require 'sfn'

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

      # Validate attributes within Parameter blocks
      ALLOWED_PARAMETER_ATTRIBUTES = %w(
        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