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    <h3>Editing: MessageConverter.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

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

namespace Symfony\Component\Mime;

use Symfony\Component\Mime\Exception\RuntimeException;
use Symfony\Component\Mime\Part\DataPart;
use Symfony\Component\Mime\Part\Multipart\AlternativePart;
use Symfony\Component\Mime\Part\Multipart\MixedPart;
use Symfony\Component\Mime\Part\Multipart\RelatedPart;
use Symfony\Component\Mime\Part\TextPart;

/**
 * @author Fabien Potencier &lt;fabien@symfony.com&gt;
 */
final class MessageConverter
{
    /**
     * @throws RuntimeException when unable to convert the message to an email
     */
    public static function toEmail(Message $message): Email
    {
        if ($message instanceof Email) {
            return $message;
        }

        // try to convert to a &quot;simple&quot; Email instance
        $body = $message-&gt;getBody();
        if ($body instanceof TextPart) {
            return self::createEmailFromTextPart($message, $body);
        }

        if ($body instanceof AlternativePart) {
            return self::createEmailFromAlternativePart($message, $body);
        }

        if ($body instanceof RelatedPart) {
            return self::createEmailFromRelatedPart($message, $body);
        }

        if ($body instanceof MixedPart) {
            $parts = $body-&gt;getParts();
            if ($parts[0] instanceof RelatedPart) {
                $email = self::createEmailFromRelatedPart($message, $parts[0]);
            } elseif ($parts[0] instanceof AlternativePart) {
                $email = self::createEmailFromAlternativePart($message, $parts[0]);
            } elseif ($parts[0] instanceof TextPart) {
                $email = self::createEmailFromTextPart($message, $parts[0]);
            } else {
                throw new RuntimeException(sprintf('Unable to create an Email from an instance of &quot;%s&quot; as the body is too complex.', get_debug_type($message)));
            }

            return self::addParts($email, \array_slice($parts, 1));
        }

        throw new RuntimeException(sprintf('Unable to create an Email from an instance of &quot;%s&quot; as the body is too complex.', get_debug_type($message)));
    }

    private static function createEmailFromTextPart(Message $message, TextPart $part): Email
    {
        if ('text' === $part-&gt;getMediaType() &amp;&amp; 'plain' === $part-&gt;getMediaSubtype()) {
            return (new Email(clone $message-&gt;getHeaders()))-&gt;text($part-&gt;getBody(), $part-&gt;getPreparedHeaders()-&gt;getHeaderParameter('Content-Type', 'charset') ?: 'utf-8');
        }
        if ('text' === $part-&gt;getMediaType() &amp;&amp; 'html' === $part-&gt;getMediaSubtype()) {
            return (new Email(clone $message-&gt;getHeaders()))-&gt;html($part-&gt;getBody(), $part-&gt;getPreparedHeaders()-&gt;getHeaderParameter('Content-Type', 'charset') ?: 'utf-8');
        }

        throw new RuntimeException(sprintf('Unable to create an Email from an instance of &quot;%s&quot; as the body is too complex.', get_debug_type($message)));
    }

    private static function createEmailFromAlternativePart(Message $message, AlternativePart $part): Email
    {
        $parts = $part-&gt;getParts();
        if (
            2 === \count($parts) &amp;&amp;
            $parts[0] instanceof TextPart &amp;&amp; 'text' === $parts[0]-&gt;getMediaType() &amp;&amp; 'plain' === $parts[0]-&gt;getMediaSubtype() &amp;&amp;
            $parts[1] instanceof TextPart &amp;&amp; 'text' === $parts[1]-&gt;getMediaType() &amp;&amp; 'html' === $parts[1]-&gt;getMediaSubtype()
        ) {
            return (new Email(clone $message-&gt;getHeaders()))
                -&gt;text($parts[0]-&gt;getBody(), $parts[0]-&gt;getPreparedHeaders()-&gt;getHeaderParameter('Content-Type', 'charset') ?: 'utf-8')
                -&gt;html($parts[1]-&gt;getBody(), $parts[1]-&gt;getPreparedHeaders()-&gt;getHeaderParameter('Content-Type', 'charset') ?: 'utf-8')
            ;
        }

        throw new RuntimeException(sprintf('Unable to create an Email from an instance of &quot;%s&quot; as the body is too complex.', get_debug_type($message)));
    }

    private static function createEmailFromRelatedPart(Message $message, RelatedPart $part): Email
    {
        $parts = $part-&gt;getParts();
        if ($parts[0] instanceof AlternativePart) {
            $email = self::createEmailFromAlternativePart($message, $parts[0]);
        } elseif ($parts[0] instanceof TextPart) {
            $email = self::createEmailFromTextPart($message, $parts[0]);
        } else {
            throw new RuntimeException(sprintf('Unable to create an Email from an instance of &quot;%s&quot; as the body is too complex.', get_debug_type($message)));
        }

        return self::addParts($email, \array_slice($parts, 1));
    }

    private static function addParts(Email $email, array $parts): Email
    {
        foreach ($parts as $part) {
            if (!$part instanceof DataPart) {
                throw new RuntimeException(sprintf('Unable to create an Email from an instance of &quot;%s&quot; as the body is too complex.', get_debug_type($email)));
            }

            $email-&gt;addPart($part);
        }

        return $email;
    }
}
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