/*******************************************************************************
 * Copyright (c) 2008 Matthew Hall 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:
 *     Matthew Hall - initial API and implementation (bug 226765)
 ******************************************************************************/

module org.eclipse.jface.internal.databinding.viewers.ViewerUpdater;

import java.lang.all;

import org.eclipse.jface.util.Util;
import org.eclipse.jface.viewers.IElementComparer;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.StructuredViewer;

/**
 * NON-API - An interface for updating a viewer's elements.
 * 
 * @since 1.2
 */
public abstract class ViewerUpdater {
    private final StructuredViewer viewer;

    /**
     * Constructs a ViewerUpdater for updating the specified viewer.
     * 
     * @param viewer
     *            the viewer which will be updated through this instance.
     */
    protected this(StructuredViewer viewer) {
        this.viewer = viewer;
    }

    /**
     * Insert the element into the viewer at the specified position.
     * 
     * @param element
     *            the element to add
     * @param position
     *            the position of the element
     */
    public abstract void insert(Object element, int position);

    /**
     * Remove the element from the viewer
     * 
     * @param element
     *            the element to remove
     * @param position
     *            the position of the element
     */
    public abstract void remove(Object element, int position);

    /**
     * Replace the specified element at the given position with the new element.
     * 
     * @param oldElement
     *            the element being replaced
     * @param newElement
     *            the element that replaces <code>oldElement</code>
     * @param position
     *            the position of the element being replaced.
     */
    public void replace(Object oldElement, Object newElement, int position) {
        remove(oldElement, position);
        insert(newElement, position);
    }

    /**
     * Moves the specified element from the specified old position to the
     * specified new position. No action is taken if the viewer has a sorter or
     * filter(s).
     * 
     * @param element
     *            the element being moved
     * @param oldPosition
     *            the position of the element before it is moved
     * @param newPosition
     *            the position of the element after it is moved
     */
    public void move(Object element, int oldPosition, int newPosition) {
        if (viewer.getComparator() is null && viewer.getFilters().length is 0) {
            IStructuredSelection selection = cast(IStructuredSelection) viewer
                    .getSelection();

            remove(element, oldPosition);
            insert(element, newPosition);

            // Preserve selection
            if (!selection.isEmpty()) {
                IElementComparer comparer = viewer.getComparer();
                Object[] selectedElements = selection.toArray();
                for (int i = 0; i < selectedElements.length; i++) {
                    if (comparer is null ? Util.equals(element,
                            selectedElements[i]) : comparer.equals(element,
                            selectedElements[i])) {
                        viewer.setSelection(selection);
                        break;
                    }
                }
            }
        }
    }

    /**
     * Adds the elements to the viewer.
     * 
     * @param elements
     *            the elements to add
     */
    public abstract void add(Object[] elements);

    /**
     * Removes the elements from the viewer
     * 
     * @param elements
     *            the elements to remove
     */
    public abstract void remove(Object[] elements);
}