By "class A" I assume you mean "FAA First Class Medical"?

You'll probably need to be pay for some evaluations and provide those results to the AME/FAA. The AME may be able to walk you through that if he's good. Alternatively you might be able to find an AME who is known for handling such issues. If time is urgent, consider paying an aviation medical consultant such as AMAS... they can at the very least answer all your questions and explain the process and timeline.

If it's not a current problem, you should get cleared.

I assume it will be important that you do not drink at all any more. Also you need to never have any kind of documented alcohol issue in the future... should be easy if you just don't touch the stuff.

Others may be able to provide more details and timelines.