<?php

function toBase62($num) {
    $base62 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    $encoded = "";
    while ($num > 0) {
        $encoded = $base62[$num % 62] . $encoded;
        $num = floor($num / 62);
    }
    return $encoded;
}

function generateID() {
    $epochStart = strtotime("2020-01-01") * 1000; // Milliseconds since 2020
    $now = round(microtime(true) * 1000);
    $timestamp = ($now - $epochStart) % 1000000000000; // Keep last 12 digits

    $randomNum = rand(0, 99); // Random 2-digit number
    $finalNum = ($timestamp * 100) + $randomNum;

    return str_pad(toBase62($finalNum), 8, "0", STR_PAD_LEFT);
}

echo generateID(); // Example output: "A1b2C3D4"

?>