Allow author to delete discussion if there are no replies

Also disallow the first post in a discussion to be deleted or hidden
(thus preventing discussions with zero posts)

closes flarum/core#90 closes flarum/core#92

js/forum/src/initializers/post-controls.js

@@ -37,11 +37,14 @@ export default function(app) {
         items.add('restore', ActionButton.component({ icon: 'reply', label: 'Restore', onclick: restoreAction.bind(this) }));
       } else {
         items.add('edit', ActionButton.component({ icon: 'pencil', label: 'Edit', onclick: editAction.bind(this) }));
+
+        if (this.number() != 1) {
           items.add('hide', ActionButton.component({ icon: 'times', label: 'Delete', onclick: hideAction.bind(this) }));
         }
       }
+    }
 
-    if ((this.contentType() !== 'comment' || this.isHidden()) && this.canDelete()) {
+    if ((this.contentType() !== 'comment' || this.isHidden()) && this.canDelete() && this.number() != 1) {
       items.add('delete', ActionButton.component({ icon: 'times', label: 'Delete', onclick: deleteAction.bind(this) }));
     }
 

migrations/2015_02_24_000000_create_discussions_table.php

@@ -19,6 +19,7 @@ class CreateDiscussionsTable extends Migration
             $table->increments('id');
             $table->string('title', 200);
             $table->integer('comments_count')->unsigned()->default(0);
+            $table->integer('participants_count')->unsigned()->default(0);
             $table->integer('number_index')->unsigned()->default(0);
 
             $table->dateTime('start_time');

src/Api/Serializers/DiscussionSerializer.php

@@ -17,6 +17,7 @@ class DiscussionSerializer extends DiscussionBasicSerializer
 
         $attributes += [
             'commentsCount'     => (int) $discussion->comments_count,
+            'participantsCount' => (int) $discussion->participants_count,
             'startTime'         => $discussion->start_time->toRFC3339String(),
             'lastTime'          => $discussion->last_time ? $discussion->last_time->toRFC3339String() : null,
             'lastPostNumber'    => $discussion->last_post_number,

src/Core/Handlers/Commands/EditPostCommandHandler.php

@@ -3,6 +3,7 @@
 use Flarum\Core\Repositories\PostRepositoryInterface as PostRepository;
 use Flarum\Core\Events\PostWillBeSaved;
 use Flarum\Core\Support\DispatchesEvents;
+use Flarum\Core\Models\CommentPost;
 
 class EditPostCommandHandler
 {
@@ -22,6 +23,7 @@ class EditPostCommandHandler
 
         $post->assertCan($user, 'edit');
 
+        if ($post instanceof CommentPost) {
             if (isset($command->data['content'])) {
                 $post->revise($command->data['content'], $user);
             }
@@ -33,6 +35,7 @@ class EditPostCommandHandler
                     $post->restore($user);
                 }
             }
+        }
 
         event(new PostWillBeSaved($post, $command));
 

src/Core/Handlers/Events/DiscussionMetadataUpdater.php

@@ -28,6 +28,7 @@ class DiscussionMetadataUpdater
 
         $discussion->comments_count++;
         $discussion->setLastPost($event->post);
+        $discussion->refreshParticipantsCount();
         $discussion->save();
     }
 
@@ -46,6 +47,7 @@ class DiscussionMetadataUpdater
         $discussion = $event->post->discussion;
 
         $discussion->refreshCommentsCount();
+        $discussion->refreshParticipantsCount();
         $discussion->refreshLastPost();
         $discussion->save();
     }
@@ -56,6 +58,7 @@ class DiscussionMetadataUpdater
 
         if ($discussion->exists) {
             $discussion->refreshCommentsCount();
+            $discussion->refreshParticipantsCount();
 
             if ($discussion->last_post_id == $post->id) {
                 $discussion->refreshLastPost();

src/Core/Models/CommentPost.php

@@ -5,6 +5,7 @@ use Flarum\Core\Events\PostWasPosted;
 use Flarum\Core\Events\PostWasRevised;
 use Flarum\Core\Events\PostWasHidden;
 use Flarum\Core\Events\PostWasRestored;
+use Flarum\Core\Exceptions\ValidationFailureException;
 
 class CommentPost extends Post
 {
@@ -75,6 +76,10 @@ class CommentPost extends Post
      */
     public function hide($user)
     {
+        if ($this->number == 1) {
+            throw new ValidationFailureException;
+        }
+
         if (! $this->hide_time) {
             $this->hide_time = time();
             $this->hide_user_id = $user->id;
@@ -93,6 +98,10 @@ class CommentPost extends Post
      */
     public function restore($user)
     {
+        if ($this->number == 1) {
+            throw new ValidationFailureException;
+        }
+
         if ($this->hide_time !== null) {
             $this->hide_time = null;
             $this->hide_user_id = null;

src/Core/Models/Discussion.php

@@ -23,6 +23,7 @@ class Discussion extends Model
         'title'              => 'required',
         'start_time'         => 'required|date',
         'comments_count'     => 'integer',
+        'participants_count' => 'integer',
         'start_user_id'      => 'integer',
         'start_post_id'      => 'integer',
         'last_time'          => 'date',
@@ -175,6 +176,18 @@ class Discussion extends Model
         return $this;
     }
 
+    /**
+     * Refresh the discussion's participants count.
+     *
+     * @return $this
+     */
+    public function refreshParticipantsCount()
+    {
+        $this->participants_count = $this->participants()->count('users.id');
+
+        return $this;
+    }
+
     /**
      * Specify that a post was added to this discussion during this request
      * for later retrieval.
@@ -255,6 +268,16 @@ class Discussion extends Model
         return $this->posts()->where('type', 'comment')->whereNull('hide_time');
     }
 
+    /**
+     * Define the relationship with the discussion's participants.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\HasMany
+     */
+    public function participants()
+    {
+        return User::join('posts', 'posts.user_id', '=', 'users.id')->where('posts.discussion_id', $this->id)->select('users.*')->distinct();
+    }
+
     /**
      * Define the relationship with the discussion's first post.
      *

src/Core/Models/Post.php

@@ -2,6 +2,7 @@
 
 use Flarum\Core\Events\PostWasDeleted;
 use Flarum\Core\Support\Locked;
+use Flarum\Core\Exceptions\ValidationFailureException;
 
 class Post extends Model
 {
@@ -74,6 +75,12 @@ class Post extends Model
             $post->discussion->save();
         });
 
+        static::deleting(function ($post) {
+            if ($post->number == 1) {
+                throw new ValidationFailureException;
+            }
+        });
+
         static::deleted(function ($post) {
             $post->raise(new PostWasDeleted($post));
         });