feat: dispatch a merging event

src/Api/Commands/MergeDiscussionHandler.php

@@ -17,6 +17,7 @@
 use Flarum\Post\Post;
 use Flarum\User\UserRepository;
 use FoF\MergeDiscussions\Events\DiscussionWasMerged;
+use FoF\MergeDiscussions\Events\MergingDiscussions;
 use FoF\MergeDiscussions\Models\Redirection;
 use FoF\MergeDiscussions\Validators\MergeDiscussionValidator;
 use Illuminate\Database\Eloquent\Collection;
@@ -93,7 +94,7 @@ public function handle(MergeDiscussion $command)
         }
 
         if ($command->merge) {
-            resolve('db.connection')->transaction(function () use ($discussions, $discussion, $command) {
+            resolve('db.connection')->transaction(function () use ($discussions, $discussion, $command, $posts) {
                 try {
                     // Set the relations using the bumped `number`, so we are sure we won't hit any integrity constraints
                     $discussion->push();
@@ -111,6 +112,10 @@ public function handle(MergeDiscussion $command)
                     }
                 }
 
+                $this->events->dispatch(
+                    new MergingDiscussions($command->actor, $posts, $discussion, $discussions)
+                );
+
                 try {
                     $discussion
                         ->refresh()

src/Events/MergingDiscussions.php

@@ -0,0 +1,48 @@
+<?php
+
+/*
+ * This file is part of fof/merge-discussions.
+ *
+ * Copyright (c) FriendsOfFlarum.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace FoF\MergeDiscussions\Events;
+
+use Flarum\Discussion\Discussion;
+use Flarum\Post\Post;
+use Flarum\User\User;
+use Illuminate\Support\Collection;
+
+class MergingDiscussions
+{
+    /**
+     * @var User
+     */
+    public $actor;
+
+    /**
+     * @var Post[]|Collection
+     */
+    public $posts;
+
+    /**
+     * @var Discussion
+     */
+    public $discussion;
+
+    /**
+     * @var Discussion[]|Collection Discussion
+     */
+    public $mergedDiscussions;
+
+    public function __construct(User $actor, Collection $posts, Discussion $discussion, Collection $mergedDiscussions)
+    {
+        $this->actor = $actor;
+        $this->posts = $posts;
+        $this->discussion = $discussion;
+        $this->mergedDiscussions = $mergedDiscussions;
+    }
+}