From e56d5aa137aa38c1f47bde3c71fc4801902ae708 Mon Sep 17 00:00:00 2001
From: Iacopo Spalletti <i.spalletti@nephila.it>
Date: Wed, 3 Aug 2016 09:00:46 +0200
Subject: [PATCH] Add very stupid check to avoid circular relationships for
 BlogCategory

---
 djangocms_blog/admin.py                       |  6 +++++-
 djangocms_blog/forms.py                       | 14 +++++++++++++
 .../migrations/0025_auto_20160803_0858.py     | 21 +++++++++++++++++++
 djangocms_blog/models.py                      | 12 ++++++++++-
 4 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 djangocms_blog/migrations/0025_auto_20160803_0858.py

diff --git a/djangocms_blog/admin.py b/djangocms_blog/admin.py
index 8d479e0..5770c6a 100755
--- a/djangocms_blog/admin.py
+++ b/djangocms_blog/admin.py
@@ -19,7 +19,7 @@ from django.utils.translation import get_language_from_request, ugettext_lazy as
 from parler.admin import TranslatableAdmin
 
 from .cms_appconfig import BlogConfig
-from .forms import PostAdminForm
+from .forms import CategoryAdminForm, PostAdminForm
 from .models import BlogCategory, Post
 from .settings import get_setting
 
@@ -31,6 +31,10 @@ except ImportError:
 
 
 class BlogCategoryAdmin(EnhancedModelAdminMixin, ModelAppHookConfig, TranslatableAdmin):
+    form = CategoryAdminForm
+    list_display = [
+        'name', 'parent', 'all_languages_column',
+    ]
 
     def get_prepopulated_fields(self, request, obj=None):
         app_config_default = self._app_config_select(request, obj)
diff --git a/djangocms_blog/forms.py b/djangocms_blog/forms.py
index c1be621..5a67515 100644
--- a/djangocms_blog/forms.py
+++ b/djangocms_blog/forms.py
@@ -9,6 +9,20 @@ from taggit_autosuggest.widgets import TagAutoSuggest
 from .models import BlogCategory, BlogConfig, Post
 
 
+class CategoryAdminForm(TranslatableModelForm):
+
+    def __init__(self, *args, **kwargs):
+        super(CategoryAdminForm, self).__init__(*args, **kwargs)
+        if self.instance.pk:
+            self.fields['parent'].queryset = self.fields['parent'].queryset.exclude(
+                pk__in=[self.instance.pk] + [child.pk for child in self.instance.descendants()]
+            )
+
+    class Meta:
+        model = BlogCategory
+        fields = '__all__'
+
+
 class LatestEntriesForm(forms.ModelForm):
     def __init__(self, *args, **kwargs):
         super(LatestEntriesForm, self).__init__(*args, **kwargs)
diff --git a/djangocms_blog/migrations/0025_auto_20160803_0858.py b/djangocms_blog/migrations/0025_auto_20160803_0858.py
new file mode 100644
index 0000000..f613c9b
--- /dev/null
+++ b/djangocms_blog/migrations/0025_auto_20160803_0858.py
@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.9 on 2016-08-03 06:58
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('djangocms_blog', '0024_auto_20160706_1524'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='blogcategory',
+            name='parent',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='children', to='djangocms_blog.BlogCategory', verbose_name='parent'),
+        ),
+    ]
diff --git a/djangocms_blog/models.py b/djangocms_blog/models.py
index 1bd1df5..f601d46 100644
--- a/djangocms_blog/models.py
+++ b/djangocms_blog/models.py
@@ -60,7 +60,9 @@ class BlogCategory(TranslatableModel):
     """
     Blog category
     """
-    parent = models.ForeignKey('self', verbose_name=_('parent'), null=True, blank=True)
+    parent = models.ForeignKey(
+        'self', verbose_name=_('parent'), null=True, blank=True, related_name='children'
+    )
     date_created = models.DateTimeField(_('created at'), auto_now_add=True)
     date_modified = models.DateTimeField(_('modified at'), auto_now=True)
     app_config = AppHookConfigField(
@@ -79,6 +81,14 @@ class BlogCategory(TranslatableModel):
         verbose_name = _('blog category')
         verbose_name_plural = _('blog categories')
 
+    def descendants(self):
+        children = []
+        if self.children.exists():
+            children.extend(self.children.all())
+            for child in self.children.all():
+                children.extend(child.descendants())
+        return children
+
     @cached_property
     def linked_posts(self):
         return self.blog_posts.namespace(self.app_config.namespace)