changes toi the downgrading

Website/main.py

@@ -2313,6 +2313,9 @@ def _get_downgrade_options(instance: dict | None) -> list[dict]:
 
 
 def _booking_restriction(instance: dict | None, package_list: list[str], booking_action: str) -> str | None:
+    if booking_action == "downgrade" and (not instance or instance.get("is_trial")):
+        return "Eine Herabstufung ist nur für eine bestehende, regulär gebuchte Instanz möglich."
+
     if not instance or instance.get("is_trial"):
         return None
 
@@ -3059,6 +3062,9 @@ def booking_payment():
     form_data["existing_subdomain"] = existing_subdomain
     if not form_data["tenant_slug"] and existing_subdomain:
         form_data["tenant_slug"] = existing_subdomain
+    if booking_action == "downgrade":
+        form_data["tenant_slug"] = _sanitize_text((owned_instance or {}).get("subdomain") or "", 63)
+        form_data["confirm_subdomain_change"] = True
 
     if request.method == "GET" and not form_data["contact_person"]:
         form_data["contact_person"] = session.get("display_name") or session.get("username") or ""
@@ -3211,7 +3217,9 @@ def booking_payment():
             subdomain = effective_subdomain[:63]
 
             reuse_instance = None
-            if active_trial and active_trial.get("subdomain") == requested_subdomain:
+            if booking_action == "downgrade":
+                reuse_instance = owned_instance
+            elif active_trial and active_trial.get("subdomain") == requested_subdomain:
                 reuse_instance = active_trial
             elif owned_instance and owned_instance.get("subdomain") == requested_subdomain:
                 reuse_instance = owned_instance

Website/templates/preise.html

@@ -80,6 +80,12 @@
 
     .notice { padding: 1.3rem 1.35rem; border-radius: 20px; background: #ffffff; border: 1px solid #dfe7ea; color: #304f5a; box-shadow: 0 12px 24px rgba(23, 44, 57, 0.04); }
     .notice strong { color: #15444c; }
+    .booking-guide {
+        margin-bottom: 1.8rem;
+        background: #f7fbfb;
+        border-color: #c7dde3;
+    }
+    .booking-guide p { margin: 0.45rem 0 0; }
 
     /* Modals */
     .custom-modal {
@@ -158,6 +164,10 @@
     <strong>Ihre gebuchte Version bleibt bestehen.</strong>
     <span> Bereits enthalten: {{ paid_instance.package or 'aktueller Paketumfang' }}. Sie können nur zusätzliche Module buchen.</span>
 </div>
+<div class="notice booking-guide">
+    <strong>Was Sie jetzt buchen können</strong>
+    <p>Bereits enthaltene Module werden hier nicht erneut angeboten. Die verbleibenden Module können Sie einzeln in den Warenkorb legen. Für mehrere Schulen oder besondere Anforderungen können Sie ein individuelles Angebot anfragen; passende Barcodes führen wir direkt zu unserem Anbieter weiter.</p>
+</div>
 {% endif %}
 
 <section class="packages-grid" aria-label="Buchungspakete">
@@ -192,6 +202,7 @@
     </article>
     {% endif %}
     <!-- INVENTARSYSTEM -->
+    {% if 'inventory' not in current_module_keys %}
     <article class="package-card">
         <div class="package-card__header">
             <div>
@@ -219,8 +230,10 @@
             {% endif %}
         </div>
     </article>
+    {% endif %}
 
     <!-- BIBLIOTHEKSSYSTEM -->
+    {% if 'library' not in current_module_keys %}
     <article class="package-card">
         <div class="package-card__header">
             <div>
@@ -247,8 +260,10 @@
             {% endif %}
         </div>
     </article>
+    {% endif %}
 
     <!-- TERMINPLANER -->
+    {% if 'terminplan' not in current_module_keys %}
     <article class="package-card">
         <div class="package-card__header">
             <div>
@@ -276,6 +291,7 @@
             {% endif %}
         </div>
     </article>
+    {% endif %}
 
     <!-- SCHULTRÄGER -->
     <article class="package-card">