using System.Collections.Generic;
using SlimDX;
using SlimDX.DirectInput;

namespace BizHawk.Client.EmuHawk
{
	public static class KeyInput
	{
		private static DirectInput dinput;
		private static Keyboard keyboard;
		private static KeyboardState state = new KeyboardState();

		public static void Initialize()
		{
			if (dinput == null)
				dinput = new DirectInput();

			if (keyboard == null || keyboard.Disposed)
				keyboard = new Keyboard(dinput);
			keyboard.SetCooperativeLevel(GlobalWin.MainForm.Handle, CooperativeLevel.Background | CooperativeLevel.Nonexclusive);
			keyboard.Properties.BufferSize = 8;
		}

		static List<KeyEvent> EmptyList = new List<KeyEvent>();
		static List<KeyEvent> EventList = new List<KeyEvent>();

		public static IEnumerable<KeyEvent> Update()
		{
			EventList.Clear();

			if (keyboard.Acquire().IsFailure)
				return EmptyList;
			if (keyboard.Poll().IsFailure)
				return EmptyList;

			for (; ; )
			{
				var events = keyboard.GetBufferedData();
				if (Result.Last.IsFailure)
					return EventList;
				if (events.Count == 0)
					break;
				foreach (var e in events)
				{
					foreach (var k in e.PressedKeys)
						EventList.Add(new KeyEvent { Key = k, Pressed = true });
					foreach (var k in e.ReleasedKeys)
						EventList.Add(new KeyEvent { Key = k, Pressed = false });
				}
			}

			return EventList;
		}

		public struct KeyEvent
		{
			public Key Key;
			public bool Pressed;
		}

	}
}