"""
Authentication middleware for JWT token verification.
"""
from fastapi import Depends, HTTPException, status, Request
from fastapi.security import HTTPBearer
from fastapi.security.http import HTTPAuthorizationCredentials
from sqlmodel import Session
from src.core.security import decode_access_token
from src.db.session import get_session
from src.services.user_service import UserService
from src.models.user import User

security = HTTPBearer(auto_error=False)


def get_current_user(
    request: Request,
    credentials: HTTPAuthorizationCredentials = Depends(security),
    session: Session = Depends(get_session)
) -> User:
    """
    Dependency to get current authenticated user from JWT token.

    Args:
        request: FastAPI request object
        credentials: HTTP Bearer credentials containing JWT token
        session: Database session

    Returns:
        User: Authenticated user

    Raises:
        HTTPException: If token is invalid or user not found
    """
    # Skip authentication for OPTIONS requests (CORS preflight)
    if request.method == "OPTIONS":
        return None
    
    if credentials is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Not authenticated",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    token = credentials.credentials
    payload = decode_access_token(token)

    if payload is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid authentication token",
            headers={"WWW-Authenticate": "Bearer"},
        )

    user_id: int = payload.get("sub")
    if user_id is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid authentication token",
            headers={"WWW-Authenticate": "Bearer"},
        )

    user = UserService.get_user_by_id(session, user_id)
    if user is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="User not found",
            headers={"WWW-Authenticate": "Bearer"},
        )

    if not user.is_active:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Inactive user"
        )

    return user