from typing import Annotated, Any
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import JWTError, jwt

from app.core.security import SECRET_KEY, ALGORITHM
from app.db.session import get_db
from app.crud import get_user_by_username
from app.schemas import TokenData

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="api/v1/auth/login")

def get_current_user(token: Annotated[str, Depends(oauth2_scheme)], db: Any = Depends(get_db)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
    except JWTError:
        raise credentials_exception
        
    user = get_user_by_username(db, username=token_data.username)
    if user is None:
        raise credentials_exception
    return user