/**
 *  ProxySettings
 *  Copyright 2010 by Michael Peter Christen
 *  First released 25.05.2010 at http://yacy.net
 *
 *  $LastChangedDate$
 *  $LastChangedRevision$
 *  $LastChangedBy$
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *  
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program in the file lgpl21.txt
 *  If not, see <http://www.gnu.org/licenses/>.
 */

package net.yacy.cora.protocol.http;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.http.HttpException;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.Credentials;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.conn.routing.HttpRoute;
import org.apache.http.conn.routing.HttpRoutePlanner;
import org.apache.http.protocol.HttpContext;

/**
 * settings for a remote proxy
 *
 */
public final class ProxySettings {

    // Dummy value to associate with an Object in the backing Map
    private static final Object PRESENT = new Object();
    
    public static enum Protocol {
        HTTP, HTTPS
    }
    
    private static       boolean     use = false, use4ssl = false;
    public static       String      host = null, user = "", password = "";
    public static       int         port = 0;
    public static       String[]    noProxy  = null;
    public static final Map<String, Object> allowProxy    = new ConcurrentHashMap<String, Object>();
    public static final Map<String, Object> disallowProxy = new ConcurrentHashMap<String, Object>();

    public static void setProxyUse4HTTP(boolean use4http0) {
        use = use4http0;
    }
    public static void setProxyUse4HTTPS(boolean use4https0) {
        use4ssl = use4https0;
    }
    
    /**
     * 
     * @return the HttpHost to be used as proxy
     */
    public static HttpHost getProxyHost() {
    	if (!use) return null;
    	return new HttpHost(host, port);
    }
    
    public static HttpRoutePlanner RoutePlanner = new HttpRoutePlanner() {

		@Override
		public HttpRoute determineRoute(HttpHost target, HttpRequest request, HttpContext context) throws HttpException {
			if (use) {
				final Protocol protocol = "https".equalsIgnoreCase(target.getSchemeName())? Protocol.HTTPS : Protocol.HTTP;
				if (useForHost(target.getHostName(), protocol))
					return new HttpRoute(target, null,  getProxyHost(), protocol == Protocol.HTTPS);
			}
			return new HttpRoute(target); // direct
		}
    };
    
    public static CredentialsProvider CredsProvider = new CredentialsProvider() {

		@Override
		public void clear() {
		}

		@Override
		public Credentials getCredentials(AuthScope scope) {
			if (host != null && host.equals(scope.getHost()) && port == scope.getPort())
				return new UsernamePasswordCredentials(user, password);
			return null;
		}

		@Override
		public void setCredentials(AuthScope arg0, Credentials arg1) {
		}
    };
    
    /**
     * tell if a remote proxy will be used for the given host
     * @param host
     * @return true, if the proxy shall be used for the given host
     */
    public static boolean useForHost(final String host, Protocol protocol) {
        assert protocol != null;
        if (!use) return false;
        if (protocol == Protocol.HTTPS && !use4ssl) return false;
        if (allowProxy.containsKey(host)) return true;
        if (disallowProxy.containsKey(host)) return false;
        for (String pattern: noProxy) {
            if (host.matches(pattern)) {
                disallowProxy.put(host, PRESENT);
                return false;
            }
        }
        allowProxy.put(host, PRESENT);
        return true;
    }

}