Program.cs

namespace FolderStatus;

using System;
using System.IO;
using System.Runtime.InteropServices;

internal class Program
{
    private const uint FCS_FORCEWRITE = 0x00000002; // Forces an immediate shell refresh
    private const uint FCSM_ICONFILE  = 0x00000010; // Tells Windows we are changing the icon

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public struct SHFOLDERCUSTOMSETTINGS
    {
        public uint dwSize;
        public uint dwMask;
        public IntPtr pvid;
        public string pszWebViewTemplate;
        public uint cchWebViewTemplate;
        public string pszWebViewTemplateVersion;
        public string pszInfoTip;
        public uint cchInfoTip;
        public IntPtr pclsid;
        public uint dwFlags;
        public string? pszIconFile; // Maps to fcs.pszIconFile
        public uint cchIconFile;    // Maps to fcs.cchIconFile
        public int iIconIndex;      // Maps to fcs.iIconIndex
        public string pszLogo;
        public uint cchLogo;
    }

    [DllImport("shell32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    public static extern int SHGetSetFolderCustomSettings(ref SHFOLDERCUSTOMSETTINGS pfs,string pszPath, uint dwReadWrite);


    static void Main(string[] args)
    {

        if (args.Length < 2)
        {
            Console.WriteLine("Missing parameters");
            Log("Missing parameters");
            return;
        }

        string action = args[0].ToLowerInvariant().Trim();
        string folderPath = args[1];

        if (!Directory.Exists(folderPath))
        {
            Console.WriteLine("Folder does not exist");
            Log("Folder does not exist");
            return;
        }

        try
        {
            ProcessFolderStatus(action, folderPath);
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            Log(ex.Message);
        }
    }

    static void ProcessFolderStatus(string action, string folderPath)
    {
        switch (action)
        {
            case "done":
                WriteAndRefreshIcon(folderPath, @"C:\Program Files\FolderStatus\status\Completed.ico");
                break;
            case "progress":
                WriteAndRefreshIcon(folderPath, @"C:\Program Files\FolderStatus\status\InProgress.ico");
                break;
            case "restore":
                WriteAndRefreshIcon(folderPath, null);
                break;
            default:
                Console.WriteLine("Invalid action");
                Log("Invalid action");
                return;
        }

        Log("Successfully applied folder status");
    }

    static void WriteAndRefreshIcon(string folderPath, string? iconPath, int iconIndex=0)
    {
        SHFOLDERCUSTOMSETTINGS fcs = new SHFOLDERCUSTOMSETTINGS();
        
        // fcs.dwSize = sizeof(SHFOLDERCUSTOMSETTINGS);
        fcs.dwSize = (uint)Marshal.SizeOf(typeof(SHFOLDERCUSTOMSETTINGS));
        
        // fcs.dwMask = FCSM_ICONFILE;
        fcs.dwMask = FCSM_ICONFILE;
        
        // fcs.pszIconFile = iconPath;
        fcs.pszIconFile = iconPath;
        
        // fcs.cchIconFile = 0;
        fcs.cchIconFile = 0;
        
        // fcs.iIconIndex = iconIndex;
        fcs.iIconIndex = iconIndex;

        // SHGetSetFolderCustomSettings(&fcs, folderPath, FCS_FORCEWRITE);
        // In C#, passing by 'ref' automatically passes the memory address (&fcs)
        int hResult = SHGetSetFolderCustomSettings(ref fcs, folderPath, FCS_FORCEWRITE);

        if (hResult != 0)
        {
            Console.WriteLine("Failed to refresh folder status");
            Log("Failed to refresh folder status");
        }
    }


    static void WriteCustomIcon(string iniPath, string iconPath)
    {
        if (File.Exists(iniPath))
        {
            File.SetAttributes(iniPath, FileAttributes.Normal);
        }
        string[] iniLines = new string[]
        {
            "[.ShellClassInfo]",
            $"IconResource={iconPath},0"
        };
        File.WriteAllLines(iniPath, iniLines);
    }

    static void ApplyAttributes(string folderPath, string iniPath)
    {
        // desktop.ini file must be marked as hidden, archive and system file for it to work
        File.SetAttributes(iniPath, FileAttributes.Archive | FileAttributes.Hidden | FileAttributes.System);

        // the folder with the desktop file must also be read only for some reason?
        File.SetAttributes(folderPath, FileAttributes.ReadOnly);
    }

    static void ResetFolderDefaults(string folderPath, string iniPath)
    {
        if (File.Exists(iniPath))
        {
            File.SetAttributes(iniPath, FileAttributes.Normal);
            File.Delete(iniPath);
        }
        DirectoryInfo folderInfo = new DirectoryInfo(folderPath);
        folderInfo.Attributes &= ~FileAttributes.ReadOnly;
    }
    static void Log(string message)
    {
        string logPath = Path.Combine(Path.GetTempPath(), "FolderStatus.log");
        File.AppendAllText(logPath,
            $"{DateTime.Now:HH:mm:ss} {message}{Environment.NewLine}");
    }
}