// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
#nullable disable
 
using System;
using System.Runtime.InteropServices;
using System.Security;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.Interop
{
    internal static class ClrStrongName
    {
        [DllImport("mscoree.dll", PreserveSig = false, EntryPoint = "CLRCreateInstance")]
        [return: MarshalAs(UnmanagedType.Interface)]
        private static extern object nCreateInterface(
                [MarshalAs(UnmanagedType.LPStruct)] Guid clsid,
                [MarshalAs(UnmanagedType.LPStruct)] Guid riid);
 
        internal static IClrStrongName GetInstance()
        {
            var metaHostClsid = new Guid(unchecked((int)0x9280188D), 0xE8E, 0x4867, 0xB3, 0xC, 0x7F, 0xA8, 0x38, 0x84, 0xE8, 0xDE);
            var metaHostGuid = new Guid(unchecked((int)0xD332DB9E), unchecked((short)0xB9B3), 0x4125, 0x82, 0x07, 0xA1, 0x48, 0x84, 0xF5, 0x32, 0x16);
            var clrStrongNameClsid = new Guid(unchecked((int)0xB79B0ACD), unchecked((short)0xF5CD), 0x409b, 0xB5, 0xA5, 0xA1, 0x62, 0x44, 0x61, 0x0B, 0x92);
            var clrRuntimeInfoGuid = new Guid(unchecked((int)0xBD39D1D2), unchecked((short)0xBA2F), 0x486A, 0x89, 0xB0, 0xB4, 0xB0, 0xCB, 0x46, 0x68, 0x91);
            var clrStrongNameGuid = new Guid(unchecked((int)0x9FD93CCF), 0x3280, 0x4391, 0xB3, 0xA9, 0x96, 0xE1, 0xCD, 0xE7, 0x7C, 0x8D);
 
            var metaHost = (IClrMetaHost)nCreateInterface(metaHostClsid, metaHostGuid);
            var runtime = (IClrRuntimeInfo)metaHost.GetRuntime(GetRuntimeVersion(), clrRuntimeInfoGuid);
            return (IClrStrongName)runtime.GetInterface(clrStrongNameClsid, clrStrongNameGuid);
        }
 
        internal static string GetRuntimeVersion()
        {
            // When running in a complus environment we must respect the specified CLR version.  This 
            // important to keeping internal builds running. 
            if (!string.IsNullOrEmpty(Environment.GetEnvironmentVariable("COMPLUS_InstallRoot")))
            {
                var version = Environment.GetEnvironmentVariable("COMPLUS_Version");
                if (!string.IsNullOrEmpty(version))
                {
                    return version;
                }
            }
 
            return "v4.0.30319";
        }
    }
}