refactor: smtp client

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

lib/Smtp/Protocol/ProtocolWriter.php

@@ -0,0 +1,53 @@
+<?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\Transport\ConnectionInterface;
+use Psr\Log\LoggerInterface;
+
+final class ProtocolWriter
+{
+    public function __construct(
+        private readonly ConnectionInterface $connection,
+        private readonly ?LoggerInterface $logger = null,
+    ) {}
+
+    /**
+     * Write a single command line, appending the CRLF terminator.
+     *
+     * @param bool $sensitive when true the payload is redacted from logs
+     *                        (used for AUTH credential exchanges)
+     */
+    public function writeLine(string $line, bool $sensitive = false): void
+    {
+        $this->logger?->debug('SMTP command sent: {command}', [
+            'command' => $sensitive ? $this->redact($line) : $line,
+        ]);
+
+        $this->connection->write($line . "\r\n");
+    }
+
+    /**
+     * Write raw bytes verbatim (e.g. the DATA payload). Never logged.
+     */
+    public function writeRaw(string $payload): void
+    {
+        $this->connection->write($payload);
+    }
+
+    private function redact(string $line): string
+    {
+        if (preg_match('/^(AUTH\s+\S+)(\s+.*)?$/i', $line, $matches) === 1) {
+            return $matches[1] . (isset($matches[2]) ? ' [REDACTED]' : '');
+        }
+
+        return '[REDACTED]';
+    }
+}