refactor(model): Track model persistence state

src/Libs/Model.php

@@ -43,6 +43,10 @@ class Model
      */
     protected static array $dbForceSave = [];
 
+    /**
+     * @var bool Attribute that persis if is current model is saved into the database
+     */
+    protected bool $dbIsSaved = false;
 
     /**
      * @var string The database table name.
@@ -306,6 +310,8 @@ class Model
             }
         }
 
+        $instance->markAsSaved();
+
         return $instance;
     }
 
@@ -466,23 +472,34 @@ class Model
 
         $pk = static::$dbPrimaryKey;
         $this->$pk = $db->lastInsertId();
+        $this->markAsSaved();
     }
 
     /**
      * Checks if the object to be saved is new or not, and based on the result,
      * calls `update` to update an existing row or `add` to insert a new row.
+     *
      * @return void
      */
     public function save(): void
     {
-        $pk = static::$dbPrimaryKey;
-        if (isset($this->$pk)) {
+        if ($this->dbIsSaved) {
             $this->update();
         } else {
             $this->add();
         }
     }
 
+    /**
+     * Mark the current instance as already saved
+     *
+     * @return void
+     */
+    public function markAsSaved(): void
+    {
+        $this->dbIsSaved = true;
+    }
+
     /**
      * Deletes the current object from the database.
      * @return void
@@ -495,6 +512,7 @@ class Model
 
         static::$dbQueryVariables[":$pk"] = $this->$pk;
         static::query($sql);
+        $this->dbIsSaved = false;
     }
 
     /**