element-call/src/auth/useRecaptcha.ts

/*
Copyright 2022 New Vector Ltd

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import { useEffect, useCallback, useRef, useState } from "react";
import { randomString } from "matrix-js-sdk/src/randomstring";
import { useTranslation } from "react-i18next";
import { logger } from "matrix-js-sdk/src/logger";

import { translatedError } from "../TranslatedError";
declare global {
  interface Window {
    mxOnRecaptchaLoaded: () => void;
  }
}

const RECAPTCHA_SCRIPT_URL =
  "https://www.recaptcha.net/recaptcha/api.js?onload=mxOnRecaptchaLoaded&render=explicit";

interface RecaptchaPromiseRef {
  resolve: (response: string) => void;
  reject: (error: Error) => void;
}

export function useRecaptcha(sitekey?: string): {
  execute: () => Promise<string>;
  reset: () => void;
  recaptchaId: string;
} {
  const { t } = useTranslation();
  const [recaptchaId] = useState(() => randomString(16));
  const promiseRef = useRef<RecaptchaPromiseRef>();

  useEffect(() => {
    if (!sitekey) return;

    const onRecaptchaLoaded = (): void => {
      if (!document.getElementById(recaptchaId)) return;

      window.grecaptcha.render(recaptchaId, {
        sitekey,
        size: "invisible",
        callback: (response: string) => promiseRef.current?.resolve(response),
        // eslint-disable-next-line @typescript-eslint/naming-convention
        "error-callback": () => promiseRef.current?.reject(new Error()),
      });
    };

    if (typeof window.grecaptcha?.render === "function") {
      onRecaptchaLoaded();
    } else {
      window.mxOnRecaptchaLoaded = onRecaptchaLoaded;

      if (!document.querySelector(`script[src="${RECAPTCHA_SCRIPT_URL}"]`)) {
        const scriptTag = document.createElement("script") as HTMLScriptElement;
        scriptTag.src = RECAPTCHA_SCRIPT_URL;
        scriptTag.async = true;
        document.body.appendChild(scriptTag);
      }
    }
  }, [recaptchaId, sitekey]);

  const execute = useCallback((): Promise<string> => {
    if (!sitekey) {
      return Promise.resolve("");
    }

    if (!window.grecaptcha) {
      logger.log("Recaptcha not loaded");
      return Promise.reject(translatedError("recaptcha_not_loaded", t));
    }

    return new Promise((resolve, reject) => {
      const observer = new MutationObserver((mutationsList) => {
        for (const item of mutationsList) {
          if ((item.target as HTMLElement)?.style?.visibility !== "visible") {
            reject(translatedError("recaptcha_dismissed", t));
            observer.disconnect();
            return;
          }
        }
      });

      promiseRef.current = {
        resolve: (value): void => {
          resolve(value);
          observer.disconnect();
        },
        reject: (error): void => {
          reject(error);
          observer.disconnect();
        },
      };

      window.grecaptcha.execute();

      const iframe = document.querySelector<HTMLIFrameElement>(
        'iframe[src*="recaptcha/api2/bframe"]',
      );

      if (iframe?.parentNode?.parentNode) {
        observer.observe(iframe?.parentNode?.parentNode, {
          attributes: true,
        });
      }
    });
  }, [sitekey, t]);

  const reset = useCallback(() => {
    window.grecaptcha?.reset();
  }, []);

  return { execute, reset, recaptchaId };
}