/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 * 
 *    (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library 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
 *    Lesser General Public License for more details.
 */
package org.geotools.gui.swing.icon;

import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.ResourceBundle;
import java.util.WeakHashMap;

import javax.swing.ImageIcon;

/**
 * IconBundle, manage icons and avoid double loading
 * 
 * @author Johann Sorel
 *
 * @source $URL$
 */
public class IconBundle {

    private static IconBundle instance;
    public static final ImageIcon EMPTY_ICON = new ImageIcon(IconBundle.class.getResource("/org/geotools/gui/swing/icon/blanc.png"));
    private List<ResourceBundle> bundles = new ArrayList<ResourceBundle>();
    private WeakHashMap<String, ImageIcon> iconsmap = new WeakHashMap<String, ImageIcon>();

    private IconBundle() {
        bundles.add( ResourceBundle.getBundle("org/geotools/gui/swing/icon/defaultset") );
        bundles.add( ResourceBundle.getBundle("org/geotools/gui/swing/icon/crystalset") );
        bundles.add( ResourceBundle.getBundle("org/geotools/gui/swing/icon/jsorelset") );
    }

    private URL getURL(String adress, Class base) {

        if (adress.startsWith("/")) {
            adress = adress.substring(1);
        }

        URL url = null;

        try {
            url = base.getClassLoader().getResource(adress);
        } catch (Exception e) {
        }

        try {
            if (url == null) {
                url = base.getClassLoader().getResource("/" + adress);
            }
        } catch (Exception e) {
        }

        try {
            if (url == null) {
                url = base.getResource(adress);
            }
        } catch (Exception e) {
        }

        try {
            if (url == null) {
                url = base.getResource("/" + adress);
            }
        } catch (Exception e) {
        }

        return url;
    }

    private ImageIcon getIcon(URL url) {
        if (url == null) {
            return EMPTY_ICON;
        } else {
            return new ImageIcon(url);
        }
    }

    /**
     * get the ImageIcon matching the key String.
     * return a blanc imageIcon size 1x1 if the key isn't found.
     * @param key
     * @return ImageIcon
     */
    public ImageIcon getIcon(String key) {
        return getIcon(key, IconBundle.class);
    }

    public ImageIcon getIcon(String key, Class base) {

        if (key == null) {
            return EMPTY_ICON;
        }
        ImageIcon icon = null;

        if (iconsmap.containsKey(key)) {
            icon = iconsmap.get(key);
        } else {
            String adress = getValue(key);

            if (adress != null) {
                icon = getIcon(getURL(adress, base));
                iconsmap.put(key, icon);
            }
        }

        if (icon == null) {
            icon = EMPTY_ICON;
        }

        return icon;
    }

    private String getValue(String key) {

        for(int i = bundles.size()-1; i>=0; i--){
            ResourceBundle bundle = bundles.get(i);
            
            if (existe(bundle, key)) {
                String adress = bundle.getString(key);
                if (adress.startsWith("$")) {
                    return getValue(adress.substring(1));
                } else {
                    return adress;
                }
            }
        }

        return null;
    }

    private boolean existe(ResourceBundle bundle, String key) {

        Enumeration<String> keys = bundle.getKeys();

        while (keys.hasMoreElements()) {
            if (key.equals(keys.nextElement())) {
                return true;
            }
        }

        return false;
    }

    /**
     * use your own icon bundle, property file should look like defaultset.properties.
     * if icon is missing the defautltset icon will be used
     * @param bundle ResourceBundle
     */
    public void addBundle(ResourceBundle bundle) {
        bundles.add(bundle);
    }

    public static IconBundle getResource() {
        if (instance == null) {
            instance = new IconBundle();
        }
        return instance;
    }
}