using WPFluent.Extensions;

using System;

using System.Linq;


namespace WPFluent.Controls;

public class MultiTreeViewItem : System.Windows.Controls.TreeViewItem
{
    public static readonly DependencyProperty IsCheckedProperty =
        DependencyProperty.Register(
        nameof(IsChecked),
        typeof(bool?),
        typeof(MultiTreeViewItem),
        new PropertyMetadata(false, new PropertyChangedCallback(OnIsCheckedChanged)));

    static MultiTreeViewItem()
    {
        DefaultStyleKeyProperty.OverrideMetadata(
            typeof(MultiTreeViewItem),
            new FrameworkPropertyMetadata(typeof(MultiTreeViewItem)));
        IsExpandedProperty.OverrideMetadata(typeof(MultiTreeViewItem), new FrameworkPropertyMetadata(true));
    }

    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;
            }
        }
    }

    private MultiTreeView ParentMultiTreeView
    {
        //get { return ItemsControl.ItemsControlFromItemContainer(this) as MultiTreeView; }
        get { return this.FindParent<MultiTreeView>(); }
    }

    /// <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; }

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