// Free OSM Nominatim geocoder — replaces Google Places Autocomplete /
// react-geocode across the console. No API key required. Nominatim's usage
// policy caps the public endpoint at ~1 req/sec; Astryx's `Typeahead`
// debounces queries internally (see `debounceMs` at each call site) and
// `createAddressSearchSource` aborts any still-in-flight request whenever a
// newer query supersedes it.
const NOMINATIM_SEARCH_URL = 'https://nominatim.openstreetmap.org/search';

// Builds a Google-Places-shaped `address_components` array (each entry
// `{ long_name, short_name, types: [] }`) from Nominatim's flat `address`
// object, so existing call sites' `place.address_components.forEach(...)`
// type-switch parsing keeps working unchanged.
const buildAddressComponents = (addr = {}) => {
  const components = [];
  const push = (longName, types) => {
    if (longName) components.push({ long_name: longName, short_name: longName, types });
  };
  push(addr.house_number, ['street_number']);
  push(addr.road || addr.pedestrian, ['route']);
  push(addr.suburb || addr.neighbourhood || addr.quarter, ['sublocality_level_1', 'sublocality']);
  push(addr.city_district || addr.county, ['administrative_area_level_3']);
  push(addr.city || addr.town || addr.village, ['locality']);
  push(addr.state, ['administrative_area_level_1']);
  push(addr.country, ['country']);
  push(addr.postcode, ['postal_code']);
  return components;
};

// Shapes a Nominatim result close enough to a Google Places `place` object
// (name, formatted_address, geometry.location.lat()/lng(), address_components)
// that call sites only needed mechanical edits, not rewrites, when swapping
// off Google.
export const toPlace = (result) => ({
  formatted_address: result.display_name,
  name: result.display_name?.split(',')[0] || '',
  geometry: {
    location: {
      lat: () => parseFloat(result.lat),
      lng: () => parseFloat(result.lon)
    }
  },
  address_components: buildAddressComponents(result.address)
});

const buildParams = (query, bias) => {
  const params = new URLSearchParams({ q: query, format: 'json', addressdetails: '1', limit: '5' });
  if (bias?.lat && bias?.lng) {
    const d = 0.5; // ~55km box around the operator's zone — soft bias, not a hard filter
    params.set('viewbox', `${bias.lng - d},${bias.lat + d},${bias.lng + d},${bias.lat - d}`);
  }
  return params;
};

// Builds a `SearchSource` for Astryx's `<Typeahead searchSource={...} />` —
// each result is `{ id, label, auxiliaryData }` where `auxiliaryData` is the
// `toPlace`-shaped object call sites parse via `address_components`.
export function createAddressSearchSource({ bias } = {}) {
  let controller = null;
  return {
    async search(query) {
      if (!query) return [];
      controller?.abort();
      controller = new AbortController();
      try {
        const params = buildParams(query, bias);
        const res = await fetch(`${NOMINATIM_SEARCH_URL}?${params.toString()}`, {
          headers: { Accept: 'application/json' },
          signal: controller.signal
        });
        if (!res.ok) return [];
        const results = await res.json();
        return (results || []).map((result) => ({
          id: String(result.place_id),
          label: result.display_name,
          auxiliaryData: toPlace(result)
        }));
      } catch (err) {
        if (err.name === 'AbortError') return [];
        console.error('address search error:', err);
        return [];
      }
    },
    bootstrap() {
      return [];
    },
    cancel() {
      controller?.abort();
    }
  };
}