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

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#include <calendar_jewish.hxx>

#include <nativenumbersupplier.hxx>

#include <com/sun/star/i18n/CalendarDisplayCode.hpp>

#include <com/sun/star/i18n/NativeNumberMode.hpp>

using namespace ::com::sun::star::i18n;

namespace i18npool {

// not used

//static UErrorCode status; // status is shared in all calls to Calendar, it has to be reset for each call.

Calendar_jewish::Calendar_jewish()

{

    cCalendar = u"com.sun.star.i18n.Calendar_jewish"_ustr;

}

// The following C++ code is translated from the Lisp code in

// ``Calendrical Calculations'' by Nachum Dershowitz and Edward M. Reingold,

// Software---Practice & Experience, vol. 20, no. 9 (September, 1990),

// pp. 899--928.

// This code is in the public domain, but any use of it

// should acknowledge its source.

// https://web.archive.org/web/20010222054702/http://www.ntu.edu.sg/home/ayxyan/date1.txt

// Hebrew dates

const int HebrewEpoch = -1373429; // Absolute date of start of Hebrew calendar

// True if year is an Hebrew leap year

static bool HebrewLeapYear(sal_Int32 year) {

    return ((((7 * year) + 1) % 19) < 7);

}

// Last month of Hebrew year.

static sal_Int32 LastMonthOfHebrewYear(sal_Int32 year) {

    return  (HebrewLeapYear(year)) ? 13 : 12;

}

// Number of days elapsed from the Sunday prior to the start of the

// Hebrew calendar to the mean conjunction of Tishri of Hebrew year.

static sal_Int32 HebrewCalendarElapsedDays(sal_Int32 year) {

    sal_Int32 MonthsElapsed =

        (235 * ((year - 1) / 19))           // Months in complete cycles so far.

        + (12 * ((year - 1) % 19))          // Regular months in this cycle.

        + (7 * ((year - 1) % 19) + 1) / 19; // Leap months this cycle

    sal_Int32 PartsElapsed = 204 + 793 * (MonthsElapsed % 1080);

    int HoursElapsed =

        5 + 12 * MonthsElapsed + 793 * (MonthsElapsed  / 1080)

        + PartsElapsed / 1080;

    sal_Int32 ConjunctionDay = 1 + 29 * MonthsElapsed + HoursElapsed / 24;

    sal_Int32 ConjunctionParts = 1080 * (HoursElapsed % 24) + PartsElapsed % 1080;

    sal_Int32 AlternativeDay;

    if ((ConjunctionParts >= 19440)        // If new moon is at or after midday,

          || (((ConjunctionDay % 7) == 2)    // ...or is on a Tuesday...

          && (ConjunctionParts >= 9924)  // at 9 hours, 204 parts or later...

          && !(HebrewLeapYear(year)))   // ...of a common year,

          || (((ConjunctionDay % 7) == 1)    // ...or is on a Monday at...

          && (ConjunctionParts >= 16789) // 15 hours, 589 parts or later...

          && (HebrewLeapYear(year - 1))))// at the end of a leap year

        // Then postpone Rosh HaShanah one day

        AlternativeDay = ConjunctionDay + 1;

    else

        AlternativeDay = ConjunctionDay;

    if (((AlternativeDay % 7) == 0)// If Rosh HaShanah would occur on Sunday,

          || ((AlternativeDay % 7) == 3)     // or Wednesday,

          || ((AlternativeDay % 7) == 5))    // or Friday

        // Then postpone it one (more) day

        return (1+ AlternativeDay);

    else

        return AlternativeDay;

}

// Number of days in Hebrew year.

static sal_Int32 DaysInHebrewYear(sal_Int32 year) {

    return ((HebrewCalendarElapsedDays(year + 1)) -

          (HebrewCalendarElapsedDays(year)));

}

// True if Heshvan is long in Hebrew year.

static bool LongHeshvan(sal_Int32 year) {

    return ((DaysInHebrewYear(year) % 10) == 5);

}

// True if Kislev is short in Hebrew year.

static bool ShortKislev(sal_Int32 year) {

    return ((DaysInHebrewYear(year) % 10) == 3);

}

// Last day of month in Hebrew year.

static sal_Int32 LastDayOfHebrewMonth(sal_Int32 month, sal_Int32 year) {

    if ((month == 2)

        || (month == 4)

        || (month == 6)

        || ((month == 8) && !(LongHeshvan(year)))

        || ((month == 9) && ShortKislev(year))

        || (month == 10)

        || ((month == 12) && !(HebrewLeapYear(year)))

        || (month == 13))

        return 29;

    else

        return 30;

}

namespace {

class HebrewDate {

private:

    sal_Int32 year;   // 1...

    sal_Int32 month;  // 1..LastMonthOfHebrewYear(year)

    sal_Int32 day;    // 1..LastDayOfHebrewMonth(month, year)

public:

    HebrewDate(sal_Int32 m, sal_Int32 d, sal_Int32 y) : year(y), month(m), day(d) { }

    explicit HebrewDate(sal_Int32 d) { // Computes the Hebrew date from the absolute date.

    if (d == 730119) // 1999-12-31 : a very common date used in calc

    {

        year = 5760;

        month = 10;

        day = 22;

        return;

    }

    year = (d + HebrewEpoch) / 366; // Approximation from below.

    // Search forward for year from the approximation.

    while (d >= HebrewDate(7,1,year + 1).GetAbsoluteDate())

      year++;

    // Search forward for month from either Tishri or Nisan.

    if (d < HebrewDate(1, 1, year).GetAbsoluteDate())

      month = 7;  //  Start at Tishri

    else

      month = 1;  //  Start at Nisan

    while (d > HebrewDate(month, (LastDayOfHebrewMonth(month,year)), year).GetAbsoluteDate())

      month++;

    // Calculate the day by subtraction.

    day = d - HebrewDate(month, 1, year).GetAbsoluteDate() + 1;

    }

    int GetAbsoluteDate() const { // Computes the absolute date of Hebrew date.

    sal_Int32 DayInYear = day; // Days so far this month.

    if (month < 7) { // Before Tishri, so add days in prior months

             // this year before and after Nisan.

      sal_Int32 m = 7;

      while (m <= (LastMonthOfHebrewYear(year))) {

        DayInYear = DayInYear + LastDayOfHebrewMonth(m, year);

        m++;

      };

      m = 1;

      while (m < month) {

        DayInYear = DayInYear + LastDayOfHebrewMonth(m, year);

        m++;

      }

    }

    else { // Add days in prior months this year

      sal_Int32 m = 7;

      while (m < month) {

        DayInYear = DayInYear + LastDayOfHebrewMonth(m, year);

        m++;

      }

    }

    return (DayInYear +

        (HebrewCalendarElapsedDays(year)// Days in prior years.

         + HebrewEpoch));         // Days elapsed before absolute date 1.

    }

    sal_Int32 GetMonth() const { return month; }

    sal_Int32 GetDay() const { return day; }

    sal_Int32 GetYear() const { return year; }

};

}

//  Gregorian dates

static int LastDayOfGregorianMonth(int month, int year) {

// Compute the last date of the month for the Gregorian calendar.

    switch (month) {

    case 2:

    if ((((year % 4) == 0) && ((year % 100) != 0))

        || ((year % 400) == 0))

      return 29;

    else

      return 28;

    case 4:

    case 6:

    case 9:

    case 11: return 30;

    default: return 31;

    }

}

namespace {

class GregorianDate {

private:

    int year;   // 1...

    int month;  // 1 == January, ..., 12 == December

    int day;    // 1..LastDayOfGregorianMonth(month, year)

public:

    GregorianDate(int m, int d, int y) { month = m; day = d; year = y; }

    explicit GregorianDate(int d) { // Computes the Gregorian date from the absolute date.

        // Search forward year by year from approximate year

        year = d/366;

        while (d >= GregorianDate(1,1,year+1).GetAbsoluteDate())

          year++;

        // Search forward month by month from January

        month = 1;

        while (d > GregorianDate(month, LastDayOfGregorianMonth(month,year), year).GetAbsoluteDate())

          month++;

        day = d - GregorianDate(month,1,year).GetAbsoluteDate() + 1;

    }

    int GetAbsoluteDate() const { // Computes the absolute date from the Gregorian date.

        int N = day;           // days this month

        for (int m = month - 1;  m > 0; m--) // days in prior months this year

          N = N + LastDayOfGregorianMonth(m, year);

        return

          (N                    // days this year

           + 365 * (year - 1)   // days in previous years ignoring leap days

           + (year - 1)/4       // Julian leap days before this year...

           - (year - 1)/100     // ...minus prior century years...

           + (year - 1)/400);   // ...plus prior years divisible by 400

    }

    int GetMonth() const { return month; }

    int GetDay() const { return day; }

    int GetYear() const { return year; }

};

}

// map field value from gregorian calendar to other calendar, it can be overwritten by derived class.

void Calendar_jewish::mapFromGregorian()

{

    int y = fieldValue[CalendarFieldIndex::YEAR];

    if (fieldValue[CalendarFieldIndex::ERA] == 0)

        y = 1 - y;

    GregorianDate Temp(fieldValue[CalendarFieldIndex::MONTH] + 1, fieldValue[CalendarFieldIndex::DAY_OF_MONTH], y);

    HebrewDate hd(Temp.GetAbsoluteDate());

    fieldValue[CalendarFieldIndex::ERA] = hd.GetYear() <= 0 ? 0 : 1;

    fieldValue[CalendarFieldIndex::MONTH] = sal::static_int_cast<sal_Int16>( hd.GetMonth() - 1 );

    fieldValue[CalendarFieldIndex::DAY_OF_MONTH] = static_cast<sal_Int16>(hd.GetDay());

    fieldValue[CalendarFieldIndex::YEAR] = static_cast<sal_Int16>(hd.GetYear() <= 0 ? 1 - hd.GetYear() : hd.GetYear());

}

#define FIELDS  ((1 << CalendarFieldIndex::ERA) | (1 << CalendarFieldIndex::YEAR) | (1 << CalendarFieldIndex::MONTH) | (1 << CalendarFieldIndex::DAY_OF_MONTH))

// map field value from other calendar to gregorian calendar, it should be implemented.

void Calendar_jewish::mapToGregorian()

{

    if (!(fieldSet & FIELDS))

        return;

    sal_Int16 y = fieldSetValue[CalendarFieldIndex::YEAR];

    if (fieldSetValue[CalendarFieldIndex::ERA] == 0)

        y = 1 - y;

    HebrewDate Temp(fieldSetValue[CalendarFieldIndex::MONTH] + 1, fieldSetValue[CalendarFieldIndex::DAY_OF_MONTH], y);

    GregorianDate gd(Temp.GetAbsoluteDate());

    fieldSetValue[CalendarFieldIndex::ERA] = gd.GetYear() <= 0 ? 0 : 1;

    fieldSetValue[CalendarFieldIndex::MONTH] = sal::static_int_cast<sal_Int16>( gd.GetMonth() - 1 );

    fieldSetValue[CalendarFieldIndex::DAY_OF_MONTH] = static_cast<sal_Int16>(gd.GetDay());

    fieldSetValue[CalendarFieldIndex::YEAR] = static_cast<sal_Int16>(gd.GetYear() <= 0 ? 1 - gd.GetYear() : gd.GetYear());

    fieldSet |= FIELDS;

}

// Methods in XExtendedCalendar

OUString SAL_CALL

Calendar_jewish::getDisplayString( sal_Int32 nCalendarDisplayCode, sal_Int16 /*nNativeNumberMode*/ )

{

    const sal_Int16 nNativeNumberMode = NativeNumberMode::NATNUM2;  // make Hebrew number for Jewish calendar

    if (nCalendarDisplayCode == CalendarDisplayCode::SHORT_YEAR) {

        sal_Int32 value = getValue(CalendarFieldIndex::YEAR) % 1000; // take last 3 digits

        return mxNatNum->getNativeNumberString(OUString::number(value), aLocale, nNativeNumberMode );

    }

    else

        return Calendar_gregorian::getDisplayString(nCalendarDisplayCode, nNativeNumberMode );

}

}

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