module Puppet::Parser::Functions
   newfunction(:nagios_rdiff_backup_config) do |args|
      module NagiosCommonTop
         return if lookupvar('config_path').empty?

         hostname = lookupvar('long_name')

         #generate nagios rdiff backup monitoring config file
         service_definition = '# Do not modify this file by hand; it is automatically generated by Puppet.
         # Any changes you make here will be over-written by Puppet on its next run.
         '

         nagios_host = `grep 'host_name #{hostname}' #{lookupvar('config_path')}../hosts/hosts.cfg | grep -v ^#`
      end
      include NagiosCommonTop

      if nagios_host.empty? then
         service_definition += "
            # This host is not currently being monitored by nagios
            # To enable this service monitor, add the host to
            # #{lookupvar('config_path')}../hosts/hosts.cfg
         "
      else
         service_definition += "
            define service {
             use generic-service
             hosts "+hostname+"
             service_description New backed-up files
             check_command check_rdiff_backup_age!2
            }
         "
      end

      service_definition = service_definition.gsub(/^\t+/, '') #remove ugly leading tabs
      service_definition = service_definition.gsub(/^ /, "\t") #replace leading spaces with tabs

      original_config = ''
      begin
         on_disk = File.open(lookupvar('config_path') + hostname + '_rdiff_backup.cfg', File::RDONLY)
         original_config = on_disk.readlines.join
      rescue
         #we don't care if it fails, because "original_file" will already be empty
      end

      if original_config != service_definition
         File.open(lookupvar('config_path') + hostname + '_rdiff_backup.cfg', 'w') do |fd|
            fd.puts service_definition
         end
         #we won't check for error handling here, because there's nothing we can do about it if it fails
      end

   end
end