Simplified and aligned handling of mixed entity endpoints

Fixes #4444

app/Activity/Controllers/WatchController.php

@@ -3,25 +3,23 @@
 namespace BookStack\Activity\Controllers;
 
 use BookStack\Activity\Tools\UserEntityWatchOptions;
-use BookStack\App\Model;
-use BookStack\Entities\Models\Entity;
+use BookStack\Entities\Tools\MixedEntityRequestHelper;
 use BookStack\Http\Controller;
-use Exception;
 use Illuminate\Http\Request;
-use Illuminate\Validation\ValidationException;
 
 class WatchController extends Controller
 {
-    public function update(Request $request)
+    public function update(Request $request, MixedEntityRequestHelper $entityHelper)
     {
         $this->checkPermission('receive-notifications');
         $this->preventGuestAccess();
 
         $requestData = $this->validate($request, [
             'level' => ['required', 'string'],
+            ...$entityHelper->validationRules()
         ]);
 
-        $watchable = $this->getValidatedModelFromRequest($request);
+        $watchable = $entityHelper->getVisibleEntityFromRequestData($requestData);
         $watchOptions = new UserEntityWatchOptions(user(), $watchable);
         $watchOptions->updateLevelByName($requestData['level']);
 
@@ -29,37 +27,4 @@ class WatchController extends Controller
 
         return redirect()->back();
     }
-
-    /**
-     * @throws ValidationException
-     * @throws Exception
-     */
-    protected function getValidatedModelFromRequest(Request $request): Entity
-    {
-        $modelInfo = $this->validate($request, [
-            'type' => ['required', 'string'],
-            'id'   => ['required', 'integer'],
-        ]);
-
-        if (!class_exists($modelInfo['type'])) {
-            throw new Exception('Model not found');
-        }
-
-        /** @var Model $model */
-        $model = new $modelInfo['type']();
-        if (!$model instanceof Entity) {
-            throw new Exception('Model not an entity');
-        }
-
-        $modelInstance = $model->newQuery()
-            ->where('id', '=', $modelInfo['id'])
-            ->first(['id', 'name', 'owned_by']);
-
-        $inaccessibleEntity = ($modelInstance instanceof Entity && !userCan('view', $modelInstance));
-        if (is_null($modelInstance) || $inaccessibleEntity) {
-            throw new Exception('Model instance not found');
-        }
-
-        return $modelInstance;
-    }
 }