/// <summary>
/// Gets the generic validated type appropriate for the specified <paramref name="builderType"/>.
/// </summary>
/// <remarks>
/// <para>
/// A builder type is one which implements the interface <see cref="IBuildsValidator{TValidated}"/>.
/// This method gets the value of the generic type parameter used for that interface.
/// </para>
/// <para>
/// In order to be used with this method, the <paramref name="builderType"/> must implement
/// <see cref="IBuildsValidator{TValidated}"/> for precisely one generic type.
/// If the builder type implements the interface more than once then this method will be unable to return
/// a definitive result and will throw an exception.
/// </para>
/// </remarks>
/// <param name="builderType">A type that indicates a validator builder.</param>
/// <returns>The <see cref="Type"/> for which the specified builder type validates.</returns>
public Type GetValidatedType(Type builderType)
{
if (builderType is null)
{
throw new ArgumentNullException(nameof(builderType));
}
var validatedTypes = builderType
.GetTypeInfo()
.ImplementedInterfaces
.Where(isBuilderInterface)
.Select(x => x.GetTypeInfo().GenericTypeArguments.First())
.ToList();
if (validatedTypes.Count == 1)
{
return(validatedTypes.Single());
}
if (!validatedTypes.Any())
{
var message = String.Format(ExceptionMessages.GetExceptionMessage("BuilderTypeDoesNotImplementBuilderInterface"),
builderType.FullName,
builderInterfaceName);
throw new ArgumentException(message, nameof(builderType));
}
else
{
var message = String.Format(ExceptionMessages.GetExceptionMessage("BuilderTypeImplementsTooManyBuilderInterfaces"),
builderType.FullName,
builderInterfaceName);
throw new ArgumentException(message, nameof(builderType));
}
}
