// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Runtime.Versioning;
using Microsoft.Win32.SafeHandles;
 
namespace Aspire.Shared;
 
internal static partial class ProcessSupervisor
{
    [SupportedOSPlatform("windows")]
    private static unsafe SafeWaitHandle CreateWindowsJob()
    {
        var handle = CreateJobObjectW(IntPtr.Zero, null);
        if (handle == IntPtr.Zero)
        {
            throw new Win32Exception(Marshal.GetLastPInvokeError(), "Could not create the supervised process job.");
        }
        var job = new SafeWaitHandle(handle, ownsHandle: true);
        var limits = new ExtendedLimitInformation
        {
            BasicLimitInformation = new BasicLimitInformation { LimitFlags = 0x2000 }
        };
        // Enroll the guardian before launching the runtime, avoiding the race where
        // a package-manager lifecycle script creates children before job enrollment.
        // No breakaway flag: workers must not escape the owner's lifetime.
        // https://learn.microsoft.com/windows/win32/procthread/job-objects
        if (!SetInformationJobObject(job, 9, &limits, (uint)sizeof(ExtendedLimitInformation)) ||
            !AssignProcessToJobObject(job, new IntPtr(-1)))
        {
            var error = Marshal.GetLastPInvokeError();
            job.Dispose();
            throw new Win32Exception(error, "Could not contain the process supervisor in its job.");
        }
 
        return job;
    }
 
    [LibraryImport("kernel32.dll", SetLastError = true, StringMarshalling = StringMarshalling.Utf16)]
    private static partial IntPtr CreateJobObjectW(IntPtr attributes, string? name);
 
    [LibraryImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static partial bool AssignProcessToJobObject(SafeWaitHandle job, IntPtr process);
 
    [LibraryImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static unsafe partial bool SetInformationJobObject(SafeWaitHandle job, int informationClass, void* information, uint length);
 
    [StructLayout(LayoutKind.Sequential)]
    private struct BasicLimitInformation
    {
        public long PerProcessUserTimeLimit;
        public long PerJobUserTimeLimit;
        public uint LimitFlags;
        public nuint MinimumWorkingSetSize;
        public nuint MaximumWorkingSetSize;
        public uint ActiveProcessLimit;
        public nuint Affinity;
        public uint PriorityClass;
        public uint SchedulingClass;
    }
 
    [StructLayout(LayoutKind.Sequential)]
    private struct IoCounters
    {
        public ulong ReadOperationCount;
        public ulong WriteOperationCount;
        public ulong OtherOperationCount;
        public ulong ReadTransferCount;
        public ulong WriteTransferCount;
        public ulong OtherTransferCount;
    }
 
    [StructLayout(LayoutKind.Sequential)]
    private struct ExtendedLimitInformation
    {
        public BasicLimitInformation BasicLimitInformation;
        public IoCounters IoInfo;
        public nuint ProcessMemoryLimit;
        public nuint JobMemoryLimit;
        public nuint PeakProcessMemoryUsed;
        public nuint PeakJobMemoryUsed;
    }
}