/**
 *#########################################################################
 *
 * A component of the Gatherer application, part of the Greenstone digital
 * library suite from the New Zealand Digital Library Project at the
 * University of Waikato, New Zealand.
 *
 * <BR><BR>
 *
 * Author: John Thompson, Greenstone Digital Library, University of Waikato
 *
 * <BR><BR>
 *
 * Copyright (C) 1999 New Zealand Digital Library Project
 *
 * <BR><BR>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * <BR><BR>
 *
 * This program 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 for more details.
 *
 * <BR><BR>
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *########################################################################
 */
package org.greenstone.gatherer.checklist;

/**************************************************************************************
 * Title:        Gatherer
 * Description:  The Gatherer: a tool for gathering and enriching a digital collection.
 * Company:      The University of Waikato
 * Written:      14/08/02
 * Revised:      
 **************************************************************************************/
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.*;
import org.greenstone.gatherer.checklist.Entry;

/** This class provides a visual component that has the form of a list, as provided by JList but uses JCheckBox for data selection. Thus several elements can be 'ticked' in the list, and this selection returned using the method getSelected().<BR>Parts of this code modified from Trevor Harmon's posting on www.dejanews.com.
 * @author John Thompson
 * @version 2.3
 */ 
// ####################################################################################
// Optimization                          Saving
// ####################################################################################
// Vector -> ArrayList                   + Processor
// ####################################################################################
public class CheckList
    extends JList {
    /** The border used when a list row is not in focus. */
    protected static Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);
    
    private boolean show_selected_row = true;
    /** Constructor. */
    public CheckList(boolean show_selected_row) {
	super();
	this.show_selected_row = show_selected_row;
	setCellRenderer(new CellRenderer());
	setModel(new DefaultListModel());
	setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
	addMouseListener(new CheckListListener());
    }
    /** Constructor.
     * @param list_data An ArrayList of entries for this checklist.
     * @see org.greenstone.gatherer.checklist.CheckList.Entry
     */
    public CheckList(ArrayList list_data, boolean show_selected_row) {
	super();
	this.show_selected_row = show_selected_row;
	// Create a new model.
	DefaultListModel model = new DefaultListModel();
	for(int i = 0; i < list_data.size(); i++) {
	    Entry entry = null;
	    Object temp = list_data.get(i);
	    if(temp instanceof Entry) {
		entry = (Entry) temp;
	    }
	    else {
		entry = new Entry(list_data.get(i));
	    }
	    temp = null;
	    String name = entry.toString();
	    int index = 0;
	    boolean found = false;
	    while(index < model.size() && !found) {
		Object sibling = model.getElementAt(index);
		if(name.compareTo(sibling.toString()) <= 0) {
		    model.add(index, entry);
		    found = true;
		}
		index++;
	    }
	    if(!found) {
		model.addElement(entry);
	    }
	}
	setModel(model);
	setCellRenderer(new CellRenderer());
	addMouseListener(new CheckListListener());
	setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    }

    /** Constructor. */
    public CheckList(ListModel data_model, boolean show_selected_row) {
	super(data_model);
	this.show_selected_row = show_selected_row;
	setCellRenderer(new CellRenderer());
	addMouseListener(new CheckListListener());
	setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    }

    public void addEntry(Entry entry) {
	DefaultListModel model = (DefaultListModel) getModel();
	String name = entry.toString();
	int index = 0;
	boolean found = false;
	while(index < model.size() && !found) {
	    Object sibling = model.getElementAt(index);
	    if(name.compareTo(sibling.toString()) <= 0) {
		model.add(index, entry);
		found = true;
	    }
	    index++;
	    sibling = null;
	}
	if(!found) {
	    model.addElement(entry);
	}		  
	name = null;
	model = null;
    }

    public Entry get(int index) {
	DefaultListModel model = (DefaultListModel) getModel();
	return (Entry) model.get(index);
    }

    /** Retrieve the currently ticked entries from this list.
     * @return An <strong>ArrayList</strong> containing only those entries from the initial list that are checked.
     * @see org.greenstone.gatherer.checklist.CheckList.Entry
     */
    public ArrayList getSelected() {
	ArrayList result = new ArrayList();
	DefaultListModel model = (DefaultListModel) getModel();
	int size = model.size();
	for(int i = 0; i < size; i++) {
	    Entry entry = (Entry) model.get(i);
	    if(entry.isSelected()) {
		result.add(entry.getObject());
	    }
	}
	return result;
    }

    public boolean isSelected(int index) {
	DefaultListModel model = (DefaultListModel) getModel();
	Entry entry = (Entry) model.get(index);
	return entry.isSelected();
    }

    public boolean isSelectionEmpty() {
	DefaultListModel model = (DefaultListModel) getModel();
	int size = model.size();
	for(int i = 0; i < size; i++) {
	    Entry entry = (Entry) model.get(i);
	    if(entry.isSelected()) {
		entry = null;
		model = null;
		return false;
	    }
	    entry = null;
	}
	model = null;
	return true;
    }

    public int getEntryCount() {
	return getModel().getSize();
    }

    public void setListData(Object[] list_data) {
	// Create a new model.
	DefaultListModel model = new DefaultListModel();
	for(int i = 0; i < list_data.length; i++) {
	    Entry entry = null;
	    Object temp = list_data[i];
	    if(temp instanceof Entry) {
		entry = (Entry) temp;
	    }
	    else {
		entry = new Entry(temp);
	    }
	    temp = null;
	    String name = entry.toString();
	    int index = 0;
	    boolean found = false;
	    while(index < model.size() && !found) {
		Object sibling = model.getElementAt(index);
		if(name.compareTo(sibling.toString()) <= 0) {
		    model.add(index, entry);
		    found = true;
		}
		index++;
	    }
	    if(!found) {
		model.addElement(entry);
	    }
	}
	setModel(model);
    }

    /** Checks the entries in the list whose name appear in the given array.
     * @param names The name of entries to be checked as a <strong>String[]</strong>.
     * @see org.greenstone.gatherer.checklist.CheckList.Entry
     */
    public void setSelected(String names[]) {
	DefaultListModel model = (DefaultListModel) getModel();
	int size = model.size();
	for(int i = 0; i < size; i++) {
	    Entry entry = (Entry) model.get(i);
	    for(int j = 0; names != null && j < names.length; j++) {
		if(entry.toString().equals(names[j])) {
		    entry.setSelected(true);
		}
	    }
	}		  
    }

    private void selectionChanged(int index) {
	fireSelectionValueChanged(index, index, false);
    }

    /** A custom list cell renderer for producing rows which contain clickable check boxes. */
    protected class CellRenderer 
	implements ListCellRenderer {
	/** Return a component that has been configured to display the specified value. That component's paint method is then called to "render" the cell. If it is necessary to compute the dimensions of a list because the list cells do not have a fixed size, this method is called to generate a component on which getPreferredSize  can be invoked.
	 * @param list The </strong>JList</strong> we're painting.
	 * @param value The value returned by list.getModel().getElementAt(index), as an <strong>Object</strong>.
	 * @param index The cells index as an <i>int</i>.
	 * @param is_selected <i>true</i> if the specified cell was selected, <i>false</i> otherwise.
	 * @param cell_has_focus <i>true</i> if and only if the specified cell has the focus.
	 * @return A <strong>Component</strong> whose paint() method will render the specified value.
	 */
	public Component getListCellRendererComponent(JList list, Object value, int index, boolean is_selected, boolean cell_has_focus) {
	    JCheckBox checkbox = (JCheckBox) value;
	    if(show_selected_row) {
		checkbox.setBackground(is_selected ? list.getSelectionBackground() : list.getBackground());
		checkbox.setForeground(is_selected ? list.getSelectionForeground() : list.getForeground());
		checkbox.setBorderPainted(true);
	    }
	    else {
		checkbox.setBackground(list.getBackground());
		checkbox.setForeground(list.getForeground());
		checkbox.setBorderPainted(false);
	    }
	    checkbox.setEnabled(list.isEnabled());
	    checkbox.setFont(list.getFont());
	    checkbox.setFocusPainted(false);
	    checkbox.setBorder((is_selected) ? UIManager.getBorder("List.focusCellHighlightBorder") : noFocusBorder);
	    return checkbox;
	}
    }
    /** Listens for clicks apon the checks within the list, and updates as necessary. */
    private class CheckListListener 
	extends MouseAdapter {

	//private Entry previous_checkbox = null;
	/** Called whenever the mouse is clicked over our list. We find the nearest checkbox and change its state.
	 * @param e A <strong>MouseEvent</strong> containing everything you ever wanted to know about the mouse event but were afraid to ask.
	 */
	public void mousePressed(MouseEvent e) {
	    JList list = (JList) e.getSource();
	    int index = list.locationToIndex(e.getPoint());
	    Entry checkbox = (Entry)list.getModel().getElementAt(index);
	    if(!checkbox.isFixed()) {
		checkbox.setSelected(!checkbox.isSelected());
	    }
	    checkbox.grabFocus();
	    // Fire a selection changed event
	    selectionChanged(index);
	}
    }
}