/*
 * Copyright (c) 2002-2006 JGoodies Karsten Lentzsch. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * 
 *  o Redistributions of source code must retain the above copyright notice, 
 *    this list of conditions and the following disclaimer. 
 *     
 *  o 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. 
 *     
 *  o Neither the name of JGoodies Karsten Lentzsch 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 com.jgoodies.binding.adapter;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.Serializable;

import javax.swing.BoundedRangeModel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.EventListenerList;

import com.jgoodies.binding.value.ValueModel;

/**
 * Converts a ValueModel to the <code>BoundedRangeModel</code> interface.
 * Honors an upper and lower bound and returns the adapter's minimum
 * in case the subject value is <code>null</code>.<p>
 * 
 * <strong>Example:</strong><pre>
 * int minSaturation = 0;
 * int maxSaturation = 255;
 * PresentationModel pm = new PresentationModel(settings);
 * ValueModel saturationModel = pm.getModel("saturation");
 * JSlider saturationSlider = new JSlider(
 *     new BoundedRangeAdapter(saturationModel, 
 *                             0, 
 *                             minSaturation, 
 *                             maxSaturation));
 * </pre>
 *
 * @author  Karsten Lentzsch
 * @version $Revision: 1.2 $
 * 
 * @see javax.swing.JSlider
 */
public final class BoundedRangeAdapter implements BoundedRangeModel, Serializable {
        
    /**
     * Only one ChangeEvent is needed per model instance since the
     * event's only (read-only) state is the source property.  The source
     * of events generated here is always "this".
     */
    private transient ChangeEvent changeEvent = null;

    /** 
     * The listeners observing model changes. 
     */
    private final EventListenerList listenerList = new EventListenerList();

    private final ValueModel subject;

    private int theExtent = 0;
    private int min = 0;
    private int max = 100;
    private boolean isAdjusting = false;
    
    
    // Instance Creation ***************************************************

    /**
     * Constructs a BoundedRangeAdapter on the given subject 
     * using the specified extend, minimum and maximum values.

     * @param subject         the underlying ValueModel that provides the value
     * @param extent          the extent to be set
     * @param min             the minimum to be set
     * @param max             the maximum to be set
     * @throws IllegalArgumentException if the following constraints aren't 
     *     satisfied: <code>min <= initial subject value <= value+extent <= max</code>
     */
    public BoundedRangeAdapter(
        ValueModel subject,
        int extent,
        int min,
        int max) {
        this.subject = subject;
        Object subjectValue = subject.getValue();
        int initialValue = subjectValue == null
            ? min 
            : ((Integer) subjectValue).intValue();
        initialize(initialValue, extent, min, max);
        subject.addValueChangeListener(new SubjectValueChangeHandler());
    }
    
    
    // ************************************************************************

    /**
     * Returns this model's extent.
     * 
     * @return the model's extent
     * @see #setExtent(int)
     * @see BoundedRangeModel#getExtent()
     */
    public int getExtent() {
        return theExtent;
    }

    /**
     * Returns this model's upper bound, the maximum.
     * 
     * @return  the model's maximum
     * @see #setMaximum(int)
     * @see BoundedRangeModel#getMaximum()
     */
    public int getMaximum() {
        return max;
    }

    /**
     * Returns this model's lower bound, the minimum.
     * 
     * @return the model's minimum
     * @see #setMinimum(int)
     * @see BoundedRangeModel#getMinimum()
     */
    public int getMinimum() {
        return min;
    }

    /**
     * Returns the current subject value, or the minimum if
     * the subject value is <code>null</code>.
     * 
     * @return the model's current value
     * @see #setValue(int)
     * @see BoundedRangeModel#getValue()
     */
    public int getValue() {
        Object subjectValue = subject.getValue();
        return subjectValue == null
            ? getMinimum()
            : ((Integer) subjectValue).intValue();
    }
    

    /**
     * Returns true if the value is in the process of changing
     * as a result of actions being taken by the user.
     *
     * @return the value of the valueIsAdjusting property
     * @see #setValue(int)
     * @see BoundedRangeModel#getValueIsAdjusting()
     */
    public boolean getValueIsAdjusting() {
        return isAdjusting;
    }

    /** 
     * Sets the extent to <I>n</I>. Ensures that <I>n</I> 
     * is greater than or equal to zero and falls within the adapter's 
     * constraints:
     * <pre>
     *     minimum <= value <= value+extent <= maximum
     * </pre>
     * 
     * @param n  the new extent before ensuring a non-negative number
     * @see BoundedRangeModel#setExtent(int)
     */
    public void setExtent(int n) {
        int newExtent = Math.max(0, n);
        int value = getValue();
        if (value + newExtent > max) {
            newExtent = max - value;
        }
        setRangeProperties(value, newExtent, min, max, isAdjusting);
    }

    /** 
     * Sets the maximum to <I>n</I>. Ensures that <I>n</I> 
     * and the other three properties obey this adapter's constraints:
     * <pre>
     *     minimum <= value <= value+extent <= maximum
     * </pre>
     * 
     * @param n the new maximum before ensuring this adapter's constraints
     * @see BoundedRangeModel#setMaximum(int)
     */
    public void setMaximum(int n) {
        int newMin = Math.min(n, min);
        int newValue = Math.min(n, getValue());
        int newExtent = Math.min(n - newValue, theExtent);
        setRangeProperties(newValue, newExtent, newMin, n, isAdjusting);
    }

    /** 
     * Sets the minimum to <I>n</I>. Ensures that <I>n</I> 
     * and the other three properties obey this adapter's constraints:
     * <pre>
     *     minimum <= value <= value+extent <= maximum
     * </pre>
     * 
     * @param n   the new minimum before ensuring constraints
     * @see #getMinimum()
     * @see BoundedRangeModel#setMinimum(int)
     */
    public void setMinimum(int n) {
        int newMax = Math.max(n, max);
        int newValue = Math.max(n, getValue());
        int newExtent = Math.min(newMax - newValue, theExtent);
        setRangeProperties(newValue, newExtent, n, newMax, isAdjusting);
    }

    /**
     * Sets all of the BoundedRangeModel properties after forcing
     * the arguments to obey the usual constraints:
     * <pre>
     *     minimum <= value <= value+extent <= maximum
     * </pre><p>
     * 
     * At most, one ChangeEvent is generated.
     * 
     * @param newValue   the value to be set
     * @param newExtent  the extent to be set
     * @param newMin     the minimum to be set
     * @param newMax     the maximum to be set
     * @param adjusting  true if there are other pending changes
     * @see BoundedRangeModel#setRangeProperties(int, int, int, int, boolean)
     * @see #setValue(int)
     * @see #setExtent(int)
     * @see #setMinimum(int)
     * @see #setMaximum(int)
     * @see #setValueIsAdjusting(boolean)
     */
    public void setRangeProperties(
        int newValue,
        int newExtent,
        int newMin,
        int newMax,
        boolean adjusting) {
        if (newMin > newMax) {
            newMin = newMax;
        }
        if (newValue > newMax) {
            newMax = newValue;
        }
        if (newValue < newMin) {
            newMin = newValue;
        }

        /* Convert the addends to long so that extent can be 
         * Integer.MAX_VALUE without rolling over the sum.
         * A JCK test covers this, see bug 4097718.
         */
        if (((long) newExtent + (long) newValue) > newMax) {
            newExtent = newMax - newValue;
        }
        if (newExtent < 0) {
            newExtent = 0;
        }
        boolean isChange =
            (newValue != getValue())
                || (newExtent != theExtent)
                || (newMin != min)
                || (newMax != max)
                || (adjusting != isAdjusting);
        if (isChange) {
            setValue0(newValue);
            theExtent = newExtent;
            min = newMin;
            max = newMax;
            isAdjusting = adjusting;
            fireStateChanged();
        }
    }

    /** 
     * Sets the current value of the model. For a slider, that
     * determines where the knob appears. Ensures that the new 
     * value, <I>n</I> falls within the model's constraints:
     * <pre>
     *     minimum <= value <= value+extent <= maximum
     * </pre>
     * 
     * @param n   the new value before ensuring constraints
     * @see BoundedRangeModel#setValue(int)
     */
    public void setValue(int n) {
        int newValue = Math.max(n, min);
        if (newValue + theExtent > max) {
            newValue = max - theExtent;
        }
        setRangeProperties(newValue, theExtent, min, max, isAdjusting);
    }

    /**
     * Sets the valueIsAdjusting property.
     * 
     * @param b   the new value
     * @see #getValueIsAdjusting()
     * @see #setValue(int)
     * @see BoundedRangeModel#setValueIsAdjusting(boolean)
     */
    public void setValueIsAdjusting(boolean b) {
        setRangeProperties(getValue(), theExtent, min, max, b);
    }

    
    // Listeners and Events ***************************************************

    /**
     * Adds a ChangeListener.  The change listeners are run each
     * time any one of the Bounded Range model properties changes.
     *
     * @param l the ChangeListener to add
     * @see #removeChangeListener(ChangeListener)
     * @see BoundedRangeModel#addChangeListener(ChangeListener)
     */
    public void addChangeListener(ChangeListener l) {
        listenerList.add(ChangeListener.class, l);
    }

    
    /**
     * Removes a ChangeListener.
     *
     * @param l the ChangeListener to remove
     * @see #addChangeListener(ChangeListener)
     * @see BoundedRangeModel#removeChangeListener(ChangeListener)
     */
    public void removeChangeListener(ChangeListener l) {
        listenerList.remove(ChangeListener.class, l);
    }

    
    /** 
     * Runs each ChangeListeners stateChanged() method.
     * 
     * @see #setRangeProperties(int, int, int, int, boolean)
     * @see EventListenerList
     */
    protected void fireStateChanged() {
        Object[] listeners = listenerList.getListenerList();
        for (int i = listeners.length - 2; i >= 0; i -= 2) {
            if (listeners[i] == ChangeListener.class) {
                if (changeEvent == null) {
                    changeEvent = new ChangeEvent(this);
                }
                ((ChangeListener) listeners[i + 1]).stateChanged(changeEvent);
            }
        }
    }


    // Misc *******************************************************************
    
    /**
     * Initializes value, extent, minimum and maximum. Adjusting is false.
     * 
     * @param initialValue    the initialValue
     * @param extent          the extent to be set
     * @param minimum         the minimum to be set
     * @param maximum         the maximum to be set
     * 
     * @throws IllegalArgumentException if the following constraints
     *     aren't satisfied: <code>min <= value <= value+extent <= max</code>
     */
    private void initialize(int initialValue, int extent, int minimum, int maximum) {
        if ((maximum >= minimum)
            && (initialValue >= minimum)
            && ((initialValue + extent) >= initialValue)
            && ((initialValue + extent) <= maximum)) {
            this.theExtent = extent;
            this.min = minimum;
            this.max = maximum;
        } else {
            throw new IllegalArgumentException("invalid range properties");
        }
    }

    private void setValue0(int newValue) {
        subject.setValue(new Integer(newValue));
    }

    /**
     * Returns a string that displays all of the BoundedRangeModel properties.
     * 
     * @return a string representation of the properties
     */
    public String toString() {
        String modelString =
                  "value="
                + getValue()
                + ", "
                + "extent="
                + getExtent()
                + ", "
                + "min="
                + getMinimum()
                + ", "
                + "max="
                + getMaximum()
                + ", "
                + "adj="
                + getValueIsAdjusting();

        return getClass().getName() + "[" + modelString + "]";
    }
    
    
    /** 
     * Handles changes in the subject's value.
     */
    private final class SubjectValueChangeHandler implements PropertyChangeListener {

        /**
         * The subect's value has changed. Fires a state change so 
         * all registered listeners will be notified about the change.
         * 
         * @param evt the property change event fired by the subject
         */
        public void propertyChange(PropertyChangeEvent evt) {
            fireStateChanged();
        }

    }

    
}
