Jun 29 - Implement auto reminder 45 min before user's shift end if not finish checking websites

routes/admin_shifts.py

@@ -118,7 +118,7 @@ def edit(shift_id):
     return redirect(url_for("admin_shifts.shifts_list"))
 
 
-REMINDER_WINDOW_MIN = 40
+REMINDER_WINDOW_MIN = 45
 
 
 def _fmt_time(t) -> str:
@@ -144,6 +144,11 @@ def do_send_incomplete_reminders(triggered_by_user_id=None) -> dict:
             skipped += 1
             continue
 
+        # Atomically claim this reminder slot before sending.
+        # If another worker already claimed it (rowcount == 0), skip to avoid duplicates.
+        if not record_shift_reminder(row["user_id"], row["shift_id"]):
+            continue
+
         end_str    = _fmt_time(row["end_time"])
         site_lines = "\n".join(
             f"  • {s['name']} — {s['url']}" for s in row["unchecked_sites"]
@@ -163,7 +168,6 @@ def do_send_incomplete_reminders(triggered_by_user_id=None) -> dict:
                 f"Action required — complete your shift checks by {end_str}",
                 body,
             )
-            record_shift_reminder(row["user_id"], row["shift_id"])
             log_action(
                 triggered_by_user_id, "SHIFT_INCOMPLETE_REMINDER", "shifts", row["shift_id"],
                 f"Reminder sent to {row['username']} ({row['email']}): "
@@ -180,7 +184,7 @@ def do_send_incomplete_reminders(triggered_by_user_id=None) -> dict:
 @admin_shifts_bp.route("/send-incomplete-reminders", methods=["POST"])
 @admin_required
 def send_incomplete_reminders():
-    """Manual trigger: email staff with incomplete checks in shifts ending within 40 min."""
+    """Manual trigger: email staff with incomplete checks in shifts ending within 45 min."""
     result = do_send_incomplete_reminders(triggered_by_user_id=session["user"]["id"])
 
     if result["total"] == 0: