Refactor webshop product labels (#2005)

* Implement business logic for webshop labels in model property
* Use templatetag for mapping 'label_type' to a css class

Author: 0xUnicorn

src/shop/models.py

@@ -580,7 +580,7 @@ def available_for_days(self):
 
     @property
     def left_in_stock(self):
-        if self.stock_amount:
+        if self.stock_amount is not None:
             # All orders that are not open and not cancelled count towards what has
             # been "reserved" from stock.
             #
@@ -604,6 +604,42 @@ def is_stock_available(self):
         # If there is no stock defined the product is generally available.
         return True
 
+    @property
+    def labels(self) -> list:
+        """Return list of label objects for this product."""
+        labels = []
+
+        if self.sub_products.all().exists():
+            labels.append({
+                "type": "bundle",
+                "text": "Bundle",
+            })
+
+        if self.stock_amount is not None:
+            if self.left_in_stock < 1 or not self.is_time_available:
+                labels.insert(0, {
+                    "type": "sold_out",
+                    "text": "Sold out!",
+                })
+
+                # Sold out is an exclusive state - no further labels apply
+                return labels
+
+            elif self.left_in_stock <= 10:
+                labels.append({
+                    "type": "low_stock",
+                    "text": f"Only {self.left_in_stock} left!",
+                })
+
+        if self.available_for_days < 20:
+            labels.append({
+                "type": "ending_soon",
+                "text": f"Sales end in {self.available_for_days} days!",
+            })
+
+        return labels
+
+
 
 class SubProductRelation(
     ExportModelOperationsMixin("sub_product_relation"),

src/shop/templates/labels/default.html

@@ -0,0 +1,3 @@
+{% load label_mapping %}
+
+<span class="badge {{ label.type|css_class }}">{{ label.text }}</span>

src/shop/templates/shop_index.html

@@ -58,43 +58,11 @@
                   {{ product.name }}
                 </a>
 
-
-                {% if product.stock_amount %}
-                  {% if product.left_in_stock <= 0 or not product.is_time_available %}
-                    <div class="label label-danger" style="margin-left: 1em;"><!-- We can replace the style when we upgrade to Bootstrap 5. -->
-                      Sold out!
-                    </div>
-                  {% else %}
-
-                    {% if product.left_in_stock <= 10 %}
-                      <div class="label label-info" style="margin-left: 1em;">
-                        Only {{ product.left_in_stock }} left!
-                      </div>
-                    {% endif %}
-
-                  {% endif %}
-
-                  {% if product.left_in_stock > 0 %}
-                    <div class="label label-info" style="margin-left: 1em;">
-                      Sales end in {{ product.available_for_days }} days!
-                    </dev>
-                  {% endif %}
-
-                {% else %}
-
-                  {% if product.available_for_days < 20 %}
-                    <div class="label label-info" style="margin-left: 1em;">
-                      Sales end in {{ product.available_for_days }} days!
-                    </dev>
-                  {% endif %}
-
-                {% endif %}
-
-                {% if product.has_subproducts %}
-                  <div class="label label-info" style="margin-left: 1em;"><!-- We can replace the style when we upgrade to Bootstrap 5. -->
-                    Bundle
-                  </div>
-                {% endif %}
+                <div class="ms-3">
+                  {% for label in product.labels %}
+                    {% include 'labels/default.html' with label=label %}
+                  {% endfor %}
+                </div>
 
               </td>
               <td>

src/shop/templatetags/__init__.py

@@ -0,0 +1,15 @@
+from django import template
+
+register = template.Library()
+
+@register.filter(name="css_class")
+def css_class(value: str) -> str:
+    """Templatetag for mapping a 'label_type' to a css class."""
+    map = {
+        "sold_out": "text-bg-danger",
+        "low_stock": "text-bg-warning",
+        "ending_soon": "text-bg-secondary",
+        "bundle": "text-bg-info",
+    }
+
+    return map.get(value, "text-bg-primary")

src/shop/templatetags/label_mapping.py

@@ -98,6 +98,106 @@ def test_product_is_available_from_now_on(self):
         self.assertTrue(product.is_available())
 
 
+class ProductLabelsTest(TestCase):
+    """Test logic about labels for products."""
+
+    def test_labels_for_product_not_available_by_stock(self):
+        """Test product.labels returns a 'sold_out' label object."""
+        product = ProductFactory(stock_amount=1)
+        OrderProductRelationFactory(product=product, order__open=None)
+
+        result = product.labels[0]
+
+        assert result.get("type") == "sold_out"
+        assert result.get("text") == "Sold out!"
+
+    def test_labels_for_product_avoid_other_labels_when_sold_out(self):
+        """Test product.labels not returning other labels when being sold out."""
+        available_in = DateTimeTZRange(
+            lower=timezone.now(),
+            upper=timezone.now() + timezone.timedelta(6),
+        )
+
+        # With available_in
+        product = ProductFactory(stock_amount=0, available_in=available_in)
+
+        result = product.labels[0]
+
+        assert len(product.labels) == 1
+        assert result.get("type") == "sold_out"
+        assert result.get("text") == "Sold out!"
+
+        # Without available_in
+        product = ProductFactory(stock_amount=0)
+
+        result = product.labels[0]
+
+        assert len(product.labels) == 1
+        assert result.get("type") == "sold_out"
+        assert result.get("text") == "Sold out!"
+
+    def test_labels_for_product_with_stock_below_or_equal_to_10(self):
+        """Test the product.labels returns a 'low_stock' label object."""
+        product = ProductFactory(stock_amount=11)
+
+        # No label with stock_amount=11
+        assert len(product.labels) == 0
+
+        OrderProductRelationFactory(product=product, order__open=None)
+        result = product.labels[0]
+
+        assert result.get("type") == "low_stock"
+        assert result.get("text") == "Only 10 left!"
+
+    def test_labels_for_product_ending_within_20_days(self):
+        """Test the product returns a 'ending_soon' label object."""
+        available_in = DateTimeTZRange(
+            lower=timezone.now(),
+            upper=timezone.now() + timezone.timedelta(6),
+        )
+
+        # With stock
+        product = ProductFactory(stock_amount=11, available_in=available_in)
+
+        result = product.labels[0]
+
+        assert result.get("type") == "ending_soon"
+        assert result.get("text") == "Sales end in 5 days!"
+
+        # Without stock
+        product = ProductFactory(available_in=available_in)
+
+        result = product.labels[0]
+
+        assert result.get("type") == "ending_soon"
+        assert result.get("text") == "Sales end in 5 days!"
+
+    def test_labels_for_product_is_empty_when_no_label_applies(self):
+        """
+        Test the product.labels returns an empty list when no label applies.
+        """
+        product = ProductFactory()
+
+        assert len(product.labels) == 0
+
+    def test_labels_for_product_when_being_a_bundle(self):
+        """Test the product.labels when product has subproduct (bundle)."""
+        bundle_product = ProductFactory()
+        sub_product = ProductFactory(
+            ticket_type=TicketTypeFactory(single_ticket_per_product=False),
+        )
+        bundle_product.sub_products.add(
+            sub_product,
+            through_defaults={"number_of_tickets": 5},
+        )
+
+        result = bundle_product.labels[0]
+
+        assert len(bundle_product.labels) == 1
+        assert result.get("type") == "bundle"
+        assert result.get("text") == "Bundle"
+
+
 class TestOrderProductRelationForm(TestCase):
     def test_clean_quantity_succeeds_when_stock_not_exceeded(self):
         product = ProductFactory(stock_amount=2)