using System.Windows.Shell;

using WPFluent.Appearance;

namespace WPFluent.Controls;

/// <summary>
/// If you use <see cref="WindowChrome"/> to extend the UI elements to the non-client area, you can include this
/// container in the template of <see cref="Window"/> so that the content inside automatically fills the client area.
/// Using this container can let you get rid of various margin adaptations done in Setter/Trigger of the style of <see
/// cref="Window"/> when the window state changes.
/// </summary>
/// <example>
/// <code lang="xml"> &lt;Style x:Key="MyWindowCustomStyle" BasedOn="{StaticResource {x:Type Window}}"
/// TargetType="{x:Type controls:FluentWindow}"&gt; &lt;Setter Property="Template" &gt; &lt;Setter.Value&gt;
/// &lt;ControlTemplate TargetType="{x:Type Window}"&gt; &lt;AdornerDecorator&gt; &lt;controls:ClientAreaBorder
/// Background="{TemplateBinding Background}" ControlBorderBrush="{TemplateBinding ControlBorderBrush}"
/// BorderThickness="{TemplateBinding BorderThickness}"&gt; &lt;ContentPresenter x:Name="ContentPresenter" /&gt;
/// &lt;/controls:ClientAreaBorder&gt; &lt;/AdornerDecorator&gt; &lt;/ControlTemplate&gt; &lt;/Setter.Value&gt;
/// &lt;/Setter&gt; &lt;/Style&gt;</code>
/// </example>
public class ClientAreaBorder : System.Windows.Controls.Border/*, IThemeControl*/
{
    /*private const int SM_CXFRAME = 32;
    private const int SM_CYFRAME = 33;
    private const int SM_CXPADDEDBORDER = 92;*/
    private static Thickness? _resizeFrameBorderThickness;
    private static Thickness? _windowChromeNonClientFrameThickness;
    //private bool borderBrushApplied = false;
    private System.Windows.Window? _oldWindow;

    //public ClientAreaBorder()
    //{
    //    ApplicationTheme = Appearance.ThemeManager.GetAppTheme();
    //    Appearance.ThemeManager.Changed += OnThemeChanged;
    //}

    //private void ApplyDefaultWindowBorder()
    //{
    //    if (_oldWindow == null)
    //    {
    //        return;
    //    }

    //    borderBrushApplied = true;

    //    // SystemParameters.WindowGlassBrush
    //    Color borderColor =
    //        ApplicationTheme == ThemeType.Light
    //        ? Color.FromArgb(0xFF, 0x7A, 0x7A, 0x7A)
    //        : Color.FromArgb(0xFF, 0x3A, 0x3A, 0x3A);
    //    _oldWindow.SetCurrentValue(
    //        System.Windows.Controls.Control.BorderBrushProperty,
    //        new SolidColorBrush(borderColor));
    //    _oldWindow.SetCurrentValue(System.Windows.Controls.Control.BorderThicknessProperty, new Thickness(1));
    //}

    //private void OnThemeChanged(ThemeType currentApplicationTheme, Color systemAccent)
    //{
    //    ApplicationTheme = currentApplicationTheme;

    //    if (!borderBrushApplied || _oldWindow == null)
    //    {
    //        return;
    //    }

    //    ApplyDefaultWindowBorder();
    //}

    private void OnWindowClosing(object? sender, CancelEventArgs e)
    {
        //Appearance.ThemeManager.Changed -= OnThemeChanged;
        if (_oldWindow != null)
        {
            _oldWindow.Closing -= OnWindowClosing;
        }
    }

    private void OnWindowStateChanged(object? sender, EventArgs e)
    {
        if (sender is not System.Windows.Window window)
        {
            return;
        }

        Thickness padding =
            window.WindowState == WindowState.Maximized ? WindowChromeNonClientFrameThickness : default;
        SetCurrentValue(PaddingProperty, padding);
    }

    /// <inheritdoc/>
    protected override void OnVisualParentChanged(DependencyObject oldParent)
    {
        base.OnVisualParentChanged(oldParent);

        if (_oldWindow is { } oldWindow)
        {
            oldWindow.StateChanged -= OnWindowStateChanged;
            oldWindow.Closing -= OnWindowClosing;
        }

        var newWindow = System.Windows.Window.GetWindow(this);

        if (newWindow is not null)
        {
            newWindow.StateChanged -= OnWindowStateChanged; // Unsafe
            newWindow.StateChanged += OnWindowStateChanged;
            newWindow.Closing += OnWindowClosing;
        }

        _oldWindow = newWindow;

        //ApplyDefaultWindowBorder();
    }

    //public ThemeType ApplicationTheme { get; set; } = ThemeType.Unknow;

    /// <summary>
    /// Gets the system <see cref="User32.SM.CXFRAME"/> and <see cref="User32.SM.CYFRAME"/> values in WPF units.
    /// </summary>
    public static Thickness ResizeFrameBorderThickness => _resizeFrameBorderThickness ??= new Thickness(
        SystemParameters.ResizeFrameVerticalBorderWidth,
        SystemParameters.ResizeFrameHorizontalBorderHeight,
        SystemParameters.ResizeFrameVerticalBorderWidth,
        SystemParameters.ResizeFrameHorizontalBorderHeight);

    /// <summary>
    /// Gets the thickness of the window's non-client frame used for maximizing the window with a custom chrome.
    /// </summary>
    /// <remarks>
    /// If you use a <see cref="WindowChrome"/> to extend the client area of a window to the non-client area, you need
    /// to handle the edge margin issue when the window is maximized. Use this property to get the correct margin value
    /// when the window is maximized, so that when the window is maximized, the client area can completely cover the
    /// screen client area by no less than a single pixel at any DPI. The<see cref="User32.GetSystemMetrics"/> method
    /// cannot obtain this value directly.
    /// </remarks>
    public Thickness WindowChromeNonClientFrameThickness => _windowChromeNonClientFrameThickness ??= new Thickness(
        ClientAreaBorder.ResizeFrameBorderThickness.Left,
        ClientAreaBorder.ResizeFrameBorderThickness.Top,
        ClientAreaBorder.ResizeFrameBorderThickness.Right,
        ClientAreaBorder.ResizeFrameBorderThickness.Bottom);
}