/// Application-level runtime configuration.
class AppConfig {
  AppConfig._();

  static const String _defaultBaseUrl = String.fromEnvironment(
    'BACKEND_BASE_URL',
    defaultValue: 'https://api.example.com',
  );

  static String? _baseUrlOverride;

  static const String _defaultSentryDsn = String.fromEnvironment(
    'SENTRY_DSN',
    defaultValue:
        'https://97fb0a56bc35440fba0ba139dc3b1ccc@bugs.zuzo.ch/2',
  );

  static const String _defaultSentryEnvironment = String.fromEnvironment(
    'SENTRY_ENVIRONMENT',
    defaultValue: '',
  );

  static const String _defaultSentryRelease = String.fromEnvironment(
    'SENTRY_RELEASE',
    defaultValue: '',
  );

  /// Returns the configured backend base URL.
  static String get backendBaseUrl {
    final String? override = _baseUrlOverride;
    if (override != null && override.trim().isNotEmpty) {
      return override.trim();
    }
    return _defaultBaseUrl;
  }

  /// Enables fake backend implementation for local/offline development.
  static bool get useFakeBackend =>
      const bool.fromEnvironment('USE_FAKE_BACKEND', defaultValue: true);

  /// Enables Hive local persistence store instead of shared_preferences.
  static bool get useHiveLocalDb =>
      const bool.fromEnvironment('USE_HIVE_LOCAL_DB', defaultValue: true);

  /// Enables periodic startup/resume sync triggers while authenticated.
  static bool get enableBackgroundSync =>
      const bool.fromEnvironment('ENABLE_BACKGROUND_SYNC', defaultValue: false);

  /// Enables local notifications runtime for reminder delivery.
  static bool get enableLocalNotifications => const bool.fromEnvironment(
    'ENABLE_LOCAL_NOTIFICATIONS',
    defaultValue: true,
  );

  /// Enables inbound share-intake pipeline for WhatsApp text shares.
  static bool get enableWhatsAppShareIntake => const bool.fromEnvironment(
    'ENABLE_WHATSAPP_SHARE_INTAKE',
    defaultValue: true,
  );

  /// Interval used for periodic background sync ticks.
  static int get backgroundSyncIntervalSeconds => const int.fromEnvironment(
    'BACKGROUND_SYNC_INTERVAL_SECONDS',
    defaultValue: 180,
  );

  /// Sentry-compatible DSN for release crash/error reporting.
  static String get sentryDsn => _defaultSentryDsn.trim();

  /// Sentry environment label.
  static String get sentryEnvironment {
    final String configured = _defaultSentryEnvironment.trim();
    if (configured.isNotEmpty) {
      return configured;
    }
    return useFakeBackend ? 'development' : 'production';
  }

  /// Optional Sentry release identifier.
  static String? get sentryRelease {
    final String configured = _defaultSentryRelease.trim();
    if (configured.isEmpty) {
      return null;
    }
    return configured;
  }

  /// Runtime override for backend URL (e.g. local settings screen).
  static void overrideBackendBaseUrl(String? baseUrl) {
    _baseUrlOverride = baseUrl;
  }
}