use thiserror::Error as ThisError;
#[derive(Debug, ThisError)]
pub enum DurationParseError {
#[error("invalid duration {value:?}; use positive seconds or a value ending in s, m, h, or d")]
Invalid { value: String },
}
pub fn parse_duration_seconds(value: &str) -> Result<u64, DurationParseError> {
let (number, multiplier) = match value.as_bytes().last().copied() {
Some(b's') => (&value[..value.len() - 1], 1),
Some(b'm') => (&value[..value.len() - 1], 60),
Some(b'h') => (&value[..value.len() - 1], 60 * 60),
Some(b'd') => (&value[..value.len() - 1], 24 * 60 * 60),
Some(b'0'..=b'9') => (value, 1),
_ => {
return Err(DurationParseError::Invalid {
value: value.to_string(),
});
}
};
number
.parse::<u64>()
.ok()
.and_then(|amount| amount.checked_mul(multiplier))
.filter(|seconds| *seconds > 0)
.ok_or_else(|| DurationParseError::Invalid {
value: value.to_string(),
})
}
#[must_use]
pub fn display_duration_seconds(seconds: u64) -> String {
const MINUTE: u64 = 60;
const HOUR: u64 = 60 * MINUTE;
const DAY: u64 = 24 * HOUR;
if seconds == 0 {
"0s".to_string()
} else if seconds >= DAY {
scaled_duration_unit_text(seconds, DAY, "d")
} else if seconds >= HOUR {
scaled_duration_unit_text(seconds, HOUR, "h")
} else if seconds >= MINUTE {
scaled_duration_unit_text(seconds, MINUTE, "m")
} else {
format!("{seconds}s")
}
}
fn scaled_duration_unit_text(seconds: u64, unit_seconds: u64, suffix: &str) -> String {
if seconds.is_multiple_of(unit_seconds) {
return format!("{}{suffix}", seconds / unit_seconds);
}
let hundredths =
((u128::from(seconds) * 100) + (u128::from(unit_seconds) / 2)) / u128::from(unit_seconds);
let whole = hundredths / 100;
let fractional = hundredths % 100;
format!("{whole}.{fractional:02}{suffix}")
}
#[cfg(test)]
mod tests {
use super::{display_duration_seconds, parse_duration_seconds};
#[test]
fn duration_display_uses_largest_readable_unit() {
assert_eq!(display_duration_seconds(0), "0s");
assert_eq!(display_duration_seconds(86_400), "1d");
assert_eq!(display_duration_seconds(2_629_800), "30.44d");
assert_eq!(display_duration_seconds(5_400), "1.50h");
assert_eq!(display_duration_seconds(90), "1.50m");
assert_eq!(display_duration_seconds(45), "45s");
}
#[test]
fn duration_parser_accepts_integer_units() {
assert_eq!(parse_duration_seconds("45").expect("seconds"), 45);
assert_eq!(parse_duration_seconds("30m").expect("minutes"), 1_800);
assert_eq!(parse_duration_seconds("2h").expect("hours"), 7_200);
assert_eq!(parse_duration_seconds("1d").expect("days"), 86_400);
assert!(parse_duration_seconds("0").is_err());
assert!(parse_duration_seconds("1.5h").is_err());
}
}