javascript:(async () => {
    /* Ensure the script is run on a valid GitHub repository page */
    const ensureForksPage = () => {
        const match = window.location.href.match(/^https:\/\/github\.com\/([^/]+)\/([^/]+)(\/forks\/?)?/);
        if (!match) {
            alert('Run this from a GitHub repository page.');
            throw new Error('Not on a valid GitHub repository page.');
        }
        if (!match[3]) {
            window.location.href = `https://github.com/${match[1]}/${match[2]}/forks`;
            throw new Error('Redirecting to the forks page.');
        }
        return { user: match[1], repo: match[2] };
    };

    /* Fetch the default branch of a repository */
    const getDefaultBranch = async (user, repo) => {
		let token = prompt("Insert your GITHUB_TOKEN. It won't be saved");
        const res = await fetch(`https://api.github.com/repos/${user}/${repo}`, { headers: { accept: 'application/json', authorization: `Bearer ${token}` } });
        if (!res.ok) throw new Error(`Failed to fetch default branch for ${user}/${repo}`);
        return (await res.json()).default_branch;
    };

    /* Fetch branch information */
    const fetchBranchInfo = async (user, repo, branch) => {
        try {
            const res = await fetch(`https://github.com/${user}/${repo}/branch-infobar/${branch}`, { headers: { accept: 'application/json' } });
            if (res.ok) return (await res.json()).refComparison;
        } catch (e) {
            console.error(`Error fetching branch info for ${user}/${repo}:`, e);
        }
        return null;
    };

    try {
        /* Ensure on the forks page and get main repository details */
        const { user: mainUser, repo: mainRepo } = ensureForksPage();
        const defaultBranch = await getDefaultBranch(mainUser, mainRepo);

        /* Process fork links */
        const forks = [...document.querySelectorAll('ul[data-view-component="true"] > li')];
        for (const fork of forks) {
            const repoLink = fork.querySelector('a[href*="/"]:nth-of-type(2)');
            const match = repoLink?.href.match(/github\.com\/([^/]+)\/([^/]+)/);
            if (!match) continue;

            const [_, user, repo] = match;
            let branchInfo = await fetchBranchInfo(user, repo, defaultBranch);
            if (!branchInfo) branchInfo = await fetchBranchInfo(user, repo, await getDefaultBranch(user, repo));

            if (branchInfo) {
                const { ahead, behind } = branchInfo;
                const info = `Ahead: <font color="#0c0">${ahead}</font>, Behind: <font color="red">${behind}</font>`;
                const infoDiv = document.createElement('div');
                infoDiv.innerHTML = info;
                infoDiv.style.marginTop = '10px';
                infoDiv.style.fontSize = 'small';
                fork.appendChild(infoDiv);
                if (ahead === 0) fork.style.display = 'none';
            }
        }
    } catch (e) {
        console.error('Error in bookmarklet execution:', e);
    }
})();