package org.eclipse.aether.util.repository;
   
   /*
    * 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.
   */
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import static java.util.Objects.requireNonNull;
  import java.util.StringTokenizer;
  import java.util.regex.Pattern;
  
  import org.eclipse.aether.repository.Proxy;
  import org.eclipse.aether.repository.ProxySelector;
  import org.eclipse.aether.repository.RemoteRepository;
  
  /**
   * A simple proxy selector that selects the first matching proxy from a list of configured proxies.
   */
  public final class DefaultProxySelector
      implements ProxySelector
  {
  
      private final List<ProxyDef> proxies = new ArrayList<>();
  
      /**
       * Adds the specified proxy definition to the selector. Proxy definitions are ordered, the first matching proxy for
       * a given repository will be used.
       * 
       * @param proxy The proxy definition to add, must not be {@code null}.
       * @param nonProxyHosts The list of (case-insensitive) host names to exclude from proxying, may be {@code null}.
       * @return This proxy selector for chaining, never {@code null}.
       */
      public DefaultProxySelector add( Proxy proxy, String nonProxyHosts )
      {
          requireNonNull( proxy, "proxy cannot be null" );
          proxies.add( new ProxyDef( proxy, nonProxyHosts ) );
  
          return this;
      }
  
      public Proxy getProxy( RemoteRepository repository )
      {
          requireNonNull( repository, "repository cannot be null" );
          Map<String, ProxyDef> candidates = new HashMap<>();
  
          String host = repository.getHost();
          for ( ProxyDef proxy : proxies )
          {
              if ( !proxy.nonProxyHosts.isNonProxyHost( host ) )
              {
                  String key = proxy.proxy.getType().toLowerCase( Locale.ENGLISH );
                  if ( !candidates.containsKey( key ) )
                  {
                      candidates.put( key, proxy );
                  }
              }
          }
  
          String protocol = repository.getProtocol().toLowerCase( Locale.ENGLISH );
  
          if ( "davs".equals( protocol ) )
          {
              protocol = "https";
          }
          else if ( "dav".equals( protocol ) )
          {
              protocol = "http";
          }
          else if ( protocol.startsWith( "dav:" ) )
          {
              protocol = protocol.substring( "dav:".length() );
          }
  
          ProxyDef proxy = candidates.get( protocol );
          if ( proxy == null && "https".equals( protocol ) )
          {
              proxy = candidates.get( "http" );
          }
  
          return ( proxy != null ) ? proxy.proxy : null;
     }
 
     static class NonProxyHosts
     {
 
         private final Pattern[] patterns;
 
         NonProxyHosts( String nonProxyHosts )
         {
             List<Pattern> patterns = new ArrayList<>();
             if ( nonProxyHosts != null )
             {
                 for ( StringTokenizer tokenizer = new StringTokenizer( nonProxyHosts, "|" );
                       tokenizer.hasMoreTokens(); )
                 {
                     String pattern = tokenizer.nextToken();
                     pattern = pattern.replace( ".", "\\." ).replace( "*", ".*" );
                     patterns.add( Pattern.compile( pattern, Pattern.CASE_INSENSITIVE ) );
                 }
             }
             this.patterns = patterns.toArray( new Pattern[patterns.size()] );
         }
 
         boolean isNonProxyHost( String host )
         {
             if ( host != null )
             {
                 for ( Pattern pattern : patterns )
                 {
                     if ( pattern.matcher( host ).matches() )
                     {
                         return true;
                     }
                 }
             }
             return false;
         }
 
     }
 
     static class ProxyDef
     {
 
         final Proxy proxy;
 
         final NonProxyHosts nonProxyHosts;
 
         ProxyDef( Proxy proxy, String nonProxyHosts )
         {
             this.proxy = proxy;
             this.nonProxyHosts = new NonProxyHosts( nonProxyHosts );
         }
 
     }
 
 }