/*
    * 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.
   */
  package org.apache.maven.plugins.site.deploy;
  
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import java.io.File;
  import java.io.IOException;
  import java.nio.file.Files;
  import java.util.ArrayList;
  import java.util.Base64;
  import java.util.Enumeration;
  import java.util.List;
  import java.util.Map;
  
  import org.eclipse.jetty.proxy.AsyncProxyServlet;
  
  /**
   * @author Olivier Lamy
   */
  public class AuthAsyncProxyServlet extends AsyncProxyServlet {
      private Map<String, String> authentications;
  
      private long sleepTime = 0;
  
      List<HttpRequest> httpRequests = new ArrayList<>();
  
      private File siteTargetPath;
  
      /**
       * Constructor for non authentication servlet.
       */
      public AuthAsyncProxyServlet(File siteTargetPath) {
          super();
          this.siteTargetPath = siteTargetPath;
      }
  
      /**
       * Constructor for authentication servlet.
       *
       * @param authentications a map of user/password
       */
      public AuthAsyncProxyServlet(Map<String, String> authentications, File siteTargetPath) {
          this(siteTargetPath);
  
          this.authentications = authentications;
      }
  
      /**
       * Constructor for authentication servlet.
       *
       * @param authentications a map of user/password
       * @param sleepTime a positive time to sleep the service thread (for timeout)
       */
      public AuthAsyncProxyServlet(Map<String, String> authentications, long sleepTime, File siteTargetPath) {
          this(siteTargetPath);
  
          this.authentications = authentications;
          this.sleepTime = sleepTime;
      }
  
      /** {@inheritDoc} */
      @Override
      public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
          final HttpServletRequest request = (HttpServletRequest) req;
          final HttpServletResponse response = (HttpServletResponse) res;
  
          if (this.authentications != null && !this.authentications.isEmpty()) {
              String proxyAuthorization = request.getHeader("Proxy-Authorization");
              if (proxyAuthorization != null && proxyAuthorization.startsWith("Basic ")) {
                  String proxyAuth = proxyAuthorization.substring(6);
                  String authorization = new String(Base64.getDecoder().decode(proxyAuth));
                  String[] authTokens = authorization.split(":");
                  String user = authTokens[0];
                  String password = authTokens[1];
  
                  if (this.authentications.get(user) == null) {
                      throw new IllegalArgumentException(user + " not found in the map!");
                  }
 
                 if (sleepTime > 0) {
                     try {
                         Thread.sleep(sleepTime);
                     } catch (InterruptedException e) {
                         // nop
                     }
                 }
                 String authPass = this.authentications.get(user);
                 if (password.equals(authPass)) {
                     String targetPath = request.getServletPath();
 
                     HttpRequest rq = new HttpRequest();
                     rq.method = request.getMethod();
                     rq.path = targetPath;
 
                     @SuppressWarnings("rawtypes")
                     Enumeration headerNames = request.getHeaderNames();
                     while (headerNames.hasMoreElements()) {
                         String name = (String) headerNames.nextElement();
                         rq.headers.put(name, request.getHeader(name));
                     }
 
                     httpRequests.add(rq);
 
                     if (request.getMethod().equalsIgnoreCase("PUT") && targetPath != null) {
                         File targetFile = new File(siteTargetPath, targetPath);
                         targetFile.getParentFile().mkdirs();
                         Files.copy(request.getInputStream(), targetFile.toPath());
                     }
 
                     response.setStatus(HttpServletResponse.SC_OK);
                     return;
                 }
             }
 
             // Proxy-Authenticate Basic realm="CCProxy Authorization"
             response.addHeader("Proxy-Authenticate", "Basic realm=\"Jetty Proxy Authorization\"");
             response.setStatus(HttpServletResponse.SC_PROXY_AUTHENTICATION_REQUIRED);
             return;
         }
 
         super.service(req, res);
     }
 }