feat: sort groups price services by price first, then alphabetically

src/Service/AccommodationBookingService.php

@@ -156,6 +156,12 @@ class AccommodationBookingService
             }
         }
 
+        $boardServices = $this->sortServicesByPriceThenLabel($boardServices);
+        $ungrouped = $this->sortServicesByPriceThenLabel($ungrouped);
+        foreach ($grouped as $groupName => $groupServices) {
+            $grouped[$groupName] = $this->sortServicesByPriceThenLabel($groupServices);
+        }
+
         return [
             'boardServices' => $boardServices,
             'additionalServices' => $additionalServices,
@@ -164,6 +170,27 @@ class AccommodationBookingService
         ];
     }
 
+    /**
+     * Free services (price 0) first, then alphabetically; each group sorted alphabetically.
+     *
+     * @template T of BoardService|AdditionalService
+     *
+     * @param T[] $services
+     *
+     * @return T[]
+     */
+    private function sortServicesByPriceThenLabel(array $services): array
+    {
+        usort($services, static function (BoardService|AdditionalService $a, BoardService|AdditionalService $b): int {
+            $aFree = 0 === $a->getPrice() ? 0 : 1;
+            $bFree = 0 === $b->getPrice() ? 0 : 1;
+
+            return $aFree <=> $bFree ?: strnatcasecmp($a->getLabel(), $b->getLabel());
+        });
+
+        return $services;
+    }
+
     /**
      * Determines whether the booking must be treated as non-binding and why.
      *