/*******************************************************************************
 * Copyright (c) 2006-2008 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
 *     Tom Schindl<tom.schindl@bestsolution.at> - bugfix in: 214355
 *     Matthew Hall - bugs 215531, 226765
 *******************************************************************************/

module org.eclipse.jface.databinding.viewers.ObservableListContentProvider;

import java.lang.all;

import java.util.Set;

import org.eclipse.core.databinding.observable.IObservableCollection;
import org.eclipse.core.databinding.observable.list.IListChangeListener;
import org.eclipse.core.databinding.observable.list.IObservableList;
import org.eclipse.core.databinding.observable.list.ListChangeEvent;
import org.eclipse.core.databinding.observable.list.ListDiffVisitor;
import org.eclipse.core.databinding.observable.set.IObservableSet;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.internal.databinding.viewers.ObservableCollectionContentProvider;
import org.eclipse.jface.internal.databinding.viewers.ViewerElementSet;
import org.eclipse.jface.viewers.AbstractListViewer;
import org.eclipse.jface.viewers.AbstractTableViewer;
import org.eclipse.jface.viewers.IStructuredContentProvider;
import org.eclipse.jface.viewers.Viewer;

/**
 * A {@link IStructuredContentProvider content provider} for
 * {@link AbstractTableViewer} or {@link AbstractListViewer} that provides
 * elements of an {@link IObservableList} when set as the viewer's input.
 * Objects of this class listen for changes to the observable list, and will
 * insert and remove viewer elements to reflect observed changes.
 * 
 * <p>
 * This class is not intended to be subclassed by clients.
 * 
 * @since 1.1
 */
public class ObservableListContentProvider :
        IStructuredContentProvider {
    private ObservableCollectionContentProvider impl;

    private static class Impl : ObservableCollectionContentProvider
            , IListChangeListener {
        protected void checkInput(Object input) {
            Assert
                    .isTrue(null !is cast(IObservableList)input,
                            "This content provider only works with input of type IObservableList"); //$NON-NLS-1$
        }

        protected void addCollectionChangeListener(
                IObservableCollection collection) {
            (cast(IObservableList) collection).addListChangeListener(this);
        }

        protected void removeCollectionChangeListener(
                IObservableCollection collection) {
            (cast(IObservableList) collection).removeListChangeListener(this);
        }

        public void handleListChange(ListChangeEvent event) {
            if (isViewerDisposed())
                return;
            final Set removals = ViewerElementSet.withComparer(comparer);

            event.diff.accept(new class() ListDiffVisitor {
                public void handleAdd(int index, Object element) {
                    knownElements.add(element);
                    viewerUpdater.insert(element, index);
                }

                public void handleRemove(int index, Object element) {
                    viewerUpdater.remove(element, index);
                    removals.add(element);
                }

                public void handleReplace(int index, Object oldElement,
                        Object newElement) {
                    knownElements.add(newElement);
                    viewerUpdater.replace(oldElement, newElement, index);
                    removals.add(oldElement);
                }

                public void handleMove(int oldIndex, int newIndex,
                        Object element) {
                    viewerUpdater.move(element, oldIndex, newIndex);
                }
            });

            // For each removed element, do not remove from known elements if
            // the element is still present elsewhere in the list.
            removals.removeAll(event.getObservableList());
            knownElements.removeAll(removals);
        }
    }

    /**
     * Constructs an ObservableListContentProvider
     */
    public this() {
        impl = new Impl();
    }

    public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
        impl.inputChanged(viewer, oldInput, newInput);
    }

    public Object[] getElements(Object inputElement) {
        return impl.getElements(inputElement);
    }

    public void dispose() {
        impl.dispose();
    }

    /**
     * Returns the set of elements known to this content provider. Label
     * providers may track this set if they need to be notified about additions
     * before the viewer sees the added element, and notified about removals
     * after the element was removed from the viewer. This is intended for use
     * by label providers, as it will always return the items that need labels.
     * 
     * @return readableSet of items that will need labels
     */
    public IObservableSet getKnownElements() {
        return impl.getKnownElements();
    }
}