#343 Drop redundant logic from siblings fetching. High level arch for…

… breadcrumbs

pages/logic/__init__.py

@@ -0,0 +1,3 @@
+from .page import *
+
+__all__ = ['page']

pages/logic/page.py

@@ -0,0 +1,43 @@
+import typing
+
+from pages import models
+
+
+class Page:
+    def __init__(self, model: models.Page):
+        # "record" is much more good field name, i suppose.
+        # But "model" is Django standard.
+        self.model = model
+
+    def breadcrumbs(self) -> 'Breadcrumbs':
+        pass
+
+    @property
+    def siblings(self) -> models.PageQuerySet:
+        return self.model.parent.children.exclude(id=self.model.id)
+
+
+# @todo #343:60m  Implement Breadcrumbs class.
+#  Use it instead of monolithic logic at the `breadcrumbs_with_siblings`.
+#  Create Breadcrumb class or named tuple to specify crumb data structure.
+class Breadcrumbs:
+    def __init__(self, page_model: models.Page):
+        self.model = page_model
+
+    def query(self, include_self: bool) -> models.PageQuerySet:
+        return (
+            self.model
+            .get_ancestors(include_self)
+            .select_related(self.model.related_model_name)
+            .active()
+        )
+
+    def list(self, include_self=False) -> typing.List[typing.Tuple[str, str]]:
+        """Breadcrumbs list consists of current page ancestors."""
+        return [
+            (crumb.display_menu_title, crumb.url)
+            for crumb in self.query(include_self).iterator()
+        ]
+
+    def list_with_self(self) -> list:
+        return self.list(include_self=True)

pages/templatetags/pages_extras.py

@@ -2,6 +2,7 @@
 from django.conf import settings
 from django.core.urlresolvers import reverse
 
+from pages import logic
 from pages.models import CustomPage, FlatPage, Page
 
 register = template.Library()
@@ -28,21 +29,6 @@ def breadcrumbs(page: Page, separator='', base_url=''):
 def breadcrumbs_with_siblings(
     page: Page, separator='', base_url='', include_self=False
 ):
-    def get_siblings(page):
-        def is_node(page):
-           return hasattr(page.model, 'children')
-
-        if not is_node(page):
-            return []
-
-        siblings = page.get_siblings().select_related(page.related_model_name)
-
-        return [
-            sibling
-            for sibling in siblings
-            if is_node(sibling)
-        ]
-
     def get_ancestors_crumbs() -> list:
         ancestors_query = (
             page
@@ -56,16 +42,14 @@ def get_ancestors_crumbs() -> list:
 
         catalog, *ancestors = ancestors_query
 
-        siblings = [
-            get_siblings(ancestor)
-            for ancestor in ancestors
-        ]
-
         return [
             (catalog.display_menu_title, catalog.url, []),
             *[
-                (crumb.display_menu_title, crumb.url, crumb_links)
-                for crumb, crumb_links in zip(ancestors, siblings)
+                (
+                    crumb.display_menu_title,
+                    crumb.url,
+                    list(logic.Page(page).siblings)
+                ) for crumb in ancestors
             ],
         ]
 
@@ -74,7 +58,7 @@ def get_ancestors_crumbs() -> list:
     crumbs_list = [
         (index.display_menu_title, index.url, []) if index else ('Main', '/', []),
         *get_ancestors_crumbs(),
-        (page.display_menu_title, '', get_siblings(page))
+        (page.display_menu_title, '', logic.Page(page).siblings)
     ]
 
     return {

tests/pages/logic/test_page.py

@@ -0,0 +1,21 @@
+from django.test import TestCase
+
+from pages import models
+
+
+class PageTests(TestCase):
+    fixtures = ['catalog.json']
+
+    @property
+    def page(self):
+        return (
+            models.Page.objects
+            .active()
+            .filter(type=models.Page.MODEL_TYPE)
+            .exclude(parent=None)
+            .exclude(parent=models.CustomPage.objects.get(slug='catalog'))
+            .first()
+        )
+
+    def test_breadcrumbs(self):
+        ...