/*

 * 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

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 */

/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Copyright (c) 2007-2012, 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;

import static java.time.LocalTime.HOURS_PER_DAY;

import static java.time.LocalTime.MICROS_PER_DAY;

import static java.time.LocalTime.MILLIS_PER_DAY;

import static java.time.LocalTime.MINUTES_PER_DAY;

import static java.time.LocalTime.NANOS_PER_DAY;

import static java.time.LocalTime.NANOS_PER_HOUR;

import static java.time.LocalTime.NANOS_PER_MINUTE;

import static java.time.LocalTime.NANOS_PER_SECOND;

import static java.time.LocalTime.SECONDS_PER_DAY;

import static java.time.temporal.ChronoField.NANO_OF_SECOND;

import java.io.DataInput;

import java.io.DataOutput;

import java.io.IOException;

import java.io.InvalidObjectException;

import java.io.Serializable;

import java.time.chrono.ChronoLocalDateTime;

import java.time.format.DateTimeFormatter;

import java.time.format.DateTimeParseException;

import java.time.temporal.ChronoField;

import java.time.temporal.ChronoUnit;

import java.time.temporal.Temporal;

import java.time.temporal.TemporalAccessor;

import java.time.temporal.TemporalAdjuster;

import java.time.temporal.TemporalAmount;

import java.time.temporal.TemporalField;

import java.time.temporal.TemporalQueries;

import java.time.temporal.TemporalQuery;

import java.time.temporal.TemporalUnit;

import java.time.temporal.UnsupportedTemporalTypeException;

import java.time.temporal.ValueRange;

import java.time.zone.ZoneRules;

import java.util.Objects;

/**

 * A date-time without a time-zone in the ISO-8601 calendar system,

 * such as {@code 2007-12-03T10:15:30}.

 * <p>

 * {@code LocalDateTime} is an immutable date-time object that represents a date-time,

 * often viewed as year-month-day-hour-minute-second. Other date and time fields,

 * such as day-of-year, day-of-week and week-of-year, can also be accessed.

 * Time is represented to nanosecond precision.

 * For example, the value "2nd October 2007 at 13:45.30.123456789" can be

 * stored in a {@code LocalDateTime}.

 * <p>

 * This class does not store or represent a time-zone.

 * Instead, it is a description of the date, as used for birthdays, combined with

 * the local time as seen on a wall clock.

 * It cannot represent an instant on the time-line without additional information

 * such as an offset or time-zone.

 * <p>

 * The ISO-8601 calendar system is the modern civil calendar system used today

 * in most of the world. It is equivalent to the proleptic Gregorian calendar

 * system, in which today's rules for leap years are applied for all time.

 * For most applications written today, the ISO-8601 rules are entirely suitable.

 * However, any application that makes use of historical dates, and requires them

 * to be accurate will find the ISO-8601 approach unsuitable.

 *

 * @implSpec

 * This class is immutable and thread-safe.

 *

 * @since 1.8

 */

public final class LocalDateTime

        implements Temporal, TemporalAdjuster, ChronoLocalDateTime<LocalDate>, Serializable {

    /**

     * The minimum supported {@code LocalDateTime}, '-999999999-01-01T00:00:00'.

     * This is the local date-time of midnight at the start of the minimum date.

     * This combines {@link LocalDate#MIN} and {@link LocalTime#MIN}.

     * This could be used by an application as a "far past" date-time.

     */

    public static final LocalDateTime MIN = LocalDateTime.of(LocalDate.MIN, LocalTime.MIN);

    /**

     * The maximum supported {@code LocalDateTime}, '+999999999-12-31T23:59:59.999999999'.

     * This is the local date-time just before midnight at the end of the maximum date.

     * This combines {@link LocalDate#MAX} and {@link LocalTime#MAX}.

     * This could be used by an application as a "far future" date-time.

     */

    public static final LocalDateTime MAX = LocalDateTime.of(LocalDate.MAX, LocalTime.MAX);

    /**

     * Serialization version.

     */

    private static final long serialVersionUID = 6207766400415563566L;

    /**

     * The date part.

     */

    private final LocalDate date;

    /**

     * The time part.

     */

    private final LocalTime time;

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

    /**

     * Obtains the current date-time from the system clock in the default time-zone.

     * <p>

     * This will query the {@link Clock#systemDefaultZone() system clock} in the default

     * time-zone to obtain the current date-time.

     * <p>

     * Using this method will prevent the ability to use an alternate clock for testing

     * because the clock is hard-coded.

     *

     * @return the current date-time using the system clock and default time-zone, not null

     */

    public static LocalDateTime now() {

        return now(Clock.systemDefaultZone());

    }

    /**

     * Obtains the current date-time from the system clock in the specified time-zone.

     * <p>

     * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date-time.

     * Specifying the time-zone avoids dependence on the default time-zone.

     * <p>

     * Using this method will prevent the ability to use an alternate clock for testing

     * because the clock is hard-coded.

     *

     * @param zone  the zone ID to use, not null

     * @return the current date-time using the system clock, not null

     */

    public static LocalDateTime now(ZoneId zone) {

        return now(Clock.system(zone));

    }

    /**

     * Obtains the current date-time from the specified clock.

     * <p>

     * This will query the specified clock to obtain the current date-time.

     * Using this method allows the use of an alternate clock for testing.

     * The alternate clock may be introduced using {@link Clock dependency injection}.

     *

     * @param clock  the clock to use, not null

     * @return the current date-time, not null

     */

    public static LocalDateTime now(Clock clock) {

        Objects.requireNonNull(clock, "clock");

        final Instant now = clock.instant();  // called once

        ZoneOffset offset = clock.getZone().getRules().getOffset(now);

        return ofEpochSecond(now.getEpochSecond(), now.getNano(), offset);

    }

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

    /**

     * Obtains an instance of {@code LocalDateTime} from year, month,

     * day, hour and minute, setting the second and nanosecond to zero.

     * <p>

     * This returns a {@code LocalDateTime} with the specified year, month,

     * day-of-month, hour and minute.

     * The day must be valid for the year and month, otherwise an exception will be thrown.

     * The second and nanosecond fields will be set to zero.

     *

     * @param year  the year to represent, from MIN_YEAR to MAX_YEAR

     * @param month  the month-of-year to represent, not null

     * @param dayOfMonth  the day-of-month to represent, from 1 to 31

     * @param hour  the hour-of-day to represent, from 0 to 23

     * @param minute  the minute-of-hour to represent, from 0 to 59

     * @return the local date-time, not null

     * @throws DateTimeException if the value of any field is out of range,

     *  or if the day-of-month is invalid for the month-year

     */

    public static LocalDateTime of(int year, Month month, int dayOfMonth, int hour, int minute) {

        LocalDate date = LocalDate.of(year, month, dayOfMonth);

        LocalTime time = LocalTime.of(hour, minute);

        return new LocalDateTime(date, time);

    }

    /**

     * Obtains an instance of {@code LocalDateTime} from year, month,

     * day, hour, minute and second, setting the nanosecond to zero.

     * <p>

     * This returns a {@code LocalDateTime} with the specified year, month,

     * day-of-month, hour, minute and second.

     * The day must be valid for the year and month, otherwise an exception will be thrown.

     * The nanosecond field will be set to zero.

     *

     * @param year  the year to represent, from MIN_YEAR to MAX_YEAR

     * @param month  the month-of-year to represent, not null

     * @param dayOfMonth  the day-of-month to represent, from 1 to 31

     * @param hour  the hour-of-day to represent, from 0 to 23

     * @param minute  the minute-of-hour to represent, from 0 to 59

     * @param second  the second-of-minute to represent, from 0 to 59

     * @return the local date-time, not null

     * @throws DateTimeException if the value of any field is out of range,

     *  or if the day-of-month is invalid for the month-year

     */

    public static LocalDateTime of(int year, Month month, int dayOfMonth, int hour, int minute, int second) {

        LocalDate date = LocalDate.of(year, month, dayOfMonth);

        LocalTime time = LocalTime.of(hour, minute, second);

        return new LocalDateTime(date, time);

    }

    /**

     * Obtains an instance of {@code LocalDateTime} from year, month,

     * day, hour, minute, second and nanosecond.

     * <p>

     * This returns a {@code LocalDateTime} with the specified year, month,

     * day-of-month, hour, minute, second and nanosecond.

     * The day must be valid for the year and month, otherwise an exception will be thrown.

     *

     * @param year  the year to represent, from MIN_YEAR to MAX_YEAR

     * @param month  the month-of-year to represent, not null

     * @param dayOfMonth  the day-of-month to represent, from 1 to 31

     * @param hour  the hour-of-day to represent, from 0 to 23

     * @param minute  the minute-of-hour to represent, from 0 to 59

     * @param second  the second-of-minute to represent, from 0 to 59

     * @param nanoOfSecond  the nano-of-second to represent, from 0 to 999,999,999

     * @return the local date-time, not null

     * @throws DateTimeException if the value of any field is out of range,

     *  or if the day-of-month is invalid for the month-year

     */

    public static LocalDateTime of(int year, Month month, int dayOfMonth, int hour, int minute, int second, int nanoOfSecond) {

        LocalDate date = LocalDate.of(year, month, dayOfMonth);

        LocalTime time = LocalTime.of(hour, minute, second, nanoOfSecond);

        return new LocalDateTime(date, time);

    }

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

    /**

     * Obtains an instance of {@code LocalDateTime} from year, month,

     * day, hour and minute, setting the second and nanosecond to zero.

     * <p>

     * This returns a {@code LocalDateTime} with the specified year, month,

     * day-of-month, hour and minute.

     * The day must be valid for the year and month, otherwise an exception will be thrown.

     * The second and nanosecond fields will be set to zero.

     *

     * @param year  the year to represent, from MIN_YEAR to MAX_YEAR

     * @param month  the month-of-year to represent, from 1 (January) to 12 (December)

     * @param dayOfMonth  the day-of-month to represent, from 1 to 31

     * @param hour  the hour-of-day to represent, from 0 to 23

     * @param minute  the minute-of-hour to represent, from 0 to 59

     * @return the local date-time, not null

     * @throws DateTimeException if the value of any field is out of range,

     *  or if the day-of-month is invalid for the month-year

     */

    public static LocalDateTime of(int year, int month, int dayOfMonth, int hour, int minute) {

        LocalDate date = LocalDate.of(year, month, dayOfMonth);

        LocalTime time = LocalTime.of(hour, minute);

        return new LocalDateTime(date, time);

    }

    /**

     * Obtains an instance of {@code LocalDateTime} from year, month,

     * day, hour, minute and second, setting the nanosecond to zero.

     * <p>

     * This returns a {@code LocalDateTime} with the specified year, month,

     * day-of-month, hour, minute and second.

     * The day must be valid for the year and month, otherwise an exception will be thrown.

     * The nanosecond field will be set to zero.

     *

     * @param year  the year to represent, from MIN_YEAR to MAX_YEAR

     * @param month  the month-of-year to represent, from 1 (January) to 12 (December)

     * @param dayOfMonth  the day-of-month to represent, from 1 to 31

     * @param hour  the hour-of-day to represent, from 0 to 23

     * @param minute  the minute-of-hour to represent, from 0 to 59

     * @param second  the second-of-minute to represent, from 0 to 59

     * @return the local date-time, not null

     * @throws DateTimeException if the value of any field is out of range,

     *  or if the day-of-month is invalid for the month-year

     */

    public static LocalDateTime of(int year, int month, int dayOfMonth, int hour, int minute, int second) {

        LocalDate date = LocalDate.of(year, month, dayOfMonth);

        LocalTime time = LocalTime.of(hour, minute, second);

        return new LocalDateTime(date, time);

    }

    /**

     * Obtains an instance of {@code LocalDateTime} from year, month,

     * day, hour, minute, second and nanosecond.

     * <p>

     * This returns a {@code LocalDateTime} with the specified year, month,

     * day-of-month, hour, minute, second and nanosecond.

     * The day must be valid for the year and month, otherwise an exception will be thrown.

     *

     * @param year  the year to represent, from MIN_YEAR to MAX_YEAR

     * @param month  the month-of-year to represent, from 1 (January) to 12 (December)

     * @param dayOfMonth  the day-of-month to represent, from 1 to 31

     * @param hour  the hour-of-day to represent, from 0 to 23

     * @param minute  the minute-of-hour to represent, from 0 to 59

     * @param second  the second-of-minute to represent, from 0 to 59

     * @param nanoOfSecond  the nano-of-second to represent, from 0 to 999,999,999

     * @return the local date-time, not null

     * @throws DateTimeException if the value of any field is out of range,

     *  or if the day-of-month is invalid for the month-year

     */

    public static LocalDateTime of(int year, int month, int dayOfMonth, int hour, int minute, int second, int nanoOfSecond) {

        LocalDate date = LocalDate.of(year, month, dayOfMonth);

        LocalTime time = LocalTime.of(hour, minute, second, nanoOfSecond);

        return new LocalDateTime(date, time);

    }

    /**

     * Obtains an instance of {@code LocalDateTime} from a date and time.

     *

     * @param date  the local date, not null

     * @param time  the local time, not null

     * @return the local date-time, not null

     */

    public static LocalDateTime of(LocalDate date, LocalTime time) {

        Objects.requireNonNull(date, "date");

        Objects.requireNonNull(time, "time");

        return new LocalDateTime(date, time);

    }

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

    /**

     * Obtains an instance of {@code LocalDateTime} from an {@code Instant} and zone ID.

     * <p>

     * This creates a local date-time based on the specified instant.

     * First, the offset from UTC/Greenwich is obtained using the zone ID and instant,

     * which is simple as there is only one valid offset for each instant.

     * Then, the instant and offset are used to calculate the local date-time.

     *

     * @param instant  the instant to create the date-time from, not null

     * @param zone  the time-zone, which may be an offset, not null

     * @return the local date-time, not null

     * @throws DateTimeException if the result exceeds the supported range

     */

    public static LocalDateTime ofInstant(Instant instant, ZoneId zone) {

        Objects.requireNonNull(instant, "instant");

        Objects.requireNonNull(zone, "zone");

        ZoneRules rules = zone.getRules();

        ZoneOffset offset = rules.getOffset(instant);

        return ofEpochSecond(instant.getEpochSecond(), instant.getNano(), offset);

    }

    /**

     * Obtains an instance of {@code LocalDateTime} using seconds from the

     * epoch of 1970-01-01T00:00:00Z.

     * <p>

     * This allows the {@link ChronoField#INSTANT_SECONDS epoch-second} field

     * to be converted to a local date-time. This is primarily intended for

     * low-level conversions rather than general application usage.

     *

     * @param epochSecond  the number of seconds from the epoch of 1970-01-01T00:00:00Z

     * @param nanoOfSecond  the nanosecond within the second, from 0 to 999,999,999

     * @param offset  the zone offset, not null

     * @return the local date-time, not null

     * @throws DateTimeException if the result exceeds the supported range,

     *  or if the nano-of-second is invalid

     */

    public static LocalDateTime ofEpochSecond(long epochSecond, int nanoOfSecond, ZoneOffset offset) {

        Objects.requireNonNull(offset, "offset");

        NANO_OF_SECOND.checkValidValue(nanoOfSecond);

        long localSecond = epochSecond + offset.getTotalSeconds();  // overflow caught later

        long localEpochDay = Math.floorDiv(localSecond, SECONDS_PER_DAY);

        int secsOfDay = (int)Math.floorMod(localSecond, SECONDS_PER_DAY);

        LocalDate date = LocalDate.ofEpochDay(localEpochDay);

        LocalTime time = LocalTime.ofNanoOfDay(secsOfDay * NANOS_PER_SECOND + nanoOfSecond);

        return new LocalDateTime(date, time);

    }

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

    /**

     * Obtains an instance of {@code LocalDateTime} from a temporal object.

     * <p>

     * This obtains an offset time based on the specified temporal.

     * A {@code TemporalAccessor} represents an arbitrary set of date and time information,

     * which this factory converts to an instance of {@code LocalDateTime}.

     * <p>

     * The conversion extracts and combines the {@code LocalDate} and the

     * {@code LocalTime} from the temporal object.

     * Implementations are permitted to perform optimizations such as accessing

     * those fields that are equivalent to the relevant objects.

     * <p>

     * This method matches the signature of the functional interface {@link TemporalQuery}

     * allowing it to be used as a query via method reference, {@code LocalDateTime::from}.

     *

     * @param temporal  the temporal object to convert, not null

     * @return the local date-time, not null

     * @throws DateTimeException if unable to convert to a {@code LocalDateTime}

     */

    public static LocalDateTime from(TemporalAccessor temporal) {

        if (temporal instanceof LocalDateTime) {

            return (LocalDateTime) temporal;

        } else if (temporal instanceof ZonedDateTime) {

            return ((ZonedDateTime) temporal).toLocalDateTime();

        } else if (temporal instanceof OffsetDateTime) {

            return ((OffsetDateTime) temporal).toLocalDateTime();

        }

        try {

            LocalDate date = LocalDate.from(temporal);

            LocalTime time = LocalTime.from(temporal);

            return new LocalDateTime(date, time);

        } catch (DateTimeException ex) {

            throw new DateTimeException("Unable to obtain LocalDateTime from TemporalAccessor: " +

                    temporal + " of type " + temporal.getClass().getName(), ex);

        }

    }

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

    /**

     * Obtains an instance of {@code LocalDateTime} from a text string such as {@code 2007-12-03T10:15:30}.

     * <p>

     * The string must represent a valid date-time and is parsed using

     * {@link java.time.format.DateTimeFormatter#ISO_LOCAL_DATE_TIME}.

     *

     * @param text  the text to parse such as "2007-12-03T10:15:30", not null

     * @return the parsed local date-time, not null

     * @throws DateTimeParseException if the text cannot be parsed

     */

    public static LocalDateTime parse(CharSequence text) {

        return parse(text, DateTimeFormatter.ISO_LOCAL_DATE_TIME);

    }

    /**

     * Obtains an instance of {@code LocalDateTime} from a text string using a specific formatter.

     * <p>

     * The text is parsed using the formatter, returning a date-time.

     *

     * @param text  the text to parse, not null

     * @param formatter  the formatter to use, not null

     * @return the parsed local date-time, not null

     * @throws DateTimeParseException if the text cannot be parsed

     */

    public static LocalDateTime parse(CharSequence text, DateTimeFormatter formatter) {

        Objects.requireNonNull(formatter, "formatter");

        return formatter.parse(text, LocalDateTime::from);

    }

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

    /**

     * Constructor.

     *

     * @param date  the date part of the date-time, validated not null

     * @param time  the time part of the date-time, validated not null

     */

    private LocalDateTime(LocalDate date, LocalTime time) {

        this.date = date;

        this.time = time;

    }

    /**

     * Returns a copy of this date-time with the new date and time, checking

     * to see if a new object is in fact required.

     *

     * @param newDate  the date of the new date-time, not null

     * @param newTime  the time of the new date-time, not null

     * @return the date-time, not null

     */

    private LocalDateTime with(LocalDate newDate, LocalTime newTime) {

        if (date == newDate && time == newTime) {

            return this;

        }

        return new LocalDateTime(newDate, newTime);

    }

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

    /**

     * Checks if the specified field is supported.

     * <p>

     * This checks if this date-time can be queried for the specified field.

     * If false, then calling the {@link #range(TemporalField) range},

     * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)}

     * methods will throw an exception.