/*******************************************************************************
 * Copyright (c) 2005, 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
 *     Brad Reynolds - bug 164653
 *     Ashley Cambrell - bug 198904
 *******************************************************************************/
module org.eclipse.jface.internal.databinding.swt.ListObservableValue;

import java.lang.all;

import org.eclipse.core.databinding.observable.Diffs;
import org.eclipse.jface.internal.databinding.provisional.swt.AbstractSWTObservableValue;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.List;
import org.eclipse.swt.widgets.Listener;

/**
 * @since 3.2
 * 
 */
public class ListObservableValue : AbstractSWTObservableValue {

    private final List list;

    private bool updating = false;

    private String currentValue;

    private Listener listener;

    /**
     * @param list
     */
    public this(List list) {
        super(list);
        this.list = list;
        this.currentValue = cast(String) doGetValue();

        if ((list.getStyle() & SWT.MULTI) > 0)
            throw new IllegalArgumentException(
                    "SWT.SINGLE support only for a List selection"); //$NON-NLS-1$

        listener = new class() Listener {

            public void handleEvent(Event event) {
                if (!updating) {
                    Object oldValue = currentValue;
                    currentValue = cast(String) doGetValue();
                    fireValueChange(Diffs.createValueDiff(oldValue,
                            currentValue));
                }
            }

        };
        list.addListener(SWT.Selection, listener);
    }

    public void doSetValue(Object value) {
        String oldValue = null;
        if (list.getSelection() !is null && list.getSelection().length > 0)
            oldValue = list.getSelection()[0];
        try {
            updating = true;
            String items[] = list.getItems();
            int index = -1;
            if (items !is null && value !is null) {
                for (int i = 0; i < items.length; i++) {
                    if (value.equals(items[i])) {
                        index = i;
                        break;
                    }
                }
                list.select(index); // -1 will not "unselect"
            }
            currentValue = cast(String) value;
        } finally {
            updating = false;
        }
        fireValueChange(Diffs.createValueDiff(oldValue, value));
    }

    public Object doGetValue() {
        int index = list.getSelectionIndex();
        if (index >= 0)
            return list.getItem(index);
        return null;
    }

    public Object getValueType() {
        return String.classinfo;
    }

    /*
     * (non-Javadoc)
     *
     * @see org.eclipse.core.databinding.observable.value.AbstractObservableValue#dispose()
     */
    public synchronized void dispose() {
        super.dispose();
        if (listener !is null && !list.isDisposed()) {
            list.removeListener(SWT.Selection, listener);
        }
    }
}