using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Windows;
using System.Windows.Data;
using System.Windows.Input;
using System.Windows.Media;
using Comal.Classes;
using InABox.Configuration;
using InABox.Core;
using InABox.Logging;
using InABox.Wpf;
using InABox.WPF;
using InABox.WPF.Themes;
using NDesk.Options;
using PRSDesktop;
using Syncfusion.Licensing;
using Path = System.IO.Path;

namespace PRSDesktop
{
    
    /// <summary>
    ///     Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
        public static DatabaseSettings DatabaseSettings;
        public static AutoUpdateSettings AutoUpdateSettings;
        public static Guid EmployeeID = Guid.Empty;
        public static String EmployeeCode = "";
        public static String EmployeeName = "";
        public static String EmployeeEmail = "";

        public static string Profile { get; set; } = "";
        public static bool IsClosing { get; set; } = false;
        public static bool ShouldRestart { get; set; } = false;

        /*/ Guid to ensure that only one instance of PRS is running
        public static Guid AppGuid = Guid.Parse("237E8828-7F5A-4298-B311-CF0FC27882EC");
        private static Mutex AppMutex;*/

        private readonly OptionSet _commandLineParameters = new()
        {
            {
                "profile=",
                "",
                p => { Profile = p; }
            }
        };

        public App()
        {
            SyncfusionLicenseProvider.RegisterLicense(CoreUtils.SyncfusionLicense(SyncfusionVersion.v25_2));
        }

        private void AutoDiscover(Dictionary<string, DatabaseSettings> allsettings)
        {
            var confirm = MessageWindow.ShowYesNo("Try to configure Server Connection Automatically?", "Auto Discover");
            if (confirm)
                try
                {
                    using (new WaitCursor())
                    {
                        AutoDiscoverySettings autodiscover;
                        using (var client = new UdpClient())
                        {
                            client.Client.SendTimeout = 10000;
                            client.Client.ReceiveTimeout = 20000;

                            var requestData = Encoding.ASCII.GetBytes("");
                            var serverEndPoint = new IPEndPoint(IPAddress.Any, 0);
                            client.EnableBroadcast = true;

                            client.Send(requestData, requestData.Length, new IPEndPoint(IPAddress.Broadcast, 8888));

                            var serverResponseData = client.Receive(ref serverEndPoint);
                            var serverResponse = Encoding.ASCII.GetString(serverResponseData);
                            autodiscover = Serialization.Deserialize<AutoDiscoverySettings>(serverResponse);
                            client.Close();
                        }

                        var settings = new DatabaseSettings();
                        settings.IsActive = true;
                        settings.Logo = autodiscover.Logo;
                        settings.Protocol = autodiscover.Protocol;
                        settings.DatabaseType = DatabaseType.Networked;
                        settings.URLs = autodiscover.URLs;
                        settings.LibraryLocation = autodiscover.LibraryLocation;
                        settings.GoogleAPIKey = autodiscover.GoogleAPIKey;

                        allsettings[autodiscover.Name] = settings;
                        new LocalConfiguration<DatabaseSettings>(autodiscover.Name).Save(settings);

                        AutoUpdateSettings = new AutoUpdateSettings
                        {
                            Channel = autodiscover.UpdateChannel,
                            Type = autodiscover.UpdateType,
                            Location = autodiscover.UpdateLocation,
                            Elevated = autodiscover.UpdateAdmin
                        };
                        new LocalConfiguration<AutoUpdateSettings>().Save(AutoUpdateSettings);

                        MessageWindow.ShowMessage($"Server found at {String.Join(";",autodiscover.URLs)}", "Success");
                    }
                }
                catch
                {
                    MessageWindow.ShowMessage("No Server Found", "Not found", image: MessageWindow.WarningImage);
                }
        }

        private void MoveDirectory(string[] source, string target)
        {
            var stack = new Stack<Folders>();
            stack.Push(new Folders(source[0], target));
            while (stack.Count > 0)
            {
                var folders = stack.Pop();
                Directory.CreateDirectory(folders.Target);
                foreach (var file in Directory.GetFiles(folders.Source, "*.*"))
                {
                    var targetFile = Path.Combine(folders.Target, Path.GetFileName(file));
                    if (!File.Exists(targetFile))
                        File.Move(file, targetFile);
                    else
                        File.Delete(file);
                }

                foreach (var folder in Directory.GetDirectories(folders.Source))
                    stack.Push(new Folders(folder, Path.Combine(folders.Target, Path.GetFileName(folder))));
            }

            Directory.Delete(source[0], true);
        }

        public static void SaveDatabaseSettings()
        {
            new LocalConfiguration<DatabaseSettings>(Profile).Save(DatabaseSettings);
        }

        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);
            
            /*AppMutex = new Mutex(false, $"Global\\{AppGuid}");
            // Don't open if PRS is already running.
            if(!AppMutex.WaitOne(0, false))
            {
                Shutdown(0);
                SendToProcesses(Message.Maximise);
                return;
            }*/

            AutoUpdateSettings = new LocalConfiguration<AutoUpdateSettings>().Load();

            var oldPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "Comal.Desktop");
            if (Directory.Exists(oldPath))
                MoveDirectory(new[] { oldPath }, CoreUtils.GetPath());

            ShutdownMode = ShutdownMode.OnExplicitShutdown;

            SetupExceptionHandling();

            MainLogger.AddLogger(new LogFileLogger(CoreUtils.GetPath()));
            Logger.OnLog += MainLogger.Send;

            if (e.Args.Any())
            {
                DatabaseSettings = new DatabaseSettings();
                var extras = _commandLineParameters.Parse(e.Args);
                if (extras.Any())
                {
                    var sw = new StringWriter();
                    sw.WriteLine("Unknown Parameter(s) found:");
                    foreach (var extra in extras)
                        sw.WriteLine("    " + extra);
                    sw.WriteLine();
                    sw.WriteLine("The following parameters are valid:");
                    _commandLineParameters.WriteOptionDescriptions(sw);
                    MessageWindow.ShowMessage(sw.ToString(), "PRS Desktop Startup Options");
                }
            }
            
            bool bSaveSettings = false;
            var allsettings = new LocalConfiguration<DatabaseSettings>().LoadAll();
            
            // Try AutoDiscovery
            if (!allsettings.Any())
                AutoDiscover(allsettings);
            
            // Create Default Database Entry
            if (!allsettings.Any())
            {
                var settings = new DatabaseSettings();
                settings.UserID = "GUEST";
                settings.Password = "guest";
                settings.Autologin = false;
                allsettings["Default"] = settings;
                bSaveSettings = true;
            }

            // Convert Blank Key to "Default"
            if (allsettings.ContainsKey(""))
            {
                var defaultSettings = allsettings[""];
                allsettings.Remove("");
                defaultSettings.IsActive = true;
                allsettings["Default"] = defaultSettings;
                bSaveSettings = true;
            }
            
            // Check and Convert from URL + Port => URLs
            foreach (var key in allsettings.Keys)
            {
                var settings = allsettings[key];
                var oldurl = CoreUtils.GetPropertyValue(settings, "URL") as String;
                var oldport = CoreUtils.GetPropertyValue(settings, "Port");
                if (!String.IsNullOrWhiteSpace(oldurl))
                {
                    bSaveSettings = true;
                    settings.URLs = new String[] { $"{oldurl}:{oldport}" };
                    CoreUtils.SetPropertyValue(settings, "URL", "");
                    CoreUtils.SetPropertyValue(settings, "Port", 0);
                }

                if (settings.URLs != null)
                {
                    var urls = new List<String>();
                    foreach (var url in settings.URLs)
                    {
                        var comps = url.Split(new[] { "://" }, StringSplitOptions.RemoveEmptyEntries);
                        if (comps.Length > 1)
                        {
                            bSaveSettings = true;
                            urls.Add(comps.Last());
                        }
                        else
                            urls.Add(url);
                    }
                    settings.URLs = urls.ToArray();
                }
            }
            
            if (bSaveSettings)
                new LocalConfiguration<DatabaseSettings>().SaveAll(allsettings);

            DatabaseSettings = null;
            if (!string.IsNullOrWhiteSpace(Profile))
            {
                if (allsettings.ContainsKey(Profile))
                    DatabaseSettings = allsettings[Profile];
                else
                    MessageWindow.ShowMessage($"Profile {Profile} does not exist!", "Error");
            }

            if (DatabaseSettings == null)
            {
                var keys = allsettings.Keys.Where(x => allsettings[x].IsActive).ToArray();
                if (keys.Length > 1)
                {
                    var form = new SelectDatabase(allsettings);
                    if (form.ShowDialog() == true)
                    {
                        Profile = form.Database;
                        DatabaseSettings = allsettings[form.Database];
                    }
                    else
                    {
                        Shutdown(1);
                        return;
                    }

                    form = null;
                }
                else
                {
                    Profile = keys.First();
                    DatabaseSettings = allsettings[Profile];
                }
            }
            StartupUri = new Uri("MainWindow.xaml", UriKind.Relative);
        }
        
        private static IEnumerable<string> GetRestartArguments()
        {
            // Skip the first one, because that is the location.
            return Environment.GetCommandLineArgs().Skip(1);
        }

        protected override void OnExit(ExitEventArgs e)
        {
            base.OnExit(e);
            if (ShouldRestart)
            {
                Process.Start(Path.ChangeExtension(ResourceAssembly.Location, ".exe"), GetRestartArguments());
            }
            //AppMutex.ReleaseMutex();
        }

        private void SetupExceptionHandling()
        {
            AppDomain.CurrentDomain.UnhandledException += (s, e) =>
                LogUnhandledException((Exception)e.ExceptionObject, "AppDomain.CurrentDomain.UnhandledException");

            DispatcherUnhandledException += (s, e) =>
            {
                LogUnhandledException(e.Exception, "Application.Current.DispatcherUnhandledException");
                e.Handled = true;
            };
        }

        private class UnhandledException
        {
            private string _message;
            public string Message
            {
                get => _message;
                set
                {
                    _message = value;
                    Hash = GenerateExceptionHash(value);
                }
            }

            public DateTime OriginalTime { get; set; }

            public DateTime LastTime { get; set; }

            public DateTime LastPrinted { get; set; }

            public int Occurences { get; set; }

            public int Hash { get; private set; }
        }

        private static TimeSpan RepeatedExceptionThreshold = TimeSpan.FromSeconds(10);

        private static Queue<UnhandledException> PreviousUnhandledExceptions { get; set; } = new Queue<UnhandledException>();

        private static int GenerateExceptionHash(string message)
        {
            return message.GetHashCode();
        }

        private static void ClearUnhandledExceptions()
        {
            while (PreviousUnhandledExceptions.TryPeek(out var e) && DateTime.Now - e.LastTime > RepeatedExceptionThreshold)
            {
                PreviousUnhandledExceptions.Dequeue();
            }
        }

        private void LogUnhandledException(Exception exception, string source)
        {
            ClearUnhandledExceptions();
            
            var messages = new List<string>();
            var e2 = exception;
            while (e2 != null)
            {
                messages.InsertRange(0, new[] { e2.Message, e2.StackTrace, "============================================" });
                e2 = e2.InnerException;
            }

            var unhandled = new UnhandledException
            {
                Message = string.Join("\n", messages),
                OriginalTime = DateTime.Now,
                Occurences = 1
            };
            unhandled.LastTime = unhandled.OriginalTime;
            unhandled.LastPrinted = unhandled.OriginalTime;

            UnhandledException? found = null;
            foreach(var e in PreviousUnhandledExceptions)
            {
                if(e.Hash == unhandled.Hash)
                {
                    e.LastTime = unhandled.LastTime;
                    e.Occurences++;
                    found = e;
                    break;
                }
            }
            if (found is null)
            {
                PreviousUnhandledExceptions.Enqueue(unhandled);
                MainLogger.Send(LogType.Error, "", string.Join("\n", messages), Guid.Empty);
            }
            else
            {
                if((DateTime.Now - found.LastPrinted).TotalSeconds >= 1)
                {
                    MainLogger.Send(LogType.Error, "", $"Recurrent Error occurred {found.Occurences} times; See {found.OriginalTime}", Guid.Empty);
                    found.LastPrinted = DateTime.Now;
                }
            }


            // if (exception.Message.StartsWith("Dispatcher processing has been suspended"))
            //     try
            //     {
            //         SendKeys.Send("{ESC}");
            //     }
            //     catch (Exception e)
            //     {
            //     }
        }

        private class Folders
        {
            public Folders(string source, string target)
            {
                Source = source;
                Target = target;
            }

            public string Source { get; }

            public string Target { get; }
        }
        /*
        public enum Message
        {
            Maximise = 0x2A76
        }

        private void SendToProcesses(Message message)
        {
            var process = Process.GetCurrentProcess();
            var processes = Process.GetProcessesByName(process.ProcessName);
            if(processes.Length > 1)
            {
                foreach(var p in processes)
                {
                    if(p.Id != process.Id)
                    {
                        SendMessage(p.MainWindowHandle, (uint)message, IntPtr.Zero, IntPtr.Zero);
                    }
                }
            }
        }

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr SendMessage(IntPtr hwnd, uint Msg, IntPtr wParam, IntPtr lParam);
        */
    }
}