/// <summary>
/// Adds a type to a <see cref="FilterCollection" /> if it doesn't already exist.
/// </summary>
/// <typeparam name="TType">The type of the t type.</typeparam>
/// <param name="col">The col.</param>
/// <param name="order">Filter order</param>
/// <returns>FilterCollection.</returns>
public static FilterCollection TryAdd <TType>(this FilterCollection col, int?order = null)
where TType : IFilterMetadata
{
var vt = typeof(TType);
if (col.All(t =>
{
// Yet more lameness, really should be able to do a simple test here...
return(t switch
{
TypeFilterAttribute tf => tf.ImplementationType != vt,
ServiceFilterAttribute sf => sf.ServiceType != vt,
FormatFilterAttribute ff => ff.GetType() != vt,
ResultFilterAttribute rs => rs.GetType() != vt,
ExceptionFilterAttribute ef => ef.GetType() != vt,
ActionFilterAttribute af => af.GetType() != vt,
_ => t.GetType() != vt
});
}
