using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Translate
{
    public class HotKeyClass
    {
        private IntPtr m_WindowHandle = IntPtr.Zero;
        private MODKEY m_ModKey = MODKEY.MOD_CONTROL;
        private Keys m_Keys = Keys.A;
        private int m_WParam = 10000;
        private bool Star = false;
        private HotKeyWndProc m_HotKeyWnd = new HotKeyWndProc();

        public IntPtr WindowHandle
        {
            get { return m_WindowHandle; }
            set { if (Star)return; m_WindowHandle = value; }
        }
        public MODKEY ModKey
        {
            get { return m_ModKey; }
            set { if (Star)return; m_ModKey = value; }
        }
        public Keys Keys
        {
            get { return m_Keys; }
            set { if (Star)return; m_Keys = value; }
        }
        public int WParam
        {
            get { return m_WParam; }
            set { if (Star)return; m_WParam = value; }
        }

        public void StarHotKey()
        {
            if (m_WindowHandle != IntPtr.Zero)
            {
                if (!RegisterHotKey(m_WindowHandle, m_WParam, m_ModKey, m_Keys))
                {
                    throw new Exception("Register Failed!");
                }
                try
                {
                    m_HotKeyWnd.m_HotKeyPass = new HotKeyPass(KeyPass);
                    m_HotKeyWnd.m_WParam = m_WParam;
                    m_HotKeyWnd.AssignHandle(m_WindowHandle);
                    Star = true;
                }
                catch
                {
                    StopHotKey();
                }
            }
        }
        private void KeyPass()
        {
            if (HotKey != null) HotKey();
        }
        public void StopHotKey()
        {
            if (Star)
            {
                if (!UnregisterHotKey(m_WindowHandle, m_WParam))
                {
                    throw new Exception("Uninstall Failed!");
                }
                Star = false;
                m_HotKeyWnd.ReleaseHandle();
            }
        }


        public delegate void HotKeyPass();
        public event HotKeyPass HotKey;


        private class HotKeyWndProc : NativeWindow
        {
            public int m_WParam = 10000;
            public HotKeyPass m_HotKeyPass;
            protected override void WndProc(ref Message m)
            {
                if (m.Msg == 0x0312 && m.WParam.ToInt32() == m_WParam)
                {
                    if (m_HotKeyPass != null) m_HotKeyPass.Invoke();
                }

                base.WndProc(ref m);
            }
        }

        public enum MODKEY
        {
            MOD_ALT = 0x0001,
            MOD_CONTROL = 0x0002,
            MOD_SHIFT = 0x0004,
            MOD_WIN = 0x0008,
        }

        [DllImport("user32.dll")]
        public static extern bool RegisterHotKey(IntPtr wnd, int id, MODKEY mode, Keys vk);

        [DllImport("user32.dll")]
        public static extern bool UnregisterHotKey(IntPtr wnd, int id);

    }
}