using System.Reflection;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

using AntDesignWPF.Extensions;

namespace AntDesignWPF.Appearance;

/// <summary>
/// 允许通过交换包含动态资源的资源字典来管理应用程序主题。
/// </summary>
/// <example>
/// <code lang="csharp"> ThemeManager.ChangeAppTheme( ThemeMode.Light );</code> <code lang="csharp"> if
/// (ThemeManager.GetAppTheme() == ThemeMode.Dark) { ThemeManager.ChangeAppTheme(
/// ThemeMode.Light ); }</code> <code> ThemeManager.Changed += (theme, accent) => {
/// Debug.WriteLine($"Application theme changed to {theme.ToString()}"); };</code>
/// </example>
public class ThemeManager
{
    internal static string LibraryNamespace => Assembly.GetExecutingAssembly().GetName().Name;

    public static string ThemesDictionaryPath => $"pack://application:,,,/{LibraryNamespace};component/Themes/";

    private static ThemeMode _activeThemeMode = ThemeMode.Light;
    private static ThemePalette _activeThemePalette = ThemePalette.DaybreakBlue;
    public static event Action<ThemeMode>? ThemeModeChanged;
    public static event Action<ThemePalette>? ThemePaletteChanged;

    #region Animation


    private static Task AnimateBrushColorAsync(SolidColorBrush brush, Color toColor, int durationMs = 500)
    {
        if (brush.IsFrozen)
            return Task.CompletedTask; // 冻结的Brush无法动画，直接返回完成的Task

        var tcs = new TaskCompletionSource<bool>();
        var anim = new ColorAnimation
        {
            To = toColor,
            Duration = TimeSpan.FromMilliseconds(durationMs),
            EasingFunction = new CubicEase { EasingMode = EasingMode.EaseInOut },
            FillBehavior = FillBehavior.HoldEnd
        };

        // 在动画完成时标记任务完成
        anim.Completed += (s, e) => tcs.SetResult(true);
        brush.BeginAnimation(SolidColorBrush.ColorProperty, anim);

        return tcs.Task;
    }
    /// <summary>
    /// 动画过渡
    /// </summary>
    /// <param name="themeUri"></param>
    public void ChangeTheme(Uri themeUri)
    {
        // 1. 加载目标主题的资源字典，但先不合并
        ResourceDictionary newTheme = new ResourceDictionary { Source = themeUri };

        // 2. 遍历新主题中的画刷资源
        foreach (var key in newTheme.Keys)
        {
            // 只处理 SolidColorBrush
            if (newTheme[key] is SolidColorBrush newBrush)
            {
                // 3. 在当前的应用程序资源中找到同名的画刷
                var currentBrush = Application.Current.Resources[key] as SolidColorBrush;
                if (currentBrush != null)
                {
                    // 4. 创建颜色动画
                    var colorAnimation = new ColorAnimation
                    {
                        From = currentBrush.Color,
                        To = newBrush.Color,
                        Duration = new Duration(TimeSpan.FromMilliseconds(300)), // 动画时长
                        EasingFunction = new QuarticEase { EasingMode = EasingMode.EaseInOut } // 缓动函数，使动画更自然
                    };

                    // 5. 对当前画刷的 Color 属性应用动画
                    currentBrush.BeginAnimation(SolidColorBrush.ColorProperty, colorAnimation);
                }
            }
        }
    }
    #endregion

    /// <summary>
    /// 将资源应用于 <paramref name="frameworkElement"/>.
    /// </summary>
    public static void ApplyResourcesToElement(FrameworkElement frameworkElement)
    {
        if (frameworkElement.Resources.MergedDictionaries.Count <
            ThemeManager.Current.Resources.MergedDictionaries.Count)
        {
            foreach (var dictionary in ThemeManager.Current.Resources.MergedDictionaries)
            {
                frameworkElement.Resources.MergedDictionaries.Add(dictionary);
            }
        }
    }
    public static void SwitchThemePalette(ThemePalette themePalette)
    {
        if (themePalette == ThemePalette.DaybreakBlue)
        {
            return;
        }
    }
    /// <summary>
    /// 更改当前应用程序主题。
    /// </summary>
    /// <param name="themeMode">要设置的主题</param>
    /// <param name="backgroundEffect">是否应用自定义背景效果。</param>
    /// <param name="updateAccent">是否应更改颜色强调。</param>
    public static void SwitchThemeMode(ThemeMode themeMode)
    {
        if (themeMode == _activeThemeMode)
        {
            return;
        }

        ResourceDictionaryManager appDictionaries = new();

        var themeDictionaryName = themeMode switch
        {
            ThemeMode.Light => "Light",
            ThemeMode.Dark => "Dark",
            _ => throw new NotImplementedException(),
        };
        //ApplyThemeWithAnimation(applicationTheme);
        if (!appDictionaries.UpdateDictionary(
                "themes",
                new Uri($"{ThemesDictionaryPath}{themeDictionaryName}.xaml", UriKind.Absolute)))
        {
            return;
        }

        _activeThemeMode = themeMode;

        ThemeModeChanged?.Invoke(themeMode);
    }
  
    /// <summary>
    /// 获取当前设置的应用程序主题。
    /// </summary>
    /// <returns><see cref="ThemeMode.Unknow"/> if something goes wrong.</returns>
    public static ThemeMode GetAppTheme()
    {
        if (_activeThemeMode == ThemeMode.Light)
        {
            ResourceDictionaryManager appDictionaries = new();
            var themeDictionary = appDictionaries.LookupDictionary("themes");

            if (themeDictionary == null)
            {
                return ThemeMode.Light;
            }

            var themeUri = themeDictionary.Source.ToString();

            if (themeUri.Contains("light", StringComparison.OrdinalIgnoreCase))
            {
                _activeThemeMode = ThemeMode.Light;
            }

            if (themeUri.Contains("dark", StringComparison.OrdinalIgnoreCase))
            {
                _activeThemeMode = ThemeMode.Dark;
            }
        }

        return _activeThemeMode;
    }
    #region UiApplication

    private static ThemeManager? _themeManagerInstance;

    private readonly Application? application;

    private Window? mainWindow;

    private ResourceDictionary? resources;

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

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

        this.application = application;

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

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

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

    /// <summary>
    /// 获取或设置应用程序的资源。
    /// </summary>
    public object TryFindResource(object resourceKey) { return Resources[resourceKey]; }

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

            return _themeManagerInstance;
        }
    }


    /// <summary>
    /// 获取或设置应用程序的主窗口。
    /// </summary>
    public Window? MainWindow
    {
        get => application?.MainWindow ?? mainWindow;
        set
        {
            if (application != null)
            {
                application.MainWindow = value;
            }

            mainWindow = value;
        }
    }

    /// <summary>
    /// 获取或设置应用程序的资源。
    /// </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;
        }
    }
    #endregion
}