/*******************************************************************************
 * Copyright (c) 2007-2008 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 207858)
 *     Matthew Hall - bug 226765
 *******************************************************************************/

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

import java.lang.all;

import java.util.Iterator;
import java.util.Set;

import org.eclipse.core.databinding.observable.IObservableCollection;
import org.eclipse.core.databinding.observable.IObservablesListener;
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.masterdetail.IObservableFactory;
import org.eclipse.core.databinding.observable.set.IObservableSet;
import org.eclipse.jface.internal.databinding.viewers.ObservableCollectionTreeContentProvider;
import org.eclipse.jface.internal.databinding.viewers.ViewerElementSet;
import org.eclipse.jface.viewers.AbstractTreeViewer;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.Viewer;

/**
 * An {@link ITreeContentProvider} for use with an {@link AbstractTreeViewer},
 * which uses the provided {@link IObservableFactory list factory} to obtain the
 * elements of a tree. Object of this class listen for changes to each
 * {@link IObservableList} created by the factory, and will insert and remove
 * viewer elements to reflect the observed changes.
 * 
 * <p>
 * This class is not intended to be subclassed by clients.
 * 
 * @since 1.2
 */
public class ObservableListTreeContentProvider : ITreeContentProvider {
    private final ObservableCollectionTreeContentProvider impl;

    private static class Impl : ObservableCollectionTreeContentProvider {
        public this(IObservableFactory listFactory,
                TreeStructureAdvisor structureAdvisor) {
            super(listFactory, structureAdvisor);
        }

        private class ListChangeListener : IListChangeListener {
            final Object parentElement;

            public this(Object parentElement) {
                this.parentElement = parentElement;
            }

            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 child) {
                        // adds to known elements if new element
                        getOrCreateNode(child).addParent(parentElement);

                        viewerUpdater.insert(parentElement, child, index);
                    }

                    public void handleRemove(int index, Object child) {
                        viewerUpdater.remove(parentElement, child, index);

                        removals.add(child);
                    }

                    public void handleReplace(int index, Object oldChild,
                            Object newChild) {
                        getOrCreateNode(newChild).addParent(parentElement);

                        viewerUpdater.replace(parentElement, oldChild,
                                newChild, index);

                        removals.add(oldChild);
                    }

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

                // For each removed element, do not remove node's parent if the
                // element is still present elsewhere in the list.
                removals.removeAll(event.getObservableList());
                for (Iterator iterator = removals.iterator(); iterator
                        .hasNext();) {
                    TreeNode node = getExistingNode(iterator.next());
                    if (node !is null)
                        // removes from known elements if last parent
                        node.removeParent(parentElement);
                }
            }
        }

        protected IObservablesListener createCollectionChangeListener(
                Object parentElement) {
            return new ListChangeListener(parentElement);
        }

        protected void addCollectionChangeListener(
                IObservableCollection collection, IObservablesListener listener) {
            IObservableList list = cast(IObservableList) collection;
            IListChangeListener listListener = cast(IListChangeListener) listener;
            list.addListChangeListener(listListener);
        }

        protected void removeCollectionChangeListener(
                IObservableCollection collection, IObservablesListener listener) {
            IObservableList list = cast(IObservableList) collection;
            IListChangeListener listListener = cast(IListChangeListener) listener;
            list.removeListChangeListener(listListener);
        }
    }

    /**
     * Constructs an ObservableListTreeContentProvider using the given list
     * factory.
     * 
     * @param listFactory
     *            observable factory that produces an IObservableList of
     *            children for a given parent element. Observable lists created
     *            by this factory must be on the realm of the current display.
     * @param structureAdvisor
     *            an advisor that will be consulted from the implementations of
     *            the {@link #getParent(Object)} and
     *            {@link #hasChildren(Object)} methods, or <code>null</code>
     *            if no advisor is available. It is recommended that clients
     *            pass a non-null advisor if they can provide additional
     *            structural information about the tree.
     */
    public this(IObservableFactory listFactory,
            TreeStructureAdvisor structureAdvisor) {
        impl = new Impl(listFactory, structureAdvisor);
    }

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

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

    public bool hasChildren(Object element) {
        return impl.hasChildren(element);
    }

    public Object[] getChildren(Object parentElement) {
        return impl.getChildren(parentElement);
    }

    public Object getParent(Object element) {
        return impl.getParent(element);
    }

    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();
    }
}