Add support for mentions to the editor

app/Concerns/HasMentions.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Concerns;
+
+use App\Models\ReplyAble;
+use App\Models\User;
+use Illuminate\Support\Collection;
+
+trait HasMentions
+{
+    public function mentionedIn(): ReplyAble
+    {
+        if ($this instanceof ReplyAble) {
+            return $this;
+        }
+
+        return $this->replyAble();
+    }
+
+    public function getMentionedUsers(): Collection
+    {
+        preg_match_all('/@([a-z\d](?:[a-z\d]|-(?=[a-z\d])){0,38}(?!\w))/', $this->body(), $matches);
+
+        return User::whereIn('username', $matches[1])->get();
+    }
+}

app/Concerns/ProvidesSubscriptions.php

@@ -5,6 +5,7 @@
 use App\Models\Subscription;
 use App\Models\User;
 use Illuminate\Database\Eloquent\Relations\MorphMany;
+use Ramsey\Uuid\Uuid;
 
 trait ProvidesSubscriptions
 {
@@ -38,4 +39,14 @@ public function hasSubscriber(User $user): bool
             ->where('user_id', $user->id())
             ->exists();
     }
+
+    public function subscribe(User $user): Subscription
+    {
+        $subscription = new Subscription();
+        $subscription->uuid = Uuid::uuid4()->toString();
+        $subscription->userRelation()->associate($user);
+        $subscription->subscriptionAbleRelation()->associate($this);
+
+        return $this->subscriptionsRelation()->save($subscription);
+    }
 }

app/Concerns/ReceivesReplies.php

@@ -3,7 +3,10 @@
 namespace App\Concerns;
 
 use App\Models\Reply;
+use App\Models\User;
+use Illuminate\Database\Eloquent\Relations\HasManyThrough;
 use Illuminate\Database\Eloquent\Relations\MorphMany;
+use Illuminate\Database\Eloquent\Relations\Relation;
 
 trait ReceivesReplies
 {
@@ -15,6 +18,21 @@ public function replies()
         return $this->repliesRelation;
     }
 
+    public function replyAuthors(): HasManyThrough
+    {
+        return $this->hasManyThrough(
+            User::class,
+            Reply::class,
+            'replyable_id',
+            'id',
+            'id',
+            'author_id',
+        )->where(
+            'replyable_type',
+            array_search(static::class, Relation::morphMap()),
+        );
+    }
+
     /**
      * @return \Illuminate\Database\Eloquent\Collection
      */

app/Events/ThreadWasCreated.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\Events;
+
+use App\Models\Thread;
+use Illuminate\Queue\SerializesModels;
+
+final class ThreadWasCreated
+{
+    use SerializesModels;
+
+    public function __construct(
+        public Thread $thread
+    ) {
+    }
+}

app/Http/Livewire/Editor.php

@@ -2,6 +2,9 @@
 
 namespace App\Http\Livewire;
 
+use App\Models\User;
+use Illuminate\Support\Collection;
+use Illuminate\Support\Str;
 use Livewire\Component;
 
 class Editor extends Component
@@ -20,19 +23,55 @@ class Editor extends Component
 
     public $buttonIcon;
 
+    public $hasMentions = false;
+
+    public $users;
+
+    public $participants;
+
+    public function mount($participants = null)
+    {
+        $this->users = collect();
+        $this->participants = $participants ?: collect();
+    }
+
     public function render()
     {
         $this->body = old('body', $this->body);
 
         return view('livewire.editor');
     }
 
-    public function getPreviewProperty()
+    public function getUsers($query): Collection
+    {
+        if (! $this->hasMentions) {
+            return $this->users;
+        }
+
+        if (! $query) {
+            return $this->users = $this->participants;
+        }
+
+        $query = Str::after($query, '@');
+        $users = User::where('username', 'like', "{$query}%")->take(5)->get();
+
+        if ($this->participants->isNotEmpty()) {
+            $users = $this->participants->filter(function ($participant) use ($query) {
+                return Str::startsWith($participant['username'], $query);
+            })
+                ->merge($users)
+                ->unique('id');
+        }
+
+        return $this->users = $users;
+    }
+
+    public function getPreviewProperty(): string
     {
         return replace_links(md_to_html($this->body ?: ''));
     }
 
-    public function preview()
+    public function preview(): void
     {
         $this->emit('previewRequested');
     }

app/Jobs/CreateThread.php

@@ -2,6 +2,7 @@
 
 namespace App\Jobs;
 
+use App\Events\ThreadWasCreated;
 use App\Http\Requests\ThreadRequest;
 use App\Models\Subscription;
 use App\Models\Thread;
@@ -48,6 +49,8 @@ public function handle(): Thread
 
         $thread->subscriptionsRelation()->save($subscription);
 
+        event(new ThreadWasCreated($thread));
+
         return $thread;
     }
 }

app/Listeners/NotifyUsersMentionedInReply.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Listeners;
+
+use App\Events\ReplyWasCreated;
+use App\Notifications\MentionNotification;
+
+final class NotifyUsersMentionedInReply
+{
+    public function handle(ReplyWasCreated $event): void
+    {
+        $event->reply->getMentionedUsers()->each(function ($user) use ($event) {
+            $user->notify(new MentionNotification($event->reply));
+        });
+    }
+}

app/Listeners/NotifyUsersMentionedInThread.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Listeners;
+
+use App\Events\ThreadWasCreated;
+use App\Notifications\MentionNotification;
+
+final class NotifyUsersMentionedInThread
+{
+    public function handle(ThreadWasCreated $event): void
+    {
+        $event->thread->getMentionedUsers()->each(function ($user) use ($event) {
+            $user->notify(new MentionNotification($event->thread));
+        });
+    }
+}

app/Listeners/SubscribeUsersMentionedInReply.php

@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Listeners;
+
+use App\Events\ReplyWasCreated;
+use App\Models\Thread;
+
+final class SubscribeUsersMentionedInReply
+{
+    public function handle(ReplyWasCreated $event): void
+    {
+        $event->reply->getMentionedUsers()->each(function ($user) use ($event) {
+            $replyAble = $event->reply->mentionedIn();
+
+            if ($replyAble instanceof Thread && ! $replyAble->hasSubscriber($user)) {
+                $replyAble->subscribe($user);
+            }
+        });
+    }
+}

app/Listeners/SubscribeUsersMentionedInThread.php

@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Listeners;
+
+use App\Events\ThreadWasCreated;
+
+final class SubscribeUsersMentionedInThread
+{
+    public function handle(ThreadWasCreated $event): void
+    {
+        $event->thread->getMentionedUsers()->each(function ($user) use ($event) {
+            if (! $event->thread->hasSubscriber($user)) {
+                $event->thread->subscribe($user);
+            }
+        });
+    }
+}

app/Mail/MentionEmail.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace App\Mail;
+
+use App\Models\MentionAble;
+use App\Models\User;
+use Illuminate\Mail\Mailable;
+
+final class MentionEmail extends Mailable
+{
+    public function __construct(
+        public MentionAble $mentionAble,
+        public User $receiver
+    ) {
+    }
+
+    public function build()
+    {
+        return $this->subject("Mentioned: {$this->mentionAble->mentionedIn()->subject()}")
+            ->markdown('emails.mention');
+    }
+}

app/Models/MentionAble.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Support\Collection;
+
+interface MentionAble
+{
+    public function body(): string;
+
+    public function excerpt(): string;
+
+    public function author(): User;
+
+    public function mentionedIn(): ReplyAble;
+
+    public function getMentionedUsers(): Collection;
+}

app/Models/Reply.php

@@ -4,6 +4,7 @@
 
 use App\Concerns\HasAuthor;
 use App\Concerns\HasLikes;
+use App\Concerns\HasMentions;
 use App\Concerns\HasTimestamps;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
@@ -13,11 +14,12 @@
 use Illuminate\Database\Eloquent\Relations\MorphTo;
 use Illuminate\Support\Str;
 
-final class Reply extends Model
+final class Reply extends Model implements MentionAble
 {
-    use HasFactory;
     use HasAuthor;
+    use HasFactory;
     use HasLikes;
+    use HasMentions;
     use HasTimestamps;
 
     const TABLE = 'replies';

app/Models/Thread.php

@@ -4,6 +4,7 @@
 
 use App\Concerns\HasAuthor;
 use App\Concerns\HasLikes;
+use App\Concerns\HasMentions;
 use App\Concerns\HasSlug;
 use App\Concerns\HasTags;
 use App\Concerns\HasTimestamps;
@@ -26,11 +27,12 @@
 use Spatie\Feed\Feedable;
 use Spatie\Feed\FeedItem;
 
-final class Thread extends Model implements Feedable, ReplyAble, SubscriptionAble
+final class Thread extends Model implements Feedable, ReplyAble, SubscriptionAble, MentionAble
 {
-    use HasFactory;
     use HasAuthor;
+    use HasFactory;
     use HasLikes;
+    use HasMentions;
     use HasSlug;
     use HasTags;
     use HasTimestamps;
@@ -340,4 +342,12 @@ public function scopeUnlocked(Builder $query): Builder
     {
         return $query->whereNull('locked_at');
     }
+
+    public function participants(): SupportCollection
+    {
+        return $this->replyAuthors()
+            ->get()
+            ->prepend($this->author())
+            ->unique();
+    }
 }