Replace Youtube player with Invidious embeds

// ==UserScript==
// @name         Invidious Embed
// @namespace    http://tampermonkey.net/
// @version      1.0
// @description  Replace YouTube video player with Invidious embed
// @author       You
// @match        https://www.youtube.com/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Define the provider URL for easy user modifications
    const provider = 'https://invidious.fdn.fr';

    function embedInvidious() {
        const maxRetries = 10;
        let retryCount = 0;

        const createIframe = () => {
            // Remove any existing iframe
            const existingIframe = document.getElementById('invidious-embed');
            if (existingIframe) {
                existingIframe.remove();
            }

            // Extract video ID from the URL
            const videoID = window.location.search.split('v=')[1]?.split('&')[0];

            // Only proceed if a video ID is found
            if (!videoID) return;

            // Create an iframe element
            const iframe = document.createElement('iframe');
            // Use the provider constant in the iframe src attribute
            iframe.src = `${provider}/embed/${videoID}?quality=hd720&autoplay=1`;
            iframe.frameBorder = 0;
            iframe.style.position = 'absolute';
            iframe.style.maxWidth = '100vw';
            iframe.style.zIndex = 1000;
            iframe.id = 'invidious-embed';

            // Find the YouTube video player element
            const player = document.querySelector('.html5-video-player') || document.getElementById('movie_player');

            if (player) {
                // Obtain the position and size of the original player
                const rect = player.getBoundingClientRect();

                // Check if width and height are available; if not, retry after 1 second
                if (rect.width === 0 || rect.height === 0) {
                    if (retryCount < maxRetries) {
                        retryCount++;
                        setTimeout(createIframe, 1000);
                    }
                    return;
                }

                iframe.style.top = `${rect.top}px`;
                iframe.style.left = `${rect.left}px`;
                iframe.width = rect.width;
                iframe.height = rect.height;

                // Hide the YouTube video player
                player.style.opacity = '0';

                // Append the Invidious iframe to the body
                document.body.appendChild(iframe);
            }
        };

        // Call createIframe once initially
        createIframe();
    }

    // Initial embedding
    embedInvidious();

    // Create a MutationObserver instance
    const observer = new MutationObserver((mutations, observer) => {
        for(const mutation of mutations) {
            if (mutation.type === 'attributes') {
                embedInvidious();
            }
        }
    });

    // Options for the observer (which mutations to observe)
    const config = { attributes: true, childList: false, subtree: false };

    // Target for the observer
    const targetNode = document.body;

    // Start observing the target node
    observer.observe(targetNode, config);

    // Pause all videos every 100ms
    setInterval(() => {
        document.querySelectorAll('video').forEach(video => {
            video.pause();
        });
    }, 50);
})();