using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography.X509Certificates;
using System.Timers;
using Comal.Classes;
using Comal.Stores;
using InABox.API;
using InABox.Configuration;
using InABox.Core;
using InABox.Database;
using InABox.Database.SQLite;
using InABox.IPC;
using InABox.Rpc;
using InABox.Server;
using InABox.Wpf.Reports;
using PRS.Shared;
using Timer = System.Timers.Timer;

namespace PRSServer
{
    public class DatabaseEngine : Engine<DatabaseServerProperties>
    {
        private Timer? CertificateRefreshTimer;
        private Timer? CertificateHaltTimer;
        private string PipeName;
        //private IPCServer? PipeServer;

        private IRpcServer? _pipeserver;
        private IRpcServer? _socketserver;
        
        public override void Configure(Server server)
        {
            base.Configure(server);
            Logger.Send(LogType.Information, "", "Configuring...");

            PipeName = DatabaseServerProperties.GetPipeName(server.Key);
            MoveUpdateFiles();
        }

        public override PortStatus[] PortStatusList()
        {
            var result = new List<PortStatus>();
            if (Properties.Port != 0)
            {
                if (RestListener.Certificate != null)
                    result.Add(new PortStatus(Properties.Port, PortType.Database, PortState.Secure));
                else 
                    result.Add(new PortStatus(Properties.Port, PortType.Database, PortState.Available));
            }
            if (Properties.WebSocketPort != 0)
                result.Add(new PortStatus(Properties.WebSocketPort, PortType.Session, PortState.Available));
            return result.ToArray();
        }

        private void ConfigureSMSProviders()
        {
            if(Properties.SMSProviderProperties == null) return;
            if(Properties.SMSProviderProperties.Count == 0)
            {
                Logger.Send(LogType.Information, "", "No SMS Providers to initialise");
            }
            foreach(var (type, properties) in Properties.SMSProviderProperties)
            {
                var provider = SMSProviderProperties.ToProperties(type, properties);
                switch (provider)
                {
                    case ExchangeProviderProperties exchange:
                        Logger.Send(LogType.Information, "", string.Format("Initializing Exchange Mailer", Properties.Port));
                        CredentialsCache.AddSMSProvider(new ExchangeProvider(
                            exchange.Host,
                            exchange.Port,
                            exchange.EmailAddress,
                            exchange.Password
                        ));
                        break;
                    case IMAPProviderProperties imap:
                        Logger.Send(LogType.Information, "", string.Format("Initializing IMAP Mailer", Properties.Port));
                        CredentialsCache.AddSMSProvider(new IMAPProvider(
                            imap.Host,
                            imap.Port,
                            imap.EmailAddress,
                            imap.Password
                        ));
                        break;
                    case ASPSMSProviderProperties asp:
                        Logger.Send(LogType.Information, "", string.Format("Initializing ASPSMS", Properties.Port));
                        CredentialsCache.AddSMSProvider(new ASPSMSProvider(
                            asp.Userkey,
                            asp.APIPassword
                        ));
                        break;
                    case TwilioProviderProperties tw:
                        Logger.Send(LogType.Information, "", string.Format("Initializing Twilio", Properties.Port));
                        CredentialsCache.AddSMSProvider(new TwilioSMSProvider(
                            tw.AccountSID,
                            tw.AuthToken,
                            tw.Number
                        ));
                        break;
                }
            }
        }

        private IEnumerable<Notification> PollNotifications(Guid session)
        {
            var user = CredentialsCache.Validate(session);
            if (user == null)
                return Array.Empty<Notification>();
            var store = DbFactory.FindStore<Notification>(user.ID, user.UserID, Platform.DatabaseEngine, "");
            return store.Query(
                new Filter<Notification>(x => x.Employee.UserLink.ID).IsEqualTo(user.ID)
                    .And(x => x.Closed).IsEqualTo(DateTime.MinValue),
                new Columns<Notification>(
                    x => x.ID,
                    x => x.Title,
                    //x => x.Description,
                    x => x.Created,
                    x => x.Sender.ID,
                    x => x.Sender.Name,
                    x => x.Job.ID,
                    x => x.Job.Deleted,
                    x => x.Job.JobNumber,
                    //x => x.Kanban.ID,
                    //x => x.Setout.ID,
                    //x => x.Requisition.ID,
                    //x => x.Delivery.ID,
                    x => x.Employee.ID,
                    x => x.EntityType,
                    x => x.EntityID,
                    x => x.Closed
                )).Rows.Select(x => x.ToObject<Notification>());
        }

        private void ConfigurePusher()
        {
            PushManager.AddPollHandler(PollNotifications);
        }

        public override void Run()
        {
            Logger.Send(LogType.Information, "", "Starting..");


            if (Properties.Port.Equals(0))
                throw new Exception("Error: Port not Specified\n");

            if (string.IsNullOrEmpty(Properties.FileName))
                throw new Exception("Error: Filename not Specified\n");

            Logger.Send(LogType.Information, "", "Registering Classes: " + Properties.FileName);

            StoreUtils.RegisterClasses();
            CoreUtils.RegisterClasses();
            ComalUtils.RegisterClasses();
            ReportUtils.RegisterClasses();
            ConfigurationUtils.RegisterClasses();

            DatabaseUpdateScripts.RegisterScripts();

            Logger.Send(LogType.Information, "", "Starting Database: " + Properties.FileName);

            DbFactory.Stores = CoreUtils.TypeList(
                AppDomain.CurrentDomain.GetAssemblies(),
                myType =>
                    myType.IsClass
                    && !myType.IsAbstract
                    && !myType.IsGenericType
                    && myType.GetInterfaces().Contains(typeof(IStore))
            ).ToArray();

            DbFactory.Provider = new SQLiteProvider(Properties.FileName);

            DbFactory.ColorScheme = Properties.ColorScheme;
            DbFactory.Logo = Properties.Logo;

            DbFactory.Start();
            
            UserStore.PasswordExpirationTime = TimeSpan.FromDays(Properties.PasswordExpiryTime);
            RestService.CheckPasswordExpiration = Properties.PasswordExpiryTime > 0;

            var users = DbFactory.Provider.Load<User>();
            if (!users.Any())
            {
                var user = new User { UserID = "ADMIN", Password = "admin" };
                DbFactory.Provider.Save(user);

                var employee = DbFactory.Provider.Load(new Filter<Employee>(x => x.Code).IsEqualTo("ADMIN")).FirstOrDefault();
                if (employee == null)
                    employee = new Employee { Code = "ADMIN", Name = "Administrator Account" };
                employee.UserLink.ID = user.ID;
                DbFactory.Provider.Save(employee);
            }

            StoreUtils.GoogleAPIKey = Properties.GoogleAPIKey;
            PurchaseOrderStore.AutoIncrementPrefix = Properties.PurchaseOrderPrefix;
            JobStore.AutoIncrementPrefix = Properties.JobPrefix;

            ConfigureSMSProviders();
            CredentialsCache.SetCacheFile(Path.Combine(AppDataFolder, "session_cache.json"));
            CredentialsCache.LoadSessionCache();
            CredentialsCache.SetSessionExpiryTime(TimeSpan.FromMinutes(Properties.SessionExpiryTime));

            // if (Properties.WebSocketPort != 0)
            // {
            //     // Put a log saying to start the web socket listener.
            //     Logger.Send(LogType.Information, "", string.Format("Starting Web Socket Listener: Port={0}", Properties.WebSocketPort));
            // }
            // // This should be out of the if-statement, since the listener needs to be initialised, even if the web socket port is 0.
            // RestListener.Init(Properties.WebSocketPort);
            // InitialisePort();
            // RestListener.Start();

            Logger.Send(LogType.Information, "", string.Format("Starting Web Listener: Port={0}", Properties.Port));

            var sockettransport = new RpcServerSocketTransport(Properties.Port, CertificateFileName());
            _socketserver = new RpcServer<RpcServerSocketTransport>(sockettransport);
            _socketserver.OnLog += (type, userid, message, parameters) => Logger.Send(type, userid, $"[S] {message}", parameters);
            _socketserver.Start();
            PushManager.AddPusher(sockettransport);

            Logger.Send(LogType.Information, "", string.Format("Server started listening on port {0}", Properties.Port));

            // PipeServer = new IPCServer(PipeName);
            // PipeServer.Start();

            Logger.Send(LogType.Information, "", $"Starting Pipe Listener with pipe name {PipeName}");
            var pipetransport = new RpcServerPipeTransport(PipeName);
            _pipeserver = new RpcServer<RpcServerPipeTransport>(pipetransport);
            _pipeserver.OnLog += (type, userid, message, parameters) => Logger.Send(type, userid, $"[P] {message}", parameters);
            _pipeserver.Start();
            PushManager.AddPusher(pipetransport);

            Logger.Send(LogType.Information, "", "Pipe Listener started");
            
            ConfigurePusher();

        }

        #region Certificate Management

        private string CertificateFileName() => 
            !string.IsNullOrWhiteSpace(Properties.CertificateFile) 
            ? Properties.CertificateFile
            : CertificateEngine.CertificateFile;

        private void InitialisePort()
        {
            var useHTTP = true;
            if (File.Exists(CertificateFileName()))
            {
                Logger.Send(LogType.Information, "", "Certificate found; verifying HTTPS Certificate");
                try
                {
                    var certificate = new X509Certificate2(CertificateFileName());
                    if (certificate.NotAfter > DateTime.Now)
                    {
                        RestListener.InitCertificate((ushort)Properties.Port, certificate);

                        var names = CertificateEngine.GetDnsNames(certificate);
                        Logger.Send(LogType.Information, "", $"Certificate valid for {string.Join(',', names)}");
                        useHTTP = false;
                    }
                    else
                    {
                        Logger.Send(LogType.Error, "", "HTTPS Certificate has expired, using HTTP instead");
                    }
                }
                catch (Exception)
                {
                    Logger.Send(LogType.Error, "", "Error validating HTTPS Certificate, using HTTP instead");
                }
            }
            if (useHTTP)
            {
                RestListener.InitPort((ushort)Properties.Port);
            }
            else
            {
                // Once every day, check certificate expiry
                if(CertificateRefreshTimer == null)
                {
                    CertificateRefreshTimer = new Timer(1000 * 60 * 60 * 24);
                    CertificateRefreshTimer.Elapsed += CertificateTimer_Elapsed;
                    CertificateRefreshTimer.AutoReset = true;
                }
                CertificateRefreshTimer.Start();
            }
        }

        private void SendCertificateExpiryNotification(DateTime expiry)
        {
            string message;
            if (expiry.Date == DateTime.Now.Date)
            {
                message = $"HTTPS Certificate for Database Engine will expire today at {expiry.TimeOfDay:hh\\:mm}";
            }
            else
            {
                message = $"HTTPS Certificate for Database Engine will expire in {(expiry - DateTime.Now).Days} at {expiry:dd/MM/yyyy hh:mm}";
            }
            Logger.Send(LogType.Information, "DATABASE", message);
            if (!string.IsNullOrWhiteSpace(Properties.CertificateExpirationSubscriber))
            {
                var employee = DbFactory.Provider.Query(
                    new Filter<Employee>(x => x.UserLink.UserID).IsEqualTo(Properties.CertificateExpirationSubscriber),
                    new Columns<Employee>(x => x.ID, x => x.UserLink.ID, x => x.UserLink.UserID)).Rows.FirstOrDefault()?.ToObject<Employee>();
                if(employee != null)
                {
                    var notification = new Notification();
                    notification.Employee.ID = employee.ID;
                    notification.Title = "HTTPS Certificate expires soon";
                    notification.Description = message;
                    DbFactory.FindStore<Notification>(employee.UserLink.ID, employee.UserLink.UserID, Platform.DatabaseEngine, "").Save(notification, "");
                }
                else
                {
                    Logger.Send(LogType.Information, "DATABASE", $"Certificate expiration subscriber {Properties.CertificateExpirationSubscriber} employee doesn't exist");
                }
            }
        }

        private void CertificateTimer_Elapsed(object? sender, ElapsedEventArgs e)
        {
            if (RestListener.Certificate != null)
            {
                X509Certificate2? cert = null;
                if (File.Exists(CertificateFileName()))
                {
                    cert = new X509Certificate2(CertificateFileName());
                }

                if(cert != null && cert.NotAfter > RestListener.Certificate.NotAfter && cert.NotAfter > DateTime.Now)
                {
                    Logger.Send(LogType.Information, "DATABASE", "HTTPS Certificate with greater expiry date found; restarting HTTPS listener...");
                    RestartListener();
                }

                var expiry = RestListener.Certificate.NotAfter;
                var untilExpiry = expiry - DateTime.Now;
                if(untilExpiry.TotalDays <= 7)
                {
                    SendCertificateExpiryNotification(expiry);
                    if (untilExpiry.TotalDays <= 1)
                    {
                        CertificateRefreshTimer?.Stop();

                        CertificateHaltTimer = new Timer(untilExpiry.TotalMilliseconds);
                        CertificateHaltTimer.Elapsed += HTTPS_Halt_Elapsed;
                        CertificateHaltTimer.AutoReset = false;
                        CertificateHaltTimer.Start();
                    }
                }
            }
        }

        /// <summary>
        /// Restarts listener in HTTP mode
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void HTTPS_Halt_Elapsed(object? sender, ElapsedEventArgs e)
        {
            CertificateHaltTimer?.Dispose();
            CertificateHaltTimer = null;

            Logger.Send(LogType.Information, "", "Expiry of certificate reached; restarting HTTPS listener...");
            RestartListener();
        }

        #endregion

        #region Desktop Installer Files

        private static bool CheckNewer(string filename)
        {
            var source = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "update", filename);
            var target = Path.Combine(CoreUtils.GetCommonAppData("PRSServer"), "update", filename);
            if (!File.Exists(target)) return true;
            if (!File.Exists(source)) return false;

            return File.GetLastWriteTimeUtc(source) > File.GetLastWriteTimeUtc(target);
        }
        private static void CopyFile(string filename)
        {
            var source = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "update", filename);
            var target = Path.Combine(CoreUtils.GetCommonAppData("PRSServer"), "update", filename);
            File.Copy(source, target, true);
        }
        public static void MoveUpdateFiles()
        {
            try
            {
                if (CheckNewer("version.txt") || CheckNewer("Release Notes.txt") || CheckNewer("PRSDesktopSetup.exe"))
                {
                    CopyFile("version.txt");
                    CopyFile("Release Notes.txt");
                    CopyFile("PRSDesktopSetup.exe");
                }
            }
            catch (Exception e)
            {
                Logger.Send(LogType.Error, "", $"Could not copy desktop update files: {e.Message}");
            }
        }

        #endregion

        private void RestartListener()
        {
            RestListener.Clear();
            RestListener.Init(Properties.WebSocketPort);
            InitialisePort();
            RestListener.Start();
        }

        public override void Stop()
        {
            Logger.Send(LogType.Information, "", "Stopping..");

            _socketserver?.Stop();
            _socketserver = null;
            
            _pipeserver?.Stop();
            _pipeserver = null;
            //PipeServer?.Dispose();

            RestListener.Stop();
            CredentialsCache.SaveSessionCache();
            
            CertificateRefreshTimer?.Stop();
            CertificateHaltTimer?.Stop();
        }
    }
}