<?php

declare(strict_types=1);

/**
 * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */

namespace KTXM\ProviderImap\Smtp\Protocol;

use KTXM\ProviderImap\Smtp\SmtpException;
use KTXM\ProviderImap\Smtp\Transport\ConnectionInterface;
use Psr\Log\LoggerInterface;

/**
 * Reads SMTP replies, assembling multi-line responses.
 *
 * A multi-line reply repeats the status code on every line, using a hyphen
 * ("250-text") to indicate continuation and a space ("250 text") on the final
 * line. See RFC 5321 §4.2.
 */
final class ReplyReader
{
    public function __construct(
        private readonly ConnectionInterface $connection,
        private readonly ?LoggerInterface $logger = null,
    ) {}

    public function read(): Reply
    {
        $lines = [];
        $raw = '';
        $code = null;

        while (true) {
            $rawLine = $this->connection->readLine();
            $raw .= $rawLine;
            $trimmed = rtrim($rawLine, "\r\n");

            if (!preg_match('/^(\d{3})([ -]?)(.*)$/', $trimmed, $matches)) {
                throw new SmtpException(sprintf('Malformed SMTP reply line: %s', $trimmed));
            }

            $lineCode = (int) $matches[1];
            $separator = $matches[2];
            $lines[] = $matches[3];

            if ($code === null) {
                $code = $lineCode;
            } elseif ($lineCode !== $code) {
                throw new SmtpException(sprintf('Inconsistent SMTP reply code: %s', $trimmed));
            }

            // A space separator (or no separator) marks the final line.
            if ($separator !== '-') {
                break;
            }
        }

        $this->logger?->debug('SMTP reply received: {raw}', [
            'code' => $code,
            'raw' => rtrim($raw, "\r\n"),
        ]);

        return new Reply($code ?? 0, $lines, rtrim($raw, "\r\n"));
    }
}