import os, requests

def send_ntfy_notification(title, message, click_url=None):
    topic = os.getenv("NTFY_TOPIC", "").strip()
    if not topic:
        return False
    server = os.getenv("NTFY_SERVER", "https://ntfy.sh").rstrip("/")
    headers = {"Title": title, "Priority": "high", "Tags": "calendar,question"}
    if click_url:
        headers["Click"] = click_url
    try:
        r = requests.post(f"{server}/{topic}", data=message.encode("utf-8"), headers=headers, timeout=8)
        r.raise_for_status()
        return True
    except requests.RequestException:
        return False