require 'puppet/util/queue'
require 'stomp'
require 'uri'

# Implements the Ruby Stomp client as a queue type within the
# Puppet::Indirector::Queue::Client registry, for use with the <tt>:queue</tt>
# indirection terminus type.
#
# Looks to <tt>Puppet[:queue_source]</tt> for the sole argument to the
# underlying Stomp::Client constructor; consequently, for this client to work,
# <tt>Puppet[:queue_source]</tt> must use the Stomp::Client URL-like syntax
# for identifying the Stomp message broker: <em>login:pass@host.port</em>
class Puppet::Util::Queue::Stomp
  attr_accessor :stomp_client

  def initialize
    begin
      uri = URI.parse(Puppet[:queue_source])
    rescue => detail
      raise ArgumentError, "Could not create Stomp client instance - queue source #{Puppet[:queue_source]} is invalid: #{detail}", detail.backtrace
    end
    unless uri.scheme == "stomp"
      raise ArgumentError, "Could not create Stomp client instance - queue source #{Puppet[:queue_source]} is not a Stomp URL: #{detail}"
    end

    begin
      self.stomp_client = Stomp::Client.new(uri.user, uri.password, uri.host, uri.port, true)
    rescue => detail
      raise ArgumentError, "Could not create Stomp client instance with queue source #{Puppet[:queue_source]}: got internal Stomp client error #{detail}", detail.backtrace
    end

    # Identify the supported method for sending messages.
    @method =
      case
      when stomp_client.respond_to?(:publish)
        :publish
      when stomp_client.respond_to?(:send)
        :send
      else
        raise ArgumentError, "STOMP client does not respond to either publish or send"
      end
  end

  def publish_message(target, msg)
    stomp_client.__send__(@method, stompify_target(target), msg, :persistent => true)
  end

  def subscribe(target)
    stomp_client.subscribe(stompify_target(target), :ack => :client) do |stomp_message|
      yield(stomp_message.body)
      stomp_client.acknowledge(stomp_message)
    end
  end

  def stompify_target(target)
    '/queue/' + target.to_s
  end

  Puppet::Util::Queue.register_queue_type(self, :stomp)
end