/*******************************************************************************
 * Copyright (c) 2011, 2016 Ericsson 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:
 *     Marc Khouzam (Ericsson) - initial API and implementation
 *     Marc Khouzam (Ericsson) - Add support for multi-attach (Bug 293679)
 *******************************************************************************/
package org.eclipse.cdt.dsf.gdb.internal.ui.launching;

import java.util.Arrays;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.viewers.ILabelProvider;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.dialogs.ISelectionStatusValidator;
import org.eclipse.ui.dialogs.TwoPaneElementSelector;

/**
 * Process prompter that allows the user to select one or more entries
 * in the top pane.  Those entries are displayed in the bottom pane.
 * No selection is allowed in the bottom pane.  The result returned
 * is the list of all selections of the top pane (shown in the bottom
 * pane).
 */
public class ProcessPrompterDialog extends TwoPaneElementSelector {

	public ProcessPrompterDialog(Shell parent, ILabelProvider elementRenderer,
			ILabelProvider qualifierRenderer) {
		super(parent, elementRenderer, qualifierRenderer);
	}
	
	/*
	 * The result should be every selected element.
	 */
    @Override
    protected void computeResult() {
        setResult(Arrays.asList(getSelectedElements()));
    }

    /*
     * Disable the ability to select items in the bottom pane.
     */
    @Override
    protected Table createLowerList(Composite parent) {
    	final Table list = super.createLowerList(parent);
    	
    	// First remove listeners such as the double click.
    	// We don't want the user to trigger the action by
    	// double-clicking on the bottom pane.
    	int[] events = { SWT.Selection, SWT.MouseDoubleClick };
    	for (int event : events) {
    		Listener[] selectionListeners = list.getListeners(event);
    		for (Listener listener : selectionListeners) {
    			list.removeListener(event, listener);
    		}
    	}
    	
    	// Now add a listener to prevent selection
    	list.addListener(SWT.EraseItem, new Listener() {
            @Override
    	    public void handleEvent(Event event) {
    	    	if ((event.detail & SWT.SELECTED) != 0) {
    	    		event.detail &= ~SWT.SELECTED;
    	    		// Removing the SELECTED event did not work properly.
    	    		// The foreground text became invisible.
    	    		// Let's simply deselect everything
    	    		list.deselectAll();
    	    	}
    	    }
    	});
    	return list;
    }

    /*
     * Allow a double-click to work without any selection
     * in the bottom list.
     */
    @Override
	protected void handleDefaultSelected() {
        if (validateCurrentSelection()) {
			buttonPressed(IDialogConstants.OK_ID);
		}
    }
    
	/**
	 * Validate only upper selected elements. Lower list is always disabled.
	 * 
	 * @see #createLowerList(Composite)
	 */
	@Override
	protected boolean validateCurrentSelection() {
		ISelectionStatusValidator validator = getValidator();
		Object[] elements = getSelectedElements();

		if (elements.length > 0) {
			IStatus status;
			if (validator != null) {
				status = validator.validate(elements);
			} else {
				status = new Status(IStatus.OK, PlatformUI.PLUGIN_ID, IStatus.OK, "", //$NON-NLS-1$
						null);
			}
			updateStatus(status);
			return status.isOK();
		}

		return super.validateCurrentSelection();
	}
}