"""Shared FastAPI dependencies for accessing and protecting UVM services."""

from __future__ import annotations

import hmac
from typing import cast

from fastapi import Header, HTTPException, Request, status

from ..app import Application


def get_application(request: Request) -> Application:
    return cast(Application, request.app.state.uvm_application)


def get_authorized_application(
    request: Request,
    x_uvm_token: str | None = Header(default=None),
) -> Application:
    application = get_application(request)
    expected_token = application.settings.api_token
    if not expected_token:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="UVM_API_TOKEN is not configured",
        )
    if not hmac.compare_digest(x_uvm_token or "", expected_token):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="missing or invalid X-UVM-Token",
        )
    return application