func TestWebsockets(t *testing.T) {
	ts := StartTest(nil)
	defer ts.Close()

	globalConf := ts.Gw.GetConfig()
	globalConf.HttpServerOptions.EnableWebSockets = true
	ts.Gw.SetConfig(globalConf)

	ts.Gw.BuildAndLoadAPI(func(spec *APISpec) {
		spec.Proxy.ListenPath = "/"
	})

	baseURL := strings.Replace(ts.URL, "http://", "ws://", -1)
	url, err := url.Parse(baseURL)
	if err != nil {
		t.Fatalf("cannot parse url: %v", err)
	}

	conn, err := net.Dial("tcp", url.Host)
	if err != nil {
		t.Fatalf("cannot make connection: %v", err)
	}
	defer conn.Close()

	req := fmt.Sprintf(`GET %s/ws HTTP/1.1
Host: %s
Accept-Encoding: gzip, deflate, br, zstd
Sec-WebSocket-Version: 13
Sec-WebSocket-Extensions: permessage-deflate
Sec-WebSocket-Key: X62lCXELOHFcBBG72P2S2Q==
Connection: Upgrade, keep-alive
Upgrade: websocket

`, baseURL, url.Host)
	req = strings.Replace(req, "\n", "\r\n", -1)
	_, err = conn.Write([]byte(req))
	if err != nil {
		t.Fatalf("cannot write request: %v", err)
	}
	buf, err := bufio.NewReader(conn).ReadString('\n')
	if err != nil {
		t.Fatalf("cannot read response: %v", err)
	}
	if !strings.Contains(buf, "HTTP/1.1 101 Switching Protocols") {
		t.Error("Unexpected response:", buf)
	}

	_, _ = ts.Run(t, test.TestCase{
		Method: "GET",
		Path:   "/abc",
		Code:   http.StatusOK,
	})
}

func IsUpgrade(req *http.Request) (string, bool) {
	if !headerContainsTokenIgnoreCase(req.Header, headerConnection, "Upgrade") {
		return "", false
	}

	upgrade := strings.ToLower(strings.TrimSpace(req.Header.Get(headerUpgrade)))
	if upgrade != "" {
		return upgrade, true
	}

	return "", false
}

func headerContainsTokenIgnoreCase(h http.Header, key, token string) bool {
	for _, t := range headerTokens(h, key) {
		if strings.EqualFold(t, token) {
			return true
		}
	}
	return false
}

func headerTokens(h http.Header, key string) []string {
	key = textproto.CanonicalMIMEHeaderKey(key)
	var tokens []string
	for _, v := range h[key] {
		v = strings.TrimSpace(v)
		for _, t := range strings.Split(v, ",") {
			t = strings.TrimSpace(t)
			tokens = append(tokens, t)
		}
	}
	return tokens
}