using System;
using ln.http;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using ln.logging;
using ln.types;
using System.Net;
using ln.application.service;
using ln.http.resources;
using ln.types.btree;
using ln.types.rpc;
using ln.application.slots;
using ln.identities;
using ln.http.session;
using ln.json.mapping;
using ln.application.json;
using System.Reflection;

namespace ln.application
{
    public class Application : ResourceApplication
    {
        public String ApplicationName { get; protected set; } = "ln.application base";

        public ArgumentContainer Arguments { get; protected set; }
        public HTTPServer HttpServer { get; private set; }
        bool usesDedicatedHttpServer = false;

        public ServiceContainer ServiceContainer { get; }

        public MemoryLogger MemoryLogger { get; }

		public int ApplicationContextTimeout { get; set; } = 1200;

        public RPCContainer RPCContainer { get; } = new RPCContainer();
        public BinarySlotContainer BinarySlots { get; } = new BinarySlotContainer();

        public IIdentityProvider IdentityProvider { get; protected set; }

        MappingBTree<Guid, ApplicationSession> applicationSessions = new MappingBTree<Guid, ApplicationSession>((x)=>x.SessionID);

        public Application(HTTPServer httpServer, IIdentityProvider identityProvider,RPCContainer rpcContainer)
        {
            HttpServer = httpServer;

            IdentityProvider = identityProvider;
            RPCContainer = rpcContainer ?? new RPCContainer(CheckRPCAccess);

            MemoryLogger = new MemoryLogger(8192);
            Logger.Default.Backends.Add(MemoryLogger);

            Arguments = new ArgumentContainer()
                .Add((char)0, "log-level", "INFO")
                .Add('l', "http-listen", "0.0.0.0")
                .Add('p', "http-port", "8080");

            ServiceContainer = new ServiceContainer(this);

            RPCContainer.Add("",new ApplicationRPC(this));
            RPCContainer.Add("ServiceContainer", ServiceContainer.RPC);
        }


        public Application() :this(null,null,null) { }
        public Application(IIdentityProvider identityProvider) : this(null,identityProvider,null) { }

        bool CheckRPCAccess(RPCContainer container, RPCContainer.RPCModule module, System.Reflection.MethodInfo method)
        {
            RequireAttribute require = method.GetCustomAttribute<RequireAttribute>();
            if (require != null)
            {
                Identity currentIdentity = ApplicationSession.CurrentSession?.SessionIdentity;
                if (currentIdentity == null)
                    throw new AuthenticationNeeded();

                Guid requiredUID = require.IdentityUniqueID;
                if (require.IdentityName != null)
                {
                    requiredUID = currentIdentity.IdentityProvider.GetIdentity(require.IdentityName)?.UniqueID ?? throw new KeyNotFoundException();
                }

                return currentIdentity.AssignedRoles.HasRole(requiredUID, require.Role);
            }
            return true;
        }


        public virtual void PrepareStart()
        {
        }

        public void Start(String[] arguments)
        {
            Arguments.Parse(arguments);
            Logger.ConsoleLogger.MaxLogLevel = (LogLevel)Enum.Parse(typeof(LogLevel), Arguments["log-level"].Value);

            /* Startup Sequence */

            Logging.Log(LogLevel.INFO, "Calling PrepareStart()");
            PrepareStart();

            /* HTTP Server */
            if (HttpServer == null)
            {
                Logging.Log(LogLevel.INFO, "Start:    HTTPServer on {0}:{1}", Arguments['l'].Value, Arguments['p'].IntegerValue);
                HttpServer = new HTTPServer(new System.Net.IPEndPoint(
                                                IPAddress.Parse(Arguments['l'].Value),
                                                Arguments['p'].IntegerValue
                                            ),
                                            HttpRouter
                                        );
                HttpServer.Start();
                usesDedicatedHttpServer = true;
            }

            /* Application Services */

            foreach (ServiceDefinition serviceDefinition in ServiceContainer)
            {
                if (serviceDefinition.AutoStart && !serviceDefinition.IsAlive)
                    ServiceContainer.Start(serviceDefinition);
            }
        }
        public void Stop()
        {
            Logging.Log(LogLevel.INFO, "Application shutdown requested");

            /* Application Services */
            foreach (ServiceDefinition serviceDefinition in ServiceContainer)
            {
                if (serviceDefinition.IsAlive)
                {
                    ServiceContainer.Stop(serviceDefinition);
                    if (serviceDefinition.IsAlive)
                        throw new Exception("application service could not be stopped");
                }
            }

            /* HTTP Server */
            if (usesDedicatedHttpServer)
            {
                Logging.Log(LogLevel.INFO, "Stopping HTTP server");
                HttpServer.Stop();
            }
        }

		public virtual ApplicationSession CreateApplicationSession() => new ApplicationSession(this);
        public ApplicationSession GetApplicationSession(Session session)
        {
            ApplicationSession applicationSession = session.Get<ApplicationSession>("LNApplicationSession");
            if (applicationSession == null)
            {
                applicationSession = CreateApplicationSession();
                applicationSessions.Add(applicationSession);
                session["LNApplicationSession"] = applicationSession;
            }

            return applicationSession;
        }

        public ApplicationSession GetApplicationSession() => GetApplicationSession(Guid.Empty);
		public ApplicationSession GetApplicationSession(Guid contextID)
		{
			ApplicationSession applicationSession = null;

            if (!applicationSessions.TryGet(contextID,out applicationSession))
            { 
				while (true)
				{
					applicationSession = CreateApplicationSession();
					if (!applicationSessions.ContainsKey(applicationSession.SessionID))
					{
						applicationSessions.Add(applicationSession);
						break;
					}
				}
			}
			return applicationSession;
		}

        public virtual object ProcessMessage(object message)
        {
            //Application.BinarySlots.RequestSlot(message as SlotRequest);
            return null;
        }


        public virtual Identity Authenticate(string username,object prove)
		{
			return null;
		}

		public void CleanupApplicationContexts()
		{
			foreach (ApplicationSession applicationContext in applicationSessions.ToArray())
			{
				if (applicationContext.Untouched > TimeSpan.FromSeconds(ApplicationContextTimeout))
					applicationSessions.RemoveKey(applicationContext.SessionID);
			}
		}


		/*
         * Plugin Classes
         */
		Dictionary<Type, List<object>> pluginInstances = new Dictionary<Type, List<object>>();

        public void RegisterPluginInstance<PC>(PC pluginInstance) => RegisterPluginInstance(typeof(PC),pluginInstance);
        public void RegisterPluginInstance(Type type,object pluginInstance)
        {
            if (!pluginInstances.ContainsKey(type))
                pluginInstances.Add(type, new List<object>());

            if (!pluginInstances[type].Contains(pluginInstance))
                pluginInstances[type].Add(pluginInstance);
        }

        public IEnumerable<PC> GetPluginInstances<PC>()
        {
            Type pluginType = typeof(PC);
            if (!pluginInstances.ContainsKey(pluginType))
                return new PC[0];

            return pluginInstances[pluginType].Select((ut) => (PC)ut);
        }
        public IEnumerable GetPluginInstances(Type pluginType)
        {
            if (!pluginInstances.ContainsKey(pluginType))
                return new object[0];

            return pluginInstances[pluginType];
        }

        static Application()
        {
            JSONMapper.DefaultMapper.Add(new JSONIdentityMapping());
        }
    }
}