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<bool>> Handle(ToggleTrackLikeCommand request, CancellationToken cancellationToken)
+        var trackExists = await database.Tracks
+            .AsNoTracking()
+            .AnyAsync(t => t.Id == request.TrackId && t.LifeCycleStatus == LifeCycleStatus.Active, cancellationToken);
+        if (!trackExists)
+            return AppErrors.NotFound("Track", request.TrackId);
+
+        var existingLike = await database.TrackLikes
+            .SingleOrDefaultAsync(like => like.UserId == request.UserId && like.TrackId == request.TrackId, cancellationToken);
+
+        bool nowLiked;
+        if (existingLike != null)
         {
-            var trackExists = await database.Tracks
-                .AsNoTracking()
-                .AnyAsync(t => t.Id == request.TrackId, cancellationToken);
-            if (!trackExists)
-            {
-                logger.LogInformation("Track {TrackId} not found", request.TrackId);
-                return Error.NotFound(description: $"Track {request.TrackId} not found");
-            }
-
-            var existingLike = await database.TrackLikes
-                .SingleOrDefaultAsync(like => like.UserId == request.UserId && like.TrackId == request.TrackId, cancellationToken);
-
-            bool nowLiked;
-            if (existingLike != null)
-            {
-                database.TrackLikes.Remove(existingLike);
-                nowLiked = false;
-            }
-            else
-            {
-                await database.TrackLikes.AddAsync(new TrackLike
-                {
-                    UserId = request.UserId,
-                    TrackId = request.TrackId
-                }, cancellationToken);
-                nowLiked = true;
-            }
-
-            await database.SaveChangesAsync(cancellationToken);
-
-            logger.LogInformation("User {UserId} {Action} track {TrackId}",
-                request.UserId, nowLiked ? "liked" : "unliked", request.TrackId);
-
-            return nowLiked;
+            database.TrackLikes.Remove(existingLike);
+            nowLiked = false;
         }
+        else
+        {
+            await database.TrackLikes.AddAsync(new TrackLike
+            {
+                UserId = request.UserId,
+                TrackId = request.TrackId
+            }, cancellationToken);
+            nowLiked = true;
+        }
+
+        // A concurrent double click can hit the unique index; the outcome is already in place, so treat it as a no-op.
+        var saved = await database.TrySaveChangesAsync(
+            AppErrors.Conflict("TrackLike.Duplicate", "Track is already liked."), cancellationToken);
+        if (saved.IsError)
+            return true;
+
+        logger.LogInformation("User {UserId} {Action} track {TrackId}",
+            request.UserId, nowLiked ? "liked" : "unliked", request.TrackId);
+
+        return nowLiked;
     }
 }

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

@@ -1,4 +1,3 @@
-using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
@@ -7,146 +6,124 @@ using Musify.Application.Contracts;
 using Musify.Domain.Entities;
 using Musify.Domain.ValueObjects;
 
-namespace Musify.Application.Mixes
+namespace Musify.Application.Mixes;
+
+public record GenerateMixesForUserCommand(long UserId)
+    : ICommand;
+
+public class GenerateMixesForUserCommandHandler(
+    IDatabase database,
+    MixConfiguration mixConfiguration,
+    ILogger<GenerateMixesForUserCommandHandler> logger)
+    : ICommandHandler<GenerateMixesForUserCommand>
 {
-    public record GenerateMixesForUserCommand(long UserId)
-        : ICommand<ErrorOr<Success>>;
+    private sealed record MixDraft(MixKind Kind, IReadOnlyList<Guid> TrackIds);
 
-    public class GenerateMixesForUserCommandHandler(
-        IDatabase database,
-        MixConfiguration mixConfiguration,
-        ILogger<GenerateMixesForUserCommandHandler> logger)
-        : ICommandHandler<GenerateMixesForUserCommand, ErrorOr<Success>>
+    public async ValueTask<Unit> Handle(GenerateMixesForUserCommand request, CancellationToken cancellationToken)
     {
-        private sealed record MixDraft(string Title, string? Subtitle, IReadOnlyList<Guid> TrackIds);
+        var userId = request.UserId;
 
-        public async ValueTask<ErrorOr<Success>> Handle(GenerateMixesForUserCommand request, CancellationToken cancellationToken)
+        var libraryTrackIds = await database.Tracks
+            .AsNoTracking()
+            .Where(track => track.OwnerUserId == userId && track.LifeCycleStatus == LifeCycleStatus.Active)
+            .Select(track => track.Id)
+            .ToListAsync(cancellationToken);
+
+        if (libraryTrackIds.Count == 0)
         {
-            var userId = request.UserId;
-
-            var libraryTrackIds = await database.UserHasTracks
-                .AsNoTracking()
-                .Where(userTrack => userTrack.UserId == userId && userTrack.Track.LifeCycleStatus == LifeCycleStatus.Active)
-                .Select(userTrack => userTrack.TrackId)
-                .ToListAsync(cancellationToken);
-
-            if (libraryTrackIds.Count == 0)
-            {
-                logger.LogInformation("User {UserId} has no tracks yet, skipping mix generation", userId);
-                return new Success();
-            }
-
-            var historyTrackIds = await database.ListeningHistories
-                .AsNoTracking()
-                .Where(history => history.UserId == userId && history.IsCounted)
-                .Select(history => history.TrackId)
-                .Distinct()
-                .ToListAsync(cancellationToken);
-
-            var historySet = new HashSet<Guid>(historyTrackIds);
-            var unheardTrackIds = libraryTrackIds.Where(id => !historySet.Contains(id)).ToList();
-
-            var drafts = new List<MixDraft>();
-
-            var discovery = Take(Shuffle(unheardTrackIds));
-            if (discovery.Count > 0)
-            {
-                drafts.Add(new MixDraft(
-                    "Descubrimiento",
-                    "Canciones de tu biblioteca que todavía no has escuchado.",
-                    discovery));
-            }
-
-            var daily = Take(Interleave(Shuffle(historyTrackIds), Shuffle(unheardTrackIds)));
-            if (daily.Count > 0)
-            {
-                drafts.Add(new MixDraft(
-                    "Tu mezcla diaria",
-                    "Lo que más escuchas, con alguna sorpresa de tu biblioteca.",
-                    daily));
-            }
-
-            if (drafts.Count == 0)
-            {
-                logger.LogInformation("No candidate songs found for user {UserId}, skipping mix generation", userId);
-                return new Success();
-            }
-
-            await ReplaceMixesAsync(userId, drafts, cancellationToken);
-
-            try
-            {
-                await database.SaveChangesAsync(cancellationToken);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to generate mixes for user {UserId}", userId);
-                return Error.Failure(description: $"Failed to generate mixes for user {userId}");
-            }
-
-            logger.LogInformation("Generated {Count} mixes for user {UserId}", drafts.Count, userId);
-            return new Success();
+            logger.LogInformation("User {UserId} has no tracks yet, skipping mix generation", userId);
+            return Unit.Value;
         }
 
-        private List<Guid> Take(IEnumerable<Guid> trackIds) =>
-            [.. trackIds.Take(mixConfiguration.ItemsPerMix)];
+        var historyTrackIds = await database.ListeningHistories
+            .AsNoTracking()
+            .Where(history => history.UserId == userId && history.IsCounted)
+            .Select(history => history.TrackId)
+            .Distinct()
+            .ToListAsync(cancellationToken);
 
-        private static List<Guid> Shuffle(IEnumerable<Guid> trackIds) =>
-            [.. trackIds.OrderBy(_ => Guid.NewGuid())];
+        var historySet = new HashSet<Guid>(historyTrackIds);
+        var unheardTrackIds = libraryTrackIds.Where(id => !historySet.Contains(id)).ToList();
 
-        private static List<Guid> Interleave(IReadOnlyList<Guid> first, IReadOnlyList<Guid> second)
+        var drafts = new List<MixDraft>();
+
+        var discovery = Take(Shuffle(unheardTrackIds));
+        if (discovery.Count > 0)
         {
-            var merged = new List<Guid>(first.Count + second.Count);
-            for (var index = 0; index < Math.Max(first.Count, second.Count); index++)
-            {
-                if (index < first.Count)
-                    merged.Add(first[index]);
-                if (index < second.Count)
-                    merged.Add(second[index]);
-            }
-
-            return merged;
+            drafts.Add(new MixDraft(MixKind.Discovery, discovery));
         }
 
-        private async Task ReplaceMixesAsync(long userId, IReadOnlyList<MixDraft> drafts, CancellationToken cancellationToken)
+        var daily = Take(Interleave(Shuffle(historyTrackIds), Shuffle(unheardTrackIds)));
+        if (daily.Count > 0)
         {
-            var previousMixes = await database.Mixes
-                .Where(mix => mix.UserId == userId)
-                .ToListAsync(cancellationToken);
+            drafts.Add(new MixDraft(MixKind.Daily, daily));
+        }
 
-            if (previousMixes.Count > 0)
+        if (drafts.Count == 0)
+        {
+            logger.LogInformation("No candidate songs found for user {UserId}, skipping mix generation", userId);
+            return Unit.Value;
+        }
+
+        await ReplaceMixesAsync(userId, drafts, cancellationToken);
+
+        await database.SaveChangesAsync(cancellationToken);
+
+        logger.LogInformation("Generated {Count} mixes for user {UserId}", drafts.Count, userId);
+        return Unit.Value;
+    }
+
+    private List<Guid> Take(IEnumerable<Guid> trackIds) =>
+        [.. trackIds.Take(mixConfiguration.ItemsPerMix)];
+
+    private static List<Guid> Shuffle(IEnumerable<Guid> trackIds) =>
+        [.. trackIds.OrderBy(_ => Guid.NewGuid())];
+
+    private static List<Guid> Interleave(IReadOnlyList<Guid> first, IReadOnlyList<Guid> second)
+    {
+        var merged = new List<Guid>(first.Count + second.Count);
+        for (var index = 0; index < Math.Max(first.Count, second.Count); index++)
+        {
+            if (index < first.Count)
+                merged.Add(first[index]);
+            if (index < second.Count)
+                merged.Add(second[index]);
+        }
+
+        return merged;
+    }
+
+    private async Task ReplaceMixesAsync(long userId, IReadOnlyList<MixDraft> drafts, CancellationToken cancellationToken)
+    {
+        var previousMixes = await database.Mixes
+            .Where(mix => mix.UserId == userId)
+            .ToListAsync(cancellationToken);
+
+        if (previousMixes.Count > 0)
+        {
+            database.Mixes.RemoveRange(previousMixes);
+        }
+
+        for (var position = 0; position < drafts.Count; position++)
+        {
+            var draft = drafts[position];
+            var mix = new Mix
             {
-                var previousIds = previousMixes.Select(mix => mix.Id).ToList();
-                var previousItems = await database.MixItems
-                    .Where(item => previousIds.Contains(item.MixId))
-                    .ToListAsync(cancellationToken);
+                UserId = userId,
+                Kind = draft.Kind,
+                Position = position
+            };
 
-                database.MixItems.RemoveRange(previousItems);
-                database.Mixes.RemoveRange(previousMixes);
-            }
+            await database.Mixes.AddAsync(mix, cancellationToken);
 
-            for (var position = 0; position < drafts.Count; position++)
+            for (var itemPosition = 0; itemPosition < draft.TrackIds.Count; itemPosition++)
             {
-                var draft = drafts[position];
-                var mix = new Mix
+                await database.MixItems.AddAsync(new MixItem
                 {
-                    UserId = userId,
-                    Title = draft.Title,
-                    Subtitle = draft.Subtitle,
-                    Position = position
-                };
-
-                await database.Mixes.AddAsync(mix, cancellationToken);
-
-                for (var itemPosition = 0; itemPosition < draft.TrackIds.Count; itemPosition++)
-                {
-                    await database.MixItems.AddAsync(new MixItem
-                    {
-                        MixId = mix.Id,
-                        Position = itemPosition,
-                        TrackId = draft.TrackIds[itemPosition]
-                    }, cancellationToken);
-                }
+                    MixId = mix.Id,
+                    Position = itemPosition,
+                    TrackId = draft.TrackIds[itemPosition]
+                }, cancellationToken);
             }
         }
     }

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

@@ -3,29 +3,29 @@ using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Musify.Application.Contracts;
 using Musify.Application.Mixes.Responses;
+using Musify.Application.Shared;
 
-namespace Musify.Application.Mixes
+namespace Musify.Application.Mixes;
+
+public record GetMixByIdQuery(long UserId, Guid MixId)
+    : IQuery<ErrorOr<MixApplicationResponse>>;
+
+public class GetMixByIdQueryHandler(IDatabase database)
+    : IQueryHandler<GetMixByIdQuery, ErrorOr<MixApplicationResponse>>
 {
-    public record GetMixByIdQuery(long UserId, Guid MixId)
-        : IQuery<ErrorOr<MixApplicationResponse>>;
-
-    public class GetMixByIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetMixByIdQuery, ErrorOr<MixApplicationResponse>>
+    public async ValueTask<ErrorOr<MixApplicationResponse>> Handle(GetMixByIdQuery request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<MixApplicationResponse>> Handle(GetMixByIdQuery request, CancellationToken cancellationToken)
-        {
-            var mix = await database.Mixes
-                .AsNoTracking()
-                .Include(mix => mix.Items)
-                .SingleOrDefaultAsync(mix => mix.Id == request.MixId && mix.UserId == request.UserId, cancellationToken);
+        var mix = await database.Mixes
+            .AsNoTracking()
+            .Include(mix => mix.Items)
+            .SingleOrDefaultAsync(mix => mix.Id == request.MixId && mix.UserId == request.UserId, cancellationToken);
 
-            if (mix == null)
-                return Error.NotFound(description: $"Mix {request.MixId} was not found");
+        if (mix == null)
+            return AppErrors.NotFound("Mix", request.MixId);
 
-            var orderedItems = mix.Items.OrderBy(item => item.Position).ToList();
-            var items = await MixItemMapper.ToResponsesAsync(database, orderedItems, cancellationToken);
+        var orderedItems = mix.Items.OrderBy(item => item.Position).ToList();
+        var items = await MixItemMapper.ToResponsesAsync(database, orderedItems, cancellationToken);
 
-            return new MixApplicationResponse(mix.Id, mix.Title, mix.Subtitle, items.Count, items);
-        }
+        return new MixApplicationResponse(mix.Id, mix.Kind, items.Count, items);
     }
 }

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

@@ -1,37 +1,50 @@
-using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Musify.Application.Contracts;
 using Musify.Application.Mixes.Responses;
 
-namespace Musify.Application.Mixes
+namespace Musify.Application.Mixes;
+
+public record GetMixesByUserIdQuery(long UserId)
+    : IQuery<IReadOnlyList<MixApplicationResponse>>;
+
+public class GetMixesByUserIdQueryHandler(IDatabase database)
+    : IQueryHandler<GetMixesByUserIdQuery, IReadOnlyList<MixApplicationResponse>>
 {
-    public record GetMixesByUserIdQuery(long UserId)
-        : IQuery<ErrorOr<IReadOnlyList<MixApplicationResponse>>>;
-
-    public class GetMixesByUserIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetMixesByUserIdQuery, ErrorOr<IReadOnlyList<MixApplicationResponse>>>
+    public async ValueTask<IReadOnlyList<MixApplicationResponse>> Handle(GetMixesByUserIdQuery request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<IReadOnlyList<MixApplicationResponse>>> Handle(GetMixesByUserIdQuery request, CancellationToken cancellationToken)
+        var mixes = await database.Mixes
+            .AsNoTracking()
+            .Where(mix => mix.UserId == request.UserId)
+            .Include(mix => mix.Items)
+            .OrderBy(mix => mix.Position)
+            .ThenBy(mix => mix.Id)
+            .ToListAsync(cancellationToken);
+
+        var orderedItemsByMix = mixes.ToDictionary(
+            mix => mix.Id,
+            mix => mix.Items.OrderBy(item => item.Position).ToList());
+
+        var coverItems = orderedItemsByMix.Values
+            .SelectMany(items => items.Take(MixApplicationResponse.CoverItemCount))
+            .ToList();
+        var coverResponses = (await MixItemMapper.ToResponsesAsync(database, coverItems, cancellationToken))
+            .GroupBy(response => response.TrackId)
+            .ToDictionary(group => group.Key, group => group.First());
+
+        var responses = new List<MixApplicationResponse>(mixes.Count);
+        foreach (var mix in mixes)
         {
-            var mixes = await database.Mixes
-                .AsNoTracking()
-                .Where(mix => mix.UserId == request.UserId)
-                .Include(mix => mix.Items)
-                .OrderBy(mix => mix.Position)
-                .ToListAsync(cancellationToken);
+            var orderedItems = orderedItemsByMix[mix.Id];
+            var covers = orderedItems
+                .Take(MixApplicationResponse.CoverItemCount)
+                .Where(item => coverResponses.ContainsKey(item.TrackId))
+                .Select(item => coverResponses[item.TrackId])
+                .ToList();
 
-            var responses = new List<MixApplicationResponse>(mixes.Count);
-            foreach (var mix in mixes)
-            {
-                var orderedItems = mix.Items.OrderBy(item => item.Position).ToList();
-                var coverItems = await MixItemMapper.ToResponsesAsync(
-                    database, orderedItems.Take(MixApplicationResponse.CoverItemCount).ToList(), cancellationToken);
-
-                responses.Add(new MixApplicationResponse(mix.Id, mix.Title, mix.Subtitle, orderedItems.Count, coverItems));
-            }
-
-            return responses;
+            responses.Add(new MixApplicationResponse(mix.Id, mix.Kind, orderedItems.Count, covers));
         }
+
+        return responses;
     }
 }

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

@@ -2,39 +2,39 @@ using Microsoft.EntityFrameworkCore;
 using Musify.Application.Contracts;
 using Musify.Application.Mixes.Responses;
 using Musify.Domain.Entities;
+using Musify.Domain.ValueObjects;
 
-namespace Musify.Application.Mixes
+namespace Musify.Application.Mixes;
+
+
+internal static class MixItemMapper
 {
-
-    internal static class MixItemMapper
+    public static async Task<List<MixItemApplicationResponse>> ToResponsesAsync(
+        IDatabase database,
+        IReadOnlyList<MixItem> orderedItems,
+        CancellationToken cancellationToken)
     {
-        public static async Task<List<MixItemApplicationResponse>> ToResponsesAsync(
-            IDatabase database,
-            IReadOnlyList<MixItem> orderedItems,
-            CancellationToken cancellationToken)
-        {
-            var trackIds = orderedItems.Select(item => item.TrackId).Distinct().ToList();
+        var trackIds = orderedItems.Select(item => item.TrackId).Distinct().ToList();
 
-            var tracksById = await database.Tracks
-                .AsNoTracking()
-                .Include(track => track.Owner)
-                .Where(track => trackIds.Contains(track.Id))
-                .Select(track => new { Track = track, ListensCount = track.ListeningHistories.Count(l => l.IsCounted) })
-                .ToDictionaryAsync(x => x.Track.Id, cancellationToken);
+        var tracksById = await database.Tracks
+            .AsNoTracking()
+            .Include(track => track.Owner)
+            .Where(track => trackIds.Contains(track.Id) && track.LifeCycleStatus == LifeCycleStatus.Active)
+            .Select(track => new { Track = track, ListensCount = track.ListeningHistories.Count(l => l.IsCounted) })
+            .ToDictionaryAsync(x => x.Track.Id, cancellationToken);
 
-            return orderedItems
-                .Where(item => tracksById.ContainsKey(item.TrackId))
-                .Select(item =>
-                {
-                    var entry = tracksById[item.TrackId];
-                    return new MixItemApplicationResponse(
-                        item.TrackId,
-                        entry.Track.Title,
-                        entry.Track.Owner.Name,
-                        entry.Track.DurationSeconds,
-                        entry.ListensCount);
-                })
-                .ToList();
-        }
+        return orderedItems
+            .Where(item => tracksById.ContainsKey(item.TrackId))
+            .Select(item =>
+            {
+                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/MixApplicationResponse.cs

@@ -1,12 +1,12 @@
-namespace Musify.Application.Mixes.Responses
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.Mixes.Responses;
+
+public record MixApplicationResponse(
+    Guid Id,
+    MixKind Kind,
+    int ItemCount,
+    IReadOnlyList<MixItemApplicationResponse> Items)
 {
-    public record MixApplicationResponse(
-        Guid Id,
-        string Title,
-        string? Subtitle,
-        int ItemCount,
-        IReadOnlyList<MixItemApplicationResponse> Items)
-    {
-        public const int CoverItemCount = 4;
-    }
+    public const int CoverItemCount = 4;
 }

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

@@ -1,9 +1,8 @@
-namespace Musify.Application.Mixes.Responses
-{
-    public record MixItemApplicationResponse(
-        Guid TrackId,
-        string Title,
-        string? Artist,
-        double DurationSeconds,
-        int ListensCount);
-}
+namespace Musify.Application.Mixes.Responses;
+
+public record MixItemApplicationResponse(
+    Guid TrackId,
+    string Title,
+    string? Artist,
+    double DurationSeconds,
+    int ListensCount);

backend/Core/Musify.Application/Pictures/GetCover.cs

@@ -0,0 +1,75 @@
+using ErrorOr;
+using Mediator;
+using Microsoft.EntityFrameworkCore;
+using MimeMapping;
+using Musify.Application.Configuration;
+using Musify.Application.Contracts;
+using Musify.Application.Shared;
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.Pictures;
+
+public enum CoverOwner
+{
+    Track,
+    Album,
+    PlayList
+}
+
+public record GetCoverQuery(CoverOwner Owner, Guid Id, PictureSize Size = PictureSize.Medium)
+    : IQuery<ErrorOr<CoverLocation>>;
+
+public record CoverLocation(string Bucket, string Key, string ContentType);
+
+public class GetCoverQueryHandler(
+    IDatabase database,
+    ApplicationStorageConfiguration storageConfiguration,
+    TrackConfiguration trackConfiguration,
+    AlbumConfiguration albumConfiguration,
+    PlayListConfiguration playListConfiguration)
+    : IQueryHandler<GetCoverQuery, ErrorOr<CoverLocation>>
+{
+    private sealed record CoverSource(long OwnerUserId, string? Original, string? Small, string? Medium, string? Large);
+
+    public async ValueTask<ErrorOr<CoverLocation>> Handle(GetCoverQuery request, CancellationToken cancellationToken)
+    {
+        var (source, routes) = request.Owner switch
+        {
+            CoverOwner.Track => (await database.Tracks.AsNoTracking()
+                .Where(t => t.Id == request.Id && t.LifeCycleStatus == LifeCycleStatus.Active)
+                .Select(t => new CoverSource(t.OwnerUserId, t.Pictures.OriginalName, t.Pictures.SmallName, t.Pictures.MediumName, t.Pictures.LargeName))
+                .SingleOrDefaultAsync(cancellationToken), trackConfiguration.Routes),
+            CoverOwner.Album => (await database.Albums.AsNoTracking()
+                .Where(a => a.Id == request.Id && a.LifeCycleStatus == LifeCycleStatus.Active && a.Pictures != null)
+                .Select(a => new CoverSource(a.OwnerUserId, a.Pictures!.OriginalName, a.Pictures.SmallName, a.Pictures.MediumName, a.Pictures.LargeName))
+                .SingleOrDefaultAsync(cancellationToken), albumConfiguration.Routes),
+            _ => (await database.PlayLists.AsNoTracking()
+                .Where(p => p.Id == request.Id && p.LifeCycleStatus == LifeCycleStatus.Active && p.Pictures != null)
+                .Select(p => new CoverSource(p.OwnerUserId, p.Pictures!.OriginalName, p.Pictures.SmallName, p.Pictures.MediumName, p.Pictures.LargeName))
+                .SingleOrDefaultAsync(cancellationToken), playListConfiguration.Routes)
+        };
+
+        var entity = request.Owner.ToString();
+        if (source == null)
+            return AppErrors.NotFound($"{entity}Cover", request.Id);
+
+        var resizedName = request.Size switch
+        {
+            PictureSize.Small => source.Small,
+            PictureSize.Large => source.Large,
+            _ => source.Medium
+        };
+
+        // The resized files only exist once processing has finished; until then serve the original.
+        var (name, key) = !string.IsNullOrEmpty(resizedName)
+            ? (resizedName, routes.BuildPicturePath(request.Size, resizedName))
+            : !string.IsNullOrEmpty(source.Original)
+                ? (source.Original, routes.BuildOriginalPicturePath(source.OwnerUserId, source.Original))
+                : (null, null);
+
+        if (name == null || key == null)
+            return AppErrors.NotFound($"{entity}Cover", request.Id);
+
+        return new CoverLocation(storageConfiguration.Bucket, key, MimeUtility.GetMimeMapping(name));
+    }
+}

backend/Core/Musify.Application/Pictures/PictureSourceChange.cs

@@ -0,0 +1,35 @@
+using ErrorOr;
+using Musify.Application.Configuration;
+using Musify.Application.Services;
+using Musify.Application.Shared;
+using Musify.Domain.Entities;
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.Pictures;
+
+/// <summary>What an album or playlist needs to switch to a freshly uploaded picture.</summary>
+public sealed record PreparedPicture(UploadIntent Intent, EntityPictures Pictures, string FinalKey, ImageSizes Sizes);
+
+public static class PictureSourceChange
+{
+    public static async Task<ErrorOr<PreparedPicture>> PrepareAsync(
+        UploadIntentValidator uploadIntentValidator,
+        Guid intentId,
+        long userId,
+        UploadIntentPurpose purpose,
+        IPictureOwnerConfiguration owner,
+        CancellationToken cancellationToken)
+    {
+        var validation = await uploadIntentValidator.ValidateAndLoadAsync(intentId, userId, purpose, cancellationToken);
+        if (validation.IsError)
+            return validation.Errors;
+
+        var intent = validation.Value;
+
+        return new PreparedPicture(
+            intent,
+            EntityPictures.Pending(intent.ObjectName),
+            owner.Routes.BuildOriginalPicturePath(userId, intent.ObjectName),
+            owner.PicturesSizes.ToImageSizes(owner.Routes));
+    }
+}

backend/Core/Musify.Application/Pictures/Responses/PictureUploadResponse.cs

@@ -0,0 +1,10 @@
+namespace Musify.Application.Pictures.Responses;
+
+public record PictureUploadResponse(
+    Guid IntentId,
+    string Bucket,
+    string Key,
+    string PictureName,
+    string ContentType,
+    int ExpiresInSeconds,
+    string UploadUrl);

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

@@ -1,75 +0,0 @@
-using ErrorOr;
-using Mediator;
-using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.Logging;
-using Musify.Application.Contracts;
-using Musify.Domain.Entities;
-
-namespace Musify.Application.PlayLists
-{
-    public record AddTrackToPlayListCommand(long UserId, Guid PlayListId, Guid TrackId)
-        : ICommand<ErrorOr<Success>>;
-
-    public class AddTrackToPlayListCommandHandler(
-        IDatabase database,
-        ILogger<AddTrackToPlayListCommandHandler> logger)
-        : ICommandHandler<AddTrackToPlayListCommand, ErrorOr<Success>>
-    {
-        public async ValueTask<ErrorOr<Success>> Handle(AddTrackToPlayListCommand request, CancellationToken cancellationToken)
-        {
-            var playList = await database.PlayLists
-                .SingleOrDefaultAsync(pl => pl.Id == request.PlayListId, cancellationToken);
-            if (playList == null)
-            {
-                logger.LogInformation("Playlist {PlayListId} not found", request.PlayListId);
-                return Error.NotFound();
-            }
-
-            if (playList.UserId != request.UserId)
-            {
-                logger.LogWarning("User {UserId} is not the owner of playlist {PlayListId}", request.UserId, request.PlayListId);
-                return Error.Unauthorized();
-            }
-
-            var trackExists = await database.Tracks
-                .AsNoTracking()
-                .AnyAsync(t => t.Id == request.TrackId, cancellationToken);
-            if (!trackExists)
-            {
-                logger.LogInformation("Track {TrackId} not found", request.TrackId);
-                return Error.NotFound(description: $"Track {request.TrackId} not found");
-            }
-
-            var alreadyAdded = await database.PlayListHasTracks
-                .AsNoTracking()
-                .AnyAsync(plt => plt.PlayListId == request.PlayListId && plt.TrackId == request.TrackId, cancellationToken);
-            if (alreadyAdded)
-            {
-                logger.LogInformation("Track {TrackId} already in playlist {PlayListId}", request.TrackId, request.PlayListId);
-                return Error.Conflict(description: "Track is already in the playlist.");
-            }
-
-            var playListTracksQuery = database.PlayListHasTracks
-                .Where(plt => plt.PlayListId == request.PlayListId);
-
-            var hasTracks = await playListTracksQuery.AnyAsync(cancellationToken);
-            var nextPosition = hasTracks
-                ? await playListTracksQuery.MaxAsync(plt => plt.Position, cancellationToken) + 1
-                : 0;
-
-            await database.PlayListHasTracks.AddAsync(new PlayListHasTrack
-            {
-                PlayListId = request.PlayListId,
-                TrackId = request.TrackId,
-                Position = nextPosition
-            }, cancellationToken);
-
-            await database.SaveChangesAsync(cancellationToken);
-
-            logger.LogInformation("Added track {TrackId} to playlist {PlayListId} at position {Position}",
-                request.TrackId, request.PlayListId, nextPosition);
-
-            return new Success();
-        }
-    }
-}

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

@@ -0,0 +1,73 @@
+using ErrorOr;
+using Mediator;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+using Musify.Application.Contracts;
+using Musify.Application.Shared;
+using Musify.Domain.Entities;
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.PlayLists;
+
+/// <summary>Appends tracks to a playlist in the given order, skipping the ones it already has.</summary>
+public record AddTracksToPlayListCommand(long UserId, Guid PlayListId, IReadOnlyList<Guid> TrackIds)
+    : ICommand<ErrorOr<Success>>;
+
+public class AddTracksToPlayListCommandHandler(
+    IDatabase database,
+    ILogger<AddTracksToPlayListCommandHandler> logger)
+    : ICommandHandler<AddTracksToPlayListCommand, ErrorOr<Success>>
+{
+    public async ValueTask<ErrorOr<Success>> Handle(AddTracksToPlayListCommand request, CancellationToken cancellationToken)
+    {
+        var playList = await database.PlayLists.FindOwnedAsync(request.PlayListId, request.UserId, cancellationToken);
+        if (playList.IsError)
+            return playList.Errors;
+
+        var requestedIds = request.TrackIds.Distinct().ToList();
+
+        var existingIds = await database.Tracks
+            .AsNoTracking()
+            .Where(track => requestedIds.Contains(track.Id) && track.LifeCycleStatus == LifeCycleStatus.Active)
+            .Select(track => track.Id)
+            .ToListAsync(cancellationToken);
+
+        var missing = requestedIds.FirstOrDefault(id => !existingIds.Contains(id));
+        if (missing != Guid.Empty)
+            return AppErrors.NotFound("Track", missing);
+
+        var alreadyInPlayList = await database.PlayListHasTracks
+            .AsNoTracking()
+            .Where(link => link.PlayListId == request.PlayListId && requestedIds.Contains(link.TrackId))
+            .Select(link => link.TrackId)
+            .ToListAsync(cancellationToken);
+
+        var toAdd = requestedIds.Where(id => !alreadyInPlayList.Contains(id)).ToList();
+        if (toAdd.Count == 0)
+            return Result.Success;
+
+        // Playlist positions are internal indexes, so they start at 0.
+        var nextPosition = (await database.PlayListHasTracks
+            .Where(link => link.PlayListId == request.PlayListId)
+            .MaxAsync(link => (int?)link.Position, cancellationToken) ?? -1) + 1;
+
+        foreach (var trackId in toAdd)
+        {
+            await database.PlayListHasTracks.AddAsync(new PlayListHasTrack
+            {
+                PlayListId = request.PlayListId,
+                TrackId = trackId,
+                Position = nextPosition++
+            }, cancellationToken);
+        }
+
+        var saved = await database.TrySaveChangesAsync(
+            AppErrors.Conflict("PlayList.ConcurrentChange", "The playlist changed while adding tracks. Try again."), cancellationToken);
+        if (saved.IsError)
+            return saved;
+
+        logger.LogInformation("Added {Count} tracks to playlist {PlayListId}", toAdd.Count, request.PlayListId);
+
+        return Result.Success;
+    }
+}

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

@@ -3,144 +3,76 @@ using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
 using Musify.Application.Configuration;
-using Musify.Application.Shared;
+using Musify.Application.Contracts;
 using Musify.Application.Events;
+using Musify.Application.Pictures;
 using Musify.Application.PlayLists.Responses;
 using Musify.Application.Services;
+using Musify.Application.Shared;
 using Musify.Domain.Entities;
 using Musify.Domain.ValueObjects;
-using Musify.Application.Contracts;
 
-namespace Musify.Application.PlayLists
+namespace Musify.Application.PlayLists;
+
+public record CreatePlayListCommand(
+    long UserId,
+    string Name,
+    string? Description,
+    Guid? PictureIntentId,
+    PlayListVisibility Visibility = PlayListVisibility.Private)
+    : ICommand<ErrorOr<PlayListApplicationResponse>>;
+
+public class CreatePlayListCommandHandler(
+    IEventBus eventBus,
+    IDatabase database,
+    UploadIntentValidator uploadIntentValidator,
+    ILogger<CreatePlayListCommandHandler> logger,
+    PlayListConfiguration playListConfiguration)
+    : ICommandHandler<CreatePlayListCommand, ErrorOr<PlayListApplicationResponse>>
 {
-    public record CreatePlayListCommand(
-        long UserId,
-        string Name,
-        string? Description,
-        Guid? PictureIntentId,
-        PlaylistVisibility Visibility = PlaylistVisibility.Private)
-        : ICommand<ErrorOr<PlayListApplicationResponse>>;
-
-    public class CreatePlayListCommandHandler(
-        IEventBus eventBus,
-        IDatabase database,
-        UploadIntentValidator uploadIntentValidator,
-        ILogger<CreatePlayListCommandHandler> logger,
-        ApplicationStorageConfiguration storageConfiguration,
-        PlayListConfiguration playListConfiguration,
-        UploadIntentConfiguration uploadIntentConfiguration)
-        : ICommandHandler<CreatePlayListCommand, ErrorOr<PlayListApplicationResponse>>
+    public async ValueTask<ErrorOr<PlayListApplicationResponse>> Handle(CreatePlayListCommand request, CancellationToken cancellationToken)
     {
-        private sealed record ResolvedPlayListPictures(PlayListPictures? Pictures, UploadIntent? Intent);
+        var userExists = await database.Users
+            .AsNoTracking()
+            .AnyAsync(u => u.Id == request.UserId, cancellationToken);
+        if (!userExists)
+            return AppErrors.NotFound("User", request.UserId);
 
-        public async ValueTask<ErrorOr<PlayListApplicationResponse>> Handle(CreatePlayListCommand request, CancellationToken cancellationToken)
+        PreparedPicture? picture = null;
+        if (request.PictureIntentId is { } intentId)
         {
-            var userExists = await database.Users
-                .AsNoTracking()
-                .AnyAsync(u => u.Id == request.UserId, cancellationToken);
-            if (!userExists)
-            {
-                logger.LogWarning("User {UserId} not found", request.UserId);
-                return Error.NotFound(description: $"User {request.UserId} not found");
-            }
+            var prepared = await PictureSourceChange.PrepareAsync(
+                uploadIntentValidator, intentId, request.UserId, UploadIntentPurpose.PlayListPicture, playListConfiguration, cancellationToken);
+            if (prepared.IsError)
+                return prepared.Errors;
 
-            var picturesResult = await ResolvePicturesAsync(request, cancellationToken);
-            if (picturesResult.IsError)
-                return picturesResult.Errors;
-
-            var resolvedPictures = picturesResult.Value;
-
-            var playList = new PlayList
-            {
-                UserId = request.UserId,
-                Name = request.Name,
-                NormalizedName = request.Name.Trim().ToUpperInvariant(),
-                Description = string.IsNullOrWhiteSpace(request.Description) ? null : request.Description.Trim(),
-                Pictures = resolvedPictures.Pictures,
-                Visibility = request.Visibility
-            };
-            await database.PlayLists.AddAsync(playList, cancellationToken);
-
-            if (resolvedPictures.Intent != null)
-            {
-                var finalPictureKey = playListConfiguration.Routes.BuildOriginalPicturePath(request.UserId, resolvedPictures.Pictures!.OriginalName);
-                var publishResult = await PublishCreatePlayListEventAsync(playList.Id, resolvedPictures.Intent, finalPictureKey, cancellationToken);
-                if (publishResult.IsError)
-                    return publishResult.Errors;
-            }
-
-            try
-            {
-                await database.SaveChangesAsync(cancellationToken);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to save playlist for user {UserId}", request.UserId);
-                return Error.Failure(description: $"Failed to create playlist for user {request.UserId}");
-            }
-
-            logger.LogInformation("Created playlist {PlayListId} for user {UserId}", playList.Id, request.UserId);
-            return PlayListApplicationResponse.FromEntity(playList);
+            picture = prepared.Value;
         }
 
-        private async ValueTask<ErrorOr<ResolvedPlayListPictures>> ResolvePicturesAsync(
-            CreatePlayListCommand request, CancellationToken cancellationToken)
+        var name = request.Name.Trim();
+        var playList = new PlayList
         {
-            if (!request.PictureIntentId.HasValue)
-            {
-                return new ResolvedPlayListPictures(null, null);
-            }
+            OwnerUserId = request.UserId,
+            Name = name,
+            NormalizedName = TextNormalizer.Normalize(name),
+            Description = string.IsNullOrWhiteSpace(request.Description) ? null : request.Description.Trim(),
+            Pictures = picture?.Pictures,
+            Visibility = request.Visibility
+        };
+        await database.PlayLists.AddAsync(playList, cancellationToken);
 
-            var validation = await uploadIntentValidator.ValidateAndLoadAsync(
-                uploadIntentConfiguration, request.PictureIntentId.Value, request.UserId, cancellationToken);
-
-            if (validation.IsError)
-                return validation.Errors;
-
-            return new ResolvedPlayListPictures(new PlayListPictures
-            {
-                OriginalName = validation.Value.ObjectName,
-                SmallName = validation.Value.ObjectName,
-                MediumName = validation.Value.ObjectName,
-                LargeName = validation.Value.ObjectName
-            }, validation.Value);
+        if (picture != null)
+        {
+            await eventBus.PublishAsync(
+                new CreatePlayListResourcesEvent(
+                    playList.Id, picture.Intent.Id, picture.Intent.Bucket, picture.Intent.Key, picture.FinalKey, picture.Sizes),
+                cancellationToken);
         }
 
-        private async Task<ErrorOr<Success>> PublishCreatePlayListEventAsync(
-            Guid playListId,
-            UploadIntent pictureIntent,
-            string finalPictureKey,
-            CancellationToken cancellationToken)
-        {
-            try
-            {
-                await eventBus.PublishAsync(
-                    new CreatePlayListResourcesEvent(
-                        playListId,
-                        pictureIntent.Id,
-                        storageConfiguration.Bucket,
-                        pictureIntent.Key,
-                        finalPictureKey,
-                        new ImageSize(
-                            playListConfiguration.Routes.SmallPicturesPath,
-                            playListConfiguration.PicturesSizes.SmallPictureWidth,
-                            playListConfiguration.PicturesSizes.SmallPictureHeight),
-                        new ImageSize(
-                            playListConfiguration.Routes.MediumPicturesPath,
-                            playListConfiguration.PicturesSizes.MediumPictureWidth,
-                            playListConfiguration.PicturesSizes.MediumPictureHeight),
-                        new ImageSize(
-                            playListConfiguration.Routes.LargePicturesPath,
-                            playListConfiguration.PicturesSizes.LargePictureWidth,
-                            playListConfiguration.PicturesSizes.LargePictureHeight)),
-                    cancellationToken);
-                return new Success();
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to publish create playlist event for playlist {PlayListId}", playListId);
-                return Error.Failure(description: $"Failed to publish create playlist event for playlist {playListId}");
-            }
-        }
+        await database.SaveChangesAsync(cancellationToken);
+
+        logger.LogInformation("Created playlist {PlayListId} for user {UserId}", playList.Id, request.UserId);
+
+        return PlayListApplicationResponse.FromEntity(playList);
     }
 }

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

@@ -1,62 +1,36 @@
 using ErrorOr;
 using Mediator;
-using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
 using Musify.Application.Contracts;
 using Musify.Application.Events;
+using Musify.Application.Shared;
 using Musify.Domain.ValueObjects;
 
-namespace Musify.Application.PlayLists
+namespace Musify.Application.PlayLists;
+
+public record DeletePlayListCommand(long UserId, Guid PlayListId)
+    : ICommand<ErrorOr<Success>>;
+
+public class DeletePlayListCommandHandler(
+    IDatabase database,
+    IEventBus eventBus,
+    ILogger<DeletePlayListCommandHandler> logger)
+    : ICommandHandler<DeletePlayListCommand, ErrorOr<Success>>
 {
-    public record DeletePlayListCommand(long UserId, Guid PlayListId)
-        : ICommand<ErrorOr<Success>>;
-
-    public class DeletePlayListCommandHandler(
-        IDatabase database,
-        IEventBus eventBus,
-        ILogger<DeletePlayListCommandHandler> logger)
-        : ICommandHandler<DeletePlayListCommand, ErrorOr<Success>>
+    public async ValueTask<ErrorOr<Success>> Handle(DeletePlayListCommand request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<Success>> Handle(DeletePlayListCommand request, CancellationToken cancellationToken)
-        {
-            var playList = await database.PlayLists.SingleOrDefaultAsync(p => p.Id == request.PlayListId, cancellationToken);
-            if (playList == null)
-            {
-                logger.LogDebug("Playlist {PlayListId} not found", request.PlayListId);
-                return Error.NotFound();
-            }
+        var found = await database.PlayLists.FindOwnedAsync(request.PlayListId, request.UserId, cancellationToken);
+        if (found.IsError)
+            return found.Errors;
 
-            if (playList.UserId != request.UserId)
-            {
-                logger.LogWarning("Playlist {PlayListId} does not belong to user {UserId}", request.PlayListId, request.UserId);
-                return Error.Unauthorized();
-            }
+        var playList = found.Value;
+        playList.LifeCycleStatus = LifeCycleStatus.Removing;
 
-            playList.LifeCycleStatus = LifeCycleStatus.Removing;
+        await eventBus.PublishAsync(new DeletePlayListEvent(playList.Id, request.UserId), cancellationToken);
+        await database.SaveChangesAsync(cancellationToken);
 
-            try
-            {
-                await eventBus.PublishAsync(
-                    new DeletePlayListEvent(playList.Id, request.UserId),
-                    cancellationToken);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to publish delete playlist event for playlist {PlayListId}", request.PlayListId);
-                return Error.Failure(description: $"Failed to delete playlist {request.PlayListId}");
-            }
+        logger.LogInformation("Marked playlist {PlayListId} as removing", request.PlayListId);
 
-            try
-            {
-                await database.SaveChangesAsync(cancellationToken);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to mark playlist {PlayListId} as removing", request.PlayListId);
-                return Error.Failure(description: $"Failed to delete playlist {request.PlayListId}");
-            }
-
-            return new Success();
-        }
+        return Result.Success;
     }
 }

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

@@ -1,42 +1,30 @@
 using ErrorOr;
-using Microsoft.EntityFrameworkCore;
-using Musify.Application.PlayLists.Responses;
 using Mediator;
+using Microsoft.EntityFrameworkCore;
 using Musify.Application.Contracts;
-using Musify.Domain.ValueObjects;
+using Musify.Application.PlayLists.Responses;
+using Musify.Application.Shared;
 
-namespace Musify.Application.PlayLists
+namespace Musify.Application.PlayLists;
+
+public record GetPlayListByIdQuery(Guid Id, long? RequestingUserId = null)
+    : IQuery<ErrorOr<PlayListApplicationResponse>>;
+
+public class GetPlayListByIdQueryHandler(IDatabase database)
+    : IQueryHandler<GetPlayListByIdQuery, ErrorOr<PlayListApplicationResponse>>
 {
-    public record GetPlayListByIdQuery(Guid Id, long? RequestingUserId = null)
-        : IQuery<ErrorOr<PlayListApplicationResponse>>;
-
-    public class GetPlayListByIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetPlayListByIdQuery, ErrorOr<PlayListApplicationResponse>>
+    public async ValueTask<ErrorOr<PlayListApplicationResponse>> Handle(GetPlayListByIdQuery request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<PlayListApplicationResponse>> Handle(GetPlayListByIdQuery request, CancellationToken cancellationToken)
-        {
-            var entry = await database.PlayLists
-                .AsNoTracking()
-                .Where(p => p.Id == request.Id)
-                .Select(p => new
-                {
-                    PlayList = p,
-                    CoverTrackIds = p.PlayListTracks
-                        .OrderBy(plt => plt.Position)
-                        .Take(PlayListApplicationResponse.CoverTrackCount)
-                        .Select(plt => plt.TrackId)
-                        .ToList()
-                })
-                .SingleOrDefaultAsync(cancellationToken);
+        var playList = await database.PlayLists
+            .AsNoTracking()
+            .Active()
+            .VisibleTo(request.RequestingUserId)
+            .Where(p => p.Id == request.Id)
+            .SelectResponse()
+            .SingleOrDefaultAsync(cancellationToken);
 
-            if (entry == null)
-                return Error.NotFound();
-
-            if (entry.PlayList.Visibility == PlaylistVisibility.Private
-                && entry.PlayList.UserId != request.RequestingUserId)
-                return Error.NotFound();
-
-            return PlayListApplicationResponse.FromEntity(entry.PlayList, entry.CoverTrackIds);
-        }
+        return playList == null
+            ? AppErrors.NotFound("PlayList", request.Id)
+            : playList;
     }
 }

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

@@ -1,49 +0,0 @@
-using ErrorOr;
-using Mediator;
-using Microsoft.EntityFrameworkCore;
-using MimeMapping;
-using Musify.Application.Configuration;
-using Musify.Application.Contracts;
-
-namespace Musify.Application.PlayLists
-{
-    public record GetPlayListCoverQuery(Guid PlayListId, string Size)
-        : IQuery<ErrorOr<PlayListCoverLocation>>;
-
-    public record PlayListCoverLocation(string Bucket, string Key, string ContentType);
-
-    public class GetPlayListCoverQueryHandler(
-        IDatabase database,
-        ApplicationStorageConfiguration storageConfiguration,
-        PlayListConfiguration playListConfiguration)
-        : IQueryHandler<GetPlayListCoverQuery, ErrorOr<PlayListCoverLocation>>
-    {
-        public async ValueTask<ErrorOr<PlayListCoverLocation>> Handle(GetPlayListCoverQuery request, CancellationToken cancellationToken)
-        {
-            var pictures = await database.PlayLists.AsNoTracking()
-                .Where(p => p.Id == request.PlayListId)
-                .Select(p => p.Pictures)
-                .SingleOrDefaultAsync(cancellationToken);
-
-            if (pictures == null)
-                return Error.NotFound();
-
-            var routes = playListConfiguration.Routes;
-            var (name, key) = request.Size.ToLowerInvariant() switch
-            {
-                "small" => (pictures.SmallName, BuildKey(routes.BuildSmallPicturePath, pictures.SmallName)),
-                "large" => (pictures.LargeName, BuildKey(routes.BuildLargePicturePath, pictures.LargeName)),
-                _ => (pictures.MediumName, BuildKey(routes.BuildMediumPicturePath, pictures.MediumName))
-            };
-
-            if (string.IsNullOrEmpty(name) || string.IsNullOrEmpty(key))
-                return Error.NotFound();
-
-            var contentType = MimeUtility.GetMimeMapping(name);
-            return new PlayListCoverLocation(storageConfiguration.Bucket, key, contentType);
-        }
-
-        private static string? BuildKey(Func<string, string> builder, string? name)
-            => string.IsNullOrEmpty(name) ? null : builder(name);
-    }
-}

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

@@ -2,48 +2,40 @@ using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Musify.Application.Contracts;
+using Musify.Application.PlayLists.Responses;
 using Musify.Application.Shared;
 using Musify.Application.Tracks.Responses;
-using X.PagedList;
-using X.PagedList.EF;
+using Musify.Domain.ValueObjects;
 
-namespace Musify.Application.PlayLists
+namespace Musify.Application.PlayLists;
+
+public record GetPlayListTracksQuery(
+    Guid PlayListId,
+    int PageNumber,
+    int PageSize,
+    long? ViewerId = null)
+    : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse>>>;
+
+public class GetPlayListTracksQueryHandler(IDatabase database)
+    : IQueryHandler<GetPlayListTracksQuery, ErrorOr<PaginatedResponse<TrackApplicationResponse>>>
 {
-    public record GetPlayListTracksQuery(
-        Guid PlayListId,
-        int PageNumber,
-        int PageSize)
-        : IQuery<ErrorOr<PaginatedResponse<TrackApplicationResponse>>>;
-
-    public class GetPlayListTracksQueryHandler(IDatabase database)
-        : 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()
-                .AnyAsync(p => p.Id == request.PlayListId, cancellationToken);
-            if (!playListExists)
-                return Error.NotFound();
+        var playListVisible = await database.PlayLists
+            .AsNoTracking()
+            .Active()
+            .VisibleTo(request.ViewerId)
+            .AnyAsync(playList => playList.Id == request.PlayListId, cancellationToken);
+        if (!playListVisible)
+            return AppErrors.NotFound("PlayList", request.PlayListId);
 
-            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);
-
-            var pagedEntities = await tracksQuery
-                .OrderBy(plt => plt.Position)
-                .Select(plt => new { plt.Track, ListensCount = plt.Track.ListeningHistories.Count(l => l.IsCounted) })
-                .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
-
-            var pagedTracks = new StaticPagedList<TrackApplicationResponse>(
-                pagedEntities.Select(x => TrackApplicationResponse.FromEntity(x.Track, x.ListensCount)),
-                pagedEntities.PageNumber, pagedEntities.PageSize, pagedEntities.TotalItemCount);
-
-            return PaginatedResponse<TrackApplicationResponse>.FromPagedList(pagedTracks);
-        }
+        return await database.PlayListHasTracks
+            .AsNoTracking()
+            .Where(playListTrack => playListTrack.PlayListId == request.PlayListId && playListTrack.Track.LifeCycleStatus == LifeCycleStatus.Active)
+            .OrderBy(playListTrack => playListTrack.Position)
+            .ThenBy(playListTrack => playListTrack.Id)
+            .Select(playListTrack => playListTrack.Track)
+            .SelectResponse()
+            .ToPaginatedAsync(new PageRequest(request.PageNumber, request.PageSize), cancellationToken);
     }
 }

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

@@ -1,43 +0,0 @@
-using ErrorOr;
-using Microsoft.EntityFrameworkCore;
-using Musify.Application.Shared;
-using Musify.Application.PlayLists.Responses;
-using X.PagedList;
-using X.PagedList.EF;
-using Mediator;
-using Musify.Application.Contracts;
-
-namespace Musify.Application.PlayLists
-{
-    public record GetPlayListsQuery(int PageNumber, int PageSize)
-        : IQuery<ErrorOr<PaginatedResponse<PlayListApplicationResponse>>>;
-
-    public class GetPlayListsQueryHandler(IDatabase database)
-        : IQueryHandler<GetPlayListsQuery, ErrorOr<PaginatedResponse<PlayListApplicationResponse>>>
-    {
-        public async ValueTask<ErrorOr<PaginatedResponse<PlayListApplicationResponse>>> Handle(GetPlayListsQuery request, CancellationToken cancellationToken)
-        {
-            var totalCount = await database.PlayLists.CountAsync(cancellationToken);
-
-            var pagedEntities = await database.PlayLists
-                .AsNoTracking()
-                .OrderBy(p => p.Id)
-                .Select(p => new
-                {
-                    PlayList = p,
-                    CoverTrackIds = p.PlayListTracks
-                        .OrderBy(plt => plt.Position)
-                        .Take(PlayListApplicationResponse.CoverTrackCount)
-                        .Select(plt => plt.TrackId)
-                        .ToList()
-                })
-                .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
-
-            var pagedPlayLists = new StaticPagedList<PlayListApplicationResponse>(
-                pagedEntities.Select(entry => PlayListApplicationResponse.FromEntity(entry.PlayList, entry.CoverTrackIds)),
-                pagedEntities.PageNumber, pagedEntities.PageSize, pagedEntities.TotalItemCount);
-
-            return PaginatedResponse<PlayListApplicationResponse>.FromPagedList(pagedPlayLists);
-        }
-    }
-}

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

@@ -1,64 +1,40 @@
-using ErrorOr;
 using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Musify.Application.Contracts;
 using Musify.Application.PlayLists.Responses;
 using Musify.Application.Shared;
-using Musify.Domain.ValueObjects;
-using X.PagedList;
-using X.PagedList.EF;
 
-namespace Musify.Application.PlayLists
+namespace Musify.Application.PlayLists;
+
+public record GetPlayListsByUserIdQuery(
+    long UserId,
+    string? Name,
+    int PageNumber,
+    int PageSize,
+    long? ViewerId = null)
+    : IQuery<PaginatedResponse<PlayListApplicationResponse>>;
+
+public class GetPlayListsByUserIdQueryHandler(IDatabase database)
+    : IQueryHandler<GetPlayListsByUserIdQuery, PaginatedResponse<PlayListApplicationResponse>>
 {
-    public record GetPlayListsByUserIdQuery(
-        long UserId,
-        string? Name,
-        int PageNumber,
-        int PageSize,
-        bool OnlyPublic = false)
-        : IQuery<ErrorOr<PaginatedResponse<PlayListApplicationResponse>>>;
-
-    public class GetPlayListsByUserIdQueryHandler(IDatabase database)
-        : IQueryHandler<GetPlayListsByUserIdQuery, ErrorOr<PaginatedResponse<PlayListApplicationResponse>>>
+    public async ValueTask<PaginatedResponse<PlayListApplicationResponse>> Handle(GetPlayListsByUserIdQuery request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<PaginatedResponse<PlayListApplicationResponse>>> Handle(GetPlayListsByUserIdQuery request, CancellationToken cancellationToken)
+        var playListsQuery = database.PlayLists
+            .AsNoTracking()
+            .Active()
+            .VisibleTo(request.ViewerId)
+            .Where(playList => playList.OwnerUserId == request.UserId);
+
+        if (!string.IsNullOrWhiteSpace(request.Name))
         {
-            var playListsQuery = database.PlayLists
-                .AsNoTracking()
-                .Where(p => p.UserId == request.UserId);
-
-            if (request.OnlyPublic)
-            {
-                playListsQuery = playListsQuery.Where(p => p.Visibility == PlaylistVisibility.Public);
-            }
-
-            if (!string.IsNullOrEmpty(request.Name))
-            {
-                var normalizedName = request.Name.Trim().ToUpperInvariant();
-                playListsQuery = playListsQuery.Where(p => p.NormalizedName.Contains(normalizedName));
-            }
-
-            var totalCount = await playListsQuery.CountAsync(cancellationToken);
-
-            var pagedEntities = await playListsQuery
-                .OrderBy(p => p.CreatedAt)
-                .Where(p => p.LifeCycleStatus == LifeCycleStatus.Active)
-                .Select(p => new
-                {
-                    PlayList = p,
-                    CoverTrackIds = p.PlayListTracks
-                        .OrderBy(plt => plt.Position)
-                        .Take(PlayListApplicationResponse.CoverTrackCount)
-                        .Select(plt => plt.TrackId)
-                        .ToList()
-                })
-                .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
-
-            var pagedPlayLists = new StaticPagedList<PlayListApplicationResponse>(
-                pagedEntities.Select(entry => PlayListApplicationResponse.FromEntity(entry.PlayList, entry.CoverTrackIds)),
-                pagedEntities.PageNumber, pagedEntities.PageSize, pagedEntities.TotalItemCount);
-
-            return PaginatedResponse<PlayListApplicationResponse>.FromPagedList(pagedPlayLists);
+            var normalizedName = TextNormalizer.Normalize(request.Name);
+            playListsQuery = playListsQuery.Where(playList => playList.NormalizedName.Contains(normalizedName));
         }
+
+        return await playListsQuery
+            .OrderBy(playList => playList.CreatedAt)
+            .ThenBy(playList => playList.Id)
+            .SelectResponse()
+            .ToPaginatedAsync(new PageRequest(request.PageNumber, request.PageSize), cancellationToken);
     }
 }

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

@@ -3,47 +3,43 @@ using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
 using Musify.Application.Contracts;
+using Musify.Application.Shared;
 
-namespace Musify.Application.PlayLists
+namespace Musify.Application.PlayLists;
+
+public record RemoveTrackFromPlayListCommand(long UserId, Guid PlayListId, Guid TrackId)
+    : ICommand<ErrorOr<Success>>;
+
+public class RemoveTrackFromPlayListCommandHandler(
+    IDatabase database,
+    ILogger<RemoveTrackFromPlayListCommandHandler> logger)
+    : ICommandHandler<RemoveTrackFromPlayListCommand, ErrorOr<Success>>
 {
-    public record RemoveTrackFromPlayListCommand(long UserId, Guid PlayListId, Guid TrackId)
-        : ICommand<ErrorOr<Success>>;
-
-    public class RemoveTrackFromPlayListCommandHandler(
-        IDatabase database,
-        ILogger<RemoveTrackFromPlayListCommandHandler> logger)
-        : ICommandHandler<RemoveTrackFromPlayListCommand, ErrorOr<Success>>
+    public async ValueTask<ErrorOr<Success>> Handle(RemoveTrackFromPlayListCommand request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<Success>> Handle(RemoveTrackFromPlayListCommand request, CancellationToken cancellationToken)
-        {
-            var playList = await database.PlayLists
-                .SingleOrDefaultAsync(pl => pl.Id == request.PlayListId, cancellationToken);
-            if (playList == null)
-            {
-                logger.LogInformation("Playlist {PlayListId} not found", request.PlayListId);
-                return Error.NotFound();
-            }
+        var playList = await database.PlayLists.FindOwnedAsync(request.PlayListId, request.UserId, cancellationToken);
+        if (playList.IsError)
+            return playList.Errors;
 
-            if (playList.UserId != request.UserId)
-            {
-                logger.LogWarning("User {UserId} is not the owner of playlist {PlayListId}", request.UserId, request.PlayListId);
-                return Error.Unauthorized();
-            }
+        var playListTracks = await database.PlayListHasTracks
+            .Where(plt => plt.PlayListId == request.PlayListId)
+            .OrderBy(plt => plt.Position)
+            .ToListAsync(cancellationToken);
 
-            var link = await database.PlayListHasTracks
-                .SingleOrDefaultAsync(plt => plt.PlayListId == request.PlayListId && plt.TrackId == request.TrackId, cancellationToken);
-            if (link == null)
-            {
-                logger.LogInformation("Track {TrackId} not in playlist {PlayListId}", request.TrackId, request.PlayListId);
-                return Error.NotFound(description: "Track is not in the playlist.");
-            }
+        var link = playListTracks.SingleOrDefault(plt => plt.TrackId == request.TrackId);
+        if (link == null)
+            return Error.NotFound("PlayList.TrackNotFound", "Track is not in the playlist.");
 
-            database.PlayListHasTracks.Remove(link);
-            await database.SaveChangesAsync(cancellationToken);
+        database.PlayListHasTracks.Remove(link);
 
-            logger.LogInformation("Removed track {TrackId} from playlist {PlayListId}", request.TrackId, request.PlayListId);
+        var position = 0;
+        foreach (var remaining in playListTracks.Where(plt => plt.Id != link.Id))
+            remaining.Position = position++;
 
-            return new Success();
-        }
+        await database.SaveChangesAsync(cancellationToken);
+
+        logger.LogInformation("Removed track {TrackId} from playlist {PlayListId}", request.TrackId, request.PlayListId);
+
+        return Result.Success;
     }
 }

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

@@ -1,105 +1,24 @@
 using ErrorOr;
 using Mediator;
-using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.Logging;
 using Musify.Application.Configuration;
-using Musify.Application.PlayLists.Responses;
+using Musify.Application.Pictures.Responses;
 using Musify.Application.Services;
-using Musify.Domain.Entities;
 using Musify.Domain.ValueObjects;
-using Musify.Application.Contracts;
 
-namespace Musify.Application.PlayLists
+namespace Musify.Application.PlayLists;
+
+public record RequestPlayListPictureUploadCommand(
+    long UserId,
+    string FileType,
+    string ContentType,
+    long? ExpectedSizeBytes = null)
+    : ICommand<ErrorOr<PictureUploadResponse>>;
+
+public class RequestPlayListPictureUploadCommandHandler(UploadIntentIssuer issuer, PlayListConfiguration playListConfiguration)
+    : ICommandHandler<RequestPlayListPictureUploadCommand, ErrorOr<PictureUploadResponse>>
 {
-    public record RequestPlayListPictureUploadCommand(
-        long UserId,
-        string FileType,
-        string ContentType,
-        long? ExpectedSizeBytes = null)
-        : ICommand<ErrorOr<PlayListPictureUploadResponse>>;
-
-    public class RequestPlayListPictureUploadCommandHandler(
-        IDatabase database,
-        UploadIntentValidator uploadIntentValidator,
-        IStorageService storageService,
-        ILogger<RequestPlayListPictureUploadCommandHandler> logger,
-        ApplicationStorageConfiguration storageConfiguration,
-        PlayListConfiguration playListConfiguration,
-        UploadIntentConfiguration uploadIntentConfiguration)
-        : ICommandHandler<RequestPlayListPictureUploadCommand, ErrorOr<PlayListPictureUploadResponse>>
-    {
-        public async ValueTask<ErrorOr<PlayListPictureUploadResponse>> Handle(RequestPlayListPictureUploadCommand request, CancellationToken cancellationToken)
-        {
-            var userExists = await database.Users
-                .AsNoTracking()
-                .AnyAsync(u => u.Id == request.UserId, cancellationToken);
-            if (!userExists)
-            {
-                logger.LogWarning("User {UserId} not found", request.UserId);
-                return Error.NotFound(description: $"User {request.UserId} not found");
-            }
-
-            var effectiveSizeBytes = request.ExpectedSizeBytes
-                ?? uploadIntentConfiguration.DefaultExpectedPictureSizeBytes;
-
-            var objectName = $"{Guid.NewGuid()}.{request.FileType.TrimStart('.').ToLowerInvariant()}";
-
-            var tempKey = playListConfiguration.Routes.BuildTempPicturePath(
-                uploadIntentConfiguration.TemporalRootPrefix, request.UserId, objectName);
-
-            try
-            {
-                var uploadUrl = await storageService.GetUploadUrlAsync(
-                    storageConfiguration.Bucket,
-                    tempKey,
-                    request.ContentType,
-                    TimeSpan.FromSeconds(uploadIntentConfiguration.UploadUrlExpiresInSeconds),
-                    cancellationToken);
-
-                await using var transaction = await database.BeginTransactionAsync(
-                    System.Data.IsolationLevel.Serializable, cancellationToken);
-
-                var quotaCheck = await uploadIntentValidator.CheckQuotaAsync(
-                    uploadIntentConfiguration,
-                    request.UserId, effectiveSizeBytes, 1, cancellationToken);
-                if (quotaCheck.IsError)
-                {
-                    logger.LogWarning("User {UserId} failed upload intent quota check", request.UserId);
-                    return quotaCheck.Errors;
-                }
-
-                var intent = new UploadIntent
-                {
-                    UserId = request.UserId,
-                    Bucket = storageConfiguration.Bucket,
-                    Key = tempKey,
-                    ObjectName = objectName,
-                    ContentType = request.ContentType,
-                    ExpectedSizeBytes = effectiveSizeBytes,
-                    Purpose = UploadIntentPurpose.PlayListPicture,
-                    ExpiresAt = DateTime.UtcNow.AddSeconds(uploadIntentConfiguration.UploadUrlExpiresInSeconds),
-                };
-
-                await database.UploadIntents.AddAsync(intent, cancellationToken);
-                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);
-
-                return new PlayListPictureUploadResponse(
-                    intent.Id,
-                    storageConfiguration.Bucket,
-                    tempKey,
-                    objectName,
-                    request.ContentType,
-                    uploadIntentConfiguration.UploadUrlExpiresInSeconds,
-                    uploadUrl);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to generate playlist picture upload URL for user {UserId}", request.UserId);
-                return Error.Failure(description: "Failed to generate upload URL");
-            }
-        }
-    }
+    public async ValueTask<ErrorOr<PictureUploadResponse>> Handle(RequestPlayListPictureUploadCommand request, CancellationToken cancellationToken) =>
+        await issuer.IssuePictureAsync(
+            request.UserId, UploadIntentPurpose.PlayListPicture, playListConfiguration,
+            request.FileType, request.ContentType, request.ExpectedSizeBytes, cancellationToken);
 }

backend/Core/Musify.Application/PlayLists/Responses/PlayListApplicationResponse.cs

@@ -1,37 +1,45 @@
 using Musify.Domain.Entities;
 using Musify.Domain.ValueObjects;
 
-namespace Musify.Application.PlayLists.Responses
-{
-    public record PlayListApplicationResponse(
-        Guid Id,
-        string Name,
-        string? Description,
-        string? SmallImageKeyName,
-        string? MediumImageKeyName,
-        string? LargeImageKeyName,
-        PlaylistVisibility Visibility,
-        DateTime CreatedAt,
-        DateTime UpdatedAt,
-        IReadOnlyList<Guid> CoverTrackIds)
-    {
-        public const int CoverTrackCount = 4;
 
-        public static PlayListApplicationResponse FromEntity(
-            PlayList playList,
-            IReadOnlyList<Guid>? coverTrackIds = null)
-        {
-            return new PlayListApplicationResponse(
-                playList.Id,
-                playList.Name,
-                playList.Description,
-                playList.Pictures?.SmallName,
-                playList.Pictures?.MediumName,
-                playList.Pictures?.LargeName,
-                playList.Visibility,
-                playList.CreatedAt,
-                playList.UpdatedAt,
-                coverTrackIds ?? []);
-        }
+namespace Musify.Application.PlayLists.Responses;
+
+public record PlayListApplicationResponse(
+    Guid Id,
+    string Name,
+    string? Description,
+    string? SmallImageKeyName,
+    string? MediumImageKeyName,
+    string? LargeImageKeyName,
+    PlayListVisibility Visibility,
+    DateTime CreatedAt,
+    DateTime UpdatedAt,
+    IReadOnlyList<Guid> CoverTrackIds,
+    long OwnerUserId,
+    int TrackCount,
+    double DurationSeconds)
+{
+    public const int CoverTrackCount = PlayListProjections.CoverTrackCount;
+
+    public static PlayListApplicationResponse FromEntity(
+        PlayList playList,
+        IReadOnlyList<Guid>? coverTrackIds = null,
+        int trackCount = 0,
+        double durationSeconds = 0)
+    {
+        return new PlayListApplicationResponse(
+            playList.Id,
+            playList.Name,
+            playList.Description,
+            playList.Pictures?.SmallName,
+            playList.Pictures?.MediumName,
+            playList.Pictures?.LargeName,
+            playList.Visibility,
+            playList.CreatedAt,
+            playList.UpdatedAt,
+            coverTrackIds ?? [],
+            playList.OwnerUserId,
+            trackCount,
+            durationSeconds);
     }
 }

backend/Core/Musify.Application/PlayLists/Responses/PlayListPictureUploadResponse.cs

@@ -1,11 +0,0 @@
-namespace Musify.Application.PlayLists.Responses
-{
-    public record PlayListPictureUploadResponse(
-        Guid IntentId,
-        string Bucket,
-        string Key,
-        string PictureName,
-        string ContentType,
-        int ExpiresInSeconds,
-        string UploadUrl);
-}

backend/Core/Musify.Application/PlayLists/Responses/PlayListProjections.cs

@@ -0,0 +1,37 @@
+using Musify.Domain.Entities;
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.PlayLists.Responses;
+
+public static class PlayListProjections
+{
+    public const int CoverTrackCount = 4;
+
+    public static IQueryable<PlayList> Active(this IQueryable<PlayList> query) =>
+        query.Where(playList => playList.LifeCycleStatus == LifeCycleStatus.Active);
+
+    public static IQueryable<PlayList> VisibleTo(this IQueryable<PlayList> query, long? viewerId) =>
+        query.Where(playList => playList.Visibility == PlayListVisibility.Public || playList.OwnerUserId == viewerId);
+
+    public static IQueryable<PlayListApplicationResponse> SelectResponse(this IQueryable<PlayList> query) =>
+        query.Select(playList => new PlayListApplicationResponse(
+            playList.Id,
+            playList.Name,
+            playList.Description,
+            playList.Pictures!.SmallName,
+            playList.Pictures!.MediumName,
+            playList.Pictures!.LargeName,
+            playList.Visibility,
+            playList.CreatedAt,
+            playList.UpdatedAt,
+            playList.PlayListTracks
+                .OrderBy(playListTrack => playListTrack.Position)
+                .Take(CoverTrackCount)
+                .Select(playListTrack => playListTrack.TrackId)
+                .ToList(),
+            playList.OwnerUserId,
+            playList.PlayListTracks.Count(playListTrack => playListTrack.Track.LifeCycleStatus == LifeCycleStatus.Active),
+            playList.PlayListTracks
+                .Where(playListTrack => playListTrack.Track.LifeCycleStatus == LifeCycleStatus.Active)
+                .Sum(playListTrack => playListTrack.Track.DurationSeconds)));
+}

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

@@ -3,153 +3,78 @@ using Mediator;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
 using Musify.Application.Configuration;
-using Musify.Application.Shared;
+using Musify.Application.Contracts;
 using Musify.Application.Events;
+using Musify.Application.Pictures;
 using Musify.Application.PlayLists.Responses;
 using Musify.Application.Services;
-using Musify.Domain.Entities;
+using Musify.Application.Shared;
 using Musify.Domain.ValueObjects;
-using Musify.Application.Contracts;
 
-namespace Musify.Application.PlayLists
+namespace Musify.Application.PlayLists;
+
+public record UpdatePlayListCommand(
+    long UserId,
+    Guid PlayListId,
+    string? NewName,
+    string? NewDescription,
+    Guid? NewPictureIntentId,
+    PlayListVisibility? NewVisibility = null)
+    : ICommand<ErrorOr<PlayListApplicationResponse>>;
+
+public class UpdatePlayListCommandHandler(
+    IEventBus eventBus,
+    IDatabase database,
+    UploadIntentValidator uploadIntentValidator,
+    ILogger<UpdatePlayListCommandHandler> logger,
+    PlayListConfiguration playListConfiguration)
+    : ICommandHandler<UpdatePlayListCommand, ErrorOr<PlayListApplicationResponse>>
 {
-    public record UpdatePlayListCommand(
-        long UserId,
-        Guid PlayListId,
-        string? NewName,
-        string? NewDescription,
-        Guid? NewPictureIntentId,
-        PlaylistVisibility? NewVisibility = null)
-        : ICommand<ErrorOr<PlayListApplicationResponse>>;
-
-    public class UpdatePlayListCommandHandler(
-        IEventBus eventBus,
-        IDatabase database,
-        UploadIntentValidator uploadIntentValidator,
-        ILogger<UpdatePlayListCommandHandler> logger,
-        ApplicationStorageConfiguration storageConfiguration,
-        PlayListConfiguration playListConfiguration,
-        UploadIntentConfiguration uploadIntentConfiguration)
-        : ICommandHandler<UpdatePlayListCommand, ErrorOr<PlayListApplicationResponse>>
+    public async ValueTask<ErrorOr<PlayListApplicationResponse>> Handle(UpdatePlayListCommand request, CancellationToken cancellationToken)
     {
-        public async ValueTask<ErrorOr<PlayListApplicationResponse>> Handle(UpdatePlayListCommand request, CancellationToken cancellationToken)
+        var found = await database.PlayLists.FindOwnedAsync(request.PlayListId, request.UserId, cancellationToken);
+        if (found.IsError)
+            return found.Errors;
+
+        var playList = found.Value;
+
+        if (!string.IsNullOrWhiteSpace(request.NewName))
         {
-            var playListEntity = await database.PlayLists.SingleOrDefaultAsync(pl => pl.Id == request.PlayListId, cancellationToken);
-            if (playListEntity == null)
-            {
-                logger.LogInformation("Playlist {PlayListId} not found", request.PlayListId);
-                return Error.NotFound();
-            }
-
-            if (playListEntity.UserId != request.UserId)
-            {
-                logger.LogWarning("User {UserId} is not the owner of playlist {PlayListId}", request.UserId, request.PlayListId);
-                return Error.Unauthorized();
-            }
-
-            if (!string.IsNullOrWhiteSpace(request.NewName))
-            {
-                playListEntity.Name = request.NewName;
-                playListEntity.NormalizedName = request.NewName.Trim().ToUpperInvariant();
-            }
-
-            if (!string.IsNullOrWhiteSpace(request.NewDescription))
-            {
-                playListEntity.Description = request.NewDescription;
-            }
-
-            if (request.NewVisibility.HasValue)
-            {
-                playListEntity.Visibility = request.NewVisibility.Value;
-            }
-
-            UploadIntent? pictureIntent = null;
-            string? finalPictureKey = null;
-
-            if (request.NewPictureIntentId.HasValue)
-            {
-                var validation = await uploadIntentValidator.ValidateAndLoadAsync(
-                    uploadIntentConfiguration,
-                    request.NewPictureIntentId.Value, request.UserId, cancellationToken);
-                if (validation.IsError)
-                    return validation.Errors;
-
-                pictureIntent = validation.Value;
-                playListEntity.Pictures = new PlayListPictures
-                {
-                    OriginalName = pictureIntent.ObjectName,
-                    SmallName = pictureIntent.ObjectName,
-                    MediumName = pictureIntent.ObjectName,
-                    LargeName = pictureIntent.ObjectName
-                };
-                finalPictureKey = playListConfiguration.Routes.BuildOriginalPicturePath(request.UserId, pictureIntent.ObjectName);
-            }
-
-            if (pictureIntent != null && finalPictureKey != null)
-            {
-                var publishResult = await PublishUpdatePlayListPictureSourceEventAsync(
-                    playListEntity.Id, pictureIntent, finalPictureKey, cancellationToken);
-                if (publishResult.IsError)
-                    return publishResult.Errors;
-            }
-
-            try
-            {
-                await database.SaveChangesAsync(cancellationToken);
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to update playlist {PlayListId}", playListEntity.Id);
-                return Error.Failure(description: $"Failed to update playlist {playListEntity.Id}");
-            }
-
-            var coverTrackIds = await database.PlayListHasTracks
-                .AsNoTracking()
-                .Where(plt => plt.PlayListId == playListEntity.Id)
-                .OrderBy(plt => plt.Position)
-                .Take(PlayListApplicationResponse.CoverTrackCount)
-                .Select(plt => plt.TrackId)
-                .ToListAsync(cancellationToken);
-
-            logger.LogInformation("Updated playlist {PlayListId}", playListEntity.Id);
-            return PlayListApplicationResponse.FromEntity(playListEntity, coverTrackIds);
+            playList.Name = request.NewName.Trim();
+            playList.NormalizedName = TextNormalizer.Normalize(request.NewName);
         }
 
-        private async Task<ErrorOr<Success>> PublishUpdatePlayListPictureSourceEventAsync(
-            Guid playListId,
-            UploadIntent pictureIntent,
-            string finalPictureKey,
-            CancellationToken cancellationToken)
+        // null means "unchanged"; a blank description clears it.
+        if (request.NewDescription != null)
+            playList.Description = string.IsNullOrWhiteSpace(request.NewDescription) ? null : request.NewDescription.Trim();
+
+        if (request.NewVisibility is { } visibility)
+            playList.Visibility = visibility;
+
+        if (request.NewPictureIntentId is { } intentId)
         {
-            try
-            {
-                await eventBus.PublishAsync(
-                    new UpdatePlayListPictureSourceEvent(
-                        playListId,
-                        pictureIntent.Id,
-                        storageConfiguration.Bucket,
-                        pictureIntent.Key,
-                        finalPictureKey,
-                        new ImageSize(
-                            playListConfiguration.Routes.SmallPicturesPath,
-                            playListConfiguration.PicturesSizes.SmallPictureWidth,
-                            playListConfiguration.PicturesSizes.SmallPictureHeight),
-                        new ImageSize(
-                            playListConfiguration.Routes.MediumPicturesPath,
-                            playListConfiguration.PicturesSizes.MediumPictureWidth,
-                            playListConfiguration.PicturesSizes.MediumPictureHeight),
-                        new ImageSize(
-                            playListConfiguration.Routes.LargePicturesPath,
-                            playListConfiguration.PicturesSizes.LargePictureWidth,
-                            playListConfiguration.PicturesSizes.LargePictureHeight)),
-                    cancellationToken);
-                return new Success();
-            }
-            catch (Exception exception)
-            {
-                logger.LogError(exception, "Failed to publish update playlist picture source event for playlist {PlayListId}", playListId);
-                return Error.Failure(description: $"Failed to publish update playlist picture source event for playlist {playListId}");
-            }
+            var prepared = await PictureSourceChange.PrepareAsync(
+                uploadIntentValidator, intentId, request.UserId, UploadIntentPurpose.PlayListPicture, playListConfiguration, cancellationToken);
+            if (prepared.IsError)
+                return prepared.Errors;
+
+            var picture = prepared.Value;
+            playList.Pictures = picture.Pictures;
+
+            await eventBus.PublishAsync(
+                new UpdatePlayListPictureSourceEvent(
+                    playList.Id, picture.Intent.Id, picture.Intent.Bucket, picture.Intent.Key, picture.FinalKey, picture.Sizes),
+                cancellationToken);
         }
+
+        await database.SaveChangesAsync(cancellationToken);
+
+        logger.LogInformation("Updated playlist {PlayListId}", playList.Id);
+
+        return await database.PlayLists
+            .AsNoTracking()
+            .Where(p => p.Id == playList.Id)
+            .SelectResponse()
+            .SingleAsync(cancellationToken);
     }
 }

backend/Core/Musify.Application/Services/TrackStreamIssuer.cs

@@ -1,28 +1,20 @@
 using Musify.Application.Configuration;
 using Musify.Application.Contracts;
 using Musify.Application.Tracks.Responses;
-using Musify.Domain.Entities;
 
 namespace Musify.Application.Services;
 
+/// <summary>Builds the stream URL and signed ticket for a processed track. It never touches the database.</summary>
 public sealed class TrackStreamIssuer(
-    IDatabase database,
     IStreamTicketService ticketService,
     TrackConfiguration trackConfiguration,
     StreamGatewayConfiguration streamGatewayConfiguration,
     PlaybackConfiguration playbackConfiguration)
 {
-    public async Task<TrackStreamResponse> IssueAsync(
-        Guid trackId,
-        string audioFolderName,
-        long? userId,
-        CancellationToken cancellationToken)
+    public TrackStreamResponse Issue(string audioFolderName, long? userId, Guid? listenId)
     {
         var folderPath = trackConfiguration.Routes.BuildProcessedAudioPath(audioFolderName);
-        var keyPrefix = $"{folderPath}/";
-
-        var maxBytes = AnonymousFragmentBytes(userId);
-        var ticket = ticketService.IssueTicket(userId, keyPrefix, maxBytes);
+        var ticket = ticketService.IssueTicket(userId, $"{folderPath}/", AnonymousFragmentBytes(userId));
 
         var manifestUrl = string.Join('/',
             streamGatewayConfiguration.PublicBaseUrl.TrimEnd('/'),
@@ -30,19 +22,6 @@ public sealed class TrackStreamIssuer(
             folderPath,
             streamGatewayConfiguration.AudioFileName);
 
-        Guid? listenId = null;
-        if (userId != null)
-        {
-            var newListeningHistory = new ListeningHistory
-            {
-                UserId = userId.Value,
-                TrackId = trackId,
-            };
-            await database.ListeningHistories.AddAsync(newListeningHistory, cancellationToken);
-            await database.SaveChangesAsync(cancellationToken);
-            listenId = newListeningHistory.Id;
-        }
-
         return new TrackStreamResponse(manifestUrl, ticket.Token, ticket.ExpiresInSeconds, listenId);
     }