Formatted following CakePHP conventions rules (on CakePHP CodeSniffer https://github.com/cakephp/cakephp-codesniffer)
Split the logic between Paypal RestFul API and Classic API (next step create different files with the logic)
Create method to interact with Paypal OAuth authentication
Create methods to interact with credit cards and the Paypal RestFul API (HATEOAS, store, payment)