Add a Download button below the currently viewing video on vimp.oth-regensburg.de/m/

vimp.oth-regensburg.de-m_add-video-download-button.user.js

// ==UserScript==
// @name        vimp.oth-regensburg.de-m_add-video-download-button.user
// @description Add a Download button below the currently viewing video on vimp.oth-regensburg.de/m/
// @match       *://vimp.oth-regensburg.de/m/*
// @version     1.0.0
// @grant       none
// @author      Lukas Wolfsteiner <lukas@wolfsteiner.media>
// ==/UserScript==

var downloadButtonParentSelector = document.querySelector('#siteContent > article > div.wrap.col-xs-12.col-sm-6.col-md-9.col-lg-9.col-xlg-9 > section.details > div:nth-child(1) > div.buttonpane.clearfix');
if (downloadButtonParentSelector !== null) {
    // element exists
    console.log('download button parent already exists');
    
    // check if download button already exists
    var downloadButtonSelector = document.querySelector('#siteContent > article > div.wrap.col-xs-12.col-sm-6.col-md-9.col-lg-9.col-xlg-9 > section.details > div:nth-child(1) > div.buttonpane.clearfix > a');
    if (downloadButtonSelector !== null) {
        // button already exists
        console.log('button already exists');
    } else {
        var videoKey = document.getElementById("sharekey").value;
        console.log(`videoKey: ${videoKey}`);

        // var videoUrl = `https://vimp.oth-regensburg.de/getMedium/${videoKey}.mp4`;
        var videoUrl = `https://vimp.oth-regensburg.de/getMedia.php?key=${videoKey}&type=mp4`;
        var buttonDownload = `<a class="btn btn-primary downloadMedia" href="${videoUrl}"><i class="icon-cloud-download"></i> Download</a>`;
        downloadButtonParentSelector.innerHTML += buttonDownload;
    }
}