import hmac

from cryptography.fernet import Fernet
from fastapi import Depends, HTTPException
from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer

from app.config import get_settings

_bearer = HTTPBearer(auto_error=False)


def _fernet() -> Fernet:
    key = get_settings().secret_key
    if not key:
        raise RuntimeError("SECRET_KEY не задан (ключ Fernet)")
    return Fernet(key.encode())


def encrypt(value: str) -> str:
    return _fernet().encrypt(value.encode()).decode()


def decrypt(token: str) -> str:
    return _fernet().decrypt(token.encode()).decode()


def check_admin(user: str, password: str) -> bool:
    s = get_settings()
    ok_user = hmac.compare_digest(user.encode(), s.admin_user.encode())
    ok_pass = hmac.compare_digest(password.encode(), s.admin_password.encode())
    return ok_user and ok_pass


def require_api_token(cred: HTTPAuthorizationCredentials | None = Depends(_bearer)) -> None:
    expected = get_settings().api_token
    if cred is None or not hmac.compare_digest(cred.credentials.encode(), expected.encode()):
        raise HTTPException(status_code=401, detail="Invalid or missing API token")