import json import typing from django.apps import apps from django.conf import settings from django.core.exceptions import ObjectDoesNotExist, ValidationError from django.db import models from django.db.models import Q from django.urls import reverse from django.utils.functional import cached_property from django.utils.translation import ugettext_lazy as _ from django.utils.translation import ungettext_lazy from c3nav.editor.wrappers import ModelInstanceWrapper, ModelWrapper class ChangeSet(models.Model): created = models.DateTimeField(auto_now_add=True, verbose_name=_('created')) author = models.ForeignKey(settings.AUTH_USER_MODEL, null=True, on_delete=models.PROTECT, verbose_name=_('Author')) proposed = models.DateTimeField(null=True, verbose_name=_('proposed')) applied = models.DateTimeField(null=True, verbose_name=_('applied')) applied_by = models.ForeignKey(settings.AUTH_USER_MODEL, null=True, on_delete=models.PROTECT, related_name='applied_changesets', verbose_name=_('applied by')) class Meta: verbose_name = _('Change Set') verbose_name_plural = _('Change Sets') default_related_name = 'changesets' def __init__(self, *args, **kwargs): super().__init__(*args, **kwargs) self.default_author = None self.parsed = False self.updated_existing = {} self.deleted_existing = {} self.m2m_add_existing = {} self.m2m_remove_existing = {} def parse_changes(self): if self.parsed: return for change in self.changes.all(): self._parse_change(change) def _parse_change(self, change): if change.action == 'delchange': raise NotImplementedError model = change.model_class if change.action == 'create': raise NotImplementedError elif change.action == 'delete': if change.existing_object_pk is not None: self.deleted_existing.setdefault(model, set()).add(change.existing_object_pk) else: raise NotImplementedError return value = json.loads(change.field_value) if change.existing_object_pk is None: raise NotImplementedError if change.action == 'update': value = json.loads(change.field_value) self.updated_existing.setdefault(model, {}).setdefault(change.obj_pk, {}).update({ change.field_name: value }) elif change.action == 'm2m_add': self.m2m_add_existing.setdefault(model, {}).setdefault(change.obj_pk, set()).add(value) elif change.action == 'm2m_add': self.m2m_remove_existing.setdefault(model, {}).setdefault(change.obj_pk, set()).add(value) @classmethod def qs_base(cls, hide_applied=True): qs = cls.objects.prefetch_related('changes').select_related('author') if hide_applied: qs = qs.filter(applied__isnull=True) return qs @classmethod def qs_for_request(cls, request): qs = cls.qs_base() if request.user.is_authenticated(): qs = qs.filter(Q(author__isnull=True) | Q(author=request.user)) else: qs = qs.filter(author__isnull=True) return qs @classmethod def get_for_request(cls, request): qs = cls.qs_for_request(request) changeset_pk = request.session.get('changeset_pk', None) if changeset_pk is not None: changeset = qs.filter(pk=changeset_pk).first() if changeset is not None: changeset.default_author = request.user if changeset.author_id is None and request.user.is_authenticated(): changeset.author = request.user changeset.save() return changeset new_changeset = cls() if request.user.is_authenticated(): changeset = qs.filter(Q(author=request.user)).order_by('-created').first() if changeset is not None: request.session['changeset_pk'] = changeset.pk changeset.default_author = request.user return changeset new_changeset.author = request.user new_changeset.save() request.session['changeset_pk'] = new_changeset.pk new_changeset.default_author = request.user return new_changeset def get_absolute_url(self): return reverse('editor.changesets.detail', kwargs={'pk': self.pk}) @cached_property def undeleted_changes_count(self): return len([True for change in self.changes.all() if change.deletes_change_id is None]) @property def title(self): return _('Changeset #%d') % self.pk @property def count_display(self): return ungettext_lazy('%(num)d Change', '%(num)d Changes', 'num') % {'num': self.undeleted_changes_count} def wrap(self, obj, author=None): self.parse_changes() if author is None: author = self.default_author if author is not None and not author.is_authenticated(): author = None if isinstance(obj, str): return ModelWrapper(self, apps.get_model('mapdata', obj), author) if isinstance(obj, type) and issubclass(obj, models.Model): return ModelWrapper(self, obj, author) if isinstance(obj, models.Model): return ModelWrapper(self, type(obj), author).create_wrapped_model_class()(self, obj, author) raise ValueError def _new_change(self, author, **kwargs): self.parse_changes() change = Change(changeset=self) change.changeset_id = self.pk author = self.default_author if author is None else author if author is not None and author.is_authenticated(): change.author = author for name, value in kwargs.items(): setattr(change, name, value) change.save() self._parse_change(change) return change def add_create(self, obj, author=None): change = self._new_change(author=author, action='create', model_class=type(obj._obj)) obj.pk = 'c%d' % change.pk def _add_value(self, action, obj, name, value, author=None): return self._new_change(author=author, action=action, obj=obj, field_name=name, field_value=json.dumps(value, ensure_ascii=False)) def add_update(self, obj, name, value, author=None): return self._add_value('update', obj, name, value, author) def add_m2m_add(self, obj, name, value, author=None): return self._add_value('m2m_add', obj, name, value, author) def add_m2m_remove(self, obj, name, value, author=None): return self._add_value('m2m_remove', obj, name, value, author) def add_delete(self, obj, author=None): return self._new_change(author=author, action='delete', obj=obj) class Change(models.Model): ACTIONS = ( ('delchange', _('delete change')), ('create', _('create object')), ('delete', _('delete object')), ('update', _('update attribute')), ('m2m_add', _('add many to many relation')), ('m2m_remove', _('add many to many relation')), ) changeset = models.ForeignKey(ChangeSet, on_delete=models.CASCADE, verbose_name=_('Change Set')) author = models.ForeignKey(settings.AUTH_USER_MODEL, null=True, on_delete=models.PROTECT, verbose_name=_('Author')) created = models.DateTimeField(auto_now_add=True, verbose_name=_('created')) action = models.CharField(max_length=16, choices=ACTIONS, verbose_name=_('action')) deletes_change = models.OneToOneField('Change', null=True, on_delete=models.CASCADE, related_name='deleted_by', verbose_name=_('deletes change')) model_name = models.CharField(max_length=50, null=True, verbose_name=_('model name')) existing_object_pk = models.PositiveIntegerField(null=True, verbose_name=_('id of existing object')) created_object = models.ForeignKey('Change', null=True, on_delete=models.CASCADE, related_name='changed_by', verbose_name=_('changed object')) field_name = models.CharField(max_length=50, null=True, verbose_name=_('field name')) field_value = models.TextField(null=True, verbose_name=_('new field value')) class Meta: verbose_name = _('Change') verbose_name_plural = _('Changes') default_related_name = 'changes' ordering = ['created', 'pk'] def __init__(self, *args, **kwargs): super().__init__(*args, **kwargs) self._set_object = None @property def model_class(self) -> typing.Optional[typing.Type[models.Model]]: if self.model_name is None: return None return apps.get_model('mapdata', self.model_name) @model_class.setter def model_class(self, value: typing.Optional[typing.Type[models.Model]]): if value is None: self.model_name = None return if not issubclass(value, models.Model): raise ValueError('value is not a django model') if value._meta.abstract: raise ValueError('value is an abstract model') if value._meta.app_label != 'mapdata': raise ValueError('value is not a mapdata model') self.model_name = value.__name__ @property def obj_pk(self) -> typing.Union[int, str]: if self._set_object is not None: return self._set_object.pk if self.existing_object_pk is not None: return self.existing_object_pk if self.created_object is not None: return 'c'+str(self.created_object.changeset_id) raise TypeError('existing_model_pk or created_object have to be set.') @property def obj(self) -> ModelInstanceWrapper: if self._set_object is not None: return self._set_object if self.existing_object_pk is not None: if self.created_object is not None: raise TypeError('existing_object_pk and created_object can not both be set.') self._set_object = self.changeset.wrap(self.model_class.objects.get(pk=self.existing_object_pk)) # noinspection PyTypeChecker return self._set_object elif self.created_object is not None: if self.created_object.model_class != self.model_class: raise TypeError('created_object model and change model do not match.') if self.created_object.changeset_id != self.changeset_id: raise TypeError('created_object belongs to a different changeset.') raise NotImplementedError raise TypeError('existing_model_pk or created_object have to be set.') @obj.setter def obj(self, value: typing.Union[models.Model, ModelInstanceWrapper]): if not isinstance(value, ModelInstanceWrapper): value = self.changeset.wrap(value) if isinstance(value.pk, str): if value._changeset.id != self.changeset.pk: raise ValueError('value is a Change instance but belongs to a different changeset.') self.model_class = type(value._obj) self.created_object = Change.objects.get(pk=value.pk[1:]) self.created_object_id = int(value.pk[1:]) self.existing_object_pk = None self._set_object = value return model_class_before = self.model_class self.model_class = type(value._obj) if isinstance(value, ModelInstanceWrapper) else type(value) if value.pk is None: self.model_class = model_class_before raise ValueError('object is not saved yet and cannot be referenced') self.existing_object_pk = value.pk self.created_object = None self._set_object = value def clean(self): if self.action == 'delchange': if self.deletes_change is None: raise ValidationError('deletes_change has to be set if action is delchange.') if self.deletes_change.changeset_id != self.changeset_id: raise ValidationError('deletes_change refers to a change from a different changeset.') for field_name in ('model_name', 'existing_object_pk', 'created_object', 'field_name', 'field_value'): if getattr(self, field_name) is not None: raise ValidationError('%s must not be set if action is delchange.' % field_name) return if self.deletes_change is not None: raise ValidationError('deletes_change can only be set if action is delchange.') if self.model_name is None: raise ValidationError('model_name has to be set if action is not delchange.') try: # noinspection PyUnusedLocal tmp = self.model_class if self.action == 'create' else self.obj # noqa except TypeError as e: raise ValidationError(str(e)) except ObjectDoesNotExist: raise ValidationError('existing object does not exist.') if self.action in ('create', 'delete'): for field_name in ('field_name', 'field_value'): if getattr(self, field_name) is not None: raise ValidationError('%s must not be set if action is create or delete.' % field_name) def save(self, *args, **kwargs): self.clean() if self.pk is not None: raise TypeError('change objects can not be edited.') if self.changeset.proposed is not None or self.changeset.applied is not None: raise TypeError('can not add change object to uneditable changeset.') super().save(*args, **kwargs) def delete(self, *args, **kwargs): raise TypeError('change objects can not be deleted directly.') def __repr__(self): result = '