/*

 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 *

 *  * Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 *

 *  * Neither the name of JSR-310 nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

package java.time.chrono;

import java.io.Serializable;

import java.time.Clock;

import java.time.DateTimeException;

import java.time.Instant;

import java.time.LocalDate;

import java.time.temporal.ChronoField;

import java.time.temporal.TemporalAccessor;

import java.time.temporal.ValueRange;

import java.time.Year;

import java.time.ZoneId;

import java.util.Arrays;

import java.util.Calendar;

import java.util.List;

import java.util.Locale;

import sun.util.calendar.CalendarSystem;

import sun.util.calendar.LocalGregorianCalendar;

/**

 * The Japanese Imperial calendar system.

 * <p>

 * This chronology defines the rules of the Japanese Imperial calendar system.

 * This calendar system is primarily used in Japan.

 * The Japanese Imperial calendar system is the same as the ISO calendar system

 * apart from the era-based year numbering.

 * <p>

 * Only Meiji (1865-04-07 - 1868-09-07) and later eras are supported.

 * Older eras are handled as an unknown era where the year-of-era is the ISO year.

 *

 * <h3>Specification for implementors</h3>

 * This class is immutable and thread-safe.

 *

 * @since 1.8

 */

public final class JapaneseChronology extends Chronology implements Serializable {

    // TODO: definition for unknown era may break requirement that year-of-era >= 1

    static final LocalGregorianCalendar JCAL =

        (LocalGregorianCalendar) CalendarSystem.forName("japanese");

    // Locale for creating a JapaneseImpericalCalendar.

    static final Locale LOCALE = Locale.forLanguageTag("ja-JP-u-ca-japanese");

    /**

     * Singleton instance for Japanese chronology.

     */

    public static final JapaneseChronology INSTANCE = new JapaneseChronology();

    /**

     * The singleton instance for the before Meiji era ( - 1868-09-07)

     * which has the value -999.

     */

    public static final Era ERA_SEIREKI = JapaneseEra.SEIREKI;

    /**

     * The singleton instance for the Meiji era (1868-09-08 - 1912-07-29)

     * which has the value -1.

     */

    public static final Era ERA_MEIJI = JapaneseEra.MEIJI;

    /**

     * The singleton instance for the Taisho era (1912-07-30 - 1926-12-24)

     * which has the value 0.

     */

    public static final Era ERA_TAISHO = JapaneseEra.TAISHO;

    /**

     * The singleton instance for the Showa era (1926-12-25 - 1989-01-07)

     * which has the value 1.

     */

    public static final Era ERA_SHOWA = JapaneseEra.SHOWA;

    /**

     * The singleton instance for the Heisei era (1989-01-08 - current)

     * which has the value 2.

     */

    public static final Era ERA_HEISEI = JapaneseEra.HEISEI;

    /**

     * Serialization version.

     */

    private static final long serialVersionUID = 459996390165777884L;

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

    /**

     * Restricted constructor.

     */

    private JapaneseChronology() {

    }

    /**

     * Resolve singleton.

     *

     * @return the singleton instance, not null

     */

    private Object readResolve() {

        return INSTANCE;

    }

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

    /**

     * Gets the ID of the chronology - 'Japanese'.

     * <p>

     * The ID uniquely identifies the {@code Chronology}.

     * It can be used to lookup the {@code Chronology} using {@link #of(String)}.

     *

     * @return the chronology ID - 'Japanese'

     * @see #getCalendarType()

     */

    @Override

    public String getId() {

        return "Japanese";

    }

    /**

     * Gets the calendar type of the underlying calendar system - 'japanese'.

     * <p>

     * The calendar type is an identifier defined by the

     * <em>Unicode Locale Data Markup Language (LDML)</em> specification.

     * It can be used to lookup the {@code Chronology} using {@link #of(String)}.

     * It can also be used as part of a locale, accessible via

     * {@link Locale#getUnicodeLocaleType(String)} with the key 'ca'.

     *

     * @return the calendar system type - 'japanese'

     * @see #getId()

     */

    @Override

    public String getCalendarType() {

        return "japanese";

    }

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

    @Override

    public JapaneseDate date(Era era, int yearOfEra, int month, int dayOfMonth) {

        if (era instanceof JapaneseEra == false) {

            throw new DateTimeException("Era must be JapaneseEra");

        }

        return JapaneseDate.of((JapaneseEra) era, yearOfEra, month, dayOfMonth);

    }

    @Override

    public JapaneseDate date(int prolepticYear, int month, int dayOfMonth) {

        return new JapaneseDate(LocalDate.of(prolepticYear, month, dayOfMonth));

    }

    @Override

    public JapaneseDate dateYearDay(int prolepticYear, int dayOfYear) {

        LocalDate date = LocalDate.ofYearDay(prolepticYear, dayOfYear);

        return date(prolepticYear, date.getMonthValue(), date.getDayOfMonth());

    }

    @Override

    public JapaneseDate date(TemporalAccessor temporal) {

        if (temporal instanceof JapaneseDate) {

            return (JapaneseDate) temporal;

        }

        return new JapaneseDate(LocalDate.from(temporal));

    }

    @Override

    public JapaneseDate dateYearDay(Era era, int yearOfEra, int dayOfYear) {

        return dateYearDay(prolepticYear(era, yearOfEra), dayOfYear);

    }

    @Override

    public JapaneseDate dateNow() {

        return dateNow(Clock.systemDefaultZone());

    }

    @Override

    public JapaneseDate dateNow(ZoneId zone) {

        return dateNow(Clock.system(zone));

    }

    @Override

    public JapaneseDate dateNow(Clock clock) {

        return date(LocalDate.now(clock));

    }

    @Override

    public ChronoLocalDateTime<JapaneseDate> localDateTime(TemporalAccessor temporal) {

        return (ChronoLocalDateTime<JapaneseDate>)super.localDateTime(temporal);

    }

    @Override

    public ChronoZonedDateTime<JapaneseDate> zonedDateTime(TemporalAccessor temporal) {

        return (ChronoZonedDateTime<JapaneseDate>)super.zonedDateTime(temporal);

    }

    @Override

    public ChronoZonedDateTime<JapaneseDate> zonedDateTime(Instant instant, ZoneId zone) {

        return (ChronoZonedDateTime<JapaneseDate>)super.zonedDateTime(instant, zone);

    }

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

    /**

     * Checks if the specified year is a leap year.

     * <p>

     * Japanese calendar leap years occur exactly in line with ISO leap years.

     * This method does not validate the year passed in, and only has a

     * well-defined result for years in the supported range.

     *

     * @param prolepticYear  the proleptic-year to check, not validated for range

     * @return true if the year is a leap year

     */

    @Override

    public boolean isLeapYear(long prolepticYear) {

        return IsoChronology.INSTANCE.isLeapYear(prolepticYear);

    }

    @Override

    public int prolepticYear(Era era, int yearOfEra) {

        if (era instanceof JapaneseEra == false) {

            throw new DateTimeException("Era must be JapaneseEra");

        }

        JapaneseEra jera = (JapaneseEra) era;

        int gregorianYear = jera.getPrivateEra().getSinceDate().getYear() + yearOfEra - 1;

        if (yearOfEra == 1) {

            return gregorianYear;

        }

        LocalGregorianCalendar.Date jdate = JCAL.newCalendarDate(null);

        jdate.setEra(jera.getPrivateEra()).setDate(yearOfEra, 1, 1);

        JCAL.normalize(jdate);

        if (jdate.getNormalizedYear() == gregorianYear) {

            return gregorianYear;

        }

        throw new DateTimeException("invalid yearOfEra value");

    }

    /**

     * Returns the calendar system era object from the given numeric value.

     *

     * See the description of each Era for the numeric values of:

     * {@link #ERA_HEISEI}, {@link #ERA_SHOWA},{@link #ERA_TAISHO},

     * {@link #ERA_MEIJI}), only Meiji and later eras are supported.

     * Prior to Meiji {@link #ERA_SEIREKI} is used.

     *

     * @param eraValue  the era value

     * @return the Japanese {@code Era} for the given numeric era value

     * @throws DateTimeException if {@code eraValue} is invalid

     */

    @Override

    public Era eraOf(int eraValue) {

        return JapaneseEra.of(eraValue);

    }

    @Override

    public List<Era> eras() {

        return Arrays.<Era>asList(JapaneseEra.values());

    }

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

    @Override

    public ValueRange range(ChronoField field) {

        switch (field) {

            case DAY_OF_MONTH:

            case DAY_OF_WEEK:

            case MICRO_OF_DAY:

            case MICRO_OF_SECOND:

            case HOUR_OF_DAY:

            case HOUR_OF_AMPM:

            case MINUTE_OF_DAY:

            case MINUTE_OF_HOUR:

            case SECOND_OF_DAY:

            case SECOND_OF_MINUTE:

            case MILLI_OF_DAY:

            case MILLI_OF_SECOND:

            case NANO_OF_DAY:

            case NANO_OF_SECOND:

            case CLOCK_HOUR_OF_DAY:

            case CLOCK_HOUR_OF_AMPM:

            case EPOCH_DAY:

            case EPOCH_MONTH:

                return field.range();

        }

        Calendar jcal = Calendar.getInstance(LOCALE);

        int fieldIndex;

        switch (field) {

            case ERA:

                return ValueRange.of(jcal.getMinimum(Calendar.ERA) - JapaneseEra.ERA_OFFSET,

                        jcal.getMaximum(Calendar.ERA) - JapaneseEra.ERA_OFFSET);

            case YEAR:

            case YEAR_OF_ERA:

                return ValueRange.of(Year.MIN_VALUE, jcal.getGreatestMinimum(Calendar.YEAR),

                        jcal.getLeastMaximum(Calendar.YEAR), Year.MAX_VALUE);

            case MONTH_OF_YEAR:

                return ValueRange.of(jcal.getMinimum(Calendar.MONTH) + 1, jcal.getGreatestMinimum(Calendar.MONTH) + 1,

                        jcal.getLeastMaximum(Calendar.MONTH) + 1, jcal.getMaximum(Calendar.MONTH) + 1);

            case DAY_OF_YEAR:

                fieldIndex = Calendar.DAY_OF_YEAR;

                break;

            default:

                 // TODO: review the remaining fields

                throw new UnsupportedOperationException("Unimplementable field: " + field);

        }

        return ValueRange.of(jcal.getMinimum(fieldIndex), jcal.getGreatestMinimum(fieldIndex),

                jcal.getLeastMaximum(fieldIndex), jcal.getMaximum(fieldIndex));

    }

}