deep-time 0.1.0-beta.31

#![allow(clippy::all, clippy::pedantic, clippy::restriction, warnings)]

use deep_time::civil_parts::{Offset, Parts, Weekday};
use deep_time::consts::{ATTOS_PER_SEC_I128, SEC_PER_DAY_I64};
use deep_time::macros::as_ms;
use deep_time::{Dt, DtErrKind, Scale};

mod from_str_tests {
    use super::*;

    #[test]
    fn test_iso_offset_directly_after_date() {
        // Offset with no time component
        let tp = Parts::from_str("2023-01-01+05:00").unwrap();
        assert_eq!(tp.yr, Some(2023));
        assert_eq!(tp.mo, Some(1));
        assert_eq!(tp.day, Some(1));
        assert_eq!(tp.hr, 0);
        assert_eq!(tp.min, 0);
        assert_eq!(tp.sec, 0);
        assert_eq!(tp.offset, Some(Offset::Fixed(5 * 3600)));

        // Negative offset, compact form
        let tp = Parts::from_str("2023-001-0530").unwrap();
        assert_eq!(tp.day_of_yr, Some(1));
        assert_eq!(tp.offset, Some(Offset::Fixed(-5 * 3600 - 30 * 60)));
    }

    #[test]
    fn test_iso_offset_after_time() {
        let tp = Parts::from_str("2024-04-18T14:30:25+02:00").unwrap();
        assert_eq!(tp.yr, Some(2024));
        assert_eq!(tp.mo, Some(4));
        assert_eq!(tp.day, Some(18));
        assert_eq!(tp.hr, 14);
        assert_eq!(tp.min, 30);
        assert_eq!(tp.sec, 25);
        assert_eq!(tp.offset, Some(Offset::Fixed(2 * 3600)));

        // With Z and offset
        let tp = Parts::from_str("2024-04-18T14:30:25Z-05:30").unwrap();
        assert_eq!(tp.offset, Some(Offset::Fixed(-5 * 3600 - 30 * 60)));
    }

    #[test]
    fn test_iso_compact_offset() {
        let tp = Parts::from_str("2023-12-25T00:00:00+0530").unwrap();
        assert_eq!(tp.offset, Some(Offset::Fixed(5 * 3600 + 30 * 60)));

        let tp = Parts::from_str("2023-12-25+0000").unwrap();
        assert_eq!(tp.offset, Some(Offset::Fixed(0)));
    }

    #[test]
    fn test_iso_offset_minutes_range() {
        // Minutes > 59 → InvalidOffsetMinute (colon and compact forms).
        let err = Parts::from_str("2024-01-01+00:60").unwrap_err();
        assert!(matches!(err.kind(), DtErrKind::InvalidOffsetMinute));
        let err = Parts::from_str("2024-01-01+0060").unwrap_err();
        assert!(matches!(err.kind(), DtErrKind::InvalidOffsetMinute));
        let err = Parts::from_str("2024-01-01T12:00:00-14:99").unwrap_err();
        assert!(matches!(err.kind(), DtErrKind::InvalidOffsetMinute));

        // Minutes = 59 is fine; hours are not range-checked.
        let tp = Parts::from_str("2024-01-01+00:59").unwrap();
        assert_eq!(tp.offset, Some(Offset::Fixed(59 * 60)));
        let tp = Parts::from_str("2024-01-01+99:00").unwrap();
        assert_eq!(tp.offset, Some(Offset::Fixed(99 * 3600)));
        let tp = Parts::from_str("2024-01-01-24:30").unwrap();
        assert_eq!(tp.offset, Some(Offset::Fixed(-(24 * 3600 + 30 * 60))));

        // Hours-only and single-digit forms still work.
        let tp = Parts::from_str("2024-01-01+5").unwrap();
        assert_eq!(tp.offset, Some(Offset::Fixed(5 * 3600)));
        let tp = Parts::from_str("2024-01-01+5:30").unwrap();
        assert_eq!(tp.offset, Some(Offset::Fixed(5 * 3600 + 30 * 60)));
    }

    #[test]
    fn test_iso_iana_name() {
        let tp = Parts::from_str("2024-04-18T14:30:25 [America/New_York]").unwrap();
        assert_eq!(tp.yr, Some(2024));
        assert_eq!(tp.mo, Some(4));
        assert_eq!(tp.day, Some(18));
        assert_eq!(tp.hr, 14);
        assert_eq!(tp.min, 30);
        assert_eq!(tp.sec, 25);
        assert_eq!(tp.offset, None); // no offset in this case
        // iana_name is set via set_iana_name (BufStr), so we just check it's Some
        assert!(tp.iana_name.is_some());
    }

    #[test]
    fn test_iso_offset_and_iana() {
        let tp = Parts::from_str("2024-04-18T14:30:25+02:00 [Europe/Paris]").unwrap();
        assert_eq!(tp.offset, Some(Offset::Fixed(2 * 3600)));
        assert!(tp.iana_name.is_some());
    }

    #[test]
    fn test_iso_full_example_from_docs() {
        // Matches the example in the doc comment
        let tp = Parts::from_str("+2000-01-01T17:00:00 -0500 [America/New_York] TAI").unwrap();

        assert_eq!(tp.yr, Some(2000));
        assert_eq!(tp.mo, Some(1));
        assert_eq!(tp.day, Some(1));
        assert_eq!(tp.hr, 17);
        assert_eq!(tp.min, 0);
        assert_eq!(tp.sec, 0);
        assert_eq!(tp.offset, Some(Offset::Fixed(-5 * 3600)));
        assert!(tp.iana_name.is_some());
        assert_eq!(tp.scale, Scale::TAI);
    }

    #[test]
    fn test_iso_negative_year() {
        let tp = Parts::from_str("-4714-11-24 12:00:00").unwrap();
        assert_eq!(tp.yr, Some(-4714));
        assert_eq!(tp.mo, Some(11));
        assert_eq!(tp.day, Some(24));
        assert_eq!(tp.hr, 12);
        assert_eq!(tp.min, 0);
        assert_eq!(tp.sec, 0);

        // Explicit positive year sign still works
        let tp = Parts::from_str("+0042-01-02T03:04:05").unwrap();
        assert_eq!(tp.yr, Some(42));
        assert_eq!(tp.mo, Some(1));
        assert_eq!(tp.day, Some(2));
    }

    #[test]
    fn test_iso_whitespace_variations() {
        let tp = Parts::from_str("2024-04-18  14:30:25   +02:00   [Europe/Berlin]   TAI").unwrap();
        assert_eq!(tp.hr, 14);
        assert_eq!(tp.offset, Some(Offset::Fixed(2 * 3600)));
        assert!(tp.iana_name.is_some());
        assert_eq!(tp.scale, Scale::TAI);
    }

    #[test]
    fn test_iso_iana_unclosed_bracket_error() {
        let result = Parts::from_str("2024-04-18T12:00:00 [America/New_York");
        assert!(result.is_err());
        // You can also assert the exact error kind if desired:
        // assert!(matches!(result, Err(e) if e.kind() == Some(DtErrKind::InvalidSyntax)));
    }

    #[test]
    fn test_iso_scale_after_iana() {
        let tp = Parts::from_str("2024-04-18T12:00:00 [America/New_York] GPS").unwrap();
        assert!(tp.iana_name.is_some());
        assert_eq!(tp.scale, Scale::GPS);
    }

    // Optional: test that bare +/- after date is handled gracefully (current lenient behavior)
    #[test]
    fn test_iso_bare_sign_after_date() {
        // Current behavior: consumes the sign but doesn't set offset
        let tp = Parts::from_str("2023-01-01+").unwrap();
        assert_eq!(tp.yr, Some(2023));
        assert_eq!(tp.mo, Some(1));
        assert_eq!(tp.day, Some(1));
        // offset remains default (not set)
    }

    #[test]
    fn test_ccsds_calendar_variants() {
        // Full calendar with fractional seconds + trailing Z
        let dt = Parts::from_str("2024-04-18T14:30:25.123456789Z").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.day_of_yr, None);
        assert_eq!(dt.hr, 14);
        assert_eq!(dt.min, 30);
        assert_eq!(dt.sec, 25);

        // Calendar with seconds, no fraction
        let dt = Parts::from_str("2024-04-18T14:30:25").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.hr, 14);
        assert_eq!(dt.min, 30);
        assert_eq!(dt.sec, 25);

        // Calendar with only minutes
        let dt = Parts::from_str("2024-04-18T14:30").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.hr, 14);
        assert_eq!(dt.min, 30);
        assert_eq!(dt.sec, 0);

        // Calendar with only hour
        let dt = Parts::from_str("2024-04-18T14").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.hr, 14);
        assert_eq!(dt.min, 0);
        assert_eq!(dt.sec, 0);

        // Calendar date-only
        let dt = Parts::from_str("2024-04-18").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.day_of_yr, None);
        assert_eq!(dt.hr, 0);
        assert_eq!(dt.min, 0);
        assert_eq!(dt.sec, 0);
    }

    #[test]
    fn test_ccsds_doy_variants() {
        // DOY with fractional seconds + Z
        let dt = Parts::from_str("2024-109T14:30:25.5Z").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.day_of_yr, Some(109));
        assert_eq!(dt.mo, None);
        assert_eq!(dt.day, None);
        assert_eq!(dt.hr, 14);
        assert_eq!(dt.min, 30);
        assert_eq!(dt.sec, 25);

        // DOY date-only
        let dt = Parts::from_str("2024-001").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.day_of_yr, Some(1));
        assert_eq!(dt.mo, None);
        assert_eq!(dt.day, None);

        // DOY with seconds only (no fraction)
        let dt = Parts::from_str("2024-366T23:59:59").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.day_of_yr, Some(366));
        assert_eq!(dt.hr, 23);
        assert_eq!(dt.min, 59);
        assert_eq!(dt.sec, 59);
    }

    #[test]
    fn test_ccsds_separators_and_z() {
        // Space instead of T
        let dt = Parts::from_str("2024-04-18 14:30:25").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.hr, 14);
        assert_eq!(dt.min, 30);
        assert_eq!(dt.sec, 25);

        // Lowercase t
        let dt = Parts::from_str("2024-109t14:30").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.day_of_yr, Some(109));
        assert_eq!(dt.hr, 14);
        assert_eq!(dt.min, 30);

        // Trailing Z (case-insensitive) is stripped and still works
        let dt = Parts::from_str("2024-04-18T14:30:25Z").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.hr, 14);
        assert_eq!(dt.min, 30);
        assert_eq!(dt.sec, 25);
    }

    #[test]
    fn test_ccsds_fractional_seconds_various_lengths() {
        // 1 digit
        let dt = Parts::from_str("2024-04-18T14:30:25.1").unwrap();
        assert_eq!(dt.attos, 100_000_000_000_000_000);

        // 3 digits
        let dt = Parts::from_str("2024-04-18T14:30:25.123").unwrap();
        assert_eq!(dt.attos, 123_000_000_000_000_000);

        // 6 digits
        let dt = Parts::from_str("2024-04-18T14:30:25.123456").unwrap();
        assert_eq!(dt.attos, 123_456_000_000_000_000);

        // 9 digits (full nanos)
        let dt = Parts::from_str("2024-04-18T14:30:25.123456789").unwrap();
        assert_eq!(dt.attos, 123_456_789_000_000_000);
    }

    #[test]
    fn test_ccsds_leap_second() {
        let dt = Parts::from_str("2024-06-30T23:59:60Z").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(6));
        assert_eq!(dt.day, Some(30));
        assert_eq!(dt.sec, 60);
    }

    #[test]
    fn test_ccsds_doy_vs_calendar_detection() {
        // Must be detected as DOY (exactly 3 digits after year separator, next char is not a digit)
        let doy = Parts::from_str("2024-123T12:00:00").unwrap();
        assert_eq!(doy.day_of_yr, Some(123));
        assert_eq!(doy.mo, None);
        assert_eq!(doy.day, None);

        // Must be detected as calendar date
        let cal = Parts::from_str("2024-12-03T12:00:00").unwrap();
        assert_eq!(cal.mo, Some(12));
        assert_eq!(cal.day, Some(3));
        assert_eq!(cal.day_of_yr, None);
    }

    #[test]
    fn test_from_str_junk() {
        // skip junk before and after the timestamp
        let x = Parts::from_str("sdfsdfs sdfsdf 2024-123T12:00:00dsfsdf").unwrap();
        assert_eq!(x.yr, Some(2024));
        assert_eq!(x.day_of_yr, Some(123));
        assert_eq!(x.mo, None);
        assert_eq!(x.day, None);
        assert_eq!(x.hr, 12);
        assert_eq!(x.min, 0);
        assert_eq!(x.sec, 0);
        assert_eq!(x.attos, 0); // defaults to 0 attos
        assert_eq!(x.scale, Scale::UTC); // default scale when none given

        // parse scale at the end (late scale)
        let x = Parts::from_str("sdfsdfs sdfsdf 2024-123T12:00:00 TDB").unwrap();
        assert_eq!(x.yr, Some(2024));
        assert_eq!(x.day_of_yr, Some(123));
        assert_eq!(x.hr, 12);
        assert_eq!(x.min, 0);
        assert_eq!(x.sec, 0);
        assert_eq!(x.scale, Scale::TDB);

        // parse scale at the end with trailing Z
        let x = Parts::from_str("sdfsdfs sdfsdf 2024-123T12:00:00Z TDB").unwrap();
        assert_eq!(x.yr, Some(2024));
        assert_eq!(x.day_of_yr, Some(123));
        assert_eq!(x.hr, 12);
        assert_eq!(x.min, 0);
        assert_eq!(x.sec, 0);
        assert_eq!(x.scale, Scale::TDB);

        // parse early scale (right after DOY, no time)
        let x = Parts::from_str("sdfsdfs sdfsdf 2024-123TDB fdsfsdfsdf").unwrap();
        assert_eq!(x.yr, Some(2024));
        assert_eq!(x.day_of_yr, Some(123));
        assert_eq!(x.hr, 0); // time is optional
        assert_eq!(x.min, 0);
        assert_eq!(x.sec, 0);
        assert_eq!(x.scale, Scale::TDB);
    }

    #[test]
    fn test_ccsds_early_and_late_scale() {
        // === EARLY scale (right after date) ===
        let dt = Parts::from_str("2024-001TAI").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.day_of_yr, Some(1));
        assert_eq!(dt.scale, Scale::TAI);

        let dt = Parts::from_str("2024-04-18 TDB").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.scale, Scale::TDB);

        // === EARLY scale + time ===
        let dt = Parts::from_str("2024-109T12:00:00LTC").unwrap();
        assert_eq!(dt.day_of_yr, Some(109));
        assert_eq!(dt.hr, 12);
        assert_eq!(dt.min, 0);
        assert_eq!(dt.sec, 0);
        assert_eq!(dt.scale, Scale::LTC);

        let dt = Parts::from_str("2024-04-18 14:30:25 UTC").unwrap();
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.hr, 14);
        assert_eq!(dt.min, 30);
        assert_eq!(dt.sec, 25);
        assert_eq!(dt.scale, Scale::UTC);

        // === LATE scale (after time) ===
        let dt = Parts::from_str("2024-001T12:00:00 TDB").unwrap();
        assert_eq!(dt.day_of_yr, Some(1));
        assert_eq!(dt.hr, 12);
        assert_eq!(dt.scale, Scale::TDB);

        let dt = Parts::from_str("2024-06-30T23:59:60Z GPS").unwrap();
        assert_eq!(dt.sec, 60);
        assert_eq!(dt.scale, Scale::GPS);

        // === BOTH orders with fractional seconds ===
        let dt = Parts::from_str("2024-04-18T14:30:25.123456789 TCL").unwrap();
        assert_eq!(dt.scale, Scale::TCL);
        assert_eq!(dt.attos, 123_456_789_000_000_000);

        let dt = Parts::from_str("2024-109 14:30:25.5 TAI").unwrap();
        assert_eq!(dt.scale, Scale::TAI);
        assert_eq!(dt.attos, 500_000_000_000_000_000);

        // === Time completely optional, scale only ===
        let dt = Parts::from_str("2024-001 TAI").unwrap();
        assert_eq!(dt.day_of_yr, Some(1));
        assert_eq!(dt.scale, Scale::TAI);
        assert_eq!(dt.hr, 0); // defaults
        assert_eq!(dt.min, 0);
        assert_eq!(dt.sec, 0);

        let dt = Parts::from_str("2024-04-18UTC").unwrap();
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.scale, Scale::UTC);
    }

    #[test]
    fn test_ccsds_scale_case_insensitivity_and_variants() {
        for scale_str in &[
            "TAI", "tai", "Tai", "UTC", "utc", "TDB", "ltc", "TCL", "GPS", "gst",
        ] {
            let s = format!("2024-001T12:00:00 {}", scale_str);
            let dt = Parts::from_str(&s).unwrap();
            assert!(dt.scale != Scale::Custom, "failed to parse {}", scale_str);
        }
    }

    #[test]
    fn test_ccsds_no_time_no_scale_still_works() {
        let dt = Parts::from_str("2024-001").unwrap();
        assert_eq!(dt.day_of_yr, Some(1));
        assert_eq!(dt.scale, Scale::UTC); // default is UTC

        let dt = Parts::from_str("2024-04-18").unwrap();
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));
        assert_eq!(dt.scale, Scale::UTC); // default is UTC
    }

    #[test]
    fn test_iso_single_digit_month_day() {
        // single digit month and day
        let dt = Parts::from_str("2024-1-1").unwrap();
        assert_eq!(dt.yr, Some(2024));
        assert_eq!(dt.mo, Some(1));
        assert_eq!(dt.day, Some(1));

        // mixed
        let dt = Parts::from_str("2024-4-18").unwrap();
        assert_eq!(dt.mo, Some(4));
        assert_eq!(dt.day, Some(18));

        let dt = Parts::from_str("2024-12-5").unwrap();
        assert_eq!(dt.mo, Some(12));
        assert_eq!(dt.day, Some(5));

        // with time
        let dt = Parts::from_str("2024-1-2T03:04:05").unwrap();
        assert_eq!(dt.mo, Some(1));
        assert_eq!(dt.day, Some(2));
        assert_eq!(dt.hr, 3);

        // with offset, no time
        let dt = Parts::from_str("2024-5-6+02:00").unwrap();
        assert_eq!(dt.mo, Some(5));
        assert_eq!(dt.day, Some(6));
        assert_eq!(dt.offset, Some(Offset::Fixed(2 * 3600)));

        // date only, single digits, default scale
        let dt = Parts::from_str("2025-9-9").unwrap();
        assert_eq!(dt.mo, Some(9));
        assert_eq!(dt.day, Some(9));

        let _dt = Dt::from_str("2024-1-5T12:00:00Z").unwrap();
    }

    #[test]
    fn test_iso_partial_dates() {
        // Year only → 1 Jan
        let p = Parts::from_str("2024").unwrap();
        assert_eq!((p.yr, p.mo, p.day), (Some(2024), Some(1), Some(1)));

        let p = Parts::from_str("2024-").unwrap();
        assert_eq!((p.mo, p.day), (Some(1), Some(1)));

        // Year-month → day 1
        let p = Parts::from_str("2024-03").unwrap();
        assert_eq!((p.mo, p.day), (Some(3), Some(1)));

        let p = Parts::from_str("2024-3").unwrap();
        assert_eq!((p.mo, p.day), (Some(3), Some(1)));

        // Bare month abbrev at EOS
        let p = Parts::from_str("2024 Mar").unwrap();
        assert_eq!((p.mo, p.day), (Some(3), Some(1)));

        // Explicit zero fields → default 1
        let p = Parts::from_str("2024-00").unwrap();
        assert_eq!((p.mo, p.day), (Some(1), Some(1)));
        let p = Parts::from_str("2024-03-0").unwrap();
        assert_eq!((p.mo, p.day), (Some(3), Some(1)));

        // Year-month + time (T is not the day)
        let p = Parts::from_str("2024-03T12:00").unwrap();
        assert_eq!((p.mo, p.day, p.hr, p.min), (Some(3), Some(1), 12, 0));

        // Year + time
        let p = Parts::from_str("2024T12:00").unwrap();
        assert_eq!((p.mo, p.day, p.hr), (Some(1), Some(1), 12));

        // to_dt works on partials
        assert!(Parts::from_str("2024-06").unwrap().to_dt().is_ok());
    }

    #[test]
    fn test_iso_week_date() {
        // Extended / basic week only (calendar yr cleared; ISO week year set)
        let p = Parts::from_str("2024-W11").unwrap();
        assert_eq!(p.yr, None);
        assert_eq!(p.iso_wk_yr, Some(2024));
        assert_eq!(p.iso_wk, Some(11));
        assert_eq!(p.wkday, None);
        assert!(p.to_dt().is_ok());

        let p = Parts::from_str("2024W11").unwrap();
        assert_eq!((p.iso_wk_yr, p.iso_wk), (Some(2024), Some(11)));

        // Optional weekday Mon=1…Sun=7
        let p = Parts::from_str("2024-W11-4").unwrap();
        assert_eq!(p.iso_wk, Some(11));
        assert_eq!(p.wkday, Some(Weekday::Thursday));

        let p = Parts::from_str("2024W114").unwrap();
        assert_eq!((p.iso_wk, p.wkday), (Some(11), Some(Weekday::Thursday)));

        // Valid basic weekday 7 (Sunday); invalid trailing digits must not become hours.
        let p = Parts::from_str("2024W117").unwrap();
        assert_eq!(
            (p.iso_wk, p.wkday, p.hr),
            (Some(11), Some(Weekday::Sunday), 0)
        );
        for s in [
            "2024W110",
            "2024W118",
            "2024W119",
            "2024-W11-0",
            "2024-W11-8",
        ] {
            assert!(
                matches!(
                    Parts::from_str(s).unwrap_err().kind(),
                    DtErrKind::ExpectedWeekdayNumber
                ),
                "{s:?}"
            );
        }

        // Time after week date (non-digit after week — not a weekday field)
        let p = Parts::from_str("2024-W11-4T12:30:00").unwrap();
        assert_eq!((p.hr, p.min, p.sec), (12, 30, 0));
        let p = Parts::from_str("2024W11T12:00").unwrap();
        assert_eq!((p.iso_wk, p.hr), (Some(11), 12));

        // W requires an immediate digit
        assert!(matches!(
            Parts::from_str("2024-W").unwrap_err().kind(),
            DtErrKind::ExpectedWeekNumber
        ));
        assert!(Parts::from_str("2024W").is_err());

        // Week 0 → 1
        let p = Parts::from_str("2024-W0").unwrap();
        assert_eq!(p.iso_wk, Some(1));
    }

    #[test]
    fn test_iso_flexible_time_components() {
        // 1-digit hour when next is punct/ws
        let p = Parts::from_str("2024-04-18T9:30:00").unwrap();
        assert_eq!((p.hr, p.min, p.sec), (9, 30, 0));

        // 1-digit minute then seconds
        let p = Parts::from_str("2024-04-18T14:3:25").unwrap();
        assert_eq!((p.hr, p.min, p.sec), (14, 3, 25));

        // 1-digit second + fraction
        let p = Parts::from_str("2024-04-18T14:30:5.5").unwrap();
        assert_eq!(p.sec, 5);
        assert_eq!(p.attos, 500_000_000_000_000_000);

        // Compact HHMMSS (no separators)
        let p = Parts::from_str("2024-04-18T143025").unwrap();
        assert_eq!((p.hr, p.min, p.sec), (14, 30, 25));

        // Space-separated time
        let p = Parts::from_str("2024-04-18T9 30").unwrap();
        assert_eq!((p.hr, p.min), (9, 30));

        // `.` is only for fractional seconds after a seconds field — not an H/M separator.
        for s in [
            "2024-04-18T12.5",
            "2024-04-18T12:30.5",
            "2024-04-18T12:3.5",
            "2024-04-18T12:.5",
            "2024-04-18T12:30:.5",
        ] {
            let err = Parts::from_str(s).unwrap_err();
            assert!(
                matches!(err.kind(), DtErrKind::ExpectedSecond),
                "{s:?}: {:?}",
                err.kind()
            );
        }
        // Still fine: seconds present, then fraction.
        let p = Parts::from_str("2024-04-18T12:30:25.5").unwrap();
        assert_eq!((p.hr, p.min, p.sec), (12, 30, 25));
        assert_eq!(p.attos, 500_000_000_000_000_000);
    }

    #[test]
    fn test_iso_space_padded_doy() {
        let p = Parts::from_str("2024-  9").unwrap();
        assert_eq!(p.day_of_yr, Some(9));
        assert_eq!(p.mo, None);

        let p = Parts::from_str("2024- 01").unwrap();
        assert_eq!(p.day_of_yr, Some(1));

        // Four digits after year sep → calendar, not DOY
        let p = Parts::from_str("2024-0401").unwrap();
        assert_eq!((p.mo, p.day, p.day_of_yr), (Some(4), Some(1), None));
    }

    #[test]
    fn test_iso_year_overflow() {
        let err = Parts::from_str("999999999999999999999-01-01").unwrap_err();
        assert!(matches!(err.kind(), DtErrKind::YearOutOfRange));

        let err = Parts::from_str("9223372036854775808-01-01").unwrap_err();
        assert!(matches!(err.kind(), DtErrKind::YearOutOfRange));
    }

    #[test]
    fn test_iso_numeric_overflow_no_panic() {
        // Integer accumulation boundary (u64::MAX + 1) used to panic in debug.
        let max = u64::MAX.to_string();
        let max_p1 = format!("{}", u64::MAX as u128 + 1);

        let p = Parts::from_str(&format!("SEC {max}")).unwrap();
        assert_eq!(
            p.timestamp.as_ref().map(|t| t.attos),
            Some((u64::MAX as i128) * deep_time::consts::ATTOS_PER_SEC_I128)
        );

        // Saturates integer part to u64::MAX — same attos as MAX itself.
        let p_sat = Parts::from_str(&format!("SEC {max_p1}")).unwrap();
        assert_eq!(
            p.timestamp.as_ref().map(|t| t.attos),
            p_sat.timestamp.as_ref().map(|t| t.attos)
        );

        // JD/MJD day×attos used to panic for huge day counts; saturates near i128 bounds.
        for s in [
            format!("JD {max}"),
            format!("JD {max_p1}"),
            format!("MJD {max}"),
            format!("MJD {max_p1}"),
            "JD 1000000000000000000".into(),
        ] {
            let p = Parts::from_str(&s).unwrap();
            let attos = p.timestamp.as_ref().unwrap().attos;
            assert!(attos > 0, "{s}: {attos}");
            // After saturating day×ATTOS_PER_DAY, epoch subtract leaves a value near MAX.
            assert!(attos > i128::MAX / 2, "{s}: {attos}");
        }

        let p = Parts::from_str(&format!("JD -{max}")).unwrap();
        assert!(p.timestamp.as_ref().unwrap().attos < 0);

        assert!(Parts::from_str_sec_f(&max_p1, None).is_some());
        assert!(Parts::from_str_jd_f(&max, None).is_some());
        assert!(Parts::from_str_mjd_f(&max_p1, None).is_some());
    }

    fn test_iso_sec_prefix() {
        // TAI case (exact integer + frac)
        let p = Parts::from_str("SEC 1234.567").unwrap();
        let dt = p.to_dt().unwrap();
        assert_eq!(dt.target, Scale::TAI);
        assert_eq!(dt.to_sec64_floor(), 1234);
        assert_eq!(dt.to_sec_ufrac(), 567_000_000_000_000_000);

        // lowercase + explicit TAI
        let p = Parts::from_str("sec1234.5 TAI").unwrap();
        let dt = p.to_dt().unwrap();
        assert_eq!(dt.target, Scale::TAI);
        assert_eq!(dt.to_sec64_floor(), 1234);
        assert_eq!(dt.to_sec_ufrac(), 500_000_000_000_000_000);

        // "SEC 0 TDB" must equal the TDB epoch
        let tdb_epoch = Dt::from_ymd(2000, 1, 1, Scale::TDB, 12, 0, 0, 0);
        let p = Parts::from_str("SEC 0 TDB").unwrap();
        let parsed = p.to_dt().unwrap();
        assert_eq!(parsed, tdb_epoch);

        // Non-zero TDB: build expected using exact raw attos + from_attos (avoids f64)
        let raw = 1234i128 * ATTOS_PER_SEC_I128 + 567_000_000_000_000_000;
        let expected_tdb = Dt::new(raw, Scale::TDB, Scale::TDB).to_tai();
        let p = Parts::from_str("SEC 1234.567 TDB").unwrap();
        let parsed = p.to_dt().unwrap();
        assert_eq!(parsed, expected_tdb);

        // Same for GPS
        let raw_gps = 42i128 * ATTOS_PER_SEC_I128 + 750_000_000_000_000_000;
        let expected_gps = Dt::new(raw_gps, Scale::GPS, Scale::GPS).to_tai();
        let p = Parts::from_str("Sec 42.75 GPS").unwrap();
        let parsed = p.to_dt().unwrap();
        assert_eq!(parsed, expected_gps);
    }

    #[test]
    fn test_iso_jd_prefix() {
        // J2000.0 noon (JD 2451545.0) on TAI — this is the library epoch (attos == 0)
        let expected = Dt::from_jd_f(2_451_545.0, Scale::TAI);
        let p = Parts::from_str("JD 2451545.0 TAI").unwrap();
        assert_eq!(p.to_dt().unwrap(), expected);
        let d = Dt::from_str("JD 2451545.0 TAI").unwrap();
        assert_eq!(d, expected);
        assert_eq!(d.to_attos(), 0);

        // Positive fractional JD, no explicit scale (defaults to TAI inside parser)
        let expected = Dt::from_jd_f(2_451_545.5, Scale::TAI);
        let d = Dt::from_str("jd 2451545.5").unwrap();
        assert_eq!(d, expected);

        // No space after prefix, different scale
        let expected = Dt::from_jd_f(2_451_545.25, Scale::TT);
        let p = Parts::from_str("JD2451545.25 TT").unwrap();
        assert_eq!(p.scale, Scale::TT);
        assert_eq!(p.to_dt().unwrap(), expected);

        // Positive with scale and junk before (the JD detector still triggers)
        let expected = Dt::from_jd_f(2_460_000.75, Scale::GPS);
        let d = Dt::from_str("  jd = 2460000.75 GPS").unwrap();
        assert_eq!(d, expected);
        assert_eq!(d.target, Scale::GPS);

        // Negative JD values
        let expected = Dt::from_jd_f(-2_451_545.0, Scale::TAI);
        let p = Parts::from_str("JD -2451545.0 TAI").unwrap();
        assert_eq!(p.to_dt().unwrap(), expected);

        let expected = Dt::from_jd_f(-1_000.5, Scale::UTC);
        let d = Dt::from_str("prefix: prefix.. JD -1000.5 UTC").unwrap();
        assert_eq!(d, expected);
    }

    #[test]
    fn test_iso_mjd_prefix() {
        // J2000.0 as MJD 51544.5
        let expected = Dt::from_mjd_f(51_544.5, Scale::TAI);
        let p = Parts::from_str("MJD 51544.5 TAI").unwrap();
        assert_eq!(p.to_dt().unwrap(), expected);
        let d = Dt::from_str("junk MJD 51544.5 TAI").unwrap();
        assert_eq!(d, expected);

        // Positive fractional MJD, implicit scale
        let expected = Dt::from_mjd_f(51_544.25, Scale::TAI);
        let d = Dt::from_str("mjd 51544.25").unwrap();
        assert_eq!(d, expected);

        // Mixed case, no space, explicit scale
        let expected = Dt::from_mjd_f(60_000.75, Scale::TDB);
        let p = Parts::from_str("Mjd60000.75 TDB").unwrap();
        assert_eq!(p.scale, Scale::TDB);
        assert_eq!(p.to_dt().unwrap(), expected);

        // Negative MJD
        let expected = Dt::from_mjd_f(-10_000.0, Scale::GPS);
        let d = Dt::from_str("MJD -10000 GPS").unwrap();
        assert_eq!(d, expected);
        assert_eq!(d.target, Scale::GPS);

        let expected = Dt::from_mjd_f(-51_544.5, Scale::UTC);
        let p = Parts::from_str("  mjd=-51544.5 UTC  ").unwrap();
        assert_eq!(p.to_dt().unwrap(), expected);
    }

    #[test]
    fn test_iso_abbrev_month_name() {
        let tp = Parts::from_str("2024 Apr 18, 14:30:25 [America/New_York]").unwrap();
        assert_eq!(tp.yr, Some(2024));
        assert_eq!(tp.mo, Some(4));
        assert_eq!(tp.day, Some(18));
        assert_eq!(tp.hr, 14);
        assert_eq!(tp.min, 30);
        assert_eq!(tp.sec, 25);
        assert_eq!(tp.offset, None);
        assert!(tp.iana_name.is_some());
    }

    #[test]
    fn test_iso_weekday_first_day_month_year() {
        // RFC 2822 / HTTP-date style: weekday, day month year time
        let tp = Parts::from_str("Sat, 07 Feb 2015 11:22:33").unwrap();
        assert_eq!(tp.wkday, Some(Weekday::Saturday));
        assert_eq!(tp.day, Some(7));
        assert_eq!(tp.mo, Some(2));
        assert_eq!(tp.yr, Some(2015));
        assert_eq!((tp.hr, tp.min, tp.sec), (11, 22, 33));

        // Full weekday name (matched on first three letters)
        let tp = Parts::from_str("Saturday, 7 February 2015 11:22:33").unwrap();
        assert_eq!(tp.wkday, Some(Weekday::Saturday));
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(7), Some(2), Some(2015)));
        assert_eq!((tp.hr, tp.min, tp.sec), (11, 22, 33));

        // Case-insensitive abbrev, no comma
        let tp = Parts::from_str("mon 1 jan 2000").unwrap();
        assert_eq!(tp.wkday, Some(Weekday::Monday));
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(1), Some(1), Some(2000)));

        // Numeric month also accepted in day-first order
        let tp = Parts::from_str("Wed, 16/04/2025 14:30:45").unwrap();
        assert_eq!(tp.wkday, Some(Weekday::Wednesday));
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(16), Some(4), Some(2025)));
        assert_eq!((tp.hr, tp.min, tp.sec), (14, 30, 45));

        // Hyphen separators must not be read as a negative year (`dd-mmm-yyyy`, `dd-mm-yyyy`)
        let tp = Parts::from_str("Sat, 07-Feb-2015 11:22:33").unwrap();
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(7), Some(2), Some(2015)));
        assert_eq!((tp.hr, tp.min, tp.sec), (11, 22, 33));
        let tp = Parts::from_str("Sat, 07-02-2015").unwrap();
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(7), Some(2), Some(2015)));
        let tp = Parts::from_str("Sat, 07 Feb-2015 11:22:33").unwrap();
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(7), Some(2), Some(2015)));

        // Explicit signed years: space before sign, or doubled separator
        let tp = Parts::from_str("Sat, 07 Feb -4714 12:00:00").unwrap();
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(7), Some(2), Some(-4714)));
        assert_eq!((tp.hr, tp.min), (12, 0));
        let tp = Parts::from_str("Sat, 07 Feb +0042 11:22:33").unwrap();
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(7), Some(2), Some(42)));
        let tp = Parts::from_str("Sat, 07-Feb--4714").unwrap();
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(7), Some(2), Some(-4714)));

        // Offset after a normal year still works
        let tp = Parts::from_str("Sat, 07 Feb 2015 -0500").unwrap();
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(7), Some(2), Some(2015)));
        assert_eq!(tp.offset, Some(Offset::Fixed(-5 * 3600)));

        // Junk before weekday still selects day-first
        let tp = Parts::from_str("Date: Fri, 18 Apr 2024").unwrap();
        assert_eq!(tp.wkday, Some(Weekday::Friday));
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(18), Some(4), Some(2024)));

        // Date only (no time)
        let tp = Parts::from_str("Thu 25 Dec 2025").unwrap();
        assert_eq!(tp.wkday, Some(Weekday::Thursday));
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(25), Some(12), Some(2025)));
        assert_eq!((tp.hr, tp.min, tp.sec), (0, 0, 0));

        // Compact / glued forms (minimal or no separators)
        let compact = [
            "Sat,07Feb2015T11:22:33",
            "Sat,07Feb2015 11:22:33",
            "Sat07Feb2015T11:22:33",
            "Sat,7Feb2015T11:22:33",
            "Sat,07Feb2015T112233",
            "Sat,07February2015T11:22:33",
            "Sat,07-Feb-2015T11:22:33",
            "Sat,07/02/2015T11:22:33",
            "Sat,07022015T11:22:33",
        ];
        for s in compact {
            let tp = Parts::from_str(s).unwrap_or_else(|e| panic!("{s:?}: {e:?}"));
            assert_eq!(tp.wkday, Some(Weekday::Saturday), "{s}");
            assert_eq!(
                (tp.day, tp.mo, tp.yr),
                (Some(7), Some(2), Some(2015)),
                "{s}"
            );
            assert_eq!((tp.hr, tp.min, tp.sec), (11, 22, 33), "{s}");
        }
        // Fully glued, date only
        let tp = Parts::from_str("mon1jan2000").unwrap();
        assert_eq!(tp.wkday, Some(Weekday::Monday));
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(1), Some(1), Some(2000)));
        assert_eq!((tp.hr, tp.min, tp.sec), (0, 0, 0));
        let tp = Parts::from_str("Sat,07Feb2015").unwrap();
        assert_eq!((tp.day, tp.mo, tp.yr), (Some(7), Some(2), Some(2015)));

        // Year-first still works when no leading weekday
        let tp = Parts::from_str("2015-02-07 11:22:33").unwrap();
        assert_eq!(tp.wkday, None);
        assert_eq!((tp.yr, tp.mo, tp.day), (Some(2015), Some(2), Some(7)));

        // Weekday without a following day → error
        assert!(matches!(
            Parts::from_str("Saturday").unwrap_err().kind(),
            DtErrKind::ExpectedDay
        ));
        // Weekday + day but no month
        assert!(matches!(
            Parts::from_str("Sat 07").unwrap_err().kind(),
            DtErrKind::ExpectedMonth
        ));
        // Weekday + day + month but no year
        assert!(matches!(
            Parts::from_str("Sat 07 Feb").unwrap_err().kind(),
            DtErrKind::ExpectedYear
        ));
    }

    #[test]
    fn test_iso_full_month_name() {
        let tp = Parts::from_str("2024 September 18, 14:30:25 [America/New_York]").unwrap();
        assert_eq!(tp.yr, Some(2024));
        assert_eq!(tp.mo, Some(9));
        assert_eq!(tp.day, Some(18));
        assert_eq!(tp.hr, 14);
        assert_eq!(tp.min, 30);
        assert_eq!(tp.sec, 25);
        assert_eq!(tp.offset, None);
        assert!(tp.iana_name.is_some());
    }

    #[test]
    fn test_iso_spice() {
        let tp = Parts::from_str("1997-162::12:18:28").unwrap();
        assert_eq!(tp.yr, Some(1997));
        assert_eq!(tp.day_of_yr, Some(162));
        assert_eq!(tp.hr, 12);
        assert_eq!(tp.min, 18);
        assert_eq!(tp.sec, 28);
        assert_eq!(tp.offset, None);
    }

    #[cfg(any(feature = "jiff-tz-bundle", feature = "jiff-tz"))]
    #[test]
    fn test_iso_doy() {
        let tp = Parts::from_str("2024-109 14:30:25.123 [America/New_York]").unwrap();
        assert_eq!(tp.yr, Some(2024));
        assert_eq!(tp.day_of_yr, Some(109));
        assert_eq!(tp.hr, 14);
        assert_eq!(tp.min, 30);
        assert_eq!(tp.sec, 25);
        assert_eq!(tp.offset, None);
        assert_eq!(tp.iana_name.as_ref().unwrap().as_str(), "America/New_York");
        let ymd = &tp.to_dt().unwrap().to_ymd();
        assert_eq!(ymd.yr(), 2024);
        assert_eq!(ymd.mo(), 4);
        assert_eq!(ymd.day(), 18);
        assert_eq!(ymd.hr(), 18);
        assert_eq!(ymd.min(), 30);
        assert_eq!(ymd.sec(), 25);
        assert_eq!(as_ms!(ymd.attos() as i128), 123);
    }
}