Enum helper class, because why not?

Component/Subscription/SubscriptionEvent.php

@@ -0,0 +1,22 @@
+<?php
+/**
+ * Nucleus - XMPP Library for PHP
+ *
+ * Copyright (C) 2017, Some rights reserved.
+ *
+ * @author Kacper "Kadet" Donat <[email protected]>
+ *
+ * Contact with author:
+ * Xmpp: [email protected]
+ * E-mail: [email protected]
+ *
+ * From Kadet with love.
+ */
+
+namespace Kadet\Xmpp\Component\Subscription;
+
+
+class SubscriptionEvent
+{
+
+}

Stanza/Presence.php

@@ -17,6 +17,7 @@
 
 use Kadet\Xmpp\Exception\InvalidArgumentException;
 use Kadet\Xmpp\Jid;
+use Kadet\Xmpp\Stanza\Presence\Show;
 use Kadet\Xmpp\Utils\filter;
 use Kadet\Xmpp\Xml\XmlElement;
 
@@ -34,8 +35,6 @@
  */
 class Presence extends Stanza
 {
-    const POSSIBLE_SHOW = ['available', 'unavailable', 'chat', 'dnd', 'away', 'xa'];
-
     /**
      * Presence constructor.
      * @param array $options {
@@ -69,9 +68,9 @@ public function getShow()
      */
     public function setShow(string $show = 'available')
     {
-        if(!in_array($show, self::POSSIBLE_SHOW)) {
+        if(Show::valid($show)) {
             throw new InvalidArgumentException(format('$show must be one of: {possible}. {show} given.', [
-                'possible' => implode(',', self::POSSIBLE_SHOW),
+                'possible' => implode(',', Show::available()),
                 'show'     => $show
             ]));
         }

Stanza/Presence/Show.php

@@ -16,7 +16,9 @@
 namespace Kadet\Xmpp\Stanza\Presence;
 
 
-class Show
+use Kadet\Xmpp\Utils\Enum;
+
+class Show extends Enum
 {
     const AVAILABLE = "available";
 

Tests/Modules/Subscription/SubscriptionManagerTest.php

@@ -24,7 +24,7 @@
 use PHPUnit_Framework_MockObject_MockObject as Mock;
 
 use function Kadet\Xmpp\Utils\filter\{
-    all, not, pass
+    all, not
 };
 use function Kadet\Xmpp\Utils\filter\stanza\{
     to, type, id

Utils/Enum.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ * Nucleus - XMPP Library for PHP
+ *
+ * Copyright (C) 2017, Some rights reserved.
+ *
+ * @author Kacper "Kadet" Donat <[email protected]>
+ *
+ * Contact with author:
+ * Xmpp: [email protected]
+ * E-mail: [email protected]
+ *
+ * From Kadet with love.
+ */
+
+namespace Kadet\Xmpp\Utils;
+
+
+class Enum
+{
+    public static function available() {
+        static $reflection = null;
+        if(!$reflection) {
+            $reflection = new \ReflectionClass(self::class);
+        }
+
+        return $reflection->getConstants();
+    }
+
+    public static function valid($value) {
+        return in_array($value, self::available());
+    }
+}

XmppClient.php

@@ -267,7 +267,7 @@ public function send(Stanza $stanza) : ExtendedPromiseInterface
             } else {
                 $deferred->resolve($stanza);
             }
-        }, with\stanza\id($stanza->id));
+         }, with\stanza\id($stanza->id));
         $this->write($stanza);
 
         return $deferred->promise();