# This is the denormalisation engine

# his goal is to leverage on django's signal to update

# denormalized fields

# this should be used with beanstalk or starling

# python client (there is 2) http://github.com/earl/beanstalkc/tree/master

import logging

from django.db.models import signals

from cm.models import TextVersion, Text

# Text denormalisation

def update_text_from_last_version(sender, **kwargs):

    """

    Update text's last version

    """

    text_version = kwargs['instance']

    try:

        text = text_version.text

        text.update_denorm_fields()

    except Text.DoesNotExist:

        pass

        #logging.warning('No text found for text_version: %i' %text_version.id)

# GIB when deleting last revision, do not delete related text

def delete_last_version (sender, instance, signal, *args, **kwargs):

  if instance.id == instance.text.last_text_version_id:

    previous = instance.get_previous_version()

    if previous:

      instance.text.last_text_version_id = previous.id

      instance.text.save()

def connect_all():

    # text updated by text_version

    signals.pre_delete.connect(delete_last_version, sender=TextVersion)

    signals.post_save.connect(update_text_from_last_version, sender=TextVersion)

    signals.post_delete.connect(update_text_from_last_version, sender=TextVersion)

connect_all()