acts_as_commentable_with_threading.rb

require 'active_record'
require 'awesome_nested_set'
ActiveRecord::Base.class_eval do
  include CollectiveIdea::Acts::NestedSet
end

#
unless ActiveRecord::Base.respond_to?(:acts_as_nested_set)
  ActiveRecord::Base.send(:include, CollectiveIdea::Acts::NestedSet::Base)
end

# ActsAsCommentableWithThreading
module Acts #:nodoc:
  module CommentableWithThreading #:nodoc:
    extend ActiveSupport::Concern

    module ClassMethods
      def acts_as_commentable
        has_many :comment_threads, class_name: 'Comment', as: :commentable
        before_destroy { |record| record.root_comments.destroy_all }
        include Acts::CommentableWithThreading::LocalInstanceMethods
        extend Acts::CommentableWithThreading::SingletonMethods
      end
    end

    # This module contains class methods
    module SingletonMethods
      # Helper method to lookup for comments for a given object.
      # This method is equivalent to obj.comments.
      def find_comments_for(obj)
        Comment.where(commentable_id: obj.id,
                      commentable_type: obj.class.base_class.name)
          .order('created_at DESC')
      end

      # Helper class method to lookup comments for
      # the mixin commentable type written by a given user.
      # This method is NOT equivalent to Comment.find_comments_for_user
      def find_comments_by_user(user)
        commentable = base_class.name.to_s
        Comment.where(user_id: user.id, commentable_type: commentable)
          .order('created_at DESC')
      end
    end

    module LocalInstanceMethods
      # Helper method to display only root threads, no children/replies
      def root_comments
        comment_threads.where(parent_id: nil)
      end

      # Helper method to sort comments by date
      def comments_ordered_by_submitted
        Comment.where(commentable_id: id, commentable_type: self.class.name)
          .order('created_at DESC')
      end

      # Helper method that defaults the submitted time.
      def add_comment(comment)
        comments << comment
      end
    end
  end
end

ActiveRecord::Base.send(:include, Acts::CommentableWithThreading)