//
//  ========================================================================
//  Copyright (c) 1995-2018 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.websocket.server;

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

import org.eclipse.jetty.websocket.api.extensions.ExtensionConfig;
import org.eclipse.jetty.websocket.common.AcceptHash;
import org.eclipse.jetty.websocket.servlet.ServletUpgradeRequest;
import org.eclipse.jetty.websocket.servlet.ServletUpgradeResponse;

/**
 * WebSocket Handshake for <a href="https://tools.ietf.org/html/rfc6455">RFC 6455</a>.
 */
public class HandshakeRFC6455 implements WebSocketHandshake
{
    /** RFC 6455 - Sec-WebSocket-Version */
    public static final int VERSION = 13;

    @Override
    public void doHandshakeResponse(ServletUpgradeRequest request, ServletUpgradeResponse response) throws IOException
    {
        String key = request.getHeader("Sec-WebSocket-Key");

        if (key == null)
        {
            throw new IllegalStateException("Missing request header 'Sec-WebSocket-Key'");
        }

        // build response
        response.setHeader("Upgrade","WebSocket");
        response.addHeader("Connection","Upgrade");
        response.addHeader("Sec-WebSocket-Accept",AcceptHash.hashKey(key));

        if (response.getExtensions() != null)
        {
            String value = ExtensionConfig.toHeaderValue(response.getExtensions());
            if (value != null)
            {
                response.addHeader("Sec-WebSocket-Extensions",value);
            }
        }

        request.complete();

        response.setStatus(HttpServletResponse.SC_SWITCHING_PROTOCOLS);
        response.complete();
    }
}
