I think you already gave the answer to your self, but didn't realize. You have two options:
1.) Leave this mess behind you and quit - and miss an opportunity to learn a lot about code, yourself, teamwork and solving real world problems
2.) Work together with your team and solve problems, that probably will improve your skills more than anything in your future
I recommend you to give 2.) at least 6 months, before your quit.
What I would recommend:
- Create a git repository (I would not init it on the production server, but copy the code over to your machine, init, experiment a bit, and if you found a reliable way, repeat this process on the server)
- For the first weeks, continue developing on the server with one main branch, but at least push it to a central repository, so that you have a kind of VCS
- Setup a dev system, that points to a cloned (maybe stripped down) prod database, where you can test things
- Add composer in dev and see, if you manage to migrate this to production
- As you said, you already have an API, that is called via curl. That might be the way out of your mess. Create a new API namespace / directory in the old code base, that is fully under version control, uses composer and as little of the OLD mess of code as possible (you won't get out of this with a full rewrite). Write unit tests, wherever possible.
- I recommend to use jsonrpc in your situation, because it is more flexible than CRUD / REST, but this is up to you
- Get SonarQube up and running for the new API and manage your code quality improvement
- New features go to the new API, if possible
- Start to move old features to the new API, create branches and deploy only ONE folder from dev to prod: the api directory
- The database mess is a problem, that you should not solve too early...
1.) Leave this mess behind you and quit - and miss an opportunity to learn a lot about code, yourself, teamwork and solving real world problems
2.) Work together with your team and solve problems, that probably will improve your skills more than anything in your future
I recommend you to give 2.) at least 6 months, before your quit.
What I would recommend:
- Create a git repository (I would not init it on the production server, but copy the code over to your machine, init, experiment a bit, and if you found a reliable way, repeat this process on the server)
- For the first weeks, continue developing on the server with one main branch, but at least push it to a central repository, so that you have a kind of VCS
- Setup a dev system, that points to a cloned (maybe stripped down) prod database, where you can test things
- Add composer in dev and see, if you manage to migrate this to production
- As you said, you already have an API, that is called via curl. That might be the way out of your mess. Create a new API namespace / directory in the old code base, that is fully under version control, uses composer and as little of the OLD mess of code as possible (you won't get out of this with a full rewrite). Write unit tests, wherever possible.
- I recommend to use jsonrpc in your situation, because it is more flexible than CRUD / REST, but this is up to you
- Get SonarQube up and running for the new API and manage your code quality improvement
- New features go to the new API, if possible
- Start to move old features to the new API, create branches and deploy only ONE folder from dev to prod: the api directory
- The database mess is a problem, that you should not solve too early...
This should take roughly a year. Have fun ;)