module MuckActivity # :nodoc:

  def self.included(base) # :nodoc:
    base.extend ActMethods
  end
  
  module ActMethods

    # +has_activities+ gives the class it is called on an activity feed and a method called
    # +add_activity+ that can add activities into a feed.  Retrieve activity feed items
    # via object.activities. ie @user.activities.
    def has_activities
      unless included_modules.include? InstanceMethods
        has_many :activity_feeds, :as => :ownable
        has_many :activities, :through => :activity_feeds, :order => 'created_at desc'
        include InstanceMethods
      end
    end
    
    # +acts_as_activity_source+ gives the class it is called on a method called
    # +add_activity+ that can add activities into a feed.
    def acts_as_activity_source
      unless included_modules.include? InstanceMethods
        include InstanceMethods
      end
    end

  end

  module InstanceMethods

    # +add_activity+ adds an activity to all activites feeds that belong to the objects found in feed_to.
    # * +feed_to+: an array of objects that have +has_activities+ declared on them.  The generated activity
    #   will be pushed into the feed of each of these objects.
    # * +source+: the object that peformed the activity ie a user or group
    # * +item+: an object that will be used to generated the entry in an activity feed
    # * +template+: name of an partial that will be used to generated the entry in the activity feed.  Place
    #   templates in /app/views/activity_templates
    # * +title+: optional title that can be used in the template
    # * +content+: option content that can be used in the template.  Useful for activities that might not have
    #    an item but instead might have a message or other text.
    # * +check_method+: method that will be called on each item in the feed_to array.  If the method evaluates
    #   to false the activity won't be added to the object's activity feed.  An example usage would be
    #   letting users configure which items they want to have in their activity feed.
    def add_activity(feed_to, source, item, template, title = '', content = '', check_method = nil)
      feed_to = [feed_to] unless feed_to.is_a?(Array)
      activity = Activity.create(:item => item, :source => source, :template => template, :title => title, :content => content)
      feed_to.each do |ft|
        if check_method
          ft.activities << activity if ft.send(check_method)
        else
          ft.activities << activity
        end
      end
    end
    
    # +status+ returns the first activity item from the user's activity feed that is a status update.
    # Used for displaying the last status update the user made
    def status
      self.activities.find(:first, :conditions => ['is_status_update = true'], :order => 'created_at DESC')
    end
    
    def can_view?(check_object)
      self == check_object
    end
  end

end