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

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Diagnostics;
using Musify.Domain.Abstractions;

namespace Musify.Infrastructure.Persistence;

public sealed class AuditableEntityInterceptor : SaveChangesInterceptor
{
    public override InterceptionResult<int> SavingChanges(DbContextEventData eventData, InterceptionResult<int> result)
    {
        ApplyTimestamps(eventData.Context);
        return base.SavingChanges(eventData, result);
    }

    public override ValueTask<InterceptionResult<int>> SavingChangesAsync(
        DbContextEventData eventData, InterceptionResult<int> result, CancellationToken cancellationToken = default)
    {
        ApplyTimestamps(eventData.Context);
        return base.SavingChangesAsync(eventData, result, cancellationToken);
    }

    private static void ApplyTimestamps(DbContext? context)
    {
        if (context == null)
            return;

        context.ChangeTracker.DetectChanges();

        var now = DateTime.UtcNow;

        foreach (var entry in context.ChangeTracker.Entries<IAuditable>())
        {
            if (entry.State == EntityState.Added)
            {
                entry.Entity.CreatedAt = now;
                entry.Entity.UpdatedAt = now;
            }
            else if (entry.State == EntityState.Modified)
            {
                entry.Property(nameof(IAuditable.UpdatedAt)).CurrentValue = now;
            }
        }
    }
}