using System.Runtime.InteropServices;

using WPFluent.Appearance;
using WPFluent.Interop;


// ReSharper disable once CheckNamespace
namespace WPFluent.Controls;

/// <summary>
/// Applies the chosen backdrop effect to the selected window.
/// </summary>
public static class WindowBackdrop
{
    private static SolidColorBrush GetFallbackBackgroundBrush()
    {
        return ApplicationThemeManager.GetAppTheme() switch
        {
            ApplicationTheme.HC1 => new SolidColorBrush(Color.FromArgb(0xFF, 0x2D, 0x32, 0x36)),
            ApplicationTheme.HC2 => new SolidColorBrush(Color.FromArgb(0xFF, 0x00, 0x00, 0x00)),
            ApplicationTheme.HCBlack => new SolidColorBrush(Color.FromArgb(0xFF, 0x20, 0x20, 0x20)),
            ApplicationTheme.HCWhite => new SolidColorBrush(Color.FromArgb(0xFF, 0x20, 0x20, 0x20)),
            ApplicationTheme.Unknown => new SolidColorBrush(Color.FromArgb(0xFF, 0xFF, 0xFA, 0xEF)),
            ApplicationTheme.Dark => new SolidColorBrush(Color.FromArgb(0xFF, 0x20, 0x20, 0x20)),
            ApplicationTheme.Light => new SolidColorBrush(Color.FromArgb(0xFF, 0xFA, 0xFA, 0xFA)),
            _ => new SolidColorBrush(Color.FromArgb(0xFF, 0xFA, 0xFA, 0xFA)),
        };
    }

    /*private static bool ApplyLegacyAcrylicBackdrop(IntPtr hWnd)
    {
        throw new NotImplementedException();
    }*/

    private static bool RestoreContentBackground(IntPtr hWnd)
    {
        if (hWnd == IntPtr.Zero)
        {
            return false;
        }

        if (!User32.IsWindow(hWnd))
        {
            return false;
        }

        var windowSource = HwndSource.FromHwnd(hWnd);

        // Restore client area background
        if (windowSource?.Handle != IntPtr.Zero && windowSource?.CompositionTarget != null)
        {
            windowSource.CompositionTarget.BackgroundColor = SystemColors.WindowColor;
        }

        if (windowSource?.RootVisual is System.Windows.Window window)
        {
            var backgroundBrush = window.Resources["ApplicationBackgroundBrush"];

            // Manual fallback
            if (backgroundBrush is not SolidColorBrush)
            {
                backgroundBrush = GetFallbackBackgroundBrush();
            }

            window.Background = (SolidColorBrush)backgroundBrush;
        }

        return true;
    }

    /// <summary>
    /// Tries to remove background from <see cref="Window"/> and it's composition area.
    /// </summary>
    /// <param name="window">Window to manipulate.</param>
    /// <returns><see langword="true"/> if operation was successful.</returns>
    public static bool RemoveBackground(System.Windows.Window? window)
    {
        if (window is null)
        {
            return false;
        }

        // Remove background from visual root
        window.SetCurrentValue(System.Windows.Controls.Control.BackgroundProperty, Brushes.Transparent);

        IntPtr windowHandle = new WindowInteropHelper(window).Handle;

        if (windowHandle == IntPtr.Zero)
        {
            return false;
        }

        var windowSource = HwndSource.FromHwnd(windowHandle);

        // Remove background from client area
        if (windowSource?.Handle != IntPtr.Zero && windowSource?.CompositionTarget != null)
        {
            windowSource.CompositionTarget.BackgroundColor = Colors.Transparent;
        }

        return true;
    }
}