/*
*******************************************************************************
* Copyright (C) 2003-2004, 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

#include "japancal.h"
#include "unicode/gregocal.h"
#include "mutex.h"
#include "uassert.h"

//#define U_DEBUG_JCAL

#ifdef U_DEBUG_JCAL
#include <stdio.h>
#endif

U_NAMESPACE_BEGIN

const char JapaneseCalendar::fgClassID = 0; // Value is irrelevant

//  Gregorian date of each emperor's ascension
//  Years are AD, months are 1-based.
static const struct { 
   int16_t year;
   int8_t  month;
   int8_t  day;
} kEraInfo[] =  {
      //  Year  Month Day
      {   645,    6, 19 },   // Taika   0
      {   650,    2, 15 },   // Hakuchi 1
      {   672,    1,  1 },   // Hakuho  2
      {   686,    7, 20 },   // Shucho  3
      {   701,    3, 21 },   // Taiho   4
      {   704,    5, 10 },   // Keiun   5
      {   708,    1, 11 },   // Wado    6
      {   715,    9,  2 },   // Reiki   7
      {   717,   11, 17 },   // Yoro    8
      {   724,    2,  4 },   // Jinki   9
      {   729,    8,  5 },   // Tempyo  10
      {   749,    4, 14 },   // Tempyo-kampo 11
      {   749,    7,  2 },   // Tempyo-shoho 12
      {   757,    8, 18 },   // Tempyo-hoji  13
      {   765,    1,  7 },   // Tempho-jingo 14
      {   767,    8, 16 },   // Jingo-keiun  15
      {   770,   10,  1 },   // Hoki         16
      {   781,    1,  1 },   // Ten-o        17
      {   782,    8, 19 },   // Enryaku      18
      {   806,    5, 18 },   // Daido        19
      {   810,    9, 19 },   // Konin        20
      {   824,    1,  5 },   // Tencho
      {   834,    1,  3 },   // Showa
      {   848,    6, 13 },   // Kajo
      {   851,    4, 28 },   // Ninju
      {   854,   11, 30 },   // Saiko
      {   857,    2, 21 },   // Tennan
      {   859,    4, 15 },   // Jogan
      {   877,    4, 16 },   // Genkei
      {   885,    2, 21 },   // Ninna
      {   889,    4, 27 },   // Kampyo       30
      {   898,    4, 26 },   // Shotai
      {   901,    7, 15 },   // Engi
      {   923,    4, 11 },   // Encho
      {   931,    4, 26 },   // Shohei
      {   938,    5, 22 },   // Tengyo
      {   947,    4, 22 },   // Tenryaku
      {   957,   10, 27 },   // Tentoku
      {   961,    2, 16 },   // Owa
      {   964,    7, 10 },   // Koho
      {   968,    8, 13 },   // Anna        40
      {   970,    3, 25 },   // Tenroku
      {   973,   12, 20 },   // Ten-en
      {   976,    7, 13 },   // Jogen
      {   978,   11, 29 },   // Tengen
      {   983,    4, 15 },   // Eikan
      {   985,    4, 27 },   // Kanna
      {   987,    4,  5 },   // Ei-en
      {   989,    8,  8 },   // Eiso
      {   990,   11,  7 },   // Shoryaku
      {   995,    2, 22 },   // Chotoku      50
      {   999,    1, 13 },   // Choho
      {  1004,    7, 20 },   // Kanko
      {  1012,   12, 25 },   // Chowa
      {  1017,    4, 23 },   // Kannin
      {  1021,    2,  2 },   // Jian
      {  1024,    7, 13 },   // Manju
      {  1028,    7, 25 },   // Chogen
      {  1037,    4, 21 },   // Choryaku
      {  1040,   11, 10 },   // Chokyu
      {  1044,   11, 24 },   // Kantoku      60
      {  1046,    4, 14 },   // Eisho
      {  1053,    1, 11 },   // Tengi
      {  1058,    8, 29 },   // Kohei
      {  1065,    8,  2 },   // Jiryaku
      {  1069,    4, 13 },   // Enkyu
      {  1074,    8, 23 },   // Shoho
      {  1077,   11, 17 },   // Shoryaku
      {  1081,    2, 10 },   // Eiho
      {  1084,    2,  7 },   // Otoku
      {  1087,    4,  7 },   // Kanji       70
      {  1094,   12, 15 },   // Kaho
      {  1096,   12, 17 },   // Eicho
      {  1097,   11, 21 },   // Shotoku
      {  1099,    8, 28 },   // Kowa
      {  1104,    2, 10 },   // Choji
      {  1106,    4,  9 },   // Kasho
      {  1108,    8,  3 },   // Tennin
      {  1110,    7, 13 },   // Ten-ei
      {  1113,    7, 13 },   // Eikyu
      {  1118,    4,  3 },   // Gen-ei      80
      {  1120,    4, 10 },   // Hoan
      {  1124,    4,  3 },   // Tenji
      {  1126,    1, 22 },   // Daiji
      {  1131,    1, 29 },   // Tensho
      {  1132,    8, 11 },   // Chosho
      {  1135,    4, 27 },   // Hoen
      {  1141,    7, 10 },   // Eiji
      {  1142,    4, 28 },   // Koji
      {  1144,    2, 23 },   // Tenyo
      {  1145,    7, 22 },   // Kyuan      90
      {  1151,    1, 26 },   // Ninpei
      {  1154,   10, 28 },   // Kyuju
      {  1156,    4, 27 },   // Hogen
      {  1159,    4, 20 },   // Heiji
      {  1160,    1, 10 },   // Eiryaku
      {  1161,    9,  4 },   // Oho
      {  1163,    3, 29 },   // Chokan
      {  1165,    6,  5 },   // Eiman
      {  1166,    8, 27 },   // Nin-an
      {  1169,    4,  8 },   // Kao       100
      {  1171,    4, 21 },   // Shoan
      {  1175,    7, 28 },   // Angen
      {  1177,    8,  4 },   // Jisho
      {  1181,    7, 14 },   // Yowa
      {  1182,    5, 27 },   // Juei
      {  1184,    4, 16 },   // Genryuku
      {  1185,    8, 14 },   // Bunji
      {  1190,    4, 11 },   // Kenkyu
      {  1199,    4, 27 },   // Shoji
      {  1201,    2, 13 },   // Kennin     110
      {  1204,    2, 20 },   // Genkyu
      {  1206,    4, 27 },   // Ken-ei
      {  1207,   10, 25 },   // Shogen
      {  1211,    3,  9 },   // Kenryaku
      {  1213,   12,  6 },   // Kenpo
      {  1219,    4, 12 },   // Shokyu
      {  1222,    4, 13 },   // Joo
      {  1224,   11, 20 },   // Gennin
      {  1225,    4, 20 },   // Karoku
      {  1227,   12, 10 },   // Antei      120
      {  1229,    3,  5 },   // Kanki
      {  1232,    4,  2 },   // Joei
      {  1233,    4, 15 },   // Tempuku
      {  1234,   11,  5 },   // Bunryaku
      {  1235,    9, 19 },   // Katei
      {  1238,   11, 23 },   // Ryakunin
      {  1239,    2,  7 },   // En-o
      {  1240,    7, 16 },   // Ninji
      {  1243,    2, 26 },   // Kangen
      {  1247,    2, 28 },   // Hoji      130
      {  1249,    3, 18 },   // Kencho
      {  1256,   10,  5 },   // Kogen
      {  1257,    3, 14 },   // Shoka
      {  1259,    3, 26 },   // Shogen
      {  1260,    4, 13 },   // Bun-o
      {  1261,    2, 20 },   // Kocho
      {  1264,    2, 28 },   // Bun-ei
      {  1275,    4, 25 },   // Kenji
      {  1278,    2, 29 },   // Koan
      {  1288,    4, 28 },   // Shoo      140
      {  1293,    8, 55 },   // Einin
      {  1299,    4, 25 },   // Shoan
      {  1302,   11, 21 },   // Kengen
      {  1303,    8,  5 },   // Kagen
      {  1306,   12, 14 },   // Tokuji
      {  1308,   10,  9 },   // Enkei
      {  1311,    4, 28 },   // Ocho
      {  1312,    3, 20 },   // Showa
      {  1317,    2,  3 },   // Bunpo
      {  1319,    4, 28 },   // Geno      150
      {  1321,    2, 23 },   // Genkyo
      {  1324,   12,  9 },   // Shochu
      {  1326,    4, 26 },   // Kareki
      {  1329,    8, 29 },   // Gentoku
      {  1331,    8,  9 },   // Genko
      {  1334,    1, 29 },   // Kemmu
      {  1336,    2, 29 },   // Engen
      {  1340,    4, 28 },   // Kokoku
      {  1346,   12,  8 },   // Shohei
      {  1370,    7, 24 },   // Kentoku       160
      {  1372,    4,  1 },   // Bunch\u0169
      {  1375,    5, 27 },   // Tenju
      {  1379,    3, 22 },   // Koryaku
      {  1381,    2, 10 },   // Kowa
      {  1384,    4, 28 },   // Gench\u0169
      {  1384,    2, 27 },   // Meitoku
      {  1387,    8, 23 },   // Kakei
      {  1389,    2,  9 },   // Koo
      {  1390,    3, 26 },   // Meitoku
      {  1394,    7,  5 },   // Oei           170
      {  1428,    4, 27 },   // Shocho
      {  1429,    9,  5 },   // Eikyo
      {  1441,    2, 17 },   // Kakitsu
      {  1444,    2,  5 },   // Bun-an
      {  1449,    7, 28 },   // Hotoku
      {  1452,    7, 25 },   // Kyotoku
      {  1455,    7, 25 },   // Kosho
      {  1457,    9, 28 },   // Choroku
      {  1460,   12, 21 },   // Kansho
      {  1466,    2, 28 },   // Bunsho        180
      {  1467,    3,  3 },   // Onin
      {  1469,    4, 28 },   // Bunmei
      {  1487,    7, 29 },   // Chokyo
      {  1489,    8, 21 },   // Entoku
      {  1492,    7, 19 },   // Meio
      {  1501,    2, 29 },   // Bunki
      {  1504,    2, 30 },   // Eisho
      {  1521,    8, 23 },   // Taiei
      {  1528,    8, 20 },   // Kyoroku
      {  1532,    7, 29 },   // Tenmon       190
      {  1555,   10, 23 },   // Koji
      {  1558,    2, 28 },   // Eiroku
      {  1570,    4, 23 },   // Genki
      {  1573,    7, 28 },   // Tensho
      {  1592,   12,  8 },   // Bunroku
      {  1596,   10, 27 },   // Keicho
      {  1615,    7, 13 },   // Genwa
      {  1624,    2, 30 },   // Kan-ei
      {  1644,   12, 16 },   // Shoho
      {  1648,    2, 15 },   // Keian       200
      {  1652,    9, 18 },   // Shoo
      {  1655,    4, 13 },   // Meiryaku
      {  1658,    7, 23 },   // Manji
      {  1661,    4, 25 },   // Kanbun
      {  1673,    9, 21 },   // Enpo
      {  1681,    9, 29 },   // Tenwa
      {  1684,    2, 21 },   // Jokyo
      {  1688,    9, 30 },   // Genroku
      {  1704,    3, 13 },   // Hoei
      {  1711,    4, 25 },   // Shotoku      210
      {  1716,    6, 22 },   // Kyoho
      {  1736,    4, 28 },   // Genbun
      {  1741,    2, 27 },   // Kanpo
      {  1744,    2, 21 },   // Enkyo
      {  1748,    7, 12 },   // Kan-en
      {  1751,   10, 27 },   // Horyaku
      {  1764,    6,  2 },   // Meiwa
      {  1772,   11, 16 },   // An-ei
      {  1781,    4,  2 },   // Tenmei
      {  1789,    1, 25 },   // Kansei      220
      {  1801,    2,  5 },   // Kyowa
      {  1804,    2, 11 },   // Bunka
      {  1818,    4, 22 },   // Bunsei
      {  1830,   12, 10 },   // Tenpo
      {  1844,   12,  2 },   // Koka
      {  1848,    2, 28 },   // Kaei
      {  1854,   11, 27 },   // Ansei
      {  1860,    3, 18 },   // Man-en
      {  1861,    2, 19 },   // Bunkyu
      {  1864,    2, 20 },   // Genji        230
      {  1865,    4,  7 },   // Keio     231
      {  1868,    9,  8 },   // Meiji    232
      {  1912,    7, 30 },   // Taisho   233
      {  1926,   12, 25 },   // Showa    234
      {  1989,    1,  8 }   // Heisei    235
     };

#define kEraCount (sizeof(kEraInfo)/sizeof(kEraInfo[0]))

const uint32_t JapaneseCalendar::kCurrentEra = (kEraCount-1);

JapaneseCalendar::JapaneseCalendar(const Locale& aLocale, UErrorCode& success)
  :   GregorianCalendar(aLocale, success)
{
    setTimeInMillis(getNow(), success); // Call this again now that the vtable is set up properly.
}

JapaneseCalendar::~JapaneseCalendar()
{
}

JapaneseCalendar::JapaneseCalendar(const JapaneseCalendar& source)
  : GregorianCalendar(source)
{
}

JapaneseCalendar& JapaneseCalendar::operator= ( const JapaneseCalendar& right)
{
  GregorianCalendar::operator=(right);
  return *this;
}

Calendar* JapaneseCalendar::clone(void) const
{
  return new JapaneseCalendar(*this);
}

const char *JapaneseCalendar::getType() const
{
  return "japanese";
}

int32_t JapaneseCalendar::getDefaultMonthInYear() 
{
  UErrorCode status  = U_ZERO_ERROR;
  int32_t era = internalGetEra();
  computeFields(status); // slow
  int32_t year = getGregorianYear();
  // TODO do we assume we can trust 'era'?  What if it is denormalized?

  int32_t month = GregorianCalendar::getDefaultMonthInYear();

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

  if(year == kEraInfo[era].year) {
    // Yes, we're in the first year of this era.
    return kEraInfo[era].month-1;
  }

  return month;
}

int32_t JapaneseCalendar::getDefaultDayInMonth(int32_t month) 
{
  UErrorCode status  = U_ZERO_ERROR;
  int32_t era = internalGetEra();
  computeFields(status); // slow
  int32_t year = getGregorianYear();
  int32_t day = GregorianCalendar::getDefaultDayInMonth(month);
  
  if(year == kEraInfo[era].year) {
    if(month == (kEraInfo[era].month-1)) {
      return kEraInfo[era].day;
    }
  }

  return day;
}


int32_t JapaneseCalendar::internalGetEra() const
{
  return internalGet(UCAL_ERA, kCurrentEra);
}

int32_t JapaneseCalendar::handleGetExtendedYear()
{
  int32_t year;

  if (newerField(UCAL_EXTENDED_YEAR, UCAL_YEAR) == UCAL_EXTENDED_YEAR &&
      newerField(UCAL_EXTENDED_YEAR, UCAL_ERA) == UCAL_EXTENDED_YEAR) {
    year = internalGet(UCAL_EXTENDED_YEAR, 1);
  } else {
    // Subtract one because year starts at 1
    year = internalGet(UCAL_YEAR) + kEraInfo[internalGet(UCAL_ERA)].year - 1;
  }
  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 low = 0;
  
  // Short circuit for recent years.  Most modern computations will
  // occur in the current era and won't require the binary search.
  // Note that if the year is == the current era year, then we use
  // the binary search to handle the month/dom comparison.
#ifdef U_DEBUG_JCAL
  fprintf(stderr, "==  %d:%d \n", era, year);
#endif

  if (year > kEraInfo[kCurrentEra].year) {
    low = kCurrentEra;
#ifdef U_DEBUG_JCAL
    fprintf(stderr, " low=%d (special)\n", low);
#endif
  } else {
    // Binary search
    int32_t high = kEraCount;
    
#ifdef U_DEBUG_JCAL
    fprintf(stderr, " high=%d\n", high);
#endif
    while (low < high - 1) {
      int32_t i = (low + high) / 2;
      int32_t diff = year - kEraInfo[i].year;

#ifdef U_DEBUG_JCAL
      fprintf(stderr, "  d=%d   low=%d, high=%d. Considering %d:M%d D%d Y%d. { we are ?:M%d D%d Y%d }\n",
              diff,low, high, i, kEraInfo[i].month-1, kEraInfo[i].day,  kEraInfo[i].year, internalGet(UCAL_MONTH), internalGet(UCAL_DATE),year);
#endif
      
      // If years are the same, then compare the months, and if those
      // are the same, compare days of month.  In the ERAS array
      // months are 1-based for easier maintenance.
      if (diff == 0) {
        diff = internalGet(UCAL_MONTH) - (kEraInfo[i].month - 1);
#ifdef U_DEBUG_JCAL
              fprintf(stderr, "diff now %d (M)  = %d - %d - 1\n", diff, internalGet(UCAL_MONTH), kEraInfo[i].month);
#endif
        if (diff == 0) {
          diff = internalGet(UCAL_DATE) - kEraInfo[i].day;
#ifdef U_DEBUG_JCAL
          fprintf(stderr, "diff now %d (D)\n", diff);
#endif
        }
      }
      if (diff >= 0) {
        low = i;
      } else {
        high = i;
      }
#ifdef U_DEBUG_JCAL
      fprintf(stderr, ". low=%d, high=%d, i=%d, diff=%d.. %d\n", low, high, i, diff, year);
#endif

    }
  }

#ifdef U_DEBUG_JCAL
  fprintf(stderr, "  low[era]=%d,.. %d\n", low, year);
#endif
  // Now we've found the last era that starts before this date, so
  // adjust the year to count from the start of that era.  Note that
  // all dates before the first era will fall into the first era by
  // the algorithm.
  
  internalSet(UCAL_ERA, low);
  internalSet(UCAL_YEAR, year - kEraInfo[low].year + 1);
#ifdef U_DEBUG_JCAL
  fprintf(stderr, "  Set ERA=%d, year=%d\n", low, year-kEraInfo[low].year+1);
#endif

}

/*
  Disable pivoting 
*/
UBool JapaneseCalendar::haveDefaultCentury() const
{
  return FALSE;
}

UDate JapaneseCalendar::defaultCenturyStart() const
{
  return 0;// WRONG
}

int32_t JapaneseCalendar::defaultCenturyStartYear() const
{
  return 0;
}

static int32_t gJapanCalendarLimits[2][4] = {
  //    Minimum  Greatest min      Least max   Greatest max
  {        0,        0, JapaneseCalendar::kCurrentEra, JapaneseCalendar::kCurrentEra }, // ERA
  {        1,        1,           0,           0 }, // YEAR least-max/greatest-max computed at runtime
};

static UBool gJapanYearLimitsKnown = FALSE;

int32_t JapaneseCalendar::handleGetLimit(UCalendarDateFields field, ELimitType limitType) const
{
  switch(field) {
  case UCAL_YEAR:
    {
      UBool needCalc = FALSE;
      { 
        Mutex m;
        needCalc = (gJapanYearLimitsKnown == FALSE);
      }
      if(needCalc) {
        int32_t min = kEraInfo[1].year - kEraInfo[0].year;
        int32_t max = min;
        for (uint32_t i=2; i<kEraCount; i++) { // counting by year, not field (3's)
          int32_t d = kEraInfo[i].year - kEraInfo[i-1].year;
          U_ASSERT(d >= 0);
          if (d < min) {
            min = d;
          }
          if (d > max) {
            max = d;
          }
        }
        U_ASSERT(min >= 0 && max > min);
        { 
          Mutex m;
          if(gJapanYearLimitsKnown==FALSE) {
            gJapanCalendarLimits[field][UCAL_LIMIT_LEAST_MAXIMUM] = ++min; // 1-based
            gJapanCalendarLimits[field][UCAL_LIMIT_MAXIMUM] = ++max; // 1-based
            gJapanYearLimitsKnown = TRUE;
          }
        }
      }
      return gJapanCalendarLimits[field][limitType];
    }

  case UCAL_ERA:
    return gJapanCalendarLimits[field][limitType];

  case UCAL_EXTENDED_YEAR:  // extended year limits
    switch(limitType) {
    case UCAL_LIMIT_GREATEST_MINIMUM:
    case UCAL_LIMIT_MINIMUM:
      return kEraInfo[0].year;  /* minimum is 1st era year */

    case UCAL_LIMIT_LEAST_MAXIMUM:
    case UCAL_LIMIT_MAXIMUM:
      /* use Gregorian calendar max */
    default:
      return GregorianCalendar::handleGetLimit(field,limitType);
    }
    break;

  default:
    return GregorianCalendar::handleGetLimit(field,limitType);
  }
}


U_NAMESPACE_END

#endif