/*
 * eXist Open Source Native XML Database
 * Copyright (C) 2004-2009 The eXist Project
 * http://exist-db.org
 *
 * This program 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
 * of the License, or (at your option) any later version.
 *  
 * 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 Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *  
 *  $Id$
 */
package org.exist.xquery.functions.xmldb;

import org.apache.log4j.Logger;

import java.net.URISyntaxException;

import org.exist.dom.QName;
import org.exist.security.User;
import org.exist.xmldb.LocalCollection;
import org.exist.xmldb.UserManagementService;
import org.exist.xmldb.XmldbURI;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceIterator;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
import org.xmldb.api.base.Collection;
import org.xmldb.api.base.XMLDBException;

/**
 * @author wolf
 */
public class XMLDBChangeUser extends BasicFunction {
    private static final Logger logger = Logger.getLogger(XMLDBChangeUser.class);

    public final static FunctionSignature signature = new FunctionSignature(
			    new QName("change-user", XMLDBModule.NAMESPACE_URI,
					      XMLDBModule.PREFIX),
			    "Change properties of an existing database user. " +
                XMLDBModule.NEED_PRIV_USER +
                " $user-id is the username, $password is the password, " +
			    "$groups is the sequence of group memberships, " +
                "$home-collection is the home collection. The username, " +
                "$user-id, is mandatory. " +
                "Non-empty values for the other parameters are optional, " +
                "where if empty the existing value is used.",
                new SequenceType[]{
                    new FunctionParameterSequenceType("user-id", Type.STRING, Cardinality.EXACTLY_ONE, "The user-id"),
                    new FunctionParameterSequenceType("password", Type.STRING, Cardinality.ZERO_OR_ONE, "The password"),
                    new FunctionParameterSequenceType("groups", Type.STRING, Cardinality.ZERO_OR_MORE, "The groups the user is member of"),
                    new FunctionParameterSequenceType("home-collection", Type.STRING, Cardinality.ZERO_OR_ONE, "The user's home collection")
                },
                new SequenceType(Type.ITEM, Cardinality.EMPTY));
	
    public XMLDBChangeUser(XQueryContext context) {
	super(context, signature);
    }
	
    /* (non-Javadoc)
     * @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[], org.exist.xquery.value.Sequence)
     */
    public Sequence eval(Sequence[] args, Sequence contextSequence) 
	throws XPathException {

	String userName = args[0].getStringValue();
	Collection collection = null;
		
	try {
	    collection = new LocalCollection(context.getUser(), context.getBroker().getBrokerPool(), XmldbURI.ROOT_COLLECTION_URI, context.getAccessContext());
	    UserManagementService ums = (UserManagementService) collection.getService("UserManagementService", "1.0");
	    User oldUser = ums.getUser(userName);
	    User user = new User(oldUser.getName());
	    if (user == null) {
            logger.error("User " + userName + " not found");
            throw new XPathException(this, "User " + userName + " not found");
	    }
	    if (!args[1].isEmpty()) {
            // set password
            user.setPassword(args[1].getStringValue());
	    } else {
            //use the old password
            user.setEncodedPassword(oldUser.getPassword());
            user.setPasswordDigest(oldUser.getDigestPassword());
	    }
	    if (!args[2].isEmpty()) {
            // set groups
            for(SequenceIterator i = args[2].iterate(); i.hasNext(); ) {
                user.addGroup(i.nextItem().getStringValue());
            }
	    } else
            user.setGroups(oldUser.getGroups());
	    if (!args[3].isEmpty()) {
		// set home collection
		try {
		    user.setHome(XmldbURI.xmldbUriFor(args[3].getStringValue()));
		} catch (URISyntaxException e) {
		    logger.error("Invalid home collection URI " + args[3].getStringValue(), e);
            throw new XPathException(this,"Invalid home collection URI",e);
		}
	    } else
            user.setHome(oldUser.getHome());

	    ums.updateUser(user);
	} catch (XMLDBException xe) {
	    logger.error("Failed to update user " + userName, xe);
	    throw new XPathException(this, "Failed to update user " + userName, xe);
        } finally {
            if (null != collection)
                try { collection.close(); } catch (XMLDBException e) { /* ignore */ }
	}
	
        return Sequence.EMPTY_SEQUENCE;
    }
}