Introduced Commentable

app/controllers/likes_controller.rb

@@ -62,7 +62,7 @@ class LikesController < ApplicationController
       current_user.find_visible_post_by_id(params[:post_id])
     else
       comment = Comment.find(params[:comment_id])
-      comment = nil unless current_user.find_visible_post_by_id(comment.post_id)
+      comment = nil unless current_user.find_visible_post_by_id(comment.commentable_id)
       comment
     end
   end

app/models/comment.rb

@@ -23,7 +23,8 @@ class Comment < ActiveRecord::Base
   xml_attr :text
   xml_attr :diaspora_handle
 
-  belongs_to :post
+  belongs_to :commentable, :touch => true, :polymorphic => true
+  alias_attribute :post, :commentable
   belongs_to :author, :class_name => 'Person'
 
   validates :text, :presence => true, :length => { :maximum => 2500 }

app/models/post.rb

@@ -10,14 +10,13 @@ class Post < ActiveRecord::Base
   include Diaspora::Guid
 
   include Diaspora::Likeable
+  include Diaspora::Commentable
 
   xml_attr :diaspora_handle
   xml_attr :provider_display_name
   xml_attr :public
   xml_attr :created_at
 
-  has_many :comments, :order => 'created_at', :dependent => :destroy
-
   has_many :aspect_visibilities
   has_many :aspects, :through => :aspect_visibilities
 

app/views/comments/_comment.html.haml

@@ -5,7 +5,7 @@
 %li.comment.posted{:id => comment.guid, :class => ("hidden" if(defined? hidden))}
   - if current_user && (current_user.owns?(comment) || current_user.owns?(post))
     .right.controls
-      = link_to image_tag('deletelabel.png'), post_comment_path(comment.post_id, comment), :class => "delete comment_delete", :title => t('delete')
+      = link_to image_tag('deletelabel.png'), post_comment_path(comment.commentable_id, comment), :class => "delete comment_delete", :title => t('delete')
   = person_image_link(comment.author, :size => :thumb_small)
   .content
     %span.from

db/migrate/20110823212706_comment_anything.rb

@@ -0,0 +1,18 @@
+class CommentAnything < ActiveRecord::Migration
+  def self.up
+    remove_foreign_key :comments, :posts
+    remove_index :comments, :post_id
+    change_table :comments do |t|
+      t.rename :post_id, :commentable_id
+      t.string :commentable_type, :default => 'Post', :null => false
+    end
+  end
+
+  def self.down
+    rename_column :comments, :commentable_id, :post_id
+    add_foreign_key :comments, :posts
+    add_index :comments, :post_id
+
+    remove_column :comments, :commentable_type
+  end
+end

lib/diaspora/commentable.rb

@@ -0,0 +1,25 @@
+#   Copyright (c) 2010, Diaspora Inc.  This file is
+#   licensed under the Affero General Public License version 3 or later.  See
+#   the COPYRIGHT file.
+
+module Diaspora
+  module Commentable
+    def self.included(model)
+      model.instance_eval do
+        has_many :comments, :as => :commentable, :order => 'created_at', :dependent => :destroy
+      end
+    end
+
+    # @return [Array<Comment>]
+    def last_three_comments
+      self.comments.order('created_at DESC').limit(3).includes(:author => :profile).reverse
+    end
+  end
+
+  # @return [Integer]
+  def update_comments_counter
+    self.class.where(:id => self.id).
+      update_all(:comments_count => self.comments.count)
+  end
+
+end