using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Tango.Core.Helpers;
using Tango.Logging;
using Tango.PPC.Common.WatchDog;
using Tango.SharedUI;
using Tango.SharedUI.Components;

namespace Tango.PPC.WatchDog
{
    public class MainWindowVM : ViewModel
    {
        [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
        static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName);

        private const String tango_process_name = "Tango.PPC.UI";
        private WatchDogClient _watchdog;
        public TextController Log { get; set; }

        public MainWindowVM()
        {
            var logger = new SimpleStringLogger();
            logger.LogReceived += Logger_LogReceived;
            LogManager.RegisterLogger(logger);

            _watchdog = new WatchDogClient();
            _watchdog.ServerNotResponding += _watchdog_ServerNotResponding;
            Log = new TextController();

            _watchdog.Start();
        }

        private void Logger_LogReceived(object sender, LogItemBase e)
        {
            if (e is ExceptionLogItem)
            {
                Log.WriteLine(e.ToString());
            }
            else
            {
                Log.WriteLine($"[{e.TimeStamp.ToString()}] {e.Message}");
            }
        }

        private void _watchdog_ServerNotResponding(object sender, EventArgs e)
        {
            LogManager.Log("PPC application failed to respond!", LogCategory.Warning);
            LogManager.Log("Ensuring PPC application is down...");

            var appProcess = Process.GetProcessesByName(tango_process_name).FirstOrDefault();
            Process p = new Process();
            p.StartInfo.CreateNoWindow = true;
            p.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
            p.StartInfo.FileName = "wmic";
            p.StartInfo.Arguments = String.Format("process where name='{0}' delete", tango_process_name);

            try
            {
                if (appProcess != null)
                {
                    LogManager.Log("PPC application process found and seems to be frozen. Trying to kill the process...");
                    appProcess.Kill();

                    appProcess = Process.GetProcessesByName(tango_process_name).FirstOrDefault();

                    if (appProcess != null)
                    {
                        LogManager.Log("Process kill failed. Trying again...");
                        p.Start();
                        Thread.Sleep(2000);

                        appProcess = Process.GetProcessesByName(tango_process_name).FirstOrDefault();

                        if (appProcess == null)
                        {
                            LogManager.Log("PPC application is down.");
                        }
                    }
                    else
                    {
                        LogManager.Log("PPC application is down.");
                    }
                }
            }
            catch
            {
                try
                {
                    LogManager.Log("Process kill failed. Trying again...");
                    p.Start();
                    Thread.Sleep(2000);

                    appProcess = Process.GetProcessesByName(tango_process_name).FirstOrDefault();

                    if (appProcess == null)
                    {
                        LogManager.Log("PPC application is down.");
                    }
                }
                catch { }
            }

            LogManager.Log("Restarting PPC application...");

            try
            {
                var process = Process.Start(Path.Combine(AssemblyHelper.GetCurrentAssemblyFolder(), tango_process_name + ".exe"));
                LogManager.Log("PPC application started.");
                LogManager.Log("Waiting for the application main window....");
                if (WaitForPPCWindow(TimeSpan.FromSeconds(5), TimeSpan.FromMinutes(1)))
                {
                    LogManager.Log("Application main window opened. waiting another 10 seconds...");
                    Thread.Sleep(TimeSpan.FromSeconds(10));
                    _watchdog.Start();
                }
                else
                {
                    LogManager.Log("The PPC application main window has failed to open within 1 minute. The Watchdog will not start again!");
                }
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error starting PPC application.");
            }
        }

        private bool WaitForPPCWindow(TimeSpan interval, TimeSpan timeout)
        {
            for (TimeSpan time = TimeSpan.Zero; time < timeout; time = time.Add(interval))
            {
                IntPtr windowPtr = FindWindowByCaption(IntPtr.Zero, "Tango - PPC");
                if (windowPtr != IntPtr.Zero)
                {
                    return true;
                }

                Thread.Sleep(interval);
            }

            return false;
        }
    }
}