<?php

namespace app\http\middleware;

use Closure;
use app\Request;
use think\Response;

class EncryptDecryptMiddleware
{
    protected $secretKey = 'DUOs9QyBTDGdq3kPQcOnS6HEyp24He2h'; // 替换为你的密钥
    protected $cipher = 'AES-128-CBC';

    public function handle(Request $request, Closure $next): Response
    {
        // 解密请求数据
        if ($request->param('iv')) {
            $decryptedData = $this->decryptData($request->param('iv'));
            foreach ($decryptedData as $key => $value) {
                $request->param([$key => $value]);
            }
            // 继续执行下一个中间件或控制器
            $response = $next($request);

            // 加密响应数据
            $originalContent = $response->getContent();
            $encryptedContent = $this->encryptData(json_decode($originalContent, true));
            $response->setContent(json_encode($encryptedContent));
            return $response;
        } else {
            return $next($request);
        }
    }

    private function encryptData(array $data): array
    {
        $ivlen = openssl_cipher_iv_length($this->cipher);
        $iv = openssl_random_pseudo_bytes($ivlen);
        $ciphertext_raw = openssl_encrypt(json_encode($data), $this->cipher, $this->secretKey, OPENSSL_RAW_DATA, $iv);
        $hmac = hash_hmac('sha256', $ciphertext_raw, $this->secretKey, true);
        $ciphertext = base64_encode($iv . $hmac . $ciphertext_raw);

        return ['data' => $ciphertext];
    }

    private function decryptData(array $data): array
    {
        if (isset($data['data'])) {
            $c = base64_decode($data['data']);
            $ivlen = openssl_cipher_iv_length($this->cipher);
            $iv = substr($c, 0, $ivlen);
            $hmac = substr($c, $ivlen, $sha2len = 32);
            $ciphertext_raw = substr($c, $ivlen + $sha2len);
            $original_plaintext = openssl_decrypt($ciphertext_raw, $this->cipher, $this->secretKey, OPENSSL_RAW_DATA, $iv);
            $calcmac = hash_hmac('sha256', $ciphertext_raw, $this->secretKey, true);

            if (hash_equals($hmac, $calcmac)) {
                return json_decode($original_plaintext, true);
            }
        }

        return [];
    }
}