package org.eclipse.aether.transport.http;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   * 
   *  http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import java.net.InetAddress;
  import java.net.UnknownHostException;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  
  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 org.apache.http.client.CredentialsProvider;
  import org.apache.http.impl.client.BasicCredentialsProvider;
  import org.eclipse.aether.repository.AuthenticationContext;
  
  /**
   * Credentials provider that defers calls into the auth context until authentication is actually requested.
   */
  final class DeferredCredentialsProvider
      implements CredentialsProvider
  {
  
      private final CredentialsProvider delegate;
  
      private final Map<AuthScope, Factory> factories;
  
      DeferredCredentialsProvider()
      {
          delegate = new BasicCredentialsProvider();
          factories = new HashMap<>();
      }
  
      public void setCredentials( AuthScope authScope, Factory factory )
      {
          factories.put( authScope, factory );
      }
  
      @Override
      public void setCredentials( AuthScope authScope, Credentials credentials )
      {
          delegate.setCredentials( authScope, credentials );
      }
  
      @Override
      public Credentials getCredentials( AuthScope authScope )
      {
          synchronized ( factories )
          {
              for ( Iterator<Map.Entry<AuthScope, Factory>> it = factories.entrySet().iterator(); it.hasNext(); )
              {
                  Map.Entry<AuthScope, Factory> entry = it.next();
                  if ( authScope.match( entry.getKey() ) >= 0 )
                  {
                      it.remove();
                      delegate.setCredentials( entry.getKey(), entry.getValue().newCredentials() );
                  }
              }
          }
          return delegate.getCredentials( authScope );
      }
  
      @Override
      public void clear()
      {
          delegate.clear();
      }
  
      interface Factory
      {
  
          Credentials newCredentials();
  
      }
  
      static class BasicFactory
          implements Factory
      {
  
          private final AuthenticationContext authContext;
 
         BasicFactory( AuthenticationContext authContext )
         {
             this.authContext = authContext;
         }
 
         @Override
         public Credentials newCredentials()
         {
             String username = authContext.get( AuthenticationContext.USERNAME );
             if ( username == null )
             {
                 return null;
             }
             String password = authContext.get( AuthenticationContext.PASSWORD );
             return new UsernamePasswordCredentials( username, password );
         }
 
     }
 
     static class NtlmFactory
         implements Factory
     {
 
         private final AuthenticationContext authContext;
 
         NtlmFactory( AuthenticationContext authContext )
         {
             this.authContext = authContext;
         }
 
         @Override
         public Credentials newCredentials()
         {
             String username = authContext.get( AuthenticationContext.USERNAME );
             if ( username == null )
             {
                 return null;
             }
             String password = authContext.get( AuthenticationContext.PASSWORD );
             String domain = authContext.get( AuthenticationContext.NTLM_DOMAIN );
             String workstation = authContext.get( AuthenticationContext.NTLM_WORKSTATION );
 
             if ( domain == null )
             {
                 int backslash = username.indexOf( '\\' );
                 if ( backslash < 0 )
                 {
                     domain = guessDomain();
                 }
                 else
                 {
                     domain = username.substring( 0, backslash );
                     username = username.substring( backslash + 1 );
                 }
             }
             if ( workstation == null )
             {
                 workstation = guessWorkstation();
             }
 
             return new NTCredentials( username, password, workstation, domain );
         }
 
         private static String guessDomain()
         {
             return safeNtlmString( System.getProperty( "http.auth.ntlm.domain" ), System.getenv( "USERDOMAIN" ) );
         }
 
         private static String guessWorkstation()
         {
             String localHost = null;
             try
             {
                 localHost = InetAddress.getLocalHost().getHostName();
             }
             catch ( UnknownHostException e )
             {
                 // well, we have other options to try
             }
             return safeNtlmString( System.getProperty( "http.auth.ntlm.host" ), System.getenv( "COMPUTERNAME" ),
                                    localHost );
         }
 
         private static String safeNtlmString( String... strings )
         {
             for ( String string : strings )
             {
                 if ( string != null )
                 {
                     return string;
                 }
             }
             // avoid NPE from httpclient and trigger proper auth failure instead
             return "";
         }
 
     }
 
 }