implemented automatic database cleanup

src/HopFrame.Database/HopDbContextBase.cs

@@ -8,6 +8,8 @@ namespace HopFrame.Database;
 /// </summary>
 public abstract class HopDbContextBase : DbContext {
 
+    public static IList<Action<HopDbContextBase>> SaveHandlers = new List<Action<HopDbContextBase>>();
+
     public virtual DbSet<User> Users { get; set; }
     public virtual DbSet<Permission> Permissions { get; set; }
     public virtual DbSet<Token> Tokens { get; set; }
@@ -36,4 +38,36 @@ public abstract class HopDbContextBase : DbContext {
             .WithOne(t => t.Token)
             .OnDelete(DeleteBehavior.Cascade);
     }
+
+    private void OnSaving() {
+        var orphanedPermissions = Permissions
+            .Where(p => p.UserId == null && p.GroupName == null && p.TokenId == null)
+            .ToList();
+
+        foreach (var handler in SaveHandlers) {
+            handler.Invoke(this);
+        }
+    
+        Permissions.RemoveRange(orphanedPermissions);
+    }
+
+    public override int SaveChanges() {
+        OnSaving();
+        return base.SaveChanges();
+    }
+
+    public override int SaveChanges(bool acceptAllChangesOnSuccess) {
+        OnSaving();
+        return base.SaveChanges(acceptAllChangesOnSuccess);
+    }
+
+    public override Task<int> SaveChangesAsync(CancellationToken cancellationToken = new CancellationToken()) {
+        OnSaving();
+        return base.SaveChangesAsync(cancellationToken);
+    }
+
+    public override Task<int> SaveChangesAsync(bool acceptAllChangesOnSuccess, CancellationToken cancellationToken = new CancellationToken()) {
+        OnSaving();
+        return base.SaveChangesAsync(acceptAllChangesOnSuccess, cancellationToken);
+    }
 }

src/HopFrame.Database/Models/Permission.cs

@@ -18,12 +18,18 @@ public class Permission {
     [ForeignKey("UserId"), JsonIgnore]
     public virtual User User { get; set; }
 
+    public Guid? UserId { get; set; }
+
     [ForeignKey("GroupName"), JsonIgnore]
     public virtual PermissionGroup Group { get; set; }
+
+    [MaxLength(255)]
+    public string GroupName { get; set; }
     
     [ForeignKey("TokenId"), JsonIgnore]
     public virtual Token Token { get; set; }
     
+    public Guid? TokenId { get; set; }
 }
 
 public interface IPermissionOwner;