from typing import List, Dict, Optional, Set, Tuple
from pydantic import BaseModel


class User(BaseModel):
    username: str
    email: Optional[str] = None
    youtube_credentials: Optional[Dict] = None

class UserDatabase:
    """
    In-memory user database. In a production app, 
    replace with a proper database like SQLAlchemy
    """
    users = {}

    @classmethod
    def create_user(cls, username: str, credentials: Dict):
        user = User(username=username, youtube_credentials=credentials)
        cls.users[username] = user
        return user

    @classmethod
    def get_user(cls, username: str):
        return cls.users.get(username)