using System.Collections.Generic;
using System.Windows.Controls;
using System.Windows.Media;

namespace System.Windows.Forms
{
    public partial class TreeView
    {
        private static class SelectItemHelper
        {
            public static void Select(CustomControls.TreeView tree, TreeNode newNode)
            {
                if (!tree.IsLoaded)
                    return;
                if (newNode == null)
                    return;

                var nodeDynasty = new List<TreeNode> { newNode };
                var parent = newNode.Parent;
                while (parent != null)
                {
                    nodeDynasty.Insert(0, parent);
                    parent = parent.Parent;
                }

                var currentParent = tree as ItemsControl;
                foreach (var node in nodeDynasty)
                {
                    // first try the easy way
                    var newParent = currentParent.ItemContainerGenerator.ContainerFromItem(node) as TreeViewItem;
                    if (newParent == null)
                    {
                        // if this failed, it's probably because of virtualization, and we will have to do it the hard way.
                        // see also the question at http://stackoverflow.com/q/183636/46635
                        var itemsPresenter = (ItemsPresenter)currentParent.Template.FindName("ItemsHost", currentParent);
                        if (itemsPresenter == null)
                            return;
                        var virtualizingPanel = (VirtualizingPanel)VisualTreeHelper.GetChild(itemsPresenter, 0);
                        var index = currentParent.Items.IndexOf(node);
                        if (index < 0)
                            return;
                        virtualizingPanel.BringIndexIntoViewPublic(index);
                        newParent = currentParent.ItemContainerGenerator.ContainerFromIndex(index) as TreeViewItem;
                    }

                    if (newParent == null)
                        return;
                    if (node == newNode)
                    {
                        newParent.IsSelected = true;
                        newParent.BringIntoView();
                        break;
                    }

                    newParent.IsExpanded = true;
                    currentParent = newParent;
                }
            }
        }

    }
}