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

using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;
using System;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Reflection.PortableExecutable;
using System.Threading;

namespace Microsoft.DotNet.Arcade.Sdk;

[MSBuildMultiThreadableTask]
public class Unsign : Task, IMultiThreadableTask
{
    /// <summary>Injected by MSBuild so paths resolve against the project directory in multithreaded builds.</summary>
    public TaskEnvironment TaskEnvironment { get; set; } = TaskEnvironment.Fallback;

    [Required]
    public string FilePath { get; set; }

    public override bool Execute()
    {
        try
        {
            ExecuteImpl();
            return !Log.HasLoggedErrors;
        }
        finally
        {
        }
    }

    private void ExecuteImpl()
    {
        using (var stream = File.Open(TaskEnvironment.GetAbsolutePath(FilePath), FileMode.Open, FileAccess.ReadWrite, FileShare.Read))
        using (var peReader = new PEReader(stream))
        {
            var headers = peReader.PEHeaders;
            var entry = headers.PEHeader.CertificateTableDirectory;
            if (entry.Size == 0)
            {
                return;
            }

            using (var writer = new BinaryWriter(stream))
            {
                int certificateTableDirectoryOffset = (headers.PEHeader.Magic == PEMagic.PE32Plus) ? 144 : 128;
                stream.Position = peReader.PEHeaders.PEHeaderStartOffset + certificateTableDirectoryOffset;

                writer.Write((long)0);
                writer.Flush();
            }
        }
    }
}