helper or controller method?

breadcrumb setter

def set_breadcrumbs_session(current, breadcrumbs) 
    if current.root?
      breadcrumbs = [current.id]
    else
      parent_ids = []
      current.parents.each{|c| parent_ids << c.id}
      if parent_ids.include?(breadcrumbs.last)
        breadcrumbs << current.id
      else
        if breadcrumbs.include?(current.id)
          while breadcrumbs.last != current.id do
            breadcrumbs.pop
          end
        else
          breadcrumbs = nil
        end
      end      
    end    
    breadcrumbs
  end