using System;
using System.Runtime.InteropServices;
using System.Security.Permissions;

namespace BepInEx.ConsoleUtil
{
	internal class Kon
	{
		#region pinvoke

		[DllImport("kernel32.dll", SetLastError = true)]
		private static extern bool GetConsoleScreenBufferInfo(IntPtr hConsoleOutput, out CONSOLE_SCREEN_BUFFER_INFO lpConsoleScreenBufferInfo);

		[DllImport("kernel32.dll", SetLastError = true)]
		private static extern bool SetConsoleTextAttribute(IntPtr hConsoleOutput, short attributes);

		[DllImport("kernel32.dll", SetLastError = true)]
		private static extern IntPtr GetStdHandle(int nStdHandle);

		#endregion

		#region Types

		private struct CONSOLE_SCREEN_BUFFER_INFO
		{
			internal COORD dwSize;
			internal COORD dwCursorPosition;
			internal short wAttributes;
			internal SMALL_RECT srWindow;
			internal COORD dwMaximumWindowSize;
		}

		private struct COORD
		{
			internal short X;
			internal short Y;
		}

		private struct SMALL_RECT
		{
			internal short Left;
			internal short Top;
			internal short Right;
			internal short Bottom;
		}

		private static readonly IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);

		#endregion

		#region Private

		private static short ConsoleColorToColorAttribute(short color, bool isBackground)
		{
			if ((color & -16) != 0)
				throw new ArgumentException("Arg_InvalidConsoleColor");
			if (isBackground)
				color <<= 4;
			return color;
		}

		private static CONSOLE_SCREEN_BUFFER_INFO GetBufferInfo(bool throwOnNoConsole, out bool succeeded)
		{
			succeeded = false;
			if (!(conOut == INVALID_HANDLE_VALUE))
			{
				try
				{
					// FIXME: Windows console shouldn't be used in other OSs in the first place
					CONSOLE_SCREEN_BUFFER_INFO console_SCREEN_BUFFER_INFO;
					if (!GetConsoleScreenBufferInfo(conOut, out console_SCREEN_BUFFER_INFO))
					{
						bool consoleScreenBufferInfo = GetConsoleScreenBufferInfo(GetStdHandle(-12), out console_SCREEN_BUFFER_INFO);
						if (!consoleScreenBufferInfo)
							consoleScreenBufferInfo = GetConsoleScreenBufferInfo(GetStdHandle(-10), out console_SCREEN_BUFFER_INFO);
						
						if (!consoleScreenBufferInfo)
							if (Marshal.GetLastWin32Error() == 6 && !throwOnNoConsole)
								return default(CONSOLE_SCREEN_BUFFER_INFO);
							
							succeeded = true;
						return console_SCREEN_BUFFER_INFO;
					}
				}
				catch (EntryPointNotFoundException)
				{
					// Fails under unsupported OSes
				}
			}

			if (!throwOnNoConsole)
				return default(CONSOLE_SCREEN_BUFFER_INFO);
			throw new Exception("IO.IO_NoConsole");
		}

		private static void SetConsoleColor(bool isBackground, ConsoleColor c)
		{
			new UIPermission(UIPermissionWindow.SafeTopLevelWindows).Demand();
			var color = ConsoleColorToColorAttribute((short)c, isBackground);
			bool flag;
			var bufferInfo = GetBufferInfo(false, out flag);
			if (!flag)
				return;
			var num = bufferInfo.wAttributes;
			num &= (short)(isBackground ? -241 : -16);
			num = (short)((ushort)num | (ushort)color);
			SetConsoleTextAttribute(conOut, num);
		}

		private static ConsoleColor GetConsoleColor(bool isBackground)
		{
			bool flag;
			var bufferInfo = GetBufferInfo(false, out flag);
			if (!flag)
				return isBackground ? ConsoleColor.Black : ConsoleColor.Gray;
			return ColorAttributeToConsoleColor((short)(bufferInfo.wAttributes & 240));
		}

		private static ConsoleColor ColorAttributeToConsoleColor(short c)
		{
			if ((short)(c & 255) != 0)
				c >>= 4;
			return (ConsoleColor)c;
		}

		internal static IntPtr conOut = IntPtr.Zero;

		#endregion

		#region Public

		public static void ResetConsoleColor()
		{
			SetConsoleColor(true, ConsoleColor.Black);
			SetConsoleColor(false, ConsoleColor.Gray);
		}

		public static ConsoleColor ForegroundColor
		{
			get { return GetConsoleColor(false); }
			set { SetConsoleColor(false, value); }
		}

		public static ConsoleColor BackgroundColor
		{
			get { return GetConsoleColor(true); }
			set { SetConsoleColor(true, value); }
		}

		#endregion
	}
}