// © 2016 and later: Unicode, Inc. and others.

// License & terms of use: http://www.unicode.org/copyright.html

/*

 * Copyright (C) 2003-2014, International Business Machines Corporation

 * and others. All Rights Reserved.

 ******************************************************************************

 *

 * File INDIANCAL.CPP

 *****************************************************************************

 */

#include "indiancal.h"

#include <stdlib.h>

#if !UCONFIG_NO_FORMATTING

#include "mutex.h"

#include <float.h>

#include "gregoimp.h" // Math

#include "astro.h" // CalendarAstronomer

#include "uhash.h"

// Debugging

#ifdef U_DEBUG_INDIANCAL

#include <stdio.h>

#include <stdarg.h>

#endif

U_NAMESPACE_BEGIN

// Implementation of the IndianCalendar class

//-------------------------------------------------------------------------

// Constructors...

//-------------------------------------------------------------------------

Calendar* IndianCalendar::clone() const {

  return new IndianCalendar(*this);

}

IndianCalendar::IndianCalendar(const Locale& aLocale, UErrorCode& success)

  :   Calendar(TimeZone::createDefault(), aLocale, success)

{

  setTimeInMillis(getNow(), success); // Call this again now that the vtable is set up properly.

}

IndianCalendar::IndianCalendar(const IndianCalendar& other) : Calendar(other) {

}

IndianCalendar::~IndianCalendar()

{

}

const char *IndianCalendar::getType() const { 

   return "indian";

}

static const int32_t LIMITS[UCAL_FIELD_COUNT][4] = {

    // Minimum  Greatest     Least   Maximum

    //           Minimum   Maximum

    {        0,        0,        0,        0}, // ERA

    { -5000000, -5000000,  5000000,  5000000}, // YEAR

    {        0,        0,       11,       11}, // MONTH

    {        1,        1,       52,       53}, // WEEK_OF_YEAR

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // WEEK_OF_MONTH

    {        1,        1,       30,       31}, // DAY_OF_MONTH

    {        1,        1,      365,      366}, // DAY_OF_YEAR

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DAY_OF_WEEK

    {       -1,       -1,        5,        5}, // DAY_OF_WEEK_IN_MONTH

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // AM_PM

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // HOUR_OF_DAY

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MINUTE

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // SECOND

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECOND

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // ZONE_OFFSET

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DST_OFFSET

    { -5000000, -5000000,  5000000,  5000000}, // YEAR_WOY

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // DOW_LOCAL

    { -5000000, -5000000,  5000000,  5000000}, // EXTENDED_YEAR

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // JULIAN_DAY

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // MILLISECONDS_IN_DAY

    {/*N/A*/-1,/*N/A*/-1,/*N/A*/-1,/*N/A*/-1}, // IS_LEAP_MONTH

};

static const double JULIAN_EPOCH = 1721425.5;

static const int32_t INDIAN_ERA_START  = 78;

static const int32_t INDIAN_YEAR_START = 80;

int32_t IndianCalendar::handleGetLimit(UCalendarDateFields field, ELimitType limitType) const {

  return LIMITS[field][limitType];

}

/*

 * Determine whether the given gregorian year is a Leap year 

 */

static UBool isGregorianLeap(int32_t year)

{

    return ((year % 4) == 0) && (!(((year % 100) == 0) && ((year % 400) != 0))); 

}

//----------------------------------------------------------------------

// Calendar framework

//----------------------------------------------------------------------

/*

 * Return the length (in days) of the given month.

 *

 * @param eyear  The year in Saka Era

 * @param month  The month(0-based) in Indian calendar

 */

int32_t IndianCalendar::handleGetMonthLength(int32_t eyear, int32_t month) const {

   if (month < 0 || month > 11) {

      eyear += ClockMath::floorDivide(month, 12, month);

   }

   if (isGregorianLeap(eyear + INDIAN_ERA_START) && month == 0) {

       return 31;

   }

   if (month >= 1 && month <= 5) {

       return 31;

   }

   return 30;

}

/*

 * Return the number of days in the given Indian year

 *

 * @param eyear The year in Saka Era.

 */

int32_t IndianCalendar::handleGetYearLength(int32_t eyear) const {

    return isGregorianLeap(eyear + INDIAN_ERA_START) ? 366 : 365;

}

/*

 * Returns the Julian Day corresponding to gregorian date

 *

 * @param year The Gregorian year

 * @param month The month in Gregorian Year

 * @param date The date in Gregorian day in month

 */

static double gregorianToJD(int32_t year, int32_t month, int32_t date) {

   double julianDay = (JULIAN_EPOCH - 1) +

      (365 * (year - 1)) +

      uprv_floor((year - 1) / 4) +

      (-uprv_floor((year - 1) / 100)) +

      uprv_floor((year - 1) / 400) +

      uprv_floor((((367 * month) - 362) / 12) +

            ((month <= 2) ? 0 :

             (isGregorianLeap(year) ? -1 : -2)

            ) +

            date);

   return julianDay;

}

/*

 * Returns the Gregorian Date corresponding to a given Julian Day

 * @param jd The Julian Day

 */

static int32_t* jdToGregorian(double jd, int32_t gregorianDate[3]) {

   double wjd, depoch, quadricent, dqc, cent, dcent, quad, dquad, yindex, yearday, leapadj;

   int32_t year, month, day;

   wjd = uprv_floor(jd - 0.5) + 0.5;

   depoch = wjd - JULIAN_EPOCH;

   quadricent = uprv_floor(depoch / 146097);

   dqc = (int32_t)uprv_floor(depoch) % 146097;

   cent = uprv_floor(dqc / 36524);

   dcent = (int32_t)uprv_floor(dqc) % 36524;

   quad = uprv_floor(dcent / 1461);

   dquad = (int32_t)uprv_floor(dcent) % 1461;

   yindex = uprv_floor(dquad / 365);

   year = (int32_t)((quadricent * 400) + (cent * 100) + (quad * 4) + yindex);

   if (!((cent == 4) || (yindex == 4))) {

      year++;

   }

   yearday = wjd - gregorianToJD(year, 1, 1);

   leapadj = ((wjd < gregorianToJD(year, 3, 1)) ? 0

         :

         (isGregorianLeap(year) ? 1 : 2)

         );

   month = (int32_t)uprv_floor((((yearday + leapadj) * 12) + 373) / 367);

   day = (int32_t)(wjd - gregorianToJD(year, month, 1)) + 1;

   gregorianDate[0] = year;

   gregorianDate[1] = month;

   gregorianDate[2] = day;

   return gregorianDate;

}

//-------------------------------------------------------------------------

// Functions for converting from field values to milliseconds....

//-------------------------------------------------------------------------

static double IndianToJD(int32_t year, int32_t month, int32_t date) {

   int32_t leapMonth, gyear, m;

   double start, jd;

   gyear = year + INDIAN_ERA_START;

   if(isGregorianLeap(gyear)) {

      leapMonth = 31;

      start = gregorianToJD(gyear, 3, 21);

   } 

   else {

      leapMonth = 30;

      start = gregorianToJD(gyear, 3, 22);

   }

   if (month == 1) {

      jd = start + (date - 1);

   } else {

      jd = start + leapMonth;

      m = month - 2;

      //m = Math.min(m, 5);

      if (m > 5) {

          m = 5;

      }

      jd += m * 31;

      if (month >= 8) {

         m = month - 7;

         jd += m * 30;

      }

      jd += date - 1;

   }

   return jd;

}

/*

 * Return JD of start of given month/year of Indian Calendar

 * @param eyear The year in Indian Calendar measured from Saka Era (78 AD).

 * @param month The month in Indian calendar

 */

int32_t IndianCalendar::handleComputeMonthStart(int32_t eyear, int32_t month, UBool /* useMonth */ ) const {

   //month is 0 based; converting it to 1-based 

   int32_t imonth;

    // If the month is out of range, adjust it into range, and adjust the extended eyar accordingly

   if (month < 0 || month > 11) {

      eyear += (int32_t)ClockMath::floorDivide(month, 12, month);

   }

   if(month == 12){

       imonth = 1;

   } else {

       imonth = month + 1; 

   }

   double jd = IndianToJD(eyear ,imonth, 1);

   return (int32_t)jd;

}

//-------------------------------------------------------------------------

// Functions for converting from milliseconds to field values

//-------------------------------------------------------------------------

int32_t IndianCalendar::handleGetExtendedYear() {

    int32_t year;

    if (newerField(UCAL_EXTENDED_YEAR, UCAL_YEAR) == UCAL_EXTENDED_YEAR) {

        year = internalGet(UCAL_EXTENDED_YEAR, 1); // Default to year 1

    } else {

        year = internalGet(UCAL_YEAR, 1); // Default to year 1

    }

    return year;

}

/*

 * Override Calendar to compute several fields specific to the Indian

 * calendar system.  These are:

 *

 * <ul><li>ERA

 * <li>YEAR

 * <li>MONTH

 * <li>DAY_OF_MONTH

 * <li>EXTENDED_YEAR</ul>

 * 

 * The DAY_OF_WEEK and DOW_LOCAL fields are already set when this

 * method is called. The getGregorianXxx() methods return Gregorian

 * calendar equivalents for the given Julian day.

 */

void IndianCalendar::handleComputeFields(int32_t julianDay, UErrorCode&  /* status */) {

    double jdAtStartOfGregYear;

    int32_t leapMonth, IndianYear, yday, IndianMonth, IndianDayOfMonth, mday;

    int32_t gregorianYear;      // Stores gregorian date corresponding to Julian day;

    int32_t gd[3];

    gregorianYear = jdToGregorian(julianDay, gd)[0];          // Gregorian date for Julian day

    IndianYear = gregorianYear - INDIAN_ERA_START;            // Year in Saka era

    jdAtStartOfGregYear = gregorianToJD(gregorianYear, 1, 1); // JD at start of Gregorian year

    yday = (int32_t)(julianDay - jdAtStartOfGregYear);        // Day number in Gregorian year (starting from 0)

    if (yday < INDIAN_YEAR_START) {

        // Day is at the end of the preceding Saka year

        IndianYear -= 1;

        leapMonth = isGregorianLeap(gregorianYear - 1) ? 31 : 30; // Days in leapMonth this year, previous Gregorian year

        yday += leapMonth + (31 * 5) + (30 * 3) + 10;

    } else {

        leapMonth = isGregorianLeap(gregorianYear) ? 31 : 30; // Days in leapMonth this year

        yday -= INDIAN_YEAR_START;

    }

    if (yday < leapMonth) {

        IndianMonth = 0;

        IndianDayOfMonth = yday + 1;

    } else {

        mday = yday - leapMonth;

        if (mday < (31 * 5)) {

            IndianMonth = (int32_t)uprv_floor(mday / 31) + 1;

            IndianDayOfMonth = (mday % 31) + 1;

        } else {

            mday -= 31 * 5;

            IndianMonth = (int32_t)uprv_floor(mday / 30) + 6;

            IndianDayOfMonth = (mday % 30) + 1;

        }

   }

   internalSet(UCAL_ERA, 0);

   internalSet(UCAL_EXTENDED_YEAR, IndianYear);

   internalSet(UCAL_YEAR, IndianYear);

   internalSet(UCAL_MONTH, IndianMonth);

   internalSet(UCAL_DAY_OF_MONTH, IndianDayOfMonth);

   internalSet(UCAL_DAY_OF_YEAR, yday + 1); // yday is 0-based

}    

UBool

IndianCalendar::inDaylightTime(UErrorCode& status) const

{

    // copied from GregorianCalendar

    if (U_FAILURE(status) || !getTimeZone().useDaylightTime()) {

        return FALSE;

    }

    // Force an update of the state of the Calendar.

    ((IndianCalendar*)this)->complete(status); // cast away const

    return (UBool)(U_SUCCESS(status) ? (internalGet(UCAL_DST_OFFSET) != 0) : FALSE);

}

// default century

const UDate     IndianCalendar::fgSystemDefaultCentury          = DBL_MIN;

const int32_t   IndianCalendar::fgSystemDefaultCenturyYear      = -1;

UDate           IndianCalendar::fgSystemDefaultCenturyStart     = DBL_MIN;

int32_t         IndianCalendar::fgSystemDefaultCenturyStartYear = -1;

UBool IndianCalendar::haveDefaultCentury() const

{

    return TRUE;

}

UDate IndianCalendar::defaultCenturyStart() const

{

    return internalGetDefaultCenturyStart();

}

int32_t IndianCalendar::defaultCenturyStartYear() const

{

    return internalGetDefaultCenturyStartYear();

}

UDate

IndianCalendar::internalGetDefaultCenturyStart() const

{

    // lazy-evaluate systemDefaultCenturyStart

    UBool needsUpdate;

    { 

        Mutex m;

        needsUpdate = (fgSystemDefaultCenturyStart == fgSystemDefaultCentury);

    }

    if (needsUpdate) {

        initializeSystemDefaultCentury();

    }

    // use defaultCenturyStart unless it's the flag value;

    // then use systemDefaultCenturyStart

    return fgSystemDefaultCenturyStart;

}

int32_t

IndianCalendar::internalGetDefaultCenturyStartYear() const

{

    // lazy-evaluate systemDefaultCenturyStartYear

    UBool needsUpdate;

    { 

        Mutex m;

        needsUpdate = (fgSystemDefaultCenturyStart == fgSystemDefaultCentury);

    }

    if (needsUpdate) {

        initializeSystemDefaultCentury();

    }

    // use defaultCenturyStart unless it's the flag value;

    // then use systemDefaultCenturyStartYear

    return    fgSystemDefaultCenturyStartYear;

}

void

IndianCalendar::initializeSystemDefaultCentury()

{

    // initialize systemDefaultCentury and systemDefaultCenturyYear based

    // on the current time.  They'll be set to 80 years before

    // the current time.

    // No point in locking as it should be idempotent.

    if (fgSystemDefaultCenturyStart == fgSystemDefaultCentury) {

        UErrorCode status = U_ZERO_ERROR;

        IndianCalendar calendar(Locale("@calendar=Indian"),status);

        if (U_SUCCESS(status)) {

            calendar.setTime(Calendar::getNow(), status);

            calendar.add(UCAL_YEAR, -80, status);

            UDate    newStart = calendar.getTime(status);

            int32_t  newYear  = calendar.get(UCAL_YEAR, status);

            {

                Mutex m;

                fgSystemDefaultCenturyStart = newStart;

                fgSystemDefaultCenturyStartYear = newYear;

            }

        }

        // We have no recourse upon failure unless we want to propagate the failure

        // out.

    }

}

UOBJECT_DEFINE_RTTI_IMPLEMENTATION(IndianCalendar)

U_NAMESPACE_END

#endif