/*
 * Joda Software License, Version 1.0
 *
 *
 * Copyright (c) 2001-2004 Stephen Colebourne.  
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Joda project (http://www.joda.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The name "Joda" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact licence@joda.org.
 *
 * 5. Products derived from this software may not be called "Joda",
 *    nor may "Joda" appear in their name, without prior written
 *    permission of the Joda project.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 JODA AUTHORS OR THE PROJECT
 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Joda project and was originally 
 * created by Stephen Colebourne <scolebourne@joda.org>. For more
 * information on the Joda project, please see <http://www.joda.org/>.
 */
package org.joda.time.field;

import java.io.Serializable;
import java.util.Locale;

import org.joda.time.Chronology;
import org.joda.time.DateTimeField;
import org.joda.time.DateTimeFieldType;
import org.joda.time.DateTimeUtils;
import org.joda.time.DurationField;
import org.joda.time.ReadableInstant;
import org.joda.time.ReadablePartial;

/**
 * AbstractReadableInstantFieldProperty is a base class for binding a
 * ReadableInstant to a DateTimeField.
 * <p>
 * It allows the date and time manipulation code to be field based yet
 * still easy to use.
 * <p>
 * AbstractReadableInstantFieldProperty itself is thread-safe and immutable,
 * but the ReadableInstant being operated on may be mutable and not
 * thread-safe.
 *
 * @author Stephen Colebourne
 * @author Brian S O'Neill
 * @since 1.0
 */
public abstract class AbstractReadableInstantFieldProperty implements Serializable {
    
    /** Serialization version. */
    private static final long serialVersionUID = 1971226328211649661L;

    /**
     * Constructor.
     */
    public AbstractReadableInstantFieldProperty() {
        super();
    }

    //-----------------------------------------------------------------------
    /**
     * Gets the field being used.
     * 
     * @return the field
     */
    public abstract DateTimeField getField();

    /**
     * Gets the field type being used.
     * 
     * @return the field type
     */
    public DateTimeFieldType getFieldType() {
        return getField().getType();
    }

    /**
     * Gets the name of the field.
     * 
     * @return the field name
     */
    public String getName() {
        return getField().getName();
    }

    /**
     * Gets the instant being used.
     * 
     * @return the instant
     */
    public abstract ReadableInstant getReadableInstant();

    //-----------------------------------------------------------------------
    /**
     * Gets a value from the instant.
     * 
     * @return the current value
     * @see DateTimeField#get
     */
    public int get() {
        return getField().get(getReadableInstant().getMillis());
    }

    /**
     * Gets a text value from the instant.
     * 
     * @param locale  optional locale to use for selecting a text symbol
     * @return the current text value
     * @see DateTimeField#getAsText
     */
    public String getAsText(Locale locale) {
        return getField().getAsText(getReadableInstant().getMillis(), locale);
    }

    /**
     * Gets a text value from the instant.
     * 
     * @return the current text value
     * @see DateTimeField#getAsText
     */
    public final String getAsText() {
        return getAsText(null);
    }

    /**
     * Gets a short text value from the instant.
     * 
     * @param locale  optional locale to use for selecting a text symbol
     * @return the current text value
     * @see DateTimeField#getAsShortText
     */
    public String getAsShortText(Locale locale) {
        return getField().getAsShortText(getReadableInstant().getMillis(), locale);
    }

    /**
     * Gets a short text value from the instant.
     * 
     * @return the current text value
     * @see DateTimeField#getAsShortText
     */
    public final String getAsShortText() {
        return getAsShortText(null);
    }

    //-----------------------------------------------------------------------
    /**
     * Returns the difference between this field property instant and the one
     * passed in, in the units of this field. The sign of the difference
     * matches that of compareTo. In other words, this field property's instant
     * is the minuend.
     *
     * @param instant  the subtrahend, null means now
     * @return the difference in the units of this field
     * @see DateTimeField#getDifference
     */
    public int getDifference(ReadableInstant instant) {
        if (instant == null) {
            return getField().getDifference(getReadableInstant().getMillis(), DateTimeUtils.currentTimeMillis());
        }
        return getField().getDifference(getReadableInstant().getMillis(), instant.getMillis());
    }

    /**
     * Returns the difference between this field property instant and the one
     * passed in, in the units of this field. The sign of the difference
     * matches that of compareTo. In other words, this field property's instant
     * is the minuend.
     *
     * @param instant  the subtrahend, null means now
     * @return the difference in the units of this field
     * @see DateTimeField#getDifference
     */
    public long getDifferenceAsLong(ReadableInstant instant) {
        if (instant == null) {
            return getField().getDifferenceAsLong(getReadableInstant().getMillis(), DateTimeUtils.currentTimeMillis());
        }
        return getField().getDifferenceAsLong(getReadableInstant().getMillis(), instant.getMillis());
    }

    //-----------------------------------------------------------------------
    /**
     * Returns the duration per unit value of this field. For example, if this
     * field represents "hour of day", then the duration is an hour.
     *
     * @return the duration of this field, or UnsupportedDurationField
     */
    public DurationField getDurationField() {
        return getField().getDurationField();
    }

    /**
     * Returns the range duration of this field. For example, if this field
     * represents "hour of day", then the range duration is a day.
     *
     * @return the range duration of this field, or null if field has no range
     */
    public DurationField getRangeDurationField() {
        return getField().getRangeDurationField();
    }

    /**
     * Gets whether this field is leap.
     * 
     * @return true if a leap field
     * @see DateTimeField#isLeap
     */
    public boolean isLeap() {
        return getField().isLeap(getReadableInstant().getMillis());
    }

    /**
     * Gets the amount by which this field is leap.
     * 
     * @return the amount by which the field is leap
     * @see DateTimeField#getLeapAmount
     */
    public int getLeapAmount() {
        return getField().getLeapAmount(getReadableInstant().getMillis());
    }

    /**
     * If this field were to leap, then it would be in units described by the
     * returned duration. If this field doesn't ever leap, null is returned.
     */
    public DurationField getLeapDurationField() {
        return getField().getLeapDurationField();
    }

    //-----------------------------------------------------------------------
    /**
     * Gets the minimum value for the field ignoring the current time.
     * 
     * @return the minimum value
     * @see DateTimeField#getMinimumValue
     */
    public int getMinimumValueOverall() {
        return getField().getMinimumValue();
    }

    /**
     * Gets the minimum value for the field.
     * 
     * @return the minimum value
     * @see DateTimeField#getMinimumValue
     */
    public int getMinimumValue() {
        return getField().getMinimumValue(getReadableInstant().getMillis());
    }

    /**
     * Gets the maximum value for the field ignoring the current time.
     * 
     * @return the maximum value
     * @see DateTimeField#getMaximumValue
     */
    public int getMaximumValueOverall() {
        return getField().getMaximumValue();
    }

    /**
     * Gets the maximum value for the field.
     * 
     * @return the maximum value
     * @see DateTimeField#getMaximumValue
     */
    public int getMaximumValue() {
        return getField().getMaximumValue(getReadableInstant().getMillis());
    }

    /**
     * Gets the maximum text length for the field.
     * 
     * @param locale  optional locale to use for selecting a text symbol
     * @return the maximum length
     * @see DateTimeField#getMaximumTextLength
     */
    public int getMaximumTextLength(Locale locale) {
        return getField().getMaximumTextLength(locale);
    }

    /**
     * Gets the maximum short text length for the field.
     * 
     * @param locale  optional locale to use for selecting a text symbol
     * @return the maximum length
     * @see DateTimeField#getMaximumShortTextLength
     */
    public int getMaximumShortTextLength(Locale locale) {
        return getField().getMaximumShortTextLength(locale);
    }


    /**
     * Returns the fractional duration milliseconds of this field.
     *
     * @see DateTimeField#remainder
     * @return remainder duration, in milliseconds
     */
    public long remainder() {
        return getField().remainder(getReadableInstant().getMillis());
    }

    //-----------------------------------------------------------------------
    /**
     * Compare this field to the same field on another instant.
     * <p>
     * The comparison is based on the value of the same field type, irrespective
     * of any difference in chronology. Thus, if this property represents the
     * hourOfDay field, then the hourOfDay field of the other instant will be queried
     * whether in the same chronology or not.
     * 
     * @param instant  the instant to compare to
     * @return negative value if this is less, 0 if equal, or positive value if greater
     * @throws IllegalArgumentException if the instant is null
     */
    public int compareTo(ReadableInstant instant) {
        if (instant == null) {
            throw new IllegalArgumentException("The instant must not be null");
        }
        int thisValue = get();
        Chronology chrono = DateTimeUtils.getChronology(instant.getChronology());
        int otherValue = getFieldType().getField(chrono).get(instant.getMillis());
        if (thisValue < otherValue) {
            return -1;
        } else if (thisValue > otherValue) {
            return 1;
        } else {
            return 0;
        }
    }

    /**
     * Compare this field to the same field on another partial instant.
     * <p>
     * The comparison is based on the value of the same field type, irrespective
     * of any difference in chronology. Thus, if this property represents the
     * hourOfDay field, then the hourOfDay field of the other partial will be queried
     * whether in the same chronology or not.
     * 
     * @param partial  the partial to compare to
     * @return negative value if this is less, 0 if equal, or positive value if greater
     * @throws IllegalArgumentException if the instant is null
     * @throws IllegalArgumentException if the field of this property cannot be queried
     *  on the specified instant
     */
    public int compareTo(ReadablePartial partial) {
        if (partial == null) {
            throw new IllegalArgumentException("The instant must not be null");
        }
        int thisValue = get();
        int otherValue = partial.get(getFieldType());
        if (thisValue < otherValue) {
            return -1;
        } else if (thisValue > otherValue) {
            return 1;
        } else {
            return 0;
        }
    }

    //-----------------------------------------------------------------------
    /**
     * Compares this property to another.
     * 
     * @param object  the object to compare to
     * @return true if equal
     */
    public boolean equals(Object object) {
        if (this == object) {
            return true;
        }
        if (object instanceof AbstractReadableInstantFieldProperty) {
            AbstractReadableInstantFieldProperty other = (AbstractReadableInstantFieldProperty) object;
            if (get() == other.get() &&
                getFieldType() == other.getFieldType() &&
                getReadableInstant().getChronology() == other.getReadableInstant().getChronology()) {
                return true;
            }
        }
        return false;
    }

    //-----------------------------------------------------------------------
    /**
     * Output a debugging string.
     * 
     * @return debugging string
     */
    public String toString() {
        return "Property[" + getName() + "]";
    }

}