Add barebone session resumption feature

apps/cic-ussd/cic_ussd/operations.py

@@ -14,7 +14,7 @@ from cic_ussd.db.models.user import User
 from cic_ussd.db.models.ussd_session import UssdSession
 from cic_ussd.db.models.task_tracker import TaskTracker
 from cic_ussd.menu.ussd_menu import UssdMenu
-from cic_ussd.processor import custom_display_text, process_request
+from cic_ussd.processor import custom_display_text, process_request, retrieve_most_recent_ussd_session
 from cic_ussd.redis import InMemoryStore
 from cic_ussd.session.ussd_session import UssdSession as InMemoryUssdSession
 from cic_ussd.validator import check_known_user, validate_response_type
@@ -60,7 +60,8 @@ def create_ussd_session(
         phone: str,
         service_code: str,
         user_input: str,
-        current_menu: str) -> InMemoryUssdSession:
+        current_menu: str,
+        session_data: Optional[dict] = None) -> InMemoryUssdSession:
     """
     Creates a new ussd session
     :param external_session_id: Session id value provided by AT
@@ -73,6 +74,8 @@ def create_ussd_session(
     :type user_input: str
     :param current_menu: Menu name that is currently being displayed on the ussd session
     :type current_menu: str
+    :param session_data: Any additional data that was persisted during the user's interaction with the system.
+    :type session_data: dict.
     :return: ussd session object
     :rtype: Session
     """
@@ -81,7 +84,8 @@ def create_ussd_session(
         msisdn=phone,
         user_input=user_input,
         state=current_menu,
-        service_code=service_code
+        service_code=service_code,
+        session_data=session_data
     )
     return session
 
@@ -126,7 +130,9 @@ def create_or_update_session(
             phone=phone,
             service_code=service_code,
             user_input=user_input,
-            current_menu=current_menu)
+            current_menu=current_menu,
+            session_data=session_data
+        )
     return ussd_session
 
 
@@ -338,7 +344,19 @@ def process_menu_interaction_requests(chain_str: str,
                 user_input=user_input
             )
 
+        last_ussd_session = retrieve_most_recent_ussd_session(phone_number=user.phone_number)
+
+        if last_ussd_session:
             # create or update the ussd session as appropriate
+            ussd_session = create_or_update_session(
+                external_session_id=external_session_id,
+                phone=phone_number,
+                service_code=service_code,
+                user_input=user_input,
+                current_menu=current_menu.get('name'),
+                session_data=last_ussd_session.session_data
+            )
+        else:
             ussd_session = create_or_update_session(
                 external_session_id=external_session_id,
                 phone=phone_number,

apps/cic-ussd/cic_ussd/processor.py

@@ -6,7 +6,7 @@ from typing import Optional
 
 # third party imports
 import celery
-from cic_types.models.person import Person
+from sqlalchemy import desc
 from tinydb.table import Document
 
 # local imports
@@ -315,6 +315,16 @@ def process_start_menu(display_key: str, user: User):
     )
 
 
+def retrieve_most_recent_ussd_session(phone_number: str) -> UssdSession:
+    # get last ussd session based on user phone number
+    last_ussd_session = UssdSession.session\
+        .query(UssdSession)\
+        .filter_by(msisdn=phone_number)\
+        .order_by(desc(UssdSession.created))\
+        .first()
+    return last_ussd_session
+
+
 def process_request(user_input: str, user: User, ussd_session: Optional[dict] = None) -> Document:
     """This function assesses a request based on the user from the request comes, the session_id and the user's
     input. It determines whether the request translates to a return to an existing session by checking whether the
@@ -337,7 +347,23 @@ def process_request(user_input: str, user: User, ussd_session: Optional[dict] =
             return UssdMenu.find_by_name(name=successive_state)
     else:
         if user.has_valid_pin():
+            last_ussd_session = retrieve_most_recent_ussd_session(phone_number=user.phone_number)
+
+            key = create_cached_data_key(
+                identifier=blockchain_address_to_metadata_pointer(blockchain_address=user.blockchain_address),
+                salt='cic.person'
+            )
+            user_metadata = get_cached_data(key=key)
+
+            if last_ussd_session:
+                # get last state
+                last_state = last_ussd_session.state
+                logg.debug(f'LAST USSD SESSION STATE: {last_state}')
+                # if last state is account_creation_prompt and metadata exists, show start menu
+                if last_state == 'account_creation_prompt' and user_metadata is not None:
                     return UssdMenu.find_by_name(name='start')
+                else:
+                    return UssdMenu.find_by_name(name=last_state)
         else:
             if user.failed_pin_attempts >= 3 and user.get_account_status() == AccountStatus.LOCKED.name:
                 return UssdMenu.find_by_name(name='exit_pin_blocked')