package com.digi.config.util;

import java.io.File;
import java.io.Serializable;
import java.net.URL;
import java.util.*;
import javax.swing.ImageIcon;


/**
 * This is a special purpose resource bundle that allows the Config UI classes 
 * to easily access imageIcons. Use this resource bundle similar to any other 
 * resource bundle. For example, the following code segment shows how to access 
 * and use the bundle to get imageIcons:
 * <code>
 *    ImageResourceBundle irb = ResourceBundle.
 *       getBundle("com.digi.util.ImageResourceBundle");
 *    ImageIcon icon = irb.getImageIcon("PrintThis");
 * </code>
 *
 * The lookup is actually performed in a two step process. First, the name of 
 * the image file is looked up in the property file 
 * "ConfigImgResourceBundle.properties". This file contains a collection of
 * imageName->ImageFileName pairs. Once the file name has been located, an 
 * IconImage is created for that file and is returned to the caller.
 * <br>
 * Note: Since the image file names are located in a resource file, it is easy 
 * to provide locale specific icons by providing a property file for each locale
 * and changing the file name mappings to the appropriate locale icons.
 *
 *
 */
public class ImageResourceBundle extends ResourceBundle {

    //==========================================================================
    //=                  Object attributes
    //==========================================================================

    /** The property file containing the mapping from image name to image file */
    private String imageResourceBundleName;

    /** The resource bundle containing the mapping from image name to image file */
    private ResourceBundle imageResourceBundle;

    /** The location of the image files */
    private static String imagesDirectory="/com/digi/config/images/";

    /** Cache the images so don't load multiple times */
    private Map imageMap=new HashMap();


    /**
     * Construct a new ImageResourceBundle.
     *
     * The constructor ensures that the image resource bundle has been located so that
     * subsequent lookups can use it.
     */
    public ImageResourceBundle(String imageResourceBundleName) throws MissingResourceException {
        try {
            if (imageResourceBundle==null) {
                imageResourceBundle=ResourceBundle.getBundle(imageResourceBundleName);
                this.imageResourceBundleName = imageResourceBundleName;
            }
        }
        catch (MissingResourceException exc) {
            // If this happens, it means we cant find the resource bundle and
            // therefore we won't find
            // any image icons. This is obviously bad so log an error and
            // throw the exception.
            SystemLog.log("MissingBundle",
                new Serializable[] { imageResourceBundleName}, exc);
            throw exc;
        }
    }


    /**
     * Returns all the available image keys in the image resource bundle.
     *
     * @return Enumeration of image keys
     */
    public Enumeration getKeys() {
        return imageResourceBundle.getKeys();
    }

    /**
     * Fetches the proper image icon for the specified image name.
     * This method accomplishes its work by first looking up the image file 
     * name in the image resource bundle and then locates and creates an icon 
     * for the specified file.  If the image is not found, it will log a message 
     * and return a default image.
     *
     * @return ImageIcon object associated with the key
     */
    public Object handleGetObject(String key) {

        // Check for a cached image
        Object returnValue=imageMap.get(key);
        if (returnValue!=null) {
            return returnValue;
        }

        // Get the image file name
        String imageName=null;
        try {
            imageName=imageResourceBundle.getString(key);
        }
        catch (MissingResourceException exc) {
            imageName=key;
            //return null;

// decided that its best to not load a default image when requested image is not found
//             SystemLog.log("MissingBundleKey",
//                 new Serializable[] { imageResourceBundleName, key},
//                 new Serializable[] { exc});
//             // try a default image instead
//             try {
//                 imageName=imageResourceBundle.getString("NotFoundImage");
//             }
//             catch (MissingResourceException exc2) {
//                 SystemLog.log("MissingBundleKey",
//                     new Serializable[] {imageResourceBundleName, "NotFoundImage"},
//                     exc2 );
//                 return null;
//             }
        }

        // Create an ImageIcon from the image file
        if (imageName!=null) {
            //System.out.println("Found image key in bundle... looking for image file "+imageName);
            String imageFileName=imagesDirectory+imageName;
            URL icon=this.getClass().getResource(imageFileName);
            if (icon==null) {
                //SystemLog.log("MissingIcon", new Serializable[] { imageName});
                return null;
            }
            returnValue=new ImageIcon(icon);
            imageMap.put(key, returnValue);
        }
        return returnValue;
    }

    /**
     * Fetches the proper image icon for the specified image name.
     * This method accomplishes its work by first looking up the image file 
     * name in the image resource bundle and then locates and creates an icon 
     * for the specified file.  If the image is not found, it will log a message 
     * and return a default image.
     *
     * @return ImageIcon object associated with the key
     */
    public ImageIcon getImageIcon(String key) {
        return(ImageIcon)handleGetObject(key);
    }


}