I am a PHP programmer but I have never developed anything yet for drupal. I have used Drupal as a CMS before but I didn't do any custom code since everything I needed at before can be accomplished with existing modules.
Now, with my new project, I have an existing single-page app using a PHP RESTful API and AngularJS on the frontend. I want it to be integrated with a Drupal CMS.
I am aware of the following possible ways to do this:
Rewrite my existing code into a Drupal module - There is very little possibility that this app will be re-used. Furthermore, it is more likely that this app will be used stand-alone without Drupal. I also don't think I have the time to learn how to write a Drupal module.
Keep the backend API as it is now and write the frontend as a Drupal page. - This will put my frontend code inside the Drupal database and NOT in the filesytem anymore so I can't version control the frontend code.
I am not happy with the above two choices and I believe that there is a better way to do achieve what I want.
Additional background of my custom app:
I created this app as a way for me to learn more about single-page applications. It is already currently functioning well as a standalone app. The app basically collects information from several users and collates all those information to be displayed on an HTML table.
I am sure there is also a Drupal way of doing the things that my Angular app does (something like a custom node type with fields coming from the input of different users) but I would like to use my existing code if that makes it easier.