from plone import api
from plone.app.layout.viewlets.common import ViewletBase
from plone.memoize.view import memoize_contextless


class Viewlet(ViewletBase):
    """Check if the on screen help toggle button should be displayed
    in the portal header
    """

    def update(self):
        """We do not need the attributes set by the default update method"""
        return

    @memoize_contextless
    def available(self):
        """This will be available if the site has bubbles enabled"""
        portal = api.portal.get()
        view = api.content.get_view("on-screen-help", portal, self.request)
        return bool(view.bubbles)
