#region --- License ---
/* Licensed under the MIT/X11 license.
 * Copyright (c) 2006-2008 the OpenTK Team.
 * This notice may not be removed from any source distribution.
 * See license.txt for licensing detailed licensing details.
 */
#endregion

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

[assembly: CLSCompliant(true)]
[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("OpenTK.Utilities")]

namespace OpenTK
{
    /// <internal />
    /// <summary>Contains configuration options for OpenTK.</summary>
    internal static class Configuration
    {
        static bool runningOnWindows, runningOnX11, runningOnMacOS, runningOnLinux;

        #region --- Constructors ---

        static Configuration()
        {
            if (System.Environment.OSVersion.Platform == PlatformID.Win32NT ||
                System.Environment.OSVersion.Platform == PlatformID.Win32S ||
                System.Environment.OSVersion.Platform == PlatformID.Win32Windows ||
                System.Environment.OSVersion.Platform == PlatformID.WinCE)
                runningOnWindows = true;
            else if (System.Environment.OSVersion.Platform == PlatformID.Unix ||
                     System.Environment.OSVersion.Platform == (PlatformID)4)
            {
                // Distinguish between Unix and Mac OS X kernels.
                switch (DetectUnixKernel())
                {
                    case "Unix":
                    case "Linux":
                        runningOnX11 = true;
                        break;

                    case "Darwin":
                        runningOnMacOS = true;
                        break;

                    default:
                        throw new PlatformNotSupportedException(
                            DetectUnixKernel() + ": Unknown Unix platform. Please report this error at http://www.opentk.com.");
                }
            }
            else
                throw new PlatformNotSupportedException("Unknown platform. Please report this error at http://www.opentk.com.");
        }

        #endregion

        #region --- Public Methods ---

        #region internal static bool RunningOnWindows

        /// <summary>Gets a System.Boolean indicating whether OpenTK is running on a Windows platform.</summary>
        internal static bool RunningOnWindows { get { return runningOnWindows; } }

        #endregion

        #region internal static bool RunningOnX11

        /// <summary>Gets a System.Boolean indicating whether OpenTK is running on an X11 platform.</summary>
        internal static bool RunningOnX11 { get { return runningOnX11; } }

        #endregion

        #region internal static bool RunningOnLinux

        /// <summary>Gets a System.Boolean indicating whether OpenTK is running on an X11 platform.</summary>
        internal static bool RunningOnLinux { get { return runningOnLinux; } }

        #endregion

        #region internal static bool RunningOnMacOS

        /// <summary>Gets a System.Boolean indicating whether OpenTK is running on a Mac OS platform.</summary>
        internal static bool RunningOnMacOS { get { return runningOnMacOS; } }

        #endregion

        #region --- Private Methods ---

        #region private static string DetectUnixKernel()

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
        struct utsname
        {
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string sysname;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string nodename;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string release;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string version;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string machine;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 1024)]
            public string extraJustInCase;

        }

        private static string DetectUnixKernel()
        {
            Debug.Print("Size: {0}", Marshal.SizeOf(typeof(utsname)).ToString());
            Debug.Flush();
            utsname uts = new utsname();
            uname(out uts);

            Debug.WriteLine("System:");
            Debug.Indent();
            Debug.WriteLine(uts.sysname);
            Debug.WriteLine(uts.nodename);
            Debug.WriteLine(uts.release);
            Debug.WriteLine(uts.version);
            Debug.WriteLine(uts.machine);
            Debug.Unindent();

            return uts.sysname.ToString();
        }

        [DllImport("libc")]
        private static extern void uname(out utsname uname_struct);


        /// <summary>
        /// Executes "uname" which returns a string representing the name of the
        /// underlying Unix kernel.
        /// </summary>
        /// <returns>"Unix", "Linux", "Darwin" or null.</returns>
        /// <remarks>Source code from "Mono: A Developer's Notebook"</remarks>
        private static string oldDetectUnixKernel()
        {
            ProcessStartInfo startInfo = new ProcessStartInfo();
            startInfo.Arguments = "-s";
            startInfo.RedirectStandardOutput = true;
            startInfo.RedirectStandardError = true;
            startInfo.UseShellExecute = false;
            foreach (string unameprog in new string[] { "/usr/bin/uname", "/bin/uname", "uname" })
            {
                try
                {
                    startInfo.FileName = unameprog;
                    Process uname = Process.Start(startInfo);
                    StreamReader stdout = uname.StandardOutput;
                    return stdout.ReadLine().Trim();
                }
                catch (System.IO.FileNotFoundException)
                {
                    // The requested executable doesn't exist, try next one.
                    continue;
                }
                catch (System.ComponentModel.Win32Exception)
                {
                    continue;
                }
            }
            return null;
        }

        #endregion

        #endregion

        #endregion
    }
}