<?php

namespace BRSystems\Core\Library\cDefuseCrypto;

use BRSystems\Core\Library\cNumbers\cNumbers;
use Defuse\Crypto\Crypto;
use Defuse\Crypto\Key;
use Exception;

/**
 * CMS/APP cDefuseCrypto module
 *
 * @category LIB cDefuseCrypto
 * @author Mareks Keišs <mareks.keiss@brsystems.lv>
 * @since Version 1.0
 */
class cDefuseCrypto
{
    private $sName;
    private $oKey;
    private $bStatus = true;

    /**
     * Class constructor
     */
    public function __construct() {

        // echo "openssl version text: " . OPENSSL_VERSION_TEXT . "\n";
        // echo "openssl version number:  " . OPENSSL_VERSION_NUMBER . "\n";

        $this->sName = get_class();

        if(version_compare(PHP_VERSION, '7.0.0') >= 0)
            require_once 'php-encryption-master/defuse-crypto.phar';
        else
            require_once 'php-encryption-master/defuse-crypto-php5.phar';

        // Set my secret pass
        $this->oKey = Key::loadFromAsciiSafeString("def0000030259bf916c771f1beb1b7d9767033d054f6a639d860d67c61ca34d63ec3ee8ffbce52f73b0ea6c6e86d12ef20059c6419d9e44a57dce995515a11eb02da45df");

        // Check if necessary environment is ok
        try{
            if(!in_array('aes-256-ecb', openssl_get_cipher_methods(), true))
                trigger_error("cDefuseCrypto couldn't initiate class due to missing 'aes-256-ecb' cipher method ---> Encryption failed!");

            if(!strlen($sCipherData = Crypto::encrypt('test', $this->oKey, false)))
                trigger_error("cDefuseCrypto couldn't initiate class due to missing parts ---> Encryption failed!");

        }catch (Exception $e){
            $this->bStatus = false;
            trigger_error('cDefuseCrypto couldnt initiate class due to missing parts ---> switching to older data encryption');
        }

    }

    /**
     * Function to encrypt data
     *
     * @author Mareks Keišs <mareks.keiss@brsystems.lv>
     * @category cDefuseCrypto
     * @param string $msg - data to encrypt
     * @param bool|cDefuseCrypto $oKey - encrypt key
     * @return string - encrypted string
     */
    public function encrypt($msg, $oKey = null){

        $ciphertext = '';
        if($this->bStatus){
            $ciphertext = Crypto::encrypt((string)$msg, ($oKey ? $oKey : $this->oKey), false);
            $ciphertext = $this->safeBase64encode($ciphertext);
        }
        return $ciphertext;

    }

    /**
     * Function to decrypt data
     *
     * @author Mareks Keišs <mareks.keiss@brsystems.lv>
     * @category cDefuseCrypto
     * @param string $sCipherText - encrypted data to decrypt
     * @param bool|cDefuseCrypto $oKey - encrypt key
     * @return string - decrypted string
     */
    public function decrypt($sCipherText, $oKey = null){

        $sMsg = '';
        if($this->bStatus){
            $sCipherText = $this->safeBase64decode($sCipherText);
            $sMsg = Crypto::decrypt($sCipherText, ($oKey ? $oKey : $this->oKey), false);
        }
        return $sMsg;

    }

    /**
     * Function to create new Defuse encryption key / load key rom string
     *
     * @author Mareks Keišs <mareks.keiss@brsystems.lv>
     * @category cDefuseCrypto
     * @return string - encrypted string
     */
    public function createNewRandomDefuseKey(){
        return Key::createNewRandomKey()->saveToAsciiSafeString();
    }
    public function loadDefuseKeyFromString($sKey){
        return Key::loadFromAsciiSafeString($sKey);
    }

    /**
     * Function to safely encode base 64 for url
     *
     * @author Mareks Keišs <mareks.keiss@brsystems.lv>
     * @category cDefuseCrypto
     * @param string $data - data to encrypt
     * @return string - encrypted string
     */
    public function safeBase64encode($data){

        return rtrim(strtr(base64_encode($data), '+/', '-_'), '=');

    }

    /**
     * Function to safely decode base 64 for url
     *
     * @author Mareks Keišs <mareks.keiss@brsystems.lv>
     * @category cDefuseCrypto
     * @param string $data - encrypted data to decrypt
     * @return string - decrypted string
     */
    public function safeBase64decode($data){

        return base64_decode(str_pad(strtr($data, '-_', '+/'), strlen($data) % 4, '=', STR_PAD_RIGHT));

    }

    /**
     * Function to generate unique token for CSRF (Cross-site request forgery)
     *
     * @author Mareks Keišs <mareks.keiss@brsystems.lv>
     * @category cDefuseCrypto
     * @return string - sha1 encrypted string
     */
    public static function genToken(){

        return sha1(time() . cNumbers::getRandomChString());

    }
}