/***************************************************************
 *  This file is part of the [fleXive](R) framework.
 *
 *  Copyright (c) 1999-2010
 *  UCS - unique computing solutions gmbh (http://www.ucs.at)
 *  All rights reserved
 *
 *  The [fleXive](R) project is free software; you can redistribute
 *  it and/or modify it under the terms of the GNU Lesser General Public
 *  License version 2.1 or higher as published by the Free Software Foundation.
 *
 *  The GNU Lesser General Public License can be found at
 *  http://www.gnu.org/licenses/lgpl.html.
 *  A copy is found in the textfile LGPL.txt and important notices to the
 *  license from the author are found in LICENSE.txt distributed with
 *  these libraries.
 *
 *  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 General Public License for more details.
 *
 *  For further information about UCS - unique computing solutions gmbh,
 *  please see the company website: http://www.ucs.at
 *
 *  For further information about [fleXive](R), please see the
 *  project website: http://www.flexive.org
 *
 *
 *  This copyright notice MUST APPEAR in all copies of the file!
 ***************************************************************/
package com.flexive.cms.war;

import com.flexive.cms.war.facelets.CmsResourceResolver;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;

/**
 * CMS request-related utilities. The methods in this class should not assume
 * a JSF context, since they may be called from Servlets and Filters that do
 * not have a JSF context.
 * 
 * @author Daniel Lichtenberger (daniel.lichtenberger@flexive.com), UCS - unique computing solutions gmbh (http://www.ucs.at)
 * @version $Rev: 55 $
 */
public class CmsRequestUtils {
    private static final String REQ_FLAGS = "CRU_RequestFlags";

    private CmsRequestUtils() {
    }

    /**
     * @param request   the request
     * @return          true if the request explicitly requires edit templates (__edit)
     */
    public static boolean isEditTemplatesRequest(ServletRequest request) {
        return isMatchingRequest(request, true, false);
    }

    /**
     * @param request   the request
     * @return          true if the request explicitly requests live templates (__live)
     */
    public static boolean isLiveTemplatesRequest(ServletRequest request) {
        return isMatchingRequest(request, false, true);
    }

    /**
     * @param request   the request
     * @return          true if the request covers a normal website page,
     *                  and not a CMS frontend page (__edit or __live
     *                  path prefix)
     */
    public static boolean isWebsiteRequest(ServletRequest request) {
        return !isMatchingRequest(request, true, true);
    }

    /**
     * @param request   the request
     * @return          the requested URI, without the context path
     */
    public static String getRequestedURI(ServletRequest request) {
        if (request instanceof HttpServletRequest) {
            // strip path - don't cache result in request because
            // we cannot detect forwards reliably
            final HttpServletRequest httpRequest = (HttpServletRequest) request;
            return httpRequest.getRequestURI().substring(
                    httpRequest.getContextPath().length()
            );
        }
        return null;
    }

    /**
     * Return true if the request matches the given conditions.
     *
     * @param request       the request
     * @param editTemplates if true, then edit mode urls (__edit/*) will be matched
     * @param liveTemplates if true, then live template urls (__live/*) will be matched
     */
    private static boolean isMatchingRequest(ServletRequest request, boolean editTemplates, boolean liveTemplates) {
        final RequestFlags flags = getRequestFlags(request);
        return editTemplates && flags.isEditTemplates()
                || liveTemplates && flags.isLiveTemplates();
    }

    private static RequestFlags getRequestFlags(ServletRequest request) {
        if (request.getAttribute(REQ_FLAGS) == null) {
            if (request instanceof HttpServletRequest) {
                final String uri = getRequestedURI(request);
                request.setAttribute(REQ_FLAGS, new RequestFlags(
                        uri.startsWith(CmsResourceResolver.EDIT_PATH),
                        uri.startsWith(CmsResourceResolver.LIVE_PATH)
                ));
            } else {
                // set null object
                request.setAttribute(REQ_FLAGS, NON_HTTP_FLAGS);
            }
        }
        return (RequestFlags) request.getAttribute(REQ_FLAGS);
    }



    /**
     * Cache CMS-related flags extracted from the request URI.
     */
    private static class RequestFlags {
        private final boolean editTemplates;
        private final boolean liveTemplates;

        public RequestFlags(boolean editTemplates, boolean liveTemplates) {
            this.editTemplates = editTemplates;
            this.liveTemplates = liveTemplates;
        }

        public boolean isEditTemplates() {
            return editTemplates;
        }

        public boolean isLiveTemplates() {
            return liveTemplates;
        }
    }

    private static final RequestFlags NON_HTTP_FLAGS = new RequestFlags(false, false);
}