More powerful/extensible notifications

- Notifications can be delivered in multiple ways (alert, email)
- Different notification types can implement interfaces to allow
themselves to be delivered in these various ways
- User preferences for each notification type/method combination are
automatically registered

src/Core/Notifications/NotificationServiceProvider.php

@@ -0,0 +1,35 @@
+<?php namespace Flarum\Core\Notifications;
+
+use Illuminate\Contracts\Events\Dispatcher;
+use Illuminate\Support\ServiceProvider;
+use Flarum\Core\Models\User;
+
+class NotificationServiceProvider extends ServiceProvider
+{
+    /**
+     * Bootstrap the application events.
+     *
+     * @return void
+     */
+    public function boot(Dispatcher $events)
+    {
+        $notifier = app('Flarum\Core\Notifications\Notifier');
+
+        $notifier->registerMethod('alert', 'Flarum\Core\Notifications\Senders\NotificationAlerter');
+        $notifier->registerMethod('email', 'Flarum\Core\Notifications\Senders\NotificationEmailer');
+
+        $notifier->registerType('Flarum\Core\Notifications\Types\DiscussionRenamedNotification', ['alert' => true]);
+
+        $events->subscribe('Flarum\Core\Handlers\Events\DiscussionRenamedNotifier');
+    }
+
+    public function register()
+    {
+        $this->app->bind(
+            'Flarum\Core\Repositories\NotificationRepositoryInterface',
+            'Flarum\Core\Repositories\EloquentNotificationRepository'
+        );
+
+        $this->app->singleton('Flarum\Core\Notifications\Notifier');
+    }
+}

src/Core/Notifications/Notifier.php

@@ -0,0 +1,59 @@
+<?php namespace Flarum\Core\Notifications;
+
+use Flarum\Core\Notifications\Types\Notification;
+use Flarum\Core\Models\Notification as NotificationModel;
+use Flarum\Core\Models\User;
+use Illuminate\Container\Container;
+
+class Notifier
+{
+    protected $methods = [];
+
+    protected $types = [];
+
+    protected $container;
+
+    public function __construct(Container $container)
+    {
+        $this->container = $container;
+    }
+
+    public function send(Notification $notification)
+    {
+        foreach ($this->methods as $method => $sender) {
+            $sender = $this->container->make($sender);
+            if ($notification->getRecipient()->shouldNotify($notification::getType(), $method) && $sender->compatibleWith($notification)) {
+                $sender->send($notification);
+            }
+        }
+    }
+
+    public function registerMethod($name, $class)
+    {
+        $this->methods[$name] = $class;
+    }
+
+    public function registerType($class, $defaultPreferences = [])
+    {
+        $this->types[] = $class;
+
+        NotificationModel::registerType($class);
+
+        foreach ($this->methods as $method => $sender) {
+            $sender = $this->container->make($sender);
+            if ($sender->compatibleWith($class)) {
+                User::registerPreference(User::notificationPreferenceKey($class::getType(), $method), 'boolval', array_get($defaultPreferences, $method, false));
+            }
+        }
+    }
+
+    public function getMethods()
+    {
+        return $this->methods;
+    }
+
+    public function getTypes()
+    {
+        return $this->types;
+    }
+}

src/Core/Notifications/Senders/NotificationAlerter.php

@@ -0,0 +1,25 @@
+<?php namespace Flarum\Core\Notifications\Senders;
+
+use Flarum\Core\Notifications\Types\Notification;
+use Flarum\Core\Models\Notification as NotificationModel;
+use ReflectionClass;
+
+class NotificationAlerter implements NotificationSender
+{
+    public function send(Notification $notification)
+    {
+        $model = NotificationModel::alert(
+            $notification->getRecipient()->id,
+            $notification::getType(),
+            $notification->getSender()->id,
+            $notification->getSubject()->id,
+            $notification->getAlertData()
+        );
+        $model->save();
+    }
+
+    public function compatibleWith($className)
+    {
+        return (new ReflectionClass($className))->implementsInterface('Flarum\Core\Notifications\Types\AlertableNotification');
+    }
+}

src/Core/Notifications/Senders/NotificationEmailer.php

@@ -0,0 +1,29 @@
+<?php namespace Flarum\Core\Notifications\Senders;
+
+use Flarum\Core\Notifications\Types\Notification;
+use Flarum\Core\Models\Forum;
+use Illuminate\Mail\Mailer;
+use ReflectionClass;
+
+class NotificationEmailer implements NotificationSender
+{
+    public function __construct(Mailer $mailer, Forum $forum)
+    {
+        $this->mailer = $mailer;
+        $this->forum = $forum;
+    }
+
+    public function send(Notification $notification)
+    {
+        $this->mailer->send($notification->getEmailView(), ['notification' => $notification], function ($message) use ($notification) {
+            $recipient = $notification->getRecipient();
+            $message->to($recipient->email, $recipient->username)
+                    ->subject('['.$this->forum->title.'] '.$notification->getEmailSubject());
+        });
+    }
+
+    public function compatibleWith($class)
+    {
+        return (new ReflectionClass($class))->implementsInterface('Flarum\Core\Notifications\Types\EmailableNotification');
+    }
+}

src/Core/Notifications/Senders/NotificationSender.php

@@ -0,0 +1,10 @@
+<?php namespace Flarum\Core\Notifications\Senders;
+
+use Flarum\Core\Notifications\Types\Notification;
+
+interface NotificationSender
+{
+    public function send(Notification $notification);
+
+    public function compatibleWith($class);
+}

src/Core/Notifications/Types/AlertableNotification.php

@@ -0,0 +1,8 @@
+<?php namespace Flarum\Core\Notifications\Types;
+
+interface AlertableNotification
+{
+    public function getAlertData();
+
+    public static function getType();
+}

src/Core/Notifications/Types/DiscussionRenamedNotification.php

@@ -0,0 +1,42 @@
+<?php namespace Flarum\Core\Notifications\Types;
+
+use Flarum\Core\Models\User;
+use Flarum\Core\Models\DiscussionRenamedPost;
+
+class DiscussionRenamedNotification extends Notification implements AlertableNotification
+{
+    public $post;
+
+    public $oldTitle;
+
+    public function __construct(User $recipient, User $sender, DiscussionRenamedPost $post, $oldTitle)
+    {
+        $this->post = $post;
+        $this->oldTitle = $oldTitle;
+
+        parent::__construct($recipient, $sender);
+    }
+
+    public function getSubject()
+    {
+        return $this->post->discussion;
+    }
+
+    public function getAlertData()
+    {
+        return [
+            'number'   => $this->post->number,
+            'oldTitle' => $this->oldTitle
+        ];
+    }
+
+    public static function getType()
+    {
+        return 'discussionRenamed';
+    }
+
+    public static function getSubjectModel()
+    {
+        return 'Flarum\Core\Models\Discussion';
+    }
+}

src/Core/Notifications/Types/EmailableNotification.php

@@ -0,0 +1,8 @@
+<?php namespace Flarum\Core\Notifications\Types;
+
+interface EmailableNotification
+{
+    public function getEmailView();
+
+    public function getEmailSubject();
+}

src/Core/Notifications/Types/Notification.php

@@ -0,0 +1,36 @@
+<?php namespace Flarum\Core\Notifications\Types;
+
+use Flarum\Core\Models\User;
+
+abstract class Notification
+{
+    protected $recipient;
+
+    protected $sender;
+
+    public function __construct(User $recipient, User $sender)
+    {
+        $this->recipient = $recipient;
+        $this->sender = $sender;
+    }
+
+    public function getRecipient()
+    {
+        return $this->recipient;
+    }
+
+    public function getSender()
+    {
+        return $this->sender;
+    }
+
+    public static function getType()
+    {
+        return null;
+    }
+
+    public static function getSubjectModel()
+    {
+        return null;
+    }
+}