1 from pytask.profile.models import Notification

     2 

     3 def get_notification(nid, user):

     4     """ if notification exists, and belongs to the current user, return it.

     5     else return None.

     6     """

     7 

     8     user_notifications = user.notification_sent_to.filter(is_deleted=False).order_by('sent_date')

     9     current_notifications = user_notifications.filter(uniq_key=nid)

    10     if user_notifications:

    11         current_notification = current_notifications[0]

    12 

    13         try:

    14             newer_notification = current_notification.get_next_by_sent_date(sent_to=user, is_deleted=False)

    15             newest_notification = user_notifications.reverse()[0]

    16             if newest_notification == newer_notification:

    17                 newest_notification = None

    18         except Notification.DoesNotExist:

    19             newest_notification, newer_notification = None, None

    20 

    21         try:

    22             older_notification = current_notification.get_previous_by_sent_date(sent_to=user, is_deleted=False)

    23             oldest_notification = user_notifications[0]

    24             if oldest_notification == older_notification:

    25                 oldest_notification = None

    26         except:

    27             oldest_notification, older_notification = None, None

    28 

    29         return newest_notification, newer_notification, current_notification, older_notification, oldest_notification

    30 

    31     else:

    32         return None, None, None, None, None