Unset existing default before setting new one

backend/app/db/functions/recommendations_functions.py

@@ -646,6 +646,40 @@ def get_scenario(scenario_id: int) -> Optional[ScenarioModel]:
         return session_any.exec(stmt).scalar_one_or_none()
 
 
+def get_default_plan_ids_for_property(property_id: int) -> List[int]:
+    # This should in reality always return exactly 1 ID, but there's currently
+    # no database constraint to enforce that, so account for 0 or >1
+    stmt = select(PlanModel.id).where(
+        PlanModel.property_id == property_id and PlanModel.is_default
+    )
+    with db_read_session() as session:
+        session_any: Any = session  # Typehint as Any to satisfy Pylance...
+        return session_any.exec(stmt).scalars().all()
+
+
+def set_plan_and_scenario_default(plan_id: int, default: bool) -> bool:
+    with db_session() as session:
+        plan: PlanModel = session.get(PlanModel, plan_id)
+        if not plan:
+            return False
+
+        scenario_id = plan.scenario_id
+
+        plan_mapper: Mapper[Any] = inspect(PlanModel)
+        scenario_mapper: Mapper[Any] = inspect(ScenarioModel)
+
+        plan_mappings: List[Dict[str, Any]] = [{"id": plan.id, "is_default": default}]
+        scenario_mappings: List[Dict[str, Any]] = [
+            {"id": scenario_id, "is_default": default}
+        ]
+
+        session.bulk_update_mappings(plan_mapper, plan_mappings)
+        session.bulk_update_mappings(scenario_mapper, scenario_mappings)
+        session.commit()
+
+        return True
+
+
 def bulk_update_plans(
     plan_models: List[PlanModel],
     scenario_models: List[ScenarioModel],

backend/categorisation/local_handler/invoke_local_lambda.py

@@ -10,7 +10,7 @@ payload = {
             "body": json.dumps(
                 {
                     "portfolio_id": 556,
-                    "plans_to_consider": [],
+                    "plans_to_consider": [1589319, 1589320],
                     "plan_priority_order": [],
                 }
             )

backend/categorisation/processor.py

@@ -3,9 +3,11 @@ from typing import Dict, List, Optional
 
 from backend.app.db.functions.recommendations_functions import (
     bulk_update_plans,
+    get_default_plan_ids_for_property,
     get_plans_by_ids,
     get_plans_by_portfolio_id,
     get_scenarios_by_portfolio_id,
+    set_plan_and_scenario_default,
 )
 from backend.app.db.models.recommendations import PlanModel, ScenarioModel
 from backend.app.domain.classes.plan import Plan
@@ -26,15 +28,23 @@ def process_portfolio(
 
     plans_by_property: Dict[int, List[Plan]] = _group_plans_by_property(plans)
 
-    for uprn, property_plans in plans_by_property.items():
+    for property_id, property_plans in plans_by_property.items():
 
         if not property_plans:
-            raise ValueError(f"No plans for property {uprn}")
+            raise ValueError(f"No plans for property {property_id}")
 
         cheapest_plan = choose_cheapest_relevant_plan(
             property_plans, plan_priority_order
         )
-        _update_default_flags(property_plans, cheapest_plan)
+
+        # Unset existing default(s) in case they are outside the plans to consider
+        default_plan_ids: List[int] = get_default_plan_ids_for_property(property_id)
+        for id in default_plan_ids:
+            set_plan_and_scenario_default(id, False)
+
+        _update_default_flags(
+            property_plans, cheapest_plan
+        )  # TODO: we have already unset existing default(s), so this method can probably be a bit simpler now
 
 
 def choose_cheapest_relevant_plan(