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 * Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.

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

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

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 * 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

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 *

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

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/*

 * Copyright (c) 2013, 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

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 */

package java.time.chrono;

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

import static java.time.temporal.ChronoUnit.DAYS;

import static java.time.temporal.ChronoUnit.MONTHS;

import static java.time.temporal.ChronoUnit.YEARS;

import java.io.DataInput;

import java.io.DataOutput;

import java.io.IOException;

import java.io.InvalidObjectException;

import java.io.ObjectInputStream;

import java.io.ObjectStreamException;

import java.io.Serializable;

import java.time.DateTimeException;

import java.time.temporal.ChronoUnit;

import java.time.temporal.Temporal;

import java.time.temporal.TemporalAccessor;

import java.time.temporal.TemporalAmount;

import java.time.temporal.TemporalQueries;

import java.time.temporal.TemporalUnit;

import java.time.temporal.UnsupportedTemporalTypeException;

import java.time.temporal.ValueRange;

import java.util.List;

import java.util.Objects;

/**

 * A period expressed in terms of a standard year-month-day calendar system.

 * <p>

 * This class is used by applications seeking to handle dates in non-ISO calendar systems.

 * For example, the Japanese, Minguo, Thai Buddhist and others.

 *

 * @implSpec

 * This class is immutable nad thread-safe.

 *

 * @since 1.8

 */

final class ChronoPeriodImpl

        implements ChronoPeriod, Serializable {

    // this class is only used by JDK chronology implementations and makes assumptions based on that fact

    /**

     * Serialization version.

     */

    @java.io.Serial

    private static final long serialVersionUID = 57387258289L;

    /**

     * The set of supported units.

     */

    private static final List<TemporalUnit> SUPPORTED_UNITS = List.of(YEARS, MONTHS, DAYS);

    /**

     * The chronology.

     */

    private final Chronology chrono;

    /**

     * The number of years.

     */

    final int years;

    /**

     * The number of months.

     */

    final int months;

    /**

     * The number of days.

     */

    final int days;

    /**

     * Creates an instance.

     */

    ChronoPeriodImpl(Chronology chrono, int years, int months, int days) {

        Objects.requireNonNull(chrono, "chrono");

        this.chrono = chrono;

        this.years = years;

        this.months = months;

        this.days = days;

    }

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

    @Override

    public long get(TemporalUnit unit) {

        if (unit == ChronoUnit.YEARS) {

            return years;

        } else if (unit == ChronoUnit.MONTHS) {

            return months;

        } else if (unit == ChronoUnit.DAYS) {

            return days;

        } else {

            throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);

        }

    }

    @Override

    public List<TemporalUnit> getUnits() {

        return ChronoPeriodImpl.SUPPORTED_UNITS;

    }

    @Override

    public Chronology getChronology() {

        return chrono;

    }

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

    @Override

    public boolean isZero() {

        return years == 0 && months == 0 && days == 0;

    }

    @Override

    public boolean isNegative() {

        return years < 0 || months < 0 || days < 0;

    }

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

    @Override

    public ChronoPeriod plus(TemporalAmount amountToAdd) {

        ChronoPeriodImpl amount = validateAmount(amountToAdd);

        return new ChronoPeriodImpl(

                chrono,

                Math.addExact(years, amount.years),

                Math.addExact(months, amount.months),

                Math.addExact(days, amount.days));

    }

    @Override

    public ChronoPeriod minus(TemporalAmount amountToSubtract) {

        ChronoPeriodImpl amount = validateAmount(amountToSubtract);

        return new ChronoPeriodImpl(

                chrono,

                Math.subtractExact(years, amount.years),

                Math.subtractExact(months, amount.months),

                Math.subtractExact(days, amount.days));

    }

    /**

     * Obtains an instance of {@code ChronoPeriodImpl} from a temporal amount.

     *

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

     * @return the period, not null

     */

    private ChronoPeriodImpl validateAmount(TemporalAmount amount) {

        Objects.requireNonNull(amount, "amount");

        if (amount instanceof ChronoPeriodImpl == false) {

            throw new DateTimeException("Unable to obtain ChronoPeriod from TemporalAmount: " + amount.getClass());

        }

        ChronoPeriodImpl period = (ChronoPeriodImpl) amount;

        if (chrono.equals(period.getChronology()) == false) {

            throw new ClassCastException("Chronology mismatch, expected: " + chrono.getId() + ", actual: " + period.getChronology().getId());

        }

        return period;

    }

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

    @Override

    public ChronoPeriod multipliedBy(int scalar) {

        if (this.isZero() || scalar == 1) {

            return this;

        }

        return new ChronoPeriodImpl(

                chrono,

                Math.multiplyExact(years, scalar),

                Math.multiplyExact(months, scalar),

                Math.multiplyExact(days, scalar));

    }

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

    @Override

    public ChronoPeriod normalized() {

        long monthRange = monthRange();

        if (monthRange > 0) {

            long totalMonths = years * monthRange + months;

            long splitYears = totalMonths / monthRange;

            int splitMonths = (int) (totalMonths % monthRange);  // no overflow

            if (splitYears == years && splitMonths == months) {

                return this;

            }

            return new ChronoPeriodImpl(chrono, Math.toIntExact(splitYears), splitMonths, days);

        }

        return this;

    }

    /**

     * Calculates the range of months.

     *

     * @return the month range, -1 if not fixed range

     */

    private long monthRange() {

        ValueRange startRange = chrono.range(MONTH_OF_YEAR);

        if (startRange.isFixed() && startRange.isIntValue()) {

            return startRange.getMaximum() - startRange.getMinimum() + 1;

        }

        return -1;

    }

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

    @Override

    public Temporal addTo(Temporal temporal) {

        validateChrono(temporal);

        if (months == 0) {

            if (years != 0) {

                temporal = temporal.plus(years, YEARS);

            }

        } else {

            long monthRange = monthRange();

            if (monthRange > 0) {

                temporal = temporal.plus(years * monthRange + months, MONTHS);

            } else {

                if (years != 0) {

                    temporal = temporal.plus(years, YEARS);

                }

                temporal = temporal.plus(months, MONTHS);

            }

        }

        if (days != 0) {

            temporal = temporal.plus(days, DAYS);

        }

        return temporal;

    }

    @Override

    public Temporal subtractFrom(Temporal temporal) {

        validateChrono(temporal);

        if (months == 0) {

            if (years != 0) {

                temporal = temporal.minus(years, YEARS);

            }

        } else {

            long monthRange = monthRange();

            if (monthRange > 0) {

                temporal = temporal.minus(years * monthRange + months, MONTHS);

            } else {

                if (years != 0) {

                    temporal = temporal.minus(years, YEARS);

                }

                temporal = temporal.minus(months, MONTHS);

            }

        }

        if (days != 0) {

            temporal = temporal.minus(days, DAYS);

        }

        return temporal;

    }

    /**

     * Validates that the temporal has the correct chronology.

     */

    private void validateChrono(TemporalAccessor temporal) {

        Objects.requireNonNull(temporal, "temporal");

        Chronology temporalChrono = temporal.query(TemporalQueries.chronology());

        if (temporalChrono != null && chrono.equals(temporalChrono) == false) {

            throw new DateTimeException("Chronology mismatch, expected: " + chrono.getId() + ", actual: " + temporalChrono.getId());

        }

    }

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

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (obj instanceof ChronoPeriodImpl) {

            ChronoPeriodImpl other = (ChronoPeriodImpl) obj;

            return years == other.years && months == other.months &&

                    days == other.days && chrono.equals(other.chrono);

        }

        return false;

    }

    @Override

    public int hashCode() {

        return (years + Integer.rotateLeft(months, 8) + Integer.rotateLeft(days, 16)) ^ chrono.hashCode();

    }

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

    @Override

    public String toString() {

        if (isZero()) {

            return getChronology().toString() + " P0D";

        } else {

            StringBuilder buf = new StringBuilder();

            buf.append(getChronology().toString()).append(' ').append('P');

            if (years != 0) {

                buf.append(years).append('Y');

            }

            if (months != 0) {

                buf.append(months).append('M');

            }

            if (days != 0) {

                buf.append(days).append('D');

            }

            return buf.toString();

        }

    }

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

    /**

     * Writes the Chronology using a

     * <a href="{@docRoot}/serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.

     * <pre>

     *  out.writeByte(12);  // identifies this as a ChronoPeriodImpl

     *  out.writeUTF(getId());  // the chronology

     *  out.writeInt(years);

     *  out.writeInt(months);

     *  out.writeInt(days);

     * </pre>

     *

     * @return the instance of {@code Ser}, not null

     */

    @java.io.Serial

    protected Object writeReplace() {

        return new Ser(Ser.CHRONO_PERIOD_TYPE, this);

    }

    /**

     * Defend against malicious streams.

     *

     * @param s the stream to read

     * @throws InvalidObjectException always

     */

    @java.io.Serial

    private void readObject(ObjectInputStream s) throws ObjectStreamException {

        throw new InvalidObjectException("Deserialization via serialization delegate");

    }

    void writeExternal(DataOutput out) throws IOException {

        out.writeUTF(chrono.getId());

        out.writeInt(years);

        out.writeInt(months);

        out.writeInt(days);

    }

    static ChronoPeriodImpl readExternal(DataInput in) throws IOException {

        Chronology chrono = Chronology.of(in.readUTF());

        int years = in.readInt();

        int months = in.readInt();

        int days = in.readInt();

        return new ChronoPeriodImpl(chrono, years, months, days);

    }

}