Hello Sir, I can able to help you to do your task for Oath2 login , as I've worked this in various clienside applications , so I can able to complete this asap, please contact me further,
> Web Applications using PHP + MySQLi + API + jQuery
> Restful Web services: REST, SOAP
> Payment Gateway : Ccavenue, EBS, Paypal, Bitcoin
> Design Pattern : Bootstrap 3+
> CMS: Wordpress, Joomla