using System;
using System.Runtime.InteropServices;
using System.Windows.Interop;
using System.Windows;
using Windows.Win32;
using Windows.Win32.Graphics.Dwm;
using Flow.Launcher.Infrastructure.UserSettings;

namespace Flow.Launcher.Infrastructure
{
    public static class Win32Helper
    {
        #region Blur Handling

        public static unsafe bool DWMSetBackdropForWindow(Window window, BackdropTypes backdrop)
        {
            var windowHelper = new WindowInteropHelper(window);
            windowHelper.EnsureHandle();

            var backdropType = backdrop switch
            {
                BackdropTypes.Acrylic => DWM_SYSTEMBACKDROP_TYPE.DWMSBT_TRANSIENTWINDOW,
                BackdropTypes.Mica => DWM_SYSTEMBACKDROP_TYPE.DWMSBT_MAINWINDOW,
                BackdropTypes.MicaAlt => DWM_SYSTEMBACKDROP_TYPE.DWMSBT_TABBEDWINDOW,
                _ => DWM_SYSTEMBACKDROP_TYPE.DWMSBT_AUTO
            };

            return PInvoke.DwmSetWindowAttribute(
                new(windowHelper.Handle),
                DWMWINDOWATTRIBUTE.DWMWA_SYSTEMBACKDROP_TYPE,
                &backdropType,
                (uint)Marshal.SizeOf<int>()).Succeeded;
        }

        public static unsafe bool DWMSetDarkModeForWindow(Window window, bool useDarkMode)
        {
            var windowHelper = new WindowInteropHelper(window);
            windowHelper.EnsureHandle();

            var darkMode = useDarkMode ? 1 : 0;

            return PInvoke.DwmSetWindowAttribute(
                new(windowHelper.Handle),
                DWMWINDOWATTRIBUTE.DWMWA_USE_IMMERSIVE_DARK_MODE,
                &darkMode,
                (uint)Marshal.SizeOf<int>()).Succeeded;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="window"></param>
        /// <param name="cornerType">DoNotRound, Round, RoundSmall, Default</param>
        /// <returns></returns>
        public static unsafe bool DWMSetCornerPreferenceForWindow(Window window, string cornerType)
        {
            var windowHelper = new WindowInteropHelper(window);
            windowHelper.EnsureHandle();

            var preference = cornerType switch
            {
                "DoNotRound" => DWM_WINDOW_CORNER_PREFERENCE.DWMWCP_DONOTROUND,
                "Round" => DWM_WINDOW_CORNER_PREFERENCE.DWMWCP_ROUND,
                "RoundSmall" => DWM_WINDOW_CORNER_PREFERENCE.DWMWCP_ROUNDSMALL,
                "Default" => DWM_WINDOW_CORNER_PREFERENCE.DWMWCP_DEFAULT,
                _ => throw new InvalidOperationException("Invalid corner type")
            };

            return PInvoke.DwmSetWindowAttribute(
                new(windowHelper.Handle),
                DWMWINDOWATTRIBUTE.DWMWA_WINDOW_CORNER_PREFERENCE,
                &preference,
                (uint)Marshal.SizeOf<int>()).Succeeded;
        }

        #endregion

        #region Backdrop

        public static bool IsBackdropSupported()
        {
            // Windows 11 (22000) 이상에서만 Mica 및 Acrylic 효과 지원
            return RuntimeInformation.IsOSPlatform(OSPlatform.Windows) &&
                   Environment.OSVersion.Version.Build >= 22000;
        }

        public static unsafe bool SetMicaForWindow(Window window, bool enableMica)
        {
            var windowHelper = new WindowInteropHelper(window);
            windowHelper.EnsureHandle();

            DWM_SYSTEMBACKDROP_TYPE backdropType = enableMica ? DWM_SYSTEMBACKDROP_TYPE.DWMSBT_MAINWINDOW : DWM_SYSTEMBACKDROP_TYPE.DWMSBT_NONE;
            return PInvoke.DwmSetWindowAttribute(
                new(windowHelper.Handle), 
                DWMWINDOWATTRIBUTE.DWMWA_SYSTEMBACKDROP_TYPE,
                &backdropType,
                (uint)Marshal.SizeOf<int>()).Succeeded;
        }

        #endregion

        #region Blur Handling

        /*
        Found on https://github.com/riverar/sample-win10-aeroglass
        */

        private enum AccentState
        {
            ACCENT_DISABLED = 0,
            ACCENT_ENABLE_GRADIENT = 1,
            ACCENT_ENABLE_TRANSPARENTGRADIENT = 2,
            ACCENT_ENABLE_BLURBEHIND = 3,
            ACCENT_INVALID_STATE = 4
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct AccentPolicy
        {
            public AccentState AccentState;
            public int AccentFlags;
            public int GradientColor;
            public int AnimationId;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct WindowCompositionAttributeData
        {
            public WindowCompositionAttribute Attribute;
            public IntPtr Data;
            public int SizeOfData;
        }

        private enum WindowCompositionAttribute
        {
            WCA_ACCENT_POLICY = 19
        }

        [DllImport("user32.dll")]
        private static extern int SetWindowCompositionAttribute(IntPtr hwnd, ref WindowCompositionAttributeData data);

        /// <summary>
        /// Checks if the blur theme is enabled
        /// </summary>
        public static bool IsBlurTheme()
        {
            if (Environment.OSVersion.Version >= new Version(6, 2))
            {
                var resource = Application.Current.TryFindResource("ThemeBlurEnabled");

                if (resource is bool b)
                    return b;

                return false;
            }

            return false;
        }

        /// <summary>
        /// Sets the blur for a window via SetWindowCompositionAttribute
        /// </summary>
        public static void SetBlurForWindow(Window w, bool blur)
        {
            SetWindowAccent(w, blur ? AccentState.ACCENT_ENABLE_BLURBEHIND : AccentState.ACCENT_DISABLED);
        }

        private static void SetWindowAccent(Window w, AccentState state)
        {
            var windowHelper = new WindowInteropHelper(w);

            windowHelper.EnsureHandle();

            var accent = new AccentPolicy { AccentState = state };
            var accentStructSize = Marshal.SizeOf(accent);

            var accentPtr = Marshal.AllocHGlobal(accentStructSize);
            Marshal.StructureToPtr(accent, accentPtr, false);

            var data = new WindowCompositionAttributeData
            {
                Attribute = WindowCompositionAttribute.WCA_ACCENT_POLICY,
                SizeOfData = accentStructSize,
                Data = accentPtr
            };

            SetWindowCompositionAttribute(windowHelper.Handle, ref data);

            Marshal.FreeHGlobal(accentPtr);
        }
        #endregion
    }
}