using Microsoft.WindowsAPICodePack.Net;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Net;
using System.Net.NetworkInformation;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Data;
using Tango.BL;
using Tango.Core;
using Tango.Core.Commands;
using Tango.Core.Cryptography;
using Tango.PPC.Common;
using Tango.PPC.Common.Application;
using Tango.PPC.Common.Build;
using Tango.PPC.Common.Connection;
using Tango.PPC.Common.Connectivity;
using Tango.PPC.Common.Notifications;
using Tango.Settings;
using Tango.WiFi;

namespace Tango.PPC.UI.Connectivity
{
    public class DefaultConnectivityProvider : ExtendedObject, IConnectivityProvider
    {
        private Wifi _wifi;
        private INotificationProvider _notification;
        private IMachineProvider _machineProvider;
        private Rfc2898Cryptographer _cryptographer;
        private System.Timers.Timer _updateTimer;
        private System.Timers.Timer _lanUpdateTimer;
        private WiFiNetwork _connectedNetwork;
        private PPCSettings _settings;
        private IBuildProvider _buildProvider;

        /// <summary>
        /// Occurs when the connectivity provider state has changed (e.g network connected/disconnected).
        /// </summary>
        public event EventHandler<ConnectionStateEventArgs> ConnectionStateChanged;

        private bool _isConnected;
        /// <summary>
        /// Gets a value indicating whether there is any Internet connection available.
        /// </summary>
        public bool IsConnected
        {
            get
            {
                return _buildProvider.IsEureka ? true : _isConnected;
            }
            private set { _isConnected = value; RaisePropertyChangedAuto(); }
        }

        private bool _isLanConnected;
        /// <summary>
        /// Gets a value indicating whether there is LAN connection.
        /// </summary>
        public bool IsLanConnected
        {
            get
            {
                return _buildProvider.IsEureka ? true : _isLanConnected;
            }
            private set { _isLanConnected = value; RaisePropertyChangedAuto(); }
        }

        private bool _isHotspoActive;
        /// <summary>
        /// Gets a value indicating whether the hot spot network is active.
        /// </summary>
        public bool IsHotspotActive
        {
            get { return _isHotspoActive; }
            set { _isHotspoActive = value; RaisePropertyChangedAuto(); }
        }

        /// <summary>
        /// Gets the available WiFi networks.
        /// </summary>
        public ObservableCollection<WiFiNetwork> AvailableWiFiNetworks { get; }

        /// <summary>
        /// Gets the available WiFi networks as a sorted view source by signal strength.
        /// </summary>
        public ICollectionView AvailableWiFiNetworksViewSource { get; set; }

        /// <summary>
        /// Gets the connect to WiFi command.
        /// </summary>
        public RelayCommand<WiFiNetwork> ConnectToWiFiCommand { get; private set; }

        /// <summary>
        /// Gets the disconnect from WiFi command.
        /// </summary>
        public RelayCommand<WiFiNetwork> DisconnectFromWiFiCommand { get; private set; }

        /// <summary>
        /// 
        /// </summary>
        public RelayCommand RefreshAvailableWiFiNetworksCommand { get; set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="DefaultConnectivityProvider"/> class.
        /// </summary>
        public DefaultConnectivityProvider(IPPCApplicationManager applicationManager, INotificationProvider notificationProvider, IMachineProvider machineProvider, IBuildProvider buildProvider)
        {
            _cryptographer = new Rfc2898Cryptographer();

            _buildProvider = buildProvider;
            _notification = notificationProvider;
            _machineProvider = machineProvider;

            AvailableWiFiNetworks = new ObservableCollection<WiFiNetwork>();
            AvailableWiFiNetworks.EnableCrossThreadOperations();
            AvailableWiFiNetworksViewSource = CollectionViewSource.GetDefaultView(AvailableWiFiNetworks);

            AvailableWiFiNetworksViewSource.SortDescriptions.Add(new SortDescription(nameof(WiFiNetwork.IsConnected), ListSortDirection.Descending));
            AvailableWiFiNetworksViewSource.SortDescriptions.Add(new SortDescription(nameof(WiFiNetwork.SignalStrength), ListSortDirection.Descending));

            if (!_buildProvider.IsEureka)
            {
                _wifi = new Wifi();
                applicationManager.ApplicationReady += ApplicationManager_Ready;
            }

            ConnectToWiFiCommand = new RelayCommand<WiFiNetwork>(async (x) =>
            {
                await Connect(x);
            });

            DisconnectFromWiFiCommand = new RelayCommand<WiFiNetwork>((x) =>
            {
                Disconnect(x);
            });

            RefreshAvailableWiFiNetworksCommand = new RelayCommand(async () =>
            {
                await RefreshAvailableWiFiNetworks();
            });

            _settings = SettingsManager.Default.GetOrCreate<PPCSettings>();
        }

        /// <summary>
        /// Handles the application manager ApplicationReady event.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ApplicationManager_Ready(object sender, EventArgs e)
        {
            Task.Factory.StartNew(async () =>
            {
                Thread.Sleep(2000);

                await RefreshAvailableWiFiNetworks();
                var settings = SettingsManager.Default.GetOrCreate<PPCSettings>();

                var networks = AvailableWiFiNetworks.ToList();

                var auto_connect_network = networks.FirstOrDefault(x => x.Name == settings.AutoConnectWiFiName);

                IsConnected = networks.Exists(x => x.IsConnected);

                if (IsConnected)
                {
                    _connectedNetwork = auto_connect_network;
                }

                if (auto_connect_network != null && !auto_connect_network.IsConnected)
                {
                    auto_connect_network.AutoConnect = true;
                    await Connect(auto_connect_network, _cryptographer.Decrypt(settings.AutoConnectWiFiPassword));
                }
            });

            _updateTimer = new System.Timers.Timer(TimeSpan.FromSeconds(30).TotalMilliseconds);
            _updateTimer.Elapsed += _updateTimer_Elapsed;
            _updateTimer.Start();

            _lanUpdateTimer = new System.Timers.Timer(TimeSpan.FromSeconds(10).TotalMilliseconds);
            _lanUpdateTimer.Elapsed += _lanUpdateTimer_Elapsed;
            _lanUpdateTimer.Start();
        }

        private void _lanUpdateTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            foreach (NetworkInterface net in NetworkInterface.GetAllNetworkInterfaces())
            {
                if ((net.NetworkInterfaceType == NetworkInterfaceType.Ethernet
                    || net.NetworkInterfaceType == NetworkInterfaceType.Ethernet3Megabit
                    || net.NetworkInterfaceType == NetworkInterfaceType.FastEthernetFx
                    || net.NetworkInterfaceType == NetworkInterfaceType.FastEthernetT
                    || net.NetworkInterfaceType == NetworkInterfaceType.GigabitEthernet) && net.Name.ToStringOrEmpty().StartsWith("Ethernet") && net.OperationalStatus == OperationalStatus.Up)
                {
                    IsLanConnected = true;
                    return;
                }
            }

            IsLanConnected = false;
        }

        /// <summary>
        /// Periodically checks if WiFI network is gone/disconnected.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="System.Timers.ElapsedEventArgs"/> instance containing the event data.</param>
        private void _updateTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            if (IsConnected && _connectedNetwork != null)
            {
                var networks = GetAvailableWiFiNetworks().Result;
                var matching_network = networks.FirstOrDefault(x => x.Name == _connectedNetwork.Name);

                if (matching_network == null || !matching_network.AccessPoint.IsConnected)
                {
                    OnConnectionStateChanged(false);
                }
            }
        }

        /// <summary>
        /// Gets the available WiFi networks.
        /// </summary>
        /// <returns></returns>
        public Task<List<WiFiNetwork>> GetAvailableWiFiNetworks()
        {
            return Task.Factory.StartNew<List<WiFiNetwork>>(() =>
            {
                var accessPoints = _wifi.GetAccessPoints();

                AvailableWiFiNetworks.Where(x => !accessPoints.ToList().Exists(y => y.Name == x.Name)).ToList().ForEach(x => AvailableWiFiNetworks.Remove(x));

                foreach (var ap in accessPoints.ToList())
                {
                    var network = AvailableWiFiNetworks.FirstOrDefault(x => x.Name == ap.Name);

                    if (network == null)
                    {
                        network = new WiFiNetwork(ap, _wifi);
                        AvailableWiFiNetworks.Add(network);
                    }
                    else
                    {
                        network.AccessPoint = ap;
                    }
                }

                return AvailableWiFiNetworks.ToList();
            });
        }

        /// <summary>
        /// Resets the available WiFi networks collection.
        /// </summary>
        public Task RefreshAvailableWiFiNetworks()
        {
            return Task.Factory.StartNew(() =>
            {
                AvailableWiFiNetworks.Clear();

                if (!_buildProvider.IsEureka)
                {
                    GetAvailableWiFiNetworks().Wait();
                }
            });
        }

        /// <summary>
        /// Checks the Internet connection.
        /// </summary>
        /// <returns></returns>
        public Task<bool> CheckInternetConnection()
        {
            if (_settings.BypassInternetConnectivityCheck)
            {
                return Task.FromResult(true);
            }

            return Task.Factory.StartNew<bool>(() =>
            {
                try
                {
                    return NetworkListManager.GetNetworks(NetworkConnectivityLevels.Connected).Any(x => x.IsConnectedToInternet);
                }
                catch
                {
                    return true;
                }
            });
        }

        /// <summary>
        /// Connects the specified network.
        /// </summary>
        /// <param name="network">The network.</param>
        /// <returns></returns>
        public async Task<bool> Connect(WiFiNetwork network, String password = null)
        {
            var auth = network.CreateAuthenticationRequest();

            bool result = false;

            if (password == null)
            {
                if ((auth.IsPasswordRequired || auth.IsUserNameRequired) && !network.HasProfile)
                {
                    var vm = await _notification.ShowDialog<WiFiAuthenticationViewVM>(new WiFiAuthenticationViewVM(auth, network));

                    if (vm.DialogResult)
                    {
                        result = await network.Connect(auth, true);

                        if (!result)
                        {
                            await _notification.ShowError("Could not connect to the specified network. Please check your password.");
                            await network.Forget();
                        }

                        await RefreshAvailableWiFiNetworks();
                    }
                    else
                    {
                        return false;
                    }
                }
                else
                {
                    result = await network.Connect(auth, false);
                    await RefreshAvailableWiFiNetworks();
                }
            }
            else
            {
                auth.Password = password;
                result = await network.Connect(auth, true);
                await RefreshAvailableWiFiNetworks();
            }

            if (result)
            {
                OnConnectionStateChanged(true);
                var settings = SettingsManager.Default.GetOrCreate<PPCSettings>();
                settings.AutoConnectWiFiName = network.AutoConnect ? network.Name : null;
                settings.AutoConnectWiFiPassword = _cryptographer.Encrypt(auth.Password);
                settings.Save();
                _connectedNetwork = network;
            }

            return result;
        }

        /// <summary>
        /// Disconnects the specified network.
        /// </summary>
        /// <param name="network">The network.</param>
        /// <returns></returns>
        public void Disconnect(WiFiNetwork network)
        {
            Task.Factory.StartNew(() =>
            {
                var settings = SettingsManager.Default.GetOrCreate<PPCSettings>();
                settings.AutoConnectWiFiName = null;
                settings.AutoConnectWiFiPassword = null;
                settings.Save();
                network.AutoConnect = false;
                network.Disconnect().Wait();
                RefreshAvailableWiFiNetworks().Wait();
                OnConnectionStateChanged(false);
            });
        }

        /// <summary>
        /// Called when the connection state has been changed
        /// </summary>
        /// <param name="connected">if set to <c>true</c> [connected].</param>
        protected virtual void OnConnectionStateChanged(bool connected)
        {
            if (!connected)
            {
                _connectedNetwork = null;
            }
            IsConnected = connected;
            ConnectionStateChanged?.Invoke(this, new ConnectionStateEventArgs() { IsConnected = connected });
        }
    }
}