using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace RoboSharp
{
#pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
    /// <summary>
    /// Native Methods for Pause/Suspend/Resume processes
    /// </summary>
    public static class NativeMethods
    {
        [Flags]
        public enum ThreadAccess : int
        {
            TERMINATE = (0x0001),
            SUSPEND_RESUME = (0x0002),
            GET_CONTEXT = (0x0008),
            SET_CONTEXT = (0x0010),
            SET_INFORMATION = (0x0020),
            QUERY_INFORMATION = (0x0040),
            SET_THREAD_TOKEN = (0x0080),
            IMPERSONATE = (0x0100),
            DIRECT_IMPERSONATION = (0x0200)
        }

        [DllImport("kernel32.dll")]
        static extern IntPtr OpenThread(ThreadAccess dwDesiredAccess, bool bInheritHandle, uint dwThreadId);
        [DllImport("kernel32.dll")]
        static extern uint SuspendThread(IntPtr hThread);
        [DllImport("kernel32.dll")]
        static extern int ResumeThread(IntPtr hThread);

        public static bool Suspend(this Process process)
        {
            if (process.HasExited) return false;
            foreach (ProcessThread thread in process.Threads)
            {
                var pOpenThread = OpenThread(ThreadAccess.SUSPEND_RESUME, false, (uint)thread.Id);
                if (pOpenThread == IntPtr.Zero)
                {
                    break;
                }
                SuspendThread(pOpenThread);
            }
            return true;
        }
        public static bool Resume(this Process process)
        {
            if (process.HasExited) return false;
            foreach (ProcessThread thread in process.Threads)
            {
                var pOpenThread = OpenThread(ThreadAccess.SUSPEND_RESUME, false, (uint)thread.Id);
                if (pOpenThread == IntPtr.Zero)
                {
                    break;
                }
                ResumeThread(pOpenThread);
            }
            return true;
        }
    }
#pragma warning restore CS1591 // Missing XML comment for publicly visible type or member
}