using System;
using System.Linq;
using System.Windows;
using System.Windows.Controls;

using Wpf.Ui.Extend.Extensions;

namespace Wpf.Ui.Extend.Controls;
public class MultiTreeViewItem : TreeViewItem
{
    private MultiTreeView ParentMultiTreeView
    {
        //get { return ItemsControl.ItemsControlFromItemContainer(this) as MultiTreeView; }
        get { return this.FindParent<MultiTreeView>(); }
    }
    static MultiTreeViewItem()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(MultiTreeViewItem), new FrameworkPropertyMetadata(typeof(MultiTreeViewItem)));
        IsExpandedProperty.OverrideMetadata(typeof(MultiTreeViewItem), new FrameworkPropertyMetadata(true));
    }

    public bool? IsChecked
    {
        get { return (bool?)GetValue(IsCheckedProperty); }
        set { SetValue(IsCheckedProperty, value); }
    }

    public static readonly DependencyProperty IsCheckedProperty =
        DependencyProperty.Register(nameof(IsChecked), typeof(bool?), typeof(MultiTreeViewItem), new PropertyMetadata(false, new PropertyChangedCallback(OnIsCheckedChanged)));

    /// <summary>
    /// 获取项的容器。
    /// </summary>
    protected override DependencyObject GetContainerForItemOverride()
    {
        return new MultiTreeViewItem();
    }

    /// <summary>
    /// 确定项是否是其自己的容器。
    /// </summary>
    protected override bool IsItemItsOwnContainerOverride(object item)
    {
        return item is MultiTreeViewItem;
    }

    private static void OnIsCheckedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var currentChildren = d.FindVisualChildren<MultiTreeViewItem>();
        if (e.NewValue == e.OldValue)
        {
            return;
        }
        if (d is MultiTreeViewItem currentItem)
        {
            currentItem?.ParentMultiTreeView?.NotifyMultiTreeViewItemClicked(currentItem);
            foreach (var item in currentItem.FindVisualChildren<MultiTreeViewItem>())
            {
                if (e.NewValue != null)
                {
                    item.IsChecked = (bool)e.NewValue;
                }
            }
        }

        var parent = d.FindParent<MultiTreeViewItem>();
        if (parent != null)
        {
            var children = parent.FindVisualChildren<MultiTreeViewItem>();
            if (children.All(d => d.IsChecked == true))
            {
                parent.IsChecked = true;
            }
            else
            {
                parent.IsChecked = children.All(d => d.IsChecked == false) ? false : null;
            }
        }
       
    }
}