Function format_epoch_ms

crates/openshell-cli/src/run.rs:169–195

Format milliseconds since Unix epoch as a `YYYY-MM-DD HH:MM:SS` UTC string.

(ms: i64)

/// Format milliseconds since Unix epoch as a `YYYY-MM-DD HH:MM:SS` UTC string.
fn format_epoch_ms(ms: i64) -> String {
    use std::time::UNIX_EPOCH;

    let Ok(ms_u64) = u64::try_from(ms) else {
        return "-".to_string();
    };
    let Ok(time) = UNIX_EPOCH
        .checked_add(Duration::from_millis(ms_u64))
        .ok_or(())
    else {
        return "-".to_string();
    };
    let Ok(dur) = time.duration_since(UNIX_EPOCH) else {
        return "-".to_string();
    };

    let secs = dur.as_secs();
    let days = secs / 86400;
    let time_of_day = secs % 86400;
    let hours = time_of_day / 3600;
    let minutes = (time_of_day % 3600) / 60;
    let seconds = time_of_day % 60;

    // Convert days since epoch to year-month-day using a basic civil calendar algorithm.
    let (y, m, d) = civil_from_days(days);
    format!("{y:04}-{m:02}-{d:02} {hours:02}:{minutes:02}:{seconds:02}")
}

/// Convert days since 1970-01-01 to (year, month, day).
/// Algorithm from Howard Hinnant's `chrono`-compatible date library.