Update usage_logging.py

usage_logging.py

@@ -273,6 +273,15 @@ def _expand_country_code(code: str) -> str:
         return "Unknown"
 
 
+def _is_meaningful_country(val: str) -> bool:
+    v = (val or "").strip().lower()
+    if not v:
+        return False
+    if v in {"unknown", "na", "n/a", "none", "null", "undefined"}:
+        return False
+    return True
+
+
 def rebuild_visits_rollup_from_event_files() -> str:
     """
     Rebuilds usage/visits.jsonl from immutable per-event JSON files in usage/events/.
@@ -363,9 +372,7 @@ def rebuild_visits_rollup_from_event_files() -> str:
 
         # Determine final_country / final_country_code
         if sid:
-            # New schema row: prefer existing event country if it’s meaningful,
-            # else fall back to session geo.
-            if evt_country and evt_country.lower() != "unknown":
+            if _is_meaningful_country(evt_country):
                 enriched["final_country"] = evt_country
                 enriched["final_country_code"] = evt_cc
                 enriched["final_country_source"] = evt.get("country_source") or "unknown"