Take a number of seconds and return it in weeks/days/hours/minutes/seconds format. (like mIRC script's $duration identifier)

duration.php

<?php

/**
 * @param int $seconds
 * @return string
 */
function duration($seconds)
{
    foreach (['wk' => 604800, 'day' => 86400, 'hr' => 3600, 'min' => 60, 'sec' => 1] as $symbol => $subunit) {
        $value = (int) floor($seconds / $subunit);
        if ($value === 0) {
            continue;
        }
        $parts[] = $value . $symbol . ($value > 1 ? 's' : '');
        $seconds -= $value * $subunit;
    }
    return isset($parts) ? join(' ', $parts) : false;
}