From 8d4112218802d48473fc8c7a06c92271ac8772d4 Mon Sep 17 00:00:00 2001
From: duker <duker33@gmail.com>
Date: Fri, 31 Aug 2018 14:43:03 +0300
Subject: [PATCH] #550  Implement CatalogContext

---
 shopelectro/context.py       | 155 +++++++++++++++++++++++++++++++++++
 shopelectro/views/catalog.py |  21 +----
 2 files changed, 159 insertions(+), 17 deletions(-)
 create mode 100644 shopelectro/context.py

diff --git a/shopelectro/context.py b/shopelectro/context.py
new file mode 100644
index 00000000..7daf610d
--- /dev/null
+++ b/shopelectro/context.py
@@ -0,0 +1,155 @@
+"""
+Contains view context classes.
+Context is part of the View abstract layer in MTV paradigm.
+It stands between urls and view functions.
+
+Every context class is used via objects composition.
+For example:
+TODO - add example of objects composition
+"""
+
+import typing
+from functools import lru_cache, partial
+
+from django import http
+from django.db.models import QuerySet
+from django.conf import settings
+from django.core.paginator import Paginator, InvalidPage
+from django.shortcuts import render, get_object_or_404
+from django.views.decorators.http import require_POST
+from django_user_agents.utils import get_user_agent
+
+from catalog.views import catalog
+from images.models import Image
+from pages import views as pages_views
+
+from shopelectro import models
+from shopelectro.views.helpers import set_csrf_cookie
+
+from pages.models import ModelPage, Page
+
+
+@lru_cache(maxsize=64)
+def merge_products_context(products):
+    images = Image.objects.get_main_images_by_pages(
+        models.ProductPage.objects.filter(shopelectro_product__in=products)
+    )
+
+    # TODO - create product.get_brand instead
+    brands = (
+        models.Tag.objects
+        .filter_by_products(products)
+        .get_brands(products)
+    )
+
+    return [
+        (product, images.get(product.page), brands.get(product))
+        for product in products
+    ]
+
+
+class ObjectsComposition:
+
+    super = object()
+
+    def __or__(self, other):
+        self.super = other
+
+
+class AbstractContext(ObjectsComposition):
+
+    # TODO - raise not implemented here
+    # @property
+    # def request(self):
+    #     raise NotImplemented()
+
+    # @property
+    # def page(self) -> Page:
+    #     """Page from DB, that should be selected"""
+    #     raise NotImplemented()
+
+    def get_context_data(self, **kwargs) -> dict:
+        raise NotImplemented()
+
+
+class ProductsListContext(AbstractContext):
+    @property
+    def products(self) -> QuerySet:
+        raise NotImplemented()
+
+
+# TODO - fork PageContext
+class CategoryContext(ProductsListContext):
+
+    # TODO - annotate it
+    def __init__(self, slug, request):
+        self.slug = slug
+        self.request = request
+
+    @property
+    @lru_cache(maxsize=1)
+    def page(self):
+        return ModelPage.objects.get(slug=self.slug)
+
+    @property
+    @lru_cache(maxsize=1)
+    def products(self) -> QuerySet:
+        return models.Product.actives.get_category_descendants(
+            self.page.model
+        )
+
+    def get_context_data(self, **kwargs):
+        """Add sorting options and view_types in context."""
+        # TODO take from dataclass or smth
+        view_type = self.request.session.get('view_type', 'tile')
+
+        group_tags_pairs = (
+            models.Tag.objects
+            .filter_by_products(self.products)
+            .get_group_tags_pairs()
+        )
+
+        return {
+            'products_data': merge_products_context(self.products),
+            'group_tags_pairs': group_tags_pairs,
+            # TODO add comment about view_type
+            'view_type': view_type,
+        }
+
+
+# class TaggedCategoryContext:
+#     def products(tags):
+#         return self.super.products().and_aother_fetch(catalog)
+#
+#     def get_context_data():
+#         return {
+#             **self.super.get_context_data(),
+#             ...  # and something simple only about tags
+#         }
+#
+#
+# class PaginatedCatalogContext:
+#     ...
+#
+#
+# class DBTemplateContext:
+#     ...
+#
+#
+# class CatalogView:
+#     def get_context_data(category_id, page_num):
+#         category = some_fetch(category_id)
+#         context = CatalogContext(category) | PaginatedCatalogContext(page_num)
+#         return context.get_context_data()
+#
+#
+# class TaggedCatalogView:
+#     def get_context_data(category_id, page_num, tags):
+#         category = some_fetch(category_id)
+#         context = (
+#             CatalogContext(category)
+#             | PaginatedCatalogContext(page_num)
+#             | TaggedCatalogContext(tags)
+#             | DBTemplateContext(tags)
+#         )
+#         return context.get_context_data()
diff --git a/shopelectro/views/catalog.py b/shopelectro/views/catalog.py
index a32e7679..a73be597 100644
--- a/shopelectro/views/catalog.py
+++ b/shopelectro/views/catalog.py
@@ -13,7 +13,7 @@
 from images.models import Image
 from pages import views as pages_views
 
-from shopelectro import models
+from shopelectro import context, models
 from shopelectro.views.helpers import set_csrf_cookie
 
 PRODUCTS_ON_PAGE_PC = 48
@@ -189,23 +189,10 @@ def get_products(self) -> QuerySet:
 
     def get_context_data(self, **kwargs):
         """Add sorting options and view_types in context."""
-        # TODO take from dataclass or smth
-        view_type = self.request.session.get('view_type', 'tile')
-        context = super().get_context_data(**kwargs)
-
-        products = self.get_products()
-        group_tags_pairs = (
-            models.Tag.objects
-            .filter_by_products(products)
-            .get_group_tags_pairs()
-        )
-
+        context_ = context.CategoryContext(self.object.slug, self.request)
         return {
-            **context,
-            'products_data': merge_products_context(products),
-            'group_tags_pairs': group_tags_pairs,
-            # TODO add comment about view_type
-            'view_type': view_type,
+            **super().get_context_data(**kwargs),
+            **context_.get_context_data(),
         }