Musify/backend/Core/Musify.Infrastructure/Persistence/Database.cs

using ErrorOr;
using MassTransit;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Storage;
using Musify.Application.Contracts;
using Musify.Domain.Entities;
using Musify.Domain.ValueObjects;
using Musify.Infrastructure.Configuration;
using Musify.Infrastructure.MassTransit.Sagas;
using Npgsql;

namespace Musify.Infrastructure.Persistence;

public class Database(DatabaseConfiguration configuration)
    : DbContext, Musify.Application.Contracts.IDatabase
{
    private static readonly AuditableEntityInterceptor AuditInterceptor = new();

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder
            .UseNpgsql(configuration.ConnectionString, o => o.MapEnum<Genre>("genre"))
            .AddInterceptors(AuditInterceptor);
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        modelBuilder.AddInboxStateEntity();
        modelBuilder.AddOutboxMessageEntity();
        modelBuilder.AddOutboxStateEntity();

        var trackProcessing = modelBuilder.Entity<TrackProcessingState>();
        trackProcessing.HasKey(state => state.CorrelationId);
        trackProcessing.Property(state => state.CorrelationId).ValueGeneratedNever();
        trackProcessing.Property(state => state.CurrentState).HasMaxLength(64);

        modelBuilder.Entity<Track>()
            .OwnsOne(track => track.Pictures, pictures =>
            {
                pictures.Property(p => p.OriginalName).HasColumnName("OriginalPictureName").HasMaxLength(64);
                pictures.Property(p => p.SmallName).HasColumnName("SmallPictureName").HasMaxLength(64);
                pictures.Property(p => p.MediumName).HasColumnName("MediumPictureName").HasMaxLength(64);
                pictures.Property(p => p.LargeName).HasColumnName("LargePictureName").HasMaxLength(64);
                pictures.Property(p => p.ProcessingStatus).HasColumnName("PicturesProcessingStatus");
            });
        modelBuilder.Entity<Track>().Navigation(track => track.Pictures).IsRequired();

        modelBuilder.Entity<Track>()
            .OwnsOne(track => track.Audio, audio =>
            {
                audio.Property(a => a.OriginalName).HasColumnName("OriginalAudioName").HasMaxLength(64);
                audio.Property(a => a.FolderName).HasColumnName("AudioFolderName").HasMaxLength(64);
                audio.Property(a => a.TranscodeStatus).HasColumnName("AudioTranscodeProcessingStatus");
            });
        modelBuilder.Entity<Track>().Navigation(track => track.Audio).IsRequired();

        modelBuilder.Entity<Track>()
            .HasOne(track => track.Owner)
            .WithMany()
            .HasForeignKey(track => track.OwnerUserId)
            .OnDelete(DeleteBehavior.Restrict);

        modelBuilder.Entity<PlayList>()
            .Property(playList => playList.Visibility)
            .HasDefaultValue(PlayListVisibility.Private);

        modelBuilder.Entity<PlayList>()
            .OwnsOne(playList => playList.Pictures, pictures =>
            {
                pictures.Property(p => p.OriginalName).HasColumnName("OriginalPictureName").HasMaxLength(64).IsRequired(false);
                pictures.Property(p => p.SmallName).HasColumnName("SmallPictureName").HasMaxLength(64).IsRequired(false);
                pictures.Property(p => p.MediumName).HasColumnName("MediumPictureName").HasMaxLength(64).IsRequired(false);
                pictures.Property(p => p.LargeName).HasColumnName("LargePictureName").HasMaxLength(64).IsRequired(false);
            });
        modelBuilder.Entity<PlayList>().Navigation(playList => playList.Pictures).IsRequired(false);

        modelBuilder.Entity<Album>()
            .OwnsOne(album => album.Pictures, pictures =>
            {
                pictures.Property(p => p.OriginalName).HasColumnName("OriginalPictureName").HasMaxLength(64);
                pictures.Property(p => p.SmallName).HasColumnName("SmallPictureName").HasMaxLength(64).IsRequired(false);
                pictures.Property(p => p.MediumName).HasColumnName("MediumPictureName").HasMaxLength(64).IsRequired(false);
                pictures.Property(p => p.LargeName).HasColumnName("LargePictureName").HasMaxLength(64).IsRequired(false);
            });
        modelBuilder.Entity<Album>().Navigation(album => album.Pictures).IsRequired(false);

        modelBuilder.Entity<Album>()
            .HasOne(album => album.Owner)
            .WithMany()
            .HasForeignKey(album => album.OwnerUserId)
            .OnDelete(DeleteBehavior.Restrict);

        modelBuilder.Entity<AlbumHasTrack>()
            .HasOne(albumTrack => albumTrack.Album)
            .WithMany(album => album.AlbumTracks)
            .HasForeignKey(albumTrack => albumTrack.AlbumId)
            .OnDelete(DeleteBehavior.Cascade);

        modelBuilder.Entity<AlbumHasTrack>()
            .HasOne(albumTrack => albumTrack.Track)
            .WithMany(track => track.AlbumTracks)
            .HasForeignKey(albumTrack => albumTrack.TrackId)
            .OnDelete(DeleteBehavior.Cascade);

        modelBuilder.Entity<AlbumHasTrack>()
            .HasIndex(albumTrack => new { albumTrack.AlbumId, albumTrack.TrackId })
            .IsUnique();

        modelBuilder.Entity<PlayListHasTrack>()
            .HasIndex(playListTrack => new { playListTrack.PlayListId, playListTrack.TrackId })
            .IsUnique();

        modelBuilder.Entity<Mix>()
            .HasIndex(mix => new { mix.UserId, mix.Position });

        modelBuilder.Entity<MixItem>()
            .HasOne(item => item.Mix)
            .WithMany(mix => mix.Items)
            .HasForeignKey(item => item.MixId)
            .OnDelete(DeleteBehavior.Cascade);

        modelBuilder.Entity<MixItem>()
            .HasOne(item => item.Track)
            .WithMany()
            .HasForeignKey(item => item.TrackId)
            .OnDelete(DeleteBehavior.Cascade);

        modelBuilder.Entity<MixItem>()
            .HasIndex(item => new { item.MixId, item.Position });

        modelBuilder.Entity<TrackLike>()
            .HasIndex(like => new { like.UserId, like.TrackId })
            .IsUnique();

        modelBuilder.Entity<TrackTag>()
            .HasOne(trackTag => trackTag.Track)
            .WithMany(track => track.Tags)
            .HasForeignKey(trackTag => trackTag.TrackId)
            .OnDelete(DeleteBehavior.Cascade);

        modelBuilder.Entity<TrackTag>()
            .HasIndex(trackTag => new { trackTag.TrackId, trackTag.Tag })
            .IsUnique();

        modelBuilder.Entity<UserFollow>()
            .HasOne(follow => follow.Follower)
            .WithMany()
            .HasForeignKey(follow => follow.FollowerId)
            .OnDelete(DeleteBehavior.Restrict);

        modelBuilder.Entity<UserFollow>()
            .HasOne(follow => follow.Followed)
            .WithMany()
            .HasForeignKey(follow => follow.FollowedId)
            .OnDelete(DeleteBehavior.Restrict);

        modelBuilder.Entity<UserFollow>()
            .HasIndex(follow => new { follow.FollowerId, follow.FollowedId })
            .IsUnique();

        var playListProcessing = modelBuilder.Entity<PlayListProcessingState>();
        playListProcessing.HasKey(state => state.CorrelationId);
        playListProcessing.Property(state => state.CorrelationId).ValueGeneratedNever();
        playListProcessing.Property(state => state.CurrentState).HasMaxLength(64);

        var albumProcessing = modelBuilder.Entity<AlbumProcessingState>();
        albumProcessing.HasKey(state => state.CorrelationId);
        albumProcessing.Property(state => state.CorrelationId).ValueGeneratedNever();
        albumProcessing.Property(state => state.CurrentState).HasMaxLength(64);
    }

    public DbSet<User> Users => Set<User>();

    public DbSet<Track> Tracks => Set<Track>();

    public DbSet<PlayList> PlayLists => Set<PlayList>();

    public DbSet<Album> Albums => Set<Album>();

    public DbSet<AlbumHasTrack> AlbumHasTracks => Set<AlbumHasTrack>();

    public DbSet<PlayListHasTrack> PlayListHasTracks => Set<PlayListHasTrack>();

    public DbSet<Mix> Mixes => Set<Mix>();

    public DbSet<MixItem> MixItems => Set<MixItem>();

    public DbSet<UploadIntent> UploadIntents => Set<UploadIntent>();

    public DbSet<ListeningHistory> ListeningHistories => Set<ListeningHistory>();

    public DbSet<TrackLike> TrackLikes => Set<TrackLike>();

    public DbSet<TrackTag> TrackTags => Set<TrackTag>();

    public DbSet<UserFollow> UserFollows => Set<UserFollow>();

    public async Task<IDatabaseTransaction> BeginTransactionAsync(System.Data.IsolationLevel isolationLevel, CancellationToken cancellationToken)
    {
        var transaction = await Database.BeginTransactionAsync(isolationLevel, cancellationToken);
        return new DatabaseTransaction(transaction);
    }

    public async Task<ErrorOr<Success>> TrySaveChangesAsync(Error onUniqueViolation, CancellationToken cancellationToken)
    {
        try
        {
            await SaveChangesAsync(cancellationToken);
            return Result.Success;
        }
        catch (DbUpdateException exception) when (exception.InnerException is PostgresException { SqlState: PostgresErrorCodes.UniqueViolation })
        {
            return onUniqueViolation;
        }
    }

    private sealed class DatabaseTransaction(IDbContextTransaction inner) : IDatabaseTransaction
    {
        public Task CommitAsync(CancellationToken cancellationToken) =>
            inner.CommitAsync(cancellationToken);

        public ValueTask DisposeAsync() => inner.DisposeAsync();
    }
}