"""Authentication service for business logic."""
from typing import Optional
from sqlalchemy.orm import Session
from backend.models.user import User
from backend import auth
from backend.schemas.user import UserCreate


class AuthService:
    """Service for authentication operations."""

    @staticmethod
    def register_user(db: Session, user_data: UserCreate) -> User:
        """Register a new user."""
        db_user = db.query(User).filter(
            User.username == user_data.username
        ).first()
        if db_user:
            raise ValueError("Username already registered")
        
        hashed_password = auth.get_password_hash(user_data.password)
        new_user = models.User(
            username=user_data.username,
            hashed_password=hashed_password
        )
        db.add(new_user)
        db.commit()
        db.refresh(new_user)
        return new_user

    @staticmethod
    def authenticate_user(db: Session, username: str, password: str) -> Optional[User]:
        """Authenticate a user with username and password."""
        user = db.query(User).filter(
            User.username == username
        ).first()
        if not user or not auth.verify_password(password, user.hashed_password):
            return None
        return user

    @staticmethod
    def create_access_token(username: str) -> str:
        """Create a JWT access token for a user."""
        from datetime import timedelta
        from backend.core.config import settings
        
        access_token_expires = timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
        access_token = auth.create_access_token(
            data={"sub": username},
            expires_delta=access_token_expires
        )
        return access_token