/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.hc.client5.http.impl.auth;
  
  import java.net.Authenticator;
  import java.net.MalformedURLException;
  import java.net.PasswordAuthentication;
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.net.URL;
  
  import org.apache.hc.client5.http.auth.AuthScope;
  import org.apache.hc.client5.http.auth.Credentials;
  import org.apache.hc.client5.http.auth.CredentialsStore;
  import org.apache.hc.client5.http.auth.NTCredentials;
  import org.apache.hc.client5.http.auth.UsernamePasswordCredentials;
  import org.apache.hc.client5.http.auth.StandardAuthScheme;
  import org.apache.hc.client5.http.protocol.HttpClientContext;
  import org.apache.hc.core5.annotation.Contract;
  import org.apache.hc.core5.annotation.ThreadingBehavior;
  import org.apache.hc.core5.http.HttpRequest;
  import org.apache.hc.core5.http.URIScheme;
  import org.apache.hc.core5.http.protocol.HttpContext;
  import org.apache.hc.core5.util.Args;
  
  /**
   * Implementation of {@link CredentialsStore} backed by standard
   * JRE {@link Authenticator}.
   *
   * @since 4.3
   */
  @Contract(threading = ThreadingBehavior.SAFE)
  public class SystemDefaultCredentialsProvider implements CredentialsStore {
  
      private final BasicCredentialsProvider internal;
  
      /**
       * Default constructor.
       */
      public SystemDefaultCredentialsProvider() {
          super();
          this.internal = new BasicCredentialsProvider();
      }
  
      @Override
      public void setCredentials(final AuthScope authScope, final Credentials credentials) {
          internal.setCredentials(authScope, credentials);
      }
  
      private static PasswordAuthentication getSystemCreds(
              final String protocol,
              final AuthScope authScope,
              final Authenticator.RequestorType requestorType,
              final HttpClientContext context) {
          final HttpRequest request = context != null ? context.getRequest() : null;
          URL targetHostURL;
          try {
              final URI uri = request != null ? request.getUri() : null;
              targetHostURL = uri != null ? uri.toURL() : null;
          } catch (final URISyntaxException | MalformedURLException ignore) {
              targetHostURL = null;
          }
          // use null addr, because the authentication fails if it does not exactly match the expected realm's host
          return Authenticator.requestPasswordAuthentication(
                  authScope.getHost(),
                  null,
                  authScope.getPort(),
                  protocol,
                  authScope.getRealm(),
                  authScope.getSchemeName(),
                  targetHostURL,
                  requestorType);
      }
  
      @Override
     public Credentials getCredentials(final AuthScope authScope, final HttpContext context) {
         Args.notNull(authScope, "Auth scope");
         final Credentials localcreds = internal.getCredentials(authScope, context);
         if (localcreds != null) {
             return localcreds;
         }
         final String host = authScope.getHost();
         if (host != null) {
             final HttpClientContext clientContext = context != null ? HttpClientContext.adapt(context) : null;
             final String protocol = authScope.getProtocol() != null ? authScope.getProtocol() : (authScope.getPort() == 443 ? URIScheme.HTTPS.id : URIScheme.HTTP.id);
             PasswordAuthentication systemcreds = getSystemCreds(
                     protocol, authScope, Authenticator.RequestorType.SERVER, clientContext);
             if (systemcreds == null) {
                 systemcreds = getSystemCreds(
                         protocol, authScope, Authenticator.RequestorType.PROXY, clientContext);
             }
             if (systemcreds == null) {
                 // Look for values given using http.proxyUser/http.proxyPassword or
                 // https.proxyUser/https.proxyPassword. We cannot simply use the protocol from
                 // the origin since a proxy retrieved from https.proxyHost/https.proxyPort will
                 // still use http as protocol
                 systemcreds = getProxyCredentials(URIScheme.HTTP.getId(), authScope);
                 if (systemcreds == null) {
                     systemcreds = getProxyCredentials(URIScheme.HTTPS.getId(), authScope);
                 }
             }
             if (systemcreds != null) {
                 final String domain = System.getProperty("http.auth.ntlm.domain");
                 if (domain != null) {
                     return new NTCredentials(systemcreds.getUserName(), systemcreds.getPassword(), null, domain);
                 }
                 if (StandardAuthScheme.NTLM.equalsIgnoreCase(authScope.getSchemeName())) {
                     // Domain may be specified in a fully qualified user name
                     return new NTCredentials(
                             systemcreds.getUserName(), systemcreds.getPassword(), null, null);
                 }
                 return new UsernamePasswordCredentials(systemcreds.getUserName(), systemcreds.getPassword());
             }
         }
         return null;
     }
 
     private static PasswordAuthentication getProxyCredentials(final String protocol, final AuthScope authScope) {
         final String proxyHost = System.getProperty(protocol + ".proxyHost");
         if (proxyHost == null) {
             return null;
         }
         final String proxyPort = System.getProperty(protocol + ".proxyPort");
         if (proxyPort == null) {
             return null;
         }
 
         try {
             final AuthScope systemScope = new AuthScope(proxyHost, Integer.parseInt(proxyPort));
             if (authScope.match(systemScope) >= 0) {
                 final String proxyUser = System.getProperty(protocol + ".proxyUser");
                 if (proxyUser == null) {
                     return null;
                 }
                 final String proxyPassword = System.getProperty(protocol + ".proxyPassword");
 
                 return new PasswordAuthentication(proxyUser,
                         proxyPassword != null ? proxyPassword.toCharArray() : new char[] {});
             }
         } catch (final NumberFormatException ex) {
         }
 
         return null;
     }
 
     @Override
     public void clear() {
         internal.clear();
     }
 
 }