resolve reshare root posts to the first one

app/models/reshare.rb

@@ -69,6 +69,15 @@ class Reshare < Post
     root.try(:nsfw)
   end
 
+  def absolute_root
+    current = self
+    while( current.is_a?(Reshare) )
+      current = current.root
+    end
+
+    current
+  end
+
   private
 
   def after_parse

app/presenters/post_presenter.rb

@@ -63,7 +63,7 @@ class PostPresenter
   end
 
   def root
-    PostPresenter.new(@post.root, current_user).as_json if @post.respond_to?(:root) && @post.root.present?
+    PostPresenter.new(@post.absolute_root, current_user).as_json if @post.respond_to?(:root) && @post.root.present?
   end
 
   def user_like
@@ -83,6 +83,7 @@ class PostPresenter
   def user_signed_in?
     @current_user.present?
   end
+
 end
 
 class PostInteractionPresenter

spec/models/reshare_spec.rb

@@ -81,6 +81,19 @@ describe Reshare do
     end
   end
 
+  describe '#absolute_root' do
+    before do
+      @sm = Factory(:status_message, :author => alice.person, :public => true)
+      rs1 = Factory(:reshare, :root=>@sm)
+      rs2 = Factory(:reshare, :root=>rs1)
+      @rs3 = Factory(:reshare, :root=>rs2)
+    end
+
+    it 'resolves root posts to the top level' do
+      @rs3.absolute_root.should == @sm
+    end
+  end
+
   describe "XML" do
     before do
       @reshare = Factory(:reshare)