using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

namespace WebApplication6

{

    public class CurrentDirectoryHelpers

    {

        internal const string AspNetCoreModuleDll = "aspnetcorev2_inprocess.dll";

        [System.Runtime.InteropServices.DllImport("kernel32.dll")]

        private static extern IntPtr GetModuleHandle(string lpModuleName);

        [System.Runtime.InteropServices.DllImport(AspNetCoreModuleDll)]

        private static extern int http_get_application_properties(ref IISConfigurationData iiConfigData);

        [System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)]

        private struct IISConfigurationData

        {

            public IntPtr pNativeApplication;

            [System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.BStr)]

            public string pwzFullApplicationPath;

            [System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.BStr)]

            public string pwzVirtualApplicationPath;

            public bool fWindowsAuthEnabled;

            public bool fBasicAuthEnabled;

            public bool fAnonymousAuthEnable;

        }

        public static void SetCurrentDirectory()

        {

            try

            {

                // Check if physical path was provided by ANCM

                var sitePhysicalPath = Environment.GetEnvironmentVariable("ASPNETCORE_IIS_PHYSICAL_PATH");

                if (string.IsNullOrEmpty(sitePhysicalPath))

                {

                    // Skip if not running ANCM InProcess

                    if (GetModuleHandle(AspNetCoreModuleDll) == IntPtr.Zero)

                    {

                        return;

                    }

                    IISConfigurationData configurationData = default(IISConfigurationData);

                    if (http_get_application_properties(ref configurationData) != 0)

                    {

                        return;

                    }

                    sitePhysicalPath = configurationData.pwzFullApplicationPath;

                }

                Environment.CurrentDirectory = sitePhysicalPath;

            }

            catch

            {

                // ignore

            }

        }

    }

}