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.net.Authenticator;
import java.net.InetSocketAddress;
import java.net.PasswordAuthentication;
import java.net.SocketAddress;
import java.net.URI;
import java.net.URL;
import java.util.List;
import java.util.Map;
import java.util.UUID;

import org.eclipse.aether.repository.Authentication;
import org.eclipse.aether.repository.AuthenticationContext;
import org.eclipse.aether.repository.AuthenticationDigest;
import org.eclipse.aether.repository.Proxy;
import org.eclipse.aether.repository.ProxySelector;
import org.eclipse.aether.repository.RemoteRepository;

A proxy selector that uses the JRE's global proxy selector. In combination with the system property java.net.useSystemProxies, this proxy selector can be employed to pick up the proxy configuration from the operating system, see Java Networking and Proxies for details. The JRE's global authenticator is used to look up credentials for a proxy when needed. /**
 * A proxy selector that uses the {@link java.net.ProxySelector#getDefault() JRE's global proxy selector}. In
 * combination with the system property {@code java.net.useSystemProxies}, this proxy selector can be employed to pick
 * up the proxy configuration from the operating system, see <a
 * href="http://docs.oracle.com/javase/6/docs/technotes/guides/net/proxies.html">Java Networking and Proxies</a> for
 * details. The {@link java.net.Authenticator JRE's global authenticator} is used to look up credentials for a proxy
 * when needed.
 */
public final class JreProxySelector
    implements ProxySelector
{

    
Creates a new proxy selector that delegates to ProxySelector.getDefault(). /**
     * Creates a new proxy selector that delegates to {@link java.net.ProxySelector#getDefault()}.
     */
    public JreProxySelector()
    {
    }

    public Proxy getProxy( RemoteRepository repository )
    {
        List<java.net.Proxy> proxies = null;
        try
        {
            URI uri = new URI( repository.getUrl() ).parseServerAuthority();
            proxies = java.net.ProxySelector.getDefault().select( uri );
        }
        catch ( Exception e )
        {
            // URL invalid or not accepted by selector or no selector at all, simply use no proxy
        }
        if ( proxies != null )
        {
            for ( java.net.Proxy proxy : proxies )
            {
                if ( java.net.Proxy.Type.DIRECT.equals( proxy.type() ) )
                {
                    break;
                }
                if ( java.net.Proxy.Type.HTTP.equals( proxy.type() ) && isValid( proxy.address() ) )
                {
                    InetSocketAddress addr = (InetSocketAddress) proxy.address();
                    return new Proxy( Proxy.TYPE_HTTP, addr.getHostName(), addr.getPort(),
                                      JreProxyAuthentication.INSTANCE );
                }
            }
        }
        return null;
    }

    private static boolean isValid( SocketAddress address )
    {
        if ( address instanceof InetSocketAddress )
        {
            /*
             * NOTE: On some platforms with java.net.useSystemProxies=true, unconfigured proxies show up as proxy
             * objects with empty host and port 0.
             */
            InetSocketAddress addr = (InetSocketAddress) address;
            if ( addr.getPort() <= 0 )
            {
                return false;
            }
            if ( addr.getHostName() == null || addr.getHostName().length() <= 0 )
            {
                return false;
            }
            return true;
        }
        return false;
    }

    private static final class JreProxyAuthentication
        implements Authentication
    {

        public static final Authentication INSTANCE = new JreProxyAuthentication();

        public void fill( AuthenticationContext context, String key, Map<String, String> data )
        {
            Proxy proxy = context.getProxy();
            if ( proxy == null )
            {
                return;
            }
            if ( !AuthenticationContext.USERNAME.equals( key ) && !AuthenticationContext.PASSWORD.equals( key ) )
            {
                return;
            }

            try
            {
                URL url;
                try
                {
                    url = new URL( context.getRepository().getUrl() );
                }
                catch ( Exception e )
                {
                    url = null;
                }

                PasswordAuthentication auth =
                    Authenticator.requestPasswordAuthentication( proxy.getHost(), null, proxy.getPort(), "http",
                                                                 "Credentials for proxy " + proxy, null, url,
                                                                 Authenticator.RequestorType.PROXY );
                if ( auth != null )
                {
                    context.put( AuthenticationContext.USERNAME, auth.getUserName() );
                    context.put( AuthenticationContext.PASSWORD, auth.getPassword() );
                }
                else
                {
                    context.put( AuthenticationContext.USERNAME, System.getProperty( "http.proxyUser" ) );
                    context.put( AuthenticationContext.PASSWORD, System.getProperty( "http.proxyPassword" ) );
                }
            }
            catch ( SecurityException e )
            {
                // oh well, let's hope the proxy can do without auth
            }
        }

        public void digest( AuthenticationDigest digest )
        {
            // we don't know anything about the JRE's current authenticator, assume the worst (i.e. interactive)
            digest.update( UUID.randomUUID().toString() );
        }

        @Override
        public boolean equals( Object obj )
        {
            return this == obj || ( obj != null && getClass().equals( obj.getClass() ) );
        }

        @Override
        public int hashCode()
        {
            return getClass().hashCode();
        }

    }

}