<?php

/* - (string) tos_stardate
 *
 * Random 4-numbers (progressively higher throughout an episode), followed by a single decimal place representing time of day.
 */
function tos_stardate($timestamp = NULL) {
    if(!$timestamp) $timestamp = time();
    $hour = date('G', $timestamp);
    $percent = intval($hour) / 24;
    return mt_rand(1000,9999) . '.' . round($percent * 10);
}

/* - (string) tng_stardate
 *
 * Century number - 20 followed by season number of show, followed by 3 random numbers (in progression throughout an episode),
 * followed by a decimal and day of year.
 */
function tng_stardate($season = 1, $timestamp = NULL) {
    if(!$timestamp) $timestamp = time();

    $century = intval(substr(date('Y', $timestamp), 0, 2)) + 1;
    $century = $century - 20;

    return $century . $season . mt_rand(000, 999) . '.' . date('z', $timestamp);
}

/* - (string) new_stardate
 *
 * Easy: year, decimal, day-of-year
 */
function new_stardate($timestamp = NULL) {
    if(!$timestamp) $timestamp = time();

    return date('Y.z', $timestamp);
}

echo 'The Original Series: ' . tos_stardate() . '<br />'
     . 'The Next Generation: ' . tng_stardate(4) . '<br />'
     . 'New Star Trek: ' . new_stardate();
?>