"""
Utility functions for the LightRAG API.
"""

from typing import Optional
from fastapi import HTTPException, Security
from fastapi.security import APIKeyHeader
from starlette.status import HTTP_403_FORBIDDEN

def get_api_key_dependency(api_key: Optional[str]):
    """
    Create an API key dependency for route protection.

    Args:
        api_key (Optional[str]): The API key to validate against.
                                If None, no authentication is required.

    Returns:
        Callable: A dependency function that validates the API key.
    """
    if not api_key:
        # If no API key is configured, return a dummy dependency that always succeeds
        async def no_auth():
            return None

        return no_auth

    # If API key is configured, use proper authentication
    api_key_header = APIKeyHeader(name="X-API-Key", auto_error=False)

    async def api_key_auth(
        api_key_header_value: Optional[str] = Security(api_key_header),
    ):
        if not api_key_header_value:
            raise HTTPException(
                status_code=HTTP_403_FORBIDDEN, detail="API Key required"
            )
        if api_key_header_value != api_key:
            raise HTTPException(
                status_code=HTTP_403_FORBIDDEN, detail="Invalid API Key"
            )
        return api_key_header_value

    return api_key_auth