//
// LocalDateTime.h
//
// Library: Foundation
// Package: DateTime
// Module:  LocalDateTime
//
// Definition of the LocalDateTime class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_LocalDateTime_INCLUDED
#define Foundation_LocalDateTime_INCLUDED


#include "Poco/DateTime.h"
#include "Poco/Foundation.h"


namespace Poco
{


class Foundation_API LocalDateTime
/// This class represents an instant in local time
/// (as opposed to UTC), expressed in years, months, days,
/// hours, minutes, seconds and milliseconds based on the
/// Gregorian calendar.
///
/// In addition to the date and time, the class also
/// maintains a time zone differential, which denotes
/// the difference in seconds from UTC to local time,
/// i.e. UTC = local time - time zone differential.
///
/// Although LocalDateTime supports relational and arithmetic
/// operators, all date/time comparisons and date/time arithmetic
/// should be done in UTC, using the DateTime or Timestamp
/// class for better performance. The relational operators
/// normalize the dates/times involved to UTC before carrying out
/// the comparison.
///
/// The time zone differential is based on the input date and
/// time and current time zone. A number of constructors accept
/// an explicit time zone differential parameter. These should
/// not be used since daylight savings time processing is impossible
/// since the time zone is unknown. Each of the constructors
/// accepting a tzd parameter have been marked as deprecated and
/// may be removed in a future revision.
{
public:
    LocalDateTime();
    /// Creates a LocalDateTime with the current date/time
    /// for the current time zone.

    LocalDateTime(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microsecond = 0);
    /// Creates a LocalDateTime for the given Gregorian local date and time.
    ///   * year is from 0 to 9999.
    ///   * month is from 1 to 12.
    ///   * day is from 1 to 31.
    ///   * hour is from 0 to 23.
    ///   * minute is from 0 to 59.
    ///   * second is from 0 to 60 (allowing leap seconds).
    ///   * millisecond is from 0 to 999.
    ///   * microsecond is from 0 to 999.

    //@ deprecated
    LocalDateTime(int tzd, int year, int month, int day, int hour, int minute, int second, int millisecond, int microsecond);
    /// Creates a LocalDateTime for the given Gregorian date and time in the
    /// time zone denoted by the time zone differential in tzd.
    ///   * tzd is in seconds.
    ///   * year is from 0 to 9999.
    ///   * month is from 1 to 12.
    ///   * day is from 1 to 31.
    ///   * hour is from 0 to 23.
    ///   * minute is from 0 to 59.
    ///   * second is from 0 to 60 (allowing leap seconds).
    ///   * millisecond is from 0 to 999.
    ///   * microsecond is from 0 to 999.

    LocalDateTime(const DateTime & dateTime);
    /// Creates a LocalDateTime from the UTC time given in dateTime,
    /// using the time zone differential of the current time zone.

    //@ deprecated
    LocalDateTime(int tzd, const DateTime & dateTime);
    /// Creates a LocalDateTime from the UTC time given in dateTime,
    /// using the given time zone differential. Adjusts dateTime
    /// for the given time zone differential.

    //@ deprecated
    LocalDateTime(int tzd, const DateTime & dateTime, bool adjust);
    /// Creates a LocalDateTime from the UTC time given in dateTime,
    /// using the given time zone differential. If adjust is true,
    /// adjusts dateTime for the given time zone differential.

    LocalDateTime(double julianDay);
    /// Creates a LocalDateTime for the given Julian day in the local time zone.

    //@ deprecated
    LocalDateTime(int tzd, double julianDay);
    /// Creates a LocalDateTime for the given Julian day in the time zone
    /// denoted by the time zone differential in tzd.

    LocalDateTime(const LocalDateTime & dateTime);
    /// Copy constructor. Creates the LocalDateTime from another one.

    ~LocalDateTime();
    /// Destroys the LocalDateTime.

    LocalDateTime & operator=(const LocalDateTime & dateTime);
    /// Assigns another LocalDateTime.

    LocalDateTime & operator=(const Timestamp & timestamp);
    /// Assigns a timestamp

    LocalDateTime & operator=(double julianDay);
    /// Assigns a Julian day in the local time zone.

    LocalDateTime &
    assign(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microseconds = 0);
    /// Assigns a Gregorian local date and time.
    ///   * year is from 0 to 9999.
    ///   * month is from 1 to 12.
    ///   * day is from 1 to 31.
    ///   * hour is from 0 to 23.
    ///   * minute is from 0 to 59.
    ///   * second is from 0 to 60 (allowing leap seconds).
    ///   * millisecond is from 0 to 999.
    ///   * microsecond is from 0 to 999.

    //@ deprecated
    LocalDateTime & assign(int tzd, int year, int month, int day, int hour, int minute, int second, int millisecond, int microseconds);
    /// Assigns a Gregorian local date and time in the time zone denoted by
    /// the time zone differential in tzd.
    ///   * tzd is in seconds.
    ///   * year is from 0 to 9999.
    ///   * month is from 1 to 12.
    ///   * day is from 1 to 31.
    ///   * hour is from 0 to 23.
    ///   * minute is from 0 to 59.
    ///   * second is from 0 to 60 (allowing leap seconds).
    ///   * millisecond is from 0 to 999.
    ///   * microsecond is from 0 to 999.

    //@ deprecated
    LocalDateTime & assign(int tzd, double julianDay);
    /// Assigns a Julian day in the time zone denoted by the
    /// time zone differential in tzd.

    void swap(LocalDateTime & dateTime);
    /// Swaps the LocalDateTime with another one.

    int year() const;
    /// Returns the year.

    int month() const;
    /// Returns the month (1 to 12).

    int week(int firstDayOfWeek = DateTime::MONDAY) const;
    /// Returns the week number within the year.
    /// FirstDayOfWeek should be either SUNDAY (0) or MONDAY (1).
    /// The returned week number will be from 0 to 53. Week number 1 is the week
    /// containing January 4. This is in accordance to ISO 8601.
    ///
    /// The following example assumes that firstDayOfWeek is MONDAY. For 2005, which started
    /// on a Saturday, week 1 will be the week starting on Monday, January 3.
    /// January 1 and 2 will fall within week 0 (or the last week of the previous year).
    ///
    /// For 2007, which starts on a Monday, week 1 will be the week startung on Monday, January 1.
    /// There will be no week 0 in 2007.

    int day() const;
    /// Returns the day within the month (1 to 31).

    int dayOfWeek() const;
    /// Returns the weekday (0 to 6, where
    /// 0 = Sunday, 1 = Monday, ..., 6 = Saturday).

    int dayOfYear() const;
    /// Returns the number of the day in the year.
    /// January 1 is 1, February 1 is 32, etc.

    int hour() const;
    /// Returns the hour (0 to 23).

    int hourAMPM() const;
    /// Returns the hour (0 to 12).

    bool isAM() const;
    /// Returns true if hour < 12;

    bool isPM() const;
    /// Returns true if hour >= 12.

    int minute() const;
    /// Returns the minute (0 to 59).

    int second() const;
    /// Returns the second (0 to 59).

    int millisecond() const;
    /// Returns the millisecond (0 to 999)

    int microsecond() const;
    /// Returns the microsecond (0 to 999)

    double julianDay() const;
    /// Returns the julian day for the date.

    int tzd() const;
    /// Returns the time zone differential.

    DateTime utc() const;
    /// Returns the UTC equivalent for the local date and time.

    Timestamp timestamp() const;
    /// Returns the date and time expressed as a Timestamp.

    Timestamp::UtcTimeVal utcTime() const;
    /// Returns the UTC equivalent for the local date and time.

    bool operator==(const LocalDateTime & dateTime) const;
    bool operator!=(const LocalDateTime & dateTime) const;
    bool operator<(const LocalDateTime & dateTime) const;
    bool operator<=(const LocalDateTime & dateTime) const;
    bool operator>(const LocalDateTime & dateTime) const;
    bool operator>=(const LocalDateTime & dateTime) const;

    LocalDateTime operator+(const Timespan & span) const;
    LocalDateTime operator-(const Timespan & span) const;
    Timespan operator-(const LocalDateTime & dateTime) const;
    LocalDateTime & operator+=(const Timespan & span);
    LocalDateTime & operator-=(const Timespan & span);

protected:
    LocalDateTime(Timestamp::UtcTimeVal utcTime, Timestamp::TimeDiff diff, int tzd);

    void determineTzd(bool adjust = false);
    /// Recalculate the tzd based on the _dateTime member based
    /// on the current timezone using the Standard C runtime functions.
    /// If adjust is true, then adjustForTzd() is called after the
    /// differential is calculated.

    void adjustForTzd();
    /// Adjust the _dateTime member based on the _tzd member.

    std::time_t dstOffset(int & dstOffset) const;
    /// Determine the DST offset for the current date/time.

private:
    DateTime _dateTime;
    int _tzd;

    friend class DateTimeFormatter;
    friend class DateTimeParser;
};


//
// inlines
//
inline int LocalDateTime::year() const
{
    return _dateTime.year();
}


inline int LocalDateTime::month() const
{
    return _dateTime.month();
}


inline int LocalDateTime::week(int firstDayOfWeek) const
{
    return _dateTime.week(firstDayOfWeek);
}


inline int LocalDateTime::day() const
{
    return _dateTime.day();
}


inline int LocalDateTime::dayOfWeek() const
{
    return _dateTime.dayOfWeek();
}


inline int LocalDateTime::dayOfYear() const
{
    return _dateTime.dayOfYear();
}


inline int LocalDateTime::hour() const
{
    return _dateTime.hour();
}


inline int LocalDateTime::hourAMPM() const
{
    return _dateTime.hourAMPM();
}


inline bool LocalDateTime::isAM() const
{
    return _dateTime.isAM();
}


inline bool LocalDateTime::isPM() const
{
    return _dateTime.isPM();
}


inline int LocalDateTime::minute() const
{
    return _dateTime.minute();
}


inline int LocalDateTime::second() const
{
    return _dateTime.second();
}


inline int LocalDateTime::millisecond() const
{
    return _dateTime.millisecond();
}


inline int LocalDateTime::microsecond() const
{
    return _dateTime.microsecond();
}


inline double LocalDateTime::julianDay() const
{
    return _dateTime.julianDay();
}


inline int LocalDateTime::tzd() const
{
    return _tzd;
}


inline Timestamp LocalDateTime::timestamp() const
{
    return Timestamp::fromUtcTime(_dateTime.utcTime());
}


inline Timestamp::UtcTimeVal LocalDateTime::utcTime() const
{
    return _dateTime.utcTime() - ((Timestamp::TimeDiff)_tzd) * 10000000;
}


inline void LocalDateTime::adjustForTzd()
{
    _dateTime += Timespan(((Timestamp::TimeDiff)_tzd) * Timespan::SECONDS);
}


inline void swap(LocalDateTime & d1, LocalDateTime & d2)
{
    d1.swap(d2);
}


} // namespace Poco


#endif // Foundation_LocalDateTime_INCLUDED