Implement IMAP email-to-ticket gateway

NotificationEmailProxy.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+/** Used only while Support creates a ticket for an imported message. */
+class NotificationEmailProxy
+{
+    public function __construct(private object $email, private \Closure $acknowledge) {}
+
+    public function sendTemplate(array $data): mixed
+    {
+        if (($data['code'] ?? '') === 'mod_support_ticket_open') {
+            return ($this->acknowledge)($data);
+        }
+        // The canned reply remains in the ticket. Send the ticket-number
+        // acknowledgement instead of a second automatic canned-reply email.
+        if (($data['code'] ?? '') === 'mod_support_ticket_staff_reply') {
+            return false;
+        }
+
+        return $this->email->sendTemplate($data);
+    }
+
+    public function __call(string $method, array $arguments): mixed
+    {
+        return $this->email->$method(...$arguments);
+    }
+}