using System;

 using System.Runtime.InteropServices;

 using System.Diagnostics;

 using System.Windows.Forms;

 namespace Win32

 {

     /// <summary>

     /// Provide some utility functions for raw input handling.

     /// </summary>

     static class RawInput

     {

         /// <summary>

         /// 

         /// </summary>

         /// <param name="aRawInputHandle"></param>

         /// <param name="aRawInput"></param>

         /// <param name="rawInputBuffer">Caller must free up memory on the pointer using Marshal.FreeHGlobal</param>

         /// <returns></returns>

         public static bool GetRawInputData(IntPtr aRawInputHandle, ref RAWINPUT aRawInput, ref IntPtr rawInputBuffer)

         {

             bool success = true;

             rawInputBuffer = IntPtr.Zero;

             try

             {

                 uint dwSize = 0;

                 uint sizeOfHeader = (uint)Marshal.SizeOf(typeof(RAWINPUTHEADER));

                 //Get the size of our raw input data.

                 Win32.Function.GetRawInputData(aRawInputHandle, Const.RID_INPUT, IntPtr.Zero, ref dwSize, sizeOfHeader);

                 //Allocate a large enough buffer

                  rawInputBuffer = Marshal.AllocHGlobal((int)dwSize);

                 //Now read our RAWINPUT data

                 if (Win32.Function.GetRawInputData(aRawInputHandle, Const.RID_INPUT, rawInputBuffer, ref dwSize, (uint)Marshal.SizeOf(typeof(RAWINPUTHEADER))) != dwSize)

                 {

                     return false;

                 }

                 //Cast our buffer

                 aRawInput = (RAWINPUT)Marshal.PtrToStructure(rawInputBuffer, typeof(RAWINPUT));

             }

             catch

             {

                 Debug.WriteLine("GetRawInputData failed!");

                 success = false;

             }

             return success;

         }

         /// <summary>

         /// 

         /// </summary>

         /// <param name="hDevice"></param>

         /// <param name="deviceInfo"></param>

         /// <returns></returns>

         public static bool GetDeviceInfo(IntPtr hDevice, ref RID_DEVICE_INFO deviceInfo)

         {

             bool success = true;

             IntPtr deviceInfoBuffer = IntPtr.Zero;

             try

             {

                 //Get Device Info

                 uint deviceInfoSize = (uint)Marshal.SizeOf(typeof(RID_DEVICE_INFO));

                 deviceInfoBuffer = Marshal.AllocHGlobal((int)deviceInfoSize);

                 int res = Win32.Function.GetRawInputDeviceInfo(hDevice, Win32.RawInputDeviceInfoType.RIDI_DEVICEINFO, deviceInfoBuffer, ref deviceInfoSize);

                 if (res <= 0)

                 {

                     Debug.WriteLine("WM_INPUT could not read device info: " + Marshal.GetLastWin32Error().ToString());

                     return false;

                 }

                 //Cast our buffer

                 deviceInfo = (RID_DEVICE_INFO)Marshal.PtrToStructure(deviceInfoBuffer, typeof(RID_DEVICE_INFO));

             }

             catch

             {

                 Debug.WriteLine("GetRawInputData failed!");

                 success = false;

             }

             finally

             {

                 //Always executes, prevents memory leak

                 Marshal.FreeHGlobal(deviceInfoBuffer);

             }

             return success;

         }

         /// <summary>

         /// Fetch pre-parsed data corresponding to HID descriptor for the given HID device.

         /// </summary>

         /// <param name="device"></param>

         /// <returns></returns>

         public static IntPtr GetPreParsedData(IntPtr hDevice)

         {

             uint ppDataSize = 0;

             int result = Win32.Function.GetRawInputDeviceInfo(hDevice, RawInputDeviceInfoType.RIDI_PREPARSEDDATA, IntPtr.Zero, ref ppDataSize);

             if (result != 0)

             {

                 Debug.WriteLine("Failed to get raw input pre-parsed data size" + result + Marshal.GetLastWin32Error());

                 return IntPtr.Zero;

             }

             IntPtr ppData = Marshal.AllocHGlobal((int)ppDataSize);

             result = Win32.Function.GetRawInputDeviceInfo(hDevice, RawInputDeviceInfoType.RIDI_PREPARSEDDATA, ppData, ref ppDataSize);

             if (result <= 0)

             {

                 Debug.WriteLine("Failed to get raw input pre-parsed data" + result + Marshal.GetLastWin32Error());

                 return IntPtr.Zero;

             }

             return ppData;

         }

         /// <summary>

         /// 

         /// </summary>

         /// <param name="device"></param>

         /// <returns></returns>

         public static string GetDeviceName(IntPtr device)

         {

             uint deviceNameSize = 256;

             int result = Win32.Function.GetRawInputDeviceInfo(device, RawInputDeviceInfoType.RIDI_DEVICENAME, IntPtr.Zero, ref deviceNameSize);

             if (result != 0)

             {

                 return string.Empty;

             }

             IntPtr deviceName = Marshal.AllocHGlobal((int)deviceNameSize * 2);  // size is the character count not byte count

             try

             {

                 result = Win32.Function.GetRawInputDeviceInfo(device, RawInputDeviceInfoType.RIDI_DEVICENAME, deviceName, ref deviceNameSize);

                 if (result > 0)

                 {

                     return Marshal.PtrToStringAnsi(deviceName, result - 1); // -1 for NULL termination

                 }

                 return string.Empty;

             }

             finally

             {

                 Marshal.FreeHGlobal(deviceName);

             }

         }

         /// <summary>

         /// 

         /// </summary>

         /// <param name="aTreeView"></param>

         public static void PopulateDeviceList(TreeView aTreeView)

         {

             //Get our list of devices

             RAWINPUTDEVICELIST[] ridList = null;

             uint deviceCount = 0;

             int res = Win32.Function.GetRawInputDeviceList(ridList, ref deviceCount,(uint)Marshal.SizeOf(typeof(RAWINPUTDEVICELIST)));

             if (res == -1)

             {

                 //Just give up then

                 return;

             }

             ridList = new RAWINPUTDEVICELIST[deviceCount];

             res = Win32.Function.GetRawInputDeviceList(ridList, ref deviceCount, (uint)Marshal.SizeOf(typeof(RAWINPUTDEVICELIST)));

             if (res != deviceCount)

             {

                 //Just give up then

                 return;

             }

             //For each our device add a node to our treeview

             foreach (RAWINPUTDEVICELIST device in ridList)

             {

                 Hid.HidDevice hidDevice=new Hid.HidDevice(device.hDevice);

                 //Work out proper suffix for our device root node.

                 //That allows users to see in a glance what kind of device this is.

                 string suffix = "";

                 if (hidDevice.Info.dwType == RawInputDeviceType.RIM_TYPEHID)

                 {

                     //Process usage page

                     if (Enum.IsDefined(typeof(Hid.UsagePage), hidDevice.Info.hid.usUsagePage))

                     {

                         //We know this usage page, add its name

                         Hid.UsagePage usagePage = (Hid.UsagePage)hidDevice.Info.hid.usUsagePage;

                         suffix += " ( " + usagePage.ToString() + ", ";

                     }

                     else

                     {

                         //We don't know this usage page, add its value

                         suffix += " ( 0x" + hidDevice.Info.hid.usUsagePage.ToString("X4") + ", ";

                     }

                     //Process usage

                     //We don't know this usage page, add its value

                     suffix += "0x" + hidDevice.Info.hid.usUsage.ToString("X4") + " )";

                 }

                 else if (hidDevice.Info.dwType == RawInputDeviceType.RIM_TYPEKEYBOARD)

                 {

                     suffix = " - Keyboard";

                 }

                 else if (hidDevice.Info.dwType == RawInputDeviceType.RIM_TYPEMOUSE)

                 {

                     suffix = " - Mouse";

                 }

                 TreeNode node = null;

                 if (hidDevice.Product != null && hidDevice.Product.Length > 1)

                 {

                     //Add the devices with a proper name at the top

                     node = aTreeView.Nodes.Insert(0, hidDevice.Name, hidDevice.Product + suffix);

                 }

                 else

                 {

                     //Add other once at the bottom

                     node = aTreeView.Nodes.Add(hidDevice.Name, "0x" + hidDevice.ProductId.ToString("X4") + suffix);

                 }

                 node.Nodes.Add("Manufacturer: " + hidDevice.Manufacturer);

                 node.Nodes.Add("Product ID: 0x" + hidDevice.ProductId.ToString("X4"));

                 node.Nodes.Add("Vendor ID: 0x" + hidDevice.VendorId.ToString("X4"));

                 node.Nodes.Add("Version: " + hidDevice.Version);

                 node.Nodes.Add(hidDevice.Info.dwType.ToString());

                 if (hidDevice.Info.dwType == RawInputDeviceType.RIM_TYPEHID)

                 {

                     node.Nodes.Add("UsagePage / UsageCollection: 0x" + hidDevice.Info.hid.usUsagePage.ToString("X4") + " / 0x" + hidDevice.Info.hid.usUsage.ToString("X4"));

                 }

                 node.Nodes.Add(hidDevice.Name);

             }

         }

     }

 }