/**
 * This file Copyright (c) 2008-2012 Magnolia International
 * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
 *
 *
 * This file is dual-licensed under both the Magnolia
 * Network Agreement and the GNU General Public License.
 * You may elect to use one or the other of these licenses.
 *
 * This file is distributed in the hope that it will be
 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
 * Redistribution, except as permitted by whichever of the GPL
 * or MNA you select, is prohibited.
 *
 * 1. For the GPL license (GPL), you can redistribute and/or
 * modify this file under the terms of the GNU General
 * Public License, Version 3, as published by the Free Software
 * Foundation.  You should have received a copy of the GNU
 * General Public License, Version 3 along with this program;
 * if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * 2. For the Magnolia Network Agreement (MNA), this file
 * and the accompanying materials are made available under the
 * terms of the MNA which accompanies this distribution, and
 * is available at http://www.magnolia-cms.com/mna.html
 *
 * Any modifications to this file must keep this entire header
 * intact.
 *
 */
package info.magnolia.cms.util;

import java.util.Enumeration;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Util to work with HTTP headers.
 */
public class RequestHeaderUtil {

    public static boolean acceptsGzipEncoding(HttpServletRequest request) {
        return acceptsEncoding(request, "gzip");
    }

    public static boolean acceptsEncoding(final HttpServletRequest request, final String name) {
        return headerContains(request, "Accept-Encoding", name);
    }

    public static boolean headerContains(final HttpServletRequest request, final String header, final String value) {
        final Enumeration accepted = request.getHeaders(header);
        while (accepted.hasMoreElements()) {
            final String headerValue = (String) accepted.nextElement();
            if (headerValue.indexOf(value) != -1) {
                return true;
            }
        }
        return false;
    }

    public static void addAndVerifyHeader(HttpServletResponse response, String name, String value) {
        response.addHeader(name, value);
        final boolean containsHeader = response.containsHeader(name);
        if (!containsHeader) {
            throw new IllegalStateException("Failure when attempting to set response header " + name + ": " + value);
        }
    }

    public static void setHeader(final HttpServletResponse response, final String name, final Object value) {
        if (value instanceof Long) {
            response.addDateHeader(name, ((Long) value).longValue());
        } else if (value instanceof Integer) {
            response.addIntHeader(name, ((Integer) value).intValue());
        } else if (value instanceof String) {
            response.addHeader(name, (String) value);
        } else {
            throw new IllegalStateException("Unrecognized type for header [" + name + "], value is: " + value);
        }
    }

}