//
//  ========================================================================
//  Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
//  ------------------------------------------------------------------------
//  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.http;

import java.nio.ByteBuffer;

import org.eclipse.jetty.util.ArrayTrie;
import org.eclipse.jetty.util.StringUtil;
import org.eclipse.jetty.util.Trie;

public enum HttpHeader
{

    /**
     * General Fields.
     */
    CONNECTION("Connection"),
    CACHE_CONTROL("Cache-Control"),
    DATE("Date"),
    PRAGMA("Pragma"),
    PROXY_CONNECTION("Proxy-Connection"),
    TRAILER("Trailer"),
    TRANSFER_ENCODING("Transfer-Encoding"),
    UPGRADE("Upgrade"),
    VIA("Via"),
    WARNING("Warning"),
    NEGOTIATE("Negotiate"),

    /**
     * Entity Fields.
     */
    ALLOW("Allow"),
    CONTENT_ENCODING("Content-Encoding"),
    CONTENT_LANGUAGE("Content-Language"),
    CONTENT_LENGTH("Content-Length"),
    CONTENT_LOCATION("Content-Location"),
    CONTENT_MD5("Content-MD5"),
    CONTENT_RANGE("Content-Range"),
    CONTENT_TYPE("Content-Type"),
    EXPIRES("Expires"),
    LAST_MODIFIED("Last-Modified"),

    /**
     * Request Fields.
     */
    ACCEPT("Accept"),
    ACCEPT_CHARSET("Accept-Charset"),
    ACCEPT_ENCODING("Accept-Encoding"),
    ACCEPT_LANGUAGE("Accept-Language"),
    AUTHORIZATION("Authorization"),
    EXPECT("Expect"),
    FORWARDED("Forwarded"),
    FROM("From"),
    HOST("Host"),
    IF_MATCH("If-Match"),
    IF_MODIFIED_SINCE("If-Modified-Since"),
    IF_NONE_MATCH("If-None-Match"),
    IF_RANGE("If-Range"),
    IF_UNMODIFIED_SINCE("If-Unmodified-Since"),
    KEEP_ALIVE("Keep-Alive"),
    MAX_FORWARDS("Max-Forwards"),
    PROXY_AUTHORIZATION("Proxy-Authorization"),
    RANGE("Range"),
    REQUEST_RANGE("Request-Range"),
    REFERER("Referer"),
    TE("TE"),
    USER_AGENT("User-Agent"),
    X_FORWARDED_FOR("X-Forwarded-For"),
    X_FORWARDED_PORT("X-Forwarded-Port"),
    X_FORWARDED_PROTO("X-Forwarded-Proto"),
    X_FORWARDED_SERVER("X-Forwarded-Server"),
    X_FORWARDED_HOST("X-Forwarded-Host"),

    /**
     * Response Fields.
     */
    ACCEPT_RANGES("Accept-Ranges"),
    AGE("Age"),
    ETAG("ETag"),
    LOCATION("Location"),
    PROXY_AUTHENTICATE("Proxy-Authenticate"),
    RETRY_AFTER("Retry-After"),
    SERVER("Server"),
    SERVLET_ENGINE("Servlet-Engine"),
    VARY("Vary"),
    WWW_AUTHENTICATE("WWW-Authenticate"),

    /**
     * WebSocket Fields.
     */
    ORIGIN("Origin"),
    SEC_WEBSOCKET_KEY("Sec-WebSocket-Key"),
    SEC_WEBSOCKET_VERSION("Sec-WebSocket-Version"),
    SEC_WEBSOCKET_EXTENSIONS("Sec-WebSocket-Extensions"),
    SEC_WEBSOCKET_SUBPROTOCOL("Sec-WebSocket-Protocol"),
    SEC_WEBSOCKET_ACCEPT("Sec-WebSocket-Accept"),

    /**
     * Other Fields.
     */
    COOKIE("Cookie"),
    SET_COOKIE("Set-Cookie"),
    SET_COOKIE2("Set-Cookie2"),
    MIME_VERSION("MIME-Version"),
    IDENTITY("identity"),

    X_POWERED_BY("X-Powered-By"),
    HTTP2_SETTINGS("HTTP2-Settings"),

    STRICT_TRANSPORT_SECURITY("Strict-Transport-Security"),

    /**
     * HTTP2 Fields.
     */
    C_METHOD(":method"),
    C_SCHEME(":scheme"),
    C_AUTHORITY(":authority"),
    C_PATH(":path"),
    C_STATUS(":status"),

    UNKNOWN("::UNKNOWN::");

    public static final Trie<HttpHeader> CACHE = new ArrayTrie<>(630);

    static
    {
        for (HttpHeader header : HttpHeader.values())
        {
            if (header != UNKNOWN)
                if (!CACHE.put(header.toString(), header))
                    throw new IllegalStateException();
        }
    }

    private final String _string;
    private final String _lowerCase;
    private final byte[] _bytes;
    private final byte[] _bytesColonSpace;
    private final ByteBuffer _buffer;

    HttpHeader(String s)
    {
        _string = s;
        _lowerCase = StringUtil.asciiToLowerCase(s);
        _bytes = StringUtil.getBytes(s);
        _bytesColonSpace = StringUtil.getBytes(s + ": ");
        _buffer = ByteBuffer.wrap(_bytes);
    }

    public String lowerCaseName()
    {
        return _lowerCase;
    }

    public ByteBuffer toBuffer()
    {
        return _buffer.asReadOnlyBuffer();
    }

    public byte[] getBytes()
    {
        return _bytes;
    }

    public byte[] getBytesColonSpace()
    {
        return _bytesColonSpace;
    }

    public boolean is(String s)
    {
        return _string.equalsIgnoreCase(s);
    }

    public String asString()
    {
        return _string;
    }

    @Override
    public String toString()
    {
        return _string;
    }
}

