ging/social_stream

# When a new {SocialStream::Models::Subject subject} is created, a initial set
# of relations is created for him. Afterwards, the {SocialStream::Models::Subject subject}
# can customize them and adapt them to his own preferences.
#
# Default relations are defined at config/initializers/social_stream.rb
#
class Relation::Custom < Relation
  # This is weird. We must call #inspect before has_ancestry for Relation::Custom
  # to recognize STI
  inspect
  has_ancestry

  belongs_to :actor

  validates_presence_of :name, :actor_id
  validates_uniqueness_of :name, :scope => :actor_id

  scope :actor, lambda { |a|
    where(:actor_id => Actor.normalize_id(a))
  }

  before_create :initialize_sender_type

  class << self
    def defaults_for(actor)
      subject_type = actor.subject.class.to_s.underscore

      cfg_rels = SocialStream.custom_relations.with_indifferent_access[subject_type]

      if cfg_rels.nil?
        raise "Undefined relations for subject type #{ subject_type }. Please, add an entry to config/initializers/social_stream.rb"
      end

      rels = {}

      cfg_rels.each_pair do |name, cfg_rel|
        rels[name] =
          create! :actor =>         actor,
                  :name  =>         cfg_rel[:name],
                  :receiver_type => cfg_rel[:receiver_type]

        if (ps = cfg_rel[:permissions]).present?
          ps.each do |p| 
            p.push(nil) if p.size == 1

            rels[name].permissions << 
              Permission.find_or_create_by_action_and_object(*p)
          end 
        end
      end

      # Parent, relations must be set after creation
      # FIXME: Can fix with ruby 1.9 and ordered hashes
      cfg_rels.each_pair do |name, cfg_rel|
        rels[name].update_attribute(:parent, rels[cfg_rel['parent']])
      end

      rels.values
    end
  end

  # The subject who defined of this relation
  def subject
    actor.subject
  end

  def available_permissions
    Permission.available(subject)
  end

  private

  # Before create callback
  def initialize_sender_type
    return if actor.blank?

    self.sender_type = actor.subject_type
  end
end