/*******************************************************************************
 * Copyright (c) 2004, 2010 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.jst.jsp.core.internal;

import org.eclipse.core.resources.ISaveContext;
import org.eclipse.core.resources.ISaveParticipant;
import org.eclipse.core.resources.ISavedState;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.IWorkspaceRunnable;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Plugin;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jst.jsp.core.internal.contentmodel.TaglibController;
import org.eclipse.jst.jsp.core.internal.contentproperties.JSPFContentPropertiesManager;
import org.eclipse.jst.jsp.core.internal.contenttype.DeploymentDescriptorPropertyCache;
import org.eclipse.jst.jsp.core.internal.java.JSPTranslatorPersister;
import org.eclipse.jst.jsp.core.internal.java.search.JSPIndexManager;
import org.eclipse.jst.jsp.core.internal.taglib.TaglibHelperManager;
import org.eclipse.jst.jsp.core.taglib.TaglibIndex;
import org.osgi.framework.BundleContext;

/**
 * The main plugin class to be used in the desktop.
 */
public class JSPCorePlugin extends Plugin {
	// The shared instance.
	private static JSPCorePlugin plugin;
	
	/** Save participant for this plugin */
	private ISaveParticipant fSaveParticipant;

	/**
	 * The constructor.
	 */
	public JSPCorePlugin() {
		super();
		plugin = this;
		fSaveParticipant = new SaveParticipant();
	}

	/**
	 * Returns the shared instance.
	 */
	public static JSPCorePlugin getDefault() {
		return plugin;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.runtime.Plugin#start(org.osgi.framework.BundleContext)
	 */
	public void start(BundleContext context) throws Exception {
		super.start(context);

		/*
		 * JSPIndexManager depends on TaglibController, so TaglibController
		 * should be started first
		 */
		TaglibIndex.startup();
		TaglibController.startup();

		// listen for classpath changes
		JavaCore.addElementChangedListener(TaglibHelperManager.getInstance());

		/*
		 * Restore save state and process any events that happened before
		 * plug-in loaded. Don't do it immediately since adding the save
		 * participant requires a lock on the workspace to compute the
		 * accumulated deltas, and if the tree is not already locked it
		 * becomes a blocking call.
		 */
		if (JSPTranslatorPersister.ACTIVATED) {
			Job persister = new Job(JSPCoreMessages.Initializing) {
				protected IStatus run(IProgressMonitor monitor) {
					final IWorkspace workspace = ResourcesPlugin.getWorkspace();
					try {
						workspace.run(new IWorkspaceRunnable() {
							public void run(IProgressMonitor monitor) throws CoreException {
								ISavedState savedState = null;
								try {
									savedState = workspace.addSaveParticipant(getBundle().getSymbolicName(), fSaveParticipant);
								}
								catch (CoreException e) {
									Logger.logException("Could not load previous save state", e);
								}
								if (savedState != null) {
									try {
										Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
									}
									finally {
										savedState.processResourceChangeEvents(JSPTranslatorPersister.getDefault());
									}
								}
							}
						}, monitor);
					}
					catch (CoreException e) {
						return e.getStatus();
					}
					finally {
						/*
						 * set up persister to listen to resource change
						 * events
						 */
						workspace.addResourceChangeListener(JSPTranslatorPersister.getDefault());
					}
					return Status.OK_STATUS;
				}
			};
			persister.setUser(false);
			persister.schedule(2000);
		}
		
		//init the JSP index
		JSPIndexManager.getInstance().initialize();

		// listen for resource changes to update content properties keys
		JSPFContentPropertiesManager.startup();

		DeploymentDescriptorPropertyCache.start();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.runtime.Plugin#stop(org.osgi.framework.BundleContext)
	 */
	public void stop(BundleContext context) throws Exception {
		DeploymentDescriptorPropertyCache.stop();

		/*
		 * stop listening for resource changes to update content properties
		 * keys
		 */
		JSPFContentPropertiesManager.shutdown();

		//remove the plugin save participant
		ResourcesPlugin.getWorkspace().removeSaveParticipant(plugin.getBundle().getSymbolicName());
		
		//remove the translator persister
		if(JSPTranslatorPersister.ACTIVATED) {
			ResourcesPlugin.getWorkspace().removeResourceChangeListener(JSPTranslatorPersister.getDefault());
		}
		
		// stop any indexing
		JSPIndexManager.getInstance().shutdown();

		// stop listening for classpath changes
		JavaCore.removeElementChangedListener(TaglibHelperManager.getInstance());

		// stop taglib controller
		TaglibController.shutdown();
		TaglibIndex.shutdown();

		super.stop(context);
	}
	
	/**
	 * Used so that all of the IResourceChangeEvents that occurred before
	 * this plugin loaded can be processed.
	 */
	private static class SaveParticipant implements ISaveParticipant {
		/**
		 * <p>Default constructor</p>
		 */
		protected SaveParticipant() {
		}
		
		/**
		 * @see org.eclipse.core.resources.ISaveParticipant#doneSaving(org.eclipse.core.resources.ISaveContext)
		 */
		public void doneSaving(ISaveContext context) {
			//ignore
		}
	
		/**
		 * @see org.eclipse.core.resources.ISaveParticipant#prepareToSave(org.eclipse.core.resources.ISaveContext)
		 */
		public void prepareToSave(ISaveContext context) throws CoreException {
			//ignore
		}
	
		/**
		 * @see org.eclipse.core.resources.ISaveParticipant#rollback(org.eclipse.core.resources.ISaveContext)
		 */
		public void rollback(ISaveContext context) {
			//ignore
		}
	
		/**
		 * @see org.eclipse.core.resources.ISaveParticipant#saving(org.eclipse.core.resources.ISaveContext)
		 */
		public void saving(ISaveContext context) throws CoreException {
			context.needDelta();
		}
	}
}