using System;

using System.Windows.Forms;

using System.Runtime.InteropServices;

using System.Diagnostics;

using System.Text;

using Microsoft.Win32.SafeHandles;

using Win32;

namespace Hid

{

    /// <summary>

    /// Represent a HID device.

    /// </summary>

    public class HidDevice: IDisposable

    {

        public string Name { get; private set; }

        public string Manufacturer { get; private set; }

        public string Product { get; private set; }

        public ushort VendorId { get; private set; }

        public ushort ProductId { get; private set; }

        public ushort Version { get; private set; }

        public IntPtr PreParsedData {get; private set;}

        public RID_DEVICE_INFO Info { get {return iInfo;} }

        private RID_DEVICE_INFO iInfo;

        /// <summary>

        /// Class constructor will fetch this object properties from HID sub system.

        /// </summary>

        /// <param name="hRawInputDevice">Device Handle as provided by RAWINPUTHEADER.hDevice, typically accessed as rawinput.header.hDevice</param>

        public HidDevice(IntPtr hRawInputDevice)

        {

            //Try construct and rollback if needed

            try

            {

                Construct(hRawInputDevice);

            }

            catch (System.Exception ex)

            {

                //Just rollback and propagate

                Dispose();

                throw ex;

            }

        }

        /// <summary>

        /// Make sure dispose is called even if the user forgot about it.

        /// </summary>

        ~HidDevice()

        {

            Dispose();

        }

        /// <summary>

        /// Private constructor.

        /// </summary>

        /// <param name="hRawInputDevice"></param>

        private void Construct(IntPtr hRawInputDevice)

        {

            PreParsedData = IntPtr.Zero;

            //Fetch various information defining the given HID device

            Name = Win32.Utils.RawInput.GetDeviceName(hRawInputDevice);

            //Get our HID descriptor pre-parsed data

            PreParsedData = Win32.Utils.RawInput.GetPreParsedData(hRawInputDevice);

            if (PreParsedData == IntPtr.Zero)

            {

                throw new Exception("HidDevice: GetPreParsedData failed: " + Marshal.GetLastWin32Error().ToString());

            }

            //Fetch device info

            iInfo = new RID_DEVICE_INFO();

            if (!Win32.Utils.RawInput.GetDeviceInfo(hRawInputDevice, ref iInfo))

            {

                throw new Exception("HidDevice: GetDeviceInfo failed: " + Marshal.GetLastWin32Error().ToString());

            }

            //Open our device from the device name/path

            SafeFileHandle handle = Win32.Function.CreateFile(Name,

                Win32.FileAccess.NONE,

                Win32.FileShare.FILE_SHARE_READ | Win32.FileShare.FILE_SHARE_WRITE,

                IntPtr.Zero,

                Win32.CreationDisposition.OPEN_EXISTING,

                Win32.FileFlagsAttributes.FILE_FLAG_OVERLAPPED,

                IntPtr.Zero

                );

            //Check if CreateFile worked

            if (handle.IsInvalid)

            {

                throw new Exception("HidDevice: CreateFile failed: " + Marshal.GetLastWin32Error().ToString());

            }

            //Get manufacturer string

            StringBuilder manufacturerString = new StringBuilder(256);

            if (Win32.Function.HidD_GetManufacturerString(handle, manufacturerString, manufacturerString.Capacity))

            {

                Manufacturer = manufacturerString.ToString();

            }

            //Get product string

            StringBuilder productString = new StringBuilder(256);

            if (Win32.Function.HidD_GetProductString(handle, productString, productString.Capacity))

            {

                Product = productString.ToString();

            }

            //Get attributes

            Win32.HIDD_ATTRIBUTES attributes = new Win32.HIDD_ATTRIBUTES();

            if (Win32.Function.HidD_GetAttributes(handle, ref attributes))

            {

                VendorId = attributes.VendorID;

                ProductId = attributes.ProductID;

                Version = attributes.VersionNumber;

            }

            handle.Close();

        }

        /// <summary>

        /// Dispose is just for unmanaged clean-up.

        /// Make sure calling disposed multiple times does not crash.

        /// See: http://stackoverflow.com/questions/538060/proper-use-of-the-idisposable-interface/538238#538238

        /// </summary>

        public void Dispose()

        {

            Marshal.FreeHGlobal(PreParsedData);

            PreParsedData = IntPtr.Zero;

        }

        /// <summary>

        /// Print information about this device to our debug output.

        /// </summary>

        public void DebugWrite()

        {

            Debug.WriteLine("================ HID =========================================================================================");

            Debug.WriteLine("==== Name: " + Name);

            Debug.WriteLine("==== Manufacturer: " + Manufacturer);

            Debug.WriteLine("==== Product: " + Product);

            Debug.WriteLine("==== VendorID: 0x" + VendorId.ToString("X4"));

            Debug.WriteLine("==== ProductID: 0x" + ProductId.ToString("X4"));

            Debug.WriteLine("==== Version: " + Version.ToString());

            Debug.WriteLine("==============================================================================================================");

        }

    }

}