const second = 1000;
const minute = second*60;
const hour = minute*60;
const day = hour*24;

const countdown = (target, heading) => {
    const now = new Date();
    const diff = target - now;

    const timeleft = {}; 
    timeleft.days = Math.trunc(diff/day);
    timeleft.hours = Math.trunc(diff%day/hour);
    timeleft.minutes = Math.trunc(diff%day%hour/minute);
    timeleft.seconds = Math.trunc(diff%day%hour%minute/second);

    const formatted = Object.keys(timeleft).map(unit => {
        // retrieve value, cast it to string and optionally pad it with a leading 0
        return timeleft[unit]
        .toString()
        .padStart(2, '0');
    });

    if (heading === 1 || formatted.filter(timespan => timespan.substr(0, 1) == '-').length === 0) {
        return `
<span style="font-size:${Math.round(100 - 60 * (4 - 4 / heading) / 4)}%">
${formatted[0]} Days<br>
${formatted[1]} Hours<br>
${formatted[2]} Minutes<br>
${formatted[3]} Seconds<br>
</span>
`;
    }
};

const hash_date = new Date(location.hash.substr(1));
const update_all = () => {
    let i = 0;
    const curDate = new Date();

    document.body.innerHTML = location
    .hash
    .split('#')
    .slice(1)
    .map(fragment => new Date(fragment))
    .sort((a, b) => b - a)
    .map(date => countdown(date, ++i))
    .join('');
}
update_all();
setInterval(update_all, 500);