require "sfn"

module Sfn
  module Utils
    # Helper for scrubbing stack parameters
    module StackParameterScrubber

      # Validate attributes within Parameter blocks
      ALLOWED_PARAMETER_ATTRIBUTES = [
        "Type", "Default", "NoEcho", "AllowedValues", "AllowedPattern",
        "MaxLength", "MinLength", "MaxValue", "MinValue", "Description",
        "ConstraintDescription",
      ]

      # Clean the parameters of the template
      #
      # @param template [Hash]
      # @return [Hash] template
      def parameter_scrub!(template)
        parameters = template["Parameters"]
        if parameters
          parameters.each do |name, options|
            options.delete_if do |attribute, value|
              !ALLOWED_PARAMETER_ATTRIBUTES.include?(attribute)
            end
          end
          template["Parameters"] = parameters
        end
        template
      end
    end
  end
end