using System;
using System.Collections.Generic;
using System.Linq;
using System.Reactive.Concurrency;
using System.Reactive.Linq;
using System.Security.Authentication;
using System.Text;
using System.Threading.Tasks;
using Tango.BL;
using Tango.BL.Entities;
using Tango.Integration.Operation;
using Tango.Logging;
using Tango.PMR;
using Tango.PMR.Common;
using Tango.PMR.Connection;
using Tango.PMR.Integration;
using Tango.Settings;
using Tango.Transport;
using Tango.Transport.Adapters;
using Tango.Transport.Transporters;

namespace Tango.Integration.ExternalBridge
{
    /// <summary>
    /// Represents a secure external bridge TCP client.
    /// </summary>
    /// <seealso cref="Tango.Transport.Transporters.BasicTransporter" />
    /// <seealso cref="Tango.Integration.ExternalBridge.IExternalBridgeSecureClient" />
    public class ExternalBridgeTcpClient : MachineOperator, IExternalBridgeSecureClient
    {
        private bool _logs_sent;

        #region Properties

        private String _serialNumber;
        /// <summary>
        /// Gets the machine serial number.
        /// </summary>
        public String SerialNumber
        {
            get { return _serialNumber; }
            set
            {
                _serialNumber = value;
                RaisePropertyChangedAuto();
            }
        }

        private String _ipAddress;
        /// <summary>
        /// Gets or sets the machine IP address.
        /// </summary>
        public String IPAddress
        {
            get { return _ipAddress; }
            set { _ipAddress = value; RaisePropertyChangedAuto(); }
        }

        private bool _enableApplicationLogs;
        /// <summary>
        /// Gets or sets a value indicating whether to enable receiving application logs.
        /// </summary>
        public bool EnableApplicationLogs
        {
            get { return _enableApplicationLogs; }
            set
            {
                _enableApplicationLogs = value;
                RaisePropertyChangedAuto();
                OnEnableApplicationLogsChanged(value);
            }
        }

        /// <summary>
        /// Gets a value indicating whether this client requires authentication.
        /// </summary>
        public bool RequiresAuthentication => true;

        #endregion

        public override Task Connect()
        {
            throw new NotImplementedException("External Bridge TCP client must connect through the dedicated connect method.");
        }

        /// <summary>
        /// Connects to a remote external bridge service using the specified login.
        /// </summary>
        /// <param name="login">The login.</param>
        /// <returns></returns>
        /// <exception cref="AuthenticationException">The machine password is invalid.</exception>
        public async Task Connect(ExternalBridgeLoginRequest login)
        {
            if (State != TransportComponentState.Connected)
            {
                try
                {
                    Adapter = new TcpTransportAdapter(IPAddress, SettingsManager.Default.GetOrCreate<IntegrationSettings>().ExternalBridgeServicePort);
                    await Adapter.Connect();

                    State = TransportComponentState.Connected;
                    StartThreads();

                    LogManager.Log("External Bridge TCP Client Connected...");


                    LogRequestSent(login);

                    var response = await SendRequest<ExternalBridgeLoginRequest, ExternalBridgeLoginResponse>(login);
                    DeviceInformation = response.Message.DeviceInformation;
                    if (!response.Message.Authenticated)
                    {
                        await Adapter.Disconnect();
                        throw new AuthenticationException(response.Container.ErrorMessage);
                    }

                    Status = MachineStatuses.ReadyToDye;
                }
                catch (Exception ex)
                {
                    LogRequestFailed(login, ex);
                    try
                    {
                        await Adapter.Disconnect();
                    }
                    catch { }

                    throw ex;
                }

                OnEnableDiagnosticsChanged(EnableDiagnostics);
                OnEnableEmbeddedDebuggingChanged(EnableEmbeddedDebugging);
                OnEnableEventsNotification(EnableEventsNotification);
                OnEnableApplicationLogsChanged(EnableApplicationLogs);
                OnEnableMachineStatusUpdatesChanged(EnableMachineStatusUpdates);
            }
        }

        private async void OnEnableApplicationLogsChanged(bool value)
        {
            if (value && State == TransportComponentState.Connected && !_logs_sent)
            {
                var request = new StartApplicationLogsRequest();

                bool responseLogged = false;
                _logs_sent = true;

                SendContinuousRequest<StartApplicationLogsRequest, StartApplicationLogsResponse>(request).ObserveOn(new NewThreadScheduler())
                    .Subscribe
                    (
                    (response) =>
                    {
                        if (!responseLogged)
                        {
                            LogResponseReceived(response.Message);
                            responseLogged = true;
                        }

                        OnApplicationLogAvailable(response);
                    },
                    (ex) =>
                    {
                        _logs_sent = false;

                        if (!(ex is ContinuousResponseAbortedException))
                        {
                            LogRequestFailed(request, ex);
                        }
                    },
                    () =>
                    {
                        _logs_sent = false;
                    });

                LogRequestSent(request);
            }
            else if (_logs_sent)
            {
                _logs_sent = false;

                if (State == TransportComponentState.Connected)
                {
                    var req = new StopApplicationLogsRequest();

                    try
                    {
                        LogRequestSent(req);
                        var res = await SendRequest<StopApplicationLogsRequest, StopApplicationLogsResponse>(req);
                        LogResponseReceived(res.Message);
                    }
                    catch (Exception ex)
                    {
                        LogRequestFailed(req, ex);
                    }
                }
            }
        }

        private void OnApplicationLogAvailable(TangoMessage<StartApplicationLogsResponse> response)
        {
            try
            {
                if (response.Message.LogItem.Count() > 0)
                {
                    LogItemBase log = LogItemBase.Deserialize(response.Message.LogItem.ToArray());
                    log.LogObject = "External Bridge";
                    LogManager.Log(log);
                }
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error deserializing incoming application log item!");
            }
        }

        public async override Task Disconnect()
        {
            if (State == TransportComponentState.Connected)
            {
                ExternalBridgeLogoutRequest request = new ExternalBridgeLogoutRequest();
                LogRequestSent(request);

                try
                {
                    var response = await SendRequest<ExternalBridgeLogoutRequest, ExternalBridgeLogoutResponse>(request);
                    LogResponseReceived(response.Message);

                    Status = MachineStatuses.Standby;
                }
                catch (Exception ex)
                {
                    LogRequestFailed(request, ex);
                }
            }

            State = TransportComponentState.Disconnected;
            if (Adapter != null)
            {
                await Adapter.Disconnect();
            }
            LogManager.Log("External Bridge TCP client disconnected.");
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="ExternalBridgeTcpClient"/> class.
        /// </summary>
        /// <param name="serialNumber">The machine serial number.</param>
        /// <param name="ipAddress">The machine IP address.</param>
        public ExternalBridgeTcpClient(String serialNumber, String ipAddress)
        {
            SerialNumber = serialNumber;
            Machine = ObservablesStaticCollections.Instance.Machines.SingleOrDefault(x => x.SerialNumber == serialNumber);
            IPAddress = ipAddress;
            KeepAliveTimeout = TimeSpan.FromSeconds(5);
            KeepAliveRetries = 2;
            UseKeepAlive = false;
            EnableDiagnostics = true;
        }

        /// <summary>
        /// Returns a <see cref="System.String" /> that represents this instance.
        /// </summary>
        /// <returns>
        /// A <see cref="System.String" /> that represents this instance.
        /// </returns>
        public override string ToString()
        {
            return SerialNumber;
        }

        /// <summary>
        /// Called when a new request has been received.
        /// </summary>
        /// <param name="request">The request.</param>
        protected async override void OnRequestReceived(MessageContainer request)
        {
            base.OnRequestReceived(request);

            if (request.Type == MessageType.ExternalBridgeLogoutRequest)
            {
                await SendResponse<ExternalBridgeLogoutResponse>(new ExternalBridgeLogoutResponse(), request.Token);
                try
                {
                    State = TransportComponentState.Disconnected;
                    if (Adapter != null)
                    {
                        await Adapter.Disconnect();
                    }
                    LogManager.Log("External Bridge TCP client disconnected by the remote host.");
                }
                catch { }
                SessionClosed?.Invoke(this, new EventArgs());
            }
        }

        /// <summary>
        /// Occurs when the remote host has closed the session.
        /// </summary>
        public event EventHandler SessionClosed;

        /// <summary>
        /// Gets the database machine associated with this client.
        /// </summary>
        public Machine Machine { get; private set; }

        /// <summary>
        /// Sets the database machine.
        /// </summary>
        /// <param name="machine">The machine.</param>
        public void SetMachine(Machine machine)
        {
            Machine = machine;
        }
    }
}