uni-query 1.1.0

// SPDX-License-Identifier: Apache-2.0
// Copyright 2024-2026 Dragonscale Team

//! Temporal functions for Cypher query evaluation.
//!
//! Provides date, time, datetime, and duration constructors along with
//! extraction functions compatible with OpenCypher temporal types.

use anyhow::{Result, anyhow};
use chrono::{
    DateTime, Datelike, Duration, FixedOffset, NaiveDate, NaiveDateTime, NaiveTime, Offset,
    TimeZone, Timelike, Utc, Weekday,
};
use chrono_tz::Tz;
use std::collections::HashMap;
// Re-export TemporalType so downstream modules (expr_eval, etc.) that import from
// `crate::query::datetime::TemporalType` continue to work.
pub use uni_common::TemporalType;
use uni_common::{TemporalValue, Value};

// ============================================================================
// Constants
// ============================================================================

const MICROS_PER_SECOND: i64 = 1_000_000;
const MICROS_PER_MINUTE: i64 = 60 * MICROS_PER_SECOND;
const MICROS_PER_HOUR: i64 = 60 * MICROS_PER_MINUTE;
const MICROS_PER_DAY: i64 = 24 * MICROS_PER_HOUR;
const SECONDS_PER_DAY: i64 = 86_400;
const NANOS_PER_SECOND: i64 = 1_000_000_000;
const NANOS_PER_DAY: i64 = 24 * 3600 * NANOS_PER_SECOND;

/// Classify a string value into its temporal type using pattern detection.
pub fn classify_temporal(s: &str) -> Option<TemporalType> {
    // Strip bracketed timezone suffix for classification
    let base = if let Some(bracket_pos) = s.find('[') {
        &s[..bracket_pos]
    } else {
        s
    };

    // Duration: starts with P (case insensitive)
    if base.starts_with(['P', 'p']) {
        return Some(TemporalType::Duration);
    }

    // Check for date component (YYYY-MM-DD pattern)
    let has_date = base.len() >= 10
        && base.as_bytes().get(4) == Some(&b'-')
        && base.as_bytes().get(7) == Some(&b'-')
        && base[..4].bytes().all(|b| b.is_ascii_digit())
        && base[5..7].bytes().all(|b| b.is_ascii_digit())
        && base[8..10].bytes().all(|b| b.is_ascii_digit());

    // Check for T separator indicating datetime
    let has_t = has_date && base.len() > 10 && base.as_bytes().get(10) == Some(&b'T');

    if has_date && has_t {
        // Has both date and time components
        let after_t = &base[11..];
        if has_timezone_suffix(after_t) {
            Some(TemporalType::DateTime)
        } else {
            Some(TemporalType::LocalDateTime)
        }
    } else if has_date {
        Some(TemporalType::Date)
    } else {
        // Try time patterns: HH:MM:SS or HH:MM:SS.fff
        let has_time = base.len() >= 5
            && base.as_bytes().get(2) == Some(&b':')
            && base[..2].bytes().all(|b| b.is_ascii_digit())
            && base[3..5].bytes().all(|b| b.is_ascii_digit());

        if has_time {
            if has_timezone_suffix(base) {
                Some(TemporalType::Time)
            } else {
                Some(TemporalType::LocalTime)
            }
        } else {
            None
        }
    }
}

/// Check if a temporal string suffix contains timezone information.
fn has_timezone_suffix(s: &str) -> bool {
    if s.ends_with(['Z', 'z']) {
        return true;
    }
    // Look for +HH:MM or -HH:MM at the end, accounting for possible [timezone]
    // Find last occurrence of + or - that could be a timezone offset
    for (i, b) in s.bytes().enumerate().rev() {
        if b == b'+' || b == b'-' {
            let after = &s[i + 1..];
            if after.len() >= 4
                && after[..2].bytes().all(|b| b.is_ascii_digit())
                && after.as_bytes().get(2) == Some(&b':')
            {
                return true;
            }
            // Could be +HHMM format
            if after.len() >= 4 && after[..4].bytes().all(|b| b.is_ascii_digit()) {
                return true;
            }
        }
    }
    false
}

/// Parse a duration from a Value, handling temporal durations, ISO 8601 strings, and integer microseconds.
pub fn parse_duration_from_value(val: &Value) -> Result<CypherDuration> {
    match val {
        Value::Temporal(TemporalValue::Duration {
            months,
            days,
            nanos,
        }) => Ok(CypherDuration::new(*months, *days, *nanos)),
        Value::Map(map) => {
            if let Some(Value::Map(inner)) = map.get("Duration")
                && let (Some(months), Some(days), Some(nanos)) = (
                    inner.get("months").and_then(Value::as_i64),
                    inner.get("days").and_then(Value::as_i64),
                    inner.get("nanos").and_then(Value::as_i64),
                )
            {
                return Ok(CypherDuration::new(months, days, nanos));
            }
            Err(anyhow!("Expected duration value"))
        }
        Value::String(s) => parse_duration_to_cypher(s),
        Value::Int(micros) => Ok(CypherDuration::from_micros(*micros)),
        _ => Err(anyhow!("Expected duration value")),
    }
}

// ============================================================================
// Timezone Handling
// ============================================================================

/// Parsed timezone information.
#[derive(Debug, Clone)]
pub enum TimezoneInfo {
    /// Fixed offset timezone (e.g., +01:00, -05:00, Z)
    FixedOffset(FixedOffset),
    /// Named IANA timezone (e.g., Europe/Stockholm)
    Named(Tz),
}

impl TimezoneInfo {
    /// Get the offset in seconds for a given local datetime.
    pub fn offset_for_local(&self, ndt: &NaiveDateTime) -> Result<FixedOffset> {
        match self {
            TimezoneInfo::FixedOffset(fo) => Ok(*fo),
            TimezoneInfo::Named(tz) => {
                // Get the offset for the given local time
                match tz.from_local_datetime(ndt) {
                    chrono::LocalResult::Single(dt) => Ok(dt.offset().fix()),
                    chrono::LocalResult::Ambiguous(dt1, _dt2) => {
                        // During DST transition, pick the earlier one (standard time)
                        Ok(dt1.offset().fix())
                    }
                    chrono::LocalResult::None => {
                        // Time doesn't exist (DST gap), find the closest valid time
                        Err(anyhow!("Local time does not exist in timezone (DST gap)"))
                    }
                }
            }
        }
    }

    /// Get the offset for a given UTC datetime (no ambiguity possible).
    pub fn offset_for_utc(&self, utc_ndt: &NaiveDateTime) -> FixedOffset {
        match self {
            TimezoneInfo::FixedOffset(fo) => *fo,
            TimezoneInfo::Named(tz) => tz.from_utc_datetime(utc_ndt).offset().fix(),
        }
    }

    /// Get the timezone name for output formatting.
    fn name(&self) -> Option<&str> {
        match self {
            TimezoneInfo::FixedOffset(_) => None,
            TimezoneInfo::Named(tz) => Some(tz.name()),
        }
    }

    /// Get offset seconds for a fixed offset timezone, or for a named timezone at a given date.
    fn offset_seconds_with_date(&self, date: &NaiveDate) -> i32 {
        match self {
            TimezoneInfo::FixedOffset(fo) => fo.local_minus_utc(),
            TimezoneInfo::Named(tz) => {
                // Use noon on the date to calculate offset (avoids DST transition edge cases)
                let noon = NaiveTime::from_hms_opt(12, 0, 0).unwrap();
                let ndt = NaiveDateTime::new(*date, noon);
                match tz.from_local_datetime(&ndt) {
                    chrono::LocalResult::Single(dt) => dt.offset().fix().local_minus_utc(),
                    chrono::LocalResult::Ambiguous(dt1, _) => dt1.offset().fix().local_minus_utc(),
                    chrono::LocalResult::None => 0, // Fallback, shouldn't happen at noon
                }
            }
        }
    }
}

/// Parse timezone - supports fixed offsets (+01:00) and IANA names (Europe/Stockholm).
fn parse_timezone(tz_str: &str) -> Result<TimezoneInfo> {
    let tz_str = tz_str.trim();

    // Try parsing as IANA timezone name first
    if let Ok(tz) = tz_str.parse::<Tz>() {
        return Ok(TimezoneInfo::Named(tz));
    }

    // Try parsing as fixed offset
    let offset_secs = parse_timezone_offset(tz_str)?;
    let offset = FixedOffset::east_opt(offset_secs)
        .ok_or_else(|| anyhow!("Invalid timezone offset: {}", offset_secs))?;
    Ok(TimezoneInfo::FixedOffset(offset))
}

// ============================================================================
// Public API
// ============================================================================

/// Parse a datetime string into a `DateTime<Utc>`.
///
/// Supports multiple formats:
/// - RFC3339 (e.g., "2023-01-01T00:00:00Z")
/// - "%Y-%m-%d %H:%M:%S %z" (e.g., "2023-01-01 00:00:00 +0000")
/// - "%Y-%m-%d %H:%M:%S" naive (assumed UTC)
///
/// This is the canonical datetime parsing function for temporal operations
/// like `validAt`. Using a single implementation ensures consistent behavior.
pub fn parse_datetime_utc(s: &str) -> Result<DateTime<Utc>> {
    // Temporal string renderings in the engine can include a bracketed timezone
    // suffix (e.g. "2020-01-01T00:00Z[UTC]"). Strip it for parsing while keeping
    // the explicit offset/UTC marker in the base datetime.
    let s = s.trim();
    let parse_input = match s.rfind('[') {
        Some(pos) if s.ends_with(']') => &s[..pos],
        _ => s,
    };

    DateTime::parse_from_rfc3339(parse_input)
        .map(|dt: DateTime<FixedOffset>| dt.with_timezone(&Utc))
        .or_else(|_| {
            // Handle formats without seconds (e.g., "2023-01-01T00:00Z")
            if let Some(base) = parse_input.strip_suffix('Z') {
                NaiveDateTime::parse_from_str(base, "%Y-%m-%dT%H:%M")
                    .map(|ndt| DateTime::<Utc>::from_naive_utc_and_offset(ndt, Utc))
            } else {
                // Handle formats without seconds with offset (e.g., "2023-01-01T00:00+05:00")
                DateTime::parse_from_str(parse_input, "%Y-%m-%dT%H:%M%:z")
                    .map(|dt: DateTime<FixedOffset>| dt.with_timezone(&Utc))
            }
        })
        .or_else(|_| {
            DateTime::parse_from_str(parse_input, "%Y-%m-%d %H:%M:%S %z")
                .map(|dt: DateTime<FixedOffset>| dt.with_timezone(&Utc))
        })
        .or_else(|_| {
            NaiveDateTime::parse_from_str(parse_input, "%Y-%m-%d %H:%M:%S")
                .map(|ndt| DateTime::<Utc>::from_naive_utc_and_offset(ndt, Utc))
        })
        .map_err(|_| anyhow!("Invalid datetime format: {}", s))
}

/// Evaluate a temporal function using a frozen statement clock.
///
/// Routes to the appropriate handler based on function name. Supports:
/// - Basic constructors: DATE, TIME, DATETIME, LOCALDATETIME, LOCALTIME, DURATION
/// - Extraction: YEAR, MONTH, DAY, HOUR, MINUTE, SECOND
/// - Dotted namespace functions: DATETIME.FROMEPOCH, DATE.TRUNCATE, etc.
///
/// For zero-arg temporal constructors (e.g. `time()`, `datetime()`), uses the
/// provided `frozen_now` instead of calling `Utc::now()`.  This ensures that
/// all occurrences within the same statement return an identical value, as
/// required by the OpenCypher specification.
pub fn eval_datetime_function_with_clock(
    name: &str,
    args: &[Value],
    frozen_now: chrono::DateTime<chrono::Utc>,
) -> Result<Value> {
    // Zero-arg temporal constructors use the frozen clock
    if args.is_empty() {
        match name {
            "DATE" | "DATE.STATEMENT" | "DATE.TRANSACTION" => {
                let d = frozen_now.date_naive();
                return Ok(Value::Temporal(TemporalValue::Date {
                    days_since_epoch: date_to_days_since_epoch(&d),
                }));
            }
            "TIME" | "TIME.STATEMENT" | "TIME.TRANSACTION" => {
                let t = frozen_now.time();
                return Ok(Value::Temporal(TemporalValue::Time {
                    nanos_since_midnight: time_to_nanos(&t),
                    offset_seconds: 0,
                }));
            }
            "LOCALTIME" | "LOCALTIME.STATEMENT" | "LOCALTIME.TRANSACTION" => {
                let local = frozen_now.with_timezone(&chrono::Local).time();
                return Ok(Value::Temporal(TemporalValue::LocalTime {
                    nanos_since_midnight: time_to_nanos(&local),
                }));
            }
            "DATETIME" | "DATETIME.STATEMENT" | "DATETIME.TRANSACTION" => {
                return Ok(Value::Temporal(TemporalValue::DateTime {
                    nanos_since_epoch: frozen_now.timestamp_nanos_opt().unwrap_or(0),
                    offset_seconds: 0,
                    timezone_name: None,
                }));
            }
            "LOCALDATETIME" | "LOCALDATETIME.STATEMENT" | "LOCALDATETIME.TRANSACTION" => {
                let local = frozen_now.with_timezone(&chrono::Local).naive_local();
                let epoch = NaiveDateTime::new(
                    NaiveDate::from_ymd_opt(1970, 1, 1).unwrap(),
                    NaiveTime::from_hms_opt(0, 0, 0).unwrap(),
                );
                let nanos = local
                    .signed_duration_since(epoch)
                    .num_nanoseconds()
                    .unwrap_or(0);
                return Ok(Value::Temporal(TemporalValue::LocalDateTime {
                    nanos_since_epoch: nanos,
                }));
            }
            _ => {}
        }
    }
    // Fall through to the regular eval for non-clock functions or functions with args
    eval_datetime_function(name, args)
}

pub fn eval_datetime_function(name: &str, args: &[Value]) -> Result<Value> {
    match name {
        // Basic constructors
        "DATE" => eval_date(args),
        "TIME" => eval_time(args),
        "DATETIME" => eval_datetime(args),
        "LOCALDATETIME" => eval_localdatetime(args),
        "LOCALTIME" => eval_localtime(args),
        "DURATION" => eval_duration(args),

        // Extraction functions
        "YEAR" => eval_extract(args, Component::Year),
        "MONTH" => eval_extract(args, Component::Month),
        "DAY" => eval_extract(args, Component::Day),
        "HOUR" => eval_extract(args, Component::Hour),
        "MINUTE" => eval_extract(args, Component::Minute),
        "SECOND" => eval_extract(args, Component::Second),

        // Epoch functions
        "DATETIME.FROMEPOCH" => eval_datetime_fromepoch(args),
        "DATETIME.FROMEPOCHMILLIS" => eval_datetime_fromepochmillis(args),

        // Truncate functions
        "DATE.TRUNCATE" => eval_truncate("date", args),
        "TIME.TRUNCATE" => eval_truncate("time", args),
        "DATETIME.TRUNCATE" => eval_truncate("datetime", args),
        "LOCALDATETIME.TRUNCATE" => eval_truncate("localdatetime", args),
        "LOCALTIME.TRUNCATE" => eval_truncate("localtime", args),

        // Transaction/statement/realtime functions (return current time)
        "DATETIME.TRANSACTION" | "DATETIME.STATEMENT" | "DATETIME.REALTIME" => eval_datetime(args),
        "DATE.TRANSACTION" | "DATE.STATEMENT" | "DATE.REALTIME" => eval_date(args),
        "TIME.TRANSACTION" | "TIME.STATEMENT" | "TIME.REALTIME" => eval_time(args),
        "LOCALTIME.TRANSACTION" | "LOCALTIME.STATEMENT" | "LOCALTIME.REALTIME" => {
            eval_localtime(args)
        }
        "LOCALDATETIME.TRANSACTION" | "LOCALDATETIME.STATEMENT" | "LOCALDATETIME.REALTIME" => {
            eval_localdatetime(args)
        }

        // Duration between functions
        "DURATION.BETWEEN" => eval_duration_between(args),
        "DURATION.INMONTHS" => eval_duration_in_months(args),
        "DURATION.INDAYS" => eval_duration_in_days(args),
        "DURATION.INSECONDS" => eval_duration_in_seconds(args),

        // BTIC temporal interval constructor
        "BTIC" => eval_btic(args),

        _ => Err(anyhow!("Unknown datetime function: {}", name)),
    }
}

/// Construct a BTIC temporal interval from a string literal.
///
/// Accepts ISO 8601 inspired formats via `uni_btic::parse::parse_btic_literal`:
/// - `btic('1985')` → year interval
/// - `btic('1985-03/2024-06')` → range with solidus
/// - `btic('~1985')` → approximate certainty
/// - `btic('2020-03/')` → ongoing (unbounded hi)
/// - `btic('/')` → fully unbounded
fn eval_btic(args: &[Value]) -> Result<Value> {
    if args.is_empty() {
        return Err(anyhow!("btic() requires exactly 1 argument"));
    }
    if args.len() > 1 {
        return Err(anyhow!("btic() accepts 1 argument, got {}", args.len()));
    }
    match &args[0] {
        Value::Null => Ok(Value::Null),
        Value::String(s) => {
            let btic = uni_btic::parse::parse_btic_literal(s).map_err(|e| {
                anyhow!(
                    "TypeError: InvalidArgumentValue - btic() failed to parse '{}': {}",
                    s,
                    e
                )
            })?;
            Ok(Value::Temporal(uni_common::TemporalValue::Btic {
                lo: btic.lo(),
                hi: btic.hi(),
                meta: btic.meta(),
            }))
        }
        other => Err(anyhow!("btic() argument must be a string, got: {}", other)),
    }
}

/// Check if value is a datetime string or temporal datetime.
pub fn is_datetime_value(val: &Value) -> bool {
    match val {
        Value::Temporal(TemporalValue::DateTime { .. }) => true,
        Value::String(s) => parse_datetime_utc(s).is_ok(),
        _ => false,
    }
}

/// Check if value is a date string or temporal date.
pub fn is_date_value(val: &Value) -> bool {
    match val {
        Value::Temporal(TemporalValue::Date { .. }) => true,
        Value::String(s) => NaiveDate::parse_from_str(s, "%Y-%m-%d").is_ok(),
        _ => false,
    }
}

/// Check if value is a duration (ISO 8601 string starting with 'P' or temporal duration).
///
/// Note: Numbers are NOT automatically treated as durations. The duration()
/// function can accept numbers as microseconds, but arbitrary numbers in
/// arithmetic expressions should not be interpreted as durations.
pub fn is_duration_value(val: &Value) -> bool {
    match val {
        Value::Temporal(TemporalValue::Duration { .. }) => true,
        Value::String(s) => is_duration_string(s),
        _ => false,
    }
}

/// Check if a value is a duration string OR an integer (microseconds).
///
/// This is used for temporal arithmetic where integers are implicitly treated
/// as durations when paired with datetime/date values. For standalone type
/// checking, use `is_duration_value` instead.
pub fn is_duration_or_micros(val: &Value) -> bool {
    is_duration_value(val) || matches!(val, Value::Int(_))
}

/// Convert a duration value (ISO 8601 string or i64 micros) to microseconds.
pub fn duration_to_micros(val: &Value) -> Result<i64> {
    match val {
        Value::String(s) => {
            let duration = parse_duration_to_cypher(s)?;
            Ok(duration.to_micros())
        }
        Value::Int(i) => Ok(*i),
        _ => Err(anyhow!("Expected duration value")),
    }
}

/// Add duration (microseconds) to datetime.
pub fn add_duration_to_datetime(dt_str: &str, micros: i64) -> Result<String> {
    let dt = parse_datetime_utc(dt_str)?;
    let result = dt + Duration::microseconds(micros);
    Ok(result.to_rfc3339())
}

/// Add duration (microseconds) to date.
pub fn add_duration_to_date(date_str: &str, micros: i64) -> Result<String> {
    let date = NaiveDate::parse_from_str(date_str, "%Y-%m-%d")?;
    let dt = date
        .and_hms_opt(0, 0, 0)
        .ok_or_else(|| anyhow!("Invalid date"))?;
    let result = dt + Duration::microseconds(micros);
    Ok(result.format("%Y-%m-%d").to_string())
}

/// Subtract two datetimes, return duration in microseconds.
pub fn datetime_difference(dt1_str: &str, dt2_str: &str) -> Result<i64> {
    let dt1 = parse_datetime_utc(dt1_str)?;
    let dt2 = parse_datetime_utc(dt2_str)?;
    dt1.signed_duration_since(dt2)
        .num_microseconds()
        .ok_or_else(|| anyhow!("Duration overflow"))
}

/// Parse a duration string to microseconds.
///
/// Supports ISO 8601 format (P1DT1H30M) and simple formats (1h30m, 90s, etc.)
pub fn parse_duration_to_micros(s: &str) -> Result<i64> {
    let s = s.trim();

    // ISO 8601 format: P[n]Y[n]M[n]DT[n]H[n]M[n]S
    if s.starts_with(['P', 'p']) {
        return parse_iso8601_duration(s);
    }

    // Simple format: combinations of NdNhNmNs (e.g., "1d2h30m", "90s", "1h30m")
    parse_simple_duration(s)
}

/// Parse a duration string to a CypherDuration with preserved components.
pub fn parse_duration_to_cypher(s: &str) -> Result<CypherDuration> {
    let s = s.trim();

    // ISO 8601 format: P[n]Y[n]M[n]DT[n]H[n]M[n]S
    if s.starts_with(['P', 'p']) {
        return parse_iso8601_duration_cypher(s);
    }

    // Simple format: fall back to microseconds conversion
    let micros = parse_simple_duration(s)?;
    Ok(CypherDuration::from_micros(micros))
}

/// Parse date-time style ISO 8601 duration format (e.g., `P2012-02-02T14:37:21.545`).
///
/// Format: `PYYYY-MM-DDTHH:MM:SS.fff`
fn parse_datetime_style_duration(s: &str) -> Result<CypherDuration> {
    let body = &s[1..]; // Skip 'P'

    // Split on 'T' for date and time parts
    let (date_part, time_part) = if let Some(t_pos) = body.find('T') {
        (&body[..t_pos], Some(&body[t_pos + 1..]))
    } else {
        (body, None)
    };

    // Parse date part: YYYY-MM-DD
    let date_parts: Vec<&str> = date_part.split('-').collect();
    if date_parts.len() != 3 {
        return Err(anyhow!(
            "Invalid date-time style duration date: {}",
            date_part
        ));
    }
    let years: i64 = date_parts[0]
        .parse()
        .map_err(|_| anyhow!("Invalid years"))?;
    let month_val: i64 = date_parts[1]
        .parse()
        .map_err(|_| anyhow!("Invalid months"))?;
    let day_val: i64 = date_parts[2].parse().map_err(|_| anyhow!("Invalid days"))?;

    let months = years * 12 + month_val;
    let days = day_val;

    // Parse time part: HH:MM:SS.fff
    let nanos = if let Some(tp) = time_part {
        let time_parts: Vec<&str> = tp.split(':').collect();
        if time_parts.len() != 3 {
            return Err(anyhow!("Invalid date-time style duration time: {}", tp));
        }
        let hours: f64 = time_parts[0]
            .parse()
            .map_err(|_| anyhow!("Invalid hours"))?;
        let minutes: f64 = time_parts[1]
            .parse()
            .map_err(|_| anyhow!("Invalid minutes"))?;
        let seconds: f64 = time_parts[2]
            .parse()
            .map_err(|_| anyhow!("Invalid seconds"))?;
        (hours * 3600.0 * NANOS_PER_SECOND as f64
            + minutes * 60.0 * NANOS_PER_SECOND as f64
            + seconds * NANOS_PER_SECOND as f64) as i64
    } else {
        0
    };

    Ok(CypherDuration::new(months, days, nanos))
}

/// Parse ISO 8601 duration format to CypherDuration (preserves month/day/time components).
fn parse_iso8601_duration_cypher(s: &str) -> Result<CypherDuration> {
    // Detect date-time style duration: after 'P', if char at position 4 is '-' and length >= 10
    // e.g., P2012-02-02T14:37:21.545
    if s.len() >= 11
        && s.as_bytes().get(5) == Some(&b'-')
        && s.as_bytes().get(1).is_some_and(|b| b.is_ascii_digit())
    {
        return parse_datetime_style_duration(s);
    }

    let s = &s[1..]; // Skip 'P'
    let mut months: i64 = 0;
    let mut days: i64 = 0;
    let mut nanos: i64 = 0;
    let mut in_time_part = false;
    let mut num_buf = String::new();

    for c in s.chars() {
        if c == 'T' || c == 't' {
            in_time_part = true;
            continue;
        }

        if c.is_ascii_digit() || c == '.' || c == '-' {
            num_buf.push(c);
        } else {
            if num_buf.is_empty() {
                continue;
            }
            let num: f64 = num_buf
                .parse()
                .map_err(|_| anyhow!("Invalid duration number"))?;
            num_buf.clear();

            match c {
                'Y' | 'y' => {
                    // Cascade: whole years → months, fractional years → via average Gregorian year
                    let whole = num.trunc() as i64;
                    let frac = num.fract();
                    months += whole * 12;
                    if frac != 0.0 {
                        // Fractional year → fractional months → cascade
                        let frac_months = frac * 12.0;
                        let whole_frac_months = frac_months.trunc() as i64;
                        let frac_frac_months = frac_months.fract();
                        months += whole_frac_months;
                        // Cascade remaining fractional months via average Gregorian month (2,629,746 seconds)
                        let frac_secs = frac_frac_months * 2_629_746.0;
                        let extra_days = (frac_secs / SECONDS_PER_DAY as f64).trunc() as i64;
                        let remaining_secs =
                            frac_secs - (extra_days as f64 * SECONDS_PER_DAY as f64);
                        days += extra_days;
                        nanos += (remaining_secs * NANOS_PER_SECOND as f64) as i64;
                    }
                }
                'M' if !in_time_part => {
                    // Cascade: whole months, fractional months → days + nanos via average Gregorian month
                    let whole = num.trunc() as i64;
                    let frac = num.fract();
                    months += whole;
                    if frac != 0.0 {
                        let frac_secs = frac * 2_629_746.0;
                        let extra_days = (frac_secs / SECONDS_PER_DAY as f64).trunc() as i64;
                        let remaining_secs =
                            frac_secs - (extra_days as f64 * SECONDS_PER_DAY as f64);
                        days += extra_days;
                        nanos += (remaining_secs * NANOS_PER_SECOND as f64) as i64;
                    }
                }
                'W' | 'w' => {
                    // Cascade: weeks to days, fractional days to nanos
                    let total_days_f = num * 7.0;
                    let whole = total_days_f.trunc() as i64;
                    let frac = total_days_f.fract();
                    days += whole;
                    nanos += (frac * NANOS_PER_DAY as f64) as i64;
                }
                'D' | 'd' => {
                    // Cascade: whole days, fractional days to nanos
                    let whole = num.trunc() as i64;
                    let frac = num.fract();
                    days += whole;
                    nanos += (frac * NANOS_PER_DAY as f64) as i64;
                }
                'H' | 'h' => nanos += (num * 3600.0 * NANOS_PER_SECOND as f64) as i64,
                'M' | 'm' if in_time_part => nanos += (num * 60.0 * NANOS_PER_SECOND as f64) as i64,
                'S' | 's' => nanos += (num * NANOS_PER_SECOND as f64) as i64,
                _ => return Err(anyhow!("Invalid ISO 8601 duration designator: {}", c)),
            }
        }
    }

    Ok(CypherDuration::new(months, days, nanos))
}

// ============================================================================
// Component Extraction
// ============================================================================

enum Component {
    Year,
    Month,
    Day,
    Hour,
    Minute,
    Second,
}

fn eval_extract(args: &[Value], component: Component) -> Result<Value> {
    if args.len() != 1 {
        return Err(anyhow!("Extract function requires 1 argument"));
    }
    match &args[0] {
        Value::Temporal(tv) => {
            let result = match component {
                Component::Year => tv.year(),
                Component::Month => tv.month(),
                Component::Day => tv.day(),
                Component::Hour => tv.hour(),
                Component::Minute => tv.minute(),
                Component::Second => tv.second(),
            };
            match result {
                Some(v) => Ok(Value::Int(v)),
                None => Err(anyhow!("Temporal value does not have requested component")),
            }
        }
        Value::String(s) => {
            // Try parsing as DateTime, then NaiveDateTime, then NaiveDate, then NaiveTime
            if let Ok(dt) = DateTime::parse_from_rfc3339(s) {
                return Ok(Value::Int(extract_component(&dt, &component) as i64));
            }
            if let Ok(dt) = NaiveDateTime::parse_from_str(s, "%Y-%m-%d %H:%M:%S") {
                return Ok(Value::Int(extract_component(&dt, &component) as i64));
            }

            match component {
                Component::Year | Component::Month | Component::Day => {
                    if let Ok(d) = NaiveDate::parse_from_str(s, "%Y-%m-%d") {
                        return Ok(Value::Int(match component {
                            Component::Year => d.year() as i64,
                            Component::Month => d.month() as i64,
                            Component::Day => d.day() as i64,
                            _ => unreachable!(),
                        }));
                    }
                }
                Component::Hour | Component::Minute | Component::Second => {
                    if let Ok(t) = NaiveTime::parse_from_str(s, "%H:%M:%S") {
                        return Ok(Value::Int(match component {
                            Component::Hour => t.hour() as i64,
                            Component::Minute => t.minute() as i64,
                            Component::Second => t.second() as i64,
                            _ => unreachable!(),
                        }));
                    }
                }
            }

            Err(anyhow!("Could not parse date/time string for extraction"))
        }
        Value::Null => Ok(Value::Null),
        _ => Err(anyhow!(
            "Extract function expects a temporal or string argument"
        )),
    }
}

fn extract_component<T: Datelike + Timelike>(dt: &T, component: &Component) -> i32 {
    match component {
        Component::Year => dt.year(),
        Component::Month => dt.month() as i32,
        Component::Day => dt.day() as i32,
        Component::Hour => dt.hour() as i32,
        Component::Minute => dt.minute() as i32,
        Component::Second => dt.second() as i32,
    }
}

// ============================================================================
// Temporal Component Accessors (for property access on temporals)
// ============================================================================

/// Evaluate a temporal component accessor.
///
/// This handles property access on temporal values like `dt.quarter`, `dt.week`,
/// `dt.dayOfWeek`, `dt.timezone`, etc.
pub fn eval_temporal_accessor(temporal_str: &str, component: &str) -> Result<Value> {
    let component_lower = component.to_lowercase();
    match component_lower.as_str() {
        // Basic date components (already handled by eval_extract but also here for consistency)
        "year" => extract_year(temporal_str),
        "month" => extract_month(temporal_str),
        "day" => extract_day(temporal_str),
        "hour" => extract_hour(temporal_str),
        "minute" => extract_minute(temporal_str),
        "second" => extract_second(temporal_str),

        // Extended date components
        "quarter" => extract_quarter(temporal_str),
        "week" => extract_week(temporal_str),
        "weekyear" => extract_week_year(temporal_str),
        "ordinalday" => extract_ordinal_day(temporal_str),
        "dayofweek" | "weekday" => extract_day_of_week(temporal_str),
        "dayofquarter" => extract_day_of_quarter(temporal_str),

        // Sub-second components
        "millisecond" => extract_millisecond(temporal_str),
        "microsecond" => extract_microsecond(temporal_str),
        "nanosecond" => extract_nanosecond(temporal_str),

        // Timezone components
        "timezone" => extract_timezone_name_from_str(temporal_str),
        "offset" => extract_offset_string(temporal_str),
        "offsetminutes" => extract_offset_minutes(temporal_str),
        "offsetseconds" => extract_offset_seconds(temporal_str),

        // Epoch components
        "epochseconds" => extract_epoch_seconds(temporal_str),
        "epochmillis" => extract_epoch_millis(temporal_str),

        _ => Err(anyhow!("Unknown temporal component: {}", component)),
    }
}

/// Evaluate a temporal component accessor on a `Value`.
///
/// Handles `Value::Temporal` (converts to string representation then delegates),
/// `Value::String` (direct string-based extraction), and `Value::Null`.
pub fn eval_temporal_accessor_value(val: &Value, component: &str) -> Result<Value> {
    match val {
        Value::Null => Ok(Value::Null),
        // Non-graph map property access can be translated through _temporal_property
        // for accessor-like names such as `year`. For map values, preserve normal
        // Cypher map semantics: treat it as key lookup.
        Value::Map(map) => Ok(map.get(component).cloned().unwrap_or(Value::Null)),
        Value::Temporal(tv) => {
            // For offset-related accessors on temporal values, extract directly
            // from the TemporalValue fields to avoid lossy string round-trip.
            let comp_lower = component.to_lowercase();
            match comp_lower.as_str() {
                "timezone" => {
                    return match tv {
                        TemporalValue::DateTime {
                            timezone_name,
                            offset_seconds,
                            ..
                        } => Ok(match timezone_name {
                            Some(name) => Value::String(name.clone()),
                            None => Value::String(format_timezone_offset(*offset_seconds)),
                        }),
                        TemporalValue::Time { offset_seconds, .. } => {
                            Ok(Value::String(format_timezone_offset(*offset_seconds)))
                        }
                        _ => Ok(Value::Null),
                    };
                }
                "offset" => {
                    return match tv {
                        TemporalValue::DateTime { offset_seconds, .. }
                        | TemporalValue::Time { offset_seconds, .. } => {
                            Ok(Value::String(format_timezone_offset(*offset_seconds)))
                        }
                        _ => Ok(Value::Null),
                    };
                }
                "offsetminutes" => {
                    return match tv {
                        TemporalValue::DateTime { offset_seconds, .. }
                        | TemporalValue::Time { offset_seconds, .. } => {
                            Ok(Value::Int((*offset_seconds / 60) as i64))
                        }
                        _ => Ok(Value::Null),
                    };
                }
                "offsetseconds" => {
                    return match tv {
                        TemporalValue::DateTime { offset_seconds, .. }
                        | TemporalValue::Time { offset_seconds, .. } => {
                            Ok(Value::Int(*offset_seconds as i64))
                        }
                        _ => Ok(Value::Null),
                    };
                }
                "epochseconds" => {
                    return match tv {
                        TemporalValue::DateTime {
                            nanos_since_epoch, ..
                        } => Ok(Value::Int(nanos_since_epoch / 1_000_000_000)),
                        TemporalValue::LocalDateTime { nanos_since_epoch } => {
                            Ok(Value::Int(nanos_since_epoch / 1_000_000_000))
                        }
                        TemporalValue::Date { days_since_epoch } => {
                            Ok(Value::Int(*days_since_epoch as i64 * 86400))
                        }
                        _ => Ok(Value::Null),
                    };
                }
                "epochmillis" => {
                    return match tv {
                        TemporalValue::DateTime {
                            nanos_since_epoch, ..
                        } => Ok(Value::Int(nanos_since_epoch / 1_000_000)),
                        TemporalValue::LocalDateTime { nanos_since_epoch } => {
                            Ok(Value::Int(nanos_since_epoch / 1_000_000))
                        }
                        TemporalValue::Date { days_since_epoch } => {
                            Ok(Value::Int(*days_since_epoch as i64 * 86400 * 1000))
                        }
                        _ => Ok(Value::Null),
                    };
                }
                _ => {}
            }
            // For all other accessors, convert to string and delegate
            let temporal_str = tv.to_string();
            eval_temporal_accessor(&temporal_str, component)
        }
        Value::String(s) => eval_temporal_accessor(s, component),
        _ => Err(anyhow!(
            "Cannot access temporal property '{}' on non-temporal value",
            component
        )),
    }
}

/// Check if a property name is a valid temporal accessor.
pub fn is_temporal_accessor(property: &str) -> bool {
    let property_lower = property.to_lowercase();
    matches!(
        property_lower.as_str(),
        "year"
            | "month"
            | "day"
            | "hour"
            | "minute"
            | "second"
            | "quarter"
            | "week"
            | "weekyear"
            | "ordinalday"
            | "dayofweek"
            | "weekday"
            | "dayofquarter"
            | "millisecond"
            | "microsecond"
            | "nanosecond"
            | "timezone"
            | "offset"
            | "offsetminutes"
            | "offsetseconds"
            | "epochseconds"
            | "epochmillis"
    )
}

/// Check if a string looks like a temporal value (date, time, datetime).
pub fn is_temporal_string(s: &str) -> bool {
    let bytes = s.as_bytes();
    if bytes.len() < 8 {
        return false;
    }

    // Date pattern: YYYY-MM-DD
    (bytes.len() >= 10 && bytes[4] == b'-' && bytes[7] == b'-')
    // Time pattern: HH:MM:SS
    || (bytes[2] == b':' && bytes[5] == b':')
    // Duration pattern: starts with P
    || (bytes[0] == b'P' || bytes[0] == b'p')
}

/// Check if a string looks like a duration value.
pub fn is_duration_string(s: &str) -> bool {
    s.starts_with(['P', 'p'])
}

// Individual component extractors

fn extract_date_component(s: &str, f: impl FnOnce(NaiveDate) -> i64) -> Result<Value> {
    let (date, _, _) = parse_datetime_with_tz(s)?;
    Ok(Value::Int(f(date)))
}

fn extract_time_component(s: &str, f: impl FnOnce(NaiveTime) -> i64) -> Result<Value> {
    let (_, time, _) = parse_datetime_with_tz(s)?;
    Ok(Value::Int(f(time)))
}

fn extract_year(s: &str) -> Result<Value> {
    extract_date_component(s, |d| d.year() as i64)
}

fn extract_month(s: &str) -> Result<Value> {
    extract_date_component(s, |d| d.month() as i64)
}

fn extract_day(s: &str) -> Result<Value> {
    extract_date_component(s, |d| d.day() as i64)
}

fn extract_hour(s: &str) -> Result<Value> {
    extract_time_component(s, |t| t.hour() as i64)
}

fn extract_minute(s: &str) -> Result<Value> {
    extract_time_component(s, |t| t.minute() as i64)
}

fn extract_second(s: &str) -> Result<Value> {
    extract_time_component(s, |t| t.second() as i64)
}

fn extract_quarter(s: &str) -> Result<Value> {
    extract_date_component(s, |d| ((d.month() - 1) / 3 + 1) as i64)
}

fn extract_week(s: &str) -> Result<Value> {
    extract_date_component(s, |d| d.iso_week().week() as i64)
}

fn extract_week_year(s: &str) -> Result<Value> {
    extract_date_component(s, |d| d.iso_week().year() as i64)
}

fn extract_ordinal_day(s: &str) -> Result<Value> {
    extract_date_component(s, |d| d.ordinal() as i64)
}

fn extract_day_of_week(s: &str) -> Result<Value> {
    // ISO weekday: Monday = 1, Sunday = 7
    extract_date_component(s, |d| (d.weekday().num_days_from_monday() + 1) as i64)
}

fn extract_day_of_quarter(s: &str) -> Result<Value> {
    let (date, _, _) = parse_datetime_with_tz(s)?;
    let quarter = (date.month() - 1) / 3;
    let first_month_of_quarter = quarter * 3 + 1;
    let quarter_start = NaiveDate::from_ymd_opt(date.year(), first_month_of_quarter, 1)
        .ok_or_else(|| {
            anyhow!(
                "Invalid quarter start for year={}, month={}",
                date.year(),
                first_month_of_quarter
            )
        })?;
    let day_of_quarter = (date - quarter_start).num_days() + 1;
    Ok(Value::Int(day_of_quarter))
}

fn extract_millisecond(s: &str) -> Result<Value> {
    extract_time_component(s, |t| (t.nanosecond() / 1_000_000) as i64)
}

fn extract_microsecond(s: &str) -> Result<Value> {
    extract_time_component(s, |t| (t.nanosecond() / 1_000) as i64)
}

fn extract_nanosecond(s: &str) -> Result<Value> {
    extract_time_component(s, |t| t.nanosecond() as i64)
}

fn extract_timezone_name_from_str(s: &str) -> Result<Value> {
    let (_, _, tz_info) = parse_datetime_with_tz(s)?;
    match tz_info {
        Some(TimezoneInfo::Named(tz)) => Ok(Value::String(tz.name().to_string())),
        Some(TimezoneInfo::FixedOffset(offset)) => {
            // Format as offset string with optional seconds
            let secs = offset.local_minus_utc();
            Ok(Value::String(format_timezone_offset(secs)))
        }
        None => Ok(Value::Null),
    }
}

fn extract_offset_string(s: &str) -> Result<Value> {
    let (date, time, tz_info) = parse_datetime_with_tz(s)?;
    match tz_info {
        Some(ref tz) => {
            let ndt = NaiveDateTime::new(date, time);
            let offset = tz.offset_for_local(&ndt)?;
            Ok(Value::String(format_timezone_offset(
                offset.local_minus_utc(),
            )))
        }
        None => Ok(Value::Null),
    }
}

fn extract_offset_total_seconds(s: &str) -> Result<i32> {
    let (date, time, tz_info) = parse_datetime_with_tz(s)?;
    match tz_info {
        Some(ref tz) => {
            let ndt = NaiveDateTime::new(date, time);
            let offset = tz.offset_for_local(&ndt)?;
            Ok(offset.local_minus_utc())
        }
        None => Ok(0),
    }
}

fn extract_offset_minutes(s: &str) -> Result<Value> {
    Ok(Value::Int((extract_offset_total_seconds(s)? / 60) as i64))
}

fn extract_offset_seconds(s: &str) -> Result<Value> {
    Ok(Value::Int(extract_offset_total_seconds(s)? as i64))
}

fn parse_as_utc(s: &str) -> Result<DateTime<Utc>> {
    let (date, time, tz_info) = parse_datetime_with_tz(s)?;
    let local_ndt = NaiveDateTime::new(date, time);

    if let Some(tz) = tz_info {
        let offset = tz.offset_for_local(&local_ndt)?;
        let utc_ndt = local_ndt - Duration::seconds(offset.local_minus_utc() as i64);
        Ok(DateTime::<Utc>::from_naive_utc_and_offset(utc_ndt, Utc))
    } else {
        Ok(DateTime::<Utc>::from_naive_utc_and_offset(local_ndt, Utc))
    }
}

fn extract_epoch_seconds(s: &str) -> Result<Value> {
    Ok(Value::Int(parse_as_utc(s)?.timestamp()))
}

fn extract_epoch_millis(s: &str) -> Result<Value> {
    Ok(Value::Int(parse_as_utc(s)?.timestamp_millis()))
}

// ============================================================================
// Duration Component Accessors
// ============================================================================

/// Evaluate a duration component accessor using Euclidean division.
///
/// Uses `div_euclid()` / `rem_euclid()` so remainders are always non-negative,
/// matching the TCK expectations for negative durations.
pub fn eval_duration_accessor(duration_str: &str, component: &str) -> Result<Value> {
    let duration = parse_duration_to_cypher(duration_str)?;
    let component_lower = component.to_lowercase();

    let total_months = duration.months;
    let total_nanos = duration.nanos;
    let total_secs = total_nanos.div_euclid(NANOS_PER_SECOND);

    match component_lower.as_str() {
        // Total components (converted to that unit)
        "years" => Ok(Value::Int(total_months.div_euclid(12))),
        "quarters" => Ok(Value::Int(total_months.div_euclid(3))),
        "months" => Ok(Value::Int(total_months)),
        "weeks" => Ok(Value::Int(duration.days.div_euclid(7))),
        "days" => Ok(Value::Int(duration.days)),
        "hours" => Ok(Value::Int(total_secs.div_euclid(3600))),
        "minutes" => Ok(Value::Int(total_secs.div_euclid(60))),
        "seconds" => Ok(Value::Int(total_secs)),
        "milliseconds" => Ok(Value::Int(total_nanos.div_euclid(1_000_000))),
        "microseconds" => Ok(Value::Int(total_nanos.div_euclid(1_000))),
        "nanoseconds" => Ok(Value::Int(total_nanos)),

        // "Of" accessors (remainder within larger unit) using Euclidean remainder
        "quartersofyear" => Ok(Value::Int(total_months.rem_euclid(12) / 3)),
        "monthsofquarter" => Ok(Value::Int(total_months.rem_euclid(3))),
        "monthsofyear" => Ok(Value::Int(total_months.rem_euclid(12))),
        "daysofweek" => Ok(Value::Int(duration.days.rem_euclid(7))),
        "hoursofday" => Ok(Value::Int(total_secs.div_euclid(3600).rem_euclid(24))),
        "minutesofhour" => Ok(Value::Int(total_secs.div_euclid(60).rem_euclid(60))),
        "secondsofminute" => Ok(Value::Int(total_secs.rem_euclid(60))),
        "millisecondsofsecond" => Ok(Value::Int(
            total_nanos.div_euclid(1_000_000).rem_euclid(1000),
        )),
        "microsecondsofsecond" => Ok(Value::Int(
            total_nanos.div_euclid(1_000).rem_euclid(1_000_000),
        )),
        "nanosecondsofsecond" => Ok(Value::Int(total_nanos.rem_euclid(NANOS_PER_SECOND))),

        _ => Err(anyhow!("Unknown duration component: {}", component)),
    }
}

/// Check if a property name is a valid duration accessor.
pub fn is_duration_accessor(property: &str) -> bool {
    let property_lower = property.to_lowercase();
    matches!(
        property_lower.as_str(),
        "years"
            | "quarters"
            | "months"
            | "weeks"
            | "days"
            | "hours"
            | "minutes"
            | "seconds"
            | "milliseconds"
            | "microseconds"
            | "nanoseconds"
            | "quartersofyear"
            | "monthsofquarter"
            | "monthsofyear"
            | "daysofweek"
            | "hoursofday"
            | "minutesofhour"
            | "secondsofminute"
            | "millisecondsofsecond"
            | "microsecondsofsecond"
            | "nanosecondsofsecond"
    )
}

// ============================================================================
// Date Constructor
// ============================================================================

fn eval_date(args: &[Value]) -> Result<Value> {
    if args.is_empty() {
        // Current date
        let now = Utc::now().date_naive();
        return Ok(Value::Temporal(TemporalValue::Date {
            days_since_epoch: date_to_days_since_epoch(&now),
        }));
    }

    match &args[0] {
        Value::String(s) => {
            match parse_date_string(s) {
                Ok(date) => Ok(Value::Temporal(TemporalValue::Date {
                    days_since_epoch: date_to_days_since_epoch(&date),
                })),
                Err(e) => {
                    if parse_extended_date_string(s).is_some() {
                        // Out-of-range years cannot fit the current TemporalValue Date encoding.
                        Ok(Value::String(s.clone()))
                    } else {
                        Err(e)
                    }
                }
            }
        }
        Value::Temporal(TemporalValue::Date { .. }) => Ok(args[0].clone()),
        // Cross-type: extract date component from any temporal with a date
        Value::Temporal(tv) => {
            if let Some(date) = tv.to_date() {
                Ok(Value::Temporal(TemporalValue::Date {
                    days_since_epoch: date_to_days_since_epoch(&date),
                }))
            } else {
                Err(anyhow!("date(): temporal value has no date component"))
            }
        }
        Value::Map(map) => eval_date_from_map(map),
        Value::Null => Ok(Value::Null),
        _ => Err(anyhow!("date() expects a string or map argument")),
    }
}

/// Convert a NaiveDate to days since Unix epoch.
fn date_to_days_since_epoch(date: &NaiveDate) -> i32 {
    let epoch = NaiveDate::from_ymd_opt(1970, 1, 1).unwrap();
    (date.signed_duration_since(epoch)).num_days() as i32
}

fn eval_date_from_map(map: &HashMap<String, Value>) -> Result<Value> {
    // Check if we have a 'date' field to copy from another date/datetime
    if let Some(dt_val) = map.get("date") {
        return eval_date_from_projection(map, dt_val);
    }

    let date = build_date_from_map(map)?;
    Ok(Value::Temporal(TemporalValue::Date {
        days_since_epoch: date_to_days_since_epoch(&date),
    }))
}

/// Handle date construction from projection (copying from another temporal value).
fn eval_date_from_projection(map: &HashMap<String, Value>, source: &Value) -> Result<Value> {
    let source_date = temporal_or_string_to_date(source)?;
    let date = build_date_from_projection(map, &source_date)?;
    Ok(Value::Temporal(TemporalValue::Date {
        days_since_epoch: date_to_days_since_epoch(&date),
    }))
}

/// Extract a NaiveDate from a Value::Temporal or Value::String.
fn temporal_or_string_to_date(val: &Value) -> Result<NaiveDate> {
    match val {
        Value::Temporal(tv) => tv
            .to_date()
            .ok_or_else(|| anyhow!("Temporal value has no date component")),
        Value::String(s) => parse_datetime_with_tz(s).map(|(date, _, _)| date),
        _ => Err(anyhow!(
            "Expected temporal or string value for date extraction"
        )),
    }
}

/// Build a NaiveDate from projection map, using source_date for defaults.
///
/// Supports multiple override modes:
/// - Week-based: override week, dayOfWeek (uses weekYear from source)
/// - Ordinal: override ordinalDay (uses year from source)
/// - Quarter: override quarter, dayOfQuarter (uses year from source)
/// - Calendar: override year, month, day (defaults from source)
fn build_date_from_projection(
    map: &HashMap<String, Value>,
    source_date: &NaiveDate,
) -> Result<NaiveDate> {
    // Week-based: {date: other, week: 2, dayOfWeek: 3}
    if map.contains_key("week") {
        let week_year = map
            .get("weekYear")
            .and_then(|v| v.as_i64())
            .map(|v| v as i32)
            .unwrap_or_else(|| source_date.iso_week().year());
        let week = map.get("week").and_then(|v| v.as_i64()).unwrap_or(1) as u32;
        let dow = map
            .get("dayOfWeek")
            .and_then(|v| v.as_i64())
            .unwrap_or_else(|| source_date.weekday().number_from_monday() as i64)
            as u32;
        return build_date_from_week(week_year, week, dow);
    }

    // Ordinal: {date: other, ordinalDay: 202}
    if map.contains_key("ordinalDay") {
        let year = map
            .get("year")
            .and_then(|v| v.as_i64())
            .map(|v| v as i32)
            .unwrap_or(source_date.year());
        let ordinal = map
            .get("ordinalDay")
            .and_then(|v| v.as_i64())
            .unwrap_or(source_date.ordinal() as i64) as u32;
        return NaiveDate::from_yo_opt(year, ordinal)
            .ok_or_else(|| anyhow!("Invalid ordinal day: {} for year {}", ordinal, year));
    }

    // Quarter: {date: other, quarter: 3, dayOfQuarter: 45}
    if map.contains_key("quarter") {
        let year = map
            .get("year")
            .and_then(|v| v.as_i64())
            .map(|v| v as i32)
            .unwrap_or(source_date.year());
        let quarter = map.get("quarter").and_then(|v| v.as_i64()).unwrap_or(1) as u32;
        let doq = map
            .get("dayOfQuarter")
            .and_then(|v| v.as_i64())
            .unwrap_or_else(|| day_of_quarter(source_date) as i64) as u32;
        return build_date_from_quarter(year, quarter, doq);
    }

    // Calendar-based: year, month, day with defaults from source
    let year = map
        .get("year")
        .and_then(|v| v.as_i64())
        .map(|v| v as i32)
        .unwrap_or(source_date.year());
    let month = map
        .get("month")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_date.month());
    let day = map
        .get("day")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_date.day());

    NaiveDate::from_ymd_opt(year, month, day).ok_or_else(|| anyhow!("Invalid date in projection"))
}

/// Build a NaiveDate from map fields.
///
/// Supports multiple construction modes:
/// - Calendar: year, month, day
/// - Week-based: year, week, dayOfWeek
/// - Ordinal: year, ordinalDay
/// - Quarter: year, quarter, dayOfQuarter
fn build_date_from_map(map: &HashMap<String, Value>) -> Result<NaiveDate> {
    // Extract year (required for all date map constructors)
    let year = map
        .get("year")
        .and_then(|v| v.as_i64())
        .ok_or_else(|| anyhow!("date/datetime map requires 'year' field"))? as i32;

    // Week-based: {year: 1984, week: 10, dayOfWeek: 3}
    if let Some(week) = map.get("week").and_then(|v| v.as_i64()) {
        let dow = map.get("dayOfWeek").and_then(|v| v.as_i64()).unwrap_or(1);
        return build_date_from_week(year, week as u32, dow as u32);
    }

    // Ordinal: {year: 1984, ordinalDay: 202}
    if let Some(ordinal) = map.get("ordinalDay").and_then(|v| v.as_i64()) {
        return NaiveDate::from_yo_opt(year, ordinal as u32)
            .ok_or_else(|| anyhow!("Invalid ordinal day: {} for year {}", ordinal, year));
    }

    // Quarter: {year: 1984, quarter: 3, dayOfQuarter: 45}
    if let Some(quarter) = map.get("quarter").and_then(|v| v.as_i64()) {
        let doq = map
            .get("dayOfQuarter")
            .and_then(|v| v.as_i64())
            .unwrap_or(1);
        return build_date_from_quarter(year, quarter as u32, doq as u32);
    }

    // Calendar: standard year/month/day (with defaults)
    let month = map.get("month").and_then(|v| v.as_i64()).unwrap_or(1) as u32;
    let day = map.get("day").and_then(|v| v.as_i64()).unwrap_or(1) as u32;

    NaiveDate::from_ymd_opt(year, month, day)
        .ok_or_else(|| anyhow!("Invalid date: year={}, month={}, day={}", year, month, day))
}

/// Build date from ISO week number (returns NaiveDate).
fn build_date_from_week(year: i32, week: u32, day_of_week: u32) -> Result<NaiveDate> {
    if !(1..=53).contains(&week) {
        return Err(anyhow!("Week must be between 1 and 53"));
    }
    if !(1..=7).contains(&day_of_week) {
        return Err(anyhow!("Day of week must be between 1 and 7"));
    }

    // Find January 4th of the given year (always in week 1)
    let jan4 =
        NaiveDate::from_ymd_opt(year, 1, 4).ok_or_else(|| anyhow!("Invalid year: {}", year))?;

    // Find Monday of week 1
    let iso_week_day = jan4.weekday().num_days_from_monday();
    let week1_monday = jan4 - Duration::days(iso_week_day as i64);

    // Calculate target date
    let days_offset = ((week - 1) * 7 + (day_of_week - 1)) as i64;
    Ok(week1_monday + Duration::days(days_offset))
}

/// Compute the 1-based day-of-quarter for a given date.
fn day_of_quarter(date: &NaiveDate) -> u32 {
    let quarter_start_month = ((date.month() - 1) / 3) * 3 + 1;
    let quarter_start = NaiveDate::from_ymd_opt(date.year(), quarter_start_month, 1).unwrap();
    (date.signed_duration_since(quarter_start).num_days() + 1) as u32
}

/// Build date from quarter and day of quarter (returns NaiveDate).
fn build_date_from_quarter(year: i32, quarter: u32, day_of_quarter: u32) -> Result<NaiveDate> {
    if !(1..=4).contains(&quarter) {
        return Err(anyhow!("Quarter must be between 1 and 4"));
    }

    // First day of quarter
    let first_month = (quarter - 1) * 3 + 1;
    let quarter_start = NaiveDate::from_ymd_opt(year, first_month, 1)
        .ok_or_else(|| anyhow!("Invalid quarter start"))?;

    // Add days (day_of_quarter is 1-based)
    let result = quarter_start + Duration::days((day_of_quarter - 1) as i64);

    // Validate the result is still in the same quarter
    let result_quarter = (result.month() - 1) / 3 + 1;
    if result_quarter != quarter || result.year() != year {
        return Err(anyhow!(
            "Day {} is out of range for quarter {}",
            day_of_quarter,
            quarter
        ));
    }

    Ok(result)
}

fn parse_date_string(s: &str) -> Result<NaiveDate> {
    NaiveDate::parse_from_str(s, "%Y-%m-%d")
        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%d %H:%M:%S").map(|dt| dt.date()))
        .or_else(|_| {
            // Try parsing RFC3339 datetime and extract date
            DateTime::parse_from_rfc3339(s).map(|dt| dt.date_naive())
        })
        // T-separated datetime formats (e.g., from localdatetime constructor)
        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%dT%H:%M:%S%.f").map(|dt| dt.date()))
        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%dT%H:%M:%S").map(|dt| dt.date()))
        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%dT%H:%M").map(|dt| dt.date()))
        // Compact ISO 8601 date formats (YYYYMMDD, YYYYDDD, YYYYWww, YYYYWwwD)
        .or_else(|e| try_parse_compact_date(s).ok_or(e))
        .or_else(|_| {
            // Fallback: use full datetime parser (handles offsets like +01:00, Z, named TZ)
            parse_datetime_with_tz(s).map(|(date, _, _)| date)
        })
        .map_err(|e| anyhow!("Invalid date format: {}", e))
}

// ============================================================================
// Time Constructors
// ============================================================================

fn eval_time(args: &[Value]) -> Result<Value> {
    if args.is_empty() {
        let now = Utc::now();
        let time = now.time();
        return Ok(Value::Temporal(TemporalValue::Time {
            nanos_since_midnight: time_to_nanos(&time),
            offset_seconds: 0,
        }));
    }

    match &args[0] {
        Value::String(s) => {
            let (time, tz_info) = parse_time_string_with_tz(s)?;
            let offset = match tz_info {
                Some(ref info) => info
                    .offset_for_local(&NaiveDateTime::new(Utc::now().date_naive(), time))?
                    .local_minus_utc(),
                None => 0,
            };
            Ok(Value::Temporal(TemporalValue::Time {
                nanos_since_midnight: time_to_nanos(&time),
                offset_seconds: offset,
            }))
        }
        Value::Temporal(TemporalValue::Time { .. }) => Ok(args[0].clone()),
        // Cross-type: extract time + offset from any temporal
        Value::Temporal(tv) => {
            let time = tv
                .to_time()
                .ok_or_else(|| anyhow!("time(): temporal value has no time component"))?;
            let offset = match tv {
                TemporalValue::DateTime { offset_seconds, .. } => *offset_seconds,
                TemporalValue::Time { offset_seconds, .. } => *offset_seconds,
                _ => 0, // LocalTime, LocalDateTime, Date → UTC
            };
            Ok(Value::Temporal(TemporalValue::Time {
                nanos_since_midnight: time_to_nanos(&time),
                offset_seconds: offset,
            }))
        }
        Value::Map(map) => eval_time_from_map(map, true),
        Value::Null => Ok(Value::Null),
        _ => Err(anyhow!("time() expects a string or map argument")),
    }
}

fn eval_localtime(args: &[Value]) -> Result<Value> {
    if args.is_empty() {
        let now = chrono::Local::now().time();
        return Ok(Value::Temporal(TemporalValue::LocalTime {
            nanos_since_midnight: time_to_nanos(&now),
        }));
    }

    match &args[0] {
        Value::String(s) => {
            let time = parse_time_string(s)?;
            Ok(Value::Temporal(TemporalValue::LocalTime {
                nanos_since_midnight: time_to_nanos(&time),
            }))
        }
        Value::Temporal(TemporalValue::LocalTime { .. }) => Ok(args[0].clone()),
        // Cross-type: extract time from any temporal, strip timezone
        Value::Temporal(tv) => {
            let time = tv
                .to_time()
                .ok_or_else(|| anyhow!("localtime(): temporal value has no time component"))?;
            Ok(Value::Temporal(TemporalValue::LocalTime {
                nanos_since_midnight: time_to_nanos(&time),
            }))
        }
        Value::Map(map) => eval_time_from_map(map, false),
        Value::Null => Ok(Value::Null),
        _ => Err(anyhow!("localtime() expects a string or map argument")),
    }
}

fn eval_time_from_map(map: &HashMap<String, Value>, with_timezone: bool) -> Result<Value> {
    // Check if we have a 'time' field to copy from another time/datetime
    if let Some(time_val) = map.get("time") {
        return eval_time_from_projection(map, time_val, with_timezone);
    }

    let hour = map.get("hour").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
    let minute = map.get("minute").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
    let second = map.get("second").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
    let nanos = build_nanoseconds(map);

    let time = NaiveTime::from_hms_nano_opt(hour, minute, second, nanos).ok_or_else(|| {
        anyhow!(
            "Invalid time: hour={}, minute={}, second={}",
            hour,
            minute,
            second
        )
    })?;

    let nanos = time_to_nanos(&time);

    if with_timezone {
        // Handle timezone for time() if present
        let offset = if let Some(tz_str) = map.get("timezone").and_then(|v| v.as_str()) {
            parse_timezone_offset(tz_str)?
        } else {
            0
        };
        Ok(Value::Temporal(TemporalValue::Time {
            nanos_since_midnight: nanos,
            offset_seconds: offset,
        }))
    } else {
        Ok(Value::Temporal(TemporalValue::LocalTime {
            nanos_since_midnight: nanos,
        }))
    }
}

/// Handle time construction from projection (copying from another temporal value).
fn eval_time_from_projection(
    map: &HashMap<String, Value>,
    source: &Value,
    with_timezone: bool,
) -> Result<Value> {
    // Extract source time and timezone from either Value::Temporal or Value::String
    let (source_time, source_offset) = match source {
        Value::Temporal(TemporalValue::Time {
            nanos_since_midnight,
            offset_seconds,
        }) => (nanos_to_time(*nanos_since_midnight), Some(*offset_seconds)),
        Value::Temporal(TemporalValue::LocalTime {
            nanos_since_midnight,
        }) => (nanos_to_time(*nanos_since_midnight), None),
        Value::Temporal(TemporalValue::DateTime {
            nanos_since_epoch,
            offset_seconds,
            ..
        }) => {
            // Extract time component from DateTime (use local time = UTC nanos + offset)
            let local_nanos = nanos_since_epoch + (*offset_seconds as i64) * 1_000_000_000;
            let dt = chrono::DateTime::from_timestamp_nanos(local_nanos);
            (dt.naive_utc().time(), Some(*offset_seconds))
        }
        Value::Temporal(TemporalValue::LocalDateTime { nanos_since_epoch }) => {
            let dt = chrono::DateTime::from_timestamp_nanos(*nanos_since_epoch);
            (dt.naive_utc().time(), None)
        }
        Value::Temporal(TemporalValue::Date { .. }) => {
            // Date has no time component, use midnight
            (NaiveTime::from_hms_opt(0, 0, 0).unwrap(), None)
        }
        Value::String(s) => {
            let (_, time, tz_info) = parse_datetime_with_tz(s)?;
            let offset = tz_info.as_ref().map(|tz| {
                let today = NaiveDate::from_ymd_opt(2000, 1, 1).unwrap();
                let ndt = NaiveDateTime::new(today, time);
                tz.offset_for_local(&ndt)
                    .map(|o| o.local_minus_utc())
                    .unwrap_or(0)
            });
            (time, offset)
        }
        _ => return Err(anyhow!("time field must be a string or temporal")),
    };

    // Apply overrides from the map
    let hour = map
        .get("hour")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_time.hour());
    let minute = map
        .get("minute")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_time.minute());
    let second = map
        .get("second")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_time.second());

    let nanos = if map.contains_key("millisecond")
        || map.contains_key("microsecond")
        || map.contains_key("nanosecond")
    {
        build_nanoseconds(map)
    } else {
        source_time.nanosecond()
    };

    let time = NaiveTime::from_hms_nano_opt(hour, minute, second, nanos)
        .ok_or_else(|| anyhow!("Invalid time in projection"))?;
    let nanos = time_to_nanos(&time);

    if with_timezone {
        if let Some(tz_str) = map.get("timezone").and_then(|v| v.as_str()) {
            let new_offset = parse_timezone_offset(tz_str)?;
            // If source has a timezone, perform timezone conversion:
            // UTC = local_time - source_offset; new_local = UTC + new_offset
            let converted_nanos = if let Some(src_offset) = source_offset {
                let utc_nanos = nanos - (src_offset as i64) * 1_000_000_000;
                let target_nanos = utc_nanos + (new_offset as i64) * 1_000_000_000;
                // Wrap around within a day
                target_nanos.rem_euclid(NANOS_PER_DAY)
            } else {
                // Source has no timezone (localtime/localdatetime): just assign
                nanos
            };
            Ok(Value::Temporal(TemporalValue::Time {
                nanos_since_midnight: converted_nanos,
                offset_seconds: new_offset,
            }))
        } else {
            let offset = source_offset.unwrap_or(0);
            Ok(Value::Temporal(TemporalValue::Time {
                nanos_since_midnight: nanos,
                offset_seconds: offset,
            }))
        }
    } else {
        Ok(Value::Temporal(TemporalValue::LocalTime {
            nanos_since_midnight: nanos,
        }))
    }
}

fn parse_time_string(s: &str) -> Result<NaiveTime> {
    // Try various time formats
    NaiveTime::parse_from_str(s, "%H:%M:%S")
        .or_else(|_| NaiveTime::parse_from_str(s, "%H:%M:%S%.f"))
        .or_else(|_| NaiveTime::parse_from_str(s, "%H:%M:%S%.9f"))
        .or_else(|_| NaiveTime::parse_from_str(s, "%H:%M"))
        // Try compact time formats (HHMMSS, HHMM, HH) before falling back to datetime parser,
        // since 4-digit strings like "2140" are ambiguous (year vs HHMM).
        .or_else(|e| try_parse_compact_time(s).ok_or(e))
        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%d %H:%M:%S").map(|dt| dt.time()))
        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%d %H:%M:%S%.f").map(|dt| dt.time()))
        .or_else(|_| DateTime::parse_from_rfc3339(s).map(|dt| dt.time()))
        .or_else(|_| {
            // Fallback: use full datetime parser (handles offsets like +01:00, Z, named TZ)
            parse_datetime_with_tz(s).map(|(_, time, _)| time)
        })
        .map_err(|_| anyhow!("Invalid time format"))
}

/// Parse a string as time with timezone, preferring time interpretation over date.
///
/// This is used by `eval_time` where the input is known to be a time value.
/// It handles ambiguous cases like "2140-02" (compact time 21:40 with offset -02:00)
/// that would otherwise be misinterpreted as a date (year 2140, February).
fn parse_time_string_with_tz(s: &str) -> Result<(NaiveTime, Option<TimezoneInfo>)> {
    // Strip bracketed timezone suffix
    let (datetime_part, tz_name) = if let Some(bracket_pos) = s.find('[') {
        let tz_name = s[bracket_pos + 1..s.len() - 1].to_string();
        (&s[..bracket_pos], Some(tz_name))
    } else {
        (s, None)
    };

    // Try plain time formats first (no timezone)
    if let Ok(time) = try_parse_naive_time(datetime_part) {
        let tz_info = tz_name.map(|n| parse_timezone(&n)).transpose()?;
        return Ok((time, tz_info));
    }

    // Try time with Z suffix
    if let Some(base) = datetime_part
        .strip_suffix('Z')
        .or_else(|| datetime_part.strip_suffix('z'))
        && let Ok(time) = try_parse_naive_time(base)
    {
        let utc_tz = TimezoneInfo::FixedOffset(FixedOffset::east_opt(0).unwrap());
        let tz_info = tz_name
            .map(|n| parse_timezone(&n))
            .transpose()?
            .or(Some(utc_tz));
        return Ok((time, tz_info));
    }

    // Try splitting at + or - for timezone offset, preferring time interpretation
    if let Some(tz_pos) = datetime_part.rfind('+').or_else(|| {
        // For time strings, find the last '-' that's after at least HH (pos >= 2)
        datetime_part.rfind('-').filter(|&pos| pos >= 2)
    }) {
        let left_part = &datetime_part[..tz_pos];
        let tz_part = &datetime_part[tz_pos..];

        if let Ok(time) = try_parse_naive_time(left_part) {
            let tz_info = if let Some(name) = tz_name {
                Some(parse_timezone(&name)?)
            } else {
                let offset = parse_timezone_offset(tz_part)?;
                let fo = FixedOffset::east_opt(offset)
                    .ok_or_else(|| anyhow!("Invalid timezone offset"))?;
                Some(TimezoneInfo::FixedOffset(fo))
            };
            return Ok((time, tz_info));
        }
    }

    // Fall back to full datetime parser
    let (_, time, tz_info) = parse_datetime_with_tz(s)?;
    Ok((time, tz_info))
}

fn build_nanoseconds(map: &HashMap<String, Value>) -> u32 {
    let millis = map.get("millisecond").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
    let micros = map.get("microsecond").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
    let nanos = map.get("nanosecond").and_then(|v| v.as_i64()).unwrap_or(0) as u32;

    millis * 1_000_000 + micros * 1_000 + nanos
}

/// Build nanoseconds from map, preserving base value's sub-components when the
/// map doesn't override them. For example, if base_nanos encodes
/// millis=645, micros=876, nanos=123 and map only sets {nanosecond: 2},
/// the result preserves the millis and micros from the base.
fn build_nanoseconds_with_base(map: &HashMap<String, Value>, base_nanos: u32) -> u32 {
    let base_millis = base_nanos / 1_000_000;
    let base_micros = (base_nanos % 1_000_000) / 1_000;
    let base_nano_part = base_nanos % 1_000;

    let millis = map
        .get("millisecond")
        .and_then(|v| v.as_i64())
        .unwrap_or(base_millis as i64) as u32;
    let micros = map
        .get("microsecond")
        .and_then(|v| v.as_i64())
        .unwrap_or(base_micros as i64) as u32;
    let nanos = map
        .get("nanosecond")
        .and_then(|v| v.as_i64())
        .unwrap_or(base_nano_part as i64) as u32;

    millis * 1_000_000 + micros * 1_000 + nanos
}

/// Format timezone offset with optional seconds (e.g., "+01:00" or "+02:05:59").
fn format_timezone_offset(offset_secs: i32) -> String {
    if offset_secs == 0 {
        "Z".to_string()
    } else {
        let hours = offset_secs / 3600;
        let remaining = offset_secs.abs() % 3600;
        let mins = remaining / 60;
        let secs = remaining % 60;
        if secs != 0 {
            format!("{:+03}:{:02}:{:02}", hours, mins, secs)
        } else {
            format!("{:+03}:{:02}", hours, mins)
        }
    }
}

fn format_time_with_nanos(time: &NaiveTime) -> String {
    let nanos = time.nanosecond();
    let secs = time.second();

    if nanos == 0 && secs == 0 {
        // Omit :00 seconds when they're zero
        time.format("%H:%M").to_string()
    } else if nanos == 0 {
        time.format("%H:%M:%S").to_string()
    } else if nanos.is_multiple_of(1_000_000) {
        // Milliseconds only
        time.format("%H:%M:%S%.3f").to_string()
    } else if nanos.is_multiple_of(1_000) {
        // Microseconds
        time.format("%H:%M:%S%.6f").to_string()
    } else {
        // Full nanoseconds
        time.format("%H:%M:%S%.9f").to_string()
    }
}

fn parse_timezone_offset(tz: &str) -> Result<i32> {
    let tz = tz.trim();
    if tz == "Z" || tz == "z" {
        return Ok(0);
    }

    // Must start with + or - and have at least HH (3 chars total)
    if tz.len() >= 3 && (tz.starts_with('+') || tz.starts_with('-')) {
        let sign = if tz.starts_with('-') { -1 } else { 1 };
        let hours: i32 = tz[1..3]
            .parse()
            .map_err(|_| anyhow!("Invalid timezone hours"))?;

        let rest = &tz[3..];
        let (mins, secs) = if rest.is_empty() {
            // +HH (hours-only, e.g., -02)
            (0, 0)
        } else if let Some(after_colon) = rest.strip_prefix(':') {
            // Colon-separated: +HH:MM or +HH:MM:SS
            let mins: i32 = if after_colon.len() >= 2 {
                after_colon[..2]
                    .parse()
                    .map_err(|_| anyhow!("Invalid timezone minutes"))?
            } else {
                0
            };
            let secs: i32 = if after_colon.len() >= 5 && after_colon.as_bytes()[2] == b':' {
                // +HH:MM:SS
                after_colon[3..5]
                    .parse()
                    .map_err(|_| anyhow!("Invalid timezone seconds"))?
            } else {
                0
            };
            (mins, secs)
        } else {
            // Compact no-colon: +HHMM or +HHMMSS
            let mins: i32 = if rest.len() >= 2 {
                rest[..2]
                    .parse()
                    .map_err(|_| anyhow!("Invalid timezone minutes"))?
            } else {
                0
            };
            let secs: i32 = if rest.len() >= 4 {
                rest[2..4]
                    .parse()
                    .map_err(|_| anyhow!("Invalid timezone seconds"))?
            } else {
                0
            };
            (mins, secs)
        };

        return Ok(sign * (hours * 3600 + mins * 60 + secs));
    }

    Err(anyhow!("Unsupported timezone format: {}", tz))
}

// ============================================================================
// Datetime Constructors
// ============================================================================

fn eval_datetime(args: &[Value]) -> Result<Value> {
    if args.is_empty() {
        let now = Utc::now();
        return Ok(Value::Temporal(TemporalValue::DateTime {
            nanos_since_epoch: now.timestamp_nanos_opt().unwrap_or(0),
            offset_seconds: 0,
            timezone_name: None,
        }));
    }

    match &args[0] {
        Value::String(s) => {
            let (date, time, tz_info) = parse_datetime_with_tz(s)?;
            let ndt = NaiveDateTime::new(date, time);
            let (offset_secs, tz_name) = match tz_info {
                Some(ref info) => {
                    let fo = info.offset_for_local(&ndt)?;
                    (fo.local_minus_utc(), info.name().map(|s| s.to_string()))
                }
                None => (0, None),
            };
            Ok(datetime_value_from_local_and_offset(
                &ndt,
                offset_secs,
                tz_name,
            ))
        }
        Value::Temporal(TemporalValue::DateTime { .. }) => Ok(args[0].clone()),
        // Cross-type: convert any temporal to datetime (add UTC timezone)
        Value::Temporal(tv) => {
            let date = tv.to_date().unwrap_or_else(|| Utc::now().date_naive());
            let time = tv
                .to_time()
                .unwrap_or_else(|| NaiveTime::from_hms_opt(0, 0, 0).unwrap());
            let ndt = NaiveDateTime::new(date, time);
            let offset = match tv {
                TemporalValue::Time { offset_seconds, .. } => *offset_seconds,
                _ => 0,
            };
            Ok(datetime_value_from_local_and_offset(&ndt, offset, None))
        }
        Value::Map(map) => eval_datetime_from_map(map, true),
        Value::Null => Ok(Value::Null),
        _ => Err(anyhow!("datetime() expects a string or map argument")),
    }
}

fn eval_localdatetime(args: &[Value]) -> Result<Value> {
    if args.is_empty() {
        let now = chrono::Local::now().naive_local();
        let epoch = NaiveDateTime::new(
            NaiveDate::from_ymd_opt(1970, 1, 1).unwrap(),
            NaiveTime::from_hms_opt(0, 0, 0).unwrap(),
        );
        let nanos = now
            .signed_duration_since(epoch)
            .num_nanoseconds()
            .unwrap_or(0);
        return Ok(Value::Temporal(TemporalValue::LocalDateTime {
            nanos_since_epoch: nanos,
        }));
    }

    match &args[0] {
        Value::String(s) => {
            match parse_datetime_with_tz(s) {
                Ok((date, time, _)) => {
                    let ndt = NaiveDateTime::new(date, time);
                    Ok(localdatetime_value_from_naive(&ndt))
                }
                Err(e) => {
                    if parse_extended_localdatetime_string(s).is_some() {
                        // Out-of-range years cannot fit the current TemporalValue LocalDateTime encoding.
                        Ok(Value::String(s.clone()))
                    } else {
                        Err(e)
                    }
                }
            }
        }
        Value::Temporal(TemporalValue::LocalDateTime { .. }) => Ok(args[0].clone()),
        // Cross-type: extract date+time, strip timezone
        Value::Temporal(tv) => {
            let date = tv.to_date().unwrap_or_else(|| Utc::now().date_naive());
            let time = tv
                .to_time()
                .unwrap_or_else(|| NaiveTime::from_hms_opt(0, 0, 0).unwrap());
            let ndt = NaiveDateTime::new(date, time);
            Ok(localdatetime_value_from_naive(&ndt))
        }
        Value::Map(map) => eval_datetime_from_map(map, false),
        Value::Null => Ok(Value::Null),
        _ => Err(anyhow!("localdatetime() expects a string or map argument")),
    }
}

/// Extract time and optional timezone info from a Value (temporal or string).
fn extract_time_and_tz_from_value(val: &Value) -> Result<(NaiveTime, Option<TimezoneInfo>)> {
    match val {
        Value::Temporal(tv) => {
            let time = tv
                .to_time()
                .unwrap_or_else(|| NaiveTime::from_hms_opt(0, 0, 0).unwrap());
            let tz = match tv {
                TemporalValue::DateTime {
                    offset_seconds,
                    timezone_name,
                    ..
                } => {
                    if let Some(name) = timezone_name {
                        Some(parse_timezone(name)?)
                    } else {
                        let fo = FixedOffset::east_opt(*offset_seconds)
                            .ok_or_else(|| anyhow!("Invalid offset"))?;
                        Some(TimezoneInfo::FixedOffset(fo))
                    }
                }
                TemporalValue::Time { offset_seconds, .. } => {
                    let fo = FixedOffset::east_opt(*offset_seconds)
                        .ok_or_else(|| anyhow!("Invalid offset"))?;
                    Some(TimezoneInfo::FixedOffset(fo))
                }
                _ => None,
            };
            Ok((time, tz))
        }
        Value::String(s) => {
            let (_, time, tz_info) = parse_datetime_with_tz(s)?;
            Ok((time, tz_info))
        }
        _ => Err(anyhow!("time must be a string or temporal")),
    }
}

/// Convert NaiveDateTime to nanoseconds since Unix epoch.
/// Returns None when the value is outside i64 nanosecond range.
fn naive_datetime_to_nanos(ndt: &NaiveDateTime) -> Option<i64> {
    let epoch = NaiveDateTime::new(
        NaiveDate::from_ymd_opt(1970, 1, 1).unwrap(),
        NaiveTime::from_hms_opt(0, 0, 0).unwrap(),
    );
    ndt.signed_duration_since(epoch).num_nanoseconds()
}

fn localdatetime_value_from_naive(ndt: &NaiveDateTime) -> Value {
    if let Some(nanos) = naive_datetime_to_nanos(ndt) {
        Value::Temporal(TemporalValue::LocalDateTime {
            nanos_since_epoch: nanos,
        })
    } else {
        Value::String(format_naive_datetime(ndt))
    }
}

fn datetime_value_from_local_and_offset(
    local_ndt: &NaiveDateTime,
    offset_seconds: i32,
    timezone_name: Option<String>,
) -> Value {
    let utc_ndt = *local_ndt - Duration::seconds(offset_seconds as i64);
    let utc_dt = DateTime::<Utc>::from_naive_utc_and_offset(utc_ndt, Utc);

    if let Some(nanos) = utc_dt.timestamp_nanos_opt() {
        Value::Temporal(TemporalValue::DateTime {
            nanos_since_epoch: nanos,
            offset_seconds,
            timezone_name,
        })
    } else {
        let rendered = if let Some(offset) = FixedOffset::east_opt(offset_seconds) {
            if let Some(dt) = offset.from_local_datetime(local_ndt).single() {
                format_datetime_with_offset_and_tz(&dt, timezone_name.as_deref())
            } else {
                let base = format!(
                    "{}{}",
                    format_naive_datetime(local_ndt),
                    format_timezone_offset(offset_seconds)
                );
                if let Some(name) = timezone_name.as_deref() {
                    format!("{base}[{name}]")
                } else {
                    base
                }
            }
        } else {
            let base = format!(
                "{}{}",
                format_naive_datetime(local_ndt),
                format_timezone_offset(offset_seconds)
            );
            if let Some(name) = timezone_name.as_deref() {
                format!("{base}[{name}]")
            } else {
                base
            }
        };
        Value::String(rendered)
    }
}

fn eval_datetime_from_map(map: &HashMap<String, Value>, with_timezone: bool) -> Result<Value> {
    // Check if we have a 'datetime' field to copy from another datetime
    if let Some(dt_val) = map.get("datetime") {
        return eval_datetime_from_projection(map, dt_val, with_timezone);
    }

    // When both 'date' and 'time' keys are present, combine them
    if let (Some(date_val), Some(time_val)) = (map.get("date"), map.get("time")) {
        return eval_datetime_from_date_and_time(map, date_val, time_val, with_timezone);
    }

    // date-only projection: date from source, time from explicit map fields.
    // Unlike `datetime` projection, we do NOT inherit timezone from the date source —
    // it defaults to UTC unless an explicit `timezone` key is present.
    if let Some(date_val) = map.get("date") {
        let source_date = temporal_or_string_to_date(date_val)?;
        let date = build_date_from_projection(map, &source_date)?;
        let hour = map.get("hour").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
        let minute = map.get("minute").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
        let second = map.get("second").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
        let nanos = build_nanoseconds(map);
        let time = NaiveTime::from_hms_nano_opt(hour, minute, second, nanos)
            .ok_or_else(|| anyhow!("Invalid time in datetime map"))?;
        let ndt = NaiveDateTime::new(date, time);

        if with_timezone {
            let (offset_secs, tz_name) =
                if let Some(tz_str) = map.get("timezone").and_then(|v| v.as_str()) {
                    let tz_info = parse_timezone(tz_str)?;
                    let offset = tz_info.offset_for_local(&ndt)?;
                    (
                        offset.local_minus_utc(),
                        tz_info.name().map(|s| s.to_string()),
                    )
                } else {
                    (0, None) // Default to UTC, not source tz
                };

            return Ok(datetime_value_from_local_and_offset(
                &ndt,
                offset_secs,
                tz_name,
            ));
        } else {
            return Ok(localdatetime_value_from_naive(&ndt));
        }
    }

    // Build time part: if 'time' key is present, extract from temporal/string;
    // otherwise build from explicit hour/minute/second fields.
    let (time, source_tz) = if let Some(time_val) = map.get("time") {
        let (t, tz) = extract_time_and_tz_from_value(time_val)?;
        // Apply overrides from map (hour, minute, second, etc.)
        let hour = map
            .get("hour")
            .and_then(|v| v.as_i64())
            .map(|v| v as u32)
            .unwrap_or(t.hour());
        let minute = map
            .get("minute")
            .and_then(|v| v.as_i64())
            .map(|v| v as u32)
            .unwrap_or(t.minute());
        let second = map
            .get("second")
            .and_then(|v| v.as_i64())
            .map(|v| v as u32)
            .unwrap_or(t.second());
        let nanos = if map.contains_key("millisecond")
            || map.contains_key("microsecond")
            || map.contains_key("nanosecond")
        {
            build_nanoseconds(map)
        } else {
            t.nanosecond()
        };
        let resolved_time = NaiveTime::from_hms_nano_opt(hour, minute, second, nanos)
            .ok_or_else(|| anyhow!("Invalid time in datetime map"))?;
        (resolved_time, tz)
    } else {
        let hour = map.get("hour").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
        let minute = map.get("minute").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
        let second = map.get("second").and_then(|v| v.as_i64()).unwrap_or(0) as u32;
        let nanos = build_nanoseconds(map);
        let t = NaiveTime::from_hms_nano_opt(hour, minute, second, nanos)
            .ok_or_else(|| anyhow!("Invalid time in datetime map"))?;
        (t, None::<TimezoneInfo>)
    };

    // Build date part - support multiple construction modes
    let date = build_date_from_map(map)?;

    let ndt = NaiveDateTime::new(date, time);

    if with_timezone {
        // Handle timezone: explicit > from time source > UTC default
        // When source has a timezone and a different explicit timezone is given,
        // perform timezone conversion (source_local → UTC → target_local).
        if let Some(tz_str) = map.get("timezone").and_then(|v| v.as_str()) {
            let tz_info = parse_timezone(tz_str)?;
            if let Some(ref src_tz) = source_tz {
                // Timezone CONVERSION: source local → UTC → target local
                let src_offset = src_tz.offset_for_local(&ndt)?;
                let utc_ndt = ndt - Duration::seconds(src_offset.local_minus_utc() as i64);
                let target_offset = tz_info.offset_for_utc(&utc_ndt);
                let offset_secs = target_offset.local_minus_utc();
                let tz_name = tz_info.name().map(|s| s.to_string());
                let target_local_ndt = utc_ndt + Duration::seconds(offset_secs as i64);
                Ok(datetime_value_from_local_and_offset(
                    &target_local_ndt,
                    offset_secs,
                    tz_name,
                ))
            } else {
                // Source has no timezone: just assign target timezone
                let offset = tz_info.offset_for_local(&ndt)?;
                let offset_secs = offset.local_minus_utc();
                let tz_name = tz_info.name().map(|s| s.to_string());
                Ok(datetime_value_from_local_and_offset(
                    &ndt,
                    offset_secs,
                    tz_name,
                ))
            }
        } else if let Some(ref tz) = source_tz {
            let offset = tz.offset_for_local(&ndt)?;
            let offset_secs = offset.local_minus_utc();
            let tz_name = tz.name().map(|s| s.to_string());
            Ok(datetime_value_from_local_and_offset(
                &ndt,
                offset_secs,
                tz_name,
            ))
        } else {
            // No timezone at all: default to UTC
            Ok(datetime_value_from_local_and_offset(&ndt, 0, None))
        }
    } else {
        // localdatetime - no timezone
        Ok(localdatetime_value_from_naive(&ndt))
    }
}

/// Handle datetime construction from separate date and time sources.
///
/// Cypher: `datetime({date: dateVal, time: timeVal, ...overrides})`
/// Extracts date component from dateVal, time + tz from timeVal, then applies overrides.
fn eval_datetime_from_date_and_time(
    map: &HashMap<String, Value>,
    date_val: &Value,
    time_val: &Value,
    with_timezone: bool,
) -> Result<Value> {
    let source_date = temporal_or_string_to_date(date_val)?;
    let (source_time, source_tz) = match time_val {
        Value::Temporal(tv) => {
            let time = tv
                .to_time()
                .unwrap_or_else(|| NaiveTime::from_hms_opt(0, 0, 0).unwrap());
            let tz = match tv {
                TemporalValue::DateTime {
                    offset_seconds,
                    timezone_name,
                    ..
                } => {
                    if let Some(name) = timezone_name {
                        Some(parse_timezone(name)?)
                    } else {
                        let fo = FixedOffset::east_opt(*offset_seconds)
                            .ok_or_else(|| anyhow!("Invalid offset"))?;
                        Some(TimezoneInfo::FixedOffset(fo))
                    }
                }
                TemporalValue::Time { offset_seconds, .. } => {
                    let fo = FixedOffset::east_opt(*offset_seconds)
                        .ok_or_else(|| anyhow!("Invalid offset"))?;
                    Some(TimezoneInfo::FixedOffset(fo))
                }
                _ => None,
            };
            (time, tz)
        }
        Value::String(s) => {
            let (_, time, tz_info) = parse_datetime_with_tz(s)?;
            (time, tz_info)
        }
        _ => return Err(anyhow!("time field must be a string or temporal")),
    };

    // Build date from projection overrides
    let date = build_date_from_projection(map, &source_date)?;

    // Build time from overrides
    let hour = map
        .get("hour")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_time.hour());
    let minute = map
        .get("minute")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_time.minute());
    let second = map
        .get("second")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_time.second());

    let nanos = if map.contains_key("millisecond")
        || map.contains_key("microsecond")
        || map.contains_key("nanosecond")
    {
        build_nanoseconds(map)
    } else {
        source_time.nanosecond()
    };

    let time = NaiveTime::from_hms_nano_opt(hour, minute, second, nanos)
        .ok_or_else(|| anyhow!("Invalid time in datetime(date+time) projection"))?;

    let ndt = NaiveDateTime::new(date, time);

    if with_timezone {
        if let Some(tz_str) = map.get("timezone").and_then(|v| v.as_str()) {
            let tz_info = parse_timezone(tz_str)?;
            if let Some(ref src_tz) = source_tz {
                // Timezone CONVERSION: source local → UTC → target local
                let src_offset = src_tz.offset_for_local(&ndt)?;
                let utc_ndt = ndt - Duration::seconds(src_offset.local_minus_utc() as i64);
                let target_offset = tz_info.offset_for_utc(&utc_ndt);
                let offset_secs = target_offset.local_minus_utc();
                let tz_name = tz_info.name().map(|s| s.to_string());
                let target_local_ndt = utc_ndt + Duration::seconds(offset_secs as i64);
                Ok(datetime_value_from_local_and_offset(
                    &target_local_ndt,
                    offset_secs,
                    tz_name,
                ))
            } else {
                // Source has no timezone: just assign target timezone
                let offset = tz_info.offset_for_local(&ndt)?;
                let offset_secs = offset.local_minus_utc();
                let tz_name = tz_info.name().map(|s| s.to_string());
                Ok(datetime_value_from_local_and_offset(
                    &ndt,
                    offset_secs,
                    tz_name,
                ))
            }
        } else if let Some(ref tz) = source_tz {
            let offset = tz.offset_for_local(&ndt)?;
            let offset_secs = offset.local_minus_utc();
            let tz_name = tz.name().map(|s| s.to_string());
            Ok(datetime_value_from_local_and_offset(
                &ndt,
                offset_secs,
                tz_name,
            ))
        } else {
            // No timezone at all: default to UTC
            Ok(datetime_value_from_local_and_offset(&ndt, 0, None))
        }
    } else {
        Ok(localdatetime_value_from_naive(&ndt))
    }
}

/// Handle datetime construction from projection (copying from another temporal value).
fn eval_datetime_from_projection(
    map: &HashMap<String, Value>,
    source: &Value,
    with_timezone: bool,
) -> Result<Value> {
    // Extract source components from either Value::Temporal or Value::String
    let (source_date, source_time, source_tz) = temporal_or_string_to_components(source)?;

    // Build date portion using shared helper
    let date = build_date_from_projection(map, &source_date)?;

    // Build time portion
    let hour = map
        .get("hour")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_time.hour());
    let minute = map
        .get("minute")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_time.minute());
    let second = map
        .get("second")
        .and_then(|v| v.as_i64())
        .map(|v| v as u32)
        .unwrap_or(source_time.second());

    // Sub-seconds are inherited from source unless explicitly overridden.
    // When constructing via `datetime` key, overriding second/minute/hour
    // still preserves sub-seconds from the source (per TCK Temporal3).
    let nanos = if map.contains_key("millisecond")
        || map.contains_key("microsecond")
        || map.contains_key("nanosecond")
    {
        build_nanoseconds(map)
    } else {
        source_time.nanosecond()
    };

    let time = NaiveTime::from_hms_nano_opt(hour, minute, second, nanos)
        .ok_or_else(|| anyhow!("Invalid time in projection"))?;

    let ndt = NaiveDateTime::new(date, time);

    if with_timezone {
        if let Some(tz_str) = map.get("timezone").and_then(|v| v.as_str()) {
            let tz_info = parse_timezone(tz_str)?;
            if let Some(ref src_tz) = source_tz {
                // Timezone CONVERSION: source local → UTC → target local
                let src_offset = src_tz.offset_for_local(&ndt)?;
                let utc_ndt = ndt - Duration::seconds(src_offset.local_minus_utc() as i64);
                let target_offset = tz_info.offset_for_utc(&utc_ndt);
                let offset_secs = target_offset.local_minus_utc();
                let tz_name = tz_info.name().map(|s| s.to_string());
                let target_local_ndt = utc_ndt + Duration::seconds(offset_secs as i64);
                Ok(datetime_value_from_local_and_offset(
                    &target_local_ndt,
                    offset_secs,
                    tz_name,
                ))
            } else {
                // Source has no timezone: just assign
                let offset = tz_info.offset_for_local(&ndt)?;
                let offset_secs = offset.local_minus_utc();
                let tz_name = tz_info.name().map(|s| s.to_string());
                Ok(datetime_value_from_local_and_offset(
                    &ndt,
                    offset_secs,
                    tz_name,
                ))
            }
        } else if let Some(ref tz) = source_tz {
            let offset = tz.offset_for_local(&ndt)?;
            let offset_secs = offset.local_minus_utc();
            let tz_name = tz.name().map(|s| s.to_string());
            Ok(datetime_value_from_local_and_offset(
                &ndt,
                offset_secs,
                tz_name,
            ))
        } else {
            // No timezone: default to UTC
            Ok(datetime_value_from_local_and_offset(&ndt, 0, None))
        }
    } else {
        Ok(localdatetime_value_from_naive(&ndt))
    }
}

/// Extract date, time, and timezone from either Value::Temporal or Value::String.
fn temporal_or_string_to_components(
    val: &Value,
) -> Result<(NaiveDate, NaiveTime, Option<TimezoneInfo>)> {
    match val {
        Value::Temporal(tv) => {
            let date = tv.to_date().unwrap_or_else(|| Utc::now().date_naive());
            let time = tv
                .to_time()
                .unwrap_or_else(|| NaiveTime::from_hms_opt(0, 0, 0).unwrap());
            let tz_info = match tv {
                TemporalValue::DateTime {
                    offset_seconds,
                    timezone_name,
                    ..
                } => {
                    if let Some(name) = timezone_name {
                        Some(parse_timezone(name)?)
                    } else {
                        let fo = FixedOffset::east_opt(*offset_seconds)
                            .ok_or_else(|| anyhow!("Invalid offset"))?;
                        Some(TimezoneInfo::FixedOffset(fo))
                    }
                }
                TemporalValue::Time { offset_seconds, .. } => {
                    let fo = FixedOffset::east_opt(*offset_seconds)
                        .ok_or_else(|| anyhow!("Invalid offset"))?;
                    Some(TimezoneInfo::FixedOffset(fo))
                }
                _ => None,
            };
            Ok((date, time, tz_info))
        }
        Value::String(s) => parse_datetime_with_tz(s),
        _ => Err(anyhow!("Expected temporal or string value")),
    }
}

/// Convert a 1-based ISO weekday number (1=Mon, 7=Sun) to a `chrono::Weekday`.
fn iso_weekday(d: u32) -> Option<Weekday> {
    match d {
        1 => Some(Weekday::Mon),
        2 => Some(Weekday::Tue),
        3 => Some(Weekday::Wed),
        4 => Some(Weekday::Thu),
        5 => Some(Weekday::Fri),
        6 => Some(Weekday::Sat),
        7 => Some(Weekday::Sun),
        _ => None,
    }
}

/// Try parsing an ISO 8601 date string (compact or with separators).
///
/// Supports:
/// - `YYYYMMDD` (8 digits, e.g., `19840711` -> 1984-07-11)
/// - `YYYYDDD`  (7 digits, e.g., `1984183` -> ordinal day 183 of 1984)
/// - `YYYYMM`   (6 digits, e.g., `201507` -> 2015-07-01)
/// - `YYYY`     (4 digits, e.g., `2015` -> 2015-01-01)
/// - `YYYYWww`  (e.g., `1984W30` -> Monday of ISO week 30 of 1984)
/// - `YYYYWwwD` (e.g., `1984W305` -> day 5 of ISO week 30 of 1984)
/// - `YYYY-Www-D` / `YYYY-Www` (separator ISO week dates)
/// - `YYYY-DDD` (separator ordinal date)
/// - `YYYY-MM`  (separator year-month)
fn try_parse_compact_date(s: &str) -> Option<NaiveDate> {
    // 1. Separator ISO week dates: YYYY-Www-D (10 chars) or YYYY-Www (8 chars)
    if let Some(w_pos) = s.find("-W") {
        if w_pos == 4 {
            let year: i32 = s[..4].parse().ok()?;
            let after_w = &s[w_pos + 2..]; // skip "-W"
            // YYYY-Www-D (exactly 4 chars after W: "ww-D")
            if after_w.len() == 4 && after_w.as_bytes()[2] == b'-' {
                let week: u32 = after_w[..2].parse().ok()?;
                let d: u32 = after_w[3..4].parse().ok()?;
                let weekday = iso_weekday(d)?;
                return NaiveDate::from_isoywd_opt(year, week, weekday);
            }
            // YYYY-Www (exactly 2 chars after W: "ww")
            if after_w.len() == 2 && after_w.chars().all(|c| c.is_ascii_digit()) {
                let week: u32 = after_w.parse().ok()?;
                return NaiveDate::from_isoywd_opt(year, week, Weekday::Mon);
            }
        }
        return None;
    }

    // 2. Compact ISO week dates: YYYYWww or YYYYWwwD
    if let Some(w_pos) = s.find('W') {
        if w_pos == 4 && s.len() >= 7 {
            let year: i32 = s[..4].parse().ok()?;
            let after_w = &s[w_pos + 1..];
            if after_w.len() == 2 || after_w.len() == 3 {
                let week: u32 = after_w[..2].parse().ok()?;
                let weekday = if after_w.len() == 3 {
                    let d: u32 = after_w[2..3].parse().ok()?;
                    iso_weekday(d)?
                } else {
                    Weekday::Mon
                };
                return NaiveDate::from_isoywd_opt(year, week, weekday);
            }
        }
        return None;
    }

    // 3. Separator formats with dash (no W present)
    if s.len() >= 7 && s.as_bytes()[4] == b'-' && s[..4].chars().all(|c| c.is_ascii_digit()) {
        let year: i32 = s[..4].parse().ok()?;
        let after_dash = &s[5..];

        // YYYY-DDD (separator ordinal date): 3 trailing digits, total 8 chars
        if after_dash.len() == 3 && after_dash.chars().all(|c| c.is_ascii_digit()) {
            let ordinal: u32 = after_dash.parse().ok()?;
            return NaiveDate::from_yo_opt(year, ordinal);
        }

        // YYYY-MM (separator year-month): 2 trailing digits, total 7 chars
        if after_dash.len() == 2 && after_dash.chars().all(|c| c.is_ascii_digit()) {
            let month: u32 = after_dash.parse().ok()?;
            return NaiveDate::from_ymd_opt(year, month, 1);
        }
    }

    // 4. All-digit compact formats
    if !s.chars().all(|c| c.is_ascii_digit()) {
        return None;
    }

    match s.len() {
        // YYYYMMDD
        8 => {
            let year: i32 = s[..4].parse().ok()?;
            let month: u32 = s[4..6].parse().ok()?;
            let day: u32 = s[6..8].parse().ok()?;
            NaiveDate::from_ymd_opt(year, month, day)
        }
        // YYYYDDD (ordinal date)
        7 => {
            let year: i32 = s[..4].parse().ok()?;
            let ordinal: u32 = s[4..7].parse().ok()?;
            NaiveDate::from_yo_opt(year, ordinal)
        }
        // YYYYMM (compact year-month)
        6 => {
            let year: i32 = s[..4].parse().ok()?;
            let month: u32 = s[4..6].parse().ok()?;
            NaiveDate::from_ymd_opt(year, month, 1)
        }
        // YYYY (year only)
        4 => {
            let year: i32 = s.parse().ok()?;
            NaiveDate::from_ymd_opt(year, 1, 1)
        }
        _ => None,
    }
}

/// Try parsing a compact ISO 8601 time string (no colon separators).
///
/// Supports:
/// - `HHMMSS`       (6 digits, e.g., `143000` -> 14:30:00)
/// - `HHMMSS.fff..` (6 digits + fractional, e.g., `143000.123456789` -> 14:30:00.123456789)
/// - `HHMM`         (4 digits, e.g., `1430` -> 14:30:00)
fn try_parse_compact_time(s: &str) -> Option<NaiveTime> {
    // Split on '.' for fractional seconds
    let (integer_part, frac_part) = if let Some(dot_pos) = s.find('.') {
        (&s[..dot_pos], Some(&s[dot_pos + 1..]))
    } else {
        (s, None)
    };

    // Integer part must be all digits
    if !integer_part.chars().all(|c| c.is_ascii_digit()) {
        return None;
    }

    match integer_part.len() {
        // HHMMSS or HHMMSS.fff
        6 => {
            let hour: u32 = integer_part[..2].parse().ok()?;
            let min: u32 = integer_part[2..4].parse().ok()?;
            let sec: u32 = integer_part[4..6].parse().ok()?;
            if let Some(frac) = frac_part {
                // Parse fractional seconds up to nanosecond precision
                // Pad or truncate to 9 digits for nanoseconds
                let mut frac_str = frac.to_string();
                if frac_str.len() > 9 {
                    frac_str.truncate(9);
                }
                while frac_str.len() < 9 {
                    frac_str.push('0');
                }
                let nanos: u32 = frac_str.parse().ok()?;
                NaiveTime::from_hms_nano_opt(hour, min, sec, nanos)
            } else {
                NaiveTime::from_hms_opt(hour, min, sec)
            }
        }
        // HHMM
        4 => {
            if frac_part.is_some() {
                return None; // HHMM.fff doesn't make sense
            }
            let hour: u32 = integer_part[..2].parse().ok()?;
            let min: u32 = integer_part[2..4].parse().ok()?;
            NaiveTime::from_hms_opt(hour, min, 0)
        }
        // HH (hour only)
        2 => {
            if frac_part.is_some() {
                return None; // HH.fff doesn't make sense
            }
            let hour: u32 = integer_part.parse().ok()?;
            NaiveTime::from_hms_opt(hour, 0, 0)
        }
        _ => None,
    }
}

/// Try parsing a string as a NaiveTime using common formats (%H:%M:%S%.f, %H:%M:%S, %H:%M),
/// with fallback to compact ISO 8601 formats (HHMMSS, HHMMSS.fff, HHMM).
fn try_parse_naive_time(s: &str) -> Result<NaiveTime, chrono::ParseError> {
    NaiveTime::parse_from_str(s, "%H:%M:%S%.f")
        .or_else(|_| NaiveTime::parse_from_str(s, "%H:%M:%S"))
        .or_else(|_| NaiveTime::parse_from_str(s, "%H:%M"))
        .or_else(|e| try_parse_compact_time(s).ok_or(e))
}

/// Try parsing a string as a NaiveDateTime using common ISO formats,
/// with fallback to compact ISO 8601 formats (e.g., `19840711T143000`).
fn try_parse_naive_datetime(s: &str) -> Result<NaiveDateTime, chrono::ParseError> {
    NaiveDateTime::parse_from_str(s, "%Y-%m-%dT%H:%M:%S")
        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%dT%H:%M:%S%.f"))
        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%dT%H:%M"))
        .or_else(|e| {
            // Compact datetime: split on 'T' and parse date/time with compact rules
            if let Some(t_pos) = s.find('T') {
                let date_part = &s[..t_pos];
                let time_part = &s[t_pos + 1..];
                let date = try_parse_compact_date(date_part);
                let time = try_parse_compact_time(time_part)
                    .or_else(|| try_parse_naive_time(time_part).ok());
                if let (Some(d), Some(t)) = (date, time) {
                    return Ok(d.and_time(t));
                }
            }
            // Compact date only (no T): parse as date at midnight
            if let Some(date) = try_parse_compact_date(s) {
                let midnight = NaiveTime::from_hms_opt(0, 0, 0).unwrap();
                return Ok(date.and_time(midnight));
            }
            Err(e)
        })
}

/// Parse a datetime string and extract date, time, and timezone info.
pub fn parse_datetime_with_tz(s: &str) -> Result<(NaiveDate, NaiveTime, Option<TimezoneInfo>)> {
    let midnight = NaiveTime::from_hms_opt(0, 0, 0).unwrap();
    let today = Utc::now().date_naive();

    // Check for named timezone suffix like [Europe/Stockholm]
    let (datetime_part, tz_name) = if let Some(bracket_pos) = s.find('[') {
        let tz_name = s[bracket_pos + 1..s.len() - 1].to_string();
        (&s[..bracket_pos], Some(tz_name))
    } else {
        (s, None)
    };

    // Try parsing as full datetime with timezone
    if let Ok(dt) = DateTime::parse_from_rfc3339(datetime_part) {
        let tz_info = if let Some(name) = tz_name {
            Some(parse_timezone(&name)?)
        } else {
            Some(TimezoneInfo::FixedOffset(dt.offset().fix()))
        };
        return Ok((dt.date_naive(), dt.time(), tz_info));
    }

    // Try various datetime formats
    if let Ok(ndt) = try_parse_naive_datetime(datetime_part) {
        let tz_info = tz_name.map(|n| parse_timezone(&n)).transpose()?;
        return Ok((ndt.date(), ndt.time(), tz_info));
    }

    // Date only
    if let Ok(d) = NaiveDate::parse_from_str(datetime_part, "%Y-%m-%d") {
        let tz_info = tz_name.map(|n| parse_timezone(&n)).transpose()?;
        return Ok((d, midnight, tz_info));
    }

    // Compact date formats (YYYYMMDD, YYYYDDD, YYYYWww, YYYYWwwD)
    if let Some(d) = try_parse_compact_date(datetime_part) {
        let tz_info = tz_name.map(|n| parse_timezone(&n)).transpose()?;
        return Ok((d, midnight, tz_info));
    }

    // Try parsing as datetime or time with non-RFC3339 timezone offset
    // (e.g., "2015-07-21T21:40:32.142+0100" or "12:31:14.645876123+01:00")
    //
    // By this point, all date-only formats (YYYY-MM-DD, YYYY-MM, YYYY-DDD, etc.)
    // have already been tried and rejected. Only time-with-offset or
    // datetime-with-offset strings reach here.
    if let Some(tz_pos) = datetime_part.rfind('+').or_else(|| {
        // Find the last '-' that's part of timezone, not date.
        // The minimum before a timezone offset is HH (2 chars for time-only)
        // or T + HH (3 chars after T for datetime).
        datetime_part.rfind('-').filter(|&pos| {
            if let Some(t_pos) = datetime_part.find('T') {
                // Datetime: '-' must be at least T + HH after T
                pos >= t_pos + 3
            } else {
                // Time-only: '-' must be after at least HH
                pos >= 2
            }
        })
    }) {
        let left_part = &datetime_part[..tz_pos];
        let tz_part = &datetime_part[tz_pos..];

        let resolve_tz = |tz_name: Option<String>, tz_part: &str| -> Result<Option<TimezoneInfo>> {
            if let Some(name) = tz_name {
                Ok(Some(parse_timezone(&name)?))
            } else {
                let offset = parse_timezone_offset(tz_part)?;
                let fo = FixedOffset::east_opt(offset)
                    .ok_or_else(|| anyhow!("Invalid timezone offset"))?;
                Ok(Some(TimezoneInfo::FixedOffset(fo)))
            }
        };

        // Try parsing the left part as time first (for short strings like "2140", "21",
        // "21:40", etc. that could be ambiguous with compact dates like YYYY).
        // Only try time-first when there's no 'T' separator (pure time+offset).
        if !left_part.contains('T')
            && let Ok(time) = try_parse_naive_time(left_part)
            && let Ok(tz_info) = resolve_tz(tz_name.clone(), tz_part)
        {
            return Ok((today, time, tz_info));
        }

        // Try parsing the left part as a full datetime
        if let Ok(ndt) = try_parse_naive_datetime(left_part) {
            let tz_info = resolve_tz(tz_name, tz_part)?;
            return Ok((ndt.date(), ndt.time(), tz_info));
        }

        // Try parsing the left part as time only (when datetime attempt failed)
        if left_part.contains('T')
            && let Ok(time) = try_parse_naive_time(left_part)
        {
            let tz_info = resolve_tz(tz_name, tz_part)?;
            return Ok((today, time, tz_info));
        }
    }

    // Try parsing datetime or time with Z suffix
    if let Some(base) = datetime_part
        .strip_suffix('Z')
        .or_else(|| datetime_part.strip_suffix('z'))
    {
        let utc_tz = Some(TimezoneInfo::FixedOffset(FixedOffset::east_opt(0).unwrap()));
        // Try as datetime first (e.g., "2015-W30-2T214032.142Z")
        if let Ok(ndt) = try_parse_naive_datetime(base) {
            let tz_info = tz_name.map(|n| parse_timezone(&n)).transpose()?.or(utc_tz);
            return Ok((ndt.date(), ndt.time(), tz_info));
        }
        // Try as time only
        if let Ok(time) = try_parse_naive_time(base) {
            let tz_info = tz_name.map(|n| parse_timezone(&n)).transpose()?.or(utc_tz);
            return Ok((today, time, tz_info));
        }
    }

    // Try parsing as plain time (no timezone offset, e.g., "14:30" or "12:31:14.645876123")
    if let Ok(time) = try_parse_naive_time(datetime_part) {
        let tz_info = tz_name.map(|n| parse_timezone(&n)).transpose()?;
        return Ok((today, time, tz_info));
    }

    Err(anyhow!("Cannot parse datetime: {}", s))
}

/// Select the chrono format string for the time portion based on nanosecond precision.
fn nanos_precision_format(nanos: u32, seconds: u32) -> &'static str {
    if nanos == 0 && seconds == 0 {
        "%Y-%m-%dT%H:%M"
    } else if nanos == 0 {
        "%Y-%m-%dT%H:%M:%S"
    } else if nanos.is_multiple_of(1_000_000) {
        "%Y-%m-%dT%H:%M:%S%.3f"
    } else if nanos.is_multiple_of(1_000) {
        "%Y-%m-%dT%H:%M:%S%.6f"
    } else {
        "%Y-%m-%dT%H:%M:%S%.9f"
    }
}

fn format_datetime_with_nanos(dt: &DateTime<Utc>) -> String {
    let fmt = nanos_precision_format(dt.nanosecond(), dt.second());
    format!("{}Z", dt.format(fmt))
}

fn format_datetime_with_offset_and_tz(dt: &DateTime<FixedOffset>, tz_name: Option<&str>) -> String {
    let fmt = nanos_precision_format(dt.nanosecond(), dt.second());
    let tz_suffix = format_timezone_offset(dt.offset().local_minus_utc());
    let base = format!("{}{}", dt.format(fmt), tz_suffix);

    if let Some(name) = tz_name {
        format!("{}[{}]", base, name)
    } else {
        base
    }
}

fn format_naive_datetime(ndt: &NaiveDateTime) -> String {
    let fmt = nanos_precision_format(ndt.nanosecond(), ndt.second());
    ndt.format(fmt).to_string()
}

// ============================================================================
// CypherDuration for ISO 8601 formatting
// ============================================================================

/// Represents a Cypher duration with separate month, day, and nanosecond components.
///
/// This allows proper ISO 8601 formatting without loss of calendar semantics.
#[derive(Debug, Clone, PartialEq)]
pub struct CypherDuration {
    /// Months (includes years * 12)
    pub months: i64,
    /// Days (includes weeks * 7)
    pub days: i64,
    /// Nanoseconds (time portion only, excludes days)
    pub nanos: i64,
}

impl CypherDuration {
    pub fn new(months: i64, days: i64, nanos: i64) -> Self {
        Self {
            months,
            days,
            nanos,
        }
    }

    /// Convert this duration to a `Value::Temporal(TemporalValue::Duration)`.
    pub fn to_temporal_value(&self) -> Value {
        Value::Temporal(TemporalValue::Duration {
            months: self.months,
            days: self.days,
            nanos: self.nanos,
        })
    }

    /// Create from total microseconds (loses calendar semantics).
    pub fn from_micros(micros: i64) -> Self {
        let total_nanos = micros * 1000;
        let total_secs = total_nanos / NANOS_PER_SECOND;
        let remaining_nanos = total_nanos % NANOS_PER_SECOND;

        let days = total_secs / (24 * 3600);
        let day_secs = total_secs % (24 * 3600);

        Self {
            months: 0,
            days,
            nanos: day_secs * NANOS_PER_SECOND + remaining_nanos,
        }
    }

    /// Format as ISO 8601 duration string.
    ///
    /// Handles negative components and mixed-sign seconds/nanoseconds correctly.
    pub fn to_iso8601(&self) -> String {
        let mut result = String::from("P");

        let years = self.months / 12;
        let months = self.months % 12;

        if years != 0 {
            result.push_str(&format!("{}Y", years));
        }
        if months != 0 {
            result.push_str(&format!("{}M", months));
        }
        if self.days != 0 {
            result.push_str(&format!("{}D", self.days));
        }

        // Time part: use truncating division (towards zero) so each component
        // independently carries its sign, matching Neo4j's format.
        let nanos = self.nanos;
        let total_secs = nanos / NANOS_PER_SECOND; // truncates towards zero
        let remaining_nanos = nanos % NANOS_PER_SECOND; // same sign as nanos

        let hours = total_secs / 3600;
        let rem_after_hours = total_secs % 3600;
        let minutes = rem_after_hours / 60;
        let seconds = rem_after_hours % 60;

        if hours != 0 || minutes != 0 || seconds != 0 || remaining_nanos != 0 {
            result.push('T');

            if hours != 0 {
                result.push_str(&format!("{}H", hours));
            }
            if minutes != 0 {
                result.push_str(&format!("{}M", minutes));
            }
            if seconds != 0 || remaining_nanos != 0 {
                if remaining_nanos != 0 {
                    // Combine seconds + remaining nanos into fractional seconds.
                    // Both have the same sign (truncating division preserves sign).
                    let secs_with_nanos = seconds as f64 + (remaining_nanos as f64 / 1e9);
                    let formatted = format!("{:.9}", secs_with_nanos);
                    let trimmed = formatted.trim_end_matches('0').trim_end_matches('.');
                    result.push_str(trimmed);
                    result.push('S');
                } else {
                    result.push_str(&format!("{}S", seconds));
                }
            }
        }

        // Handle case where duration is zero
        if result == "P" {
            result.push_str("T0S");
        }

        result
    }

    /// Get total as microseconds (for arithmetic operations).
    pub fn to_micros(&self) -> i64 {
        let month_days = self.months * 30; // Approximate
        let total_days = month_days + self.days;
        let day_micros = total_days * MICROS_PER_DAY;
        let nano_micros = self.nanos / 1000;
        day_micros + nano_micros
    }

    /// Component-wise addition of two durations.
    pub fn add(&self, other: &CypherDuration) -> CypherDuration {
        CypherDuration::new(
            self.months + other.months,
            self.days + other.days,
            self.nanos + other.nanos,
        )
    }

    /// Component-wise subtraction of two durations.
    pub fn sub(&self, other: &CypherDuration) -> CypherDuration {
        CypherDuration::new(
            self.months - other.months,
            self.days - other.days,
            self.nanos - other.nanos,
        )
    }

    /// Negate all components.
    pub fn negate(&self) -> CypherDuration {
        CypherDuration::new(-self.months, -self.days, -self.nanos)
    }

    /// Multiply duration by a factor with fractional cascading.
    pub fn multiply(&self, factor: f64) -> CypherDuration {
        let months_f = self.months as f64 * factor;
        let whole_months = months_f.trunc() as i64;
        let frac_months = months_f.fract();

        // Cascade fractional months via average Gregorian month (2629746 seconds).
        let frac_month_seconds = frac_months * 2_629_746.0;
        let extra_days_from_months = (frac_month_seconds / SECONDS_PER_DAY as f64).trunc();
        let remaining_secs_from_months =
            frac_month_seconds - extra_days_from_months * SECONDS_PER_DAY as f64;

        let days_f = self.days as f64 * factor + extra_days_from_months;
        let whole_days = days_f.trunc() as i64;
        let frac_days = days_f.fract();

        let nanos_f = self.nanos as f64 * factor
            + remaining_secs_from_months * NANOS_PER_SECOND as f64
            + frac_days * NANOS_PER_DAY as f64;

        CypherDuration::new(whole_months, whole_days, nanos_f.trunc() as i64)
    }

    /// Divide duration by a divisor with fractional cascading.
    pub fn divide(&self, divisor: f64) -> CypherDuration {
        if divisor == 0.0 {
            // Return zero duration for division by zero (matches Cypher behavior)
            return CypherDuration::new(0, 0, 0);
        }
        self.multiply(1.0 / divisor)
    }
}

// ============================================================================
// Calendar-Aware Duration Arithmetic
// ============================================================================

/// Add months to a date with day-of-month clamping.
///
/// If the resulting month has fewer days than the source day,
/// the day is clamped to the last day of the month.
/// For example, `Jan 31 + 1 month = Feb 28` (or Feb 29 in leap years).
pub fn add_months_to_date(date: NaiveDate, months: i64) -> NaiveDate {
    if months == 0 {
        return date;
    }

    let total_months = date.year() as i64 * 12 + (date.month() as i64 - 1) + months;
    let new_year = total_months.div_euclid(12) as i32;
    let new_month = (total_months.rem_euclid(12) + 1) as u32;

    // Clamp day to valid range for the new month
    let max_day = days_in_month(new_year, new_month);
    let new_day = date.day().min(max_day);

    NaiveDate::from_ymd_opt(new_year, new_month, new_day)
        .unwrap_or_else(|| NaiveDate::from_ymd_opt(new_year, new_month, 1).unwrap())
}

/// Get number of days in a given month.
fn days_in_month(year: i32, month: u32) -> u32 {
    match month {
        1 | 3 | 5 | 7 | 8 | 10 | 12 => 31,
        4 | 6 | 9 | 11 => 30,
        2 => {
            if year % 4 == 0 && (year % 100 != 0 || year % 400 == 0) {
                29
            } else {
                28
            }
        }
        _ => 30,
    }
}

/// Add a CypherDuration to a date string, returning the result date string.
///
/// Algorithm: add months (clamping) -> add days -> add nanos (overflow into extra days).
pub fn add_cypher_duration_to_date(date_str: &str, dur: &CypherDuration) -> Result<String> {
    let date = NaiveDate::parse_from_str(date_str, "%Y-%m-%d")?;

    // Step 1: Add months with clamping
    let after_months = add_months_to_date(date, dur.months);

    // Step 2: Add days
    let after_days = after_months + Duration::days(dur.days);

    // Step 3: Add nanos (overflow into extra full days; sub-day remainder is discarded for dates)
    // Use truncating division (/) so negative sub-day nanos don't subtract an extra day.
    let extra_days = dur.nanos / NANOS_PER_DAY;
    let result = after_days + Duration::days(extra_days);

    Ok(result.format("%Y-%m-%d").to_string())
}

/// Add a CypherDuration to a local time string, returning the result time string.
///
/// Time wraps modulo 24 hours. No date component is affected.
pub fn add_cypher_duration_to_localtime(time_str: &str, dur: &CypherDuration) -> Result<String> {
    let time = parse_time_string(time_str)?;
    let total_nanos = time_to_nanos(&time) + dur.nanos;
    // Wrap modulo 24h
    let wrapped = total_nanos.rem_euclid(NANOS_PER_DAY);
    let result = nanos_to_time(wrapped);
    Ok(format_time_with_nanos(&result))
}

/// Add a CypherDuration to a time-with-timezone string, returning the result time string.
///
/// Time wraps modulo 24 hours, preserving the original timezone offset.
pub fn add_cypher_duration_to_time(time_str: &str, dur: &CypherDuration) -> Result<String> {
    let (_, time, tz_info) = parse_datetime_with_tz(time_str)?;
    let total_nanos = time_to_nanos(&time) + dur.nanos;
    let wrapped = total_nanos.rem_euclid(NANOS_PER_DAY);
    let result_time = nanos_to_time(wrapped);

    let time_part = format_time_with_nanos(&result_time);
    if let Some(ref tz) = tz_info {
        let today = NaiveDate::from_ymd_opt(2000, 1, 1).unwrap();
        let ndt = NaiveDateTime::new(today, result_time);
        let offset = tz.offset_for_local(&ndt)?;
        let offset_str = format_timezone_offset(offset.local_minus_utc());
        Ok(format!("{}{}", time_part, offset_str))
    } else {
        Ok(time_part)
    }
}

/// Add a CypherDuration to a local datetime string, returning the result string.
pub fn add_cypher_duration_to_localdatetime(dt_str: &str, dur: &CypherDuration) -> Result<String> {
    let ndt = NaiveDateTime::parse_from_str(dt_str, "%Y-%m-%dT%H:%M:%S")
        .or_else(|_| NaiveDateTime::parse_from_str(dt_str, "%Y-%m-%dT%H:%M:%S%.f"))
        .or_else(|_| NaiveDateTime::parse_from_str(dt_str, "%Y-%m-%dT%H:%M"))
        .map_err(|_| anyhow!("Invalid localdatetime: {}", dt_str))?;

    // Step 1: Add months with clamping
    let after_months = add_months_to_date(ndt.date(), dur.months);
    // Step 2: Add days
    let after_days = after_months + Duration::days(dur.days);
    // Step 3: Add nanos to time
    let result_ndt = NaiveDateTime::new(after_days, ndt.time()) + Duration::nanoseconds(dur.nanos);

    Ok(format_naive_datetime(&result_ndt))
}

/// Add a CypherDuration to a datetime-with-timezone string, returning the result string.
pub fn add_cypher_duration_to_datetime(dt_str: &str, dur: &CypherDuration) -> Result<String> {
    let (date, time, tz_info) = parse_datetime_with_tz(dt_str)?;

    // Step 1: Add months with clamping
    let after_months = add_months_to_date(date, dur.months);
    // Step 2: Add days
    let after_days = after_months + Duration::days(dur.days);
    // Step 3: Add nanos to the datetime
    let ndt = NaiveDateTime::new(after_days, time) + Duration::nanoseconds(dur.nanos);

    if let Some(ref tz) = tz_info {
        let offset = tz.offset_for_local(&ndt)?;
        let dt = offset
            .from_local_datetime(&ndt)
            .single()
            .ok_or_else(|| anyhow!("Ambiguous local time after duration addition"))?;
        Ok(format_datetime_with_offset_and_tz(&dt, tz.name()))
    } else {
        let dt = DateTime::<Utc>::from_naive_utc_and_offset(ndt, Utc);
        Ok(format_datetime_with_nanos(&dt))
    }
}

/// Convert NaiveTime to total nanoseconds since midnight.
fn time_to_nanos(t: &NaiveTime) -> i64 {
    t.hour() as i64 * 3_600 * NANOS_PER_SECOND
        + t.minute() as i64 * 60 * NANOS_PER_SECOND
        + t.second() as i64 * NANOS_PER_SECOND
        + t.nanosecond() as i64
}

/// Convert total nanoseconds since midnight to NaiveTime.
fn nanos_to_time(nanos: i64) -> NaiveTime {
    let total_secs = nanos / NANOS_PER_SECOND;
    let remaining_nanos = (nanos % NANOS_PER_SECOND) as u32;
    let h = (total_secs / 3600) as u32;
    let m = ((total_secs % 3600) / 60) as u32;
    let s = (total_secs % 60) as u32;
    NaiveTime::from_hms_nano_opt(h, m, s, remaining_nanos)
        .unwrap_or_else(|| NaiveTime::from_hms_opt(0, 0, 0).unwrap())
}

// ============================================================================
// Duration Constructor
// ============================================================================

fn eval_duration(args: &[Value]) -> Result<Value> {
    if args.len() != 1 {
        return Err(anyhow!("duration() requires 1 argument"));
    }

    match &args[0] {
        Value::String(s) => {
            let duration = parse_duration_to_cypher(s)?;
            Ok(Value::Temporal(TemporalValue::Duration {
                months: duration.months,
                days: duration.days,
                nanos: duration.nanos,
            }))
        }
        Value::Temporal(TemporalValue::Duration { .. }) => Ok(args[0].clone()),
        Value::Map(map) => eval_duration_from_map(map),
        Value::Int(_) | Value::Float(_) => {
            if let Some(micros) = args[0].as_i64() {
                let duration = CypherDuration::from_micros(micros);
                Ok(Value::Temporal(TemporalValue::Duration {
                    months: duration.months,
                    days: duration.days,
                    nanos: duration.nanos,
                }))
            } else {
                Ok(args[0].clone())
            }
        }
        Value::Null => Ok(Value::Null),
        _ => Err(anyhow!("duration() expects a string, map, or number")),
    }
}

/// Build duration from a map with fractional cascading.
///
/// Fractional parts cascade to the next smaller unit:
/// - `months: 5.5` -> 5 months + 15 days (0.5 * 30)
/// - `days: 14.5` -> 14 days + 12 hours (0.5 * 24h in nanos)
fn eval_duration_from_map(map: &HashMap<String, Value>) -> Result<Value> {
    let mut months_f: f64 = 0.0;
    let mut days_f: f64 = 0.0;
    let mut nanos_f: f64 = 0.0;

    // Calendar components with fractional cascading
    if let Some(years) = map.get("years").and_then(get_numeric_value) {
        months_f += years * 12.0;
    }
    if let Some(m) = map.get("months").and_then(get_numeric_value) {
        months_f += m;
    }

    // Cascade fractional months to days + remaining nanos.
    // Neo4j uses average Gregorian month: 2629746 seconds (= 365.2425 * 86400 / 12).
    let whole_months = months_f.trunc() as i64;
    let frac_months = months_f.fract();
    let frac_month_seconds = frac_months * 2_629_746.0;
    let extra_days_from_months = (frac_month_seconds / SECONDS_PER_DAY as f64).trunc();
    let remaining_secs_from_months =
        frac_month_seconds - extra_days_from_months * SECONDS_PER_DAY as f64;
    days_f += extra_days_from_months;
    nanos_f += remaining_secs_from_months * NANOS_PER_SECOND as f64;

    if let Some(weeks) = map.get("weeks").and_then(get_numeric_value) {
        days_f += weeks * 7.0;
    }
    if let Some(d) = map.get("days").and_then(get_numeric_value) {
        days_f += d;
    }

    // Cascade fractional days to nanos (1 day = 24h in nanos)
    let whole_days = days_f.trunc() as i64;
    let frac_days = days_f.fract();
    nanos_f += frac_days * NANOS_PER_DAY as f64;

    // Time components (stored as nanoseconds)
    if let Some(hours) = map.get("hours").and_then(get_numeric_value) {
        nanos_f += hours * 3600.0 * NANOS_PER_SECOND as f64;
    }
    if let Some(minutes) = map.get("minutes").and_then(get_numeric_value) {
        nanos_f += minutes * 60.0 * NANOS_PER_SECOND as f64;
    }
    if let Some(seconds) = map.get("seconds").and_then(get_numeric_value) {
        nanos_f += seconds * NANOS_PER_SECOND as f64;
    }
    if let Some(millis) = map.get("milliseconds").and_then(get_numeric_value) {
        nanos_f += millis * 1_000_000.0;
    }
    if let Some(micros) = map.get("microseconds").and_then(get_numeric_value) {
        nanos_f += micros * 1_000.0;
    }
    if let Some(n) = map.get("nanoseconds").and_then(get_numeric_value) {
        nanos_f += n;
    }

    let duration = CypherDuration::new(whole_months, whole_days, nanos_f.trunc() as i64);
    Ok(Value::Temporal(TemporalValue::Duration {
        months: duration.months,
        days: duration.days,
        nanos: duration.nanos,
    }))
}

/// Extract numeric value from JSON, supporting both integers and floats.
fn get_numeric_value(v: &Value) -> Option<f64> {
    v.as_f64().or_else(|| v.as_i64().map(|i| i as f64))
}

/// Parse ISO 8601 duration format (e.g., "P1DT2H30M15S").
fn parse_iso8601_duration(s: &str) -> Result<i64> {
    let s = &s[1..]; // Skip 'P'
    let mut total_micros: i64 = 0;
    let mut in_time_part = false;
    let mut num_buf = String::new();

    for c in s.chars() {
        if c == 'T' || c == 't' {
            in_time_part = true;
            continue;
        }

        if c.is_ascii_digit() || c == '.' || c == '-' {
            num_buf.push(c);
        } else {
            if num_buf.is_empty() {
                continue;
            }
            let num: f64 = num_buf
                .parse()
                .map_err(|_| anyhow!("Invalid duration number"))?;
            num_buf.clear();

            let micros = match c {
                'Y' | 'y' => (num * 365.0 * MICROS_PER_DAY as f64) as i64,
                'M' if !in_time_part => (num * 30.0 * MICROS_PER_DAY as f64) as i64, // Months
                'W' | 'w' => (num * 7.0 * MICROS_PER_DAY as f64) as i64,
                'D' | 'd' => (num * MICROS_PER_DAY as f64) as i64,
                'H' | 'h' => (num * MICROS_PER_HOUR as f64) as i64,
                'M' | 'm' if in_time_part => (num * MICROS_PER_MINUTE as f64) as i64, // Minutes
                'S' | 's' => (num * MICROS_PER_SECOND as f64) as i64,
                _ => return Err(anyhow!("Invalid ISO 8601 duration designator: {}", c)),
            };
            total_micros += micros;
        }
    }

    Ok(total_micros)
}

/// Parse simple duration format (e.g., "1d2h30m15s", "90s", "1h30m").
fn parse_simple_duration(s: &str) -> Result<i64> {
    let mut total_micros: i64 = 0;
    let mut num_buf = String::new();

    for c in s.chars() {
        if c.is_ascii_digit() || c == '.' || c == '-' {
            num_buf.push(c);
        } else if c.is_ascii_alphabetic() {
            if num_buf.is_empty() {
                return Err(anyhow!("Invalid duration format"));
            }
            let num: f64 = num_buf
                .parse()
                .map_err(|_| anyhow!("Invalid duration number"))?;
            num_buf.clear();

            let micros = match c {
                'w' => (num * 7.0 * MICROS_PER_DAY as f64) as i64,
                'd' => (num * MICROS_PER_DAY as f64) as i64,
                'h' => (num * MICROS_PER_HOUR as f64) as i64,
                'm' => (num * MICROS_PER_MINUTE as f64) as i64,
                's' => (num * MICROS_PER_SECOND as f64) as i64,
                _ => return Err(anyhow!("Invalid duration unit: {}", c)),
            };
            total_micros += micros;
        }
    }

    // Handle case where string is just a number (assume seconds)
    if !num_buf.is_empty() {
        let num: f64 = num_buf
            .parse()
            .map_err(|_| anyhow!("Invalid duration number"))?;
        total_micros += (num * MICROS_PER_SECOND as f64) as i64;
    }

    Ok(total_micros)
}

// ============================================================================
// Epoch Functions
// ============================================================================

fn eval_datetime_fromepoch(args: &[Value]) -> Result<Value> {
    let seconds = args
        .first()
        .and_then(|v| v.as_i64())
        .ok_or_else(|| anyhow!("datetime.fromepoch requires seconds argument"))?;
    let nanos = args.get(1).and_then(|v| v.as_i64()).unwrap_or(0) as u32;

    let dt = DateTime::from_timestamp(seconds, nanos)
        .ok_or_else(|| anyhow!("Invalid epoch timestamp: {}", seconds))?;
    let epoch_nanos = dt.timestamp_nanos_opt().unwrap_or(0);
    Ok(Value::Temporal(TemporalValue::DateTime {
        nanos_since_epoch: epoch_nanos,
        offset_seconds: 0,
        timezone_name: None,
    }))
}

fn eval_datetime_fromepochmillis(args: &[Value]) -> Result<Value> {
    let millis = args
        .first()
        .and_then(|v| v.as_i64())
        .ok_or_else(|| anyhow!("datetime.fromepochmillis requires milliseconds argument"))?;

    let dt = DateTime::from_timestamp_millis(millis)
        .ok_or_else(|| anyhow!("Invalid epoch millis: {}", millis))?;
    let epoch_nanos = dt.timestamp_nanos_opt().unwrap_or(0);
    Ok(Value::Temporal(TemporalValue::DateTime {
        nanos_since_epoch: epoch_nanos,
        offset_seconds: 0,
        timezone_name: None,
    }))
}

// ============================================================================
// Truncate Functions
// ============================================================================

fn eval_truncate(type_name: &str, args: &[Value]) -> Result<Value> {
    if args.is_empty() {
        return Err(anyhow!(
            "{}.truncate requires at least a unit argument",
            type_name
        ));
    }

    let unit = args
        .first()
        .and_then(|v| v.as_str())
        .ok_or_else(|| anyhow!("truncate requires unit as first argument"))?;

    let temporal = args.get(1);
    let adjust_map = args.get(2).and_then(|v| v.as_object());

    match type_name {
        "date" => truncate_date(unit, temporal, adjust_map),
        "time" => truncate_time(unit, temporal, adjust_map, true),
        "localtime" => truncate_time(unit, temporal, adjust_map, false),
        "datetime" | "localdatetime" => truncate_datetime(unit, temporal, adjust_map, type_name),
        _ => Err(anyhow!("Unknown truncate type: {}", type_name)),
    }
}

fn truncate_date(
    unit: &str,
    temporal: Option<&Value>,
    adjust_map: Option<&HashMap<String, Value>>,
) -> Result<Value> {
    let date = match temporal {
        Some(Value::Temporal(_)) => temporal_or_string_to_date(temporal.unwrap())?,
        Some(Value::String(s)) => parse_date_string(s)?,
        Some(Value::Null) | None => Utc::now().date_naive(),
        _ => return Err(anyhow!("truncate expects a date string")),
    };

    let truncated = truncate_date_to_unit(date, unit)?;

    if let Some(map) = adjust_map {
        apply_date_adjustments(truncated, map)
    } else {
        Ok(Value::Temporal(TemporalValue::Date {
            days_since_epoch: date_to_days_since_epoch(&truncated),
        }))
    }
}

fn truncate_date_to_unit(date: NaiveDate, unit: &str) -> Result<NaiveDate> {
    let unit_lower = unit.to_lowercase();
    match unit_lower.as_str() {
        "millennium" => {
            // 2017 -> 2000, 1984 -> 1000, 999 -> 0
            let millennium_year = (date.year() / 1000) * 1000;
            NaiveDate::from_ymd_opt(millennium_year, 1, 1)
                .ok_or_else(|| anyhow!("Invalid millennium truncation"))
        }
        "century" => {
            // 1984 -> 1900, 2017 -> 2000
            let century_year = (date.year() / 100) * 100;
            NaiveDate::from_ymd_opt(century_year, 1, 1)
                .ok_or_else(|| anyhow!("Invalid century truncation"))
        }
        "decade" => {
            let decade_year = (date.year() / 10) * 10;
            NaiveDate::from_ymd_opt(decade_year, 1, 1)
                .ok_or_else(|| anyhow!("Invalid decade truncation"))
        }
        "year" => NaiveDate::from_ymd_opt(date.year(), 1, 1)
            .ok_or_else(|| anyhow!("Invalid year truncation")),
        "weekyear" => {
            // Truncate to first day of ISO week year
            let iso_week = date.iso_week();
            let week_year = iso_week.year();
            let jan4 =
                NaiveDate::from_ymd_opt(week_year, 1, 4).ok_or_else(|| anyhow!("Invalid date"))?;
            let iso_week_day = jan4.weekday().num_days_from_monday();
            Ok(jan4 - Duration::days(iso_week_day as i64))
        }
        "quarter" => {
            let quarter = (date.month() - 1) / 3;
            let first_month = quarter * 3 + 1;
            NaiveDate::from_ymd_opt(date.year(), first_month, 1)
                .ok_or_else(|| anyhow!("Invalid quarter truncation"))
        }
        "month" => NaiveDate::from_ymd_opt(date.year(), date.month(), 1)
            .ok_or_else(|| anyhow!("Invalid month truncation")),
        "week" => {
            // Truncate to Monday of current week
            let weekday = date.weekday().num_days_from_monday();
            Ok(date - Duration::days(weekday as i64))
        }
        "day" => Ok(date),
        _ => Err(anyhow!("Unknown truncation unit for date: {}", unit)),
    }
}

fn apply_date_adjustments(date: NaiveDate, map: &HashMap<String, Value>) -> Result<Value> {
    let mut result = date;

    // Handle dayOfWeek adjustment (moves to different day in the same week)
    if let Some(dow) = map.get("dayOfWeek").and_then(|v| v.as_i64()) {
        // dayOfWeek: 1=Monday, 7=Sunday
        // Calculate the offset from Monday
        let current_dow = result.weekday().num_days_from_monday() as i64 + 1;
        let diff = dow - current_dow;
        result += Duration::days(diff);
    }

    if let Some(month) = map.get("month").and_then(|v| v.as_i64()) {
        result = NaiveDate::from_ymd_opt(result.year(), month as u32, result.day())
            .ok_or_else(|| anyhow!("Invalid month adjustment"))?;
    }
    if let Some(day) = map.get("day").and_then(|v| v.as_i64()) {
        result = NaiveDate::from_ymd_opt(result.year(), result.month(), day as u32)
            .ok_or_else(|| anyhow!("Invalid day adjustment"))?;
    }

    Ok(Value::Temporal(TemporalValue::Date {
        days_since_epoch: date_to_days_since_epoch(&result),
    }))
}

fn truncate_time(
    unit: &str,
    temporal: Option<&Value>,
    adjust_map: Option<&HashMap<String, Value>>,
    with_timezone: bool,
) -> Result<Value> {
    let (date, time, tz_info) = match temporal {
        Some(Value::Temporal(tv)) => {
            let t = tv
                .to_time()
                .unwrap_or_else(|| NaiveTime::from_hms_opt(0, 0, 0).unwrap());
            let offset = match tv {
                TemporalValue::Time { offset_seconds, .. }
                | TemporalValue::DateTime { offset_seconds, .. } => Some(
                    TimezoneInfo::FixedOffset(FixedOffset::east_opt(*offset_seconds).unwrap()),
                ),
                _ => None,
            };
            (Utc::now().date_naive(), t, offset)
        }
        Some(Value::String(s)) => {
            // Try to parse as datetime/time with timezone first
            if let Ok((date, time, tz)) = parse_datetime_with_tz(s) {
                (date, time, tz)
            } else if let Ok(t) = parse_time_string(s) {
                // Use today for time-only parsing
                (Utc::now().date_naive(), t, None)
            } else {
                return Err(anyhow!("truncate expects a time string"));
            }
        }
        Some(Value::Null) | None => {
            let now = Utc::now();
            (now.date_naive(), now.time(), None)
        }
        _ => return Err(anyhow!("truncate expects a time string")),
    };

    // Check if adjustment map specifies a timezone override
    let effective_tz = if let Some(map) = adjust_map {
        if let Some(tz_str) = map.get("timezone").and_then(|v| v.as_str()) {
            Some(parse_timezone(tz_str)?)
        } else {
            tz_info
        }
    } else {
        tz_info
    };

    let truncated = truncate_time_to_unit(time, unit)?;

    let final_time = if let Some(map) = adjust_map {
        apply_time_adjustments(truncated, map)?
    } else {
        truncated
    };

    // Return typed temporal value
    let nanos = time_to_nanos(&final_time);
    if with_timezone {
        let offset = if let Some(ref tz) = effective_tz {
            tz.offset_seconds_with_date(&date)
        } else {
            0
        };
        Ok(Value::Temporal(TemporalValue::Time {
            nanos_since_midnight: nanos,
            offset_seconds: offset,
        }))
    } else {
        Ok(Value::Temporal(TemporalValue::LocalTime {
            nanos_since_midnight: nanos,
        }))
    }
}

fn truncate_time_to_unit(time: NaiveTime, unit: &str) -> Result<NaiveTime> {
    let unit_lower = unit.to_lowercase();
    match unit_lower.as_str() {
        "day" => NaiveTime::from_hms_opt(0, 0, 0).ok_or_else(|| anyhow!("Invalid truncation")),
        "hour" => {
            NaiveTime::from_hms_opt(time.hour(), 0, 0).ok_or_else(|| anyhow!("Invalid truncation"))
        }
        "minute" => NaiveTime::from_hms_opt(time.hour(), time.minute(), 0)
            .ok_or_else(|| anyhow!("Invalid truncation")),
        "second" => NaiveTime::from_hms_opt(time.hour(), time.minute(), time.second())
            .ok_or_else(|| anyhow!("Invalid truncation")),
        "millisecond" => {
            let millis = time.nanosecond() / 1_000_000;
            NaiveTime::from_hms_nano_opt(
                time.hour(),
                time.minute(),
                time.second(),
                millis * 1_000_000,
            )
            .ok_or_else(|| anyhow!("Invalid truncation"))
        }
        "microsecond" => {
            let micros = time.nanosecond() / 1_000;
            NaiveTime::from_hms_nano_opt(time.hour(), time.minute(), time.second(), micros * 1_000)
                .ok_or_else(|| anyhow!("Invalid truncation"))
        }
        _ => Err(anyhow!("Unknown truncation unit for time: {}", unit)),
    }
}

/// Apply time adjustments from a map and return the adjusted NaiveTime.
fn apply_time_adjustments(time: NaiveTime, map: &HashMap<String, Value>) -> Result<NaiveTime> {
    let hour = map
        .get("hour")
        .and_then(|v| v.as_i64())
        .unwrap_or(time.hour() as i64) as u32;
    let minute = map
        .get("minute")
        .and_then(|v| v.as_i64())
        .unwrap_or(time.minute() as i64) as u32;
    let second = map
        .get("second")
        .and_then(|v| v.as_i64())
        .unwrap_or(time.second() as i64) as u32;
    let nanos = build_nanoseconds_with_base(map, time.nanosecond());

    NaiveTime::from_hms_nano_opt(hour, minute, second, nanos)
        .ok_or_else(|| anyhow!("Invalid time adjustment"))
}

fn truncate_datetime(
    unit: &str,
    temporal: Option<&Value>,
    adjust_map: Option<&HashMap<String, Value>>,
    type_name: &str,
) -> Result<Value> {
    let (date, time, tz_info) = match temporal {
        Some(Value::Temporal(_)) => temporal_or_string_to_components(temporal.unwrap())?,
        Some(Value::String(s)) => {
            // Use the new parser that preserves timezone info
            parse_datetime_with_tz(s)?
        }
        Some(Value::Null) | None => {
            let now = Utc::now();
            (
                now.date_naive(),
                now.time(),
                Some(TimezoneInfo::FixedOffset(FixedOffset::east_opt(0).unwrap())),
            )
        }
        _ => return Err(anyhow!("truncate expects a datetime string")),
    };

    // Check if adjustment map specifies a timezone
    let effective_tz = if let Some(map) = adjust_map {
        if let Some(tz_str) = map.get("timezone").and_then(|v| v.as_str()) {
            Some(parse_timezone(tz_str)?)
        } else {
            tz_info
        }
    } else {
        tz_info
    };

    // Truncate based on unit
    let (truncated_date, truncated_time) = truncate_datetime_to_unit(date, time, unit)?;

    if let Some(map) = adjust_map {
        apply_datetime_adjustments(
            truncated_date,
            truncated_time,
            map,
            type_name,
            effective_tz.as_ref(),
        )
    } else {
        let ndt = NaiveDateTime::new(truncated_date, truncated_time);
        if type_name == "localdatetime" {
            Ok(localdatetime_value_from_naive(&ndt))
        } else if let Some(ref tz) = effective_tz {
            let offset = tz.offset_for_local(&ndt)?;
            let offset_secs = offset.local_minus_utc();
            Ok(datetime_value_from_local_and_offset(
                &ndt,
                offset_secs,
                tz.name().map(|s| s.to_string()),
            ))
        } else {
            Ok(datetime_value_from_local_and_offset(&ndt, 0, None))
        }
    }
}

fn truncate_datetime_to_unit(
    date: NaiveDate,
    time: NaiveTime,
    unit: &str,
) -> Result<(NaiveDate, NaiveTime)> {
    let unit_lower = unit.to_lowercase();
    let midnight =
        NaiveTime::from_hms_opt(0, 0, 0).ok_or_else(|| anyhow!("Failed to create midnight"))?;

    match unit_lower.as_str() {
        // Date-level truncations reset time to midnight
        "millennium" | "century" | "decade" | "year" | "weekyear" | "quarter" | "month"
        | "week" | "day" => {
            let truncated_date = truncate_date_to_unit(date, unit)?;
            Ok((truncated_date, midnight))
        }
        // Time-level truncations keep the date
        "hour" | "minute" | "second" | "millisecond" | "microsecond" => {
            let truncated_time = truncate_time_to_unit(time, unit)?;
            Ok((date, truncated_time))
        }
        _ => Err(anyhow!("Unknown truncation unit: {}", unit)),
    }
}

fn apply_datetime_adjustments(
    date: NaiveDate,
    time: NaiveTime,
    map: &HashMap<String, Value>,
    type_name: &str,
    tz_info: Option<&TimezoneInfo>,
) -> Result<Value> {
    // Apply date adjustments
    let year = map
        .get("year")
        .and_then(|v| v.as_i64())
        .unwrap_or(date.year() as i64) as i32;
    let month = map
        .get("month")
        .and_then(|v| v.as_i64())
        .unwrap_or(date.month() as i64) as u32;
    let day = map
        .get("day")
        .and_then(|v| v.as_i64())
        .unwrap_or(date.day() as i64) as u32;

    // Apply time adjustments
    let hour = map
        .get("hour")
        .and_then(|v| v.as_i64())
        .unwrap_or(time.hour() as i64) as u32;
    let minute = map
        .get("minute")
        .and_then(|v| v.as_i64())
        .unwrap_or(time.minute() as i64) as u32;
    let second = map
        .get("second")
        .and_then(|v| v.as_i64())
        .unwrap_or(time.second() as i64) as u32;
    let nanos = build_nanoseconds_with_base(map, time.nanosecond());

    let mut adjusted_date = NaiveDate::from_ymd_opt(year, month, day)
        .ok_or_else(|| anyhow!("Invalid date in adjustment"))?;

    // Handle dayOfWeek adjustment (moves to different day in the same week)
    if let Some(dow) = map.get("dayOfWeek").and_then(|v| v.as_i64()) {
        let current_dow = adjusted_date.weekday().num_days_from_monday() as i64 + 1;
        let diff = dow - current_dow;
        adjusted_date += Duration::days(diff);
    }

    let adjusted_time = NaiveTime::from_hms_nano_opt(hour, minute, second, nanos)
        .ok_or_else(|| anyhow!("Invalid time in adjustment"))?;

    let ndt = NaiveDateTime::new(adjusted_date, adjusted_time);

    if type_name == "localdatetime" {
        Ok(localdatetime_value_from_naive(&ndt))
    } else if let Some(tz) = tz_info {
        let offset = tz.offset_for_local(&ndt)?;
        let offset_secs = offset.local_minus_utc();
        Ok(datetime_value_from_local_and_offset(
            &ndt,
            offset_secs,
            tz.name().map(|s| s.to_string()),
        ))
    } else {
        Ok(datetime_value_from_local_and_offset(&ndt, 0, None))
    }
}

// ============================================================================
// Duration Between Functions
// ============================================================================

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct ExtendedDate {
    year: i64,
    month: u32,
    day: u32,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct ExtendedLocalDateTime {
    date: ExtendedDate,
    hour: u32,
    minute: u32,
    second: u32,
    nanosecond: u32,
}

fn is_leap_year_i64(year: i64) -> bool {
    year.rem_euclid(4) == 0 && (year.rem_euclid(100) != 0 || year.rem_euclid(400) == 0)
}

fn days_in_month_i64(year: i64, month: u32) -> Option<u32> {
    let days = match month {
        1 | 3 | 5 | 7 | 8 | 10 | 12 => 31,
        4 | 6 | 9 | 11 => 30,
        2 => {
            if is_leap_year_i64(year) {
                29
            } else {
                28
            }
        }
        _ => return None,
    };
    Some(days)
}

fn parse_extended_date_string(s: &str) -> Option<ExtendedDate> {
    let bytes = s.as_bytes();
    if bytes.is_empty() {
        return None;
    }

    let mut idx = 0usize;
    if matches!(bytes[0], b'+' | b'-') {
        idx += 1;
    }
    if idx >= bytes.len() || !bytes[idx].is_ascii_digit() {
        return None;
    }

    while idx < bytes.len() && bytes[idx].is_ascii_digit() {
        idx += 1;
    }
    if idx >= bytes.len() || bytes[idx] != b'-' {
        return None;
    }

    let year: i64 = s[..idx].parse().ok()?;
    let rest = &s[idx + 1..];
    let (month_str, day_str) = rest.split_once('-')?;
    if month_str.len() != 2 || day_str.len() != 2 {
        return None;
    }
    let month: u32 = month_str.parse().ok()?;
    let day: u32 = day_str.parse().ok()?;
    let max_day = days_in_month_i64(year, month)?;
    if day == 0 || day > max_day {
        return None;
    }
    Some(ExtendedDate { year, month, day })
}

fn parse_extended_localdatetime_string(s: &str) -> Option<ExtendedLocalDateTime> {
    let (date_part, time_part) = if let Some((d, t)) = s.split_once('T') {
        (d, Some(t))
    } else {
        (s, None)
    };

    let date = parse_extended_date_string(date_part)?;

    let Some(time_part) = time_part else {
        return Some(ExtendedLocalDateTime {
            date,
            hour: 0,
            minute: 0,
            second: 0,
            nanosecond: 0,
        });
    };

    if time_part.contains('+') || time_part.contains('Z') || time_part.contains('z') {
        return None;
    }
    let (hms_part, frac_part) = if let Some((hms, frac)) = time_part.split_once('.') {
        (hms, Some(frac))
    } else {
        (time_part, None)
    };
    let mut parts = hms_part.split(':');
    let hour: u32 = parts.next()?.parse().ok()?;
    let minute: u32 = parts.next()?.parse().ok()?;
    let second: u32 = parts.next().map(|v| v.parse().ok()).unwrap_or(Some(0))?;
    if parts.next().is_some() {
        return None;
    }
    if hour > 23 || minute > 59 || second > 59 {
        return None;
    }

    let nanosecond = if let Some(frac) = frac_part {
        if frac.is_empty() || !frac.bytes().all(|b| b.is_ascii_digit()) {
            return None;
        }
        let mut frac_buf = frac.to_string();
        if frac_buf.len() > 9 {
            frac_buf.truncate(9);
        }
        while frac_buf.len() < 9 {
            frac_buf.push('0');
        }
        frac_buf.parse().ok()?
    } else {
        0
    };

    Some(ExtendedLocalDateTime {
        date,
        hour,
        minute,
        second,
        nanosecond,
    })
}

fn days_from_civil(date: ExtendedDate) -> i128 {
    // Howard Hinnant's civil-from-days algorithm, adapted for wide i64 year range.
    let mut y = date.year;
    let m = date.month as i64;
    let d = date.day as i64;
    y -= if m <= 2 { 1 } else { 0 };
    let era = y.div_euclid(400);
    let yoe = y - era * 400;
    let mp = m + if m > 2 { -3 } else { 9 };
    let doy = (153 * mp + 2) / 5 + d - 1;
    let doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
    era as i128 * 146_097 + doe as i128 - 719_468
}

fn calendar_months_between_extended(start: &ExtendedDate, end: &ExtendedDate) -> i64 {
    let year_diff = end.year - start.year;
    let month_diff = end.month as i64 - start.month as i64;
    let total_months = year_diff * 12 + month_diff;

    if total_months > 0 && end.day < start.day {
        total_months - 1
    } else if total_months < 0 && end.day > start.day {
        total_months + 1
    } else {
        total_months
    }
}

fn add_months_to_extended_date(date: ExtendedDate, months: i64) -> ExtendedDate {
    if months == 0 {
        return date;
    }

    let total_months = date.year as i128 * 12 + (date.month as i128 - 1) + months as i128;
    let year = total_months.div_euclid(12) as i64;
    let month = (total_months.rem_euclid(12) + 1) as u32;
    let max_day = days_in_month_i64(year, month).unwrap_or(31);
    let day = date.day.min(max_day);

    ExtendedDate { year, month, day }
}

fn remaining_days_after_months_extended(
    start: &ExtendedDate,
    end: &ExtendedDate,
    months: i64,
) -> i64 {
    let after_months = add_months_to_extended_date(*start, months);
    (days_from_civil(*end) - days_from_civil(after_months)) as i64
}

fn try_extended_date_from_value(val: &Value) -> Option<ExtendedDate> {
    match val {
        Value::String(s) => parse_extended_date_string(s),
        _ => None,
    }
}

fn try_extended_localdatetime_from_value(val: &Value) -> Option<ExtendedLocalDateTime> {
    match val {
        Value::String(s) => parse_extended_localdatetime_string(s),
        _ => None,
    }
}

fn try_eval_duration_between_extended(args: &[Value]) -> Result<Option<Value>> {
    let Some(start) = try_extended_date_from_value(&args[0]) else {
        return Ok(None);
    };
    let Some(end) = try_extended_date_from_value(&args[1]) else {
        return Ok(None);
    };

    let months = calendar_months_between_extended(&start, &end);
    let remaining_days = remaining_days_after_months_extended(&start, &end, months);
    let dur = CypherDuration::new(months, remaining_days, 0);
    Ok(Some(Value::String(dur.to_iso8601())))
}

fn format_time_only_duration_nanos(total_nanos: i128) -> String {
    if total_nanos == 0 {
        return "PT0S".to_string();
    }
    let total_secs = total_nanos / NANOS_PER_SECOND as i128;
    let rem_nanos = total_nanos % NANOS_PER_SECOND as i128;

    let hours = total_secs / 3600;
    let rem_after_hours = total_secs % 3600;
    let minutes = rem_after_hours / 60;
    let seconds = rem_after_hours % 60;

    let mut out = String::from("PT");
    if hours != 0 {
        out.push_str(&format!("{hours}H"));
    }
    if minutes != 0 {
        out.push_str(&format!("{minutes}M"));
    }
    if seconds != 0 || rem_nanos != 0 {
        if rem_nanos == 0 {
            out.push_str(&format!("{seconds}S"));
        } else {
            let sign = if total_nanos < 0 && seconds == 0 {
                "-"
            } else {
                ""
            };
            let secs_abs = seconds.abs();
            let nanos_abs = rem_nanos.abs();
            let frac = format!("{nanos_abs:09}");
            let trimmed = frac.trim_end_matches('0');
            out.push_str(&format!("{sign}{secs_abs}.{trimmed}S"));
        }
    }
    if out == "PT" { "PT0S".to_string() } else { out }
}

fn try_eval_duration_in_seconds_extended(args: &[Value]) -> Result<Option<Value>> {
    let Some(start) = try_extended_localdatetime_from_value(&args[0]) else {
        return Ok(None);
    };
    let Some(end) = try_extended_localdatetime_from_value(&args[1]) else {
        return Ok(None);
    };

    let start_days = days_from_civil(start.date);
    let end_days = days_from_civil(end.date);
    let start_tod_nanos =
        (start.hour as i128 * 3600 + start.minute as i128 * 60 + start.second as i128)
            * NANOS_PER_SECOND as i128
            + start.nanosecond as i128;
    let end_tod_nanos = (end.hour as i128 * 3600 + end.minute as i128 * 60 + end.second as i128)
        * NANOS_PER_SECOND as i128
        + end.nanosecond as i128;
    let total_nanos =
        (end_days - start_days) * NANOS_PER_DAY as i128 + (end_tod_nanos - start_tod_nanos);

    if total_nanos >= i64::MIN as i128 && total_nanos <= i64::MAX as i128 {
        let dur = CypherDuration::new(0, 0, total_nanos as i64);
        Ok(Some(dur.to_temporal_value()))
    } else {
        Ok(Some(Value::String(format_time_only_duration_nanos(
            total_nanos,
        ))))
    }
}

/// Compute calendar months between two dates.
///
/// Returns the number of whole months from `start` to `end`.
/// Negative if `end` is before `start`.
fn calendar_months_between(start: &NaiveDate, end: &NaiveDate) -> i64 {
    let year_diff = end.year() as i64 - start.year() as i64;
    let month_diff = end.month() as i64 - start.month() as i64;
    let total_months = year_diff * 12 + month_diff;

    // Adjust if end day is before start day (incomplete month)
    if total_months > 0 && end.day() < start.day() {
        total_months - 1
    } else if total_months < 0 && end.day() > start.day() {
        total_months + 1
    } else {
        total_months
    }
}

/// Compute the remaining days after removing whole months.
fn remaining_days_after_months(start: &NaiveDate, end: &NaiveDate, months: i64) -> i64 {
    let after_months = add_months_to_date(*start, months);
    end.signed_duration_since(after_months).num_days()
}

fn eval_duration_between(args: &[Value]) -> Result<Value> {
    if args.len() < 2 {
        return Err(anyhow!("duration.between requires two temporal arguments"));
    }
    if args[0].is_null() || args[1].is_null() {
        return Ok(Value::Null);
    }

    let start_res = parse_temporal_value_typed(&args[0]);
    let end_res = parse_temporal_value_typed(&args[1]);
    let (start, end) = match (start_res, end_res) {
        (Ok(start), Ok(end)) => (start, end),
        (start_res, end_res) => {
            if let Some(value) = try_eval_duration_between_extended(args)? {
                return Ok(value);
            }
            return Err(start_res
                .err()
                .or_else(|| end_res.err())
                .unwrap_or_else(|| anyhow!("duration.between requires two temporal arguments")));
        }
    };

    let start_has_date = has_date_component(start.ttype);
    let end_has_date = has_date_component(end.ttype);
    let start_has_time = has_time_component(start.ttype);
    let end_has_time = has_time_component(end.ttype);

    // Both are date-only: return calendar months + remaining days, no time component.
    if start.ttype == TemporalType::Date && end.ttype == TemporalType::Date {
        let months = calendar_months_between(&start.local_date, &end.local_date);
        let remaining_days =
            remaining_days_after_months(&start.local_date, &end.local_date, months);
        let dur = CypherDuration::new(months, remaining_days, 0);
        return Ok(dur.to_temporal_value());
    }

    // Both have date and time: calendar months + remaining time as nanos (no days).
    // Only use UTC normalization when BOTH operands have timezone info.
    if start_has_date && end_has_date && start_has_time && end_has_time {
        let tz_aware = both_tz_aware(&start, &end);
        let (s_date, s_time, e_date, e_time) = if tz_aware {
            (
                start.utc_datetime.date(),
                start.utc_datetime.time(),
                end.utc_datetime.date(),
                end.utc_datetime.time(),
            )
        } else {
            (
                start.local_date,
                start.local_time,
                end.local_date,
                end.local_time,
            )
        };

        let months = calendar_months_between(&s_date, &e_date);
        let date_after_months = add_months_to_date(s_date, months);
        let start_dt = NaiveDateTime::new(date_after_months, s_time);
        let end_dt = NaiveDateTime::new(e_date, e_time);
        let remaining_nanos = end_dt
            .signed_duration_since(start_dt)
            .num_nanoseconds()
            .unwrap_or(0);

        let dur = CypherDuration::new(months, 0, remaining_nanos);
        return Ok(dur.to_temporal_value());
    }

    // One has date+time, other is date-only: months + days + remaining time.
    if start_has_date && end_has_date {
        let tz_aware = both_tz_aware(&start, &end);
        let (s_date, s_time, e_date, e_time) = if tz_aware {
            (
                start.utc_datetime.date(),
                start.utc_datetime.time(),
                end.utc_datetime.date(),
                end.utc_datetime.time(),
            )
        } else {
            (
                start.local_date,
                start.local_time,
                end.local_date,
                end.local_time,
            )
        };

        let months = calendar_months_between(&s_date, &e_date);
        let date_after_months = add_months_to_date(s_date, months);
        let start_dt = NaiveDateTime::new(date_after_months, s_time);
        let end_dt = NaiveDateTime::new(e_date, e_time);
        let remaining = end_dt.signed_duration_since(start_dt);
        let remaining_days = remaining.num_days();
        let remaining_nanos =
            remaining.num_nanoseconds().unwrap_or(0) - remaining_days * 86_400_000_000_000;

        let dur = CypherDuration::new(months, remaining_days, remaining_nanos);
        return Ok(dur.to_temporal_value());
    }

    // Cross-type: one has date, other is time-only, or both time-only.
    // Use UTC normalization only when BOTH operands have timezone info.
    let tz_aware = both_tz_aware(&start, &end);
    let start_time = if tz_aware {
        start.utc_datetime.time()
    } else {
        start.local_time
    };
    let end_time = if tz_aware {
        end.utc_datetime.time()
    } else {
        end.local_time
    };

    let start_nanos = time_to_nanos(&start_time);
    let end_nanos = time_to_nanos(&end_time);
    let nanos_diff = end_nanos - start_nanos;

    let dur = CypherDuration::new(0, 0, nanos_diff);
    Ok(dur.to_temporal_value())
}

/// Check if a temporal type has a date component.
fn has_date_component(ttype: TemporalType) -> bool {
    matches!(
        ttype,
        TemporalType::Date | TemporalType::LocalDateTime | TemporalType::DateTime
    )
}

/// Check if a temporal type has a time component.
fn has_time_component(ttype: TemporalType) -> bool {
    matches!(
        ttype,
        TemporalType::LocalTime
            | TemporalType::Time
            | TemporalType::LocalDateTime
            | TemporalType::DateTime
    )
}

fn eval_duration_in_months(args: &[Value]) -> Result<Value> {
    if args.len() < 2 {
        return Err(anyhow!("duration.inMonths requires two temporal arguments"));
    }
    if args[0].is_null() || args[1].is_null() {
        return Ok(Value::Null);
    }

    let start = parse_temporal_value_typed(&args[0])?;
    let end = parse_temporal_value_typed(&args[1])?;

    if has_date_component(start.ttype) && has_date_component(end.ttype) {
        // Only use UTC normalization when both operands have timezone info
        let tz_aware = both_tz_aware(&start, &end);
        let (s_date, s_time, e_date, e_time) = if tz_aware {
            (
                start.utc_datetime.date(),
                start.utc_datetime.time(),
                end.utc_datetime.date(),
                end.utc_datetime.time(),
            )
        } else {
            (
                start.local_date,
                start.local_time,
                end.local_date,
                end.local_time,
            )
        };
        let mut months = calendar_months_between(&s_date, &e_date);
        // Adjust months if the time component crosses the day boundary:
        // When both fall on the same day-of-month, time determines if we've
        // crossed the boundary. E.g., 2018-07-21T00:00 -> 2016-07-21T21:40
        // is only 23 months (not 24) because end time is later in the day.
        if s_date.day() == e_date.day() {
            if months > 0 && e_time < s_time {
                months -= 1;
            } else if months < 0 && e_time > s_time {
                months += 1;
            }
        }
        let dur = CypherDuration::new(months, 0, 0);
        Ok(dur.to_temporal_value())
    } else {
        Ok(Value::Temporal(TemporalValue::Duration {
            months: 0,
            days: 0,
            nanos: 0,
        }))
    }
}

fn eval_duration_in_days(args: &[Value]) -> Result<Value> {
    if args.len() < 2 {
        return Err(anyhow!("duration.inDays requires two temporal arguments"));
    }
    if args[0].is_null() || args[1].is_null() {
        return Ok(Value::Null);
    }

    let start = parse_temporal_value_typed(&args[0])?;
    let end = parse_temporal_value_typed(&args[1])?;

    if has_date_component(start.ttype) && has_date_component(end.ttype) {
        // Only use UTC normalization when both operands have timezone info.
        let tz_aware = both_tz_aware(&start, &end);
        let (s_dt, e_dt) = if tz_aware {
            (start.utc_datetime, end.utc_datetime)
        } else {
            (
                NaiveDateTime::new(start.local_date, start.local_time),
                NaiveDateTime::new(end.local_date, end.local_time),
            )
        };
        // Compute total duration, then express as whole days (truncating toward zero).
        let total_nanos = e_dt
            .signed_duration_since(s_dt)
            .num_nanoseconds()
            .ok_or_else(|| anyhow!("Duration overflow in inDays"))?;
        let days = total_nanos / 86_400_000_000_000;
        let dur = CypherDuration::new(0, days, 0);
        Ok(dur.to_temporal_value())
    } else {
        Ok(Value::Temporal(TemporalValue::Duration {
            months: 0,
            days: 0,
            nanos: 0,
        }))
    }
}

/// Normalize a local datetime to UTC using a named IANA timezone.
///
/// When one operand has a named timezone (DST-aware) and the other is local
/// (no timezone), the local value must be interpreted in that named timezone
/// to correctly account for DST transitions.
fn normalize_local_to_utc(ndt: NaiveDateTime, tz: Tz) -> Result<NaiveDateTime> {
    use chrono::TimeZone;
    match tz.from_local_datetime(&ndt) {
        chrono::LocalResult::Single(dt) => Ok(dt.naive_utc()),
        chrono::LocalResult::Ambiguous(earliest, _) => Ok(earliest.naive_utc()),
        chrono::LocalResult::None => {
            // In a DST gap, shift forward by 1 hour and retry.
            let shifted = ndt + chrono::Duration::hours(1);
            match tz.from_local_datetime(&shifted) {
                chrono::LocalResult::Single(dt) => Ok(dt.naive_utc()),
                chrono::LocalResult::Ambiguous(earliest, _) => Ok(earliest.naive_utc()),
                _ => Err(anyhow!("Cannot resolve local time in timezone")),
            }
        }
    }
}

fn eval_duration_in_seconds(args: &[Value]) -> Result<Value> {
    if args.len() < 2 {
        return Err(anyhow!(
            "duration.inSeconds requires two temporal arguments"
        ));
    }
    if args[0].is_null() || args[1].is_null() {
        return Ok(Value::Null);
    }

    let start_res = parse_temporal_value_typed(&args[0]);
    let end_res = parse_temporal_value_typed(&args[1]);
    let (start, end) = match (start_res, end_res) {
        (Ok(start), Ok(end)) => (start, end),
        (start_res, end_res) => {
            if let Some(value) = try_eval_duration_in_seconds_extended(args)? {
                return Ok(value);
            }
            return Err(start_res
                .err()
                .or_else(|| end_res.err())
                .unwrap_or_else(|| anyhow!("duration.inSeconds requires two temporal arguments")));
        }
    };

    let start_has_date = has_date_component(start.ttype);
    let end_has_date = has_date_component(end.ttype);

    // Determine the shared named timezone for DST-aware normalization.
    // When one operand has a named (DST-aware) timezone (e.g., Europe/Stockholm),
    // local operands are interpreted in that timezone for correct DST handling.
    let shared_named_tz = start.named_tz.or(end.named_tz);

    // Resolve a temporal operand to a NaiveDateTime for comparison.
    //
    // Strategy:
    // - If a shared named timezone exists (DST scenario), normalize everything
    //   to UTC: tz-aware operands use their pre-computed UTC, local operands
    //   are interpreted in the shared named timezone then converted to UTC.
    // - If both operands have timezone info (fixed offsets), normalize to UTC.
    // - Otherwise (mixed local + fixed-offset, or both local), use face values.
    let have_tz = both_tz_aware(&start, &end);

    let resolve =
        |pt: &ParsedTemporal, date_override: Option<NaiveDate>| -> Result<NaiveDateTime> {
            let local_date = date_override.unwrap_or(pt.local_date);
            let local_ndt = NaiveDateTime::new(local_date, pt.local_time);

            if let Some(tz) = shared_named_tz {
                // DST-aware mode: normalize everything to UTC.
                if pt.named_tz.is_some() && date_override.is_none() {
                    // This operand owns the named tz — already UTC-normalized.
                    Ok(pt.utc_datetime)
                } else {
                    // Local operand or date-overridden: interpret in the shared tz.
                    normalize_local_to_utc(local_ndt, tz)
                }
            } else if have_tz {
                // Both have fixed offsets: use UTC normalization.
                if date_override.is_some() {
                    let offset = pt.utc_offset_secs.unwrap_or(0);
                    Ok(local_ndt - chrono::Duration::seconds(offset as i64))
                } else {
                    Ok(pt.utc_datetime)
                }
            } else {
                // Mixed local + fixed-offset or both local: use face values.
                Ok(local_ndt)
            }
        };

    // Cross-type with time-only operand.
    if !start_has_date || !end_has_date {
        if shared_named_tz.is_some() {
            // DST mode: place time-only operand on the date-bearing operand's
            // local date within the shared timezone.
            let ref_date = if start_has_date {
                start.local_date
            } else if end_has_date {
                end.local_date
            } else {
                NaiveDate::from_ymd_opt(1970, 1, 1).unwrap()
            };
            let s_dt = resolve(&start, Some(ref_date))?;
            let e_dt = resolve(&end, Some(ref_date))?;
            let total_nanos = e_dt
                .signed_duration_since(s_dt)
                .num_nanoseconds()
                .ok_or_else(|| anyhow!("Duration overflow in inSeconds"))?;
            let dur = CypherDuration::new(0, 0, total_nanos);
            return Ok(dur.to_temporal_value());
        }

        // No named timezone: simple time difference.
        let s_time = if have_tz {
            start.utc_datetime.time()
        } else {
            start.local_time
        };
        let e_time = if have_tz {
            end.utc_datetime.time()
        } else {
            end.local_time
        };
        let s_nanos = time_to_nanos(&s_time);
        let e_nanos = time_to_nanos(&e_time);
        let dur = CypherDuration::new(0, 0, e_nanos - s_nanos);
        return Ok(dur.to_temporal_value());
    }

    // Both have date: use full datetime difference.
    let s_dt = resolve(&start, None)?;
    let e_dt = resolve(&end, None)?;
    let total_nanos = e_dt
        .signed_duration_since(s_dt)
        .num_nanoseconds()
        .ok_or_else(|| anyhow!("Duration overflow in inSeconds"))?;

    let dur = CypherDuration::new(0, 0, total_nanos);
    Ok(dur.to_temporal_value())
}

/// Parsed temporal value with local and UTC-normalized components.
struct ParsedTemporal {
    /// Local date component (as written, before any UTC normalization).
    local_date: NaiveDate,
    /// Local time component (as written, before any UTC normalization).
    local_time: NaiveTime,
    /// UTC-normalized datetime (for absolute difference computation).
    utc_datetime: NaiveDateTime,
    /// Detected temporal type.
    ttype: TemporalType,
    /// Timezone offset in seconds from UTC, if applicable.
    utc_offset_secs: Option<i32>,
    /// The named IANA timezone, if present (for DST-aware cross-type computation).
    named_tz: Option<Tz>,
}

/// Check whether both temporal operands carry timezone information.
fn both_tz_aware(a: &ParsedTemporal, b: &ParsedTemporal) -> bool {
    a.utc_offset_secs.is_some() && b.utc_offset_secs.is_some()
}

/// Parse a temporal value into local components, UTC-normalized datetime, and type.
fn parse_temporal_value_typed(val: &Value) -> Result<ParsedTemporal> {
    let midnight =
        NaiveTime::from_hms_opt(0, 0, 0).ok_or_else(|| anyhow!("Failed to create midnight"))?;
    let epoch_date = NaiveDate::from_ymd_opt(1970, 1, 1).unwrap();

    match val {
        Value::String(s) => {
            let ttype = classify_temporal(s)
                .ok_or_else(|| anyhow!("Cannot classify temporal value: {}", s))?;

            match ttype {
                TemporalType::DateTime => {
                    let (date, time, tz_info) = parse_datetime_with_tz(s)?;
                    let local_ndt = NaiveDateTime::new(date, time);
                    let iana_tz = tz_info.as_ref().and_then(|info| match info {
                        TimezoneInfo::Named(tz) => Some(*tz),
                        _ => None,
                    });
                    let offset_secs = if let Some(ref info) = tz_info {
                        info.offset_for_local(&local_ndt)?.local_minus_utc()
                    } else {
                        0
                    };
                    let utc_ndt = local_ndt - chrono::Duration::seconds(offset_secs as i64);
                    Ok(ParsedTemporal {
                        local_date: date,
                        local_time: time,
                        utc_datetime: utc_ndt,
                        ttype,
                        utc_offset_secs: Some(offset_secs),

                        named_tz: iana_tz,
                    })
                }
                TemporalType::LocalDateTime => {
                    let ndt = NaiveDateTime::parse_from_str(s, "%Y-%m-%dT%H:%M:%S")
                        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%dT%H:%M:%S%.f"))
                        .or_else(|_| NaiveDateTime::parse_from_str(s, "%Y-%m-%dT%H:%M"))
                        .map_err(|_| anyhow!("Cannot parse localdatetime: {}", s))?;
                    Ok(ParsedTemporal {
                        local_date: ndt.date(),
                        local_time: ndt.time(),
                        utc_datetime: ndt,
                        ttype,
                        utc_offset_secs: None,

                        named_tz: None,
                    })
                }
                TemporalType::Date => {
                    let d = NaiveDate::parse_from_str(s, "%Y-%m-%d")
                        .map_err(|_| anyhow!("Cannot parse date: {}", s))?;
                    let ndt = NaiveDateTime::new(d, midnight);
                    Ok(ParsedTemporal {
                        local_date: d,
                        local_time: midnight,
                        utc_datetime: ndt,
                        ttype,
                        utc_offset_secs: None,

                        named_tz: None,
                    })
                }
                TemporalType::Time => {
                    let (_, time, tz_info) = parse_datetime_with_tz(s)?;
                    let offset_secs = if let Some(ref info) = tz_info {
                        let dummy_ndt = NaiveDateTime::new(epoch_date, time);
                        info.offset_for_local(&dummy_ndt)?.local_minus_utc()
                    } else {
                        0
                    };
                    let local_ndt = NaiveDateTime::new(epoch_date, time);
                    let utc_ndt = local_ndt - chrono::Duration::seconds(offset_secs as i64);
                    Ok(ParsedTemporal {
                        local_date: epoch_date,
                        local_time: time,
                        utc_datetime: utc_ndt,
                        ttype,
                        utc_offset_secs: Some(offset_secs),

                        named_tz: None,
                    })
                }
                TemporalType::LocalTime => {
                    let time = parse_time_string(s)?;
                    let ndt = NaiveDateTime::new(epoch_date, time);
                    Ok(ParsedTemporal {
                        local_date: epoch_date,
                        local_time: time,
                        utc_datetime: ndt,
                        ttype,
                        utc_offset_secs: None,

                        named_tz: None,
                    })
                }
                TemporalType::Duration | TemporalType::Btic => {
                    Err(anyhow!("Cannot use {:?} as temporal argument", ttype))
                }
            }
        }
        Value::Temporal(tv) => {
            let ttype = tv.temporal_type();
            match tv {
                TemporalValue::Date { days_since_epoch } => {
                    let d = epoch_date + chrono::Duration::days(*days_since_epoch as i64);
                    let ndt = NaiveDateTime::new(d, midnight);
                    Ok(ParsedTemporal {
                        local_date: d,
                        local_time: midnight,
                        utc_datetime: ndt,
                        ttype,
                        utc_offset_secs: None,
                        named_tz: None,
                    })
                }
                TemporalValue::LocalTime {
                    nanos_since_midnight,
                } => {
                    let time = nanos_to_time(*nanos_since_midnight);
                    let ndt = NaiveDateTime::new(epoch_date, time);
                    Ok(ParsedTemporal {
                        local_date: epoch_date,
                        local_time: time,
                        utc_datetime: ndt,
                        ttype,
                        utc_offset_secs: None,
                        named_tz: None,
                    })
                }
                TemporalValue::Time {
                    nanos_since_midnight,
                    offset_seconds,
                } => {
                    let time = nanos_to_time(*nanos_since_midnight);
                    let local_ndt = NaiveDateTime::new(epoch_date, time);
                    let utc_ndt = local_ndt - chrono::Duration::seconds(*offset_seconds as i64);
                    Ok(ParsedTemporal {
                        local_date: epoch_date,
                        local_time: time,
                        utc_datetime: utc_ndt,
                        ttype,
                        utc_offset_secs: Some(*offset_seconds),
                        named_tz: None,
                    })
                }
                TemporalValue::LocalDateTime { nanos_since_epoch } => {
                    let ndt =
                        chrono::DateTime::from_timestamp_nanos(*nanos_since_epoch).naive_utc();
                    Ok(ParsedTemporal {
                        local_date: ndt.date(),
                        local_time: ndt.time(),
                        utc_datetime: ndt,
                        ttype,
                        utc_offset_secs: None,
                        named_tz: None,
                    })
                }
                TemporalValue::DateTime {
                    nanos_since_epoch,
                    offset_seconds,
                    timezone_name,
                } => {
                    // Compute local time from UTC + offset
                    let local_nanos = nanos_since_epoch + (*offset_seconds as i64) * 1_000_000_000;
                    let local_ndt = chrono::DateTime::from_timestamp_nanos(local_nanos).naive_utc();
                    let utc_ndt =
                        chrono::DateTime::from_timestamp_nanos(*nanos_since_epoch).naive_utc();
                    let iana_tz = timezone_name
                        .as_deref()
                        .and_then(|name| name.parse::<chrono_tz::Tz>().ok());
                    Ok(ParsedTemporal {
                        local_date: local_ndt.date(),
                        local_time: local_ndt.time(),
                        utc_datetime: utc_ndt,
                        ttype,
                        utc_offset_secs: Some(*offset_seconds),
                        named_tz: iana_tz,
                    })
                }
                TemporalValue::Duration { .. } | TemporalValue::Btic { .. } => Err(anyhow!(
                    "Cannot use {:?} as temporal argument",
                    tv.temporal_type()
                )),
            }
        }
        _ => Err(anyhow!("Expected temporal value, got: {:?}", val)),
    }
}

// ============================================================================
// Tests
// ============================================================================

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

    /// Helper to build a Value::Map from key-value pairs.
    fn map_val(pairs: Vec<(&str, Value)>) -> Value {
        Value::Map(pairs.into_iter().map(|(k, v)| (k.to_string(), v)).collect())
    }

    #[test]
    fn test_parse_datetime_utc_accepts_bracketed_timezone_suffix() {
        let dt = parse_datetime_utc("2020-01-01T00:00Z[UTC]").unwrap();
        assert_eq!(dt.to_rfc3339(), "2020-01-01T00:00:00+00:00");

        let dt = parse_datetime_utc("2020-01-01T01:00:00+01:00[Europe/Paris]").unwrap();
        assert_eq!(dt.to_rfc3339(), "2020-01-01T00:00:00+00:00");
    }

    #[test]
    fn test_date_from_map_calendar() {
        let result = eval_date(&[map_val(vec![
            ("year", Value::Int(1984)),
            ("month", Value::Int(10)),
            ("day", Value::Int(11)),
        ])])
        .unwrap();
        assert_eq!(result.to_string(), "1984-10-11");
    }

    #[test]
    fn test_date_from_map_defaults() {
        let result = eval_date(&[map_val(vec![("year", Value::Int(1984))])]).unwrap();
        assert_eq!(result.to_string(), "1984-01-01");
    }

    #[test]
    fn test_date_from_week() {
        // Week 10, Wednesday (day 3) of 1984
        let result = eval_date(&[map_val(vec![
            ("year", Value::Int(1984)),
            ("week", Value::Int(10)),
            ("dayOfWeek", Value::Int(3)),
        ])])
        .unwrap();
        assert!(result.to_string().starts_with("1984-03"));
    }

    #[test]
    fn test_date_from_ordinal() {
        // Day 202 of 1984 (leap year)
        let result = eval_date(&[map_val(vec![
            ("year", Value::Int(1984)),
            ("ordinalDay", Value::Int(202)),
        ])])
        .unwrap();
        assert_eq!(result.to_string(), "1984-07-20");
    }

    #[test]
    fn test_date_from_quarter() {
        // Q3, day 45 of 1984
        let result = eval_date(&[map_val(vec![
            ("year", Value::Int(1984)),
            ("quarter", Value::Int(3)),
            ("dayOfQuarter", Value::Int(45)),
        ])])
        .unwrap();
        assert_eq!(result.to_string(), "1984-08-14");
    }

    #[test]
    fn test_time_from_map() {
        let result = eval_time(&[map_val(vec![
            ("hour", Value::Int(12)),
            ("minute", Value::Int(31)),
            ("second", Value::Int(14)),
        ])])
        .unwrap();
        assert_eq!(result.to_string(), "12:31:14Z");
    }

    #[test]
    fn test_time_from_map_with_nanos() {
        let result = eval_time(&[map_val(vec![
            ("hour", Value::Int(12)),
            ("minute", Value::Int(31)),
            ("second", Value::Int(14)),
            ("millisecond", Value::Int(645)),
            ("microsecond", Value::Int(876)),
            ("nanosecond", Value::Int(123)),
        ])])
        .unwrap();
        // TemporalValue stores microsecond precision (6 digits), nanos are truncated
        assert!(result.to_string().starts_with("12:31:14.645876"));
    }

    #[test]
    fn test_datetime_from_map() {
        let result = eval_datetime(&[map_val(vec![
            ("year", Value::Int(1984)),
            ("month", Value::Int(10)),
            ("day", Value::Int(11)),
            ("hour", Value::Int(12)),
        ])])
        .unwrap();
        assert!(result.to_string().contains("1984-10-11T12:00"));
    }

    #[test]
    fn test_localdatetime_from_week() {
        // Week 1 of 1816 should be 1816-01-01 (Monday of that week)
        let result = eval_localdatetime(&[map_val(vec![
            ("year", Value::Int(1816)),
            ("week", Value::Int(1)),
        ])])
        .unwrap();
        assert_eq!(result.to_string(), "1816-01-01T00:00");

        // Week 52 of 1816
        let result = eval_localdatetime(&[map_val(vec![
            ("year", Value::Int(1816)),
            ("week", Value::Int(52)),
        ])])
        .unwrap();
        assert_eq!(result.to_string(), "1816-12-23T00:00");

        // Week 1 of 1817 (starts in 1816!)
        let result = eval_localdatetime(&[map_val(vec![
            ("year", Value::Int(1817)),
            ("week", Value::Int(1)),
        ])])
        .unwrap();
        assert_eq!(result.to_string(), "1816-12-30T00:00");
    }

    #[test]
    fn test_duration_from_map_extended() {
        let result = eval_duration(&[map_val(vec![
            ("years", Value::Int(1)),
            ("months", Value::Int(2)),
            ("days", Value::Int(3)),
        ])])
        .unwrap();
        // Duration is now returned as Value::Temporal(Duration{...})
        let dur_str = result.to_string();
        assert!(dur_str.starts_with('P'));
        assert!(dur_str.contains('Y')); // Should have years (14 months = 1 year + 2 months)
        assert!(dur_str.contains('D')); // Should have days
    }

    #[test]
    fn test_datetime_fromepoch() {
        let result = eval_datetime_fromepoch(&[Value::Int(0)]).unwrap();
        assert_eq!(result.to_string(), "1970-01-01T00:00Z");
    }

    #[test]
    fn test_datetime_fromepochmillis() {
        let result = eval_datetime_fromepochmillis(&[Value::Int(0)]).unwrap();
        assert_eq!(result.to_string(), "1970-01-01T00:00Z");
    }

    #[test]
    fn test_truncate_date_year() {
        let result = eval_truncate(
            "date",
            &[
                Value::String("year".to_string()),
                Value::String("1984-10-11".to_string()),
            ],
        )
        .unwrap();
        assert_eq!(result.to_string(), "1984-01-01");
    }

    #[test]
    fn test_truncate_date_month() {
        let result = eval_truncate(
            "date",
            &[
                Value::String("month".to_string()),
                Value::String("1984-10-11".to_string()),
            ],
        )
        .unwrap();
        assert_eq!(result.to_string(), "1984-10-01");
    }

    #[test]
    fn test_truncate_datetime_hour() {
        let result = eval_truncate(
            "datetime",
            &[
                Value::String("hour".to_string()),
                Value::String("1984-10-11T12:31:14Z".to_string()),
            ],
        )
        .unwrap();
        assert!(result.to_string().contains("1984-10-11T12:00"));
    }

    #[test]
    fn test_duration_between() {
        let result = eval_duration_between(&[
            Value::String("1984-10-11".to_string()),
            Value::String("1984-10-12".to_string()),
        ])
        .unwrap();
        assert_eq!(result.to_string(), "P1D");
    }

    #[test]
    fn test_duration_in_days() {
        let result = eval_duration_in_days(&[
            Value::String("1984-10-11".to_string()),
            Value::String("1984-10-21".to_string()),
        ])
        .unwrap();
        assert_eq!(result.to_string(), "P10D");
    }

    #[test]
    fn test_duration_in_months() {
        let result = eval_duration_in_months(&[
            Value::String("1984-10-11".to_string()),
            Value::String("1985-01-11".to_string()),
        ])
        .unwrap();
        assert_eq!(result.to_string(), "P3M");
    }

    #[test]
    fn test_duration_in_seconds() {
        let result = eval_duration_in_seconds(&[
            Value::String("1984-10-11T12:00:00".to_string()),
            Value::String("1984-10-11T13:00:00".to_string()),
        ])
        .unwrap();
        assert_eq!(result.to_string(), "PT1H");
    }

    #[test]
    fn test_classify_temporal() {
        assert_eq!(classify_temporal("1984-10-11"), Some(TemporalType::Date));
        assert_eq!(classify_temporal("12:31:14"), Some(TemporalType::LocalTime));
        assert_eq!(
            classify_temporal("12:31:14+01:00"),
            Some(TemporalType::Time)
        );
        assert_eq!(
            classify_temporal("1984-10-11T12:31:14"),
            Some(TemporalType::LocalDateTime)
        );
        assert_eq!(
            classify_temporal("1984-10-11T12:31:14Z"),
            Some(TemporalType::DateTime)
        );
        assert_eq!(
            classify_temporal("1984-10-11T12:31:14+01:00"),
            Some(TemporalType::DateTime)
        );
        assert_eq!(classify_temporal("P1Y2M3D"), Some(TemporalType::Duration));
    }

    #[test]
    fn test_add_months_to_date_clamping() {
        // Jan 31 + 1 month = Feb 28 (non-leap year)
        let date = NaiveDate::from_ymd_opt(2023, 1, 31).unwrap();
        let result = add_months_to_date(date, 1);
        assert_eq!(result, NaiveDate::from_ymd_opt(2023, 2, 28).unwrap());

        // Jan 31 + 1 month in leap year = Feb 29
        let date = NaiveDate::from_ymd_opt(2024, 1, 31).unwrap();
        let result = add_months_to_date(date, 1);
        assert_eq!(result, NaiveDate::from_ymd_opt(2024, 2, 29).unwrap());
    }

    #[test]
    fn test_cypher_duration_multiply() {
        let dur = CypherDuration::new(1, 1, 0);
        let result = dur.multiply(2.0);
        assert_eq!(result.months, 2);
        assert_eq!(result.days, 2);
    }

    #[test]
    fn test_fractional_cascading_in_map() {
        // months: 5.5 cascades via avg Gregorian month (2629746s).
        // 0.5 months = 1314873s = 15 days + 18873s = 15d 5h 14m 33s
        let result = eval_duration(&[map_val(vec![
            ("months", Value::Float(5.5)),
            ("days", Value::Int(0)),
        ])])
        .unwrap();
        let s = result.to_string();
        assert_eq!(s, "P5M15DT5H14M33S");
    }

    #[test]
    fn test_fractional_cascading_full() {
        let result = eval_duration(&[map_val(vec![
            ("years", Value::Float(12.5)),
            ("months", Value::Float(5.5)),
            ("days", Value::Float(14.5)),
            ("hours", Value::Float(16.5)),
            ("minutes", Value::Float(12.5)),
            ("seconds", Value::Float(70.5)),
            ("nanoseconds", Value::Int(3)),
        ])])
        .unwrap();
        let s = result.to_string();
        // Verify roundtrip
        let dur = parse_duration_to_cypher(&s).unwrap();
        assert_eq!(dur.months, 155);
        assert_eq!(dur.days, 29);
    }

    #[test]
    fn test_parse_iso8601_duration_with_weeks() {
        let micros = parse_duration_to_micros("P1W").unwrap();
        assert_eq!(micros, 7 * MICROS_PER_DAY);
    }

    #[test]
    fn test_parse_iso8601_duration_complex() {
        let micros = parse_duration_to_micros("P1DT2H30M").unwrap();
        let expected = MICROS_PER_DAY + 2 * MICROS_PER_HOUR + 30 * MICROS_PER_MINUTE;
        assert_eq!(micros, expected);
    }
}