feat: smtp sending

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

lib/Smtp/Protocol/Reply.php

@@ -0,0 +1,74 @@
+<?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;
+
+/**
+ * A parsed SMTP reply: a 3-digit status code plus one or more text lines.
+ */
+final class Reply
+{
+    /**
+     * @param int          $code  3-digit SMTP status code
+     * @param list<string> $lines text portion of each reply line (code/separator stripped)
+     * @param string       $raw   the raw wire text (for diagnostics)
+     */
+    public function __construct(
+        private readonly int $code,
+        private readonly array $lines,
+        private readonly string $raw,
+    ) {}
+
+    public function code(): int
+    {
+        return $this->code;
+    }
+
+    /**
+     * @return list<string>
+     */
+    public function lines(): array
+    {
+        return $this->lines;
+    }
+
+    public function text(): string
+    {
+        return implode(' ', $this->lines);
+    }
+
+    public function raw(): string
+    {
+        return $this->raw;
+    }
+
+    /** 2xx — requested action completed. */
+    public function isPositiveCompletion(): bool
+    {
+        return $this->code >= 200 && $this->code < 300;
+    }
+
+    /** 3xx — more input required (e.g. DATA, AUTH challenge). */
+    public function isPositiveIntermediate(): bool
+    {
+        return $this->code >= 300 && $this->code < 400;
+    }
+
+    /** 4xx — transient negative completion (try again later). */
+    public function isTransientError(): bool
+    {
+        return $this->code >= 400 && $this->code < 500;
+    }
+
+    /** 5xx — permanent negative completion. */
+    public function isPermanentError(): bool
+    {
+        return $this->code >= 500;
+    }
+}