using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.IO;
using System.Threading.Tasks;

using SharedLibraryCore;
using SharedLibraryCore.Interfaces;
using SharedLibraryCore.Commands;
using SharedLibraryCore.Helpers;
using SharedLibraryCore.Exceptions;
using SharedLibraryCore.Objects;
using SharedLibraryCore.Services;
using IW4MAdmin.Application.API;
using Microsoft.Extensions.Configuration;
using WebfrontCore;
using SharedLibraryCore.Configuration;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Text;
using IW4MAdmin.Application.API.Master;
using System.Reflection;

namespace IW4MAdmin.Application
{
    public class ApplicationManager : IManager
    {
        private List<Server> _servers;
        public List<Server> Servers => _servers.OrderByDescending(s => s.ClientNum).ToList();
        public Dictionary<int, Player> PrivilegedClients { get; set; }
        public ILogger Logger { get; private set; }
        public bool Running { get; private set; }
        public EventHandler<GameEvent> ServerEventOccurred { get; private set; }
        public DateTime StartTime { get; private set; }

        static ApplicationManager Instance;
        List<AsyncStatus> TaskStatuses;
        List<Command> Commands;
        List<MessageToken> MessageTokens;
        ClientService ClientSvc;
        AliasService AliasSvc;
        PenaltyService PenaltySvc;
        BaseConfigurationHandler<ApplicationConfiguration> ConfigHandler;
        EventApi Api;
        GameEventHandler Handler;
        ManualResetEventSlim OnEvent;

        private ApplicationManager()
        {
            Logger = new Logger($@"{Utilities.OperatingDirectory}IW4MAdmin.log");
            _servers = new List<Server>();
            Commands = new List<Command>();
            TaskStatuses = new List<AsyncStatus>();
            MessageTokens = new List<MessageToken>();
            ClientSvc = new ClientService();
            AliasSvc = new AliasService();
            PenaltySvc = new PenaltyService();
            PrivilegedClients = new Dictionary<int, Player>();
            Api = new EventApi();
            ServerEventOccurred += Api.OnServerEvent;
            ConfigHandler = new BaseConfigurationHandler<ApplicationConfiguration>("IW4MAdminSettings");
            StartTime = DateTime.UtcNow;
            OnEvent = new ManualResetEventSlim();
        }

        public IList<Server> GetServers()
        {
            return Servers;
        }

        public IList<Command> GetCommands()
        {
            return Commands;
        }

        public static ApplicationManager GetInstance()
        {
            return Instance ?? (Instance = new ApplicationManager());
        }

        public async Task UpdateStatus(object state)
        {
            var taskList = new List<Task>();

            while (Running)
            {
                taskList.Clear();
                foreach (var server in Servers)
                {
                    taskList.Add(Task.Run(async () =>
                    {
                        try
                        {
                            await server.ProcessUpdatesAsync(new CancellationToken());
                        }

                        catch (Exception e)
                        {
                            Logger.WriteWarning($"Failed to update status for {server}");
                            Logger.WriteDebug($"Exception: {e.Message}");
                            Logger.WriteDebug($"StackTrace: {e.StackTrace}");
                        }
                    }));
                }
#if DEBUG
                Logger.WriteDebug($"{taskList.Count} servers queued for stats updates");
                ThreadPool.GetMaxThreads(out int workerThreads, out int n);
                ThreadPool.GetAvailableThreads(out int availableThreads, out int m);
                Logger.WriteDebug($"There are {workerThreads - availableThreads} active threading tasks");
#endif

                await Task.WhenAny(taskList);
                await Task.Delay(ConfigHandler.Configuration().RConPollRate);
            }
        }

        public async Task Init()
        {
            Running = true;

            #region DATABASE
            var ipList = (await ClientSvc.Find(c => c.Level > Player.Permission.Trusted))
                .Select(c => new
                {
                    c.Password,
                    c.PasswordSalt,
                    c.ClientId,
                    c.Level,
                    c.Name
                });

            foreach (var a in ipList)
            {
                try
                {
                    PrivilegedClients.Add(a.ClientId, new Player()
                    {
                        Name = a.Name,
                        ClientId = a.ClientId,
                        Level = a.Level,
                        PasswordSalt = a.PasswordSalt,
                        Password = a.Password
                    });
                }

                catch (ArgumentException)
                {
                    continue;
                }
            }
            #endregion

            #region CONFIG
            var config = ConfigHandler.Configuration();

            // copy over default config if it doesn't exist
            if (config == null)
            {
                var defaultConfig = new BaseConfigurationHandler<DefaultConfiguration>("DefaultSettings").Configuration();
                ConfigHandler.Set((ApplicationConfiguration)new ApplicationConfiguration().Generate());
                var newConfig = ConfigHandler.Configuration();

                newConfig.AutoMessagePeriod = defaultConfig.AutoMessagePeriod;
                newConfig.AutoMessages = defaultConfig.AutoMessages;
                newConfig.GlobalRules = defaultConfig.GlobalRules;
                newConfig.Maps = defaultConfig.Maps;

                if (newConfig.Servers == null)
                {
                    ConfigHandler.Set(newConfig);
                    newConfig.Servers = new List<ServerConfiguration>();

                    do
                    {
                        newConfig.Servers.Add((ServerConfiguration)new ServerConfiguration().Generate());
                    } while (Utilities.PromptBool(Utilities.CurrentLocalization.LocalizationIndex["SETUP_SERVER_SAVE"]));

                    config = newConfig;
                    await ConfigHandler.Save();
                }
            }

            else if (config != null)
            {
                if (string.IsNullOrEmpty(config.Id))
                {
                    config.Id = Guid.NewGuid().ToString();
                    await ConfigHandler.Save();
                }

                if (string.IsNullOrEmpty(config.WebfrontBindUrl))
                {
                    config.WebfrontBindUrl = "http://127.0.0.1:1624";
                    await ConfigHandler.Save();
                }
            }

            else if (config.Servers.Count == 0)
                throw new ServerException("A server configuration in IW4MAdminSettings.json is invalid");

            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
            Utilities.EncodingType = Encoding.GetEncoding(!string.IsNullOrEmpty(config.CustomParserEncoding) ? config.CustomParserEncoding : "windows-1252");

            #endregion
            #region PLUGINS
            SharedLibraryCore.Plugins.PluginImporter.Load(this);

            foreach (var Plugin in SharedLibraryCore.Plugins.PluginImporter.ActivePlugins)
            {
                try
                {
                    await Plugin.OnLoadAsync(this);
                }

                catch (Exception e)
                {
                    Logger.WriteError($"{Utilities.CurrentLocalization.LocalizationIndex["SERVER_ERROR_PLUGIN"]} {Plugin.Name}");
                    Logger.WriteDebug($"Exception: {e.Message}");
                    Logger.WriteDebug($"Stack Trace: {e.StackTrace}");
                }
            }
            #endregion

            #region COMMANDS
            if (ClientSvc.GetOwners().Result.Count == 0)
                Commands.Add(new COwner());

            Commands.Add(new CQuit());
            Commands.Add(new CKick());
            Commands.Add(new CSay());
            Commands.Add(new CTempBan());
            Commands.Add(new CBan());
            Commands.Add(new CWhoAmI());
            Commands.Add(new CList());
            Commands.Add(new CHelp());
            Commands.Add(new CFastRestart());
            Commands.Add(new CMapRotate());
            Commands.Add(new CSetLevel());
            Commands.Add(new CUsage());
            Commands.Add(new CUptime());
            Commands.Add(new CWarn());
            Commands.Add(new CWarnClear());
            Commands.Add(new CUnban());
            Commands.Add(new CListAdmins());
            Commands.Add(new CLoadMap());
            Commands.Add(new CFindPlayer());
            Commands.Add(new CListRules());
            Commands.Add(new CPrivateMessage());
            Commands.Add(new CFlag());
            Commands.Add(new CUnflag());
            Commands.Add(new CReport());
            Commands.Add(new CListReports());
            Commands.Add(new CListBanInfo());
            Commands.Add(new CListAlias());
            Commands.Add(new CExecuteRCON());
            Commands.Add(new CPlugins());
            Commands.Add(new CIP());
            Commands.Add(new CMask());
            Commands.Add(new CPruneAdmins());
            Commands.Add(new CKillServer());
            Commands.Add(new CSetPassword());
            Commands.Add(new CPing());
            Commands.Add(new CSetGravatar());
            Commands.Add(new CNextMap());

            foreach (Command C in SharedLibraryCore.Plugins.PluginImporter.ActiveCommands)
                Commands.Add(C);
            #endregion

            #region INIT
            async Task Init(ServerConfiguration Conf)
            {
                // setup the event handler after the class is initialized
                Handler = new GameEventHandler(this);
                try
                {
                    var ServerInstance = new IW4MServer(this, Conf);
                    await ServerInstance.Initialize();

                    lock (_servers)
                    {
                        _servers.Add(ServerInstance);
                    }

                    Logger.WriteVerbose($"{Utilities.CurrentLocalization.LocalizationIndex["MANAGER_MONITORING_TEXT"]} {ServerInstance.Hostname}");
                    // add the start event for this server
                    Handler.AddEvent(new GameEvent(GameEvent.EventType.Start, "Server started", null, null, ServerInstance));
                }

                catch (ServerException e)
                {
                    Logger.WriteError($"{Utilities.CurrentLocalization.LocalizationIndex["SERVER_ERROR_UNFIXABLE"]} [{Conf.IPAddress}:{Conf.Port}]");
                    if (e.GetType() == typeof(DvarException))
                        Logger.WriteDebug($"{Utilities.CurrentLocalization.LocalizationIndex["SERVER_ERROR_DVAR"]} {(e as DvarException).Data["dvar_name"]} ({Utilities.CurrentLocalization.LocalizationIndex["SERVER_ERROR_DVAR_HELP"]})");
                    else if (e.GetType() == typeof(NetworkException))
                    {
                        Logger.WriteDebug(e.Message);
                    }

                    // throw the exception to the main method to stop before instantly exiting
                    throw e;
                }
            }

            await Task.WhenAll(config.Servers.Select(c => Init(c)).ToArray());
            #endregion
        }

        private async Task SendHeartbeat(object state)
        {
            var heartbeatState = (HeartbeatState)state;

            while (Running)
            {
                if (!heartbeatState.Connected)
                {
                    try
                    {
                        await Heartbeat.Send(this, true);
                        heartbeatState.Connected = true;
                    }

                    catch (Exception e)
                    {
                        heartbeatState.Connected = false;
                        Logger.WriteWarning($"Could not connect to heartbeat server - {e.Message}");
                    }
                }

                else
                {
                    try
                    {
                        await Heartbeat.Send(this);
                    }

                    catch (System.Net.Http.HttpRequestException e)
                    {
                        Logger.WriteWarning($"Could not send heartbeat - {e.Message}");
                    }

                    catch (AggregateException e)
                    {
                        Logger.WriteWarning($"Could not send heartbeat - {e.Message}");
                        var exceptions = e.InnerExceptions.Where(ex => ex.GetType() == typeof(RestEase.ApiException));

                        foreach (var ex in exceptions)
                        {
                            if (((RestEase.ApiException)ex).StatusCode == System.Net.HttpStatusCode.Unauthorized)
                            {
                                heartbeatState.Connected = false;
                            }
                        }
                    }

                    catch (RestEase.ApiException e)
                    {
                        Logger.WriteWarning($"Could not send heartbeat - {e.Message}");
                        if (e.StatusCode == System.Net.HttpStatusCode.Unauthorized)
                        {
                            heartbeatState.Connected = false;
                        }
                    }
                    catch (Exception e)
                    {
                        Logger.WriteWarning($"Could not send heartbeat - {e.Message}");
                    }

                }
                await Task.Delay(30000);
            }
        }

        public async Task Start()
        {
            // this needs to be run seperately from the main thread
#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
#if !DEBUG
            // start heartbeat
            Task.Run(() => SendHeartbeat(new HeartbeatState()));
#endif
            Task.Run(() => UpdateStatus(null));
#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed

            var eventList = new List<Task>();

            async Task processEvent(GameEvent newEvent)
            {
                try
                {
                    await newEvent.Owner.ExecuteEvent(newEvent);
#if DEBUG
                    Logger.WriteDebug("Processed Event");
#endif
                }

                // this happens if a plugin requires login
                catch (AuthorizationException e)
                {
                    await newEvent.Origin.Tell($"{Utilities.CurrentLocalization.LocalizationIndex["COMMAND_NOTAUTHORIZED"]} - {e.Message}");
                }

                catch (NetworkException e)
                {
                    Logger.WriteError(Utilities.CurrentLocalization.LocalizationIndex["SERVER_ERROR_COMMUNICATION"]);
                    Logger.WriteDebug(e.Message);
                }

                catch (Exception E)
                {
                    Logger.WriteError($"{Utilities.CurrentLocalization.LocalizationIndex["SERVER_ERROR_EXCEPTION"]} {newEvent.Owner}");
                    Logger.WriteDebug("Error Message: " + E.Message);
                    Logger.WriteDebug("Error Trace: " + E.StackTrace);
                }
                // tell anyone waiting for the output that we're done
                newEvent.OnProcessed.Set();
            };

            GameEvent queuedEvent = null;

            while (Running)
            {
                // wait for new event to be added
                OnEvent.Wait();
                var taskList = new List<Task>();
                // todo: sequencially or parallelize?
                while ((queuedEvent = Handler.GetNextEvent()) != null)
                {
                    if (queuedEvent.Origin != null &&
                        !queuedEvent.Origin.IsAuthenticated &&
                        // we want to allow join events
                        queuedEvent.Type != GameEvent.EventType.Join &&
                        queuedEvent.Type != GameEvent.EventType.Quit &&
                        // we don't care about unknown events
                        queuedEvent.Origin.NetworkId != 0)
                    {
                        Logger.WriteDebug($"Delaying execution of event type {queuedEvent.Type} for {queuedEvent.Origin} because they are not authed");
                        // update the event origin for possible authed client
                        queuedEvent.Origin = queuedEvent.Owner.Players.FirstOrDefault(p => p != null && p.NetworkId == queuedEvent.Origin.NetworkId);
                        queuedEvent.Target = queuedEvent.Target == null ? null : queuedEvent.Owner.Players.FirstOrDefault(p => p != null && p.NetworkId == queuedEvent.Target.NetworkId);
                        // add it back to the queue for reprocessing
                        Handler.AddEvent(queuedEvent, true);
                        continue;
                    }
                    await processEvent(queuedEvent);
                }

                if (taskList.Count > 0)
                {
                    // this should allow parallel processing of events
                    await Task.WhenAny(taskList);
                }

                // signal that all events have been processed
                OnEvent.Reset();
            }
#if !DEBUG
            foreach (var S in _servers)
                await S.Broadcast("^1" + Utilities.CurrentLocalization.LocalizationIndex["BROADCAST_OFFLINE"]);
#endif
            _servers.Clear();
        }


        public void Stop()
        {
            Running = false;

            // trigger the event processing loop to end
            SetHasEvent();
        }

        public ILogger GetLogger()
        {
            return Logger;
        }

        public IList<MessageToken> GetMessageTokens()
        {
            return MessageTokens;
        }

        public IList<Player> GetActiveClients()
        {
            var ActiveClients = new List<Player>();

            foreach (var server in _servers)
                ActiveClients.AddRange(server.Players.Where(p => p != null));

            return ActiveClients;
        }

        public ClientService GetClientService() => ClientSvc;
        public AliasService GetAliasService() => AliasSvc;
        public PenaltyService GetPenaltyService() => PenaltySvc;
        public IConfigurationHandler<ApplicationConfiguration> GetApplicationSettings() => ConfigHandler;
        public IDictionary<int, Player> GetPrivilegedClients() => PrivilegedClients;
        public IEventApi GetEventApi() => Api;
        public bool ShutdownRequested() => !Running;
        public IEventHandler GetEventHandler() => Handler;

        public void SetHasEvent()
        {
            OnEvent.Set();
        }

        public IList<Assembly> GetPluginAssemblies() => SharedLibraryCore.Plugins.PluginImporter.PluginAssemblies;
    }
}