//! Staleness detection for lesson cache entries.

use std::time::{SystemTime, UNIX_EPOCH};

/// How long (in seconds) before a lesson is considered stale.
const STALE_THRESHOLD_SECS: u64 = 86400 * 7; // 7 days

/// Check whether a lesson timestamp is stale.
pub fn is_stale(updated_at: i64) -> bool {
    let now = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .unwrap_or_default()
        .as_secs() as i64;
    now.saturating_sub(updated_at) > STALE_THRESHOLD_SECS as i64
}