using System.Windows;
using System.Windows.Media;
using Microsoft.Win32;
using MediaColor = System.Windows.Media.Color;

namespace TaskbarLauncher.Services;

public static class ThemeService
{
    private const string PersonalizeKey = @"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize";
    private const string DwmKey = @"Software\Microsoft\Windows\DWM";

    public static void Apply()
    {
        bool isLight = IsLightTheme();
        MediaColor accent = GetAccentColor();
        MediaColor window = isLight ? MediaColor.FromRgb(0xF7, 0xF7, 0xF7) : MediaColor.FromRgb(0x20, 0x20, 0x20);
        MediaColor surface = isLight ? System.Windows.Media.Colors.White : MediaColor.FromRgb(0x2B, 0x2B, 0x2B);
        MediaColor control = isLight ? MediaColor.FromRgb(0xF3, 0xF3, 0xF3) : MediaColor.FromRgb(0x33, 0x33, 0x33);
        MediaColor hover = isLight ? MediaColor.FromRgb(0xEA, 0xF3, 0xFF) : MediaColor.FromRgb(0x3B, 0x4A, 0x5C);
        MediaColor text = isLight ? MediaColor.FromRgb(0x1A, 0x1A, 0x1A) : MediaColor.FromRgb(0xF3, 0xF3, 0xF3);
        MediaColor muted = isLight ? MediaColor.FromRgb(0x66, 0x66, 0x66) : MediaColor.FromRgb(0xB8, 0xB8, 0xB8);
        MediaColor border = isLight ? MediaColor.FromRgb(0xC8, 0xC8, 0xC8) : MediaColor.FromRgb(0x55, 0x55, 0x55);
        MediaColor selectedText = IsDark(accent) ? System.Windows.Media.Colors.White : System.Windows.Media.Colors.Black;

        SetBrush("AppWindowBrush", window);
        SetBrush("AppSurfaceBrush", surface);
        SetBrush("AppControlBrush", control);
        SetBrush("AppControlHoverBrush", hover);
        SetBrush("AppTextBrush", text);
        SetBrush("AppMutedTextBrush", muted);
        SetBrush("AppBorderBrush", border);
        SetBrush("AppAccentBrush", accent);
        SetBrush("AppSelectedTextBrush", selectedText);

        SetBrush(System.Windows.SystemColors.WindowBrushKey, surface);
        SetBrush(System.Windows.SystemColors.WindowTextBrushKey, text);
        SetBrush(System.Windows.SystemColors.ControlBrushKey, control);
        SetBrush(System.Windows.SystemColors.ControlTextBrushKey, text);
        SetBrush(System.Windows.SystemColors.ControlDarkBrushKey, border);
        SetBrush(System.Windows.SystemColors.HighlightBrushKey, accent);
        SetBrush(System.Windows.SystemColors.HighlightTextBrushKey, selectedText);
    }

    private static bool IsLightTheme()
    {
        object? value = Registry.CurrentUser.OpenSubKey(PersonalizeKey)?.GetValue("AppsUseLightTheme");
        return value is null || Convert.ToInt32(value) != 0;
    }

    private static MediaColor GetAccentColor()
    {
        object? value = Registry.CurrentUser.OpenSubKey(DwmKey)?.GetValue("AccentColor");
        if (value is int colorValue)
        {
            byte r = (byte)(colorValue & 0xFF);
            byte g = (byte)((colorValue >> 8) & 0xFF);
            byte b = (byte)((colorValue >> 16) & 0xFF);
            return MediaColor.FromRgb(r, g, b);
        }

        return MediaColor.FromRgb(0x00, 0x78, 0xD4);
    }

    private static void SetBrush(string key, MediaColor color)
    {
        SolidColorBrush brush = new(color);
        brush.Freeze();
        System.Windows.Application.Current.Resources[key] = brush;
    }

    private static void SetBrush(ResourceKey key, MediaColor color)
    {
        SolidColorBrush brush = new(color);
        brush.Freeze();
        System.Windows.Application.Current.Resources[key] = brush;
    }

    private static bool IsDark(MediaColor color)
    {
        double luminance = (0.299 * color.R) + (0.587 * color.G) + (0.114 * color.B);
        return luminance < 140;
    }
}