using WPFluent.Appearance;
using WPFluent.Extensions;
using WPFluent.Markup;


namespace WPFluent;

/// <summary>
/// 表示 UI 应用程序。
/// </summary>
public class UiApplication
{
    private static UiApplication? _uiApplication;

    private readonly Application? application;

    private Window? _mainWindow;

    private ResourceDictionary? _resources;

    /// <summary>
    /// 初始化 <see cref="UiApplication"/> 实例.
    /// </summary>
    public UiApplication(Application application)
    {
        if (application is null)
        {
            return;
        }

        if (!ApplicationHasResources(application))
        {
            return;
        }

        this.application = application;

        System.Diagnostics.Debug
            .WriteLine($"INFO | {typeof(UiApplication)} application is {this.application}", "WPFluent");
    }

    private static bool ApplicationHasResources(Application application)
    {
        return application
            .Resources.MergedDictionaries
            .Where(e => e.Source is not null)
            .Any(
                e => e.Source
                    .ToString()
                    .Contains(ApplicationThemeManager.LibraryNamespace, StringComparison.OrdinalIgnoreCase));
    }

    /// <summary>
    /// 将应用程序的 变为 shutdown 模式。
    /// </summary>
    public void Shutdown() { application?.Shutdown(); }

    /// <summary>
    /// Gets or sets the application's main window.
    /// </summary>
    public object TryFindResource(object resourceKey) { return Resources[resourceKey]; }

    /// <summary>
    /// 获取当前应用程序。
    /// </summary>
    public static UiApplication Current
    {
        get
        {
            _uiApplication ??= new UiApplication(Application.Current);

            return _uiApplication;
        }
    }

    /// <summary>
    /// Gets a value indicating whether the application is running outside of the desktop app context.
    /// </summary>
    public bool IsApplication => application is not null;

    /// <summary>
    /// Gets or sets the application's main window.
    /// </summary>
    public Window? MainWindow
    {
        get => application?.MainWindow ?? _mainWindow;
        set
        {
            if (application != null)
            {
                application.MainWindow = value;
            }

            _mainWindow = value;
        }
    }

    /// <summary>
    /// Gets or sets the application's resources.
    /// </summary>
    public ResourceDictionary Resources
    {
        get
        {
            if (_resources is null)
            {
                _resources = [];

                try
                {
                    var themesDictionary = new ThemesDictionary();
                    var controlsDictionary = new ControlsDictionary();
                    _resources.MergedDictionaries.Add(themesDictionary);
                    _resources.MergedDictionaries.Add(controlsDictionary);
                }
                catch
                {
                }
            }

            return application?.Resources ?? _resources;
        }
        set
        {
            if (application is not null)
            {
                application.Resources = value;
            }

            _resources = value;
        }
    }
}