/*
    * This file is part of dependency-check-core.
    *
    * Licensed 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.
   *
   * Copyright (c) 2014 Jeremy Long. All Rights Reserved.
   */
  package org.owasp.dependencycheck.utils;
  
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import org.apache.commons.lang3.StringUtils;
  
  import java.io.IOException;
  import java.net.Authenticator;
  import java.net.HttpURLConnection;
  import java.net.InetSocketAddress;
  import java.net.PasswordAuthentication;
  import java.net.Proxy;
  import java.net.SocketAddress;
  import java.net.URL;
  
  /**
   * A URLConnection Factory to create new connections. This encapsulates several configuration checks to ensure that the connection
   * uses the correct proxy settings.
   *
   * @author Jeremy Long
   */
  public final class URLConnectionFactory {
  
      /**
       * Private constructor for this factory.
       */
      private URLConnectionFactory() {
      }
  
      /**
       * Utility method to create an HttpURLConnection. If the application is configured to use a proxy this method will retrieve
       * the proxy settings and use them when setting up the connection.
       *
       * @param url the url to connect to
       * @return an HttpURLConnection
       * @throws URLConnectionFailureException thrown if there is an exception
       */
      @SuppressFBWarnings(value = "RCN_REDUNDANT_NULLCHECK_OF_NULL_VALUE", justification = "Just being extra safe")
      public static HttpURLConnection createHttpURLConnection(URL url) throws URLConnectionFailureException {
          HttpURLConnection conn = null;
          final String proxyUrl = Settings.getString(Settings.KEYS.PROXY_SERVER);
  
          try {
              if (proxyUrl != null && !matchNonProxy(url)) {
                  final int proxyPort = Settings.getInt(Settings.KEYS.PROXY_PORT);
                  final SocketAddress address = new InetSocketAddress(proxyUrl, proxyPort);
  
                  final String username = Settings.getString(Settings.KEYS.PROXY_USERNAME);
                  final String password = Settings.getString(Settings.KEYS.PROXY_PASSWORD);
  
                  if (username != null && password != null) {
                      final Authenticator auth = new Authenticator() {
                          @Override
                          public PasswordAuthentication getPasswordAuthentication() {
                              if (getRequestorType().equals(Authenticator.RequestorType.PROXY)) {
                                  return new PasswordAuthentication(username, password.toCharArray());
                              }
                              return super.getPasswordAuthentication();
                          }
                      };
                      Authenticator.setDefault(auth);
                  }
  
                  final Proxy proxy = new Proxy(Proxy.Type.HTTP, address);
                  conn = (HttpURLConnection) url.openConnection(proxy);
              } else {
                  conn = (HttpURLConnection) url.openConnection();
              }
              final int timeout = Settings.getInt(Settings.KEYS.CONNECTION_TIMEOUT, 10000);
              conn.setConnectTimeout(timeout);
              conn.setInstanceFollowRedirects(true);
          } catch (IOException ex) {
              if (conn != null) {
                  try {
                      conn.disconnect();
                  } finally {
                      conn = null;
                  }
              }
              throw new URLConnectionFailureException("Error getting connection.", ex);
          }
          return conn;
      }
 
     /**
      * Check if hostname matches nonProxy settings
      *
      * @param url the url to connect to
      * @return matching result. true: match nonProxy
      */
     private static boolean matchNonProxy(final URL url) {
         final String host = url.getHost();
 
         // code partially from org.apache.maven.plugins.site.AbstractDeployMojo#getProxyInfo
         final String nonProxyHosts = Settings.getString(Settings.KEYS.PROXY_NON_PROXY_HOSTS);
         if (null != nonProxyHosts) {
             final String[] nonProxies = nonProxyHosts.split("(,)|(;)|(\\|)");
             for (final String nonProxyHost : nonProxies) {
                 //if ( StringUtils.contains( nonProxyHost, "*" ) )
                 if (null != nonProxyHost && nonProxyHost.contains("*")) {
                     // Handle wildcard at the end, beginning or middle of the nonProxyHost
                     final int pos = nonProxyHost.indexOf('*');
                     final String nonProxyHostPrefix = nonProxyHost.substring(0, pos);
                     final String nonProxyHostSuffix = nonProxyHost.substring(pos + 1);
                     // prefix*
                     if (!StringUtils.isEmpty(nonProxyHostPrefix) && host.startsWith(nonProxyHostPrefix) && StringUtils.isEmpty(nonProxyHostSuffix)) {
                         return true;
                     }
                     // *suffix
                     if (StringUtils.isEmpty(nonProxyHostPrefix) && !StringUtils.isEmpty(nonProxyHostSuffix) && host.endsWith(nonProxyHostSuffix)) {
                         return true;
                     }
                     // prefix*suffix
                     if (!StringUtils.isEmpty(nonProxyHostPrefix) && host.startsWith(nonProxyHostPrefix) && !StringUtils.isEmpty(nonProxyHostSuffix)
                             && host.endsWith(nonProxyHostSuffix)) {
                         return true;
                     }
                 } else if (host.equals(nonProxyHost)) {
                     return true;
                 }
             }
         }
         return false;
     }
 
     /**
      * Utility method to create an HttpURLConnection. The use of a proxy here is optional as there may be cases where a proxy is
      * configured but we don't want to use it (for example, if there's an internal repository configured)
      *
      * @param url the URL to connect to
      * @param proxy whether to use the proxy (if configured)
      * @return a newly constructed HttpURLConnection
      * @throws URLConnectionFailureException thrown if there is an exception
      */
     public static HttpURLConnection createHttpURLConnection(URL url, boolean proxy) throws URLConnectionFailureException {
         if (proxy) {
             return createHttpURLConnection(url);
         }
         HttpURLConnection conn = null;
         try {
             conn = (HttpURLConnection) url.openConnection();
             final int timeout = Settings.getInt(Settings.KEYS.CONNECTION_TIMEOUT, 10000);
             conn.setConnectTimeout(timeout);
             conn.setInstanceFollowRedirects(true);
         } catch (IOException ioe) {
             throw new URLConnectionFailureException("Error getting connection.", ioe);
         }
         return conn;
     }
 }