module Blather
class Stanza
class Presence

  # # Subscription Stanza
  #
  # [RFC 3921 Section 8 - Integration of Roster Items and Presence Subscriptions](http://xmpp.org/rfcs/rfc3921.html#rfc.section.8)
  #
  # Blather handles subscription request/response through this class. It
  # provides a set of helper methods to quickly transform the stanza into a
  # response.
  #
  # @handler :subscription
  class Subscription < Presence
    register :subscription, :subscription

    # Create a new Subscription stanza
    #
    # @param [Blather::JID, #to_s] to the JID to subscribe to
    # @param [Symbol, nil] type the subscription type
    def self.new(to = nil, type = nil)
      node = super()
      node.to = to
      node.type = type
      node
    end

    module InstanceMethods

      # Set the to value on the stanza
      #
      # @param [Blather::JID, #to_s] to a JID to subscribe to
      def to=(to)
        super JID.new(to).stripped
      end

      # Transform the stanza into an approve stanza
      # makes approving requests simple
      #
      # @example approve an incoming request
      #   subscription(:request?) { |s| write_to_stream s.approve! }
      # @return [self]
      def approve!
        self.type = :subscribed
        reply_if_needed!
      end

      # Transform the stanza into a refuse stanza
      # makes refusing requests simple
      #
      # @example refuse an incoming request
      #   subscription(:request?) { |s| write_to_stream s.refuse! }
      # @return [self]
      def refuse!
        self.type = :unsubscribed
        reply_if_needed!
      end

      # Transform the stanza into an unsubscribe stanza
      # makes unsubscribing simple
      #
      # @return [self]
      def unsubscribe!
        self.type = :unsubscribe
        reply_if_needed!
      end

      # Transform the stanza into a cancel stanza
      # makes canceling simple
      #
      # @return [self]
      def cancel!
        self.type = :unsubscribed
        reply_if_needed!
      end

      # Transform the stanza into a request stanza
      # makes requests simple
      #
      # @return [self]
      def request!
        self.type = :subscribe
        reply_if_needed!
      end

      # Check if the stanza is a request
      #
      # @return [true, false]
      def request?
        self.type == :subscribe
      end
    end

    include InstanceMethods

  end #Subscription

end #Presence
end #Stanza
end