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

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

/*

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

 * Copyright (C) 2013, International Business Machines Corporation

 * and others. All Rights Reserved.

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

 *

 * File DANGICAL.CPP

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

 */

#include "chnsecal.h"

#include "dangical.h"

#if !UCONFIG_NO_FORMATTING

#include "gregoimp.h" // Math

#include "uassert.h"

#include "ucln_in.h"

#include "umutex.h"

#include "unicode/rbtz.h"

#include "unicode/tzrule.h"

// --- The cache --

static icu::TimeZone *gDangiCalendarZoneAstroCalc = NULL;

static icu::UInitOnce gDangiCalendarInitOnce = U_INITONCE_INITIALIZER;

/**

 * The start year of the Korean traditional calendar (Dan-gi) is the inaugural

 * year of Dan-gun (BC 2333).

 */

static const int32_t DANGI_EPOCH_YEAR = -2332; // Gregorian year

U_CDECL_BEGIN

static UBool calendar_dangi_cleanup(void) {

    if (gDangiCalendarZoneAstroCalc) {

        delete gDangiCalendarZoneAstroCalc;

        gDangiCalendarZoneAstroCalc = NULL;

    }

    gDangiCalendarInitOnce.reset();

    return TRUE;

}

U_CDECL_END

U_NAMESPACE_BEGIN

// Implementation of the DangiCalendar class

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

// Constructors...

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

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

:   ChineseCalendar(aLocale, DANGI_EPOCH_YEAR, getDangiCalZoneAstroCalc(), success)

{

}

DangiCalendar::DangiCalendar (const DangiCalendar& other) 

: ChineseCalendar(other)

{

}

DangiCalendar::~DangiCalendar()

{

}

DangiCalendar*

DangiCalendar::clone() const

{

    return new DangiCalendar(*this);

}

const char *DangiCalendar::getType() const { 

    return "dangi";

}

/**

 * The time zone used for performing astronomical computations for

 * Dangi calendar. In Korea various timezones have been used historically 

 * (cf. http://www.math.snu.ac.kr/~kye/others/lunar.html): 

 *  

 *            - 1908/04/01: GMT+8 

 * 1908/04/01 - 1911/12/31: GMT+8.5 

 * 1912/01/01 - 1954/03/20: GMT+9 

 * 1954/03/21 - 1961/08/09: GMT+8.5 

 * 1961/08/10 -           : GMT+9 

 *  

 * Note that, in 1908-1911, the government did not apply the timezone change 

 * but used GMT+8. In addition, 1954-1961's timezone change does not affect 

 * the lunar date calculation. Therefore, the following simpler rule works: 

 *   

 * -1911: GMT+8 

 * 1912-: GMT+9 

 *  

 * Unfortunately, our astronomer's approximation doesn't agree with the 

 * references (http://www.math.snu.ac.kr/~kye/others/lunar.html and 

 * http://astro.kasi.re.kr/Life/ConvertSolarLunarForm.aspx?MenuID=115) 

 * in 1897/7/30. So the following ad hoc fix is used here: 

 *  

 *     -1896: GMT+8 

 *      1897: GMT+7 

 * 1898-1911: GMT+8 

 * 1912-    : GMT+9 

 */

static void U_CALLCONV initDangiCalZoneAstroCalc(void) {

    U_ASSERT(gDangiCalendarZoneAstroCalc == NULL);

    const UDate millis1897[] = { (UDate)((1897 - 1970) * 365 * kOneDay) }; // some days of error is not a problem here

    const UDate millis1898[] = { (UDate)((1898 - 1970) * 365 * kOneDay) }; // some days of error is not a problem here

    const UDate millis1912[] = { (UDate)((1912 - 1970) * 365 * kOneDay) }; // this doesn't create an issue for 1911/12/20

    InitialTimeZoneRule* initialTimeZone = new InitialTimeZoneRule(UNICODE_STRING_SIMPLE("GMT+8"), 8*kOneHour, 0);

    TimeZoneRule* rule1897 = new TimeArrayTimeZoneRule(UNICODE_STRING_SIMPLE("Korean 1897"), 7*kOneHour, 0, millis1897, 1, DateTimeRule::STANDARD_TIME);

    TimeZoneRule* rule1898to1911 = new TimeArrayTimeZoneRule(UNICODE_STRING_SIMPLE("Korean 1898-1911"), 8*kOneHour, 0, millis1898, 1, DateTimeRule::STANDARD_TIME);

    TimeZoneRule* ruleFrom1912 = new TimeArrayTimeZoneRule(UNICODE_STRING_SIMPLE("Korean 1912-"), 9*kOneHour, 0, millis1912, 1, DateTimeRule::STANDARD_TIME);

    UErrorCode status = U_ZERO_ERROR;

    RuleBasedTimeZone* dangiCalZoneAstroCalc = new RuleBasedTimeZone(UNICODE_STRING_SIMPLE("KOREA_ZONE"), initialTimeZone); // adopts initialTimeZone

    dangiCalZoneAstroCalc->addTransitionRule(rule1897, status); // adopts rule1897

    dangiCalZoneAstroCalc->addTransitionRule(rule1898to1911, status);

    dangiCalZoneAstroCalc->addTransitionRule(ruleFrom1912, status);

    dangiCalZoneAstroCalc->complete(status);

    if (U_SUCCESS(status)) {

        gDangiCalendarZoneAstroCalc = dangiCalZoneAstroCalc;

    } else {

        delete dangiCalZoneAstroCalc;

        gDangiCalendarZoneAstroCalc = NULL;

    }

    ucln_i18n_registerCleanup(UCLN_I18N_DANGI_CALENDAR, calendar_dangi_cleanup);

}

const TimeZone* DangiCalendar::getDangiCalZoneAstroCalc(void) const {

    umtx_initOnce(gDangiCalendarInitOnce, &initDangiCalZoneAstroCalc);

    return gDangiCalendarZoneAstroCalc;

}

UOBJECT_DEFINE_RTTI_IMPLEMENTATION(DangiCalendar)

U_NAMESPACE_END

#endif