/*******************************************************************************
 * Copyright (c) 2007, 2008 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.ui.internal.views.markers;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.operations.IUndoableOperation;
import org.eclipse.core.resources.IMarker;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.osgi.util.NLS;
import org.eclipse.ui.ide.undo.DeleteMarkersOperation;
import org.eclipse.ui.ide.undo.WorkspaceUndoUtil;
import org.eclipse.ui.views.markers.MarkerItem;
import org.eclipse.ui.views.markers.MarkerViewHandler;
import org.eclipse.ui.views.markers.internal.MarkerMessages;

/**
 * DeleteCompletedHandler is the handler for the deletion of completed
 * tasks.
 * @since 3.4
 *
 */
public class DeleteCompletedHandler extends MarkerViewHandler {

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.IHandler#execute(org.eclipse.core.commands.ExecutionEvent)
	 */
	public Object execute(ExecutionEvent event) {

		ExtendedMarkersView view = getView(event);
		if (view == null)
			return this;

		final List completed = getCompletedTasks(view);
		// Check if there is anything to do
		if (completed.size() == 0) {
			MessageDialog.openInformation(view.getSite().getShell(),
					MarkerMessages.deleteCompletedTasks_dialogTitle,
					MarkerMessages.deleteCompletedTasks_noneCompleted);
			return this;
		}
		String message;
		if (completed.size() == 1) {
			message = MarkerMessages.deleteCompletedTasks_permanentSingular;
		} else {
			message = NLS.bind(
					MarkerMessages.deleteCompletedTasks_permanentPlural, String
							.valueOf(completed.size()));
		}
		// Verify.
		if (!MessageDialog.openConfirm(view.getSite().getShell(),
				MarkerMessages.deleteCompletedTasks_dialogTitle, message)) {
			return view;
		}

		IMarker[] markers = new IMarker[completed.size()];
		completed.toArray(markers);

		IUndoableOperation op = new DeleteMarkersOperation(markers,
				MarkerMessages.deleteCompletedAction_title);
		execute(op, MarkerMessages.deleteCompletedTasks_errorMessage, null,
				WorkspaceUndoUtil.getUIInfoAdapter(view.getSite().getShell()));
		
		return this;

	}

	/**
	 * Get the list of completed tasks from the view.
	 * 
	 * @param view
	 * @return List of {@link IMarker}
	 */
	private List getCompletedTasks(ExtendedMarkersView view) {

		List completed = new ArrayList();
		MarkerItem[] items = view.getAllConcreteItems();

		for (int i = 0; i < items.length; i++) {
			MarkerItem markerItem = items[i];
			if (markerItem.getAttributeValue(IMarker.DONE, false)
					&& markerItem.getMarker() != null) {
				completed.add(markerItem.getMarker());
			}
		}

		return completed;
	}

}