require 'nori'

# Class who handles Gateway post notification XML
class PostNotification

  # This method parse the Xml sent by Gateway when notify a change in a transaction.
  #
  # @param request [String] XML received in the Gateway POST request.
  # @return [Hash<Symbol, String>] A hash collection containing the XML data parsed.
  def self.ParseNotification(xml)

    nori = Nori.new(:convert_tags_to => lambda { |tag| PostNotification.to_underscore(tag).to_sym })
    xml_hash  = nori.parse(CGI::unescapeHTML(xml))

    return xml_hash
  end

  # Converts a string in Camel Case format to lower case with underscore.
  #
  # @param Example: 'StatusNotification' outputs 'status_notification'
  # @returns [String] lower case string separated with underscore
  def self.to_underscore(camel_case_string)
    return camel_case_string.gsub(/::/, '/').
        gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
        gsub(/([a-z\d])([A-Z])/,'\1_\2').
        tr("-", "_").
        downcase
  end
end