TianLiangZhou/shrimp-wechat-sdk

<?php

declare(strict_types=1);

namespace Shrimp\Support;

use InvalidArgumentException;

/**
 * Class Aes
 * @package Shrimp\Support
 */
class Aes
{
    /**
     * @param string $text
     * @param string $key
     * @param string $iv
     * @param int $option
     * @return string
     */
    public static function encrypt(string $text, string $key, string $iv = '', int $option = OPENSSL_RAW_DATA): string
    {
        static::validateKey($key);
        $iv && static::validateIv($iv);

        return openssl_encrypt($text, self::getMode($key), $key, $option, $iv);
    }

    /**
     * @param string $cipherText
     * @param string $key
     * @param string $iv
     * @param int $option
     * @param null $method
     * @return string
     */
    public static function decrypt(
        string $cipherText,
        string $key,
        string $iv = '',
        int $option = OPENSSL_RAW_DATA,
        $method = null
    ): string {
        self::validateKey($key);
        $iv && self::validateIv($iv);

        return openssl_decrypt($cipherText, $method ?: self::getMode($key), $key, $option, $iv);
    }

    /**
     * @param string $key
     *
     * @return string
     */
    public static function getMode($key)
    {
        return 'AES-'.(8 * strlen($key)).'-CBC';
    }

    /**
     * @param string $key
     */
    public static function validateKey(string $key)
    {
        if (!in_array(strlen($key), [16, 24, 32], true)) {
            throw new InvalidArgumentException(
                sprintf('Key length must be 16, 24, or 32 bytes; got key len (%s).', strlen($key))
            );
        }
    }

    /**
     * @param string $iv
     *
     * @throws InvalidArgumentException
     */
    public static function validateIv(string $iv)
    {
        if (strlen($iv) !== 16) {
            throw new InvalidArgumentException('IV length must be 16 bytes.');
        }
    }
}