<?php

/**
 * Class HRCEncryptor
 *
 * For key need use Encryption::format($company->code)
 */
class HRCEncryptor
{
    const IV = 'AiFFzylt4NjaOflK';

    public static function format($key)
    {
        $reverse = 0;
        $n = $key;
        while ($n > 0) {
            $reverse = $reverse * 10;
            $reverse = $reverse + $n % 10;
            $n = (int)($n / 10);
        }

        return pow(($key + $reverse), 2);
    }

    public static function key($key)
    {
        $key = self::format($key);
        while (strlen($key) < 32) {
            $key .= $key;
        }

        return substr($key, 0, 32);
    }

    public static function encrypt($content, $key)
    {
        return base64_encode(openssl_encrypt($content, 'aes-256-cbc', self::key($key), OPENSSL_RAW_DATA, self::IV));
    }

    public static function decrypt($content, $key)
    {
        return openssl_decrypt(base64_decode($content), 'aes-256-cbc', self::key($key), OPENSSL_RAW_DATA, self::IV);
    }

    public static function sign($content, $key)
    {
        return md5($key . md5($content));
    }

    public static function check($signature, $public_key)
    {
        $fields = $_REQUEST;
        ksort($fields);

        $params = [];
        foreach ($fields as $key => $value) {
            if ($key != 'signature') {
                $params[] = $key . '=' . $value;
            }
        }

        $check = md5($public_key . md5(implode('&', $params)));

        return $check == $signature;
    }

}