/*
 * LinShare is an open source filesharing software, part of the LinPKI software
 * suite, developed by Linagora.
 * 
 * Copyright (C) 2013 LINAGORA
 * 
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option) any
 * later version, provided you comply with the Additional Terms applicable for
 * LinShare software by Linagora pursuant to Section 7 of the GNU Affero General
 * Public License, subsections (b), (c), and (e), pursuant to which you must
 * notably (i) retain the display of the “LinShare™” trademark/logo at the top
 * of the interface window, the display of the “You are using the Open Source
 * and free version of LinShare™, powered by Linagora © 2009–2013. Contribute to
 * Linshare R&D by subscribing to an Enterprise offer!” infobox and in the
 * e-mails sent with the Program, (ii) retain all hypertext links between
 * LinShare and linshare.org, between linagora.com and Linagora, and (iii)
 * refrain from infringing Linagora intellectual property rights over its
 * trademarks and commercial brands. Other Additional Terms apply, see
 * <http://www.linagora.com/licenses/> for more details.
 * 
 * This program 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 Affero General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Affero General Public License and
 * its applicable Additional Terms for LinShare along with this program. If not,
 * see <http://www.gnu.org/licenses/> for the GNU Affero General Public License
 * version 3 and <http://www.linagora.com/licenses/> for the Additional Terms
 * applicable to LinShare software.
 */
package org.linagora.linshare.auth;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.web.authentication.preauth.RequestHeaderAuthenticationFilter;
import org.springframework.util.Assert;

/**
 * This Spring Security filter is designed to filter authentication
 * against a LemonLDAP::NG Web Single Sign On
 * @author Clement Oudot &lt;coudot@linagora.com&gt;
 */
public class PreAuthenticationHeader extends RequestHeaderAuthenticationFilter {

	/** */
	private String principalRequestHeader;
	
	/** List of IP / DNS hostname */
	private List<String> authorizedAddresses;
	
	private static Logger logger = LoggerFactory.getLogger(PreAuthenticationHeader.class);

	public PreAuthenticationHeader(String authorizedAddressesList) {
		super();
		if( authorizedAddressesList!=null ) {
			@SuppressWarnings("unchecked")
			List<String> asList = Arrays.asList(authorizedAddressesList.split(","));
			this.authorizedAddresses = asList;		
		} else {
			this.authorizedAddresses = new ArrayList<String>();
		}
	}

	@Override
	protected Object getPreAuthenticatedPrincipal(HttpServletRequest request) {
		// Do not throw exception if header is not set
		String authenticationHeader = request.getHeader(principalRequestHeader);
		if(authenticationHeader != null) {
			if(!authorizedAddresses.contains(request.getRemoteAddr())) {
				logger.error("SECURITY ALERT: Unauthorized header value '" + authenticationHeader 
						+ "' from IP: " + request.getRemoteAddr() + ":" + request.getRemotePort());
				return null;
			}
		}
		return authenticationHeader;
	}

	public void setPrincipalRequestHeader(String principalRequestHeader) {
		Assert.hasText(principalRequestHeader, "principalRequestHeader must not be empty or null");
		this.principalRequestHeader = principalRequestHeader;
	}

	public void setAuthorizedAddresses(List<String> authorizedAddresses) {
		Assert.hasText(authorizedAddresses.toString(), "authorizedAddresses must not be empty or null");
		this.authorizedAddresses = authorizedAddresses;
	}
}
