using System;
using System.Windows;
using System.Windows.Interop;


namespace Szmedi.Test
{
    public static class SingletonWindowManager
    {
        private static Window _currentWindow;

        public static void ShowOrActivate<TWindow, TViewModel>(params object[] viewModelParameters)
            where TWindow : Window, new()
            where TViewModel : class
        {
            if (_currentWindow == null || _currentWindow is not TWindow)
            {
                _currentWindow?.Close();
                _currentWindow = new TWindow();
                if (_currentWindow.DataContext == null || _currentWindow.DataContext is not TViewModel)
                {
                    if (viewModelParameters.Length == 0)
                    {
                        _currentWindow.DataContext = Activator.CreateInstance(typeof(TViewModel));
                    }
                    else
                    {
                        _currentWindow.DataContext = Activator.CreateInstance(typeof(TViewModel), viewModelParameters);
                    }
                }
                _currentWindow.Closed += (sender, args) => _currentWindow = null;
                _ = new WindowInteropHelper(_currentWindow) { Owner = System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle };
                _currentWindow.Show();
            }
            else
            {
                _currentWindow.Activate();
            }
        }
    }
}