using System;
using System.Collections.Generic;
using SlimDX.XInput;

namespace BizHawk.Client.EmuHawk
{
	public class GamePad360
	{
		// ********************************** Static interface **********************************

		public static List<GamePad360> Devices = new List<GamePad360>();

		static bool IsAvailable;

		public static void Initialize()
		{
			IsAvailable = false;
			try
			{
				//some users wont even have xinput installed. in order to avoid spurious exceptions and possible instability, check for the library first
				IntPtr lib = Win32.LoadLibrary("xinput1_3.dll");
				if (lib != IntPtr.Zero)
				{
					Win32.FreeLibrary(lib);
					
					//don't remove this code. it's important to catch errors on systems with broken xinput installs.
					//(probably, checking for the library was adequate, but lets not get rid of this anyway)
					var test = new SlimDX.XInput.Controller(UserIndex.One).IsConnected;
					IsAvailable = true;
				}
			}
			catch { }

			if (!IsAvailable) return;

			var c1 = new Controller(UserIndex.One);
			var c2 = new Controller(UserIndex.Two);
			var c3 = new Controller(UserIndex.Three);
			var c4 = new Controller(UserIndex.Four);

			if (c1.IsConnected) Devices.Add(new GamePad360(c1));
			if (c2.IsConnected) Devices.Add(new GamePad360(c2));
			if (c3.IsConnected) Devices.Add(new GamePad360(c3));
			if (c4.IsConnected) Devices.Add(new GamePad360(c4));
		}

		public static void UpdateAll()
		{
			if(IsAvailable)
				foreach (var device in Devices)
					device.Update();
		}

		// ********************************** Instance Members **********************************

		readonly Controller controller;
		State state;

		GamePad360(Controller c)
		{
			controller = c;
			InitializeButtons();
			Update();
		}

		public void Update()
		{
			if (controller.IsConnected == false)
				return;

			state = controller.GetState();
		}

		public IEnumerable<Tuple<string, float>> GetFloats()
		{
			var g = state.Gamepad;
			const float f = 3.2768f;
			yield return new Tuple<string, float>("LeftThumbX", g.LeftThumbX / f);
			yield return new Tuple<string, float>("LeftThumbY", g.LeftThumbY / f);
			yield return new Tuple<string, float>("RightThumbX", g.RightThumbX / f);
			yield return new Tuple<string, float>("RightThumbY", g.RightThumbY / f);
			yield break;
		}

		public int NumButtons { get; private set; }

		private readonly List<string> names = new List<string>();
		private readonly List<Func<bool>> actions = new List<Func<bool>>();

		void InitializeButtons()
		{
			const int dzp = 9000;
			const int dzn = -9000;
			const int dzt = 40;

			AddItem("A", () => (state.Gamepad.Buttons & GamepadButtonFlags.A) != 0);
			AddItem("B", () => (state.Gamepad.Buttons & GamepadButtonFlags.B) != 0);
			AddItem("X", () => (state.Gamepad.Buttons & GamepadButtonFlags.X) != 0);
			AddItem("Y", () => (state.Gamepad.Buttons & GamepadButtonFlags.Y) != 0);

			AddItem("Start", () => (state.Gamepad.Buttons & GamepadButtonFlags.Start) != 0);
			AddItem("Back", () => (state.Gamepad.Buttons & GamepadButtonFlags.Back) != 0);
			AddItem("LeftThumb", () => (state.Gamepad.Buttons & GamepadButtonFlags.LeftThumb) != 0);
			AddItem("RightThumb", () => (state.Gamepad.Buttons & GamepadButtonFlags.RightThumb) != 0);
			AddItem("LeftShoulder", () => (state.Gamepad.Buttons & GamepadButtonFlags.LeftShoulder) != 0);
			AddItem("RightShoulder", () => (state.Gamepad.Buttons & GamepadButtonFlags.RightShoulder) != 0);

			AddItem("DpadUp", () => (state.Gamepad.Buttons & GamepadButtonFlags.DPadUp) != 0);
			AddItem("DpadDown", () => (state.Gamepad.Buttons & GamepadButtonFlags.DPadDown) != 0);
			AddItem("DpadLeft", () => (state.Gamepad.Buttons & GamepadButtonFlags.DPadLeft) != 0);
			AddItem("DpadRight", () => (state.Gamepad.Buttons & GamepadButtonFlags.DPadRight) != 0);

			AddItem("LStickUp", () => state.Gamepad.LeftThumbY >= dzp);
			AddItem("LStickDown", () => state.Gamepad.LeftThumbY <= dzn);
			AddItem("LStickLeft", () => state.Gamepad.LeftThumbX <= dzn);
			AddItem("LStickRight", () => state.Gamepad.LeftThumbX >= dzp);

			AddItem("RStickUp", () => state.Gamepad.RightThumbY >= dzp);
			AddItem("RStickDown", () => state.Gamepad.RightThumbY <= dzn);
			AddItem("RStickLeft", () => state.Gamepad.RightThumbX <= dzn);
			AddItem("RStickRight", () => state.Gamepad.RightThumbX >= dzp);

			AddItem("LeftTrigger", () => state.Gamepad.LeftTrigger > dzt);
			AddItem("RightTrigger", () => state.Gamepad.RightTrigger > dzt);
		}

		void AddItem(string name, Func<bool> pressed)
		{
			names.Add(name);
			actions.Add(pressed);
			NumButtons++;
		}

		public string ButtonName(int index)
		{
			return names[index];
		}

		public bool Pressed(int index)
		{
			return actions[index]();
		}
	}
}