//! OS registration adapter for the shared safe-boundary signal controller.
use signal_hook::consts::signal::{SIGINT, SIGTERM};
use signal_hook::SigId;
use crate::app::AppError;
pub(crate) use hexwork_game::signals::SignalController;

pub(crate) struct InstalledSignals {
    controller: SignalController,
    registrations: Vec<SigId>,
}

impl InstalledSignals {
    pub(crate) fn install() -> Result<Self, AppError> {
        let controller = SignalController::default();
        let mut registrations = Vec::with_capacity(2);
        for signal in [SIGINT, SIGTERM] {
            match signal_hook::flag::register(signal, controller.pending_flag()) {
                Ok(id) => registrations.push(id),
                Err(error) => {
                    for id in registrations { signal_hook::low_level::unregister(id); }
                    return Err(AppError::io("signal-install", format!("failed to register signal {signal}: {error}")));
                }
            }
        }
        Ok(Self { controller, registrations })
    }
    pub(crate) fn controller(&self) -> SignalController { self.controller.clone() }
}
impl Drop for InstalledSignals {
    fn drop(&mut self) {
        for id in self.registrations.drain(..) { signal_hook::low_level::unregister(id); }
    }
}