package com.atlassian.httpclient.apache.httpcomponents.proxy;
   
   import com.atlassian.fugue.Option;
   import com.atlassian.fugue.Options;
   import com.google.common.collect.Iterables;
   import com.google.common.collect.Lists;
   import org.apache.commons.lang3.StringUtils;
   import org.apache.http.HttpHost;
   import org.apache.http.auth.AuthScope;
  import org.apache.http.auth.Credentials;
  import org.apache.http.auth.NTCredentials;
  import org.apache.http.auth.UsernamePasswordCredentials;
  
  import java.net.ProxySelector;
  
  /**
   * Proxy configuration set with system properties.
   */
  @SuppressWarnings("StaticPseudoFunctionalStyleMethod")
  public class SystemPropertiesProxyConfig extends ProxyConfig {
      private static final Iterable<String> SUPPORTED_SCHEMAS = Lists.newArrayList("http", "https");
  
      Iterable<HttpHost> getProxyHosts() {
          return Options.flatten(Options.filterNone(
                  Iterables.transform(SUPPORTED_SCHEMAS, SystemPropertiesProxyConfig::getProxy)));
      }
  
      @SuppressWarnings("ConstantConditions")
      @Override
      public Iterable<AuthenticationInfo> getAuthenticationInfo() {
          return Iterables.transform(getProxyHosts(), httpHost -> {
              final AuthScope authScope = new AuthScope(httpHost);
              final Option<Credentials> credentials = credentialsForScheme(httpHost.getSchemeName());
              return new AuthenticationInfo(authScope, credentials);
          });
      }
  
      @Override
      public ProxySelector toProxySelector() {
          // the default ProxySelector will just do the right thing
          return ProxySelector.getDefault();
      }
  
      private static Option<HttpHost> getProxy(final String schemeName) {
          String proxyHost = System.getProperty(schemeName + ".proxyHost");
          if (proxyHost != null) {
              return Option.some(new HttpHost(proxyHost, Integer.parseInt(System.getProperty(schemeName + ".proxyPort")), schemeName));
          } else {
              return Option.none();
          }
      }
  
      private static Option<Credentials> credentialsForScheme(final String schemeName) {
          final String username = System.getProperty(schemeName + ".proxyUser");
          if (username != null) {
              final String proxyPassword = System.getProperty(schemeName + ".proxyPassword");
              final String proxyAuth = System.getProperty(schemeName + ".proxyAuth");
              if (proxyAuth == null || proxyAuth.equalsIgnoreCase("basic")) {
                  return Option.<Credentials>some(new UsernamePasswordCredentials(username, proxyPassword));
              } else if (proxyAuth.equalsIgnoreCase("digest") || proxyAuth.equalsIgnoreCase("ntlm")) {
                  String ntlmDomain = System.getProperty(schemeName + ".proxyNtlmDomain");
                  String ntlmWorkstation = System.getProperty(schemeName + ".proxyNtlmWorkstation");
                  return Option.<Credentials>some(new NTCredentials(username, proxyPassword,
                          StringUtils.defaultString(ntlmWorkstation), StringUtils.defaultString(ntlmDomain)));
              } else {
                  return Option.none();
              }
          } else {
              return Option.none();
          }
      }
  
  }