geocoding.js

const https = require('https');

const GEOCODING_TIMEOUT = 5000;
const NOMINATIM_BASE = 'https://nominatim.openstreetmap.org';

function requestJson(url) {
  return new Promise((resolve) => {
    const req = https.get(
      url,
      {
        headers: {
          'Accept-Language': 'it',
          'User-Agent': 'MyZubster/1.0 (test@myzubster.com)',
        },
      },
      (res) => {
        let body = '';
        res.setEncoding('utf8');
        res.on('data', (chunk) => {
          body += chunk;
        });
        res.on('end', () => {
          if (res.statusCode < 200 || res.statusCode >= 300) {
            resolve(null);
            return;
          }
          try {
            resolve(JSON.parse(body));
          } catch (_) {
            resolve(null);
          }
        });
      }
    );
    req.setTimeout(GEOCODING_TIMEOUT, () => {
      req.destroy();
      resolve(null);
    });
    req.on('error', () => {
      resolve(null);
    });
  });
}

async function geocodeAddress(address) {
  if (!address || address.trim() === '') return null;
  const url =
    NOMINATIM_BASE +
    '/search?q=' +
    encodeURIComponent(address) +
    '&format=json&limit=1&addressdetails=1';
  const results = await requestJson(url);
  if (!Array.isArray(results) || results.length === 0) return null;
  const first = results[0];
  const lat = parseFloat(first.lat);
  const lng = parseFloat(first.lon);

  if (
    !Number.isFinite(lat) ||
    !Number.isFinite(lng) ||
    lat < -90 ||
    lat > 90 ||
    lng < -180 ||
    lng > 180
  ) {
    return null;
  }

  return {
    lat,
    lng,
    displayName: first.display_name || '',
    osmId: first.osm_id || null,
    osmType: first.osm_type || null,
    neighborhood:
      (first.address && (first.address.suburb || first.address.neighbourhood)) || '',
    city:
      (first.address &&
        (first.address.city ||
          first.address.town ||
          first.address.village ||
          first.address.municipality)) ||
      '',
  };
}

async function reverseGeocode(lat, lng) {
  if (lat === undefined || lng === undefined) return null;
  const url =
    NOMINATIM_BASE +
    '/reverse?lat=' +
    lat +
    '&lon=' +
    lng +
    '&format=json&addressdetails=1';
  const data = await requestJson(url);
  if (!data || data.error) return null;
  return {
    displayName: data.display_name || '',
    address: data.display_name || '',
    neighborhood:
      (data.address && (data.address.suburb || data.address.neighbourhood)) || '',
    city:
      (data.address &&
        (data.address.city ||
          data.address.town ||
          data.address.village ||
          data.address.municipality)) ||
      '',
  };
}

module.exports = { geocodeAddress, reverseGeocode };