using System;

using System.Windows.Forms;

using System.Runtime.InteropServices;

using System.Diagnostics;

using System.Text;

using Microsoft.Win32.SafeHandles;

using Win32;

using System.Collections.Generic;

using System.Timers;

namespace Hid

{

    /// <summary>

    /// Represent a HID event.

    /// TODO: Rename this into HidRawInput?

    /// </summary>

    public class HidEvent : IDisposable

    {

        public bool IsValid { get; private set; }

        public bool IsForeground { get; private set; }

        public bool IsBackground { get { return !IsForeground; } }

        public bool IsMouse { get; private set; }

        public bool IsKeyboard { get; private set; }

        public bool IsGeneric { get; private set; }

        public bool IsButtonDown { get { return Usages.Count == 1 && Usages[0] != 0; } }

        public bool IsButtonUp { get { return Usages.Count == 0; } }

        public bool IsRepeat { get { return RepeatCount != 0; } }

        public uint RepeatCount { get; private set; }

        public HidDevice Device { get; private set; }

        public ushort UsagePage { get; private set; }

        public ushort UsageCollection { get; private set; }

        public uint UsageId { get { return ((uint)UsagePage << 16 | (uint)UsageCollection); } }

        public List<ushort> Usages { get; private set; }

        //TODO: We need a collection of input report

        public byte[] InputReport { get; private set; }

        //

        public delegate void HidEventRepeatDelegate(HidEvent aHidEvent);

        public event HidEventRepeatDelegate OnHidEventRepeat;

        private System.Timers.Timer Timer { get; set; }

        public DateTime Time { get; private set; }

        public DateTime OriginalTime { get; private set; }

        //Compute repeat delay and speed based on system settings

        //Those computations were taken from the Petzold here: ftp://ftp.charlespetzold.com/ProgWinForms/4%20Custom%20Controls/NumericScan/NumericScan/ClickmaticButton.cs

        private int iRepeatDelay = 250 * (1 + SystemInformation.KeyboardDelay);

        private int iRepeatSpeed = 405 - 12 * SystemInformation.KeyboardSpeed;

        /// <summary>

        /// Tells whether this event has already been disposed of.

        /// </summary>

        public bool IsStray { get { return Timer == null; } }

        /// <summary>

        /// We typically dispose of events as soon as we get the corresponding key up signal.

        /// </summary>

        public void Dispose()

        {

            Timer.Enabled = false;

            Timer.Dispose();

            //Mark this event as a stray

            Timer = null;

        }

        /// <summary>

        /// Initialize an HidEvent from a WM_INPUT message

        /// </summary>

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

        public HidEvent(Message aMessage, HidEventRepeatDelegate aRepeatDelegate)

        {

            RepeatCount = 0;

            IsValid = false;

            IsKeyboard = false;

            IsGeneric = false;

            Time = DateTime.Now;

            OriginalTime = DateTime.Now;

            Timer = new System.Timers.Timer();

            Timer.Elapsed += (sender, e) => OnRepeatTimerElapsed(sender, e, this);

            Usages = new List<ushort>();

            OnHidEventRepeat += aRepeatDelegate;

            if (aMessage.Msg != Const.WM_INPUT)

            {

                //Has to be a WM_INPUT message

                return;

            }

            if (Macro.GET_RAWINPUT_CODE_WPARAM(aMessage.WParam) == Const.RIM_INPUT)

            {

                IsForeground = true;

            }

            else if (Macro.GET_RAWINPUT_CODE_WPARAM(aMessage.WParam) == Const.RIM_INPUTSINK)

            {

                IsForeground = false;

            }

            //Declare some pointers

            IntPtr rawInputBuffer = IntPtr.Zero;

            try

            {

                //Fetch raw input

                RAWINPUT rawInput = new RAWINPUT();

                if (!Win32.RawInput.GetRawInputData(aMessage.LParam, ref rawInput, ref rawInputBuffer))

                {

                    Debug.WriteLine("GetRawInputData failed!");

                    return;

                }

                //Our device can actually be null.

                //This is notably happening for some keyboard events

                if (rawInput.header.hDevice != IntPtr.Zero)

                {

                    //Get various information about this HID device

                    Device = new Hid.HidDevice(rawInput.header.hDevice);

                }

                if (rawInput.header.dwType == Win32.RawInputDeviceType.RIM_TYPEHID)  //Check that our raw input is HID                        

                {

                    IsGeneric = true;

                    Debug.WriteLine("WM_INPUT source device is HID.");

                    //Get Usage Page and Usage

                    //Debug.WriteLine("Usage Page: 0x" + deviceInfo.hid.usUsagePage.ToString("X4") + " Usage ID: 0x" + deviceInfo.hid.usUsage.ToString("X4"));

                    UsagePage = Device.Info.hid.usUsagePage;

                    UsageCollection = Device.Info.hid.usUsage;

                    if (!(rawInput.hid.dwSizeHid > 1     //Make sure our HID msg size more than 1. In fact the first ushort is irrelevant to us for now

                        && rawInput.hid.dwCount > 0))    //Check that we have at least one HID msg

                    {

                        return;

                    }

                    //Allocate a buffer for one HID input

                    InputReport = new byte[rawInput.hid.dwSizeHid];

                    Debug.WriteLine("Raw input contains " + rawInput.hid.dwCount + " HID input report(s)");

                    //For each HID input report in our raw input

                    for (int i = 0; i < rawInput.hid.dwCount; i++)

                    {

                        //Compute the address from which to copy our HID input

                        int hidInputOffset = 0;

                        unsafe

                        {

                            byte* source = (byte*)rawInputBuffer;

                            source += sizeof(RAWINPUTHEADER) + sizeof(RAWHID) + (rawInput.hid.dwSizeHid * i);

                            hidInputOffset = (int)source;

                        }

                        //Copy HID input into our buffer

                        Marshal.Copy(new IntPtr(hidInputOffset), InputReport, 0, (int)rawInput.hid.dwSizeHid);

                        //Print HID input report in our debug output

                        //string hidDump = "HID input report: " + InputReportString();

                        //Debug.WriteLine(hidDump);

                        //Do proper parsing of our HID report

                        //First query our usage count

                        uint usageCount = 0;

                        Win32.USAGE_AND_PAGE[] usages = null;

                        Win32.HidStatus status = Win32.Function.HidP_GetUsagesEx(Win32.HIDP_REPORT_TYPE.HidP_Input, 0, usages, ref usageCount, Device.PreParsedData, InputReport, (uint)InputReport.Length);

                        if (status == Win32.HidStatus.HIDP_STATUS_BUFFER_TOO_SMALL)

                        {

                            //Allocate a large enough buffer 

                            usages = new Win32.USAGE_AND_PAGE[usageCount];

                            //...and fetch our usages

                            status = Win32.Function.HidP_GetUsagesEx(Win32.HIDP_REPORT_TYPE.HidP_Input, 0, usages, ref usageCount, Device.PreParsedData, InputReport, (uint)InputReport.Length);

                            if (status != Win32.HidStatus.HIDP_STATUS_SUCCESS)

                            {

                                Debug.WriteLine("Second pass could not parse HID data: " + status.ToString());

                            }

                        }

                        else if (status != Win32.HidStatus.HIDP_STATUS_SUCCESS)

                        {

                            Debug.WriteLine("First pass could not parse HID data: " + status.ToString());

                        }

                        Debug.WriteLine("Usage count: " + usageCount.ToString());

                        //Copy usages into this event

                        if (usages != null)

                        {

                            foreach (USAGE_AND_PAGE up in usages)

                            {

                                //Debug.WriteLine("UsagePage: 0x" + usages[0].UsagePage.ToString("X4"));

                                //Debug.WriteLine("Usage: 0x" + usages[0].Usage.ToString("X4"));

                                //Add this usage to our list

                                Usages.Add(up.Usage);

                            }

                        }

                    }

                }

                else if (rawInput.header.dwType == RawInputDeviceType.RIM_TYPEMOUSE)

                {

                    IsMouse = true;

                    Debug.WriteLine("WM_INPUT source device is Mouse.");

                    // do mouse handling...

                }

                else if (rawInput.header.dwType == RawInputDeviceType.RIM_TYPEKEYBOARD)

                {

                    IsKeyboard = true;

                    Debug.WriteLine("WM_INPUT source device is Keyboard.");

                    // do keyboard handling...

                    if (Device != null)

                    {

                        Debug.WriteLine("Type: " + Device.Info.keyboard.dwType.ToString());

                        Debug.WriteLine("SubType: " + Device.Info.keyboard.dwSubType.ToString());

                        Debug.WriteLine("Mode: " + Device.Info.keyboard.dwKeyboardMode.ToString());

                        Debug.WriteLine("Number of function keys: " + Device.Info.keyboard.dwNumberOfFunctionKeys.ToString());

                        Debug.WriteLine("Number of indicators: " + Device.Info.keyboard.dwNumberOfIndicators.ToString());

                        Debug.WriteLine("Number of keys total: " + Device.Info.keyboard.dwNumberOfKeysTotal.ToString());

                    }

                }

            }

            finally

            {

                //Always executed when leaving our try block

                Marshal.FreeHGlobal(rawInputBuffer);

            }

            //

            if (IsButtonDown)

            {

                //TODO: Make this optional

                //StartRepeatTimer(iRepeatDelay);

            }

            IsValid = true;

        }

        public void StartRepeatTimer(double aInterval)

        {

            if (Timer == null)

            {

                return;

            }

            Timer.Enabled = false;

            //Initial delay do not use auto reset

            //After our initial delay however we do setup our timer one more time using auto reset

            Timer.AutoReset = (RepeatCount != 0);

            Timer.Interval = aInterval;

            Timer.Enabled = true;

        }

        static private void OnRepeatTimerElapsed(object sender, ElapsedEventArgs e, HidEvent aHidEvent)

        {

            if (aHidEvent.IsStray)

            {

                //Skip events if canceled

                return;

            }

            aHidEvent.RepeatCount++;

            aHidEvent.Time = DateTime.Now;

            if (aHidEvent.RepeatCount == 1)

            {

                //Re-Start our timer only after the initial delay 

                aHidEvent.StartRepeatTimer(aHidEvent.iRepeatSpeed);

            }

            //Broadcast our repeat event

            aHidEvent.OnHidEventRepeat(aHidEvent);

        }

        /// <summary>

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

        /// </summary>

        public void DebugWrite()

        {

            if (!IsValid)

            {

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

                return;

            }

            if (Device!=null)

            {

                Device.DebugWrite();

            }

            if (IsGeneric) Debug.WriteLine("==== Generic");

            if (IsKeyboard) Debug.WriteLine("==== Keyboard");

            if (IsMouse) Debug.WriteLine("==== Mouse");

            Debug.WriteLine("==== Foreground: " + IsForeground.ToString());

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

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

            Debug.WriteLine("==== InputReport: 0x" + InputReportString());

            foreach (ushort usage in Usages)

            {

                Debug.WriteLine("==== Usage: 0x" + usage.ToString("X4"));

            }

        }

        /// <summary>

        /// 

        /// </summary>

        /// <returns></returns>

        public string InputReportString()

        {

            if (InputReport == null)

            {

                return "null";

            }

            string hidDump = "";

            foreach (byte b in InputReport)

            {

                hidDump += b.ToString("X2");

            }

            return hidDump;

        }

        /// <summary>

        /// Create a list view item describing this HidEvent

        /// </summary>

        /// <returns></returns>

        public ListViewItem ToListViewItem()

        {

            string usageText = "";

            foreach (ushort usage in Usages)

            {

                if (usageText != "")

                {

                    //Add a separator

                    usageText += ", ";

                }

                UsagePage usagePage = (UsagePage)UsagePage;

                switch (usagePage)

                {

                    case Hid.UsagePage.Consumer:

                        usageText += ((Hid.Usage.ConsumerControl)usage).ToString();

                        break;

                    case Hid.UsagePage.WindowsMediaCenterRemoteControl:

                        usageText += ((Hid.Usage.WindowsMediaCenterRemoteControl)usage).ToString();

                        break;

                    default:

                        usageText += usage.ToString("X2");

                        break;

                }

            }

            ListViewItem item = new ListViewItem(new[] { usageText, InputReportString(), UsagePage.ToString("X2"), UsageCollection.ToString("X2"), RepeatCount.ToString(), Time.ToString("HH:mm:ss:fff") });

            return item;

        }

    }

}