namespace Microsoft.eShopOnContainers.Services.Marketing.API
{
    using AspNetCore.Builder;
    using AspNetCore.Hosting;
    using AspNetCore.Http;
    using Autofac;
    using Autofac.Extensions.DependencyInjection;
    using Azure.ServiceBus;
    using BuildingBlocks.EventBus;
    using BuildingBlocks.EventBus.Abstractions;
    using BuildingBlocks.EventBusRabbitMQ;
    using BuildingBlocks.EventBusServiceBus;
    using EntityFrameworkCore;
    using Extensions.Configuration;
    using Extensions.DependencyInjection;
    using Extensions.HealthChecks;
    using Extensions.Logging;
    using Infrastructure;
    using Infrastructure.Filters;
    using Infrastructure.Repositories;
    using Infrastructure.Services;
    using IntegrationEvents.Events;
    using Marketing.API.IntegrationEvents.Handlers;
    using Microsoft.AspNetCore.Authentication.JwtBearer;
    using Microsoft.EntityFrameworkCore.Diagnostics;
    using RabbitMQ.Client;
    using Swashbuckle.AspNetCore.Swagger;
    using System;
    using System.Collections.Generic;
    using System.IdentityModel.Tokens.Jwt;
    using System.Reflection;
    using System.Threading.Tasks;

    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }


        // This method gets called by the runtime. Use this method to add services to the container.
        public IServiceProvider ConfigureServices(IServiceCollection services)
        {
            services.AddApplicationInsightsTelemetry(Configuration);

            if (Configuration.GetValue<string>("OrchestratorType").Equals("K8S"))
            {
                // Enable K8s telemetry initializer
                services.EnableKubernetes();
            }

            // Add framework services.
            services.AddMvc(options =>
            {
                options.Filters.Add(typeof(HttpGlobalExceptionFilter));
            }).AddControllersAsServices();  //Injecting Controllers themselves thru DIFor further info see: http://docs.autofac.org/en/latest/integration/aspnetcore.html#controllers-as-services

            services.Configure<MarketingSettings>(Configuration);

            ConfigureAuthService(services);            

            services.AddHealthChecks(checks => 
            {
                checks.AddValueTaskCheck("HTTP Endpoint", () => new ValueTask<IHealthCheckResult>(HealthCheckResult.Healthy("Ok")));

                var accountName = Configuration.GetValue<string>("AzureStorageAccountName");
                var accountKey = Configuration.GetValue<string>("AzureStorageAccountKey");
                if (!string.IsNullOrEmpty(accountName) && !string.IsNullOrEmpty(accountKey))
                {
                    checks.AddAzureBlobStorageCheck(accountName, accountKey);
                }
            });

            services.AddDbContext<MarketingContext>(options =>
            {
                options.UseSqlServer(Configuration["ConnectionString"],
                                     sqlServerOptionsAction: sqlOptions =>
                                     {
                                         sqlOptions.MigrationsAssembly(typeof(Startup).GetTypeInfo().Assembly.GetName().Name);
                                         //Configuring Connection Resiliency: https://docs.microsoft.com/en-us/ef/core/miscellaneous/connection-resiliency 
                                         sqlOptions.EnableRetryOnFailure(maxRetryCount: 10, maxRetryDelay: TimeSpan.FromSeconds(30), errorNumbersToAdd: null);
                                     });

                // Changing default behavior when client evaluation occurs to throw. 
                // Default in EF Core would be to log a warning when client evaluation is performed.
                options.ConfigureWarnings(warnings => warnings.Throw(RelationalEventId.QueryClientEvaluationWarning));
                //Check Client vs. Server evaluation: https://docs.microsoft.com/en-us/ef/core/querying/client-eval
            });

            if (Configuration.GetValue<bool>("AzureServiceBusEnabled"))
            {
                services.AddSingleton<IServiceBusPersisterConnection>(sp =>
                {
                    var logger = sp.GetRequiredService<ILogger<DefaultServiceBusPersisterConnection>>();

                    var serviceBusConnectionString = Configuration["EventBusConnection"];
                    var serviceBusConnection = new ServiceBusConnectionStringBuilder(serviceBusConnectionString);

                    return new DefaultServiceBusPersisterConnection(serviceBusConnection, logger);
                });
            }
            else
            {
                services.AddSingleton<IRabbitMQPersistentConnection>(sp =>
                {
                    var logger = sp.GetRequiredService<ILogger<DefaultRabbitMQPersistentConnection>>();

                    var factory = new ConnectionFactory()
                    {
                        HostName = Configuration["EventBusConnection"]
                    };

                    if (!string.IsNullOrEmpty(Configuration["EventBusUserName"]))
                    {
                        factory.UserName = Configuration["EventBusUserName"];
                    }

                    if (!string.IsNullOrEmpty(Configuration["EventBusPassword"]))
                    {
                        factory.Password = Configuration["EventBusPassword"];
                    }
                    return new DefaultRabbitMQPersistentConnection(factory, logger);
                });
            }            

            // Add framework services.
            services.AddSwaggerGen(options =>
            {
                options.DescribeAllEnumsAsStrings();
                options.SwaggerDoc("v1", new Swashbuckle.AspNetCore.Swagger.Info
                {
                    Title = "Marketing HTTP API",
                    Version = "v1",
                    Description = "The Marketing Service HTTP API",
                    TermsOfService = "Terms Of Service"
                });

                options.AddSecurityDefinition("oauth2", new OAuth2Scheme
                {
                    Type = "oauth2",
                    Flow = "implicit",
                    AuthorizationUrl = $"{Configuration.GetValue<string>("IdentityUrlExternal")}/connect/authorize",
                    TokenUrl = $"{Configuration.GetValue<string>("IdentityUrlExternal")}/connect/token",
                    Scopes = new Dictionary<string, string>()
                    {
                        { "marketing", "Marketing API" }
                    }
                });

                options.OperationFilter<AuthorizeCheckOperationFilter>();
            });

            services.AddCors(options =>
            {
                options.AddPolicy("CorsPolicy",
                    builder => builder.AllowAnyOrigin()
                    .AllowAnyMethod()
                    .AllowAnyHeader()
                    .AllowCredentials());
            });

            RegisterEventBus(services);

            services.AddTransient<IMarketingDataRepository, MarketingDataRepository>();
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            services.AddTransient<IIdentityService, IdentityService>();

            services.AddOptions();

            //configure autofac
            var container = new ContainerBuilder();
            container.Populate(services);

            return new AutofacServiceProvider(container.Build());
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env,ILoggerFactory loggerFactory)
        {
            loggerFactory.AddAzureWebAppDiagnostics();
            loggerFactory.AddApplicationInsights(app.ApplicationServices, LogLevel.Trace);

            var pathBase = Configuration["PATH_BASE"];

            if (!string.IsNullOrEmpty(pathBase))
            {
                app.UsePathBase(pathBase);
            }    
            
            app.UseCors("CorsPolicy");

            ConfigureAuth(app);

            app.UseMvcWithDefaultRoute();

            app.UseSwagger()
               .UseSwaggerUI(c =>
               {
                   c.SwaggerEndpoint($"{ (!string.IsNullOrEmpty(pathBase) ? pathBase : string.Empty) }/swagger/v1/swagger.json", "My API V1");
                   c.ConfigureOAuth2("marketingswaggerui", "", "", "Marketing Swagger UI");
               });            

            ConfigureEventBus(app);
        }

        private void ConfigureAuthService(IServiceCollection services)
        {
            // prevent from mapping "sub" claim to nameidentifier.
            JwtSecurityTokenHandler.DefaultInboundClaimTypeMap.Clear();

            services.AddAuthentication(options=>
            {
                options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;

            }).AddJwtBearer(options =>
                {
                    options.Authority = Configuration.GetValue<string>("IdentityUrl");
                    options.Audience = "marketing";
                    options.RequireHttpsMetadata = false;
                });
        }

            private void RegisterEventBus(IServiceCollection services)
        {
            if (Configuration.GetValue<bool>("AzureServiceBusEnabled"))
            {
                services.AddSingleton<IEventBus, EventBusServiceBus>(sp =>
                {
                    var serviceBusPersisterConnection = sp.GetRequiredService<IServiceBusPersisterConnection>();
                    var iLifetimeScope = sp.GetRequiredService<ILifetimeScope>();
                    var logger = sp.GetRequiredService<ILogger<EventBusServiceBus>>();
                    var eventBusSubcriptionsManager = sp.GetRequiredService<IEventBusSubscriptionsManager>();
                    var subscriptionClientName = Configuration["SubscriptionClientName"];

                    return new EventBusServiceBus(serviceBusPersisterConnection, logger,
                        eventBusSubcriptionsManager, subscriptionClientName, iLifetimeScope);
                });
            }
            else
            {
                services.AddSingleton<IEventBus, EventBusRabbitMQ>();
            }

            services.AddSingleton<IEventBusSubscriptionsManager, InMemoryEventBusSubscriptionsManager>();
            services.AddTransient<UserLocationUpdatedIntegrationEventHandler>();
        }

        private void ConfigureEventBus(IApplicationBuilder app)
        {
            var eventBus = app.ApplicationServices.GetRequiredService<IEventBus>();
            eventBus.Subscribe<UserLocationUpdatedIntegrationEvent, UserLocationUpdatedIntegrationEventHandler>();
        }

        protected virtual void ConfigureAuth(IApplicationBuilder app)
        {
            app.UseAuthentication();
        }
    }
}