package org.hwo.models;

import java.util.Arrays;
import java.util.LinkedList;

import javax.swing.ComboBoxModel;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListDataListener;

public class ComboBoxHistoryModel<E> implements ComboBoxModel<E> {

	private LinkedList<ListDataListener> listDataListeners = new LinkedList();
	private LinkedList<E> items = new LinkedList();
	
	private E selectedItem;
	private int historySize;
	
	
	public ComboBoxHistoryModel()
	{
		this.selectedItem = null;
		this.historySize = 10;
	}
	public ComboBoxHistoryModel(int historySize)
	{
		this.selectedItem = null;
		this.historySize = historySize;
	}
	
	
	private void fireContentsChanged()
	{
		ListDataEvent lde = new ListDataEvent(this, ListDataEvent.CONTENTS_CHANGED, 0, this.items.size());
		for (ListDataListener l: listDataListeners) {
			l.contentsChanged(lde);
		}
	}
	
	@Override
	public void addListDataListener(ListDataListener arg0) {
		listDataListeners.add(arg0);
	}

	@Override
	public E getElementAt(int arg0) {
		return items.get(arg0);
	}

	@Override
	public int getSize() {
		return items.size();
	}

	@Override
	public void removeListDataListener(ListDataListener arg0) {
		listDataListeners.remove(arg0);		
	}

	@Override
	public Object getSelectedItem() {
		return selectedItem;
	}

	@Override
	public void setSelectedItem(Object arg0) {
		selectedItem = (E)arg0;
		if (items.contains(selectedItem)) {
			items.remove(selectedItem);
		}
		items.add(0,selectedItem);
		clampHistory();
	}

	public int getHistorySize() {
		return historySize;
	}

	public void setHistorySize(int historySize) {
		this.historySize = historySize;
	}
	
	public Object[] getItems(){
		return items.toArray();
	}
	
	public E[] getItems(E[] at) {
		return items.toArray(at);
	}
	
	public void setItems(E[] items) {
		this.items.clear();
		this.items.addAll(Arrays.asList(items));
		if (!this.items.contains(selectedItem)) {
			selectedItem = null;
		}
		if (!clampHistory())
			fireContentsChanged();
	}

	private boolean clampHistory() {
		if (items.size() > historySize) {
			while (items.size() > historySize) {
				items.removeLast();
			}
			fireContentsChanged();
			return true;
		}
		return false;
	}
	
	public void addElement(E element) {
		this.items.add(0,element);
		if (!clampHistory())
			fireContentsChanged();
	}
	
	public void clear() {
		items.clear();
		fireContentsChanged();
	}

	public boolean contains(E val) {
		return items.contains(val);
	}
	
}