add function to check if to be deleted user has loans

src/logic/database.py

@@ -273,7 +273,18 @@ class Database:
         if len(result) == 0:
             log.info(f"Deleting {len(result)} inactive users")
             for user in result:
-                self.deleteUser(user)
+                hasLoans = self.hasLoans(user[0])
+                if not hasLoans:
+                    self.deleteUser(user)
+    
+    def hasLoans(self, userid)->bool:
+        query = f"SELECT * FROM loans WHERE user_id = '{userid}' AND returned = 0"
+        conn = self.connect()
+        cursor = conn.cursor()
+        cursor.execute(query)
+        result = cursor.fetchall()  
+        self.close_connection(conn)
+        return False if len(result) == 0 else True
     
     def deleteUser(self, userid):
         log.debug(f"Deleting User {userid}")