I am a Russian citizen and at the end of 2019 I came to California for a traineeship.
I have income in both Russia and the United States (California).
From the point of view of US federal tax law, I'm a Non-Resident Alien (all days of the first 2 years of traineeship excluded from "days of presence" counting).
California state tax laws are getting more complicated. I can't figure out when I'm gonna be a California resident and have to declare my income from outside.
How do I determine my residency status for tax purposes for California?
What regulations should I rely on?