<?php

/*
 * This file is part of Chevereto.
 *
 * (c) Rodolfo Berrios <rodolfo@chevereto.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Chevereto\Encryption;

use Chevereto\Encryption\Interfaces\DecodeInterface;
use Chevereto\Encryption\Interfaces\EncryptionInterface;

final class Decode implements DecodeInterface
{
    private string $decoded;

    private string $nonce;

    private string $cipherText;

    public function __construct(string $encoded)
    {
        $isBase64 = false;
        $this->decoded = $encoded;
        if (preg_match('/^[a-zA-Z0-9\/+]*={0,2}$/', $encoded)) {
            $decoded = base64_decode($encoded, true);
            if ($decoded !== false) {
                $isBase64 = true;
                $this->decoded = $decoded;
            }
        }
        if ($isBase64) {
            $this->nonce = mb_substr(
                $this->decoded,
                0,
                EncryptionInterface::NONCE_LENGTH,
                self::ENCODING
            );
            assertNonce($this->nonce);
            $this->cipherText = mb_substr(
                $this->decoded,
                EncryptionInterface::NONCE_LENGTH,
                null,
                self::ENCODING
            );
        } else {
            $this->nonce = substr($this->decoded, 0, EncryptionInterface::NONCE_LENGTH);
            assertNonce($this->nonce);
            $this->cipherText = substr($this->decoded, EncryptionInterface::NONCE_LENGTH);
        }
    }

    public function __toString(): string
    {
        return $this->decoded;
    }

    public function nonce(): string
    {
        return $this->nonce;
    }

    public function cipherText(): string
    {
        return $this->cipherText;
    }
}