vct-core 2.3.1

//! Timestamp parsing helpers for the ISO-8601 / RFC 3339 strings that the
//! provider session logs embed in each record.

use chrono::{DateTime, SecondsFormat, Utc};

/// Current UTC time as RFC3339 with nanoseconds and a `Z` suffix
/// (e.g. `2026-07-07T05:34:50.563606999Z`).
///
/// Matches the format Codex writes for `auth.json`'s `last_refresh` and the
/// stamp the quota version caches / self `version.json` record use.
pub fn now_rfc3339_utc_nanos() -> String {
    Utc::now().to_rfc3339_opts(SecondsFormat::Nanos, true)
}

/// Formats `unix_secs` in the same shape [`now_rfc3339_utc_nanos`] produces.
///
/// Used to stamp a refreshed token's expiry in the exact format the Grok CLI
/// writes into `auth.json`. Returns `None` for a timestamp outside the
/// representable range rather than silently substituting another instant.
pub fn rfc3339_utc_nanos(unix_secs: i64) -> Option<String> {
    DateTime::from_timestamp(unix_secs, 0).map(|dt| dt.to_rfc3339_opts(SecondsFormat::Nanos, true))
}

/// Parses an ISO-8601 / RFC 3339 timestamp into Unix milliseconds.
///
/// RFC 3339 is tried first (the common case, with timezone offset or `Z`),
/// then a small set of explicit UTC fallback patterns covering 3-digit,
/// arbitrary-precision, and zero-fraction sub-seconds. Surrounding
/// whitespace is *not* tolerated.
///
/// Returns `0` for an empty string or any input that matches none of the
/// accepted formats; callers treat `0` as "unknown time" rather than the
/// Unix epoch.
///
/// # Examples
///
/// ```
/// use vct_core::utils::parse_iso_timestamp;
///
/// assert_eq!(parse_iso_timestamp("1970-01-01T00:00:01Z"), 1_000);
/// assert_eq!(parse_iso_timestamp(""), 0);
/// assert_eq!(parse_iso_timestamp("not a timestamp"), 0);
/// ```
pub fn parse_iso_timestamp(ts: &str) -> i64 {
    if ts.is_empty() {
        return 0;
    }

    // Try RFC3339 first (most common format)
    if let Ok(dt) = DateTime::parse_from_rfc3339(ts) {
        return dt.timestamp_millis();
    }

    // Try other formats
    let formats = [
        "%Y-%m-%dT%H:%M:%S%.3fZ",
        "%Y-%m-%dT%H:%M:%S%.fZ",
        "%Y-%m-%dT%H:%M:%SZ",
    ];

    for format in &formats {
        if let Ok(dt) = DateTime::parse_from_str(ts, format) {
            return dt.timestamp_millis();
        }
    }

    0
}

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

    #[test]
    fn rfc3339_utc_nanos_round_trips_and_matches_the_now_shape() {
        let stamp = rfc3339_utc_nanos(1_785_058_368).expect("in range");
        assert_eq!(stamp, "2026-07-26T09:32:48.000000000Z");
        // The same shape `now_rfc3339_utc_nanos` writes, and re-readable.
        assert_eq!(parse_iso_timestamp(&stamp), 1_785_058_368_000);
        assert_eq!(
            stamp.len(),
            now_rfc3339_utc_nanos().len(),
            "both stamps must be the fixed-width nanosecond form"
        );
        // Out of range yields None rather than a substituted instant.
        assert!(rfc3339_utc_nanos(i64::MAX).is_none());
    }

    #[test]
    fn test_parse_iso_timestamp_rfc3339() {
        // Test parsing RFC3339 format (most common)
        let ts = "2024-01-15T10:30:45.123Z";
        let result = parse_iso_timestamp(ts);
        assert!(result > 0);

        // Should parse to a valid timestamp (2024)
        assert!(result > 1_700_000_000_000); // After 2023
        assert!(result < 1_800_000_000_000); // Before 2027
    }

    #[test]
    fn test_parse_iso_timestamp_with_timezone() {
        // Test parsing with timezone offset
        let ts = "2024-01-15T10:30:45.123+08:00";
        let result = parse_iso_timestamp(ts);
        assert!(result > 0);
    }

    #[test]
    fn test_parse_iso_timestamp_no_millis() {
        // Test parsing without milliseconds
        let ts = "2024-01-15T10:30:45Z";
        let result = parse_iso_timestamp(ts);
        assert!(result > 0);
    }

    #[test]
    fn test_parse_iso_timestamp_fallback_formats() {
        // Test fallback format with milliseconds
        let ts1 = "2024-01-15T10:30:45.123Z";
        let result1 = parse_iso_timestamp(ts1);
        assert!(result1 > 0);

        // Test fallback format with fractional seconds
        let ts2 = "2024-01-15T10:30:45.123456Z";
        let result2 = parse_iso_timestamp(ts2);
        assert!(result2 > 0);

        // Test fallback format without fractional seconds
        let ts3 = "2024-01-15T10:30:45Z";
        let result3 = parse_iso_timestamp(ts3);
        assert!(result3 > 0);
    }

    #[test]
    fn test_parse_iso_timestamp_empty() {
        // Test parsing empty string
        let result = parse_iso_timestamp("");
        assert_eq!(result, 0);
    }

    #[test]
    fn test_parse_iso_timestamp_invalid() {
        // Test parsing invalid format
        let result = parse_iso_timestamp("not a timestamp");
        assert_eq!(result, 0);

        let result = parse_iso_timestamp("2024-13-45");
        assert_eq!(result, 0);

        let result = parse_iso_timestamp("invalid-date-time");
        assert_eq!(result, 0);
    }

    #[test]
    fn test_parse_iso_timestamp_different_years() {
        // Test different years to ensure parsing is consistent
        let ts_2020 = "2020-06-15T12:00:00Z";
        let ts_2024 = "2024-06-15T12:00:00Z";

        let result_2020 = parse_iso_timestamp(ts_2020);
        let result_2024 = parse_iso_timestamp(ts_2024);

        assert!(result_2020 > 0);
        assert!(result_2024 > 0);
        assert!(result_2024 > result_2020);
    }

    #[test]
    fn test_parse_iso_timestamp_milliseconds_precision() {
        // Test that milliseconds are preserved
        let ts1 = "2024-01-15T10:30:45.000Z";
        let ts2 = "2024-01-15T10:30:45.999Z";

        let result1 = parse_iso_timestamp(ts1);
        let result2 = parse_iso_timestamp(ts2);

        assert!(result1 > 0);
        assert!(result2 > 0);
        // Should be ~999ms apart
        assert!(result2 > result1);
        assert!(result2 - result1 < 1000);
    }

    #[test]
    fn test_parse_iso_timestamp_same_time() {
        // Test parsing the same timestamp twice
        let ts = "2024-01-15T10:30:45.123Z";
        let result1 = parse_iso_timestamp(ts);
        let result2 = parse_iso_timestamp(ts);

        assert_eq!(result1, result2);
    }

    #[test]
    fn test_parse_iso_timestamp_edge_cases() {
        // Test edge cases

        // Beginning of year
        let ts1 = "2024-01-01T00:00:00Z";
        let result1 = parse_iso_timestamp(ts1);
        assert!(result1 > 0);

        // End of year
        let ts2 = "2024-12-31T23:59:59Z";
        let result2 = parse_iso_timestamp(ts2);
        assert!(result2 > 0);
        assert!(result2 > result1);

        // Leap year day
        let ts3 = "2024-02-29T12:00:00Z";
        let result3 = parse_iso_timestamp(ts3);
        assert!(result3 > 0);
    }

    #[test]
    fn test_parse_iso_timestamp_negative_timezone() {
        // Test parsing with negative timezone offset
        let ts = "2024-01-15T10:30:45.123-05:00";
        let result = parse_iso_timestamp(ts);
        assert!(result > 0);
    }

    #[test]
    fn test_parse_iso_timestamp_midnight() {
        // Test midnight timestamps
        let ts = "2024-01-15T00:00:00.000Z";
        let result = parse_iso_timestamp(ts);
        assert!(result > 0);
    }

    #[test]
    fn test_parse_iso_timestamp_noon() {
        // Test noon timestamps
        let ts = "2024-01-15T12:00:00.000Z";
        let result = parse_iso_timestamp(ts);
        assert!(result > 0);
    }

    #[test]
    fn test_parse_iso_timestamp_whitespace() {
        // Test that whitespace is not tolerated
        let result = parse_iso_timestamp(" 2024-01-15T10:30:45Z ");
        assert_eq!(result, 0);
    }

    #[test]
    fn test_parse_iso_timestamp_partial() {
        // Test partial timestamps (invalid)
        let result = parse_iso_timestamp("2024-01-15");
        assert_eq!(result, 0);

        let result = parse_iso_timestamp("2024-01-15T10:30");
        assert_eq!(result, 0);
    }

    #[test]
    fn test_parse_iso_timestamp_ordering() {
        // Test that timestamps maintain proper ordering
        let timestamps = [
            "2024-01-15T10:00:00Z",
            "2024-01-15T11:00:00Z",
            "2024-01-15T12:00:00Z",
            "2024-01-15T13:00:00Z",
        ];

        let results: Vec<i64> = timestamps
            .iter()
            .map(|ts| parse_iso_timestamp(ts))
            .collect();

        // All should be non-zero
        assert!(results.iter().all(|&r| r > 0));

        // Should be in ascending order
        for i in 1..results.len() {
            assert!(results[i] > results[i - 1]);
        }
    }
}