Cupom.php

<?php

namespace App\Helpers;

class Cupom
{
	public static function generate($len = 5)
	{
		$chars = strtoupper(md5(uniqid(mt_rand())));

		$str = '';

		for ($i = 0; $i < $len; $i++)
		{
			$position = mt_rand(0, strlen($chars));

			$str .= substr($chars, $position, 1);
		}

		return $str;
	}
}