/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-06 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 library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *  $Id$
 */
package org.exist.http.webdav.methods;

import org.exist.EXistException;
import org.exist.collections.Collection;
import org.exist.dom.DocumentImpl;
import org.exist.dom.DocumentMetadata;
import org.exist.security.Permission;
import org.exist.security.PermissionDeniedException;
import org.exist.security.User;
import org.exist.storage.BrokerPool;
import org.exist.storage.DBBroker;
import org.exist.storage.lock.Lock;
import org.exist.xmldb.XmldbURI;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * @author wolf
 */
public class Head extends AbstractWebDAVMethod {
	
	public Head(BrokerPool pool) {
		super(pool);
	}
	
	/* (non-Javadoc)
	 * @see org.exist.http.webdav.WebDAVMethod#process(org.exist.security.User, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, org.exist.collections.Collection, org.exist.dom.DocumentImpl)
	 */
	public void process(User user, HttpServletRequest request,
			HttpServletResponse response, XmldbURI path) throws ServletException, IOException {
		DBBroker broker = null;
		Collection collection = null;
		DocumentImpl resource = null;
		try {
			broker = pool.get(user);
			collection = broker.openCollection(path, Lock.READ_LOCK);
			if(collection != null) {
                response.setContentLength(0);
                response.addDateHeader("Last-Modified", collection.getCreationTime());
                response.addDateHeader("Created", collection.getCreationTime());
				return;
			}
			//TODO : release collection lock here ?
			
			resource = broker.getXMLResource(path, Lock.READ_LOCK);
			if(resource == null) {
				response.sendError(HttpServletResponse.SC_NOT_FOUND, "Resource not found");
				return;
			}
			if(!resource.getPermissions().validate(user, Permission.READ)) {
				response.sendError(HttpServletResponse.SC_FORBIDDEN, READ_PERMISSION_DENIED);
				return;
			}
			DocumentMetadata metadata = resource.getMetadata();
			response.setContentType(metadata.getMimeType());
			response.setContentLength(resource.getContentLength());
			response.addDateHeader("Last-Modified", metadata.getLastModified());
			response.addDateHeader("Created", metadata.getCreated());
		} catch (EXistException e) {
			throw new ServletException(e.getMessage(), e);
		} catch (PermissionDeniedException e) {
			response.sendError(HttpServletResponse.SC_FORBIDDEN, READ_PERMISSION_DENIED);
		} finally {
            pool.release(broker);
            if(collection != null)
				collection.release(Lock.READ_LOCK);
			if(resource != null)
				resource.getUpdateLock().release(Lock.READ_LOCK);
		}
	}
}