// Copyright (C) 2017 The Qt Company Ltd.

// Copyright (C) 2013 John Layt <jlayt@kde.org>

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#ifndef QTIMEZONE_H

#define QTIMEZONE_H

#include <QtCore/qcompare.h>

#include <QtCore/qdatetime.h>

#include <QtCore/qlocale.h>

#include <QtCore/qswap.h>

#include <QtCore/qtclasshelpermacros.h>

#include <chrono>

#if QT_CONFIG(timezone) && (defined(Q_OS_DARWIN) || defined(Q_QDOC))

Q_FORWARD_DECLARE_CF_TYPE(CFTimeZone);

Q_FORWARD_DECLARE_OBJC_CLASS(NSTimeZone);

#endif

QT_BEGIN_NAMESPACE

class QTimeZonePrivate;

class Q_CORE_EXPORT QTimeZone

{

    struct ShortData

    {

#if Q_BYTE_ORDER == Q_LITTLE_ENDIAN

        quintptr mode : 2;

#endif

        qintptr offset : sizeof(void *) * 8 - 2;

#if Q_BYTE_ORDER == Q_BIG_ENDIAN

        quintptr mode : 2;

#endif

        // mode is a cycled Qt::TimeSpec, (int(spec) + 1) % 4, so that zero

        // (lowest bits of a pointer) matches spec being Qt::TimeZone, for which

        // Data holds a QTZP pointer instead of ShortData.

        // Passing Qt::TimeZone gets the equivalent of a null QTZP; it is not short.

        constexpr ShortData(Qt::TimeSpec spec, int secondsAhead = 0)

#if Q_BYTE_ORDER == Q_BIG_ENDIAN

            : offset(spec == Qt::OffsetFromUTC ? secondsAhead : 0),

              mode((int(spec) + 1) & 3)

#else

            : mode((int(spec) + 1) & 3),

              offset(spec == Qt::OffsetFromUTC ? secondsAhead : 0)

#endif

        {

        }

        friend constexpr bool operator==(ShortData lhs, ShortData rhs)

        { return lhs.mode == rhs.mode && lhs.offset == rhs.offset; }

        constexpr Qt::TimeSpec spec() const { return Qt::TimeSpec((mode + 3) & 3); }

    };

    union Data

    {

        Data() noexcept;

        Data(ShortData sd) : s(sd) {}

        Data(const Data &other) noexcept;

        Data(Data &&other) noexcept : d(std::exchange(other.d, nullptr)) {}

        Data &operator=(const Data &other) noexcept;

        Data &operator=(Data &&other) noexcept { swap(other); return *this; }

        ~Data();

        void swap(Data &other) noexcept { qt_ptr_swap(d, other.d); }

        // isShort() is equivalent to s.spec() != Qt::TimeZone

        bool isShort() const { return s.mode; } // a.k.a. quintptr(d) & 3

        // Typse must support: out << wrap("C-strings");

        template <typename Stream, typename Wrap>

        void serialize(Stream &out, const Wrap &wrap) const;

        Data(QTimeZonePrivate *dptr) noexcept;

        Data &operator=(QTimeZonePrivate *dptr) noexcept;

        const QTimeZonePrivate *operator->() const { Q_ASSERT(!isShort()); return d; }

        QTimeZonePrivate *operator->() { Q_ASSERT(!isShort()); return d; }

        QTimeZonePrivate *d = nullptr;

        ShortData s;

    };

    QTimeZone(ShortData sd) : d(sd) {}

public:

    // Sane UTC offsets range from -16 to +16 hours:

    static constexpr int MinUtcOffsetSecs = -16 * 3600;

    // No known modern zone > 12 hrs West of Greenwich.

    // Until 1844, Asia/Manila (in The Philippines) was at 15:56 West.

    static constexpr int MaxUtcOffsetSecs = +16 * 3600;

    // No known modern zone > 14 hrs East of Greenwich.

    // Until 1867, America/Metlakatla (in Alaska) was at 15:13:42 East.

    enum Initialization { LocalTime, UTC };

    QTimeZone() noexcept;

    Q_IMPLICIT QTimeZone(Initialization spec) noexcept

        : d(ShortData(spec == UTC ? Qt::UTC : Qt::LocalTime)) {}

#if QT_CONFIG(timezone)

    explicit QTimeZone(int offsetSeconds);

    explicit QTimeZone(const QByteArray &ianaId);

    QTimeZone(const QByteArray &zoneId, int offsetSeconds, const QString &name,

              const QString &abbreviation, QLocale::Territory territory = QLocale::AnyTerritory,

              const QString &comment = QString());

#endif // timezone backends

    QTimeZone(const QTimeZone &other) noexcept;

    QTimeZone(QTimeZone &&other) noexcept : d(std::move(other.d)) {}

    ~QTimeZone();

    QTimeZone &operator=(const QTimeZone &other);

    QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_PURE_SWAP(QTimeZone)

    void swap(QTimeZone &other) noexcept

    { d.swap(other.d); }

#if QT_CORE_REMOVED_SINCE(6, 7)

    bool operator==(const QTimeZone &other) const;

    bool operator!=(const QTimeZone &other) const;

#endif

    bool isValid() const;

    static QTimeZone fromDurationAheadOfUtc(std::chrono::seconds offset)

    {

        return QTimeZone((offset.count() >= MinUtcOffsetSecs && offset.count() <= MaxUtcOffsetSecs)

                         ? ShortData(offset.count() ? Qt::OffsetFromUTC : Qt::UTC,

                                     int(offset.count()))

                         : ShortData(Qt::TimeZone));

    }

    static QTimeZone fromSecondsAheadOfUtc(int offset)

    {

        return fromDurationAheadOfUtc(std::chrono::seconds{offset});

    }

    constexpr Qt::TimeSpec timeSpec() const noexcept { return d.s.spec(); }

    constexpr int fixedSecondsAheadOfUtc() const noexcept

    { return timeSpec() == Qt::OffsetFromUTC ? int(d.s.offset) : 0; }

    static constexpr bool isUtcOrFixedOffset(Qt::TimeSpec spec) noexcept

    { return spec == Qt::UTC || spec == Qt::OffsetFromUTC; }

    constexpr bool isUtcOrFixedOffset() const noexcept { return isUtcOrFixedOffset(timeSpec()); }

#if QT_CONFIG(timezone)

    QTimeZone asBackendZone() const;

    enum TimeType {

        StandardTime = 0,

        DaylightTime = 1,

        GenericTime = 2

    };

    enum NameType {

        DefaultName = 0,

        LongName = 1,

        ShortName = 2,

        OffsetName = 3

    };

    struct OffsetData {

        QString abbreviation;

        QDateTime atUtc;

        int offsetFromUtc;

        int standardTimeOffset;

        int daylightTimeOffset;

    };

    typedef QList<OffsetData> OffsetDataList;

    bool hasAlternativeName(QByteArrayView alias) const;

    QByteArray id() const;

    QLocale::Territory territory() const;

#  if QT_DEPRECATED_SINCE(6, 6)

    QT_DEPRECATED_VERSION_X_6_6("Use territory() instead")

    QLocale::Country country() const;

#  endif

    QString comment() const;

    QString displayName(const QDateTime &atDateTime, NameType nameType = DefaultName,

                        const QLocale &locale = QLocale()) const;

    QString displayName(TimeType timeType, NameType nameType = DefaultName,

                        const QLocale &locale = QLocale()) const;

    QString abbreviation(const QDateTime &atDateTime) const;

    int offsetFromUtc(const QDateTime &atDateTime) const;

    int standardTimeOffset(const QDateTime &atDateTime) const;

    int daylightTimeOffset(const QDateTime &atDateTime) const;

    bool hasDaylightTime() const;

    bool isDaylightTime(const QDateTime &atDateTime) const;

    OffsetData offsetData(const QDateTime &forDateTime) const;

    bool hasTransitions() const;

    OffsetData nextTransition(const QDateTime &afterDateTime) const;

    OffsetData previousTransition(const QDateTime &beforeDateTime) const;

    OffsetDataList transitions(const QDateTime &fromDateTime, const QDateTime &toDateTime) const;

    static QByteArray systemTimeZoneId();

    static QTimeZone systemTimeZone();

    static QTimeZone utc();

    static bool isTimeZoneIdAvailable(const QByteArray &ianaId);

    static QList<QByteArray> availableTimeZoneIds();

    static QList<QByteArray> availableTimeZoneIds(QLocale::Territory territory);

    static QList<QByteArray> availableTimeZoneIds(int offsetSeconds);

    static QByteArray ianaIdToWindowsId(const QByteArray &ianaId);

    static QByteArray windowsIdToDefaultIanaId(const QByteArray &windowsId);

    static QByteArray windowsIdToDefaultIanaId(const QByteArray &windowsId,

                                               QLocale::Territory territory);

    static QList<QByteArray> windowsIdToIanaIds(const QByteArray &windowsId);

    static QList<QByteArray> windowsIdToIanaIds(const QByteArray &windowsId,

                                                QLocale::Territory territory);

#  if defined(Q_OS_DARWIN) || defined(Q_QDOC)

    static QTimeZone fromCFTimeZone(CFTimeZoneRef timeZone);

    CFTimeZoneRef toCFTimeZone() const Q_DECL_CF_RETURNS_RETAINED;

    static QTimeZone fromNSTimeZone(const NSTimeZone *timeZone);

    NSTimeZone *toNSTimeZone() const Q_DECL_NS_RETURNS_AUTORELEASED;

#  endif

#  if __cpp_lib_chrono >= 201907L || defined(Q_QDOC)

    QT_POST_CXX17_API_IN_EXPORTED_CLASS

    static QTimeZone fromStdTimeZonePtr(const std::chrono::time_zone *timeZone)

    {

        if (!timeZone)

            return QTimeZone();

        const std::string_view timeZoneName = timeZone->name();

        return QTimeZone(QByteArrayView(timeZoneName).toByteArray());

    }

#  endif

#endif // feature timezone

private:

    friend Q_CORE_EXPORT bool comparesEqual(const QTimeZone &lhs, const QTimeZone &rhs) noexcept;

    Q_DECLARE_EQUALITY_COMPARABLE(QTimeZone)

#ifndef QT_NO_DATASTREAM

    friend Q_CORE_EXPORT QDataStream &operator<<(QDataStream &ds, const QTimeZone &tz);

#endif

#ifndef QT_NO_DEBUG_STREAM

    friend Q_CORE_EXPORT QDebug operator<<(QDebug dbg, const QTimeZone &tz);

#endif

    QTimeZone(QTimeZonePrivate &dd);

    friend class QTimeZonePrivate;

    friend class QDateTime;

    friend class QDateTimePrivate;

    Data d;

};

#if QT_CONFIG(timezone)

Q_DECLARE_TYPEINFO(QTimeZone::OffsetData, Q_RELOCATABLE_TYPE);

#endif

Q_DECLARE_SHARED(QTimeZone)

#ifndef QT_NO_DATASTREAM

Q_CORE_EXPORT QDataStream &operator<<(QDataStream &ds, const QTimeZone &tz);

Q_CORE_EXPORT QDataStream &operator>>(QDataStream &ds, QTimeZone &tz);

#endif

#ifndef QT_NO_DEBUG_STREAM

Q_CORE_EXPORT QDebug operator<<(QDebug dbg, const QTimeZone &tz);

#endif

#if QT_CONFIG(timezone) && __cpp_lib_chrono >= 201907L

// zoned_time

template <typename> // QT_POST_CXX17_API_IN_EXPORTED_CLASS

inline QDateTime QDateTime::fromStdZonedTime(const std::chrono::zoned_time<

                                                std::chrono::milliseconds,

                                                const std::chrono::time_zone *

                                             > &time)

{

    const auto sysTime = time.get_sys_time();

    const QTimeZone timeZone = QTimeZone::fromStdTimeZonePtr(time.get_time_zone());

    return fromMSecsSinceEpoch(sysTime.time_since_epoch().count(), timeZone);

}

#endif

QT_END_NAMESPACE

#endif // QTIMEZONE_H