# Definitions

Notification = collections.namedtuple('Notification', 'id body publish_date effective_date revised_dat')
NotificationWithPublishData = collections.namedtuple('NotificationWithPublishData', 'notification is_published')

# Entities

def unpublished_notifications(notifications_with_publish_data):
    """Given a list of notification, publish data tuples, return the list of notifications to publish."""
    return [notification_with_publish_data for notification_with_publish_data in notifications_with_publish_data
            if notifications_with_publish_data]


# Gateways
NotificationGateway

DbGateway

PublishGateway

# Use cases

def publish_new_notifications(context, date_range):
    """Given a date range, publish all non-published notifications from context.notification_gateway to
   context.wire_gateway. Set all notifications that are published to `published` on context.db_gateway.
    """
    notifications_in_range = context.notification_gateway.fetch_notifications(date_range)

    notifications_with_published_data = context.db_gateway.fetch_notifications_with_publish_data(notifications_in_range)

    notifications_to_publish = unpublished_notifications(notifications_with_published_data)

    published_notifications = context.publish_gateway.publish(notifications_to_publish)

    context.db_gateway.set_notifications_published(published_notifications)


# Delivery

notification_gateway = NotificationGateway('host', 'port')
db_gateway = DbGateway('host', 'port')
publish_gateway = PublishGateway()

context = (notification_gateway, db_gateway, publish_gateway)

while True:
    publish_new_notifications(context,
                            date_range)
    time.sleep(15)