Simple and customisable command line progress bar in PHP

progressBar.php

<?php
/**
 * Create a progress bar
 *
 * @param int $total Max amount of items
 * @param int $width Width in characters of the progress bar (defaults to 100)
 * @param string $template Template to use,
 *        Available placeholders are %finished, %unfinished, %percent, %eta, %current and %total
 * @return callable A function that renders the bar and takes the current value as only argument
 *

 * // usage examples
 * $maxValue = 200;
 * $pb = progress_bar($maxValue);
 * for ($i = 0; $i <= $maxValue; $i++) {
 *     echo $pb($i);
 *     usleep(25000);
 * }
 * echo PHP_EOL;

 * // colors and changes to template
 * $custom = progress_bar(100, 50, "\033[42m%finished:' '\033[41m%unfinished\033[0m");
 * for ($i = 0; $i <= 100; $i++) {
 *     echo $custom($i);
 *     usleep(25000);
 * }
 * echo PHP_EOL;

 */
function progress_bar($total = 100, $width = 100, $template = '[%finished>%unfinished] %percent % (%current of %total) - ETA: %eta') {
    $symbols = array(
        'finished'      => '=',
        'unfinished'    => ' ',
        'eta'           => '?',
        'current'       => '#',
        'total'         => '#');

    $template = preg_replace_callback(
        '/%(' . implode('|', array_keys($symbols)) . '):(\'|")(.+?)\2/',
        function ($match) use (&$symbols) {
            $symbols[$match[1]] = $match[3];
            return '%' . $match[1];
        },
        $template
    );


    $startTime = null;
    $totalAmt  = $total;
    return function ($current) use ($template, $width, $totalAmt, $symbols, &$startTime) {
        if ($startTime === null) {
            $startTime = microtime(true);
            $percent = $current;
            $eta = $symbols['eta'];
        } else {
            $percent = max((int)(($current/$totalAmt) * 100),1);
            $elapsed = microtime(true) - $startTime;
            $eta = (int)((100 - $percent) * $elapsed / $percent);
        }

        $completed = max(round($percent * $width / 100),1);
        $view = str_replace(array(
                '%finished',
                '%unfinished',
                '%percent',
                '%eta',
                '%current',
                '%total'),
            array(
                str_repeat($symbols['finished'], $completed),
                str_repeat($symbols['unfinished'], $width - $completed),
                $percent,
                sprintf('%02dh %02dm %02ds', ($eta/3600),($eta/60%60), $eta%60),
                $current,
                $totalAmt),

            $template
        );
        return "\033[" . strlen($view) . 'D' . $view;
    };

}