Fix getactivity first and last

app/Http/Controllers/ActivityController.php

@@ -151,7 +151,10 @@ class ActivityController extends Controller
 	}
 
 	public function getActivityFirst($parentId){
-		$activity = Activity::where('parent_id', $parentId)->orderByRaw('start_date ASC')->first(); 
+		$activity = Activity::where('parent_id', $parentId)->orderByRaw('actual_start ASC')->first(); 
+		if (!isset($activity)) {
+			return null;
+		}
 		if($activity->type_activity == "task"){ 
 			// Log::info("activity ", [$activity]);
 			return $activity->actual_start;
@@ -162,7 +165,10 @@ class ActivityController extends Controller
 	}
 
 	public function getActivityLast($parentId){
-		$activity = Activity::where('parent_id', $parentId)->orderByRaw('start_date DESC')->first(); 
+		$activity = Activity::where('parent_id', $parentId)->orderByRaw('actual_end DESC')->first(); 
+		if (!isset($activity)) {
+			return null;
+		}
 		if($activity->type_activity == "task"){ 
 			// Log::info("activity ", [$activity]);
 			return $activity->actual_end;