package com.atlassian.httpclient.apache.httpcomponents.proxy;
   
   import com.atlassian.fugue.Effect;
   import com.atlassian.fugue.Option;
   import com.atlassian.httpclient.api.factory.HttpClientOptions;
   import com.google.common.base.Predicate;
   import com.google.common.collect.Iterables;
   import org.apache.http.auth.AuthScope;
   import org.apache.http.auth.Credentials;
  import org.apache.http.client.CredentialsProvider;
  import org.apache.http.impl.client.SystemDefaultCredentialsProvider;
  
  import static com.atlassian.httpclient.apache.httpcomponents.proxy.ProxyConfig.AuthenticationInfo;
  
  /**
   * Configuration of credentials for proxy.
   */
  public class ProxyCredentialsProvider implements CredentialsProvider {
      private final SystemDefaultCredentialsProvider delegate;
  
      private ProxyCredentialsProvider(final SystemDefaultCredentialsProvider delegate) {
          this.delegate = delegate;
      }
  
      public static Option<ProxyCredentialsProvider> build(final HttpClientOptions options) {
          final Iterable<AuthenticationInfo> authenticationInfos = Iterables.filter(
                  ProxyConfigFactory.getProxyAuthentication(options),
                  authenticationInfo -> authenticationInfo.getCredentials().isDefined());
  
          return Iterables.isEmpty(authenticationInfos) ? Option.<ProxyCredentialsProvider>none() : Option.some(createCredentialProvider(authenticationInfos));
      }
  
      private static ProxyCredentialsProvider createCredentialProvider(final Iterable<AuthenticationInfo> authenticationInfos) {
          final SystemDefaultCredentialsProvider credentialsProvider = new SystemDefaultCredentialsProvider();
  
          for (final AuthenticationInfo authenticationInfo : authenticationInfos) {
              authenticationInfo.getCredentials().foreach(credentials ->
                      credentialsProvider.setCredentials(authenticationInfo.getAuthScope(), credentials));
          }
  
          return new ProxyCredentialsProvider(credentialsProvider);
      }
  
      @Override
      public void setCredentials(final AuthScope authscope, final Credentials credentials) {
          delegate.setCredentials(authscope, credentials);
      }
  
      @Override
      public Credentials getCredentials(final AuthScope authscope) {
          return delegate.getCredentials(authscope);
      }
  
      @Override
      public void clear() {
          delegate.clear();
      }
  }