import os
from dataclasses import dataclass

from cnet import HttpError, as_dict, as_float, as_str, fetch_json


class GeoError(Exception): ...


@dataclass(frozen=True)
class Geo:
    city: str
    lat: float | None
    lon: float | None


def _parse_float(text: str) -> float | None:
    try:
        return float(text)
    except ValueError:
        return None


def _get_coords(data: dict[str, object]) -> tuple[float, float] | None:
    loc = data.get("loc")
    if isinstance(loc, str):
        parts = loc.split(",", 1)
        if len(parts) == 2:
            lat = _parse_float(parts[0])
            lon = _parse_float(parts[1])
            if lat is not None and lon is not None:
                return lat, lon
    lat = as_float(data.get("latitude"))
    lon = as_float(data.get("longitude"))
    if lat is not None and lon is not None:
        return lat, lon
    return None


def get_geo() -> Geo:
    url = os.getenv("GEO_API_URL", "https://ipinfo.io/json")

    try:
        raw = fetch_json(url)
        data = as_dict(raw)
        city = as_str(data.get("city")) or as_str(data.get("cityName"))
        coords = _get_coords(data)
        if not city or coords is None:
            raise ValueError("city not found")
        return Geo(city=city, lat=coords[0], lon=coords[1])
    except (HttpError, ValueError) as exc:
        fallback = os.getenv("GEO_API_FALLBACK_CITY", "").strip()
        if fallback:
            print(f"fallback city: {fallback}")
            return Geo(city=fallback, lat=None, lon=None)
        raise GeoError(f"No geo: {exc}") from exc