using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.SignalR;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
using xCommons.Extensions;
using xExceptions.Constants;
using xPushService.Configurations;
using xPushService.Constants;
using xPushService.Helpers;
using xPushService.Interfaces;
using xPushService.Providers;
using xPushService.Store;

namespace xPushService.DI {
    public static partial class XDIHelperExtension {
        /// <summary>
        /// Extract Module Configuration from provided IConfiguration
        /// </summary>
        /// <param name="config"></param>
        /// <returns>an instance of XPushServiceConfiguration</returns>
        public static XPushServiceConfiguration GetXPushServiceConfiguration (this IConfiguration config) {
            //
            var xPushConfigSection = config.GetSection (XPushServiceConstants.XConfigurationNodes.XPushServiceConfiguration);
            return xPushConfigSection.Get<XPushServiceConfiguration> ();
        }

        /// <summary>
        /// Register XPushServiceHelper ...
        /// </summary>
        /// <param name="services"></param>
        /// <param name="helper"></param>
        public static void AddXPushServiceHelper (
            this IServiceCollection services,
            XPushServiceHelper helper
        ) {
            //
            // Validate Args ...
            if (helper.IsNull ()) {
                //
                Log ("AddXPushServiceHelper failed, helper not provided ...");
                throw XException.InvalidArgs.ToException ();
            }

            //
            // Register Helper ...
            services.AddSingleton (helper);
        }

        /// <summary>
        /// Register Module Provided Service on DI
        /// </summary>
        /// <param name="services"></param>
        /// <param name="config"></param>
        public static void AddXPushService (
            this IServiceCollection services,
            IConfiguration config,
            ServiceLifetime lifeTime = ServiceLifetime.Singleton
        ) {
            AddPushService (
                services,
                config.GetXPushServiceConfiguration (),
                lifeTime
            );
        }

        /// <summary>
        /// Register Module Provided Service on DI
        /// </summary>
        /// <param name="services"></param>
        /// <param name="config"></param>
        public static void AddXPushService (
            this IServiceCollection services,
            XPushServiceConfiguration config,
            ServiceLifetime lifeTime = ServiceLifetime.Singleton
        ) {
            AddPushService (
                services,
                config,
                lifeTime
            );
        }

        /// <summary>
        /// Use Module Middlewares on Application Builder
        /// </summary>
        /// <param name="app"></param>
        /// <param name="helper"></param>
        public static void UseXPushService (
            this IApplicationBuilder app,
            XPushServiceHelper helper
        ) {
            //
            // Validate Args ...
            var isHelperExists = !helper.IsNull ();
            if (!isHelperExists) {
                //
                Log ("AddXPushServiceHelper failed, helper not provided ...");
                throw XException.InvalidArgs.ToException ();
            }

            //
            // Create an Scope for Accessing Registered Services ...
            using (var scope = app.ApplicationServices.CreateScope ()) {
                //
                // try to Retrieve Configuration ....
                var config = scope.ServiceProvider.GetService<XPushServiceConfiguration> ();
                if (
                    config.IsNull () ||
                    config.BaseRoute.IsNullOrEmpty () ||
                    config.BaseRoute.Trim ().IsNullOrEmpty ()
                ) {
                    //
                    Log ("AddXPushServiceHelper failed, Configuration not provided ...");
                    throw XException.InvalidConfiguration.ToException ();
                }

                //
                #region Normalize Routes ...
                //
                // Base Reoute ...
                config.BaseRoute = config.BaseRoute.ToNormalString ();
                if (!config.BaseRoute.StartsWith ("/")) {
                    config.BaseRoute = "/" + config.BaseRoute;
                }
                #endregion

                //
                // add XPushService Hub to Helper ...
                //
                var hubRoutes = new List<string> ();

                //
                // Try to Register Hubs ...
                //
                // Use SignalR in App ...
                app.UseSignalR (routes => {
                    //
                    helper.GetHubs ().ForEach (hubDescriptor => {
                        //
                        var hubRoute = Path.Combine (config.BaseRoute, hubDescriptor.Route);
                        hubRoutes.Add (hubRoute);
                        Console.WriteLine ($"XPushService HubRoute: {hubRoute}");

                        //
                        Type routesType = routes.GetType ();
                        MethodInfo mapHubMethod = routesType
                            .GetMethods ()
                            .SingleOrDefault (m =>
                                m.Name == "MapHub" &&
                                m.GetParameters ().Length == 1
                            );
                        if (mapHubMethod.IsNull ()) {
                            throw XException.ActionFailed.ToException ();
                        }

                        //
                        object[] genericMapHubMethodArgs = { new PathString (hubRoute) };
                        MethodInfo genericMapHubMethod = mapHubMethod.MakeGenericMethod (hubDescriptor.Hub);
                        genericMapHubMethod.Invoke (routes, genericMapHubMethodArgs);
                    });
                });
            }
        }

        //
        #region Private ...
        /// <summary>
        /// a LogTag for XPushService ...
        /// </summary>
        private static string XLogTag = "XPushService";

        /// <summary>
        /// print a log in Console ...
        /// </summary>
        /// <param name="message"></param>
        private static void Log (string message) {
            Console.WriteLine ($"{XLogTag} => {message}");
        }

        /// <summary>
        /// Register Push Service ...
        /// </summary>
        /// <param name="services"></param>
        /// <param name="config"></param>
        /// <param name="lifeTime"></param>
        private static void AddPushService (
            IServiceCollection services,
            XPushServiceConfiguration config,
            ServiceLifetime lifeTime
        ) {
            //
            #region Validate Args ...
            //
            var exception = XException.InvalidArgs.ToException ();;

            //
            // Services ...
            var isServicesExists = !services.IsNull ();
            if (!isServicesExists) {
                //
                Log ("AddXPushServiceHelper failed, services not provided ...");
                throw exception;
            }

            //
            // Config ...
            var isConfigExists = !config.IsNull ();
            if (!isConfigExists) {
                //
                Log ("AddXPushServiceHelper failed, configuration not provided ...");
                throw exception;
            }

            //
            // Lifetime ...
            var isLifetimeExists = !lifeTime.IsNull ();
            if (!isLifetimeExists) {
                //
                Log ("AddXPushServiceHelper failed, lifetime not provided ...");
                throw exception;
            }
            #endregion

            //
            // Register XPushService Configuration ...
            services.AddSingleton<XPushServiceConfiguration> (config);

            //
            #region Try to Register Stores ...
            //
            var groupStore = services.GetRegisteredService<IXPushGroupStore> ();
            if (groupStore.IsNull ()) {
                //
                Log ($"there is no provided PushGroupStore, try to register XPushGroupInMemoryStore ...");
                groupStore = new XPushGroupInMemoryStore ();
                services.AddSingleton<IXPushGroupStore> (groupStore);
            }

            //
            var connectionStore = services.GetRegisteredService<IXPushConnectionStore> ();
            if (connectionStore.IsNull ()) {
                //
                Log ($"there is no provided XPushConnectionStore, try to register XPushConnectionInMemoryStore ...");
                connectionStore = new XPushConnectionInMemoryStore ();
                services.AddSingleton<IXPushConnectionStore> (connectionStore);
            }

            //
            var webRtcConnectionStore = services.GetRegisteredService<IXWebRTCConnectionStore> ();
            if (webRtcConnectionStore.IsNull ()) {
                //
                Log ($"there is no provided XWebRTCConnectionStore, try to register XWebRTCConnectionInMemoryStore ...");
                webRtcConnectionStore = new XWebRTCConnectionInMemoryStore ();
                services.AddSingleton<IXWebRTCConnectionStore> (webRtcConnectionStore);
            }
            #endregion

            //
            // Register SignalR ...
            var builder = services.AddSignalR ();

            //
            // Add NewtonSoftJson Protocol ...
            builder.AddNewtonsoftJsonProtocol (x => {
                x.PayloadSerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
                x.PayloadSerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver ();
            });

            //
            // Register XPushServiceUserNameProvider ...
            services.AddSingleton<IUserIdProvider, XPushServiceUserNameProvider> ();

            //
            // add Message Protocol Support ...
            if (config.AddSupportMessageProtocol) {
                builder.AddMessagePackProtocol ();
            }
        }
        #endregion
    }
}