using System;
using System.Runtime.InteropServices;

namespace FontPreview;

internal static class NativeFolderDialog
{
	private const uint FOS_PICKFOLDERS = 32u;

	private const int SIGDN_FILESYSPATH = -2147123200;

	[DllImport("shell32.dll", CharSet = CharSet.Unicode)]
	private static extern int SHCreateItemFromParsingName([MarshalAs(UnmanagedType.LPWStr)] string pszPath, IntPtr pbc, ref Guid riid, out IntPtr ppv);

	private static void AddNavPlace(IFileOpenDialog dlg, string clsidPath)
	{
		try
		{
			IntPtr ppv = IntPtr.Zero;
			Guid riid = new Guid("43826d1e-e718-42ee-bc55-a1e261c37bfe");
			if (SHCreateItemFromParsingName(clsidPath, IntPtr.Zero, ref riid, out ppv) == 0 && ppv != IntPtr.Zero)
			{
				IShellItem psi = (IShellItem)Marshal.GetObjectForIUnknown(ppv);
				try
				{
					dlg.AddPlace(psi, 1);
					return;
				}
				catch
				{
					return;
				}
			}
		}
		catch
		{
		}
	}

	internal static string PickFolder(IntPtr owner, string title, string initialPath)
	{
		IFileOpenDialog fileOpenDialog = (IFileOpenDialog)new FileOpenDialogRCW();
		try
		{
			fileOpenDialog.SetTitle(title);
			fileOpenDialog.SetOptions(32u);
			AddNavPlace(fileOpenDialog, "::{20D04FE0-3AEA-1069-A2D8-08002B30309D}");
			AddNavPlace(fileOpenDialog, "::{208D2C60-3AEA-1069-A2D8-08002B30309D}");
			if (!string.IsNullOrEmpty(initialPath))
			{
				try
				{
					IntPtr ppv = IntPtr.Zero;
					Guid riid = new Guid("43826d1e-e718-42ee-bc55-a1e261c37bfe");
					if (SHCreateItemFromParsingName(initialPath, IntPtr.Zero, ref riid, out ppv) == 0 && ppv != IntPtr.Zero)
					{
						IShellItem folder = (IShellItem)Marshal.GetObjectForIUnknown(ppv);
						fileOpenDialog.SetFolder(folder);
					}
				}
				catch
				{
				}
			}
			if (fileOpenDialog.Show(owner) != 0)
			{
				return null;
			}
			fileOpenDialog.GetResult(out var ppsi);
			if (ppsi == null)
			{
				return null;
			}
			ppsi.GetDisplayName(-2147123200, out var ppszName);
			if (ppszName == IntPtr.Zero)
			{
				return null;
			}
			string result = Marshal.PtrToStringUni(ppszName);
			Marshal.FreeCoTaskMem(ppszName);
			return result;
		}
		finally
		{
			try
			{
				Marshal.FinalReleaseComObject(fileOpenDialog);
			}
			catch
			{
			}
		}
	}
}