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

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

/*

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

* Copyright (C) 2003-2009,2012,2016 International Business Machines Corporation and

* others. All Rights Reserved.

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

*

* File JAPANCAL.CPP

*

* Modification History:

*  05/16/2003    srl     copied from buddhcal.cpp

*

*/

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING

#if U_PLATFORM_HAS_WINUWP_API == 0

#include <stdlib.h> // getenv() is not available in UWP env

#else

#ifndef WIN32_LEAN_AND_MEAN

#   define WIN32_LEAN_AND_MEAN

#endif

#   define VC_EXTRALEAN

#   define NOUSER

#   define NOSERVICE

#   define NOIME

#   define NOMCX

#include <windows.h>

#endif

#include "cmemory.h"

#include "erarules.h"

#include "japancal.h"

#include "unicode/gregocal.h"

#include "umutex.h"

#include "uassert.h"

#include "ucln_in.h"

#include "cstring.h"

static icu::EraRules * gJapaneseEraRules = nullptr;

static icu::UInitOnce gJapaneseEraRulesInitOnce {};

static int32_t gCurrentEra = 0;

U_CDECL_BEGIN

static UBool japanese_calendar_cleanup() {

    if (gJapaneseEraRules) {

        delete gJapaneseEraRules;

        gJapaneseEraRules = nullptr;

    }

    gCurrentEra = 0;

    gJapaneseEraRulesInitOnce.reset();

    return true;

}

U_CDECL_END

U_NAMESPACE_BEGIN

UOBJECT_DEFINE_RTTI_IMPLEMENTATION(JapaneseCalendar)

static const int32_t kGregorianEpoch = 1970;    // used as the default value of EXTENDED_YEAR

static const char* TENTATIVE_ERA_VAR_NAME = "ICU_ENABLE_TENTATIVE_ERA";

// Export the following for use by test code.

UBool JapaneseCalendar::enableTentativeEra() {

    // Although start date of next Japanese era is planned ahead, a name of

    // new era might not be available. This implementation allows tester to

    // check a new era without era names by settings below (in priority order).

    // By default, such tentative era is disabled.

    // 1. Environment variable ICU_ENABLE_TENTATIVE_ERA=true or false

    UBool includeTentativeEra = false;

#if U_PLATFORM_HAS_WINUWP_API == 1

    // UWP doesn't allow access to getenv(), but we can call GetEnvironmentVariableW to do the same thing.

    char16_t varName[26] = {};

    u_charsToUChars(TENTATIVE_ERA_VAR_NAME, varName, static_cast<int32_t>(uprv_strlen(TENTATIVE_ERA_VAR_NAME)));

    WCHAR varValue[5] = {};

    DWORD ret = GetEnvironmentVariableW(reinterpret_cast<WCHAR*>(varName), varValue, UPRV_LENGTHOF(varValue));

    if ((ret == 4) && (_wcsicmp(varValue, L"true") == 0)) {

        includeTentativeEra = true;

    }

#else

    char *envVarVal = getenv(TENTATIVE_ERA_VAR_NAME);

    if (envVarVal != nullptr && uprv_stricmp(envVarVal, "true") == 0) {

        includeTentativeEra = true;

    }

#endif

    return includeTentativeEra;

}

// Initialize global Japanese era data

static void U_CALLCONV initializeEras(UErrorCode &status) {

    gJapaneseEraRules = EraRules::createInstance("japanese", JapaneseCalendar::enableTentativeEra(), status);

    if (U_FAILURE(status)) {

        return;

    }

    gCurrentEra = gJapaneseEraRules->getCurrentEraIndex();

}

static void init(UErrorCode &status) {

    umtx_initOnce(gJapaneseEraRulesInitOnce, &initializeEras, status);

    ucln_i18n_registerCleanup(UCLN_I18N_JAPANESE_CALENDAR, japanese_calendar_cleanup);

}

/* Some platforms don't like to export constants, like old Palm OS and some z/OS configurations. */

uint32_t JapaneseCalendar::getCurrentEra() {

    return gCurrentEra;

}

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

:   GregorianCalendar(aLocale, success)

{

    init(success);

}

JapaneseCalendar::~JapaneseCalendar()

{

}

JapaneseCalendar::JapaneseCalendar(const JapaneseCalendar& source)

: GregorianCalendar(source)

{

    UErrorCode status = U_ZERO_ERROR;

    init(status);

    U_ASSERT(U_SUCCESS(status));

}

JapaneseCalendar* JapaneseCalendar::clone() const

{

    return new JapaneseCalendar(*this);

}

const char *JapaneseCalendar::getType() const

{

    return "japanese";

}

int32_t JapaneseCalendar::getDefaultMonthInYear(int32_t eyear, UErrorCode& status) 

{

    if (U_FAILURE(status)) {

      return 0;

    }

    int32_t era = internalGetEra();

    // TODO do we assume we can trust 'era'?  What if it is denormalized?

    int32_t month = 0;

    // Find out if we are at the edge of an era

    int32_t eraStart[3] = { 0,0,0 };

    gJapaneseEraRules->getStartDate(era, eraStart, status);

    if (U_FAILURE(status)) {

        return 0;

    }

    if(eyear == eraStart[0]) {

        // Yes, we're in the first year of this era.

        return eraStart[1]  // month

                -1;         // return 0-based month

    }

    return month;

}

int32_t JapaneseCalendar::getDefaultDayInMonth(int32_t eyear, int32_t month, UErrorCode& status) 

{

    if (U_FAILURE(status)) {

        return 0;

    }

    int32_t era = internalGetEra();

    int32_t day = 1;

    int32_t eraStart[3] = { 0,0,0 };

    gJapaneseEraRules->getStartDate(era, eraStart, status);

    if (U_FAILURE(status)) {

        return 0;

    }

    if (eyear == eraStart[0] && (month == eraStart[1] - 1)) {

        return eraStart[2];

    }

    return day;

}

int32_t JapaneseCalendar::internalGetEra() const

{

    return internalGet(UCAL_ERA, gCurrentEra);

}

int32_t JapaneseCalendar::handleGetExtendedYear(UErrorCode& status)

{

    if (U_FAILURE(status)) {

        return 0;

    }

    // EXTENDED_YEAR in JapaneseCalendar is a Gregorian year

    // The default value of EXTENDED_YEAR is 1970 (Showa 45)

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

        newerField(UCAL_EXTENDED_YEAR, UCAL_ERA) == UCAL_EXTENDED_YEAR) {

        return internalGet(UCAL_EXTENDED_YEAR, kGregorianEpoch);

    }

    int32_t eraStartYear = gJapaneseEraRules->getStartYear(internalGet(UCAL_ERA, gCurrentEra), status);

    if (U_FAILURE(status)) {

        return 0;

    }

    // extended year is a gregorian year, where 1 = 1AD,  0 = 1BC, -1 = 2BC, etc

    int32_t year = internalGet(UCAL_YEAR, 1);   // pin to minimum of year 1 (first year)

    // add gregorian starting year, subtract one because year starts at 1

    if (uprv_add32_overflow(year, eraStartYear - 1,  &year)) {

        status = U_ILLEGAL_ARGUMENT_ERROR;

        return 0;

    }

    return year;

}

void JapaneseCalendar::handleComputeFields(int32_t julianDay, UErrorCode& status)

{

    //Calendar::timeToFields(theTime, quick, status);

    GregorianCalendar::handleComputeFields(julianDay, status);

    int32_t year = internalGet(UCAL_EXTENDED_YEAR); // Gregorian year

    int32_t eraIdx = gJapaneseEraRules->getEraIndex(year, internalGetMonth(status) + 1, internalGet(UCAL_DAY_OF_MONTH), status);

    int32_t startYear = gJapaneseEraRules->getStartYear(eraIdx, status) - 1;

    if (U_FAILURE(status)) {

        return;

    }

    if (uprv_add32_overflow(year, -startYear,  &year)) {

        status = U_ILLEGAL_ARGUMENT_ERROR;

        return;

    }

    internalSet(UCAL_ERA, eraIdx);

    internalSet(UCAL_YEAR, year);

}

/*

Disable pivoting 

*/

UBool JapaneseCalendar::haveDefaultCentury() const

{

    return false;

}

UDate JapaneseCalendar::defaultCenturyStart() const

{

    return 0;// WRONG

}

int32_t JapaneseCalendar::defaultCenturyStartYear() const

{

    return 0;

}

int32_t JapaneseCalendar::handleGetLimit(UCalendarDateFields field, ELimitType limitType) const

{

    switch(field) {

    case UCAL_ERA:

        if (limitType == UCAL_LIMIT_MINIMUM || limitType == UCAL_LIMIT_GREATEST_MINIMUM) {

            return 0;

        }

        return gJapaneseEraRules->getNumberOfEras() - 1; // max known era, not gCurrentEra

    case UCAL_YEAR:

        {

            switch (limitType) {

            case UCAL_LIMIT_MINIMUM:

            case UCAL_LIMIT_GREATEST_MINIMUM:

                return 1;

            case UCAL_LIMIT_LEAST_MAXIMUM:

                return 1;

            case  UCAL_LIMIT_COUNT: //added to avoid warning

            case UCAL_LIMIT_MAXIMUM:

            {

                UErrorCode status = U_ZERO_ERROR;

                int32_t eraStartYear = gJapaneseEraRules->getStartYear(gCurrentEra, status);

                U_ASSERT(U_SUCCESS(status));

                return GregorianCalendar::handleGetLimit(UCAL_YEAR, UCAL_LIMIT_MAXIMUM) - eraStartYear;

            }

            default:

                return 1;    // Error condition, invalid limitType

            }

        }

    default:

        return GregorianCalendar::handleGetLimit(field,limitType);

    }

}

int32_t JapaneseCalendar::getActualMaximum(UCalendarDateFields field, UErrorCode& status) const {

    if (field != UCAL_YEAR) {

        return GregorianCalendar::getActualMaximum(field, status);

    }

    int32_t era = get(UCAL_ERA, status);

    if (U_FAILURE(status)) {

        return 0; // error case... any value

    }

    if (era == gJapaneseEraRules->getNumberOfEras() - 1) { // max known era, not gCurrentEra

        // TODO: Investigate what value should be used here - revisit after 4.0.

        return handleGetLimit(UCAL_YEAR, UCAL_LIMIT_MAXIMUM);

    }

    int32_t nextEraStart[3] = { 0,0,0 };

    gJapaneseEraRules->getStartDate(era + 1, nextEraStart, status);

    int32_t nextEraYear = nextEraStart[0];

    int32_t nextEraMonth = nextEraStart[1]; // 1-base

    int32_t nextEraDate = nextEraStart[2];

    int32_t eraStartYear = gJapaneseEraRules->getStartYear(era, status);

    int32_t maxYear = nextEraYear - eraStartYear + 1;   // 1-base

    if (nextEraMonth == 1 && nextEraDate == 1) {

        // Subtract 1, because the next era starts at Jan 1

        maxYear--;

    }

    return maxYear;

}

U_NAMESPACE_END

#endif