import { fetchJson } from "./http";
import type { Place } from "./types";

/**
 * Turns a city name into coordinates (and coordinates back into a name).
 *
 * OpenWeather's geocoder is used when its key is set; otherwise we fall back
 * to Open-Meteo's free geocoder so search still works with zero keys.
 */

interface OwmPlace {
  name: string;
  state?: string;
  country: string;
  lat: number;
  lon: number;
}

interface OpenMeteoGeocodeResponse {
  results?: { name: string; admin1?: string; country_code: string; latitude: number; longitude: number }[];
}

const OWM_GEO = "https://api.openweathermap.org/geo/1.0";

function fromOwm(place: OwmPlace): Place {
  return { name: place.name, region: place.state, country: place.country, lat: place.lat, lon: place.lon };
}

export async function searchPlaces(query: string): Promise<Place[]> {
  const key = process.env.OPENWEATHER_API_KEY?.trim();
  const q = encodeURIComponent(query.slice(0, 120));

  if (key) {
    const places = await fetchJson<OwmPlace[]>(`${OWM_GEO}/direct?q=${q}&limit=5&appid=${key}`, "OpenWeather");
    return places.map(fromOwm);
  }

  const data = await fetchJson<OpenMeteoGeocodeResponse>(
    `https://geocoding-api.open-meteo.com/v1/search?name=${q}&count=5`,
    "Open-Meteo",
  );
  return (data.results ?? []).map((r) => ({
    name: r.name,
    region: r.admin1,
    country: r.country_code,
    lat: r.latitude,
    lon: r.longitude,
  }));
}

/** Used by "Use my location". Without an OpenWeather key we can't name the spot. */
export async function reversePlace(lat: number, lon: number): Promise<Place> {
  const fallback: Place = { name: "Your location", lat, lon };
  const key = process.env.OPENWEATHER_API_KEY?.trim();
  if (!key) return fallback;

  const places = await fetchJson<OwmPlace[]>(`${OWM_GEO}/reverse?lat=${lat}&lon=${lon}&limit=1&appid=${key}`, "OpenWeather");
  // Keep the user's exact coordinates rather than the city centre's.
  return places[0] ? { ...fromOwm(places[0]), lat, lon } : fallback;
}