/*******************************************************************************
 * Copyright (c) 2009 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
 *     Zend Technologies
 *******************************************************************************/
package org.eclipse.php.internal.ui.editor.contentassist;

import java.util.Timer;
import java.util.TimerTask;

import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.php.internal.core.PHPCoreConstants;
import org.eclipse.php.internal.core.PHPCorePlugin;
import org.eclipse.php.internal.ui.PHPUiPlugin;
import org.eclipse.php.internal.ui.editor.PHPStructuredEditor;
import org.eclipse.swt.custom.BusyIndicator;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.wst.sse.ui.internal.StructuredTextViewer;

public class AutoActivationTrigger implements ISelectionChangedListener {

	private StructuredTextViewer textViewer;

	private AutoActivationTrigger(StructuredTextViewer textViewer) {
		this.textViewer = textViewer;
	}

	public static void register(IDocument document) {
		StructuredTextViewer textViewer = null;
		IWorkbenchPage page = PHPUiPlugin.getActivePage();
		if (page != null) {
			IEditorPart editor = page.getActiveEditor();
			if (editor instanceof PHPStructuredEditor) {
				textViewer = ((PHPStructuredEditor) editor).getTextViewer();
			}
		}
		if (textViewer != null && textViewer.getDocument() == document) {
			textViewer.addSelectionChangedListener(new AutoActivationTrigger(textViewer));
		}
	}

	@Override
	public void selectionChanged(SelectionChangedEvent event) {
		textViewer.removeSelectionChangedListener(this);

		final long delay = Platform.getPreferencesService().getLong(PHPCorePlugin.ID,
				PHPCoreConstants.CODEASSIST_AUTOACTIVATION_DELAY, 200, null);
		new Timer("Temporary Completion Delay").schedule(new TimerTask() { //$NON-NLS-1$
			@Override
			public void run() {
				textViewer.getControl().getDisplay().asyncExec(new Runnable() {
					@Override
					public void run() {
						BusyIndicator.showWhile(textViewer.getControl().getDisplay(), new Runnable() {
							@Override
							public void run() {
								textViewer.doOperation(ISourceViewer.CONTENTASSIST_PROPOSALS);
							}
						});
					}
				});
			}
		}, delay);
	}
}