//
// CurrentOS Class by blez
// http://blez.wordpress.com/2012/09/17/determine-os-with-netmono/
// Detects the current OS (Windows, Linux, MacOS)
//

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.IO;

namespace Blarg.GameFramework
{
	public static class CurrentOS
	{
		public static bool IsWindows { get; private set; }
		public static bool IsUnix { get; private set; }
		public static bool IsMac { get; private set; }
		public static bool IsLinux { get; private set; }
		public static bool IsUnknown { get; private set; }
		public static bool Is32bit { get; private set; }
		public static bool Is64bit { get; private set; }
		public static bool Is64BitProcess { get { return (IntPtr.Size == 8); } }
		public static bool Is32BitProcess { get { return (IntPtr.Size == 4); } }
		public static string Name { get; private set; }

		[DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)]
		[return: MarshalAs(UnmanagedType.Bool)]
		private static extern bool IsWow64Process([In] IntPtr hProcess, [Out] out bool wow64Process);

		private static bool Is64bitWindows
		{
			get
			{
				if ((Environment.OSVersion.Version.Major == 5 && Environment.OSVersion.Version.Minor >= 1) || Environment.OSVersion.Version.Major >= 6)
				{
					using (Process p = Process.GetCurrentProcess())
					{
						bool retVal;
						if (!IsWow64Process(p.Handle, out retVal))
							return false;
						return retVal;
					}
				}
				else
					return false;
			}
		}

		static CurrentOS()
		{
			IsWindows = Path.DirectorySeparatorChar == '\\';
			if (IsWindows)
			{
				Name = Environment.OSVersion.VersionString;

				Name = Name.Replace("Microsoft ", "");
				Name = Name.Replace("  ", " ");
				Name = Name.Replace(" )", ")");
				Name = Name.Trim();

				Name = Name.Replace("NT 6.2", "8 %bit 6.2");
				Name = Name.Replace("NT 6.1", "7 %bit 6.1");
				Name = Name.Replace("NT 6.0", "Vista %bit 6.0");
				Name = Name.Replace("NT 5.", "XP %bit 5.");
				Name = Name.Replace("%bit", (Is64bitWindows ? "64bit" : "32bit"));

				if (Is64bitWindows)
					Is64bit = true;
				else
					Is32bit = true;
			}
			else
			{
				string UnixName = ReadProcessOutput("uname");
				if (UnixName.Contains("Darwin"))
				{
					IsUnix = true;
					IsMac = true;

					Name = "MacOS X " + ReadProcessOutput("sw_vers", "-productVersion");
					Name = Name.Trim();

					string machine = ReadProcessOutput("uname", "-m");
					if (machine.Contains("x86_64"))
						Is64bit = true;
					else
						Is32bit = true;

					Name += " " + (Is32bit ? "32bit" : "64bit");
				}
				else if (UnixName.Contains("Linux"))
				{
					IsUnix = true;
					IsLinux = true;

					Name = ReadProcessOutput("lsb_release", "-d");
					Name = Name.Substring(Name.IndexOf(":") + 1);
					Name = Name.Trim();

					string machine = ReadProcessOutput("uname", "-m");
					if (machine.Contains("x86_64"))
						Is64bit = true;
					else
						Is32bit = true;

					Name += " " + (Is32bit ? "32bit" : "64bit");
				}
				else if (UnixName != "")
					IsUnix = true;
				else
					IsUnknown = true;
			}
		}

		private static string ReadProcessOutput(string name)
		{
			return ReadProcessOutput(name, null);
		}

		private static string ReadProcessOutput(string name, string args)
		{
			try
			{
				Process p = new Process();
				p.StartInfo.UseShellExecute = false;
				p.StartInfo.RedirectStandardOutput = true;
				if (args != null && args != "")
					p.StartInfo.Arguments = " " + args;
				p.StartInfo.FileName = name;
				p.Start();
				// Do not wait for the child process to exit before
				// reading to the end of its redirected stream.
				// p.WaitForExit();
				// Read the output stream first and then wait.
				string output = p.StandardOutput.ReadToEnd();
				p.WaitForExit();
				if (output == null)
					output = "";
				output = output.Trim();
				return output;
			}
			catch
			{
				return "";
			}
		}
	}
}