using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace TibisMathematicsSuite.KeyboardIO
{
    public static class Hotkey
    {
        private static HotkeyWindow window = new HotkeyWindow();
        private static int currentId = 0;

        public static event EventHandler<MyKeyEventArgs> HotkeyPressed
        {
            add { window.HotkeyPressed += value; }
            remove { window.HotkeyPressed -= value; }
        }

        #region Winapi routines
        // Registers a hot key with Windows.
        [DllImport("user32.dll")]
        private static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk);

        // Unregisters the hot key with Windows.
        [DllImport("user32.dll")]
        private static extern bool UnregisterHotKey(IntPtr hWnd, int id);
        #endregion

        public static void Register(MyKey key)
        {
            currentId++;

            if (!RegisterHotKey(window.Handle, currentId, (uint)key.Mods, (uint)key.Key))
                throw new InvalidOperationException("Could not register the hotkey!");
        }

        public static void UnregisterAll()
        {
            for (; currentId > 0; currentId--)
                UnregisterHotKey(window.Handle, currentId);
        }
    }
}