@TargetApi(Build.VERSION_CODES.KITKAT)
    @SuppressWarnings("BusyWait")
    @Override
    public ReadCaptchaResult onReadCaptcha(ReadCaptchaData data) throws HttpException, InvalidResponseException {
        AtomicReference<String> captcha = new AtomicReference<>("");

        WebView webView = data.webView;
        webView.post(() -> {
            WebSettings webSettings = webView.getSettings();
            webSettings.setJavaScriptEnabled(true);
            webView.setWebViewClient(new WebViewClient() {
                @TargetApi(Build.VERSION_CODES.KITKAT)
                public boolean shouldOverrideUrlLoading(WebView view, String url) {
                    view.post(() -> view.loadUrl(url));
                    return false;
                }
            });
        });

        boolean banned = REQUIREMENT_BANNED.equals(data.requirement);
        if (!banned) {
            String token = data.captchaPass != null ? data.captchaPass[0] : null;
            String pin = data.captchaPass != null ? data.captchaPass[1] : null;
            String captchaPassCookie = null;
            if (token != null || pin != null) {
                if (getCaptchaPassData(token, pin).equals(lastCaptchaPassData)) {
                    captchaPassCookie = lastCaptchaPassCookie;
                } else {
                    captchaPassCookie = readCaptchaPass(data, token, pin);
                }
            }
            if (captchaPassCookie != null) {
                CaptchaData captchaData = new CaptchaData();
                captchaData.put(CAPTCHA_DATA_KEY_PASS_COOKIE, captchaPassCookie);
                return new ReadCaptchaResult(CaptchaState.PASS, captchaData)
                        .setValidity(FourchanChanConfiguration.Captcha.Validity.LONG_LIFETIME);
            }
        }
        String captchaType = banned ? FourchanChanConfiguration.CAPTCHA_TYPE_RECAPTCHA_2 : data.captchaType;
        FourchanChanConfiguration configuration = FourchanChanConfiguration.get(this);
        FourchanChanLocator locator = FourchanChanLocator.get(this);
        ReadCaptchaResult result;
        if (FourchanChanConfiguration.CAPTCHA_TYPE_4CHAN_CAPTCHA.equals(captchaType)) {
            if (data.mayShowLoadButton) {
                return new ReadCaptchaResult(CaptchaState.NEED_LOAD, null);
            }
            String threadNumber = data.requirement == null ? data.threadNumber : "1";
            Uri.Builder builder = locator.createSysUri("captcha").buildUpon()
                    .appendQueryParameter("board", data.boardName);
            if (threadNumber != null) {
                builder.appendQueryParameter("thread_id", threadNumber);
            }
            Uri uri = builder.build();
            String challenge;
            Bitmap image;
            Bitmap background;
            int wait = 2000;
            while (true) {
                try {
                    webView.post(() -> webView.loadUrl(uri.toString()));
                    // waiting for the result above
                    try {
                        Thread.sleep(3000);
                    } catch (InterruptedException e) {
                        throw new RuntimeException(e);
                    }
                    webView.post(() -> webView.evaluateJavascript(
                            "(function() { return document.querySelector('pre').textContent; })();",
                            captcha::set));
                    // wait for the result above
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        throw new RuntimeException(e);
                    }
                    JSONObject jsonObject = new JSONObject(captcha.get().substring(1, captcha.get().length() - 1).replace("\\\"", "\""));
                    String error = jsonObject.optString("error");
                    if ("You have to wait a while before doing this again".equals(error)) {
                        try {
                            Thread.sleep(wait);
                        } catch (InterruptedException e) {
                            throw new HttpException(0, null);
                        }
                        wait += 1000;
                    } else {
                        challenge = jsonObject.getString("challenge");
                        byte[] imageBytes = Base64.decode(jsonObject.getString("img"), 0);
                        byte[] backgroundBytes = Base64.decode(jsonObject.optString("bg"), 0);
                        image = imageBytes.length == 0 ? null
                                : BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
                        background = backgroundBytes.length == 0 ? null
                                : BitmapFactory.decodeByteArray(backgroundBytes, 0, backgroundBytes.length);
                        break;
                    }
                } catch (JSONException e) {
                    throw new InvalidResponseException(e);
                }
            }