from .models import PremiumEntitlement


def has_lifetime_premium(user):
    """Return whether a user may access Lifetime Premium content."""
    if not getattr(user, "is_authenticated", False):
        return False
    if user.is_staff or user.is_superuser:
        return True
    return PremiumEntitlement.objects.filter(
        user=user,
        revoked_at__isnull=True,
    ).exists()


def can_access_exam(user, exam_set):
    return (
        exam_set.access_level == exam_set.ACCESS_FREE
        or has_lifetime_premium(user)
    )