Wino-Mail/Wino.Mail/Dialogs/AccountReorderDialog.xaml.cs

using System.Collections.ObjectModel;
using System.Linq;
using Microsoft.Extensions.DependencyInjection;
using Windows.UI.Xaml.Controls;
using Wino.Core.Domain.Interfaces;

namespace Wino.Dialogs
{
    public sealed partial class AccountReorderDialog : ContentDialog
    {
        public ObservableCollection<IAccountProviderDetailViewModel> Accounts { get; }

        private int count;
        private bool isOrdering = false;

        private readonly IAccountService _accountService = App.Current.Services.GetService<IAccountService>();

        public AccountReorderDialog(ObservableCollection<IAccountProviderDetailViewModel> accounts)
        {
            Accounts = accounts;

            count = accounts.Count;

            InitializeComponent();
        }

        private void DialogOpened(ContentDialog sender, ContentDialogOpenedEventArgs args)
        {
            Accounts.CollectionChanged -= AccountsChanged;
            Accounts.CollectionChanged += AccountsChanged;
        }

        private void DialogClosed(ContentDialog sender, ContentDialogClosedEventArgs args) => Accounts.CollectionChanged -= AccountsChanged;

        private async void AccountsChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
            if (count - 1 == Accounts.Count)
                isOrdering = true;

            if (count == Accounts.Count && isOrdering)
            {
                // Order is completed. Apply changes.

                var dict = Accounts.ToDictionary(a => a.StartupEntityId, a => Accounts.IndexOf(a));

                await _accountService.UpdateAccountOrdersAsync(dict);

                isOrdering = false;
            }
        }
    }
}