messages implemented

app/Observers/ArtworkCommentObserver.php

@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Observers;
+
+use App\Models\ArtworkComment;
+use App\Services\UserStatsService;
+use Illuminate\Support\Facades\DB;
+
+/**
+ * Updates the artwork creator's comments_received_count and last_active_at
+ * when a comment is created or (soft-)deleted.
+ */
+class ArtworkCommentObserver
+{
+    public function __construct(
+        private readonly UserStatsService $userStats,
+    ) {}
+
+    public function created(ArtworkComment $comment): void
+    {
+        $creatorId = $this->creatorId($comment->artwork_id);
+        if ($creatorId) {
+            $this->userStats->incrementCommentsReceived($creatorId);
+        }
+
+        // The commenter is "active"
+        $this->userStats->ensureRow($comment->user_id);
+        $this->userStats->setLastActiveAt($comment->user_id);
+    }
+
+    /** Soft delete. */
+    public function deleted(ArtworkComment $comment): void
+    {
+        $creatorId = $this->creatorId($comment->artwork_id);
+        if ($creatorId) {
+            $this->userStats->decrementCommentsReceived($creatorId);
+        }
+    }
+
+    /** Hard delete after soft delete — already decremented; nothing to do. */
+    public function forceDeleted(ArtworkComment $comment): void
+    {
+        // Only decrement if the comment was NOT already soft-deleted
+        // (to avoid double-decrement).
+        if ($comment->deleted_at === null) {
+            $creatorId = $this->creatorId($comment->artwork_id);
+            if ($creatorId) {
+                $this->userStats->decrementCommentsReceived($creatorId);
+            }
+        }
+    }
+
+    private function creatorId(int $artworkId): ?int
+    {
+        $id = DB::table('artworks')
+            ->where('id', $artworkId)
+            ->value('user_id');
+
+        return $id !== null ? (int) $id : null;
+    }
+}