<?php

namespace WP_Ultimo\Dependencies\Amp\ByteStream\Base64;

use WP_Ultimo\Dependencies\Amp\ByteStream\OutputStream;
use WP_Ultimo\Dependencies\Amp\ByteStream\StreamException;
use WP_Ultimo\Dependencies\Amp\Failure;
use WP_Ultimo\Dependencies\Amp\Promise;
final class Base64DecodingOutputStream implements OutputStream
{
    /** @var OutputStream */
    private $destination;
    /** @var string */
    private $buffer = '';
    /** @var int */
    private $offset = 0;
    public function __construct(OutputStream $destination)
    {
        $this->destination = $destination;
    }
    public function write(string $data) : Promise
    {
        $this->buffer .= $data;
        $length = \strlen($this->buffer);
        $chunk = \base64_decode(\substr($this->buffer, 0, $length - $length % 4), \true);
        if ($chunk === \false) {
            return new Failure(new StreamException('Invalid base64 near offset ' . $this->offset));
        }
        $this->offset += $length - $length % 4;
        $this->buffer = \substr($this->buffer, $length - $length % 4);
        return $this->destination->write($chunk);
    }
    public function end(string $finalData = "") : Promise
    {
        $this->offset += \strlen($this->buffer);
        $chunk = \base64_decode($this->buffer . $finalData, \true);
        if ($chunk === \false) {
            return new Failure(new StreamException('Invalid base64 near offset ' . $this->offset));
        }
        $this->buffer = '';
        return $this->destination->end($chunk);
    }
}