provider_imap/lib/Client/Protocol/FetchResultReader.php

<?php

declare(strict_types=1);

namespace KTXM\ProviderImap\Client\Protocol;

use Generator;
use KTXM\ProviderImap\Client\ImapException;
use KTXM\ProviderImap\Client\Message;
use KTXM\ProviderImap\Client\Protocol\Parser\FetchMessageParser;
use KTXM\ProviderImap\Client\Protocol\Response\TaggedResponse;
use KTXM\ProviderImap\Client\Protocol\Response\UntaggedResponse;

/**
 * Reads FETCH messages from a response stream and validates command completion.
 */
final class FetchResultReader
{
    public function readOne(ResponseStream $responses): Message
    {
        $message = null;

        foreach ($this->readMany($responses) as $summary) {
            if ($message !== null) {
                throw new ImapException('FETCH returned multiple messages for a single-message request.');
            }

            $message = $summary;
        }

        if ($message === null) {
            throw new ImapException('FETCH did not return a message summary.');
        }

        return $message;
    }

    /**
     * Consume the generator fully to reach and validate the tagged completion.
     *
     * @return Generator<int, Message>
     */
    public function readMany(ResponseStream $responses): Generator
    {
        foreach ($responses as $response) {
            if ($response instanceof UntaggedResponse && FetchMessageParser::isFetchMessage($response->raw())) {
                yield FetchMessageParser::parse($response->raw());
                continue;
            }

            if ($response instanceof TaggedResponse) {
                if (!$response->isOk()) {
                    throw new ImapException('FETCH failed: ' . $response->text());
                }

                return;
            }
        }

        throw new ImapException('FETCH did not receive a tagged completion response.');
    }
}