/*
    * Copyright (C) 2013 4th Line GmbH, Switzerland
    *
    * The contents of this file are subject to the terms of either the GNU
    * Lesser General Public License Version 2 or later ("LGPL") or the
    * Common Development and Distribution License Version 1 or later
    * ("CDDL") (collectively, the "License"). You may not use this file
    * except in compliance with the License. See LICENSE.txt for more
    * information.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   */
  
  package org.fourthline.cling.android;
  
  import org.fourthline.cling.transport.impl.NetworkAddressFactoryImpl;
  import org.fourthline.cling.transport.spi.InitializationException;
  
  import java.lang.reflect.Field;
  import java.net.Inet4Address;
  import java.net.Inet6Address;
  import java.net.InetAddress;
  import java.net.NetworkInterface;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  /**
   * This factory tries to work around and patch some Android bugs.
   *
   * @author Michael Pujos
   * @author Christian Bauer
   */
  public class AndroidNetworkAddressFactory extends NetworkAddressFactoryImpl {
  
      final private static Logger log = Logger.getLogger(AndroidUpnpServiceConfiguration.class.getName());
  
      public AndroidNetworkAddressFactory(int streamListenPort) {
          super(streamListenPort);
      }
  
      @Override
      protected boolean requiresNetworkInterface() {
          return false;
      }
  
      @Override
      protected boolean isUsableAddress(NetworkInterface networkInterface, InetAddress address) {
          boolean result = super.isUsableAddress(networkInterface, address);
          if (result) {
              // TODO: Workaround Android DNS reverse lookup issue, still a problem on ICS+?
              // http://4thline.org/projects/mailinglists.html#nabble-td3011461
              String hostName = address.getHostAddress();
  
  	    Field field0 = null;
  	    Object target = null;
  
  	    try {
  
  		    try {
  			field0 = InetAddress.class.getDeclaredField("holder");
  			field0.setAccessible(true);
  			target = field0.get(address);
  			field0 = target.getClass().getDeclaredField("hostName");
  		    } catch( NoSuchFieldException e ) {
  			// Let's try the non-OpenJDK variant
  			field0 = InetAddress.class.getDeclaredField("hostName");
  			target = address;
  		    }                
  
  		    if (field0 != null && target != null && hostName != null) {
  			field0.setAccessible(true);
  			field0.set(target, hostName);
  		    } else {
  			return false;
  		    }
  
  	    } catch (Exception ex) {
                  log.log(Level.SEVERE,
                      "Failed injecting hostName to work around Android InetAddress DNS bug: " + address,
                      ex
                  );
                  return false;
              }
          }
          return result;
      }
  
      @Override
      public InetAddress getLocalAddress(NetworkInterface networkInterface, boolean isIPv6, InetAddress remoteAddress) {
          // TODO: This is totally random because we can't access low level InterfaceAddress on Android!
          for (InetAddress localAddress : getInetAddresses(networkInterface)) {
              if (isIPv6 && localAddress instanceof Inet6Address)
                  return localAddress;
              if (!isIPv6 && localAddress instanceof Inet4Address)
                  return localAddress;
          }
          throw new IllegalStateException("Can't find any IPv4 or IPv6 address on interface: " + networkInterface.getDisplayName());
     }
 
     @Override
     protected void discoverNetworkInterfaces() throws InitializationException {
         try {
             super.discoverNetworkInterfaces();
         } catch (Exception ex) {
             // TODO: ICS bug on some models with network interface disappearing while enumerated
             // http://code.google.com/p/android/issues/detail?id=33661
             log.warning("Exception while enumerating network interfaces, trying once more: " + ex);
             super.discoverNetworkInterfaces();
         }
     }
 }