Function parse_iso_datetime

graphlite/src/functions/temporal_functions.rs:1045–1076

Parse ISO 8601 datetime string into DateTime Supports formats like: - 2024-01-15T10:30:45Z - 2024-01-15T10:30:45.123Z - 2024-01-15T10:30:45+00:00 - 2024-01-15T10:30:45.123+00:00

(datetime_str: &str)

/// - 2024-01-15T10:30:45+00:00
/// - 2024-01-15T10:30:45.123+00:00
fn parse_iso_datetime(datetime_str: &str) -> Result<DateTime<Utc>, String> {
    // Try different ISO 8601 formats
    let formats = [
        "%Y-%m-%dT%H:%M:%SZ",      // 2024-01-15T10:30:45Z
        "%Y-%m-%dT%H:%M:%S%.3fZ",  // 2024-01-15T10:30:45.123Z
        "%Y-%m-%dT%H:%M:%S%z",     // 2024-01-15T10:30:45+00:00
        "%Y-%m-%dT%H:%M:%S%.3f%z", // 2024-01-15T10:30:45.123+00:00
        "%Y-%m-%dT%H:%M:%S",       // 2024-01-15T10:30:45 (assume UTC)
    ];

    // First try chrono's built-in RFC 3339 parser (most robust)
    if let Ok(datetime) = DateTime::parse_from_rfc3339(datetime_str) {
        return Ok(datetime.with_timezone(&Utc));
    }

    // Try manual parsing with different formats
    for format in &formats {
        if let Ok(datetime) = DateTime::parse_from_str(datetime_str, format) {
            return Ok(datetime.with_timezone(&Utc));
        }
    }

    // Try parsing as naive datetime and assume UTC
    if let Ok(naive_dt) = chrono::NaiveDateTime::parse_from_str(datetime_str, "%Y-%m-%dT%H:%M:%S") {
        return Ok(DateTime::from_naive_utc_and_offset(naive_dt, Utc));
    }

    Err(format!(
        "Unable to parse datetime '{}' - expected ISO 8601 format",
        datetime_str
    ))
}

/// Parse ISO 8601 duration string into total seconds
///