from typing import Optional
from sqlalchemy.ext.asyncio import AsyncSession
from app.crud import user as crud_user
from app.core.security import verify_password, create_access_token, create_refresh_token, decode_token
from app.schemas.user import UserCreate
from app.schemas.token import Token
from datetime import timedelta


class AuthService:
    async def authenticate(
        self,
        db: AsyncSession,
        email: str,
        password: str
    ) -> Optional[Token]:
        """Аутентификация пользователя"""
        db_user = await crud_user.get_by_email(db, email)
        if not db_user:
            return None
        
        if not verify_password(password, db_user.hashed_password):
            return None
        
        access_token = create_access_token(
            data={"sub": db_user.id, "email": db_user.email}
        )
        refresh_token = create_refresh_token(
            data={"sub": db_user.id, "email": db_user.email}
        )
        
        return Token(
            access_token=access_token,
            refresh_token=refresh_token,
            token_type="bearer"
        )
    
    async def register(
        self,
        db: AsyncSession,
        user_in: UserCreate
    ):
        """Регистрация нового пользователя"""
        # Проверка существования пользователя
        existing_user = await crud_user.get_by_email(db, user_in.email)
        if existing_user:
            raise ValueError("User with this email already exists")
        
        from app.core.security import get_password_hash
        hashed_password = get_password_hash(user_in.password)
        
        db_user = await crud_user.create(db, user_in, hashed_password)
        return db_user
    
    def verify_token(self, token: str) -> Optional[dict]:
        """Проверка токена"""
        payload = decode_token(token)
        if payload and payload.get("type") == "access":
            return payload
        return None
    
    def refresh_access_token(self, refresh_token: str) -> Optional[str]:
        """Обновление access token"""
        payload = decode_token(refresh_token)
        if payload and payload.get("type") == "refresh":
            return create_access_token(
                data={"sub": payload.get("sub"), "email": payload.get("email")}
            )
        return None


auth_service = AuthService()