Code refactoring to simplify template data contexts (#55)

* Fix a search filter when no catalogs are returned
* Code refactoring to simplify templates
* Remove duplicated code
* Remove dead code
* More improvements, clean up and add featured items in homepage
* Fix a type and better page navigation

ram/roster/admin.py

@@ -44,7 +44,9 @@ class RollingClass(admin.ModelAdmin):
     @admin.display(description="Country")
     def country_flag(self, obj):
         return format_html(
-            '<img src="{}" /> {}', obj.country.flag, obj.country.name
+            '<img src="{}" title="{}" />',
+            obj.company.country.flag,
+            obj.company.country.name,
         )
 
 
@@ -128,9 +130,12 @@ class RollingStockAdmin(SortableAdminBase, admin.ModelAdmin):
         "item_number",
         "company",
         "country_flag",
+        "featured",
         "published",
     )
     list_filter = (
+        "featured",
+        "published",
         "rolling_class__type__category",
         "rolling_class__type",
         "rolling_class__company__name",
@@ -152,7 +157,7 @@ class RollingStockAdmin(SortableAdminBase, admin.ModelAdmin):
     @admin.display(description="Country")
     def country_flag(self, obj):
         return format_html(
-            '<img src="{}" /> {}', obj.country.flag, obj.country.name
+            '<img src="{}" title="{}" />', obj.country.flag, obj.country.name
         )
 
     fieldsets = (
@@ -162,6 +167,7 @@ class RollingStockAdmin(SortableAdminBase, admin.ModelAdmin):
                 "fields": (
                     "preview",
                     "published",
+                    "featured",
                     "rolling_class",
                     "road_number",
                     "scale",
@@ -224,8 +230,8 @@ class RollingStockAdmin(SortableAdminBase, admin.ModelAdmin):
         if obj.invoice.exists():
             html = format_html_join(
                 "<br>",
-                "<a href=\"{}\" target=\"_blank\">{}</a>",
-                ((i.file.url, i) for i in obj.invoice.all())
+                '<a href="{}" target="_blank">{}</a>',
+                ((i.file.url, i) for i in obj.invoice.all()),
             )
         else:
             html = "-"
@@ -296,4 +302,38 @@ class RollingStockAdmin(SortableAdminBase, admin.ModelAdmin):
         return generate_csv(header, data, "rolling_stock.csv")
 
     download_csv.short_description = "Download selected items as CSV"
-    actions = [publish, unpublish, download_csv]
+
+    def set_featured(modeladmin, request, queryset):
+        count = queryset.count()
+        if count > settings.FEATURED_ITEMS_MAX:
+            modeladmin.message_user(
+                request,
+                "You can only mark up to {} items as featured.".format(
+                    settings.FEATURED_ITEMS_MAX
+                ),
+                level="error",
+            )
+            return
+        featured = RollingStock.objects.filter(featured=True).count()
+        if featured + count > settings.FEATURED_ITEMS_MAX:
+            modeladmin.message_user(
+                request,
+                "There are already {} featured items. You can only mark {} more items as featured.".format(  # noqa: E501
+                    featured,
+                    settings.FEATURED_ITEMS_MAX - featured,
+                ),
+                level="error",
+            )
+            return
+        queryset.update(featured=True)
+
+    set_featured.short_description = "Mark selected rolling stock as featured"
+
+    def unset_featured(modeladmin, request, queryset):
+        queryset.update(featured=False)
+
+    unset_featured.short_description = (
+        "Unmark selected rolling stock as featured"
+    )
+
+    actions = [publish, unpublish, set_featured, unset_featured, download_csv]

ram/roster/migrations/0039_rollingstock_featured.py

@@ -0,0 +1,21 @@
+# Generated by Django 6.0 on 2025-12-24 13:39
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("roster", "0038_alter_rollingstock_rolling_class"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="rollingstock",
+            name="featured",
+            field=models.BooleanField(
+                default=False,
+                help_text="Featured rolling stock will appear on the homepage",
+            ),
+        ),
+    ]

ram/roster/models.py

@@ -5,6 +5,7 @@ from django.db import models
 from django.urls import reverse
 from django.conf import settings
 from django.dispatch import receiver
+from django.core.exceptions import ValidationError
 
 from tinymce import models as tinymce
 
@@ -82,9 +83,7 @@ class RollingStock(BaseModel):
         help_text="Catalog item number or code",
     )
     item_number_slug = models.CharField(
-        max_length=32,
-        blank=True,
-        editable=False
+        max_length=32, blank=True, editable=False
     )
     set = models.BooleanField(
         default=False,
@@ -113,6 +112,10 @@ class RollingStock(BaseModel):
         null=True,
         blank=True,
     )
+    featured = models.BooleanField(
+        default=False,
+        help_text="Featured rolling stock will appear on the homepage",
+    )
     tags = models.ManyToManyField(
         Tag, related_name="rolling_stock", blank=True
     )
@@ -165,10 +168,18 @@ class RollingStock(BaseModel):
             os.path.join(
                 settings.MEDIA_ROOT, "images", "rollingstock", str(self.uuid)
             ),
-            ignore_errors=True
+            ignore_errors=True,
         )
         super(RollingStock, self).delete(*args, **kwargs)
 
+    def clean(self, *args, **kwargs):
+        if self.featured:
+            MAX = settings.FEATURED_ITEMS_MAX
+            if RollingStock.objects.filter(featured=True).count() > MAX - 1:
+                raise ValidationError(
+                    "There are already {} featured items".format(MAX)
+                )
+
 
 @receiver(models.signals.pre_save, sender=RollingStock)
 def pre_save_internal_fields(sender, instance, *args, **kwargs):
@@ -185,10 +196,7 @@ def pre_save_internal_fields(sender, instance, *args, **kwargs):
 
 def rolling_stock_image_upload(instance, filename):
     return os.path.join(
-        "images",
-        "rollingstock",
-        str(instance.rolling_stock.uuid),
-        filename
+        "images", "rollingstock", str(instance.rolling_stock.uuid), filename
     )