canic-cli 0.36.10

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

pub fn current_backup_directory_stamp() -> String {
    let seconds = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map_or(0, |duration| duration.as_secs());

    backup_directory_stamp_from_unix(seconds)
}

pub fn backup_directory_stamp_from_unix(seconds: u64) -> String {
    let days = i64::try_from(seconds / 86_400).unwrap_or(i64::MAX);
    let seconds_of_day = seconds % 86_400;
    let (year, month, day) = civil_from_days(days);
    let hour = seconds_of_day / 3_600;
    let minute = (seconds_of_day % 3_600) / 60;
    let second = seconds_of_day % 60;

    format!("{year:04}{month:02}{day:02}-{hour:02}{minute:02}{second:02}")
}

pub fn backup_directory_stamp_to_unix(stamp: &str) -> Option<u64> {
    let (date, time) = stamp.split_once('-')?;
    if date.len() != 8
        || time.len() != 6
        || !date.bytes().all(|byte| byte.is_ascii_digit())
        || !time.bytes().all(|byte| byte.is_ascii_digit())
    {
        return None;
    }

    let year = date[0..4].parse::<i64>().ok()?;
    let month = date[4..6].parse::<i64>().ok()?;
    let day = date[6..8].parse::<i64>().ok()?;
    let hour = time[0..2].parse::<u64>().ok()?;
    let minute = time[2..4].parse::<u64>().ok()?;
    let second = time[4..6].parse::<u64>().ok()?;
    if !(1..=12).contains(&month) || hour >= 24 || minute >= 60 || second >= 60 {
        return None;
    }

    let days = days_from_civil(year, month, day);
    if days < 0 || civil_from_days(days) != (year, month, day) {
        return None;
    }
    u64::try_from(days)
        .ok()?
        .checked_mul(86_400)?
        .checked_add(hour.checked_mul(3_600)?)?
        .checked_add(minute.checked_mul(60)?)?
        .checked_add(second)
}

pub fn backup_list_timestamp(seconds: u64) -> String {
    let days = i64::try_from(seconds / 86_400).unwrap_or(i64::MAX);
    let seconds_of_day = seconds % 86_400;
    let (year, month, day) = civil_from_days(days);
    let hour = seconds_of_day / 3_600;
    let minute = (seconds_of_day % 3_600) / 60;

    format!("{day:02}/{month:02}/{year:04} {hour:02}:{minute:02}")
}

pub fn unix_timestamp_marker_from_directory_stamp(stamp: &str) -> Option<String> {
    backup_directory_stamp_to_unix(stamp).map(|seconds| format!("unix:{seconds}"))
}

pub fn file_safe_component(value: &str) -> String {
    let cleaned = value
        .chars()
        .map(|ch| {
            if ch.is_ascii_alphanumeric() || matches!(ch, '-' | '_' | '.') {
                ch
            } else {
                '-'
            }
        })
        .collect::<String>();
    let cleaned = cleaned.trim_matches('-');
    if cleaned.is_empty() {
        "unknown".to_string()
    } else {
        cleaned.to_string()
    }
}

// Convert a proleptic Gregorian UTC date into days since 1970-01-01.
const fn days_from_civil(year: i64, month: i64, day: i64) -> i64 {
    let year = year - (month <= 2) as i64;
    let era = if year >= 0 { year } else { year - 399 } / 400;
    let year_of_era = year - era * 400;
    let month_prime = month + if month > 2 { -3 } else { 9 };
    let day_of_year = (153 * month_prime + 2) / 5 + day - 1;
    let day_of_era = year_of_era * 365 + year_of_era / 4 - year_of_era / 100 + day_of_year;

    era * 146_097 + day_of_era - 719_468
}

// Convert days since 1970-01-01 into a proleptic Gregorian UTC date.
const fn civil_from_days(days: i64) -> (i64, i64, i64) {
    let z = days + 719_468;
    let era = if z >= 0 { z } else { z - 146_096 } / 146_097;
    let doe = z - era * 146_097;
    let yoe = (doe - doe / 1_460 + doe / 36_524 - doe / 146_096) / 365;
    let year = yoe + era * 400;
    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
    let mp = (5 * doy + 2) / 153;
    let day = doy - (153 * mp + 2) / 5 + 1;
    let month = mp + if mp < 10 { 3 } else { -9 };
    let year = year + (month <= 2) as i64;

    (year, month, day)
}