Function parse_timezone

graphlite/src/functions/timezone_functions.rs:19–57

Parse timezone string into either a named timezone or fixed offset

(tz_str: &str)

/// Parse timezone string into either a named timezone or fixed offset
fn parse_timezone(tz_str: &str) -> Result<TimezoneType, String> {
    // Try parsing as named timezone first
    if let Ok(tz) = tz_str.parse::<Tz>() {
        return Ok(TimezoneType::Named(tz));
    }

    // Try common timezone abbreviations
    let canonical_tz = match tz_str.to_uppercase().as_str() {
        "UTC" | "GMT" => "UTC",
        "EST" => "America/New_York",    // Eastern Standard Time
        "EDT" => "America/New_York",    // Eastern Daylight Time
        "CST" => "America/Chicago",     // Central Standard Time
        "CDT" => "America/Chicago",     // Central Daylight Time
        "MST" => "America/Denver",      // Mountain Standard Time
        "MDT" => "America/Denver",      // Mountain Daylight Time
        "PST" => "America/Los_Angeles", // Pacific Standard Time
        "PDT" => "America/Los_Angeles", // Pacific Daylight Time
        "BST" => "Europe/London",       // British Summer Time
        "CET" => "Europe/Paris",        // Central European Time
        "CEST" => "Europe/Paris",       // Central European Summer Time
        "JST" => "Asia/Tokyo",          // Japan Standard Time
        "IST" => "Asia/Kolkata",        // India Standard Time
        "AEST" => "Australia/Sydney",   // Australian Eastern Standard Time
        "AEDT" => "Australia/Sydney",   // Australian Eastern Daylight Time
        _ => tz_str,                    // Use original if no abbreviation match
    };

    // Try parsing the canonical timezone name
    if let Ok(tz) = canonical_tz.parse::<Tz>() {
        return Ok(TimezoneType::Named(tz));
    }

    // Try parsing as fixed offset (+05:30, -04:00, etc.)
    if let Ok(offset) = parse_fixed_offset(tz_str) {
        return Ok(TimezoneType::Fixed(offset));
    }

    Err(format!("Invalid timezone: {}", tz_str))
}

/// Parse fixed offset strings like "+05:30", "-04:00", "+0530", "-0400"
fn parse_fixed_offset(offset_str: &str) -> Result<FixedOffset, String> {