Update main.py

main.py

@@ -225,19 +225,37 @@ def sc_request(method: str, path: str, email: str, password: str, *,
 # -----------------------------------------------------------------------------
 # Temporal helpers
 # -----------------------------------------------------------------------------
+# -----------------------------------------------------------------------------
+# Timezone Configuration (fix for "_TZ is not defined")
+# -----------------------------------------------------------------------------
+import os
+import pandas as pd
+
+# Canonical timezone for Brave Retail Insights
+TZ = os.getenv("APP_TZ", "Africa/Harare")
+
+# Backward-compatible alias for older references
+_TZ = TZ
+
 def now_harare() -> pd.Timestamp:
-    return pd.Timestamp.now(tz=_TZ)
+    """Return the current timestamp in Harare timezone."""
+    return pd.Timestamp.now(tz=TZ)
 
-def week_bounds_from(ts: pd.Timestamp) -> Tuple[pd.Timestamp, pd.Timestamp]:
-    monday = ts.tz_convert(_TZ).normalize() - pd.Timedelta(days=ts.weekday())
+def week_bounds_from(ts: pd.Timestamp) -> tuple[pd.Timestamp, pd.Timestamp]:
+    """Return Monday–Sunday bounds for the given timestamp."""
+    monday = ts.tz_convert(TZ).normalize() - pd.Timedelta(days=ts.weekday())
     sunday = monday + pd.Timedelta(days=6, hours=23, minutes=59, seconds=59)
     return monday, sunday
 
-def this_month_bounds(ts: pd.Timestamp) -> Tuple[pd.Timestamp, pd.Timestamp]:
+def this_month_bounds(ts: pd.Timestamp) -> tuple[pd.Timestamp, pd.Timestamp]:
+    """Return start and end of the current month."""
     first_this = ts.normalize().replace(day=1)
-    first_next = first_this.replace(year=first_this.year + 1, month=1) if first_this.month == 12 else first_this.replace(month=first_this.month + 1)
-    last_this = first_next - pd.Timedelta(seconds=1)
+    next_month = first_this.replace(
+        year=first_this.year + 1, month=1
+    ) if first_this.month == 12 else first_this.replace(month=first_this.month + 1)
+    last_this = next_month - pd.Timedelta(seconds=1)
     return first_this, last_this
+    
 
 def period_to_bounds(period: str) -> Tuple[pd.Timestamp, pd.Timestamp, str]:
     p = (period or "week").strip().lower()