Fix the concatenation issue with message

apps/notification/backend/business/notification_manager.py

@@ -86,26 +86,44 @@ class NotificationManager:
         properties: dict,
         region: Optional[UserRegion] = None,
     ) -> str:
-        # leverage the information in properties to enrich the message.
-        message_subject = None
-        message = None
-        if subject.lower() == "payment":
-            pass
-
-        # Default region to be international if not set
+        # Default region to international if not set
         if region is None:
             region = UserRegion.OTHER
 
-        message_subject = SystemNotifications[region][subject.lower()][event.lower()][
-            "message_subject"
-        ]
-        message = SystemNotifications[region][subject.lower()][event.lower()]["message"]
+        subject_lower = subject.lower()
+        event_lower = event.lower()
 
-        if event.lower() == "authentication":
-            message = message.format(properties["auth_code"])
-        if not message:
-            raise RuntimeError("unsupported event:{}".format(event))
-        return message, message_subject
+        try:
+            # Get message template and subject from SystemNotifications
+            notification_config = SystemNotifications[region][subject_lower][event_lower]
+            message = notification_config["message"]
+            message_subject = notification_config["message_subject"]
+
+            # Handle authentication specific formatting
+            if event_lower == "authentication" and "auth_code" in properties:
+                message = message.format(properties["auth_code"])
+
+            # Append content_text if it exists in properties
+            if properties.get("content_text"):
+                if isinstance(properties["content_text"], dict):
+                    # If content_text is a dictionary, use format with kwargs
+                    message = message.format(**properties["content_text"])
+                elif isinstance(properties["content_text"], str):
+                    # If content_text is a string, append it with proper spacing
+                    content = properties["content_text"].strip()
+                    if message and content:
+                        # Use HTML line breaks for email compatibility
+                        message = f"{message.rstrip()}<br><br>{content}"
+                    else:
+                        # If either is empty, just use the non-empty one
+                        message = message or content
+
+            return message, message_subject
+
+        except KeyError as e:
+            raise RuntimeError(f"Unsupported configuration - subject: {subject_lower}, event: {event_lower}, error: {str(e)}")
+        except ValueError as e:
+            raise RuntimeError(f"Invalid message format - error: {str(e)}")
 
     async def send_in_app_notification(
         self, receiver_id: str, subject: str, event: str, properties: dict = None