<?php

namespace App\Http\Services;

class SignRSA
{
    protected string $key;
    protected ?string $private;
    protected string $public;
    protected ?string $previousKey;
    protected ?string $previousPublic;

    public function __construct()
    {
        $this->key = base64_decode(config('rsa.key'));
        $this->private = str_replace('\n', "\n", config('rsa.private'));
        $this->public = str_replace('\n', "\n", config('rsa.public'));
        $this->previousKey = config('rsa.previous_key') ? base64_decode(config('rsa.previous_key')) : null;
        $this->previousPublic = config('rsa.previous_public') ? str_replace('\n', "\n", config('rsa.previous_public')) : null;
    }


    public function EncryptFunc($signdata): string
    {

        $sign = $this->SignData($signdata);

        return $this->EncryptedData($signdata . '|' . $sign, $this->key);
    }

    private function SignData($signdata = ''): string
    {

        openssl_sign($signdata, $result, $this->private, 'sha256WithRSAEncryption');

        return base64_encode($result);
    }

    private function EncryptedData($original_schema = '', $key_hash = ''): string
    {
        $encrypted_data = openssl_encrypt($original_schema, 'DES-EDE3', $key_hash, OPENSSL_RAW_DATA);

        return base64_encode($encrypted_data);
    }

    /*
     * Function Decrypt Data
     */

    public function DecryptFunc($data): string
    {
        if (!$data) {
            return false;
        }
        $encrypted_data = base64_decode($data);
        $verified = $this->Verify_Sign((string) $this->DecryptData($encrypted_data, $this->key), $this->public);

        if ($verified === false && $this->previousKey && $this->previousPublic) {
            $verified = $this->Verify_Sign((string) $this->DecryptData($encrypted_data, $this->previousKey), $this->previousPublic);
        }

        return $verified;
    }

    private function DecryptData($encrypted_data, $random_key): bool|string
    {
        return openssl_decrypt($encrypted_data, 'DES-EDE3', $random_key, OPENSSL_RAW_DATA);
    }

    private function Verify_Sign(string $decrypted_data, string $public): string|false
    {
        $data_arr = explode('|', $decrypted_data);

        if (!isset($data_arr[1])) {
            return false;
        }

        $signature = base64_decode($data_arr[1]);

        unset($data_arr[1]);

        $signature_data = implode('|', $data_arr);

        $verify = openssl_verify($signature_data, $signature, $public, 'sha256WithRSAEncryption');

        return $verify === 1 ? $signature_data : false;
    }

}