using Godot;
using System;
using System.Runtime.InteropServices;

public partial class RSMousePass : Node
{
    // GetActiveWindow() retrieves the handle of the currently active window on the desktop.
    [DllImport("user32.dll")]
    public static extern IntPtr GetActiveWindow();

    //  SetWindowLong() modifies a specific flag value associated with a window.
    [DllImport("user32.dll")]
    private static extern int SetWindowLong(IntPtr hWnd, int nIndex, uint dwNewLong);

    private const int GwlExStyle = -20;

    // "Properties" of the window to be set, Layered is to have transparent pixels, Transparent is to make the window click-through
    private const uint WsExLayered = 0x00080000;
    private const uint WsExTransparent = 0x00000020;

    // index reference of the window
    private IntPtr _hWnd;

    public override void _Ready()
    {
        // Get the reference of the game window
        _hWnd = GetActiveWindow();

        // setting the flags of becoming a layered and transparent window
        // SetWindowLong(_hWnd, GwlExStyle, WsExLayered | WsExTransparent);
        SetWindowLong(_hWnd, GwlExStyle, WsExLayered);
    }

    // Call this method via your preferred detection algorythm (personally I check the
    // pixel under cursor to have alpha < 0.5f but you do you)
    public void SetClickThrough(bool clickthrough)
    {
        if (clickthrough)
        {
            SetWindowLong(_hWnd, GwlExStyle, WsExLayered | WsExTransparent);
        }
        else
        {
            SetWindowLong(_hWnd, GwlExStyle, WsExLayered);
        }
    }
}