/*******************************************************************************
 * Copyright (c) 2005 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.wst.sse.ui.internal.selection;

import org.eclipse.jface.action.IAction;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.swt.widgets.Event;
import org.eclipse.ui.IActionDelegate2;
import org.eclipse.ui.IEditorActionDelegate;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IViewActionDelegate;
import org.eclipse.ui.IViewPart;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.wst.sse.ui.internal.SSEUIMessages;

/**
 * Selection history action delegate. Keeps track of selection within editor.
 */
public class StructuredSelectHistoryActionDelegate implements IEditorActionDelegate, IActionDelegate2, IViewActionDelegate {
	private IEditorPart fEditor;
	private SelectionHistory fHistory;

	public void dispose() {
		fEditor = null;
		fHistory = null;
	}

	public void init(IAction action) {
		if (action != null) {
			action.setText(SSEUIMessages.StructureSelectHistory_label);
			action.setToolTipText(SSEUIMessages.StructureSelectHistory_tooltip);
			action.setDescription(SSEUIMessages.StructureSelectHistory_description);
		}
	}

	public void init(IViewPart view) {
		// do nothing
	}

	public void run(IAction action) {
		IRegion old = fHistory.getLast();
		if (old != null) {
			try {
				fHistory.ignoreSelectionChanges();
				if (fEditor instanceof ITextEditor)
					((ITextEditor) fEditor).selectAndReveal(old.getOffset(), old.getLength());
			}
			finally {
				fHistory.listenToSelectionChanges();
			}
		}
	}

	public void runWithEvent(IAction action, Event event) {
		run(action);
	}

	public void selectionChanged(IAction action, ISelection selection) {
		// do nothing
	}

	public void setActiveEditor(IAction action, IEditorPart targetEditor) {
		fEditor = targetEditor;
		if (fEditor != null)
			fHistory = (SelectionHistory) fEditor.getAdapter(SelectionHistory.class);
		else
			fHistory = null;
		if (fHistory != null) {
			fHistory.setHistoryAction(action);
		}
	}
}