80 lines
2.4 KiB
Python
80 lines
2.4 KiB
Python
from django.contrib.contenttypes.models import ContentType
|
|
from django.db import models
|
|
|
|
from adminsortable.fields import SortableForeignKey
|
|
|
|
|
|
class MultipleSortableForeignKeyException(Exception):
|
|
def __init__(self, value):
|
|
self.value = value
|
|
|
|
def __str__(self):
|
|
return repr(self.value)
|
|
|
|
|
|
class Sortable(models.Model):
|
|
"""
|
|
Unfortunately, Django doesn't support using more than one AutoField
|
|
in a model or this class could be simplified.
|
|
|
|
`is_sortable` determines whether or not the Model is sortable by
|
|
determining if the last value of `order` is greater than the default
|
|
of 1, which should be present if there is only one object.
|
|
|
|
`model_type_id` returns the ContentType.id for the Model that
|
|
inherits Sortable
|
|
|
|
`save` the override of save increments the last/highest value of
|
|
order by 1
|
|
"""
|
|
|
|
order = models.PositiveIntegerField(editable=False, default=1,
|
|
db_index=True)
|
|
is_sortable = False
|
|
|
|
# legacy support
|
|
sortable_by = None
|
|
|
|
class Meta:
|
|
abstract = True
|
|
ordering = ['order']
|
|
|
|
# @classmethod
|
|
# def determine_if_sortable(cls):
|
|
# try:
|
|
# max_order = cls.objects.aggregate(
|
|
# models.Max('order'))['order__max']
|
|
# except (TypeError, IndexError):
|
|
# max_order = 0
|
|
|
|
# if max_order > 1:
|
|
# cls.is_sortable = True
|
|
# else:
|
|
# cls.is_sortable = False
|
|
|
|
@classmethod
|
|
def model_type_id(cls):
|
|
return ContentType.objects.get_for_model(cls).id
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
super(Sortable, self).__init__(*args, **kwargs)
|
|
|
|
# Validate that model only contains at most one SortableForeignKey
|
|
sortable_foreign_keys = []
|
|
for field in self._meta.fields:
|
|
if isinstance(field, SortableForeignKey):
|
|
sortable_foreign_keys.append(field)
|
|
if len(sortable_foreign_keys) > 1:
|
|
raise MultipleSortableForeignKeyException(
|
|
u'%s may only have one SortableForeignKey' % self)
|
|
|
|
def save(self, *args, **kwargs):
|
|
if not self.id:
|
|
try:
|
|
self.order = self.__class__.objects.aggregate(
|
|
models.Max('order'))['order__max'] + 1
|
|
except (TypeError, IndexError):
|
|
pass
|
|
|
|
super(Sortable, self).save(*args, **kwargs)
|