from typing import Optional
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.user import User
from app.services.user import UserService
from app.core.security import create_access_token


class AuthService:
    def __init__(self, db: AsyncSession):
        self.db = db
        self.user_service = UserService(db)

    async def login(self, username: str, password: str) -> Optional[dict]:
        user = await self.user_service.authenticate(username, password)
        if not user:
            return None

        access_token = create_access_token(data={"sub": str(user.id)})
        return {
            "access_token": access_token,
            "token_type": "bearer",
            "user": user
        }

    async def register(self, data: dict) -> Optional[dict]:
        existing_user = await self.user_service.get_user_by_username(data["username"])
        if existing_user:
            return None

        user = await self.user_service.create_user(data)
        access_token = create_access_token(data={"sub": str(user.id)})
        return {
            "access_token": access_token,
            "token_type": "bearer",
            "user": user
        }