using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Threading;
using ActiproSoftware.Windows.Controls.Docking;

namespace JD.Guinness.WPF.Module
{
    public sealed class ItemFocuser
    {
        private event Action<object> GoToItemAsked;

        public DelegateCommand<object> GoToItemCommand { get; }

        public ItemFocuser()
        {
            GoToItemCommand = new DelegateCommand<object>(OnGoToItem, i => i != null);
        }

        private void OnGoToItem(object item) => GoToItemAsked?.Invoke(item);

        private void TryShowWindow(FrameworkElement element)
        {
            while (element != null)
            {
                element = element.Parent as FrameworkElement;

                if (element is ToolWindow window)
                {
                    window.Activate(true);
                    // wait for ui display
                    element.Dispatcher.Invoke(new Action(() => { }), DispatcherPriority.ContextIdle, null);
                    break;
                }
            }
        }

        private void TryGoTo<T>(DataGrid dataGrid, object item)
        {
            if (item is T t)
            {
                TryShowWindow(dataGrid);
                dataGrid.ScrollIntoView(t);

                if (dataGrid.ItemContainerGenerator.ContainerFromItem(t) is DataGridRow row)
                {
                    dataGrid.SelectedItem = t;
                    // simulate keyboard focus so the element is properly selected
                    row.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
                }
            }
        }

        private void TryGoTo<T>(TabControl tabControl, object item)
        {
            if (item is T t)
            {
                TryShowWindow(tabControl);
                tabControl.SelectedItem = item;
            }
        }

        public void Subscribe<T>(DataGrid dataGrid) => GoToItemAsked += i => TryGoTo<T>(dataGrid, i);

        public void Subscribe<T>(TabControl tabControl) => GoToItemAsked += i => TryGoTo<T>(tabControl, i);

        public void SubscribeWindow<T>(FrameworkElement element) => GoToItemAsked += i => { if (i is T) TryShowWindow(element); };
    }
}