// Copyright (c) Microsoft Corporation
// The Microsoft Corporation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Diagnostics;
using System.Reflection;
using System.Threading.Tasks;
using Microsoft.PowerToys.Telemetry;
using Microsoft.PowerToys.Telemetry.Events;

namespace ManagedCommon
{
    public static class RunnerHelper
    {
        public static void WaitForPowerToysRunner(int powerToysPID, Action act)
        {
            var stackTrace = new StackTrace();
            var assembly = Assembly.GetCallingAssembly().GetName();
            var callingMethod = stackTrace.GetFrame(1).GetMethod().Name;
            PowerToysTelemetry.Log.WriteEvent(new DebugEvent() { Message = $"[{assembly}][{callingMethod}]WaitForPowerToysRunner waiting for Event powerToysPID={powerToysPID}" });
            Task.Run(() =>
            {
                const uint INFINITE = 0xFFFFFFFF;
                const uint WAIT_OBJECT_0 = 0x00000000;
                const uint SYNCHRONIZE = 0x00100000;

                IntPtr powerToysProcHandle = NativeMethods.OpenProcess(SYNCHRONIZE, false, powerToysPID);
                if (NativeMethods.WaitForSingleObject(powerToysProcHandle, INFINITE) == WAIT_OBJECT_0)
                {
                    PowerToysTelemetry.Log.WriteEvent(new DebugEvent() { Message = $"[{assembly}][{callingMethod}]WaitForPowerToysRunner Event Notified powerToysPID={powerToysPID}" });
                    act.Invoke();
                }
            });
        }

        private static readonly string PowerToysRunnerProcessName = "PowerToys.exe";

        // In case we don't have a permission to open user's processes with a SYNCHRONIZE access right, e.g. LocalSystem processes, we could use GetExitCodeProcess to check the process' exit code periodically.
        public static void WaitForPowerToysRunnerExitFallback(Action act)
        {
            int[] processIds = new int[1024];
            uint bytesCopied;

            NativeMethods.EnumProcesses(processIds, (uint)processIds.Length * sizeof(uint), out bytesCopied);

            const uint PROCESS_QUERY_LIMITED_INFORMATION = 0x1000;
            var handleAccess = PROCESS_QUERY_LIMITED_INFORMATION;

            IntPtr runnerHandle = IntPtr.Zero;
            foreach (var processId in processIds)
            {
                IntPtr hProcess = NativeMethods.OpenProcess(handleAccess, false, processId);
                System.Text.StringBuilder name = new System.Text.StringBuilder(1024);
                uint length = 1024;
                if (hProcess == IntPtr.Zero || !NativeMethods.QueryFullProcessImageName(hProcess, 0, name, ref length))
                {
                    continue;
                }

                if (System.IO.Path.GetFileName(name.ToString()) == PowerToysRunnerProcessName)
                {
                    runnerHandle = hProcess;
                    break;
                }
            }

            if (runnerHandle == IntPtr.Zero)
            {
                Logger.LogError("Couldn't determine PowerToys.exe pid");
                return;
            }

            Task.Run(() =>
            {
                const int STILL_ACTIVE = 0x103;
                uint exit_status;
                do
                {
                    System.Threading.Thread.Sleep(1000);
                    NativeMethods.GetExitCodeProcess(runnerHandle, out exit_status);
                }
                while (exit_status == STILL_ACTIVE);

                NativeMethods.CloseHandle(runnerHandle);

                act.Invoke();
            });
        }
    }
}
