shipper-duration 0.3.0-rc.2

//! Duration parsing and serde codecs for shipper.
//!
//! This crate centralizes duration handling so CLI parsing and config/state
//! serde use one implementation.

use std::time::Duration;

use serde::{Deserialize, Deserializer, Serializer};

/// Parse a human-readable duration string (for example `2s`, `500ms`, `1m`).
///
/// # Examples
///
/// ```
/// use std::time::Duration;
/// use shipper_duration::parse_duration;
///
/// assert_eq!(parse_duration("2s").unwrap(), Duration::from_secs(2));
/// assert_eq!(parse_duration("500ms").unwrap(), Duration::from_millis(500));
/// assert_eq!(parse_duration("1m").unwrap(), Duration::from_secs(60));
/// ```
pub fn parse_duration(input: &str) -> Result<Duration, humantime::DurationError> {
    humantime::parse_duration(input)
}

/// Deserialize a [`Duration`] from either a human-readable string or a millisecond integer.
pub fn deserialize_duration<'de, D>(deserializer: D) -> Result<Duration, D::Error>
where
    D: Deserializer<'de>,
{
    #[derive(Deserialize)]
    #[serde(untagged)]
    enum DurationHelper {
        String(String),
        U64(u64),
    }

    match DurationHelper::deserialize(deserializer)? {
        DurationHelper::String(s) => parse_duration(&s)
            .map_err(|e| serde::de::Error::custom(format!("invalid duration: {e}"))),
        DurationHelper::U64(ms) => Ok(Duration::from_millis(ms)),
    }
}

/// Serialize a [`Duration`] as milliseconds (`u64`) for stable round-tripping.
pub fn serialize_duration<S>(duration: &Duration, serializer: S) -> Result<S::Ok, S::Error>
where
    S: Serializer,
{
    serializer.serialize_u64(duration.as_millis() as u64)
}

#[cfg(test)]
mod tests {
    use super::*;
    use proptest::prelude::*;

    #[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
    struct DurationHolder {
        #[serde(
            deserialize_with = "deserialize_duration",
            serialize_with = "serialize_duration"
        )]
        value: Duration,
    }

    #[test]
    fn parse_duration_accepts_human_readable_values() {
        assert_eq!(
            parse_duration("250ms").expect("parse"),
            Duration::from_millis(250)
        );
        assert_eq!(parse_duration("2s").expect("parse"), Duration::from_secs(2));
    }

    #[test]
    fn deserialize_accepts_number_and_string() {
        let from_num: DurationHolder = serde_json::from_str(r#"{"value":1500}"#).expect("json");
        assert_eq!(from_num.value, Duration::from_millis(1500));

        let from_str: DurationHolder = serde_json::from_str(r#"{"value":"1500ms"}"#).expect("json");
        assert_eq!(from_str.value, Duration::from_millis(1500));
    }

    #[test]
    fn serialize_writes_milliseconds() {
        let value = DurationHolder {
            value: Duration::from_millis(4321),
        };
        let json = serde_json::to_value(&value).expect("json");
        assert_eq!(json["value"], 4321);
    }

    #[test]
    fn deserialize_rejects_invalid_duration_string() {
        let err = serde_json::from_str::<DurationHolder>(r#"{"value":"not-a-duration"}"#)
            .expect_err("must fail");
        assert!(err.to_string().contains("invalid duration"));
    }

    proptest! {
        #[test]
        fn duration_roundtrips_as_milliseconds(ms in 0_u64..10_000_000_000) {
            let holder = DurationHolder {
                value: Duration::from_millis(ms),
            };

            let json = serde_json::to_string(&holder).expect("serialize");
            let reparsed: DurationHolder = serde_json::from_str(&json).expect("deserialize");

            prop_assert_eq!(reparsed, holder);
        }
    }

    #[test]
    fn serde_json_full_roundtrip() {
        let holder = DurationHolder {
            value: Duration::from_secs(3661),
        };
        let json = serde_json::to_string(&holder).unwrap();
        let reparsed: DurationHolder = serde_json::from_str(&json).unwrap();
        assert_eq!(reparsed, holder);
    }

    #[test]
    fn serde_toml_string_deserialization() {
        let toml_str = r#"value = "2m 30s""#;
        let holder: DurationHolder = toml::from_str(toml_str).unwrap();
        assert_eq!(holder.value, Duration::from_secs(150));
    }

    #[test]
    fn deserialize_rejects_boolean() {
        let err =
            serde_json::from_str::<DurationHolder>(r#"{"value":true}"#).expect_err("must fail");
        assert!(!err.to_string().is_empty());
    }

    #[test]
    fn deserialize_rejects_float() {
        let err =
            serde_json::from_str::<DurationHolder>(r#"{"value":1.5}"#).expect_err("must fail");
        assert!(!err.to_string().is_empty());
    }
}

#[cfg(test)]
mod proptests {
    use super::*;
    use proptest::prelude::*;

    #[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
    struct DurationHolder {
        #[serde(
            deserialize_with = "deserialize_duration",
            serialize_with = "serialize_duration"
        )]
        value: Duration,
    }

    proptest! {
        /// Human-readable formatting always produces a non-empty string.
        #[test]
        fn format_is_never_empty(ms in 0u64..10_000_000_000u64) {
            let d = Duration::from_millis(ms);
            let formatted = humantime::format_duration(d).to_string();
            prop_assert!(!formatted.is_empty(), "formatted duration was empty for {ms}ms");
        }

        /// Formatting the same duration twice always yields the same string.
        #[test]
        fn format_consistency(ms in 0u64..10_000_000_000u64) {
            let d = Duration::from_millis(ms);
            let first = humantime::format_duration(d).to_string();
            let second = humantime::format_duration(d).to_string();
            prop_assert_eq!(first, second);
        }

        /// format → parse round-trip preserves the original duration.
        #[test]
        fn parse_format_roundtrip(ms in 0u64..10_000_000u64) {
            let d = Duration::from_millis(ms);
            let formatted = humantime::format_duration(d).to_string();
            let parsed = parse_duration(&formatted).expect("should parse formatted duration");
            prop_assert_eq!(parsed, d);
        }

        /// Sub-second durations mention "ms" in the formatted output.
        #[test]
        fn millisecond_range_contains_ms(ms in 1u64..1000u64) {
            let d = Duration::from_millis(ms);
            let formatted = humantime::format_duration(d).to_string();
            prop_assert!(formatted.contains("ms"), "expected 'ms' in \"{formatted}\"");
        }

        /// Whole-second durations (< 1 min) mention "s" in the formatted output.
        #[test]
        fn seconds_range_contains_s(secs in 1u64..60u64) {
            let d = Duration::from_secs(secs);
            let formatted = humantime::format_duration(d).to_string();
            prop_assert!(formatted.contains('s'), "expected 's' in \"{formatted}\"");
        }

        /// Whole-minute durations mention "m" in the formatted output.
        #[test]
        fn minutes_range_contains_m(mins in 1u64..60u64) {
            let d = Duration::from_secs(mins * 60);
            let formatted = humantime::format_duration(d).to_string();
            prop_assert!(formatted.contains('m'), "expected 'm' in \"{formatted}\"");
        }

        /// Whole-hour durations mention "h" in the formatted output.
        #[test]
        fn hours_range_contains_h(hours in 1u64..24u64) {
            let d = Duration::from_secs(hours * 3600);
            let formatted = humantime::format_duration(d).to_string();
            prop_assert!(formatted.contains('h'), "expected 'h' in \"{formatted}\"");
        }

        /// Serde JSON round-trip via integer millisecond representation.
        #[test]
        fn serde_json_u64_roundtrip(ms in 0u64..10_000_000_000u64) {
            let json = format!(r#"{{"value":{ms}}}"#);
            let holder: DurationHolder = serde_json::from_str(&json).expect("deserialize");
            prop_assert_eq!(holder.value, Duration::from_millis(ms));
        }

        /// Serde TOML round-trip via human-readable string representation.
        #[test]
        fn serde_toml_string_roundtrip(ms in 1u64..10_000_000u64) {
            let d = Duration::from_millis(ms);
            let formatted = humantime::format_duration(d).to_string();
            let toml_str = format!("value = \"{formatted}\"");
            let holder: DurationHolder = toml::from_str(&toml_str).expect("toml deserialize");
            prop_assert_eq!(holder.value, d);
        }

        /// Arbitrary UTF-8 strings never cause parse_duration to panic.
        #[test]
        fn arbitrary_strings_never_panic(s in "\\PC{0,64}") {
            let _ = parse_duration(&s);
        }

        /// Adding two durations then formatting and reparsing produces the sum.
        #[test]
        fn combined_duration_format_roundtrip(
            a_ms in 0u64..1_000_000u64,
            b_ms in 0u64..1_000_000u64,
        ) {
            let combined = Duration::from_millis(a_ms) + Duration::from_millis(b_ms);
            let formatted = humantime::format_duration(combined).to_string();
            let parsed = parse_duration(&formatted).expect("should parse formatted combined duration");
            prop_assert_eq!(parsed, combined);
        }
    }
}

#[cfg(test)]
mod edge_case_tests {
    use super::*;

    // -- Zero duration --

    #[test]
    fn parse_zero_ms() {
        assert_eq!(parse_duration("0ms").unwrap(), Duration::ZERO);
    }

    #[test]
    fn parse_zero_seconds() {
        assert_eq!(parse_duration("0s").unwrap(), Duration::ZERO);
    }

    #[test]
    fn deserialize_zero_from_integer() {
        #[derive(serde::Deserialize)]
        struct H {
            #[serde(deserialize_with = "deserialize_duration")]
            v: Duration,
        }
        let h: H = serde_json::from_str(r#"{"v":0}"#).unwrap();
        assert_eq!(h.v, Duration::ZERO);
    }

    #[test]
    fn serialize_zero_is_zero() {
        #[derive(serde::Serialize)]
        struct H {
            #[serde(serialize_with = "serialize_duration")]
            v: Duration,
        }
        let json = serde_json::to_value(H { v: Duration::ZERO }).unwrap();
        assert_eq!(json["v"], 0);
    }

    // -- Large durations --

    #[test]
    fn parse_large_hours() {
        let d = parse_duration("9999h").unwrap();
        assert_eq!(d, Duration::from_secs(9999 * 3600));
    }

    #[test]
    fn serialize_large_millis() {
        #[derive(serde::Serialize)]
        struct H {
            #[serde(serialize_with = "serialize_duration")]
            v: Duration,
        }
        let large = Duration::from_secs(365 * 24 * 3600); // 1 year
        let json = serde_json::to_value(H { v: large }).unwrap();
        assert_eq!(json["v"], 365 * 24 * 3600 * 1000_u64);
    }

    // -- Sub-millisecond precision --

    #[test]
    fn parse_microseconds() {
        let d = parse_duration("500us").unwrap();
        assert_eq!(d, Duration::from_micros(500));
    }

    #[test]
    fn parse_nanoseconds() {
        let d = parse_duration("100ns").unwrap();
        assert_eq!(d, Duration::from_nanos(100));
    }

    #[test]
    fn serialize_truncates_sub_millis_to_zero() {
        // Duration with only microseconds → as_millis() == 0
        #[derive(serde::Serialize)]
        struct H {
            #[serde(serialize_with = "serialize_duration")]
            v: Duration,
        }
        let d = Duration::from_micros(999);
        let json = serde_json::to_value(H { v: d }).unwrap();
        assert_eq!(json["v"], 0);
    }

    // -- Parsing edge cases --

    #[test]
    fn parse_empty_string_is_error() {
        assert!(parse_duration("").is_err());
    }

    #[test]
    fn parse_whitespace_only_is_error() {
        assert!(parse_duration("   ").is_err());
    }

    #[test]
    fn parse_combined_units() {
        let d = parse_duration("1h 30m 15s").unwrap();
        assert_eq!(d, Duration::from_secs(3600 + 30 * 60 + 15));
    }

    #[test]
    fn parse_day_unit() {
        let d = parse_duration("2days").unwrap();
        assert_eq!(d, Duration::from_secs(2 * 86400));
    }

    // -- Comparison / ordering --

    #[test]
    fn parsed_durations_maintain_ordering() {
        let a = parse_duration("500ms").unwrap();
        let b = parse_duration("1s").unwrap();
        let c = parse_duration("1m").unwrap();
        let d = parse_duration("1h").unwrap();
        assert!(a < b);
        assert!(b < c);
        assert!(c < d);
    }

    // -- Arithmetic --

    #[test]
    fn parsed_durations_support_addition() {
        let a = parse_duration("30s").unwrap();
        let b = parse_duration("30s").unwrap();
        assert_eq!(a + b, Duration::from_secs(60));
    }

    #[test]
    fn parsed_durations_support_subtraction() {
        let a = parse_duration("2m").unwrap();
        let b = parse_duration("30s").unwrap();
        assert_eq!(a - b, Duration::from_secs(90));
    }

    #[test]
    fn parsed_duration_supports_multiplication() {
        let a = parse_duration("500ms").unwrap();
        assert_eq!(a * 4, Duration::from_secs(2));
    }

    // -- Combined units without spaces --

    #[test]
    fn parse_combined_no_spaces() {
        assert_eq!(
            parse_duration("1h30m").unwrap(),
            Duration::from_secs(3600 + 30 * 60)
        );
        assert_eq!(
            parse_duration("2m30s").unwrap(),
            Duration::from_secs(2 * 60 + 30)
        );
    }

    // -- Zero forms equivalence --

    #[test]
    fn parse_zero_forms_are_equivalent() {
        let zero = Duration::ZERO;
        assert_eq!(parse_duration("0s").unwrap(), zero);
        assert_eq!(parse_duration("0ms").unwrap(), zero);
        assert_eq!(parse_duration("0ns").unwrap(), zero);
        assert_eq!(parse_duration("0us").unwrap(), zero);
    }

    // -- Invalid input patterns --

    #[test]
    fn parse_number_without_unit_is_error() {
        assert!(parse_duration("42").is_err());
    }

    #[test]
    fn parse_unknown_unit_is_error() {
        assert!(parse_duration("5xyz").is_err());
    }

    #[test]
    fn parse_negative_is_error() {
        assert!(parse_duration("-5s").is_err());
    }

    #[test]
    fn parse_overflow_is_error() {
        assert!(parse_duration("99999999999999999999999999999s").is_err());
    }

    // -- Format-parse roundtrips --

    #[test]
    fn format_then_parse_roundtrip_deterministic() {
        let cases = [
            Duration::ZERO,
            Duration::from_millis(250),
            Duration::from_secs(42),
            Duration::from_secs(3661),
            Duration::from_secs(90061),
        ];
        for d in cases {
            let formatted = humantime::format_duration(d).to_string();
            let parsed = parse_duration(&formatted).unwrap();
            assert_eq!(parsed, d, "roundtrip failed for {formatted}");
        }
    }

    // -- Complex multi-unit combinations --

    #[test]
    fn parse_days_hours_minutes_combined() {
        let d = parse_duration("1day 2h 30m").unwrap();
        assert_eq!(d, Duration::from_secs(86400 + 2 * 3600 + 30 * 60));
    }
}

#[cfg(test)]
mod snapshot_tests {
    use super::*;
    use insta::assert_debug_snapshot;

    #[test]
    fn snapshot_parsed_zero() {
        assert_debug_snapshot!(parse_duration("0s").unwrap());
    }

    #[test]
    fn snapshot_parsed_millis() {
        assert_debug_snapshot!(parse_duration("250ms").unwrap());
    }

    #[test]
    fn snapshot_parsed_seconds() {
        assert_debug_snapshot!(parse_duration("42s").unwrap());
    }

    #[test]
    fn snapshot_parsed_minutes() {
        assert_debug_snapshot!(parse_duration("5m").unwrap());
    }

    #[test]
    fn snapshot_parsed_hours() {
        assert_debug_snapshot!(parse_duration("2h").unwrap());
    }

    #[test]
    fn snapshot_parsed_combined() {
        assert_debug_snapshot!(parse_duration("1h 30m 15s 200ms").unwrap());
    }

    #[test]
    fn snapshot_parse_error() {
        assert_debug_snapshot!(parse_duration("not-valid"));
    }

    #[test]
    fn snapshot_deserialized_from_integer() {
        #[derive(Debug, serde::Deserialize)]
        #[allow(dead_code)]
        struct H {
            #[serde(deserialize_with = "deserialize_duration")]
            v: Duration,
        }
        let h: H = serde_json::from_str(r#"{"v":3661000}"#).unwrap();
        assert_debug_snapshot!(h);
    }

    #[test]
    fn snapshot_deserialized_from_string() {
        #[derive(Debug, serde::Deserialize)]
        #[allow(dead_code)]
        struct H {
            #[serde(deserialize_with = "deserialize_duration")]
            v: Duration,
        }
        let h: H = serde_json::from_str(r#"{"v":"1h 1m 1s"}"#).unwrap();
        assert_debug_snapshot!(h);
    }

    #[test]
    fn snapshot_formatted_common_durations() {
        let formatted: Vec<(&str, String)> = vec![
            ("zero", Duration::ZERO),
            ("half_second", Duration::from_millis(500)),
            ("one_minute", Duration::from_secs(60)),
            ("one_hour_one_min_one_sec", Duration::from_secs(3661)),
            ("one_day", Duration::from_secs(86400)),
        ]
        .into_iter()
        .map(|(name, d)| (name, humantime::format_duration(d).to_string()))
        .collect();
        assert_debug_snapshot!(formatted);
    }

    #[test]
    fn snapshot_parse_errors_various() {
        let results: Vec<(&str, String)> = vec!["", "   ", "42", "-5s", "5xyz"]
            .into_iter()
            .map(|input| (input, parse_duration(input).unwrap_err().to_string()))
            .collect();
        assert_debug_snapshot!(results);
    }
}