/*******************************************************************************
 * Copyright (c) 2004, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal.intro.impl.util;

import java.net.URL;

import org.eclipse.core.runtime.FileLocator;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.ImageRegistry;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.internal.intro.impl.IIntroConstants;
import org.eclipse.ui.internal.intro.impl.IntroPlugin;
import org.osgi.framework.Bundle;

/**
 * Convenience class for Images.
 */
public final class ImageUtil {

    /**
     * Image keys, to be used by plugin (intro) registry.
     */
    // Default images
    public static final String DEFAULT_ROOT_LINK = "rootLink"; //$NON-NLS-1$
    public static final String DEFAULT_SMALL_ROOT_LINK = "rootLinkSmall"; //$NON-NLS-1$
    public static final String DEFAULT_FORM_BG = "formBg"; //$NON-NLS-1$
    public static final String DEFAULT_LINK = "link"; //$NON-NLS-1$

    // Standby images
    public static final String BACK = "back"; //$NON-NLS-1$
    public static final String HELP_TOPIC = "helpTopic"; //$NON-NLS-1$

    // Launch bar image
    public static final String RESTORE_WELCOME = "restoreWelcome"; //$NON-NLS-1$

    // Viewer images
    public static final String INTRO_MODEL_LEAF = "leaf"; //$NON-NLS-1$
    public static final String INTRO_MODEL_CONTAINER = "container"; //$NON-NLS-1$
    public static final String OPEN_ITNRO_VIEW = "introView"; //$NON-NLS-1$
    
    public static final String CONFIG_EXTENSION = "configExtension";//$NON-NLS-1$

    // Image location
    public static final String ICONS_PATH = "$nl$/icons/"; //$NON-NLS-1$

    /**
     * Convenience method to create an image descriptor from the Intro plugin.
     * 
     * Method assumes that images are under the "icons" directory, so don't
     * append that directory name for "imageName".
     */
    public static ImageDescriptor createImageDescriptor(String imageName) {
        return createImageDescriptor(Platform
            .getBundle(IIntroConstants.PLUGIN_ID), ICONS_PATH + imageName);
    }
    
    /**
     * Convenience method to create an image descriptor.
     * 
     */
    public static ImageDescriptor createImageDescriptor(Bundle bundle,
            String imageName) {
        try {
            URL imageUrl = FileLocator.find(bundle, new Path(imageName), null);
            if (imageUrl != null) {
                ImageDescriptor desc = ImageDescriptor.createFromURL(imageUrl);
                return desc;
            }
        } catch (Exception e) {
            // Should never be here.
            Log.error("could not create Image Descriptor", e); //$NON-NLS-1$
        }
        Log.warning("could not create Image Descriptor for: " + imageName //$NON-NLS-1$
                + " in bundle: " + bundle.getSymbolicName()); //$NON-NLS-1$
        return ImageDescriptor.getMissingImageDescriptor();
    }
    
    /**
     * Convenience method to create an image descriptor.
     * 
     */
    public static ImageDescriptor createImageDescriptor(IPath base,
            String imageName) {
        try {
            URL imageUrl = new URL(base.append(imageName).toOSString());
            if (imageUrl != null) {
                ImageDescriptor desc = ImageDescriptor.createFromURL(imageUrl);
                return desc;
            }
        } catch (Exception e) {
            // Should never be here.
            Log.error("could not create Image Descriptor", e); //$NON-NLS-1$
        }
        Log.warning("could not create Image Descriptor for: " + imageName); //$NON-NLS-1$
        return ImageDescriptor.getMissingImageDescriptor();
    }

    /**
     * Convenience method to create an image from the Intro plugin.
     * 
     * Method assumes that images are under the "icons" directory, so don't
     * append that directory name for "imageName".
     */
    public static Image createImage(String imageName) {
        try {
            ImageDescriptor imageDsc = createImageDescriptor(imageName);
            return imageDsc.createImage();
        } catch (Exception e) {
            // Should never be here.
            Log.error("could not create Image", e); //$NON-NLS-1$
            return ImageDescriptor.getMissingImageDescriptor().createImage();
        }
    }

    /**
     * Util method for image re-use in Intro Plugin.
     * 
     * @param key
     * @return
     */
    public static Image getImage(String key) {
        // INTRO: Image registry should not have the same life span
        // as the intro plug-in. It should be disposed when
        // presentation is disposed, otherwise images will
        // stay around once Inro has been loaded.
        return IntroPlugin.getDefault().getVolatileImageRegistry().get(key);
    }

    public static boolean hasImage(String key) {
        ImageRegistry registry = IntroPlugin.getDefault().getVolatileImageRegistry();
        return (registry.getDescriptor(key) != null);
    }

    /**
     * Register an image descriptor in the Intro Plugin image registry. Has no
     * effect if the key has already been registered.
     * 
     * @param key
     * @param imageName
     */
    public static void registerImage(String key, String imageName) {
        ImageRegistry registry = IntroPlugin.getDefault().getVolatileImageRegistry();
        if (registry.getDescriptor(key) != null)
            // key has already been registered. do nothing.
            return;
        registry.put(key, createImageDescriptor(imageName));
    }

    public static void registerImage(String key, Bundle bundle, String imageName) {

        ImageRegistry registry = IntroPlugin.getDefault().getVolatileImageRegistry();
        if (registry.getDescriptor(key) != null)
            // key has already been registered. do nothing.
            return;
        registry.put(key, createImageDescriptor(bundle, imageName));
    }
    
    public static void registerImage(String key, IPath base, String imageName) {
        ImageRegistry registry = IntroPlugin.getDefault().getVolatileImageRegistry();
        if (registry.getDescriptor(key) != null)
            // key has already been registered. do nothing.
            return;
        registry.put(key, createImageDescriptor(base, imageName));
    }
}
