/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal.ide.registry;


import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;

import org.eclipse.core.resources.IMarker;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IPluginDescriptor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.internal.ide.IDEWorkbenchPlugin;
import org.eclipse.ui.internal.ide.IMarkerImageProvider;

/**
 * Implementation of a marker image registry which maps either
 * a marker type to a provider or to a static image.
 */
public class MarkerImageProviderRegistry {
	private static final String ATT_PROVIDER_CLASS = "class";//$NON-NLS-1$
	private static final String ATT_ICON = "icon";//$NON-NLS-1$
	private static final String ATT_MARKER_TYPE = "markertype";//$NON-NLS-1$
	private static final String ATT_ID = "id";//$NON-NLS-1$
	private static final String MARKER_ATT_KEY = "org.eclipse.ui.internal.registry.MarkerImageProviderRegistry";//$NON-NLS-1$
	private static final String TAG_PROVIDER = "imageprovider";//$NON-NLS-1$

	private ArrayList descriptors = new ArrayList();

	class Descriptor {
		String id;
		String markerType;
		String className;
		String imagePath;
		ImageDescriptor imageDescriptor;
		IConfigurationElement element;
		IPluginDescriptor pluginDescriptor;
		IMarkerImageProvider provider;
	}
/**
 * Initialize this new MarkerImageProviderRegistry.
 */
public MarkerImageProviderRegistry() {
	class MarkerImageReader extends IDERegistryReader {
		protected boolean readElement(IConfigurationElement element) {
			if (element.getName().equals(TAG_PROVIDER)) {
				addProvider(element);
				return true;
			}
			
			return false;
		}
		public void readRegistry() {
		    readRegistry(Platform.getPluginRegistry(), PlatformUI.PLUGIN_ID, IDEWorkbenchPlugin.PL_MARKER_IMAGE_PROVIDER);
		}
	}
	
	new MarkerImageReader().readRegistry();
}
/**
 * Creates a descriptor for the marker provider extension
 * and add it to the list of providers.
 */
public void addProvider(IConfigurationElement element) {
	Descriptor desc = new Descriptor();
	desc.element = element;
	desc.pluginDescriptor = element.getDeclaringExtension().getDeclaringPluginDescriptor();
	desc.id = element.getAttribute(ATT_ID);
	desc.markerType = element.getAttribute(ATT_MARKER_TYPE);
	desc.imagePath = element.getAttribute(ATT_ICON);
	desc.className = element.getAttribute(ATT_PROVIDER_CLASS);
	if(desc.imagePath != null) {
		desc.imageDescriptor = getImageDescriptor(desc);
	}
	if(desc.className == null) {
		//Don't need to keep these references.
		desc.element = null;
		desc.pluginDescriptor = null;
	}
	descriptors.add(desc);
}
/**
 * @see IWorkbenchAdapter#getImageDescriptor
 */
public ImageDescriptor getImageDescriptor(IMarker marker) {
	int size = descriptors.size();
	for (int i = 0; i < size; i++) {
		Descriptor desc = (Descriptor)descriptors.get(i);
		try {
			if(marker.isSubtypeOf(desc.markerType)) {
				if(desc.className != null) {
					if(desc.pluginDescriptor.isPluginActivated()) {
						//-- Get the image descriptor from the provider.
						//-- Save the image descriptor url as a persistable property, so a
						//image descriptor can be created without activating the plugin next
						//time the workbench is started.
						if(desc.provider == null)
							desc.provider = (IMarkerImageProvider)IDEWorkbenchPlugin.createExtension(
								desc.element, ATT_PROVIDER_CLASS);
						String path = desc.provider.getImagePath(marker);
						if(path != desc.imagePath) {
							desc.imagePath = path;
							desc.imageDescriptor = getImageDescriptor(desc);
							return desc.imageDescriptor;
						}
						return desc.imageDescriptor;
					} else {
						if(desc.imageDescriptor == null) {
							//Create a image descriptor to be used until the plugin gets activated.
							desc.imagePath = (String)marker.getAttribute(MARKER_ATT_KEY);
							desc.imageDescriptor = getImageDescriptor(desc);
						}
						return desc.imageDescriptor;
					}
				} else if(desc.imageDescriptor != null) {
					return desc.imageDescriptor;
				}
			}
		} catch (CoreException e) {
			IDEWorkbenchPlugin.getDefault().getLog().log(
				new Status(
					IStatus.ERROR,PlatformUI.PLUGIN_ID,0,
					"Exception creating image descriptor for: " +  desc.markerType,//$NON-NLS-1$
					e));
			return null;
		}
	}
	return null;
}
/**
 * Returns the image descriptor with the given relative path.
 */
ImageDescriptor getImageDescriptor(Descriptor desc) {
	try {
		URL installURL = desc.pluginDescriptor.getInstallURL();
		URL url = new URL(installURL, desc.imagePath);
		return ImageDescriptor.createFromURL(url);
	}
	catch (MalformedURLException e) {
		return null;
	}
}
}