# encoding: utf-8

require 'active_support/core_ext/class/attribute'
require 'virtus'

module Punchblock
  class RayoNode
    include Virtus

    @@registrations = {}

    class_attribute :registered_ns, :registered_name

    attribute :target_call_id
    attribute :target_mixer_name
    attribute :component_id
    attribute :domain
    attribute :transport

    attr_accessor :connection, :client, :original_component

    # Register a new stanza class to a name and/or namespace
    #
    # This registers a namespace that is used when looking
    # up the class name of the object to instantiate when a new
    # stanza is received
    #
    # @param [#to_s] name the name of the node
    # @param [String, nil] ns the namespace the node belongs to
    def self.register(name, ns = nil)
      self.registered_name = name.to_s
      self.registered_ns = ns.is_a?(Symbol) ? RAYO_NAMESPACES[ns] : ns
      @@registrations[[self.registered_name, self.registered_ns]] = self
    end

    # Find the class to use given the name and namespace of a stanza
    #
    # @param [#to_s] name the name to lookup
    # @param [String, nil] xmlns the namespace the node belongs to
    # @return [Class, nil] the class appropriate for the name/ns combination
    def self.class_from_registration(name, ns = nil)
      @@registrations[[name.to_s, ns]]
    end

    # Import an XML::Node to the appropriate class
    #
    # Looks up the class the node should be then creates it based on the
    # elements of the XML::Node
    # @param [XML::Node] node the node to import
    # @return the appropriate object based on the node name and namespace
    def self.from_xml(node, call_id = nil, component_id = nil)
      ns = (node.namespace.href if node.namespace)
      klass = class_from_registration(node.name, ns)
      if klass && klass != self
        klass.from_xml node, call_id, component_id
      else
        new.inherit node
      end.tap do |event|
        event.target_call_id = call_id
        event.component_id = component_id
      end
    end

    def inherit(xml_node)
      xml_node.attributes.each do |key, attr_node|
        setter_method = "#{key.gsub('-', '_')}="
        send setter_method, xml_node[key] if respond_to?(setter_method)
      end
      self
    end

    def inspect
      "#<#{self.class} #{to_hash.map { |k, v| "#{k}=#{v.inspect}" }.compact * ', '}>"
    end

    def ==(o)
      o.is_a?(self.class) && self.to_hash == o.to_hash
    end

    def to_hash
      get_attributes(&:public_reader?)
    end

    ##
    # @return [RayoNode] the original command issued that lead to this event
    #
    def source
      @source ||= client.find_component_by_id component_id if client && component_id
      @source ||= original_component
    end

    def rayo_attributes
      {}
    end

    def rayo_children(root)
    end

    def to_rayo(parent = nil)
      parent = parent.parent if parent.is_a?(Nokogiri::XML::Builder)
      Nokogiri::XML::Builder.with(parent) do |xml|
        xml.send(registered_name,
          {xmlns: registered_ns}.merge(rayo_attributes.delete_if { |k,v| v.nil? })) do |root|
          rayo_children root
        end
      end.doc.root
    end

    def to_xml
      to_rayo.to_xml
    end

    alias :to_s :inspect
  end
end