let r = document.createElement('a');
let hrefUrl = new URL(location.href);
let searchParams = new URLSearchParams(hrefUrl.search);
searchParams.delete('newtwitter')
hrefUrl.search = searchParams.toString();
r.href = hrefUrl.toString();
setInterval(() => {
    let hrefUrl = new URL(location.href);
    let searchParams = new URLSearchParams(hrefUrl.search);
    searchParams.delete('newtwitter')
    hrefUrl.search = searchParams.toString();
    r.href = hrefUrl.toString();

    let realPath = location.pathname.split('?')[0].split('#')[0];
    if (realPath.endsWith("/")) {
        realPath = realPath.slice(0, -1);
    }
    if(
        /^\/[A-z-0-9-_]{1,15}\/status\/\d{5,32}\/analytics$/.test(realPath) ||
        (realPath.startsWith('/i/') && realPath !== "/i/bookmarks" && !realPath.startsWith('/i/lists/')) ||
        realPath === '/explore' ||
        realPath === '/login' ||
        realPath === '/register' ||
        realPath === '/logout' ||
        realPath === '/messages' ||
        realPath.endsWith('/tos') ||
        realPath.endsWith('/privacy') ||
        realPath.startsWith('/account/') ||
        realPath.endsWith('/lists') ||
        realPath.endsWith('/topics') ||
        realPath.startsWith('/settings/')
    ) {
        r.hidden = true;
    } else {
        r.hidden = false;
    }
    
    if(!location.search.includes('newtwitter=true')) {
        let url = new URL(location.href);
        url.searchParams.set('newtwitter', 'true');
        history.replaceState(null, null, url.href);
    }
}, 500);
r.textContent = 'Open this page in OldTwitter';
r.style.cssText = 'position: fixed; top: 0; right: 10px; padding: 0.5em; background: #fff; color: #000; font-family: Arial, sans-serif;border-radius:3px;';
document.body.appendChild(r);

setTimeout(() => {
    let realPath = location.pathname.split('?')[0].split('#')[0];
    if (realPath.endsWith("/")) {
        realPath = realPath.slice(0, -1);
    }
    if(realPath === '/i/flow/login') {
        let i = setInterval(() => {
            let head = document.getElementById('modal-header');
            if(head) {
                clearInterval(i);
                let span = document.createElement('span');
                span.innerHTML = `OldTwitter relies on internal APIs that only work when you're logged in.<br>Please log in on this page to see old Twitter layout.`;
                span.style.cssText = `display: block;margin: 0.5em 0px;color: #fbfeff;font-family: TwitterChirp;background: rgb(0 161 255 / 10%);padding: 8px;border-radius: 5px;`;
                head.after(span);
            }
        }, 500);
    }
}, 1000);

(() => {
    let keysHeld = {};
    function processHotkeys() {
        if (keysHeld['Alt'] && keysHeld['Control'] && keysHeld['KeyO']) {
            let url = new URL(location.href);
            url.searchParams.delete('newtwitter');
            location.replace(url.href);
        }
    }
    window.addEventListener('keydown', (ev) => {
        let key = ev.code;
        if(key === 'AltLeft' || key === 'AltRight') key = 'Alt';
        if(key === 'ControlLeft' || key === 'ControlRight') key = 'Control';
        if(key === 'ShiftLeft' || key === 'ShiftRight') key = 'Shift';
        keysHeld[key] = true;

        processHotkeys();
    });

    window.addEventListener('keyup', (ev) => {
        let key = ev.code;
        if(key === 'AltLeft' || key === 'AltRight') key = 'Alt';
        if(key === 'ControlLeft' || key === 'ControlRight') key = 'Control';
        if(key === 'ShiftLeft' || key === 'ShiftRight') key = 'Shift';
        keysHeld[key] = true;
        processHotkeys();
        keysHeld[key] = false;
    });
})();

function modifyLink(a) {
    if(a.href && !a.href.includes('newtwitter=true')) {
        let url = new URL(a.href);
        url.searchParams.set('newtwitter', 'true');
        a.href = url.href;
    }
}

const linkObserver = new MutationObserver((mutations) => {
    mutations.forEach((mutation) => {
        if (mutation.type === 'childList' && mutation.addedNodes.length > 0) {
            mutation.addedNodes.forEach((node) => {
                if (node.nodeType === Node.ELEMENT_NODE) {
                    if(node.tagName === 'A') {
                        modifyLink(node);
                    }
                    node.querySelectorAll('a').forEach(modifyLink);
                }
            });
        }
    });
});

// Start observing the page for changes
linkObserver.observe(document.documentElement, { childList: true, subtree: true });