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

from app.db.session import get_db
from app.core.config import settings
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_STR}/users/login"
)


def get_current_user(
    db: Session = Depends(get_db), token: str = Depends(oauth2_scheme)
) -> User:
    """
    Get the current authenticated user.
    
    Args:
        db: Database session
        token: JWT token
        
    Returns:
        User object
        
    Raises:
        HTTPException: If authentication fails
    """
    try:
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
        )
        token_data = TokenPayload(**payload)
    except (JWTError, ValidationError):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Could not validate credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    user = db.query(User).filter(User.id == token_data.sub).first()
    
    if not user:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="User not found"
        )
    
    if not user.is_active:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Inactive user"
        )
    
    return user


def get_current_active_user(
    current_user: User = Depends(get_current_user),
) -> User:
    """
    Get the current active user.
    
    Args:
        current_user: Current user
        
    Returns:
        User object
        
    Raises:
        HTTPException: If user is inactive
    """
    if not current_user.is_active:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Inactive user"
        )
    
    return current_user


def get_current_active_superuser(
    current_user: User = Depends(get_current_user),
) -> User:
    """
    Get the current active superuser.
    
    Args:
        current_user: Current user
        
    Returns:
        User object
        
    Raises:
        HTTPException: If user is not a superuser
    """
    if not current_user.is_superuser:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="The user doesn't have enough privileges"
        )
    
    return current_user