"""
Authentication Dependency for FastAPI
Provides dependency to get current authenticated user from JWT token
"""

from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from typing import Optional
import sys
import os

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from services.auth import auth_service

security = HTTPBearer()


async def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security)
) -> str:
    """
    Dependency to get the current authenticated user from JWT token.
    
    Raises HTTPException if token is invalid or missing.
    """
    token = credentials.credentials
    username = auth_service.verify_token(token)
    
    if username is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid authentication credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    return username


async def get_current_user_optional(
    credentials: Optional[HTTPAuthorizationCredentials] = Depends(HTTPBearer(auto_error=False))
) -> Optional[str]:
    """
    Optional dependency to get current user if token is provided.
    Returns None if no token or invalid token.
    """
    if credentials is None:
        return None
    
    token = credentials.credentials
    username = auth_service.verify_token(token)
    return username