function isIE() {
                return /*@cc_on!@*/false || !!document.documentMode;
            }

            function isEdge() {
                const ua = window.navigator.userAgent;
                const edge = ua.indexOf('Edge/');
                if (edge > 0) {
                    // Edge (IE 12+) => return version number
                    return parseInt(ua.substring(edge + 5, ua.indexOf('.', edge)), 10);
                }
                // other browser
                return false;
            }

            function isSafari() {
                const isSafari =
                    /constructor/i.test(window.HTMLElement) ||
                    (function(p) {
                        return p.toString() === '[object SafariRemoteNotification]';
                        // eslint-disable-next-line no-undef
                    })(!window['safari'] || (typeof safari !== 'undefined' && safari.pushNotification));
                return isSafari;
            }

            function isMac() {
                const ua = window.navigator.userAgent.toLowerCase();
                return /macintosh/i.test(ua);
            }

            function isMobile() {
                const ua = window.navigator.userAgent.toLowerCase();
                return /Android|webOS|iPhone|iPad|iPod|BlackBerry|BB|PlayBook|IEMobile|Windows Phone|Kindle|Silk|Opera Mini/i.test(ua);
            }

            function isAndroid() {
                const ua = window.navigator.userAgent.toLowerCase();
                return /(android|kindle|silk)/g.test(ua);
            }

            function isLinux() {
                const ua = window.navigator.userAgent.toLowerCase();
                return !isAndroid && /linux/.test(ua);
            }

            function getUrlParam(name, hashBased=false) {
                const url = hashBased ? window.location.hash.substr(1) : window.location.search;
                const urlParams = new URLSearchParams(url);
                return urlParams.get(name);
            }

            function isUtweb() {
                let ut;
                //remote
                if (window.location.hostname.match('utweb') || window.location.hostname.match('btweb')) {
                    ut = Boolean(window.location.hostname.match('utweb'));
                }
                //localhost
                if (ut === undefined) {
                    ut = window.location.port === '19575';
                }
                return ut;
            }

            function getWebApiBaseUrl() {
                let urlBase = 'http://127.0.0.1' + (isUtweb() ? ':19575' : ':38565');
                return urlBase + '/gui/';
            }

            function badBrowser() {
                const edgeVersion = isEdge();
                return isSafari() || isIE() || (edgeVersion && (edgeVersion < 17));
            }

            // GA3 - remove later
            function sendPing(action, label) {
                let source = getUrlParam('utm_source');
                let category = source ? 'share-' + source : 'share';
                ga('send', {
                    hitType: 'event',
                    eventCategory: category,
                    eventAction: action,
                    eventLabel: label,
                });
            }

            function sendGA4Ping(action, label) {
                let source = getUrlParam('utm_source');
                let category = source ? 'share-' + source : 'share';
                gtag('event', category, {
                    eventAction: action, 
                    eventLabel: label,
                });
            }

            function setDownloadText() {
                document.getElementById("os-download-text").innerHTML = isMac() ? '2. Run the .dmg file' : '2. Run the .exe file' ;
            }

            function setMagnetInfo() {
                // Store torrent magnet link into 'share' localstorage array
                const magnetLink = getUrlParam('link', true);
                if (magnetLink) {
                    let magnets = JSON.parse(window.localStorage.getItem('share') || '[]')
                    if (!magnets.includes(magnetLink)) {
                        magnets.push(magnetLink);
                        window.localStorage.setItem('share', JSON.stringify(magnets));
                    }
                }
            }

            function downloadClick() {
                let downloadUrl = '';
                if (isUtweb()) {
                    downloadUrl = isMac() ? 'https://www.utorrent.com/web/downloads/complete/track/stable/os/mac/' :
                                            'https://www.utorrent.com/web/downloads/complete/track/stable/os/win/';
                } else {
                    downloadUrl = 'https://www.bittorrent.com/downloads/complete/';
                }
                sendPing('click', 'download');
                sendGA4Ping('download_app');
                window.open(downloadUrl, '_self');
            }

            function addMagnetClick() {
                const magnetLink = getUrlParam('link', true);
                sendPing('click', 'magnet');
                sendGA4Ping('add_torrent');
                window.open(magnetLink, '_self');
            }

            function notSupported() {
                return isMobile() || isAndroid() || isLinux();
            }

            function isInstalled() {
                return window.localStorage.getItem('language');
            }

            function running() {
                // App running, redirect to index.html
                document.getElementById('running').style.display = 'flex';
                sendPing('pageload', 'app running')
                sendGA4Ping('pageload', 'app_running');
                let url = location.protocol + '//' + location.host + location.pathname;
                window.location = url.replace('share.html', 'index.html');
            }

            function notRunning() {
                // Check if app is installed by checking localstorage value
                // We cant check if installed on localhost browsers so assume not installed
                if (!isInstalled()) {
                    document.getElementById('not-installed').style.display = 'flex';
                    if (badBrowser()) {
                        document.getElementById('localhost-browser').style.display = 'flex';
                        sendPing('pageload', 'localhost browser');
                        sendGA4Ping('pageload', 'localhost_browser');

                    } else {
                        sendPing('pageload', 'app not installed')
                        sendGA4Ping('pageload', 'app_not_installed');
                    }
                } else {
                    document.getElementById('not-running').style.display = 'flex';
                    sendPing('pageload', 'app not running')
                    sendGA4Ping('pageload', 'app_not_running')
                }
            }

            function checkPresence() {
                // Check if on mobile/android/linux, etc
                if (notSupported()) {
                    document.getElementById('not-supported').style.display = 'flex';
                    let errorStr = 'device not supported'; // GA3 - remove later
                    let errorGA4Str = 'device_not_supported';
                    if (isLinux()) {
                        errorStr += ' (linux)';
                        errorGA4Str += '_linux';
                    } else if (isAndroid()) {
                        errorStr += ' (android)';
                        errorGA4Str += '_android';
                    } else if (isMobile()) {
                        errorStr += ' (mobile)';
                        errorGA4Str += '_mobile';
                    }
                    sendPing('pageload', errorStr)
                    sendGA4Ping('pageload', errorGA4Str);
                    return;
                }

                //Check if app is running by sending ping request (only in version >= 1.1.3)
                const pingUrl = getWebApiBaseUrl() + '?action=ping';
                fetch(pingUrl)
                    .then(function() {
                        running();
                    })
                    .catch(function() {
                        notRunning();
                    });
            }

            setDownloadText();
            setMagnetInfo();
            checkPresence();