selectProxy method

Implementation

@override
Proxy selectProxy(List<Proxy> proxies) {
  if (proxies.isEmpty) {
    throw ArgumentError('Proxy list cannot be empty');
  }

  // Group proxies by country
  final proxiesByCountry = <String?, List<Proxy>>{};
  final countryCodes = <String?>[];

  for (final proxy in proxies) {
    final countryCode = proxy.countryCode;
    if (!proxiesByCountry.containsKey(countryCode)) {
      proxiesByCountry[countryCode] = [];
      countryCodes.add(countryCode);
    }
    proxiesByCountry[countryCode]!.add(proxy);
  }

  // Sort country codes for deterministic behavior
  countryCodes.sort((a, b) {
    if (a == null) return 1;
    if (b == null) return -1;
    return a.compareTo(b);
  });

  if (countryCodes.isEmpty) {
    return proxies.first;
  }

  // Get the current country code
  final countryIndex = _currentCountryIndex % countryCodes.length;
  final countryCode = countryCodes[countryIndex];

  // Get the proxies for the current country
  final countryProxies = proxiesByCountry[countryCode] ?? [];
  if (countryProxies.isEmpty) {
    // Move to the next country
    _currentCountryIndex = (_currentCountryIndex + 1) % countryCodes.length;
    return selectProxy(proxies);
  }

  // Get the current proxy
  final proxyIndex = _currentProxyIndex % countryProxies.length;
  final proxy = countryProxies[proxyIndex];

  // Move to the next proxy in the current country
  _currentProxyIndex = (_currentProxyIndex + 1) % countryProxies.length;

  // If we've gone through all proxies in the current country, move to the next country
  if (_currentProxyIndex == 0) {
    _currentCountryIndex = (_currentCountryIndex + 1) % countryCodes.length;
  }

  return proxy;
}