/******************************************************************************* 
 * Copyright (c) 2008 Red Hat, Inc. 
 * Distributed under license by Red Hat, Inc. All rights reserved. 
 * This program is 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: 
 * Xavier Coulon - Initial API and implementation 
 ******************************************************************************/

package org.jboss.tools.ws.jaxrs.ui;

import java.net.URL;

import org.eclipse.core.resources.IMarker;
import org.eclipse.core.runtime.FileLocator;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.ImageRegistry;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.viewers.DecorationOverlayIcon;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.jboss.tools.ws.jaxrs.ui.internal.utils.Logger;
import org.osgi.framework.BundleContext;

/**
 * The activator class controls the plug-in life cycle
 */
public class JBossJaxrsUIPlugin extends AbstractUIPlugin {

	// The plug-in ID
	public static final String PLUGIN_ID = "org.jboss.tools.ws.jaxrs.ui"; //$NON-NLS-1$

	// The shared instance
	private static JBossJaxrsUIPlugin plugin;
	
	private ImageRegistry imageRegistry = null;

	private ImageRegistry imageDescriptorRegistry = null;
	/**
	 * The constructor
	 */
	public JBossJaxrsUIPlugin() {
	}

	/*
	 * (non-Javadoc)
	 * @see org.eclipse.ui.plugin.AbstractUIPlugin#start(org.osgi.framework.BundleContext)
	 */
	public void start(BundleContext context) throws Exception {
		super.start(context);
		plugin = this;
		imageRegistry = new ImageRegistry(Display.getDefault());
		imageDescriptorRegistry = new ImageRegistry(Display.getDefault());
	}

	/*
	 * (non-Javadoc)
	 * @see org.eclipse.ui.plugin.AbstractUIPlugin#stop(org.osgi.framework.BundleContext)
	 */
	public void stop(BundleContext context) throws Exception {
		plugin = null;
		imageRegistry.dispose();
		imageDescriptorRegistry.dispose();
		super.stop(context);
	}

	/**
	 * Returns the shared instance
	 *
	 * @return the shared instance
	 */
	public static JBossJaxrsUIPlugin getDefault() {
		return plugin;
	}
	
	/**
	 * Creates an image by loading it from a file in the plugin's images
	 * directory, and then keeping it in the plugin's image registry for later calls.
	 * 
	 * @param imagePath path to the image, relative to the /icons directory of the plugin
	 * @return The image object loaded from the image file
	 */
	public final ImageDescriptor getImageDescriptor(final String imagePath) {
		if(imageDescriptorRegistry.get(imagePath) == null) {
			imageDescriptorRegistry.put(imagePath, createImageDescriptor(imagePath, 0));
		}
		return imageDescriptorRegistry.getDescriptor(imagePath);
	}

	/**
	 * Creates an image by loading it from a file in the plugin's images
	 * directory, and then keeping it in the plugin's image registry for later calls.
	 * 
	 * @param imagePath path to the image, relative to the /icons directory of the plugin
	 * @return The image object loaded from the image file
	 */
	public final Image getImage(final String imagePath) {
		return getImage(imagePath, 0);
	}
	
	/**
	 * Creates an image by loading it from a file in the plugin's images
	 * directory, adding a decorator at the bottom left corner of it, and then
	 * keeping it in the plugin's image registry for later calls.
	 * 
	 * @param imagePath
	 *            path to the image, relative to the /icons directory of the
	 *            plugin
	 * @return The image object loaded from the image file
	 */
	public final Image getImage(final String imagePath, final int level) {
		Logger.debug("Loading image {} with decorator level {}", imagePath, level);
		if(imagePath == null) {
			return null;
		}
		final String imageKey = imagePath.concat(String.valueOf(level));
		if(imageRegistry.get(imageKey) == null) {
			final ImageDescriptor imageDescriptor = createImageDescriptor(imagePath, level);
			imageRegistry.put(imageKey, imageDescriptor.createImage());
		}
		return imageRegistry.get(imageKey);
	}
	
	/**
	 * Creates an image descriptor by loading it from a file in the plugin's images
	 * directory.
	 * 
	 * @param imagePath path to the image, relative to the /icons directory of the plugin
	 * @return The image object loaded from the image file
	 */
	public final ImageDescriptor createImageDescriptor(final String imagePath, final int problemLevel) {
		final IPath imageFilePath = new Path("/icons/" + imagePath);
		final URL imageFileUrl = FileLocator.find(this.getBundle(), imageFilePath, null);
		final ImageDescriptor baseImageDescriptor = ImageDescriptor.createFromURL(imageFileUrl);
		switch (problemLevel) {
		case IMarker.SEVERITY_ERROR:
			return createDecoratedImageDescriptor(baseImageDescriptor, "org.eclipse.jface.fieldassist.IMG_DEC_FIELD_ERROR");
		case IMarker.SEVERITY_WARNING:
			return createDecoratedImageDescriptor(baseImageDescriptor, "org.eclipse.jface.fieldassist.IMG_DEC_FIELD_WARNING");

		default:
			return baseImageDescriptor;
		}
	}

	/**
	 * Creates an image from the given baseImage with the given decorator at the bottom left corner
	 * @param baseImage
	 * @param decoratorId
	 * @return
	 * 
	 * @see https://bugs.eclipse.org/bugs/show_bug.cgi?id=383810 to use PlatformUI.getWorkbench().getSharedImages().getImage(ISharedImages.IMG_DEC_FIELD_ERROR),
	 * which returns null for now.
	 */
	private ImageDescriptor createDecoratedImageDescriptor(final ImageDescriptor baseImageDescriptor, String decoratorId) {
		final ImageDescriptor decoratorDescriptor = JFaceResources.getImageRegistry().getDescriptor(decoratorId);
		final Image baseImage = baseImageDescriptor.createImage();
		final DecorationOverlayIcon result = new DecorationOverlayIcon(baseImage, new ImageDescriptor[] { null, null, decoratorDescriptor, null, null },
				new Point(16, 16));
		return result;
	}
	
}
