Wino-Mail/Wino.Mail/Behaviors/CreateMailNavigationItemBehavior.cs

using System.Collections.ObjectModel;
using Microsoft.Xaml.Interactivity;
using Windows.UI.Xaml;
using Wino.Core.Domain.Interfaces;
using Wino.Core.UWP.Controls;

namespace Wino.Behaviors;

public class CreateMailNavigationItemBehavior : Behavior<WinoNavigationViewItem>
{
    public IMenuItem SelectedMenuItem
    {
        get { return (IMenuItem)GetValue(SelectedMenuItemProperty); }
        set { SetValue(SelectedMenuItemProperty, value); }
    }

    public ObservableCollection<IMenuItem> MenuItems
    {
        get { return (ObservableCollection<IMenuItem>)GetValue(MenuItemsProperty); }
        set { SetValue(MenuItemsProperty, value); }
    }

    public static readonly DependencyProperty MenuItemsProperty = DependencyProperty.Register(nameof(MenuItems), typeof(ObservableCollection<IMenuItem>), typeof(CreateMailNavigationItemBehavior), new PropertyMetadata(null, OnMenuItemsChanged));
    public static readonly DependencyProperty SelectedMenuItemProperty = DependencyProperty.Register(nameof(SelectedMenuItem), typeof(IMenuItem), typeof(CreateMailNavigationItemBehavior), new PropertyMetadata(null, OnSelectedMenuItemChanged));

    public CreateMailNavigationItemBehavior()
    {

    }

    protected override void OnAttached()
    {
        base.OnAttached();
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
    }

    private static void OnMenuItemsChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
    {
        if (dependencyObject is CreateMailNavigationItemBehavior behavior)
        {
            if (dependencyPropertyChangedEventArgs.NewValue != null)
                behavior.RegisterMenuItemChanges();

            behavior.ManageAccounts();
        }
    }

    private void RegisterMenuItemChanges()
    {
        if (MenuItems != null)
        {
            MenuItems.CollectionChanged -= MenuCollectionUpdated;
            MenuItems.CollectionChanged += MenuCollectionUpdated;
        }
    }

    private void MenuCollectionUpdated(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        ManageAccounts();
    }

    private static void OnSelectedMenuItemChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
    {
        if (dependencyObject is CreateMailNavigationItemBehavior behavior)
        {
            behavior.ManageAccounts();
        }
    }

    private void ManageAccounts()
    {
        if (MenuItems == null) return;

        AssociatedObject.MenuItems.Clear();

        if (SelectedMenuItem == null)
        {
            // ??
        }
    }
}