<?php
declare(strict_types=1);

namespace App\Helper;

class Excel
{
    public static function getColumnKey($index)
    {
        if ($index >= 256) {
            throw new \Exception('Too much Excel column!');
        }
        $keys = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'];
        if ($index < 26) {
            return $keys[$index];
        } else {
            $first = $index/26;
            $second = $index%26;
            return $keys[$first-1] . $keys[$second];
        }
    }

    public static function generateUniqueCode(array $params, string $identity, $length = 8)
    {
        $md5Code = md5(microtime(true) . json_encode($params) . $identity . rand(0, 9999));
        return substr($md5Code, 0, $length);
    }
}