app/middleware/auth.py

from typing import Optional
from fastapi import Request, HTTPException, status, Depends
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from jose import JWTError, jwt

from app.config.settings import settings
from app.database.connection import get_db
from app.database.models import User

security = HTTPBearer()


def get_current_user_optional(
    credentials: Optional[HTTPAuthorizationCredentials] = Depends(HTTPBearer(auto_error=False))
) -> Optional[User]:
    """
    Get current user from JWT token (optional - doesn't raise error if no token).
    
    Args:
        credentials: Optional HTTP authorization credentials
        
    Returns:
        User object if authenticated, None otherwise
    """
    if not credentials:
        return None
        
    try:
        token = credentials.credentials
        payload = jwt.decode(
            token,
            settings.secret_key,
            algorithms=[settings.algorithm]
        )
        user_id: str = payload.get("sub")
        
        if user_id is None:
            return None
            
        # Get user from database
        db = next(get_db())
        user = db.query(User).filter(User.id == user_id).first()
        return user
        
    except JWTError:
        return None


def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security)
) -> User:
    """
    Get current user from JWT token (required - raises error if no valid token).
    
    Args:
        credentials: HTTP authorization credentials
        
    Returns:
        User object
        
    Raises:
        HTTPException: If token is invalid or user not found
    """
    try:
        token = credentials.credentials
        payload = jwt.decode(
            token,
            settings.secret_key,
            algorithms=[settings.algorithm]
        )
        user_id: str = payload.get("sub")
        
        if user_id is None:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="Could not validate credentials"
            )
            
        # Get user from database
        db = next(get_db())
        user = db.query(User).filter(User.id == user_id).first()
        
        if user is None:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="User not found"
            )
            
        return user
        
    except JWTError:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Could not validate credentials"
        )