from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import jwt, JWTError
from sqlalchemy.orm import Session

from app.core.config import settings
from app.db.session import get_db
from app.models.user import User
from app.schemas.token import TokenPayload

# OAuth2 scheme for token authentication
oauth2_scheme = OAuth2PasswordBearer(tokenUrl=f"{settings.API_V1_PREFIX}/auth/login")


def get_current_user(
    db: Session = Depends(get_db),
    token: str = Depends(oauth2_scheme),
) -> User:
    """
    Get the current user based on the provided JWT token.

    Args:
        db: Database session.
        token: JWT token from the Authorization header.

    Returns:
        The current authenticated user.

    Raises:
        HTTPException: If the token is invalid or the user is not found.
    """
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )

    try:
        # Decode JWT token
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
        )
        token_data = TokenPayload(**payload)

        if token_data.sub is None:
            raise credentials_exception

    except JWTError:
        raise credentials_exception

    # Get the user from the database
    user = db.query(User).filter(User.id == token_data.sub).first()

    if user is None:
        raise credentials_exception

    if not user.is_active:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Inactive user",
        )

    return user


def get_current_active_superuser(
    current_user: User = Depends(get_current_user),
) -> User:
    """
    Get the current user and verify they are a superuser.

    Args:
        current_user: Current authenticated user.

    Returns:
        The current authenticated superuser.

    Raises:
        HTTPException: If the user is not a superuser.
    """
    if not current_user.is_superuser:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Not enough permissions",
        )

    return current_user