404.html

---
layout: default
permalink: /404.html
---

<script>
function pad(num, size) {
    num = num.toString();
    while (num.length < size) num = "0" + num;
    return num;
}

function redirect() {
    let path = window.location.pathname;
    let mutated = false;
    const query = window.location.search;

    if (path.endsWith('/')) {
        path = path.slice(0, -1);
        window.location.replace('{{site.url}}' + path);
        return;
    }

    const re_bad_concat = new RegExp('^\/blog[0-9]+');
    let matches = path.match(re_bad_concat);
    if (matches) {
        path = path.replace('blog', 'blog/');
        window.location.replace('{{site.url}}' + path);
        return;
    }

    // Uber hack: when I migrated my wordpress posts to github pages I did
    // not realize the timestamps were not on my local time. This caused some
    // dates to be shifted by a day. Try the next day if we didn't find the
    // date.
    const re = new RegExp('^\/blog\/([0-9]+)\/([0-9]+)\/([0-9]+)\/[a-z\-]+');
    matches = path.match(re);

    if (matches) {
        const year = matches[1];
        const month = matches[2];
        const day = matches[3];
        const old_date_str = [year, month, day].join('/');
        const timestamp = Date.parse([year, month, day].join('-'));
        const shifted_timestamp = timestamp + 1000 * 60 * 60 * 24;
        const date = new Date(shifted_timestamp);

        const new_date_str = [
            date.getUTCFullYear(),
            pad(date.getUTCMonth() + 1, 2),
            pad(date.getUTCDate(), 2)
        ].join('/');
        path = path.replace(old_date_str, new_date_str);
        mutated = true;
    }

    if (query == '' && mutated) {
        window.location.replace('{{site.url}}' + path + '?redirected=1');
        return;
    }
}

redirect();
</script>

# 404

Page not found! :(