import requests

UA = {"User-Agent": "HF-Space-Trip-Planner/1.0 (contact: example@example.com)"}

def geocode_city(city: str):
    url = "https://nominatim.openstreetmap.org/search"
    params = {"q": city, "format": "json", "limit": 1}
    try:
        r = requests.get(url, params=params, headers=UA, timeout=20)
        r.raise_for_status()
        data = r.json()
        if not data:
            return None
        j = data[0]
        return {"lat": float(j["lat"]), "lon": float(j["lon"])}
    except Exception:
        return None