ladybird/Userland/Libraries/LibJS/Runtime/Temporal/PlainTime.cpp

/*
 * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
 * Copyright (c) 2021-2022, Linus Groh <linusg@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Date.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/Object.h>
#include <LibJS/Runtime/Temporal/AbstractOperations.h>
#include <LibJS/Runtime/Temporal/Calendar.h>
#include <LibJS/Runtime/Temporal/Duration.h>
#include <LibJS/Runtime/Temporal/Instant.h>
#include <LibJS/Runtime/Temporal/PlainDateTime.h>
#include <LibJS/Runtime/Temporal/PlainTime.h>
#include <LibJS/Runtime/Temporal/PlainTimeConstructor.h>
#include <LibJS/Runtime/Temporal/TimeZone.h>
#include <LibJS/Runtime/Temporal/ZonedDateTime.h>

namespace JS::Temporal {

// 4 Temporal.PlainTime Objects, https://tc39.es/proposal-temporal/#sec-temporal-plaintime-objects
PlainTime::PlainTime(u8 iso_hour, u8 iso_minute, u8 iso_second, u16 iso_millisecond, u16 iso_microsecond, u16 iso_nanosecond, Calendar& calendar, Object& prototype)
    : Object(prototype)
    , m_iso_hour(iso_hour)
    , m_iso_minute(iso_minute)
    , m_iso_second(iso_second)
    , m_iso_millisecond(iso_millisecond)
    , m_iso_microsecond(iso_microsecond)
    , m_iso_nanosecond(iso_nanosecond)
    , m_calendar(calendar)
{
}

void PlainTime::visit_edges(Visitor& visitor)
{
    Base::visit_edges(visitor);
    visitor.visit(&m_calendar);
}

// 4.5.1 DifferenceTime ( h1, min1, s1, ms1, mus1, ns1, h2, min2, s2, ms2, mus2, ns2 ), https://tc39.es/proposal-temporal/#sec-temporal-differencetime
TimeDurationRecord difference_time(GlobalObject& global_object, u8 hour1, u8 minute1, u8 second1, u16 millisecond1, u16 microsecond1, u16 nanosecond1, u8 hour2, u8 minute2, u8 second2, u16 millisecond2, u16 microsecond2, u16 nanosecond2)
{
    // 1. Let hours be h2 - h1.
    auto hours = hour2 - hour1;

    // 2. Let minutes be min2 - min1.
    auto minutes = minute2 - minute1;

    // 3. Let seconds be s2 - s1.
    auto seconds = second2 - second1;

    // 4. Let milliseconds be ms2 - ms1.
    auto milliseconds = millisecond2 - millisecond1;

    // 5. Let microseconds be mus2 - mus1.
    auto microseconds = microsecond2 - microsecond1;

    // 6. Let nanoseconds be ns2 - ns1.
    auto nanoseconds = nanosecond2 - nanosecond1;

    // 7. Let sign be ! DurationSign(0, 0, 0, 0, hours, minutes, seconds, milliseconds, microseconds, nanoseconds).
    auto sign = duration_sign(0, 0, 0, 0, hours, minutes, seconds, milliseconds, microseconds, nanoseconds);

    // 8. Let bt be ! BalanceTime(hours × sign, minutes × sign, seconds × sign, milliseconds × sign, microseconds × sign, nanoseconds × sign).
    auto bt = balance_time(hours * sign, minutes * sign, seconds * sign, milliseconds * sign, microseconds * sign, nanoseconds * sign);

    // 9. Assert: bt.[[Days]] is 0.
    VERIFY(bt.days == 0);

    // 10. Return ! CreateTimeDurationRecord(0, bt.[[Hour]] × sign, bt.[[Minute]] × sign, bt.[[Second]] × sign, bt.[[Millisecond]] × sign, bt.[[Microsecond]] × sign, bt.[[Nanosecond]] × sign).
    return MUST(create_time_duration_record(global_object, 0, static_cast<double>(bt.hour * sign), static_cast<double>(bt.minute * sign), static_cast<double>(bt.second * sign), static_cast<double>(bt.millisecond * sign), static_cast<double>(bt.microsecond * sign), static_cast<double>(bt.nanosecond * sign)));
}

// 4.5.2 ToTemporalTime ( item [ , overflow ] ), https://tc39.es/proposal-temporal/#sec-temporal-totemporaltime
ThrowCompletionOr<PlainTime*> to_temporal_time(GlobalObject& global_object, Value item, Optional<StringView> overflow)
{
    auto& vm = global_object.vm();

    // 1. If overflow is not present, set overflow to "constrain".
    if (!overflow.has_value())
        overflow = "constrain"sv;

    // 2. Assert: overflow is either "constrain" or "reject".
    VERIFY(overflow == "constrain"sv || overflow == "reject"sv);

    Optional<TemporalTime> result;

    // 3. If Type(item) is Object, then
    if (item.is_object()) {
        auto& item_object = item.as_object();

        // a. If item has an [[InitializedTemporalTime]] internal slot, then
        if (is<PlainTime>(item_object)) {
            // i. Return item.
            return &static_cast<PlainTime&>(item_object);
        }

        // b. If item has an [[InitializedTemporalZonedDateTime]] internal slot, then
        if (is<ZonedDateTime>(item_object)) {
            auto& zoned_date_time = static_cast<ZonedDateTime&>(item_object);
            // i. Let instant be ! CreateTemporalInstant(item.[[Nanoseconds]]).
            auto* instant = create_temporal_instant(global_object, zoned_date_time.nanoseconds()).release_value();
            // ii. Set plainDateTime to ? BuiltinTimeZoneGetPlainDateTimeFor(item.[[TimeZone]], instant, item.[[Calendar]]).
            auto* plain_date_time = TRY(builtin_time_zone_get_plain_date_time_for(global_object, &zoned_date_time.time_zone(), *instant, zoned_date_time.calendar()));
            // iii. Return ! CreateTemporalTime(plainDateTime.[[ISOHour]], plainDateTime.[[ISOMinute]], plainDateTime.[[ISOSecond]], plainDateTime.[[ISOMillisecond]], plainDateTime.[[ISOMicrosecond]], plainDateTime.[[ISONanosecond]]).
            return TRY(create_temporal_time(global_object, plain_date_time->iso_hour(), plain_date_time->iso_minute(), plain_date_time->iso_second(), plain_date_time->iso_millisecond(), plain_date_time->iso_microsecond(), plain_date_time->iso_nanosecond()));
        }

        // c. If item has an [[InitializedTemporalDateTime]] internal slot, then
        if (is<PlainDateTime>(item_object)) {
            auto& plain_date_time = static_cast<PlainDateTime&>(item_object);
            // i. Return ! CreateTemporalTime(item.[[ISOHour]], item.[[ISOMinute]], item.[[ISOSecond]], item.[[ISOMillisecond]], item.[[ISOMicrosecond]], item.[[ISONanosecond]]).
            return TRY(create_temporal_time(global_object, plain_date_time.iso_hour(), plain_date_time.iso_minute(), plain_date_time.iso_second(), plain_date_time.iso_millisecond(), plain_date_time.iso_microsecond(), plain_date_time.iso_nanosecond()));
        }

        // d. Let calendar be ? GetTemporalCalendarWithISODefault(item).
        auto* calendar = TRY(get_temporal_calendar_with_iso_default(global_object, item_object));

        // e. If ? ToString(calendar) is not "iso8601", then
        auto calendar_identifier = TRY(Value(calendar).to_string(global_object));
        if (calendar_identifier != "iso8601"sv) {
            // i. Throw a RangeError exception.
            return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidCalendarIdentifier, calendar_identifier);
        }

        // f. Let result be ? ToTemporalTimeRecord(item).
        auto unregulated_result = TRY(to_temporal_time_record(global_object, item_object));

        // g. Set result to ? RegulateTime(result.[[Hour]], result.[[Minute]], result.[[Second]], result.[[Millisecond]], result.[[Microsecond]], result.[[Nanosecond]], overflow).
        result = TRY(regulate_time(global_object, *unregulated_result.hour, *unregulated_result.minute, *unregulated_result.second, *unregulated_result.millisecond, *unregulated_result.microsecond, *unregulated_result.nanosecond, *overflow));
    }
    // 4. Else,
    else {
        // a. Let string be ? ToString(item).
        auto string = TRY(item.to_string(global_object));

        // b. Let result be ? ParseTemporalTimeString(string).
        result = TRY(parse_temporal_time_string(global_object, string));

        // c. Assert: IsValidTime(result.[[Hour]], result.[[Minute]], result.[[Second]], result.[[Millisecond]], result.[[Microsecond]], result.[[Nanosecond]]) is true.
        VERIFY(is_valid_time(result->hour, result->minute, result->second, result->millisecond, result->microsecond, result->nanosecond));

        // d. If result.[[Calendar]] is not one of undefined or "iso8601", then
        if (result->calendar.has_value() && *result->calendar != "iso8601"sv) {
            // i. Throw a RangeError exception.
            return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidCalendarIdentifier, *result->calendar);
        }
    }

    // 5. Return ! CreateTemporalTime(result.[[Hour]], result.[[Minute]], result.[[Second]], result.[[Millisecond]], result.[[Microsecond]], result.[[Nanosecond]]).
    return MUST(create_temporal_time(global_object, result->hour, result->minute, result->second, result->millisecond, result->microsecond, result->nanosecond));
}

// 4.5.3 RegulateTime ( hour, minute, second, millisecond, microsecond, nanosecond, overflow ), https://tc39.es/proposal-temporal/#sec-temporal-regulatetime
ThrowCompletionOr<TemporalTime> regulate_time(GlobalObject& global_object, double hour, double minute, double second, double millisecond, double microsecond, double nanosecond, StringView overflow)
{
    auto& vm = global_object.vm();

    // 1. Assert: hour, minute, second, millisecond, microsecond and nanosecond are integers.
    // NOTE: As the spec is currently written this assertion can fail, these are either integers _or_ infinity.
    //       See https://github.com/tc39/proposal-temporal/issues/1672.

    // 2. Assert: overflow is either "constrain" or "reject".
    // NOTE: Asserted by the VERIFY_NOT_REACHED at the end

    // 3. If overflow is "constrain", then
    if (overflow == "constrain"sv) {
        // a. Return ! ConstrainTime(hour, minute, second, millisecond, microsecond, nanosecond).
        return constrain_time(hour, minute, second, millisecond, microsecond, nanosecond);
    }
    // 4. Else,
    else {
        // a. Assert: overflow is "reject".
        VERIFY(overflow == "reject"sv);

        // b. If IsValidTime(hour, minute, second, millisecond, microsecond, nanosecond) is false, throw a RangeError exception.
        if (!is_valid_time(hour, minute, second, millisecond, microsecond, nanosecond))
            return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidPlainTime);

        // c. Return the Record { [[Hour]]: hour, [[Minute]]: minute, [[Second]]: second, [[Millisecond]]: millisecond, [[Microsecond]]: microsecond, [[Nanosecond]]: nanosecond }.
        return TemporalTime { .hour = static_cast<u8>(hour), .minute = static_cast<u8>(minute), .second = static_cast<u8>(second), .millisecond = static_cast<u16>(millisecond), .microsecond = static_cast<u16>(microsecond), .nanosecond = static_cast<u16>(nanosecond) };
    }
}

// 4.5.4 IsValidTime ( hour, minute, second, millisecond, microsecond, nanosecond ), https://tc39.es/proposal-temporal/#sec-temporal-isvalidtime
bool is_valid_time(double hour, double minute, double second, double millisecond, double microsecond, double nanosecond)
{
    // 1. If hour < 0 or hour > 23, then
    if (hour > 23) {
        // a. Return false.
        return false;
    }

    // 2. If minute < 0 or minute > 59, then
    if (minute > 59) {
        // a. Return false.
        return false;
    }

    // 3. If second < 0 or second > 59, then
    if (second > 59) {
        // a. Return false.
        return false;
    }

    // 4. If millisecond < 0 or millisecond > 999, then
    if (millisecond > 999) {
        // a. Return false.
        return false;
    }

    // 5. If microsecond < 0 or microsecond > 999, then
    if (microsecond > 999) {
        // a. Return false.
        return false;
    }

    // 6. If nanosecond < 0 or nanosecond > 999, then
    if (nanosecond > 999) {
        // a. Return false.
        return false;
    }

    // 7. Return true.
    return true;
}

// 4.5.5 BalanceTime ( hour, minute, second, millisecond, microsecond, nanosecond ), https://tc39.es/proposal-temporal/#sec-temporal-balancetime
DaysAndTime balance_time(double hour, double minute, double second, double millisecond, double microsecond, double nanosecond)
{
    // 1. Assert: hour, minute, second, millisecond, microsecond, and nanosecond are integers.
    VERIFY(hour == trunc(hour) && minute == trunc(minute) && second == trunc(second) && millisecond == trunc(millisecond) && microsecond == trunc(microsecond) && nanosecond == trunc(nanosecond));

    // 2. Set microsecond to microsecond + floor(nanosecond / 1000).
    microsecond += floor(nanosecond / 1000);

    // 3. Set nanosecond to nanosecond modulo 1000.
    nanosecond = modulo(nanosecond, 1000);

    // 4. Set millisecond to millisecond + floor(microsecond / 1000).
    millisecond += floor(microsecond / 1000);

    // 5. Set microsecond to microsecond modulo 1000.
    microsecond = modulo(microsecond, 1000);

    // 6. Set second to second + floor(millisecond / 1000).
    second += floor(millisecond / 1000);

    // 7. Set millisecond to millisecond modulo 1000.
    millisecond = modulo(millisecond, 1000);

    // 8. Set minute to minute + floor(second / 60).
    minute += floor(second / 60);

    // 9. Set second to second modulo 60.
    second = modulo(second, 60);

    // 10. Set hour to hour + floor(minute / 60).
    hour += floor(minute / 60);

    // 11. Set minute to minute modulo 60.
    minute = modulo(minute, 60);

    // 12. Let days be floor(hour / 24).
    auto days = floor(hour / 24);

    // 13. Set hour to hour modulo 24.
    hour = modulo(hour, 24);

    // 14. Return the Record { [[Days]]: days, [[Hour]]: hour, [[Minute]]: minute, [[Second]]: second, [[Millisecond]]: millisecond, [[Microsecond]]: microsecond, [[Nanosecond]]: nanosecond }.
    return DaysAndTime {
        .days = static_cast<i32>(days),
        .hour = static_cast<u8>(hour),
        .minute = static_cast<u8>(minute),
        .second = static_cast<u8>(second),
        .millisecond = static_cast<u16>(millisecond),
        .microsecond = static_cast<u16>(microsecond),
        .nanosecond = static_cast<u16>(nanosecond),
    };
}

// 4.5.6 ConstrainTime ( hour, minute, second, millisecond, microsecond, nanosecond ), https://tc39.es/proposal-temporal/#sec-temporal-constraintime
TemporalTime constrain_time(double hour, double minute, double second, double millisecond, double microsecond, double nanosecond)
{
    // 1. Assert: hour, minute, second, millisecond, microsecond, and nanosecond are integers.

    // 2. Set hour to the result of clamping hour between 0 and 23.
    hour = clamp(hour, 0, 23);

    // 3. Set minute to the result of clamping minute between 0 and 59.
    minute = clamp(minute, 0, 59);

    // 4. Set second to the result of clamping second between 0 and 59.
    second = clamp(second, 0, 59);

    // 5. Set millisecond to the result of clamping millisecond between 0 and 999.
    millisecond = clamp(millisecond, 0, 999);

    // 6. Set microsecond to the result of clamping microsecond between 0 and 999.
    microsecond = clamp(microsecond, 0, 999);

    // 7. Set nanosecond to the result of clamping nanosecond between 0 and 999.
    nanosecond = clamp(nanosecond, 0, 999);

    // 8. Return the Record { [[Hour]]: hour, [[Minute]]: minute, [[Second]]: second, [[Millisecond]]: millisecond, [[Microsecond]]: microsecond, [[Nanosecond]]: nanosecond }.
    return TemporalTime { .hour = static_cast<u8>(hour), .minute = static_cast<u8>(minute), .second = static_cast<u8>(second), .millisecond = static_cast<u16>(millisecond), .microsecond = static_cast<u16>(microsecond), .nanosecond = static_cast<u16>(nanosecond) };
}

// 4.5.7 CreateTemporalTime ( hour, minute, second, millisecond, microsecond, nanosecond [ , newTarget ] ), https://tc39.es/proposal-temporal/#sec-temporal-createtemporaltime
ThrowCompletionOr<PlainTime*> create_temporal_time(GlobalObject& global_object, u8 hour, u8 minute, u8 second, u16 millisecond, u16 microsecond, u16 nanosecond, FunctionObject const* new_target)
{
    auto& vm = global_object.vm();

    // 1. Assert: hour, minute, second, millisecond, microsecond and nanosecond are integers.

    // 2. If IsValidTime(hour, minute, second, millisecond, microsecond, nanosecond) is false, throw a RangeError exception.
    if (!is_valid_time(hour, minute, second, millisecond, microsecond, nanosecond))
        return vm.throw_completion<RangeError>(global_object, ErrorType::TemporalInvalidPlainTime);

    // 3. If newTarget is not present, set newTarget to %Temporal.PlainTime%.
    if (!new_target)
        new_target = global_object.temporal_plain_time_constructor();

    // 4. Let object be ? OrdinaryCreateFromConstructor(newTarget, "%Temporal.PlainTime.prototype%", « [[InitializedTemporalTime]], [[ISOHour]], [[ISOMinute]], [[ISOSecond]], [[ISOMillisecond]], [[ISOMicrosecond]], [[ISONanosecond]], [[Calendar]] »).
    // 5. Set object.[[ISOHour]] to hour.
    // 6. Set object.[[ISOMinute]] to minute.
    // 7. Set object.[[ISOSecond]] to second.
    // 8. Set object.[[ISOMillisecond]] to millisecond.
    // 9. Set object.[[ISOMicrosecond]] to microsecond.
    // 10. Set object.[[ISONanosecond]] to nanosecond.
    // 11. Set object.[[Calendar]] to ! GetISO8601Calendar().
    auto* object = TRY(ordinary_create_from_constructor<PlainTime>(global_object, *new_target, &GlobalObject::temporal_plain_time_prototype, hour, minute, second, millisecond, microsecond, nanosecond, *get_iso8601_calendar(global_object)));

    // 12. Return object.
    return object;
}

// 4.5.8 ToTemporalTimeRecord ( temporalTimeLike [ , completeness ] ), https://tc39.es/proposal-temporal/#sec-temporal-totemporaltimerecord
ThrowCompletionOr<TemporalTimeLikeRecord> to_temporal_time_record(GlobalObject& global_object, Object const& temporal_time_like, ToTemporalTimeRecordCompleteness completeness)
{
    auto& vm = global_object.vm();

    // 1. If completeness is not present, set completeness to complete.

    // 2. Let partial be ? PrepareTemporalFields(temporalTimeLike, « "hour", "microsecond", "millisecond", "minute", "nanosecond", "second" », partial).
    auto* partial = TRY(prepare_temporal_fields(global_object, temporal_time_like, { "hour"sv, "microsecond"sv, "millisecond"sv, "minute"sv, "nanosecond"sv, "second"sv }, PrepareTemporalFieldsPartial {}));

    // 3. Let result be a new TemporalTimeLike Record with each field set to undefined.
    auto result = TemporalTimeLikeRecord {};

    // 4. For each row of Table 4, except the header row, in table order, do
    for (auto& [field, property_name] : temporal_time_like_record_fields<TemporalTimeLikeRecord, Optional<double>>(vm)) {
        // a. Let field be the Field Name value of the current row.
        // b. Let propertyName be the Property Name value of the current row.

        // c. Let valueDesc be OrdinaryGetOwnProperty(partial, propertyName).
        auto value_descriptor = MUST(partial->Object::internal_get_own_property(property_name));

        // d. If valueDesc is not undefined, then
        if (value_descriptor.has_value()) {
            // i. Assert: valueDesc is a data Property Descriptor.
            VERIFY(value_descriptor->is_data_descriptor());

            // ii. Set the field of result whose name is field to ℝ(valueDesc.[[Value]]).
            result.*field = value_descriptor->value->as_double();
        }
        // e. Else if completeness is complete, then
        else if (completeness == ToTemporalTimeRecordCompleteness::Complete) {
            // i. Set the field of result whose name is field to 0.
            result.*field = 0;
        }
    }

    // 6. Return result.
    return result;
}

// 4.5.9 TemporalTimeToString ( hour, minute, second, millisecond, microsecond, nanosecond, precision ), https://tc39.es/proposal-temporal/#sec-temporal-temporaltimetostring
String temporal_time_to_string(u8 hour, u8 minute, u8 second, u16 millisecond, u16 microsecond, u16 nanosecond, Variant<StringView, u8> const& precision)
{
    // 1. Assert: hour, minute, second, millisecond, microsecond and nanosecond are integers.

    // 2. Let hour be ToZeroPaddedDecimalString(hour, 2).
    // 3. Let minute be ToZeroPaddedDecimalString(minute, 2).

    // 4. Let seconds be ! FormatSecondsStringPart(second, millisecond, microsecond, nanosecond, precision).
    auto seconds = format_seconds_string_part(second, millisecond, microsecond, nanosecond, precision);

    // 5. Return the string-concatenation of hour, the code unit 0x003A (COLON), minute, and seconds.
    return String::formatted("{:02}:{:02}{}", hour, minute, seconds);
}

// 4.5.10 CompareTemporalTime ( h1, min1, s1, ms1, mus1, ns1, h2, min2, s2, ms2, mus2, ns2 ), https://tc39.es/proposal-temporal/#sec-temporal-comparetemporaltime
i8 compare_temporal_time(u8 hour1, u8 minute1, u8 second1, u16 millisecond1, u16 microsecond1, u16 nanosecond1, u8 hour2, u8 minute2, u8 second2, u16 millisecond2, u16 microsecond2, u16 nanosecond2)
{
    // 1. Assert: h1, min1, s1, ms1, mus1, ns1, h2, min2, s2, ms2, mus2, and ns2 are integers.

    // 2. If h1 > h2, return 1.
    if (hour1 > hour2)
        return 1;

    // 3. If h1 < h2, return -1.
    if (hour1 < hour2)
        return -1;

    // 4. If min1 > min2, return 1.
    if (minute1 > minute2)
        return 1;

    // 5. If min1 < min2, return -1.
    if (minute1 < minute2)
        return -1;

    // 6. If s1 > s2, return 1.
    if (second1 > second2)
        return 1;

    // 7. If s1 < s2, return -1.
    if (second1 < second2)
        return -1;

    // 8. If ms1 > ms2, return 1.
    if (millisecond1 > millisecond2)
        return 1;

    // 9. If ms1 < ms2, return -1.
    if (millisecond1 < millisecond2)
        return -1;

    // 10. If mus1 > mus2, return 1.
    if (microsecond1 > microsecond2)
        return 1;

    // 11. If mus1 < mus2, return -1.
    if (microsecond1 < microsecond2)
        return -1;

    // 12. If ns1 > ns2, return 1.
    if (nanosecond1 > nanosecond2)
        return 1;

    // 13. If ns1 < ns2, return -1.
    if (nanosecond1 < nanosecond2)
        return -1;

    // 14. Return 0.
    return 0;
}

// 4.5.11 AddTime ( hour, minute, second, millisecond, microsecond, nanosecond, hours, minutes, seconds, milliseconds, microseconds, nanoseconds ), https://tc39.es/proposal-temporal/#sec-temporal-addtime
DaysAndTime add_time(u8 hour, u8 minute, u8 second, u16 millisecond, u16 microsecond, u16 nanosecond, double hours, double minutes, double seconds, double milliseconds, double microseconds, double nanoseconds)
{
    // 1. Assert: hour, minute, second, millisecond, microsecond, nanosecond, hours, minutes, seconds, milliseconds, microseconds, and nanoseconds are integers.
    VERIFY(hours == trunc(hours) && minutes == trunc(minutes) && seconds == trunc(seconds) && milliseconds == trunc(milliseconds) && microseconds == trunc(microseconds) && nanoseconds == trunc(nanoseconds));

    // 2. Assert: IsValidTime(hour, minute, second, millisecond, microsecond, nanosecond) is true.
    VERIFY(is_valid_time(hour, minute, second, millisecond, microsecond, nanosecond));

    // 3. Let hour be hour + hours.
    auto hour_ = hour + hours;

    // 4. Let minute be minute + minutes.
    auto minute_ = minute + minutes;

    // 5. Let second be second + seconds.
    auto second_ = second + seconds;

    // 6. Let millisecond be millisecond + milliseconds.
    auto millisecond_ = millisecond + milliseconds;

    // 7. Let microsecond be microsecond + microseconds.
    auto microsecond_ = microsecond + microseconds;

    // 8. Let nanosecond be nanosecond + nanoseconds.
    auto nanosecond_ = nanosecond + nanoseconds;

    // 9. Return ! BalanceTime(hour, minute, second, millisecond, microsecond, nanosecond).
    return balance_time(hour_, minute_, second_, millisecond_, microsecond_, nanosecond_);
}

// 4.5.12 RoundTime ( hour, minute, second, millisecond, microsecond, nanosecond, increment, unit, roundingMode [ , dayLengthNs ] ), https://tc39.es/proposal-temporal/#sec-temporal-roundtime
DaysAndTime round_time(u8 hour, u8 minute, u8 second, u16 millisecond, u16 microsecond, u16 nanosecond, u64 increment, StringView unit, StringView rounding_mode, Optional<double> day_length_ns)
{
    // 1. Assert: hour, minute, second, millisecond, microsecond, nanosecond, and increment are integers.

    // 2. Let fractionalSecond be nanosecond × 10-9 + microsecond × 10-6 + millisecond × 10-3 + second.
    double fractional_second = nanosecond * 0.000000001 + microsecond * 0.000001 + millisecond * 0.001 + second;
    double quantity;

    // 3. If unit is "day", then
    if (unit == "day"sv) {
        // a. If dayLengthNs is not present, set dayLengthNs to nsPerDay.
        if (!day_length_ns.has_value())
            day_length_ns = ns_per_day;

        // b. Let quantity be (((((hour × 60 + minute) × 60 + second) × 1000 + millisecond) × 1000 + microsecond) × 1000 + nanosecond) / dayLengthNs.
        quantity = (((((hour * 60 + minute) * 60 + second) * 1000 + millisecond) * 1000 + microsecond) * 1000 + nanosecond) / *day_length_ns;
    }
    // 4. Else if unit is "hour", then
    else if (unit == "hour"sv) {
        // a. Let quantity be (fractionalSecond / 60 + minute) / 60 + hour.
        quantity = (fractional_second / 60 + minute) / 60 + hour;
    }
    // 5. Else if unit is "minute", then
    else if (unit == "minute"sv) {
        // a. Let quantity be fractionalSecond / 60 + minute.
        quantity = fractional_second / 60 + minute;
    }
    // 6. Else if unit is "second", then
    else if (unit == "second"sv) {
        // a. Let quantity be fractionalSecond.
        quantity = fractional_second;
    }
    // 7. Else if unit is "millisecond", then
    else if (unit == "millisecond"sv) {
        // a. Let quantity be nanosecond × 10-6 + microsecond × 10-3 + millisecond.
        quantity = nanosecond * 0.000001 + 0.001 * microsecond + millisecond;
    }
    // 8. Else if unit is "microsecond", then
    else if (unit == "microsecond"sv) {
        // a. Let quantity be nanosecond × 10-3 + microsecond.
        quantity = nanosecond * 0.001 + microsecond;
    }
    // 9. Else,
    else {
        // a. Assert: unit is "nanosecond".
        VERIFY(unit == "nanosecond"sv);

        // b. Let quantity be nanosecond.
        quantity = nanosecond;
    }

    // 10. Let result be RoundNumberToIncrement(quantity, increment, roundingMode).
    auto result = round_number_to_increment(quantity, increment, rounding_mode);

    // If unit is "day", then
    if (unit == "day"sv) {
        // a. Return the Record { [[Days]]: result, [[Hour]]: 0, [[Minute]]: 0, [[Second]]: 0, [[Millisecond]]: 0, [[Microsecond]]: 0, [[Nanosecond]]: 0 }.
        return DaysAndTime { .days = (i32)result, .hour = 0, .minute = 0, .second = 0, .millisecond = 0, .microsecond = 0, .nanosecond = 0 };
    }

    // 12. If unit is "hour", then
    if (unit == "hour"sv) {
        // a. Return ! BalanceTime(result, 0, 0, 0, 0, 0).
        return balance_time(result, 0, 0, 0, 0, 0);
    }

    // 13. If unit is "minute", then
    if (unit == "minute"sv) {
        // a. Return ! BalanceTime(hour, result, 0, 0, 0, 0).
        return balance_time(hour, result, 0, 0, 0, 0);
    }

    // 14. If unit is "second", then
    if (unit == "second"sv) {
        // a. Return ! BalanceTime(hour, minute, result, 0, 0, 0).
        return balance_time(hour, minute, result, 0, 0, 0);
    }

    // 15. If unit is "millisecond", then
    if (unit == "millisecond"sv) {
        // a. Return ! BalanceTime(hour, minute, second, result, 0, 0).
        return balance_time(hour, minute, second, result, 0, 0);
    }

    // 16. If unit is "microsecond", then
    if (unit == "microsecond"sv) {
        // a. Return ! BalanceTime(hour, minute, second, millisecond, result, 0).
        return balance_time(hour, minute, second, millisecond, result, 0);
    }

    // 17. Assert: unit is "nanosecond".
    VERIFY(unit == "nanosecond"sv);

    // 18. Return ! BalanceTime(hour, minute, second, millisecond, microsecond, result).
    return balance_time(hour, minute, second, millisecond, microsecond, result);
}

// 4.5.13 DifferenceTemporalPlainTime ( operation, temporalTime, other, options ), https://tc39.es/proposal-temporal/#sec-temporal-differencetemporalplaintime
ThrowCompletionOr<Duration*> difference_temporal_plain_time(GlobalObject& global_object, DifferenceOperation operation, PlainTime const& temporal_time, Value other_value, Value options_value)
{
    // 1. If operation is since, let sign be -1. Otherwise, let sign be 1.
    i8 sign = operation == DifferenceOperation::Since ? -1 : 1;

    // 2. Set other to ? ToTemporalTime(other).
    auto* other = TRY(to_temporal_time(global_object, other_value));

    // 3. Let settings be ? GetDifferenceSettings(operation, options, time, « », "nanosecond", "hour").
    auto settings = TRY(get_difference_settings(global_object, operation, options_value, UnitGroup::Time, {}, { "nanosecond"sv }, "hour"sv));

    // 4. Let result be ! DifferenceTime(temporalTime.[[ISOHour]], temporalTime.[[ISOMinute]], temporalTime.[[ISOSecond]], temporalTime.[[ISOMillisecond]], temporalTime.[[ISOMicrosecond]], temporalTime.[[ISONanosecond]], other.[[ISOHour]], other.[[ISOMinute]], other.[[ISOSecond]], other.[[ISOMillisecond]], other.[[ISOMicrosecond]], other.[[ISONanosecond]]).
    auto result = difference_time(global_object, temporal_time.iso_hour(), temporal_time.iso_minute(), temporal_time.iso_second(), temporal_time.iso_millisecond(), temporal_time.iso_microsecond(), temporal_time.iso_nanosecond(), other->iso_hour(), other->iso_minute(), other->iso_second(), other->iso_millisecond(), other->iso_microsecond(), other->iso_nanosecond());

    // 5. Set result to (! RoundDuration(0, 0, 0, 0, result.[[Hours]], result.[[Minutes]], result.[[Seconds]], result.[[Milliseconds]], result.[[Microseconds]], result.[[Nanoseconds]], settings.[[RoundingIncrement]], settings.[[SmallestUnit]], settings.[[RoundingMode]])).[[DurationRecord]].
    auto rounded_result = MUST(round_duration(global_object, 0, 0, 0, 0, result.hours, result.minutes, result.seconds, result.milliseconds, result.microseconds, result.nanoseconds, settings.rounding_increment, settings.smallest_unit, settings.rounding_mode)).duration_record;

    // 6. Set result to ! BalanceDuration(0, result.[[Hours]], result.[[Minutes]], result.[[Seconds]], result.[[Milliseconds]], result.[[Microseconds]], result.[[Nanoseconds]], settings.[[LargestUnit]]).
    result = MUST(balance_duration(global_object, 0, rounded_result.hours, rounded_result.minutes, rounded_result.seconds, rounded_result.milliseconds, rounded_result.microseconds, Crypto::SignedBigInteger { (i32)rounded_result.nanoseconds }, settings.largest_unit));

    // 7. Return ! CreateTemporalDuration(0, 0, 0, 0, sign × result.[[Hours]], sign × result.[[Minutes]], sign × result.[[Seconds]], sign × result.[[Milliseconds]], sign × result.[[Microseconds]], sign × result.[[Nanoseconds]]).
    return MUST(create_temporal_duration(global_object, 0, 0, 0, 0, sign * result.hours, sign * result.minutes, sign * result.seconds, sign * result.milliseconds, sign * result.microseconds, sign * result.nanoseconds));
}

// 4.5.14 AddDurationToOrSubtractDurationFromPlainTime ( operation, temporalTime, temporalDurationLike ), https://tc39.es/proposal-temporal/#sec-temporal-adddurationtoorsubtractdurationfromplaintime
ThrowCompletionOr<PlainTime*> add_duration_to_or_subtract_duration_from_plain_time(GlobalObject& global_object, ArithmeticOperation operation, PlainTime const& temporal_time, Value temporal_duration_like)
{
    // 1. If operation is subtract, let sign be -1. Otherwise, let sign be 1.
    i8 sign = operation == ArithmeticOperation::Subtract ? -1 : 1;

    // 2. Let duration be ? ToTemporalDurationRecord(temporalDurationLike).
    auto duration = TRY(to_temporal_duration_record(global_object, temporal_duration_like));

    // 3. Let result be ! AddTime(temporalTime.[[ISOHour]], temporalTime.[[ISOMinute]], temporalTime.[[ISOSecond]], temporalTime.[[ISOMillisecond]], temporalTime.[[ISOMicrosecond]], temporalTime.[[ISONanosecond]], sign × duration.[[Hours]], sign × duration.[[Minutes]], sign × duration.[[Seconds]], sign × duration.[[Milliseconds]], sign × duration.[[Microseconds]], sign × duration.[[Nanoseconds]]).
    auto result = add_time(temporal_time.iso_hour(), temporal_time.iso_minute(), temporal_time.iso_second(), temporal_time.iso_millisecond(), temporal_time.iso_microsecond(), temporal_time.iso_nanosecond(), sign * duration.hours, sign * duration.minutes, sign * duration.seconds, sign * duration.milliseconds, sign * duration.microseconds, sign * duration.nanoseconds);

    // 4. Assert: IsValidTime(result.[[Hour]], result.[[Minute]], result.[[Second]], result.[[Millisecond]], result.[[Microsecond]], result.[[Nanosecond]]) is true.
    VERIFY(is_valid_time(result.hour, result.minute, result.second, result.millisecond, result.microsecond, result.nanosecond));

    // 5. Return ! CreateTemporalTime(result.[[Hour]], result.[[Minute]], result.[[Second]], result.[[Millisecond]], result.[[Microsecond]], result.[[Nanosecond]]).
    return MUST(create_temporal_time(global_object, result.hour, result.minute, result.second, result.millisecond, result.microsecond, result.nanosecond));
}

}