/*******************************************************************************
 * Copyright (c) 2011 Wind River Systems, Inc. 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:
 * Wind River Systems - initial API and implementation
 *******************************************************************************/
package org.eclipse.tcf.te.ui.views.editor;

import java.util.EventObject;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.tcf.te.runtime.events.ChangeEvent;
import org.eclipse.tcf.te.runtime.events.EventManager;
import org.eclipse.tcf.te.runtime.interfaces.IDisposable;
import org.eclipse.tcf.te.runtime.interfaces.properties.IPropertiesContainer;
import org.eclipse.tcf.te.ui.events.AbstractEventListener;
import org.eclipse.tcf.te.ui.views.activator.UIPlugin;
import org.eclipse.tcf.te.ui.views.interfaces.tracing.ITraceIds;
import org.eclipse.ui.forms.editor.IFormPage;

/**
 * Editor event listener implementation.
 * <p>
 * The event listener is registered by an editor instance for a given editor input
 * and is supposed to receive events for the editor input only.
 */
public final class EditorEventListener extends AbstractEventListener implements IDisposable {
	// Reference to the parent editor
	private final Editor editor;

	/**
     * Constructor.
     *
     * @param editor The parent editor. Must not be <code>null</code>.
     */
    public EditorEventListener(Editor editor) {
    	super();

    	Assert.isNotNull(editor);
    	this.editor = editor;

    	// Register the event listener if the editor input is a properties container
		Object node = editor.getEditorInput() != null ? editor.getEditorInput().getAdapter(Object.class) : null;
		if (node instanceof IPropertiesContainer) EventManager.getInstance().addEventListener(this, ChangeEvent.class, node);
    }

    /* (non-Javadoc)
     * @see org.eclipse.tcf.te.runtime.interfaces.IDisposable#dispose()
     */
    @Override
    public void dispose() {
    	EventManager.getInstance().removeEventListener(this);
    }

	/* (non-Javadoc)
	 * @see org.eclipse.tcf.te.runtime.interfaces.events.IEventListener#eventFired(java.util.EventObject)
	 */
	@Override
	public void eventFired(EventObject event) {
		// Ignore everything not being a change event
		if (!(event instanceof ChangeEvent)) return;

		ChangeEvent changeEvent = (ChangeEvent)event;

		if (UIPlugin.getTraceHandler().isSlotEnabled(0, ITraceIds.TRACE_EDITOR_EVENT_LISTENER)) {
			UIPlugin.getTraceHandler().trace("Entered eventFired(...). eventId='" + changeEvent.getEventId() + "'" //$NON-NLS-1$ //$NON-NLS-2$
												+ ", oldValue='" + changeEvent.getOldValue() + "'" //$NON-NLS-1$ //$NON-NLS-2$
												+ ", newValue='" + changeEvent.getNewValue() + "'", //$NON-NLS-1$ //$NON-NLS-2$
												0, ITraceIds.TRACE_EDITOR_EVENT_LISTENER,
												IStatus.INFO, this);
		}

		// Get the event source
		Object source = event.getSource();
		// Double check with the parent editors input object
		Object node = editor.getEditorInput() != null ? editor.getEditorInput().getAdapter(Object.class) : null;
		// If the editor input cannot be determined or it does not match the event source
		// --> return immediately
		if (node == null || !node.equals(source)) {
			if (UIPlugin.getTraceHandler().isSlotEnabled(0, ITraceIds.TRACE_EDITOR_EVENT_LISTENER)) {
				UIPlugin.getTraceHandler().trace("Dropping out of eventFired(...). Event source does not match editor input.", //$NON-NLS-1$
													0, ITraceIds.TRACE_EDITOR_EVENT_LISTENER,
													IStatus.WARNING, this);
			}

			return;
		}

		if ("editor.refreshTab".equals(changeEvent.getEventId())) { //$NON-NLS-1$
			editor.updatePageList();
		} else {
			// Update the active page content by calling IFormPage#setActive(boolean)
			Object page = editor.getSelectedPage();
			if (page instanceof IFormPage) {
				((IFormPage)page).setActive(((IFormPage)page).isActive());
			}

			// Update the editor part name
			editor.updatePartName();
		}
	}
}