using System;
using System.Drawing;
using System.Runtime.InteropServices;
using Microsoft.Win32;

// The 'windowHandle' parameter will contain the window handle for the:
//   - Active window when run by hotkey
//   - Window Location target when run by a Window Location rule
//   - TitleBar Button owner when run by a TitleBar Button
//   - Jump List owner when run from a Taskbar Jump List
//   - Currently focused window if none of these match
public static class DisplayFusionFunction
{
	//this function lets us tell windows that we changed the cursor
	[DllImport("user32.dll", SetLastError = true)]
	[return: MarshalAs(UnmanagedType.Bool)]
	static extern bool SystemParametersInfo(uint uiAction, uint uiParam, IntPtr pvParam, uint fWinIni);
	const uint SPI_SETCURSORS = 0x0057;
	
	public static void Run(IntPtr windowHandle)
	{
		//this will hold the cursors that the user has installed
		string[] cursors;
		
		//open the registry to get the cursors the user has installed
		using (RegistryKey regkey = Registry.LocalMachine.CreateSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Control Panel\Cursors\Schemes", RegistryKeyPermissionCheck.ReadSubTree))
		{
			//if we couldn't open the registry, tell the user and exit
			if (regkey == null)
			{
				BFS.Dialog.ShowMessageError("Unable to get cursors");
				return;
			}

			//convert the value into a list
			cursors = regkey.GetValueNames();
		}
		
		//sort the cursors to the user can read them better
		Array.Sort(cursors);
		
		//let the user pick which cursor they want
		string cursor = BFS.Dialog.GetUserInputList("Select Mouse Cursor", cursors);
		
		//if they pressed cancel, exit
		if(string.IsNullOrEmpty(cursor))
			return;
					
		//this will hold the paths to the cursor files (.cur)
		string[] cursorPaths;
		
		//open the selected registry entry and get the paths
		using(RegistryKey regKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Control Panel\Cursors\Schemes", RegistryKeyPermissionCheck.ReadSubTree))
		{
			//if we couldn't open the registry, tell the user and exit
			if (regKey == null)
			{
				BFS.Dialog.ShowMessageError("Unable to get cursor paths");
				return;
			}
			
			//read the registry path
			object value = regKey.GetValue(cursor, "");
			
			//the paths are seperated by commas, split up the string
			cursorPaths = value.ToString().Split(new char[]{','});
		}
		
		//this is the order than the paths appear in the comma seperated path
		string[] pathKeys = new string[]{"Arrow", "Help", "AppStarting", "Wait", "Crosshair", "IBeam", "NWPen", "No", "SizeNS", "SizeWE", "SizeNWSE", "SizeNESW", "SizeAll", "UpArrow", "Hand", ""};
		
		//if we don't have enough paths, tell the user and exit
		if(cursorPaths.Length < pathKeys.Length)
		{
			BFS.Dialog.ShowMessageError("Not enough paths");
			return;
		}
		
		//open the registry and set the used cursor values to the new ones we found
		using(RegistryKey regKey = Registry.CurrentUser.CreateSubKey(@"Control Panel\Cursors", RegistryKeyPermissionCheck.ReadWriteSubTree))
		{
			//if we couldn't open the registry, tell the user and exit
			if (regKey == null)
			{
				BFS.Dialog.ShowMessageError("Unable set cursors");
				return;
			}
			
			//set each path
			for(int i = 0; i < pathKeys.Length; i++)
				regKey.SetValue(pathKeys[i], cursorPaths[i], RegistryValueKind.String);
		}
		
		//tell windows we changed the cursor so it gets updated
		SystemParametersInfo(SPI_SETCURSORS, 0, IntPtr.Zero, 0);
	}
}