fix: Organize revenue by year in admin page

accounting/admin.py

@@ -6,11 +6,39 @@
 from django.utils.translation import gettext_lazy as _
 
 
+class RevenueDescendingFilter(admin.SimpleListFilter):
+    title = _("Year")
+    parameter_name = "fair__year"
+
+    def lookups(self, request, model_admin):
+        # Retrieve all unique years from the related model and sort them in descending order
+        years = (
+            model_admin.model.objects.order_by("-fair__year")
+            .values_list("fair__year", flat=True)
+            .distinct()
+        )
+        return [(year, year) for year in years]
+
+    # Default to current year selected
+    def value(self):
+        # Default to the current year if no specific value is selected
+        if not self.used_parameters.get(self.parameter_name):
+            return str(datetime.now().year)
+        return super().value()
+
+    def queryset(self, request, queryset):
+        if self.value():
+            return queryset.filter(fair__year=self.value())
+        return queryset
+
+
 @admin.register(Revenue)
 class RevenueAdmin(ModelAdminImproved):
-    ordering = ["name"]
+    ordering = ["-fair__year"]
     list_display = ["name", "description", "fair"]
-    list_filter = ["fair__year"]
+    list_filter = [RevenueDescendingFilter]
+
+
 class CategoryDescendingFilter(admin.SimpleListFilter):
     title = _("Year")
     parameter_name = "fair__year"