// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.Marshalling;

namespace Microsoft.DotNet.Build.Tasks.Feed;

internal partial class NativeMethods
{
    [LibraryImport("kernel32.dll", EntryPoint = "CreateHardLinkW", SetLastError = true, StringMarshalling = StringMarshalling.Utf16)]
    [return: MarshalAs(UnmanagedType.Bool)]
    internal static partial bool CreateHardLink(string newFileName, string exitingFileName, IntPtr securityAttributes);

    [LibraryImport("libc", SetLastError = true, StringMarshalling = StringMarshalling.Utf16)]
    internal static partial int link(string oldpath, string newpath);

    internal static bool MakeHardLink(string newFileName, string exitingFileName, ref string errorMessage)
    {
        bool hardLinkCreated;
        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
        {
            hardLinkCreated = CreateHardLink(newFileName, exitingFileName, IntPtr.Zero /* reserved, must be NULL */);
            errorMessage = hardLinkCreated ? null : Marshal.GetExceptionForHR(Marshal.GetHRForLastWin32Error()).Message;
        }
        else
        {
            hardLinkCreated = link(exitingFileName, newFileName) == 0;
            errorMessage = hardLinkCreated ? null : $"The link() library call failed with the following error code: {Marshal.GetLastWin32Error()}.";
        }

        return hardLinkCreated;
    }
}