module WelcomeHelper
  def manage_samples_link
    manage_samples_link_for(current_user, [:submitter, :reviewer, :admin])
  end

  def manage_samples_link(user, acceptable_roles)
    has_acceptable_role = acceptable_roles.inject(false) { | sum, each |
      sum ||= user.role?(each)
    }

    has_acceptable_role ? nil : link_to "Manage Samples", manage_samples_path
  end
end