/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you under the Apache

 *   License, Version 2.0 (the "License"); you may not use this file

 *   except in compliance with the License. You may obtain a copy of

 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .

 */

#pragma once

#include <tools/toolsdllapi.h>

#include <cstdlib>

#include <ostream>

#include <com/sun/star/util/Date.hpp>

namespace com::sun::star::util { struct DateTime; }

enum DayOfWeek { MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY,

                 SATURDAY, SUNDAY };

/** Represents a date in the proleptic Gregorian calendar.

    Largest representable date is 32767-12-31 = 327671231

    Smallest representable date is -32768-01-01 = -327680101

    Due to possible conversions to css::util::Date, which has a short

    Year member variable, these limits are fix.

    Year value 0 is unused. The year before year 1 CE is year 1 BCE, which is

    the traditional proleptic Gregorian calendar.

    This is not how ISO 8601:2000 defines things (but ISO 8601:1998 Draft

    Revision did), but it enables class Date to be used for writing XML files

    as XML Schema Part 2 in D.3.2 No Year Zero says

    "The year "0000" is an illegal year value.", see

    https://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#noYearZero

    and furthermore the note for 3.2.7 dateTime

    https://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#dateTime

 */

class SAL_WARN_UNUSED TOOLS_DLLPUBLIC Date

{

private:

    sal_Int32       mnDate;

    void            setDateFromDMY( sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear );

public:

    enum DateInitSystem

    {

        SYSTEM

    };

    enum DateInitEmpty

    {

        EMPTY

    };

                    explicit Date( DateInitEmpty ) : mnDate(0) {}

                    explicit Date( DateInitSystem );

                    explicit Date( sal_Int32 nDate ) : mnDate(nDate) {}

                    Date( const Date& rDate ) : mnDate(rDate.mnDate) {}

                    /** nDay and nMonth both must be <100, nYear must be != 0 */

                    Date( sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear )

                        { setDateFromDMY(nDay, nMonth, nYear); }

                    explicit Date( const css::util::Date& rUDate )

                    {

                        setDateFromDMY(rUDate.Day, rUDate.Month, rUDate.Year);

                    }

                    explicit Date( const css::util::DateTime& _rDateTime );

    bool            IsEmpty() const { return mnDate == 0; }

    void            SetDate( sal_Int32 nNewDate );

    sal_Int32       GetDate() const { return mnDate; }

    /** Type safe access for values that are guaranteed to be unsigned, like Date::SYSTEM. */

    sal_uInt32      GetDateUnsigned() const { return std::abs(mnDate); }

    css::util::Date GetUNODate() const { return css::util::Date(GetDay(), GetMonth(), GetYear()); }

                    /** nNewDay must be <100 */

    void            SetDay( sal_uInt16 nNewDay );

                    /** nNewMonth must be <100 */

    void            SetMonth( sal_uInt16 nNewMonth );

                    /** nNewYear must be != 0 */

    void            SetYear( sal_Int16 nNewYear );

    sal_uInt16      GetDay() const { return std::abs(mnDate) % 100; }

    sal_uInt16      GetMonth() const { return (std::abs(mnDate) / 100) % 100; }

    sal_Int16       GetYear() const { return mnDate / 10000; }

    /** Type safe access for values that are guaranteed to be unsigned, like Date::SYSTEM. */

    sal_uInt16      GetYearUnsigned() const { return std::abs(GetYear()); }

    sal_Int16       GetNextYear() const { sal_Int16 nY = GetYear(); return nY == -1 ? 1 : nY + 1; }

    sal_Int16       GetPrevYear() const { sal_Int16 nY = GetYear(); return nY == 1 ? -1 : nY - 1; }

    /** Add years skipping year 0 and truncating at limits. If the original

        date was on Feb-29 and the resulting date is not a leap year, the

        result is adjusted to Feb-28.

    */

    void            AddYears( sal_Int16 nAddYears );

    /** Add months skipping year 0 and truncating at limits. If the original

        date was on Feb-29 or day 31 and the resulting date is not a leap year

        or a month with fewer days, the result is adjusted to Feb-28 or day 30.

    */

    void            AddMonths( sal_Int32 nAddMonths );

    /** Add days skipping year 0 and truncating at limits.

     */

    void            AddDays( sal_Int32 nAddDays );

    // Same as AddDays, but returns false on int overflow cases

    [[nodiscard]] bool CheckedAddDays(sal_Int32 nAddDays);

    /** Obtain the day of the week for the date.

        Internally normalizes a copy of values.

        The result may be unexpected for a non-normalized invalid date like

        Date(31,11,2000) or a sequence of aDate.SetDay(31); aDate.SetMonth(11);

     */

    DayOfWeek       GetDayOfWeek() const;

    /** Obtain the day of the year for the date.

        Internally normalizes a copy of values.

        The result may be unexpected for a non-normalized invalid date like

        Date(31,11,2000) or a sequence of aDate.SetDay(31); aDate.SetMonth(11);

     */

    sal_uInt16      GetDayOfYear() const;

    /** Obtain the week of the year for a date.

        @param nMinimumNumberOfDaysInWeek

               How many days of a week must reside in the first week of a year.

        Internally normalizes a copy of values.

        The result may be unexpected for a non-normalized invalid date like

        Date(31,11,2000) or a sequence of aDate.SetDay(31); aDate.SetMonth(11);

     */

    sal_uInt16      GetWeekOfYear( DayOfWeek eStartDay = MONDAY,

                                   sal_Int16 nMinimumNumberOfDaysInWeek = 4 ) const;

    /** Obtain the number of days in the month of the year of the date.

        Internally normalizes a copy of values.

        The result may be unexpected for a non-normalized invalid date like

        Date(31,11,2000) or a sequence of aDate.SetDay(31); aDate.SetMonth(11);

        These would result in 31 as --11-31 rolls over to --12-01 and the

        number of days in December is returned.

        Instead, to obtain the value for the actual set use the static method

        Date::GetDaysInMonth( aDate.GetMonth(), aDate.GetYear()) in such cases.

     */

    sal_uInt16      GetDaysInMonth() const;

    sal_uInt16      GetDaysInYear() const { return (IsLeapYear()) ? 366 : 365; }

    bool            IsLeapYear() const;

    /** If the represented date is valid (1<=month<=12, 1<=day<=(28,29,30,31)

        depending on month/year) AND is of the Gregorian calendar (1582-10-15

        <= date)

     */

    bool            IsValidAndGregorian() const;

    /** If the represented date is valid (1<=month<=12, 1<=day<=(28,29,30,31)

        depending on month/year) */

    bool            IsValidDate() const;

    // Returns true, if the date is the end of the month, false otherwise.

    bool            IsEndOfMonth() const;

    /** Normalize date, invalid day or month values are adapted such that they

        carry over to the next month or/and year, for example 1999-02-32

        becomes 1999-03-04, 1999-13-01 becomes 2000-01-01, 1999-13-42 becomes

        2000-02-11. Truncates at -32768-01-01 or 32767-12-31, 0001-00-x will

        yield the normalized value of -0001-12-x

        This may be necessary after Date ctors or if the SetDate(), SetDay(),

        SetMonth(), SetYear() methods set individual non-matching values.

        Adding/subtracting to/from dates never produces invalid dates.

     */

    void            Normalize();

    bool            IsBetween( const Date& rFrom, const Date& rTo ) const

                        { return ((mnDate >= rFrom.mnDate) &&

                                 (mnDate <= rTo.mnDate)); }

    auto            operator <=> ( const Date& rDate ) const = default;

    Date&           operator =( const Date& rDate )

                        { mnDate = rDate.mnDate; return *this; }

    Date&           operator =( const css::util::Date& rUDate )

                        { setDateFromDMY( rUDate.Day, rUDate.Month, rUDate.Year); return *this; }

    Date&           operator ++();

    Date&           operator --();

    TOOLS_DLLPUBLIC friend Date      operator +( const Date& rDate, sal_Int32 nDays );

    TOOLS_DLLPUBLIC friend Date      operator -( const Date& rDate, sal_Int32 nDays );

    TOOLS_DLLPUBLIC friend sal_Int32 operator -( const Date& rDate1, const Date& rDate2 );

    /** Obtain number of days in a month of a year.

        Internally sanitizes nMonth to values 1 <= nMonth <= 12, does not

        normalize values.

     */

    static sal_uInt16 GetDaysInMonth( sal_uInt16 nMonth, sal_Int16 nYear );

    /// Internally normalizes values.

    static sal_Int32 DateToDays( sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear );

    /// Semantically identical to IsValidDate() member method.

    static bool IsValidDate( sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear );

    /// Semantically identical to IsEndOfMonth() member method.

    static bool IsEndOfMonth(sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear);

    /// Semantically identical to Normalize() member method.

    static bool Normalize( sal_uInt16 & rDay, sal_uInt16 & rMonth, sal_Int16 & rYear );

    /// An accelerated form of DateToDays on this date

    sal_Int32 GetAsNormalizedDays() const;

};

TOOLS_DLLPUBLIC std::ostream& operator<<(std::ostream& os, const Date& rDate);

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