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

namespace Sai.Toolkit.Core.Helpers;

public sealed record SingletonViewHelper<T>
    where T : Window, new()
{
    private static T instance;
    private static readonly object Padlock = new();

    private SingletonViewHelper() { }

    public static T GetInstance(out bool isNewCreate)
    {
        isNewCreate = false;
        //double-check locking
        if (instance == null)
        {
            isNewCreate = true;
            lock (Padlock)
            {
                instance ??= new T();
                instance.Closed += OnWindowClosed;
            }
        }
        return instance;
    }

    private static void OnWindowClosed(object sender, EventArgs e)
    {
        instance = null;
    }
}

public static class SingletonChildWindowManager
{
    private static readonly Dictionary<Type, Window> Windows = [];
    public static void ShowOrActivate<TWindow, TViewModel>(params object[] viewModelParams)
        where TWindow : Window, new()
        where TViewModel : class
    {
        var windowType = typeof(TWindow);
        if (Windows.TryGetValue(windowType, out var window) && window != null)
        {
            window.Activate();
        }
        else
        {
            //CloseAllWindowsExcept(windowType);
            Windows[windowType] = new TWindow();
            Windows[windowType].Closed += (sender, args) => Windows[windowType] = null;
            if (Windows[windowType].DataContext == null || Windows[windowType].DataContext is not TViewModel)
            {
                if (viewModelParams.Length == 0)
                {
                    Windows[windowType].DataContext = Activator.CreateInstance(typeof(TViewModel));
                }
                else
                {
                    Windows[windowType].DataContext = Activator.CreateInstance(typeof(TViewModel), viewModelParams);
                }
            }
            _ = new WindowInteropHelper(Windows[windowType]) { Owner = System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle };
            Windows[windowType].Show();
        }
    }
}