/*******************************************************************************
 * Copyright (c) 2000, 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.ui.views.tasklist;

import org.eclipse.core.resources.IMarker;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.window.Window;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.internal.views.tasklist.TaskListMessages;

/**
 * This action creates a new task. If a resource is currently
 * present at the tasklist's input, this task will be
 * associated with it. If the tasklist is currently
 * observing all the markers in the workbench, the task
 * will not be associated with any resource.
 * <p>The newly created task will have low priority,
 * fixed description text and will not be subject to
 * sorting or filtering until its desciprion is being
 * changed for the first time. For this reason, new
 * tasks remain at the top of the task list
 * until modified. It is possible that the newly
 * created task dissapears after that if its
 * type or some other property causes it to
 * be filtered out.
 */
class NewTaskAction extends TaskAction {

    /**
     * Creates the action.
     * 
     * @param tasklist the task list
     * @param id the id
     */
    public NewTaskAction(TaskList tasklist, String id) {
        super(tasklist, id);
        PlatformUI.getWorkbench().getHelpSystem().setHelp(this,
				ITaskListHelpContextIds.NEW_TASK_ACTION);
    }

    /**
     * Opens the new task dialog and shows the newly created task when done.
     * The new task is created on the currently selected resource.
     */
    public void run() {
        TaskPropertiesDialog dialog = new TaskPropertiesDialog(getShell());
        dialog.setResource(getTaskList().getResource());
        int result = dialog.open();
        if (result == Window.OK) {
            showMarker(dialog.getMarker());
        }
    }

    /**
     * Show the newly created marker.
     */
    private void showMarker(final IMarker marker) {
        if (marker == null) {
            return;
        }
        if (getTaskList().shouldShow(marker)) {
            // Need to do this in an asyncExec, even though we're in the UI thread here,
            // since the task list updates itself with the addition in an asyncExec,
            // which hasn't been processed yet.
            getShell().getDisplay().asyncExec(new Runnable() {
                public void run() {
                    getTaskList().setSelection(new StructuredSelection(marker),
                            true);
                }
            });
        } else {
            MessageDialog.openInformation(getShell(), TaskListMessages.NewTask_notShownTitle, 
                    TaskListMessages.NewTask_notShownMsg); 
        }
    }
}