/// Build-time configuration, supplied with `--dart-define-from-file=env.json`.
///
/// Every value has a working default, so the app builds and runs with no
/// `env.json` at all: it starts in demo mode against bundled mock frames, with
/// the offline map style and Google's test ad units. That keeps the repository
/// free of secrets and keeps a fresh clone runnable.
///
/// Values are `const` reads of `String.fromEnvironment` so they are inlined and
/// tree-shaken; they cannot be read from a file at run time.
library;

class Env {
  const Env._();

  /// Which region config to load from `assets/regions/<id>.json`.
  static const String regionId = String.fromEnvironment(
    'REGION_ID',
    defaultValue: 'piemonte',
  );

  /// MapLibre style URL for the base map.
  ///
  /// Empty means no key is configured, and [hasMapStyle] is false: the app
  /// falls back to a minimal style bundled in assets so development and tests
  /// work offline.
  static const String mapStyleUrl = String.fromEnvironment('MAP_STYLE_URL');

  static bool get hasMapStyle => mapStyleUrl.isNotEmpty;

  /// Base URL of the radar `manifest.json` published by our worker.
  ///
  /// Empty forces the mock radar source regardless of [radarSource].
  static const String radarManifestUrl = String.fromEnvironment(
    'RADAR_MANIFEST_URL',
  );

  /// Radar adapter override: `mock`, `dpc` or `arpa`.
  ///
  /// Empty means "use whatever the region config says".
  static const String radarSource = String.fromEnvironment('RADAR_SOURCE');

  /// Contact address embedded in the MET Norway User-Agent.
  ///
  /// MET Norway blocks generic User-Agent strings, so forecasts are disabled
  /// rather than attempted when this is empty — see [hasForecastContact].
  static const String metnoUserAgentContact = String.fromEnvironment(
    'METNO_USER_AGENT_CONTACT',
  );

  static bool get hasForecastContact => metnoUserAgentContact.isNotEmpty;

  /// AdMob identifiers. Empty means Google's test units are used.
  static const String admobAppId = String.fromEnvironment('ADMOB_APP_ID');
  static const String admobBannerUnitId = String.fromEnvironment(
    'ADMOB_BANNER_UNIT_ID',
  );

  static bool get hasAdMobConfig =>
      admobAppId.isNotEmpty && admobBannerUnitId.isNotEmpty;

  /// True when nothing is configured and the app is running entirely on
  /// bundled data. Surfaced in the UI so demo frames are never mistaken for a
  /// real forecast.
  static bool get isDemoMode => radarManifestUrl.isEmpty;
}