package edu.hws.eck.umb.palette;

import java.util.ArrayList;

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

/**
 * A simple class that simply holds a palette length and a palette offset.
 * These values determine how the colors from a palette are assigned to
 * interation counts in a MandelbrotDisplay.
 */
public class PaletteMapping implements Cloneable {
	
	private final ChangeEvent changeEvent = new ChangeEvent(this);
	private ArrayList<ChangeListener> listeners = new ArrayList<ChangeListener>();
	
	private int length;
	private int offset;
	
	public PaletteMapping() {
	}
	
	public PaletteMapping(int length, int offset) {
		this.length = length;
		this.offset = offset;
	}
	
	public int getLength() {
		return length;
	}

	/**
	 * Set the palette length, which should be greater than or equal to zero.
	 * A value of zero means that the number of colors in the palette will be
	 * equal to the maximum number of iterations in the MandelbrotDisplay.
	 */
	public void setLength(int length) {
		if (length < 0)
			length = 0;
		if (this.length == length)
			return;
		this.length = length;
		changed();
	}

	public int getOffset() {
		return offset;
	}

	/**
	 * Set the offset for the palette.  Colors in the palette are rotated by
	 * this many positions withion the array of colors.
	 */
	public void setOffset(int offset) {
		if (this.offset == offset)
			return;
		this.offset = offset;
		changed();
	}
	
	/**
	 * Add a listener that will be notified of any changes in this object.
	 */
	public void addChangeListener(ChangeListener l) {
		if (!listeners.contains(l))
			listeners.add(l);
	}
	
	/**
	 * Remove a registered listener from this object (if present).
	 * @param l
	 */
	public void removeChangeListener(ChangeListener l) {
		listeners.remove(l);
	}
	
	public boolean equals(Object obj) {
		if (obj == null || !(obj instanceof PaletteMapping))
			return false;
		PaletteMapping that = (PaletteMapping)obj;
		return that.length == length && that.offset == offset;
	}
	
	public PaletteMapping clone() {
		return new PaletteMapping(length,offset);
	}
	
	private void changed() {
		for (ChangeListener l : listeners)
			l.stateChanged(changeEvent);
	}

}