//! Tracks the last-activity timestamp; the GTK timer queries this each tick
//! to decide whether 60s of idle has elapsed.

use std::time::{Duration, Instant};

pub(crate) struct WatchdogState {
    last_activity: Instant,
    timeout: Duration,
}

impl WatchdogState {
    pub fn new(timeout: Duration) -> Self {
        Self {
            last_activity: Instant::now(),
            timeout,
        }
    }

    pub fn poke(&mut self) {
        self.last_activity = Instant::now();
    }

    /// True iff `timeout` has passed since the last poke. Once expired,
    /// stays expired until the caller drops + recreates.
    pub fn expired(&self) -> bool {
        self.last_activity.elapsed() >= self.timeout
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn fresh_state_is_not_expired() {
        let w = WatchdogState::new(Duration::from_secs(60));
        assert!(!w.expired());
    }

    #[test]
    fn zero_timeout_is_immediately_expired() {
        let w = WatchdogState::new(Duration::from_millis(0));
        std::thread::sleep(Duration::from_millis(2));
        assert!(w.expired());
    }

    #[test]
    fn poke_resets_the_clock() {
        let mut w = WatchdogState::new(Duration::from_millis(100));
        std::thread::sleep(Duration::from_millis(150));
        assert!(w.expired());
        w.poke();
        assert!(!w.expired());
    }
}