use std::time::{SystemTime, UNIX_EPOCH};
pub fn unix_seconds() -> i64 {
    SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map(|elapsed| elapsed.as_secs() as i64)
        .unwrap_or_default()
}
pub fn unix_millis() -> i64 {
    SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map(|elapsed| elapsed.as_millis() as i64)
        .unwrap_or_default()
}
pub fn format_utc(seconds: i64) -> String {
    let days_since_epoch = seconds.div_euclid(86_400);
    let seconds_of_day = seconds.rem_euclid(86_400);
    let (year, month, day) = civil_from_days(days_since_epoch);
    format!(
        "{year:04}-{month:02}-{day:02}T{:02}:{:02}:{:02}Z",
        seconds_of_day / 3_600,
        (seconds_of_day % 3_600) / 60,
        seconds_of_day % 60
    )
}
fn civil_from_days(days: i64) -> (i64, u32, u32) {
    let z = days + 719_468;
    let era = z.div_euclid(146_097);
    let day_of_era = z.rem_euclid(146_097);
    let year_of_era =
        (day_of_era - day_of_era / 1_460 + day_of_era / 36_524 - day_of_era / 146_096) / 365;
    let year = year_of_era + era * 400;
    let day_of_year = day_of_era - (365 * year_of_era + year_of_era / 4 - year_of_era / 100);
    let shifted_month = (5 * day_of_year + 2) / 153;
    let day = (day_of_year - (153 * shifted_month + 2) / 5 + 1) as u32;
    let month = if shifted_month < 10 {
        shifted_month + 3
    } else {
        shifted_month - 9
    } as u32;
    (year + i64::from(month <= 2), month, day)
}
pub fn days_between(from_seconds: i64, to_seconds: i64) -> i32 {
    ((to_seconds - from_seconds).max(0) / 86_400) as i32
}