/*

 * 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

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 * 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,

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 *

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

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/*

 * 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.temporal;

import java.time.Duration;

/**

 * A standard set of date periods units.

 * <p>

 * This set of units provide unit-based access to manipulate a date, time or date-time.

 * The standard set of units can be extended by implementing {@link TemporalUnit}.

 * <p>

 * These units are intended to be applicable in multiple calendar systems.

 * For example, most non-ISO calendar systems define units of years, months and days,

 * just with slightly different rules.

 * The documentation of each unit explains how it operates.

 *

 * <h3>Specification for implementors</h3>

 * This is a final, immutable and thread-safe enum.

 *

 * @since 1.8

 */

public enum ChronoUnit implements TemporalUnit {

    /**

     * Unit that represents the concept of a nanosecond, the smallest supported unit of time.

     * For the ISO calendar system, it is equal to the 1,000,000,000th part of the second unit.

     */

    NANOS("Nanos", Duration.ofNanos(1)),

    /**

     * Unit that represents the concept of a microsecond.

     * For the ISO calendar system, it is equal to the 1,000,000th part of the second unit.

     */

    MICROS("Micros", Duration.ofNanos(1000)),

    /**

     * Unit that represents the concept of a millisecond.

     * For the ISO calendar system, it is equal to the 1000th part of the second unit.

     */

    MILLIS("Millis", Duration.ofNanos(1000_000)),

    /**

     * Unit that represents the concept of a second.

     * For the ISO calendar system, it is equal to the second in the SI system

     * of units, except around a leap-second.

     */

    SECONDS("Seconds", Duration.ofSeconds(1)),

    /**

     * Unit that represents the concept of a minute.

     * For the ISO calendar system, it is equal to 60 seconds.

     */

    MINUTES("Minutes", Duration.ofSeconds(60)),

    /**

     * Unit that represents the concept of an hour.

     * For the ISO calendar system, it is equal to 60 minutes.

     */

    HOURS("Hours", Duration.ofSeconds(3600)),

    /**

     * Unit that represents the concept of half a day, as used in AM/PM.

     * For the ISO calendar system, it is equal to 12 hours.

     */

    HALF_DAYS("HalfDays", Duration.ofSeconds(43200)),

    /**

     * Unit that represents the concept of a day.

     * For the ISO calendar system, it is the standard day from midnight to midnight.

     * The estimated duration of a day is {@code 24 Hours}.

     * <p>

     * When used with other calendar systems it must correspond to the day defined by

     * the rising and setting of the Sun on Earth. It is not required that days begin

     * at midnight - when converting between calendar systems, the date should be

     * equivalent at midday.

     */

    DAYS("Days", Duration.ofSeconds(86400)),

    /**

     * Unit that represents the concept of a week.

     * For the ISO calendar system, it is equal to 7 days.

     * <p>

     * When used with other calendar systems it must correspond to an integral number of days.

     */

    WEEKS("Weeks", Duration.ofSeconds(7 * 86400L)),

    /**

     * Unit that represents the concept of a month.

     * For the ISO calendar system, the length of the month varies by month-of-year.

     * The estimated duration of a month is one twelfth of {@code 365.2425 Days}.

     * <p>

     * When used with other calendar systems it must correspond to an integral number of days.

     */

    MONTHS("Months", Duration.ofSeconds(31556952L / 12)),

    /**

     * Unit that represents the concept of a year.

     * For the ISO calendar system, it is equal to 12 months.

     * The estimated duration of a year is {@code 365.2425 Days}.

     * <p>

     * When used with other calendar systems it must correspond to an integral number of days

     * or months roughly equal to a year defined by the passage of the Earth around the Sun.

     */

    YEARS("Years", Duration.ofSeconds(31556952L)),

    /**

     * Unit that represents the concept of a decade.

     * For the ISO calendar system, it is equal to 10 years.

     * <p>

     * When used with other calendar systems it must correspond to an integral number of days

     * and is normally an integral number of years.

     */

    DECADES("Decades", Duration.ofSeconds(31556952L * 10L)),

    /**

     * Unit that represents the concept of a century.

     * For the ISO calendar system, it is equal to 100 years.

     * <p>

     * When used with other calendar systems it must correspond to an integral number of days

     * and is normally an integral number of years.

     */

    CENTURIES("Centuries", Duration.ofSeconds(31556952L * 100L)),

    /**

     * Unit that represents the concept of a millennium.

     * For the ISO calendar system, it is equal to 1000 years.

     * <p>

     * When used with other calendar systems it must correspond to an integral number of days

     * and is normally an integral number of years.

     */

    MILLENNIA("Millennia", Duration.ofSeconds(31556952L * 1000L)),

    /**

     * Unit that represents the concept of an era.

     * The ISO calendar system doesn't have eras thus it is impossible to add

     * an era to a date or date-time.

     * The estimated duration of the era is artificially defined as {@code 1,000,00,000 Years}.

     * <p>

     * When used with other calendar systems there are no restrictions on the unit.

     */

    ERAS("Eras", Duration.ofSeconds(31556952L * 1000_000_000L)),

    /**

     * Artificial unit that represents the concept of forever.

     * This is primarily used with {@link TemporalField} to represent unbounded fields

     * such as the year or era.

     * The estimated duration of the era is artificially defined as the largest duration

     * supported by {@code Duration}.

     */

    FOREVER("Forever", Duration.ofSeconds(Long.MAX_VALUE, 999_999_999));

    private final String name;

    private final Duration duration;

    private ChronoUnit(String name, Duration estimatedDuration) {

        this.name = name;

        this.duration = estimatedDuration;

    }

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

    @Override

    public String getName() {

        return name;

    }

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

    /**

     * Gets the estimated duration of this unit in the ISO calendar system.

     * <p>

     * All of the units in this class have an estimated duration.

     * Days vary due to daylight saving time, while months have different lengths.

     *

     * @return the estimated duration of this unit, not null

     */

    @Override

    public Duration getDuration() {

        return duration;

    }

    /**

     * Checks if the duration of the unit is an estimate.

     * <p>

     * All time units in this class are considered to be accurate, while all date

     * units in this class are considered to be estimated.

     * <p>

     * This definition ignores leap seconds, but considers that Days vary due to

     * daylight saving time and months have different lengths.

     *

     * @return true if the duration is estimated, false if accurate

     */

    @Override

    public boolean isDurationEstimated() {

        return isDateUnit();

    }

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

    /**

     * Checks if this unit is a date unit.

     *

     * @return true if a date unit, false if a time unit

     */

    public boolean isDateUnit() {

        return this.compareTo(DAYS) >= 0;

    }

    /**

     * Checks if this unit is a time unit.

     *

     * @return true if a time unit, false if a date unit

     */

    public boolean isTimeUnit() {

        return this.compareTo(DAYS) < 0;

    }

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

    @Override

        if (this == FOREVER) {

            return false;

        }

        if (temporal instanceof ChronoLocalDate) {

            return isDateUnit();

        }

        if (temporal instanceof ChronoLocalDateTime || temporal instanceof ChronoZonedDateTime) {

            return true;

        }

    }

    @SuppressWarnings("unchecked")

    @Override

    }

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

    @Override

    }

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

    @Override

    public String toString() {

        return getName();

    }

}