from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
import jwt
from jwt.exceptions import InvalidTokenError
from src.config import auth_settings
from .service import AuthService

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/auth/login")
auth_service = AuthService()

def get_current_user(token: str = Depends(oauth2_scheme)) -> str:
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, auth_settings.secret_key, algorithms=[auth_settings.algorithm])
        user_id = payload.get("sub")
        if user_id is None:
            raise credentials_exception
    except InvalidTokenError:
        raise credentials_exception
    
    user = auth_service.get_user_by_id(user_id)
    if user is None:
        raise credentials_exception
    return user_id