<?php

/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/

namespace Symfony\Component\Mime\Encoder;

/**
* @author Lars Strojny
*/
final class QpContentEncoder implements ContentEncoderInterface
{
public function encodeByteStream($stream, int $maxLineLength = 0): iterable
{
if (!\is_resource($stream)) {
throw new \TypeError(sprintf('Method "%s" takes a stream as a first argument.', __METHOD__));
}

// we don't use PHP stream filters here as the content should be small enough
yield $this->encodeString(stream_get_contents($stream), 'utf-8', 0, $maxLineLength);
}

public function getName(): string
{
return 'quoted-printable';
}

public function encodeString(string $string, ?string $charset = 'utf-8', int $firstLineOffset = 0, int $maxLineLength = 0): string
{
return $this->standardize(quoted_printable_encode($string));
}

/**
* Make sure CRLF is correct and HT/SPACE are in valid places.
*/
private function standardize(string $string): string
{
// transform CR or LF to CRLF
$string = preg_replace('~=0D(?!=0A)|(?<!=0D)=0A~', '=0D=0A', $string);
// transform =0D=0A to CRLF
$string = str_replace(["\t=0D=0A", ' =0D=0A', '=0D=0A'], ["=09\r\n", "=20\r\n", "\r\n"], $string);

switch (\ord(substr($string, -1))) {
case 0x09:
$string = substr_replace($string, '=09', -1);
break;
case 0x20:
$string = substr_replace($string, '=20', -1);
break;
}

return $string;
}
}