/*
    * DavMail POP/IMAP/SMTP/CalDav/LDAP Exchange Gateway
    * Copyright (C) 2010  Mickael Guessant
    *
    * This program is free software; you can redistribute it and/or
    * modify it under the terms of the GNU General Public License
    * as published by the Free Software Foundation; either version 2
    * of the License, or (at your option) any later version.
    *
   * 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.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
   */
  
  package davmail.http;
  
  import davmail.Settings;
  import org.apache.log4j.Logger;
  
  import java.io.IOException;
  import java.net.InetSocketAddress;
  import java.net.Proxy;
  import java.net.ProxySelector;
  import java.net.SocketAddress;
  import java.net.URI;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  /**
   * Custom proxy selector based on DavMail settings.
   * Interactive O365 authentication relies on native HttpUrlConnection so we need to override default proxy selector.
   */
  public class DavGatewayProxySelector extends ProxySelector {
      static final Logger LOGGER = Logger.getLogger(DavGatewayProxySelector.class);
  
      static final List<Proxy> DIRECT = Collections.singletonList(Proxy.NO_PROXY);
  
      ProxySelector proxySelector;
  
      public DavGatewayProxySelector(ProxySelector proxySelector) {
          this.proxySelector = proxySelector;
      }
  
      @Override
      public List<Proxy> select(URI uri) {
          boolean useSystemProxies = Settings.getBooleanProperty("davmail.useSystemProxies", Boolean.FALSE);
          boolean enableProxy = Settings.getBooleanProperty("davmail.enableProxy");
          String proxyHost = Settings.getProperty("davmail.proxyHost");
          int proxyPort = Settings.getIntProperty("davmail.proxyPort");
          String scheme = uri.getScheme();
          if ("socket".equals(scheme)) {
              return DIRECT;
          } else if (useSystemProxies) {
              List<Proxy> proxyes = proxySelector.select(uri);
              LOGGER.debug("Selected " + proxyes + " proxy for " + uri);
              return proxyes;
          } else if (enableProxy
                  && proxyHost != null && proxyHost.length() > 0 && proxyPort > 0
                  && !isNoProxyFor(uri)
                  && ("http".equals(scheme) || "https".equals(scheme))) {
              // DavMail defined proxies
              ArrayList<Proxy> proxies = new ArrayList<>();
              proxies.add(new Proxy(Proxy.Type.HTTP, InetSocketAddress.createUnresolved(proxyHost, proxyPort)));
              return proxies;
          } else {
              return DIRECT;
          }
      }
  
      private boolean isNoProxyFor(URI uri) {
          final String noProxyFor = Settings.getProperty("davmail.noProxyFor");
          if (noProxyFor != null) {
              final String urihost = uri.getHost().toLowerCase();
              final String[] domains = noProxyFor.toLowerCase().split(",\\s*");
              for (String domain : domains) {
                  if (urihost.endsWith(domain)) {
                      return true; //break;
                  }
              }
          }
          return false;
      }
  
      @Override
      public void connectFailed(URI uri, SocketAddress sa, IOException ioe) {
          LOGGER.debug("Connection to " + uri + " failed, socket address " + sa + " " + ioe);
          proxySelector.connectFailed(uri, sa, ioe);
      }
  }